21st Mar 2014, 04:36 PM #911
Re: Health Bulletin
Humans can detect 1 trillion smells
New research has found that humans are capable of differenciating between at least one trillion different odours and not a mere 10,000 as is popularly thought. Scientists from the Howard Hughes Medical Institute (HHMI) reached this estimate after concocting various smells in the lab and testing individuals' ability to recognize the differences.
"Our analysis shows that the human capacity for discriminating smells is much larger than anyone anticipated," said Howard Hughes Medical Institute (HHMI) investigator Leslie Vosshall, who studies olfaction at the Rockefeller University.
Vosshall and her colleagues published their findings March 21, 2014, in the journal Science. "I hope our paper will overturn this terrible reputation that humans have for not being good smellers," she says.
The 10,000 odours smelling capacity was estimated back in the 1920s without any data and it has bothered scientists like Vosshall. For one thing, it didn't make sense that humans should sense far fewer smells than colours. In the human eye, Vosshall explains, three light receptors work together to see up to 10 million colours. In contrast, the typical person's nose has 400 olfactory receptors.
But no one had tested humans' olfactory capacity.
Vosshall and Andreas Keller, a senior scientist in her lab at Rockefeller University, knew they couldn't test people's reactions to 10,000 or more odours, but they knew they could come up with a better estimate. They devised a strategy to present their research subjects with complex mixtures of different odours, and then ask whether their subjects could tell them apart.
They used 128 different odorant molecules to concoct their mixtures. The scientists presented their volunteers with three vials of scents at a time: two matched, and one different. Volunteers were asked to identify the one scent that was different from the others. Each volunteer made 264 such comparisons.
Afterwards, the scientists tallied how often their 26 subjects were able to correctly identify the odd-man-out. From there, they extrapolated how many different scents the average person would be able to discriminate if they were presented with all the possible mixtures that could be made from their 128 odorants. In this way, they estimated that the average person can discriminate between at least one trillion different doors.
"I think we were all surprised at how ridiculously high even the most conservative lower estimate is," Vosshall says. "But in fact, there are many more than 128 odorants, and so the actual number will be much, much bigger."
22nd Mar 2014, 07:04 PM #912
Re: Health Bulletin
Viper venom clue in Alzheimer's fight
Chandrabora (Russell's Viper). The name strikes fear among even the bravest. But its venom, one of the deadliest in this part of the world, can provide a clue to fighting Alzheimer's disease, scientists at the Council of Scientific and Industrial Research's Indian Institute of Chemical Biology (CSIR-IICB) have discovered.
Lab tests have shown that a component in the highly toxic venom prevents the deposition of proteins in a particular part of the brain that triggers Alzheimer's, say the researchers. Animal tests will begin shortly.
Beta Amyloid peptide deposit in the brain is what leads to Alzheimer's in people over 60. By the time it is detected, it is too late. "We found that another peptide in the venom can degrade this precipitation," said Debasish Bhattacharyya, deputy director, structural biology and bioinformatics. "We purified the component in the venom that was found to be most potent in degrading protein aggregation," added Payel Bhattacharjee, senior research fellow, who wrote the thesis.
The peptide in Russell's Viper venom dissolves the patches in the brain that mark Alzheimer's, say researchers. So far, they have run tests under simulated conditions and are preparing for animal tests.
It's too early to early speculate when the solution will be available in the form of a drug, but the researchers are hopeful that it will be an effective tool in fighting the "silent killer" that is traumatic not just to the patient but all family members.
"Several research works have been done and only 1% of them may translate into drug form. But if we don't try, we'll never know. If it happens, then it will be a boon to millions of families," said Bhattacharyya.
23rd Mar 2014, 02:09 AM #913
Re: Health Bulletin
Anti-anxiety drugs could help 'balance' the autistic brain
Low doses of anti-anxiety drugs could hold the cure for autism. New research in mice suggests that autism is characterized by reduced activity of inhibitory neurons and increased activity of excitatory neurons in the brain, but balance can be restored with low doses of benzodiazepines.
Autism is a complex neuro-developmental disorder which is characterised by poor social skills and an obsession with sameness. It roughly affects one in 88 children -- mainly boys -- according to the US Centers for Diseases Control in Atlanta.
The study, which has been funded by the National Institutes of Health in the US, has been published in Cell Press journal Neuron. "These are very exciting results because they suggest that existing drugs might be useful in treatment of the core deficits in autism," said senior author Dr William Catterall of the University of Washington, Seattle.
His team also found that reducing the effectiveness of inhibitory neurons in normal mice also induced some autism-related deficits. "Benzodiazepine drugs had the opposite effect, increasing the activity of inhibitory neurons and diminishing autistic behaviors,'' said a press release put out by the University of Washington.
