Day: 02/14/2014

Being lazy could be genetic say scientists.

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 A mutation in a gene with a critical role in the brain could explain why some people are “couch potatoes” according to researchers.
Scientists in China and Scotland have made what is being called a “key discovery”, which centres on the system that regulates physical activity levels.

The teams are hopeful that the study could help “millions of patients”.

Based on the findings published in the ‘PLOS Genetics’ journal, pills could be developed in the future which would motivate those who are less inclined to exercise.

While the experiments were conducted on mice, 400 overweight Chinese patients were also screened for metabolic syndrome, with scientists finding that two of them had mutations in the gene.

To make their discovery, scientists compared normal mice with those that had a mutation in a gene called SLC35D3, and found that it produces a protein which plays a key signalling role in the brain’s dopamine system, affecting the regulation of  physical activity.

Mice with this gene had far fewer of this type of dopamine receptor on the surfaces of their brain cells. It was instead stuck within in the cell, leaving the signal process unable to function.

But when the affected mice were treated with a drug that activates dopamine receptors, the problem was reversed and the mice became more active and lost weight.

Scientists think the SLC35D3 gene mutation could explain why people exercise less, and are overweight

Scientists think the SLC35D3 gene mutation could explain why people exercise less, and are overweight
Study leader Professor Wei Li, of the Institute of Genetics and Developmental Biology (IGDB) in Beijing, said he was excited about the findings.

“We discovered that mice with this gene mutation were typical couch potatoes,” he said.

“They walked only about a third as much as a normal mouse, and when they did move they walked more slowly.

“The mice became fat and they also developed other symptoms similar to a condition in people called metabolic syndrome – a medical term for those with a combination of risk factors related to diabetes, high blood pressure and obesity,” he explained.

He added that the discovery could signal a change in attitudes towards obesity.

“A long-standing prescription in combating obesity is to mind your mouth and move your legs. However, genetics contributes to the reluctance to move in some obese people. Medical treatments will in the future be tailored to fit a person’s individual genetic make-up.”

Co-author of the research paper Professor John Speakman, who works between the University of Aberdeen and the IGDB, said: “Although only about one in 200 people may have these ‘rare’ mutations, there are a very large number of people worldwide that have metabolic syndrome.

“Consequently, the population of sufferers that may benefit from being treated with dopamine receptor drugs runs into many millions of patients.”

Male sexual orientation influenced by genes, study shows

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Genes examined in study are not sufficient or necessary to make men gay but do play some role in sexuality, say US researchers
  • Gay pride parade in Seattle
Boy Scouts at a gay pride parade in Seattle. Photograph: Elaine Thompson/AP

A study of gay men in the US has found fresh evidence that male sexual orientation is influenced by genes. Scientists tested the DNA of 400 gay men and found that genes on at least two chromosomes affected whether a man was gay or straight.

A region of the X chromosome called Xq28 had some impact on men’s sexual behaviour – though scientists have no idea which of the many genes in the region are involved, nor how many lie elsewhere in the genome.

Another stretch of DNA on chromosome 8 also played a role in male sexual orientation – though again the precise mechanism is unclear.

Researchers have speculated in the past that genes linked to homosexuality in men may have survived evolution because they happened to make women who carried them more fertile. This may be the case for genes in the Xq28 region, as the X chromosome is passed down to men exclusively from their mothers.

Michael Bailey, a psychologist at Northwestern University in Illinois, set out the findings at a discussion event held in conjunction with the annual meeting of the American Association for the Advancement of Science in Chicago on Thursday. “The study shows that there are genes involved in male sexual orientation,” he said. The work has yet to be published, but confirms the findings of a smaller study that sparked widespread controversy in 1993, when Dean Hamer, a scientist at the US National Cancer Institute, investigated the family histories of more than 100 gay men and found homosexuality tended to be inherited. More than 10% of brothers of gay men were gay themselves, compared to around 3% of the general population. Uncles and male cousins on the mother’s side had a greater than average chance of being gay, too.

The link with the mother’s side of the family led Hamer to look more closely at the X chromosome. In follow-up work, he found that 33 out of 40 gay brothers inherited similar genetic markers on the Xq28 region of the X chromosome, suggesting key genes resided there.