"Our results provide strong evidence that increasing inhibitory neurotransmission is an effective approach to improvement of social interactions, repetitive behaviors, and cognitive deficits in a well-established animal model of autism," said Dr Catterall.
23rd Mar 2014, 02:10 AM #914
Re: Health Bulletin
Social groups reduce depression
Developing a sense of belonging could beat the blues.
A new study from the Canadian Institute for Advanced Research says that building a strong connection with a social group helps clinically depressed patients recover and helps prevent relapse.
Depression is emerging as a leading cause for suicides, accounting for between 6 to 10% of the population.
The Canadian institute's Alexander Haslam, lead author Tegan Cruwys and their colleagues at the University of Queensland conducted two studies of patients diagnosed with depression or anxiety. The patients either joined a community group with activities such as sewing, yoga, sports and art, or partook in group therapy at a psychiatric hospital.
In both cases, patients who did not identify strongly with the social group had about a 50 % likelihood of continued depression a month later. But of those who developed a stronger connection to the group and who came to see its members as 'us' rather than 'them,' less than a third still met the criteria for clinical depression after that time. Many patients said the group made them feel supported because everyone was "in it together."
"We were able to find clear evidence that joining groups, and coming to identify with them, can alleviate depression," said Haslam. His research has been published in the Journal of Affective Disorders.
24th Mar 2014, 01:58 AM #915
Re: Health Bulletin
Eating eggs may halt memory loss and lower the risk of dementia
Scientists are investigating whether eating eggs may prevent memory loss and lower the risk of dementia.
In the six-month U.S. study, half of the participants will have two eggs a day, and will be compared with a control group who won’t have eggs.
Both groups will be tested for memory, reasoning, verbal fluency and attention span – a decline in these is a major risk factor for the development of dementia later in life.
Eggs are one of the best sources of two antioxidants, lutein and zeaxanthin, which previous research suggests can improve cognitive function.
The researchers, from Tufts University in the U.S., expect there will be ‘a significant increase’ in the mental functioning in the group given eggs.
24th Mar 2014, 01:59 AM #916
Re: Health Bulletin
Super-laser targets ugly caesarean scars
Laser therapy is being tested as a way to reduce caesarean scarring. One in four births in this country is now by caesarean and the surgery can leave a prominent, raised or even painful scar across the abdomen.
Now, a clinical trial is looking at laser therapy to tackle this. The light is thought to trigger chemical reactions in the skin, which stimulates the growth of new tissue, as well as ‘remodelling’ the scar tissue.
The device being tested is six times more powerful than other types of lasers, and is said to penetrate four times deeper into the abdominal tissue, up to 4mm.
Women on the Danish trial at Aarhus University Hospital will have three treatments – scar thickness will be measured before and after.
24th Mar 2014, 12:37 PM #917
Re: Health Bulletin
Older dads more likely to have uglier children?
Children born to older fathers are not just at an increased risk of autism and some other diseases but are also more likely to be ugly, scientists say. Previous studies have shown that extra-genetic mutations that build up in older men's genes can raise their children's risk of autism, schizophrenia and other diseases. Now researchers say the impact is so strong that it also affects the appearance of those who have older fathers.
"We found a significant negative effect between paternal age and people's facial attractiveness," said Martin Fieder, an anthropologist at Vienna University and one of the research team leaders. "The age of the father at conception is not only a determinant of the risk for certain diseases but also predicts facial attractiveness," Fieder said.
In the study, a group of six men and six women was shown photographs of 4,018 men and 4,416 women, mostly aged 18-20, and asked to rate their attractiveness. The researchers found that subjects with older fathers tended to be consistently rated less attractive than those with younger fathers.
24th Mar 2014, 12:38 PM #918
Re: Health Bulletin
Beer in summer causes kidney stones'
As the mercury starts inching towards the 40 degree C mark, nephrologists here warn against reaching out for that ice-cold glass of frothy beer that may seem like the most refreshing thing on a hot day.
While most beer guzzlers console themselves with the misconception that beer, made mostly of water and malted cereals, contains nutritive and re-hydrating properties, experts say that the hoppy beverage could actually raise the risk for kidney stones.
"It is a popular myth, and one that has led to people here drinking beer instead of water, when thirsty. Beer, like any other alcoholic beverage, acts as a diuretic and removes water from the body. Regular beer drinkers are at higher risk of developing oxalate kidney stones," says nephrologist Shital Lengade.
Ideally, patients with painful kidney stones start trooping into hospitals between July and October, he says. "The stones develop during the summer months, when dehydration levels are high. The symptoms - usually excruciating pain in the abdomen or back-- show up during the monsoon. Many of them admit to drinking beer and alcohol to quench thirst," he explains.
Even beer-lovers can avoid the painful ailment by compensating for liquid lost. "While a minimum water intake of 3 litres per day is advisable during the summer, people who drink alcohol should always drink equal amounts of water as well,' Lengade adds.
The thirst that accompanies the humid Goan summer also keeps other doctors on their toes, with people reaching out to drink any questionable fluid, and ending up with gastro-intestinal diseases.
"We have started receiving a stream of patients with water-borne infections like typhoid and gastroenteritis; in a majority of cases, caused by drinking unboiled water or fruit juices sold on the roadside. The diarrhea leads to further de-hydration, especially in smaller children, who have to be hospitalized and given intravenous fluids," laments Sanjay Altekar, a general physician from Panaji.
Altekar also reports a spike in food poisoning cases, characterized by vomiting, diarrhea, stomach pain and dizziness -- mostly in patients who consume meat and shellfish. Cheryl D'Souza, professor of food and nutrition at Goa's college of home science calls for extra caution while handling food during the hot months. "As the rate of spoilage is very high in this humid weather, people should shop for meat and fish early in the morning. With every passing minute that the protein is left out on the hawker's slab, more micro-organisms grow," she says. "Cooked food should be consumed immediately, and left-overs should be refrigerated - even a few hours of sitting outside could cause it to spoil. When eating out, one should avoid salads and raw, cold foods," she warns.
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25th Mar 2014, 01:47 AM #919
Re: Health Bulletin
Electric stimulation of brain can boost your learning speed
Scientists have found that it is possible to selectively manipulate our ability to learn by applying a mild electrical current to the brain.
Researchers said this effect can be enhanced or depressed depending on the direction of the current, a finding which suggests that electrical stimulus can help people learn new or difficult material more quickly. The medial-frontal cortex is believed to be the part of the brain responsible for the instinctive "Oops!" response we have when we make a mistake. Previous studies have shown that a spike of negative voltage originates from this area of the brain milliseconds after a person makes a mistake, but not why.
Researchers from the Vanderbilt University in US wanted to test the idea that this activity influences learning because it allows the brain to learn from our mistakes. "And that's what we set out to test: What is the actual function of these brainwaves? We wanted to reach into your brain and causally control your inner critic," said psychologist Robert Reinhart. Reinhart and Geoffrey Woodman, assistant professor of psychology, used an elastic headband that secured two electrodes conducted by saline-soaked sponges to the cheek and the crown of the head and applied 20 minutes of transcranial direct current stimulation (tDCS) to each subject.
25th Mar 2014, 12:29 PM #920
Re: Health Bulletin
Too much worry lowers chances of pregnancy: Study
Too much stress and worry may lower the chances of getting pregnant and cause infertility, a new study by researchers of the Ohio University has found. They found that stressed women are nearly 30 percent less likely to get pregnant and twice more likely to be diagnosed as 'infertile'. Stress was indicated by measuring a marker that is found in saliva.
Extending and corroborating their earlier study conducted in the UK that demonstrated an association between high levels of stress and a reduced probability of pregnancy, this work adds new insight by suggesting that stress is associated with an increased risk of infertility. The study findings appear online in the journal Human Reproduction.
Courtney Denning-Johnson Lynch, director of reproductive epidemiology at The Ohio State University Wexner Medical Center, and colleagues found that women with high levels of alpha-amylase — a biological indicator of stress measured in saliva — are 29 percent less likely to get pregnant each month and are more than twice as likely to meet the clinical definition of infertility (remaining not pregnant despite 12 months of regular unprotected
intercourse), compared to women with low levels of this protein enzyme.
Researchers tracked 501 American women ages 18 to 40 years who were free from known fertility problems and had just started trying to conceive, and followed them for 12 months or until they became pregnant as part of the Longitudinal Investigation of Fertility and the Environment (LIFE) Study. Saliva samples were collected from participants the morning following enrollment and again the morning following the first day of their first study-observed menstrual cycle. Specimens were available for 373 women and were measured for the presence of salivary alpha-amylase and cortisol, two biomarkers of stress.
""This is now the second study in which we have demonstrated that women with high levels of the stress biomarker salivary alpha-amylase have a lower probability of becoming pregnant, compared to women with low levels of this biomarker. For the first time, we've shown that this effect is potentially clinically meaningful, as it's associated with a greater than two-fold increased risk of infertility among these women,"" said Lynch, the principal investigator of the LIFE Study's psychological stress protocol.
Lynch said results of this research should encourage women who are experiencing difficulty getting pregnant to consider managing their stress using stress reduction techniques such as yoga, meditation and mindfulness. However, she said that couples should not blame themselves if they are experiencing fertility problems, as stress is not the only or most important factor involved in a woman's ability to get pregnant.
Germaine Buck Louis, director of the Division of Intramural Population Health Research of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the LIFE Study's principal investigator, said, "Eliminating stressors before trying to become pregnant might shorten the time couples need to become pregnant in comparison to ignoring stress. The good news is that women most likely will know which stress reduction strategy works best for them, since a one-size-fits-all solution is not likely."