Hamer faced a firestorm when his study was published. The fuss centred on the influences of nature and nurture on sexual orientation. But the work also raised the more dubious prospect of a prenatal test for sexual orientation. The Daily Mail headlined the story “Abortion hope after ‘gay genes findings’ “. Hamer warned that any attempt to develop a test for homosexuality would be “wrong, unethical and a terrible abuse of research”.

The gene or genes in the Xq28 region that influence sexual orientation have a limited and variable impact. Not all of the gay men in Bailey’s study inherited the same Xq28 region. The genes were neither sufficient, nor necessary, to make any of the men gay.

The flawed thinking behind a genetic test for sexual orientation is clear from studies of twins, which show that the identical twin of a gay man, who carries an exact replica of his brother’s DNA, is more likely to be straight than gay. That means even a perfect genetic test that picked up every gene linked to sexual orientation would still be less effective than flipping a coin.

While genes do contribute to sexual orientation, other multiple factors play a greater role, perhaps including the levels of hormones a baby is exposed to in the womb. “Sexual orientation has nothing to do with choice,” said Bailey. “We found evidence for two sets [of genes] that affect whether a man is gay or straight. But it is not completely determinative; there are certainly other environmental factors involved.”

Last year, before the latest results were made public, one of Bailey’s colleagues, Alan Sanders, said the findings could not and should not be used to develop a test for sexual orientation.

“When people say there’s a gay gene, it’s an oversimplification,” Sanders said. “There’s more than one gene, and genetics is not the whole story. Whatever gene contributes to sexual orientation, you can think of it as much as contributing to heterosexuality as much as you can think of it contributing to homosexuality. It contributes to a variation in the trait.”

Qazi Rahman, a psychologist at King’s College London, said the results were valuable for further understanding the biology of sexual orientation. “This is not controversial or surprising and is nothing people should worry about. All human psychological traits are heritable, that is, they have a genetic component,” he said. “Genetic factors explain 30 to 40% of the variation between people’s sexual orientation. However, we don’t know where these genetic factors are located in the genome. So we need to do ‘gene finding’ studies, like this one by Sanders, Bailey and others, to have a better idea where potential genes for sexual orientation may lie.”

Rahman rejected the idea that genetics research could be used to discriminate against people on the basis of their sexual orientation. “I don’t see how genetics would contribute more to the persecution, discrimination and stigmatisation of lesbian, gay, bisexual and transgender people any more than social, cultural or learning explanations. Historically, the persecution and awful treatment of LGBT groups has been because politicians, religious leaders and societies have viewed sexual orientation as ‘choice’ or due to poor upbringing.”

Steven Rose, of the Open University, said: “What worries me is not the extent, if at all, to which our genetic, epigenetic or neural constitution and development affect our sexual preferences, but the huge moral panic and religious and political agenda which surrounds the question.”

Talking to babies boosts their brain power, studies show.

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Children whose parents speak to them least fare worst in language tests, lagging behind by up to six months at age two.
  • A newborn baby

Reading bedtime stories to babies and talking to them from birth boosts their brain power and sets them up for success at school, researchers say.

Studies on babies and toddlers found that striking differences emerged in their vocabularies and language processing skills as early as 18 months old.

Children whose parents spoke to them least came out worst in language tests, and at 24 months old some lagged behind their contemporaries by up to six months. The handicap often stayed with the children and influenced how well they did at school over the next six years.

Prof Anne Fernald, a developmental psychologist at Stanford University, said chatting with infants helped them grasp the rules and rhythms of language at an early age and provided them with a foundation to build up an understanding of how the world worked.

Repetition helped children to remember words, while learning relationships between words, such as “the horse pulls the cart”, helped them to construct a picture of the world that paid dividends when they reached school age.

“You need to start talking to them from day one,” Fernald said at theAmerican Association for the Advancement of Science annual meeting in Chicago. “You are building a mind, a mind that can conceptualise, that can think about the past and the future.”

Fernald described a series of experiments in which she tested children’s language processing skills. In one of the tests, babies and toddlers sat on their parents’ laps in front of a computer that displayed pictures of a baby and a dog side by side.

The researchers used slow-motion video cameras to record how quickly the children shifted their gaze from the wrong image to the right one when told to “look at the baby” or “look at the doggy”. Half of the time they were already looking at the right image.

The test measured the children’s ability to process language information. In the youngest children there was a pause before they looked at the right picture. But as their language skills developed, they shifted their gaze much faster, until they fixed on to the right image before the word baby or dog had been finished.

In one study, Fernald found that the slowest children were 200 milliseconds slower to find the right picture than the fastest ones. The different speeds were down to how much their parents talked with them. When parents chatted more with infants, their children’s language processing improved and they learned new words more swiftly.

Though the difference in performance was marginal, it had a striking effect on the children’s readiness for school, with some children being more than two years behind others in verbal and memory skills by the age of five.

Fernald said children developed language best when their parents or carers involved them in conversations around things the children found interesting. She said plonking a child in front of the TV or giving them an iPad to play with was no substitute for a conversation that centred on the child and their interests, and might even have damaging effects on the children’s language development.

“Parents who talk more to their kids are more likely to realise their developmental potential,” Fernald said. “You are obligated to feed them, wash them, and clothe them. Talk to them while you are doing it. We are not saying quit your job and home school them.”

Prof Erika Hoff, a developmental psychologist at Florida Atlantic University, said parents should not restrict their conversations to simplistic baby talk. Rich and complex language, with adjectives and subordinate clauses, helped them to learn the complex structure of language. “Children cannot learn what they don’t hear,” she said.

Zebedee scanner lets police build 3D maps of crime scenes in minutes

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The Australian technology, already being used by Queensland police, could help vividly illustrate crime scenes to juries

Police may be able to build 3D maps of crime scenes in as little as 20 minutes, thanks to new Australian technology.

The handheld Zebedee scanner, developed by the CSIRO, uses a powerful laser to sweep an environment and create a 3D map accurate to the centimetre.

The scanner had already been used and was saving police “many thousands of hours in investigation”, Queensland police commissioner Ian Stewart said at the device’s official launch on Friday.

Zebedee scanner CSIRO
The Zebedee scanner is a handy crime-fighting tool. 

He said the scanner would be particularly useful in crime scenes involving fatal traffic accidents, unsteady terrain or rough weather, where evidence might quickly degrade.

While the scanner wouldn’t replace traditional police methods of solving crimes, Stewart said it would lead to “faster capture of accurate information in our investigation process. That gives our people time to do other things”.

It would also be used to vividly illustrate crime scenes to juries.

The device is named after a character in the BBC animated series The Magic Roundabout, who, like the scanner, rested on springs.

The technology was developed in Brisbane. Queensland police are the first law enforcement organisation in the world to take it up.

The CSIRO says the next step is to make the Zebedee scanner airborne, so that it could access and explore remote crime scenes.

Termites inspire robot builders

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The “termite” robots in action – speeded up 5 x and then 15 x real-time

US scientists have developed small robots that behave much like termites.

The insects build impressive, metres-high structures even though they can follow only simple rules and have no knowledge of an overall plan.

The Harvard researchers’ robot brick-layers do something similar, sensing just the immediate area and taking limited cues from each other.

Nonetheless, as a report in Science magazine shows, the machines can also build large, coherent structures.

The researchers say this decentralised approach to robot programming can have some major advantages over very sophisticated systems.

The team gives the example of swarms of construction bots being sent into hazardous environments, such as in disaster zones or out into space.

In these types of settings, if one or more machines is destroyed, the others can continue to work together to complete the task.

 Contrast this with a complex robot following high-levels commands. If it fails for some reason, the whole endeavour might be doomed.

“We’re not going to Mars anytime soon, but a more medium-term application might be to use similar robots in flood zones to build levees out of sandbags,” said lead author Dr Justin Werfel from the Wyss Institute for Biologically Inspired Engineering at Harvard University.

“That’s a kind of classic of robotics: you want to use them in situations that are dirty, dangerous and dull.”

Dr Werfel was summarising his research here at the annual meeting of the American Association for the Advancement of Science (AAAS).

Environment driver

He and colleagues are addressing one type of challenge in robotics – that of finding low-level rules that can be followed by machines to give specific, predictable outcomes.

In doing so, the team is borrowing a concept from the world of social insects called “stigmergy”.

This is the idea that coordinated behaviour can arise from information left in the environment.

Termite mound
Termites are champion construction workers

When termites build their mounds, they do so by reacting to their surroundings.

An insect will pick up a lump of earth and transport it to a location. If the location is already filled, it just moves on to the next site and dumps the earth there.

Chemical trails left by the termites in front, and the very shape of the rising mound, guide the workers following behind.

The Harvard team has designed algorithms based on stigmergy for their brick-laying machines.

The scientists specify a particular structure – be that a pyramid or a castle – and the system then automatically generates the low-level rules the climbing robots must follow to guarantee the production of that structure.

Individually, the 18cm-long bots need very little information.

“They have only four simple types of sensors: infrared, ultrasound, an accelerometer for climbing, and tactile sensing – push buttons. That makes them robust and easy to program,” said team-member Kirstin Petersen from the Harvard School of Engineering and Applied Sciences.

They sense the presence of bricks, other nearby bots and the grid space as they move through it.

Evolution probe

They build staircases with their bricks and walk up and down them.

But, importantly, they perceive only their immediate vicinity. They have no information on the current state of the overall structure or the actions of more distant robots.

“They have some traffic rules that tell them how to move through the work space, and these correspond to the particular type of structure being built. That is, if you ask them to build something else, the traffic rules will be different. And they also have some safety checks that ensure they never put bricks that back them into a corner, such as building a cliff they can’t then climb over,” explained Dr Werfel.

Bots can be removed or even added mid-task and it makes no difference. Likewise, if the structure experiences damage mid-erection, the bots merely resume construction at that point and carry the build to completion.

“You can see how this is more robust,” added Dr Werfel. “If you send [the sophisticated Star Wars robot] C-3PO and it is destroyed, you’re out of luck. But if you send an army of ants and half get swept away by the river, the rest can keep on working.”

Commenting, Dr Judith Korb from the University of Freiburg, Germany, said it was conceivable such robots could also be used to turn the study back on living things and the mechanisms of evolution.

“It’s possible you might use this program to test whether the insects do things in an optimal way. It may be that evolution has constrained them such that they follow very good solutions but not quite the best.”

Bio-inspired climbing robots

 

$1 million mistake: Becoming a doctor.

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 If you are brilliant, ambitious and gifted in science, you may consider becoming a doctor. If so, think twice. According to a new survey by personal finance site NerdWallet, most doctors are dissatisfied with the job, and less than half would choose a career in medicine if they were able to do it all over again.

There are many reasons for the dissatisfaction, said Christina Lamontagne, vice president of health at NerdWallet. Most doctors enter the field thinking they’ll be able to spend most of their time healing the sick. Yet the paperwork burden on doctors has become crushing, and could become even more complicated under the Affordable Care Act.

“Administrative tasks account for nearly one-quarter of a doctor’s day,” Lamontagne said. “With additional liability concerns and more layers in health care, we can understand the drain this takes.”

Doctor: Patients should take active role in care

Worse, the cost of becoming a doctor has soared, with higher education expenses leaving the average newly minted physician with $166,750 in medical school debt, while average salaries are declining. Nearly one-third of doctors — 28 percent – saw a cut in pay last year, according to NerdWallet’s research.

To be sure, pay is still high, with of six-figure positions in the country, according to government data. But it also takes between 11 and 14 years of higher education to become a physician. That means the typical doctor doesn’t earn a full-time salary until 10 years after the typical college graduate starts making money.

That lost decade of work costs a cool half-million dollars, if you assume this individual could have earned just $50,000 annually, and the typical medical school candidate is smart and successful enough to earn considerably more. Add in the time and cost it takes to pay off medical school debt and a dissatisfied physician may well consider pursuing medicine a $1 million mistake. (This assumes the average $166,750 medical school debt  takes 30 years to repay at 7.5 percent interest — a total cost of $419,738.)

Moreover, primary care physicians — those who go into pediatrics, family and internal medicine — earn barely more than the amount they accumulated in medical school debt, between $173,000 and $185,000, according to the study that looked at data from George Washington University’s School of Public Health, the American Association of Medical Colleges and Medscape.

The least satisfied physicians are those who go into internal medicine, according to the study. On average, these doctors see two patients every hour while spending 23 percent of their time on paperwork. They work an average of 54 hours per week, take home about $185,000 annually, and a fifth have seen a decrease in pay. Just 19 percent would choose the same specialty, and only one-third would choose a medical career if they had to do it over.

“The frustrations that patients have about not getting enough time with their doctor is mirrored by the frustration their doctors have with not having enough time to spend with their patients,” LaMontagne said.

  • The best paid doctors are orthopedic surgeons, who take home an average of $405,000 annually. The most satisfied appear to be neurologists, who earn an average of $216,000, while working an average of 55 hours per week. Sixty-percent would choose the same specialty, and 53 percent would go into medicine again. Oncologists — the doctors who treat cancer patients — are also generally satisfied with medicine and their jobs, with 62 percent saying that they would go into medicine and 57 percent reporting that they would choose oncology as a specialty.

Radiologists are the physicians most likely to have suffered a pay cut in the past year, with 42 percent reporting a decline in salary. However, they’re also among the best-paid doctors, earning an average of $349,000. More than half would both choose to be doctors again and choose the same specialty.

The doctors who work the longest hours are cardiologists, who report being on the job 60 hours per week. Some 54 percent would choose the same medical specialty, but only 44 percent would go into medicine again if they did it over. The average cardiologist earns $357,000 annually, though 39 percent have seen a cut in pay in the past year.

Those least likely to have suffered a pay cut are emergency doctors, who earn an average of $270,000 and work an average of 46 hours per week. Just 19 percent of emergency doctors suffered a cut last year, but only 41 percent would go into medicine or emergency medical care again.

Across all specialties, physicians see roughly 13 patients per day, work 52 hours per week and earn an average of $270,000. However, family and emergency doctors see nearly 75 percent more patients than anesthesiologists.

Is Radioactive Hydrogen in Drinking Water a Cancer Threat?

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Add two extra neutrons to the lightest element and hydrogen becomes radioactive, earning the name tritium. Even before theThree Mile Island accident in 1979 regulators worried that this ubiquitous by-product of nuclear reactors could pose a threat to human health. The U.S. Environmental Protection Agency (EPA) was only seven years old when it put the first rules on the books for tritium in 1977. But a lot has happened in the intervening decades, and it is not just a longer list of nuclear accidents.

braidwood-nuclear-power-plant

The Chernobyl and Fukushima meltdowns let loose plenty of tritium, but so have a seemingly endless series of leaks at aging reactors in the U.S. and elsewhere. Such leaks have prompted the EPA to announce on February 4 plans to revisit standards for tritium that has found its way into water—so-called tritiated water, or HTO—along with risk limits for individual exposure to radiation and nuclear waste storage, among other issues surrounding nuclear power.

The agency’s recent announcement in the Federal Register notes that tritium levels as high as 3.2 million picocuries per liter (pCi/L) in ground water have been reported to the U.S. Nuclear Regulatory Commission (NRC) at some nuclear facilities. (A curie is a unit of radiation emission; a picocurie is one trillionth of a curie.) That is 160 times higher than the standard set back in 1977 by the fledgling EPA—and the NRC has made measurements even higher at some nuclear facilities. “Because of these releases to groundwater at these sites, and related investigations, the agency considers it prudent to reexamine its initial assumption in 1977 that the water pathway is not a pathway of concern,” the EPA stated in its filing.

This new evaluation is likely to prove challenging, however, as tritium is difficult to get a grip on from both a radiological and human health perspective. On the one hand, there is evidence that the risk from tritium is negligible and current standards are more than precautionary. On the other, there is also some evidence that tritium could be more harmful than originally thought.

Or, as a health physicist who has studied tritium for years observes, in the 1970s, the EPA did not rely on any health studies in setting its original standards. Instead, the EPA back-calculated acceptable levels of tritium in water from the radiation exposure delivered by already extant radionuclides from nuclear weapons testing in surface waters. “It’s not a health-based standard, it’s based on what was easily achievable,” remarks David Kocher of the Oak Ridge Center for Risk Analysis, who has evaluated health risks from tritium and spent 30 years at Oak Ridge National Laboratory. The standard of 20,000 pCi/L of drinking water made compliance easy. “No drinking water anywhere was anywhere close, so it cost nothing to meet.”

By the EPA’s calculations, the 1977 standard should result in an extra radiation dose of less than four millirems, or 40 microsieverts per year, about the amount from a chest X-ray.  (A rem is a dosage unit of x-ray and gamma-ray radiation exposure; one sievert equals 100 rems.) But the standard begs the question: is tritium safe to drink?

Natural background
The EPA will have to take into account complex but sparse data about tritium exposures in formulating new standards. Calculations of exposure levels must take into account not just the levels in waters around nuclear plants but also how much drinking water exposure there is, as well as radiation from natural sources.

High in the atmosphere cosmic rays produce four million curies worth of tritium each year. This atmospheric tritium rains out into surface waters. Nuclear power plants the world over produce roughly the same amount annually, although production (and releases) vary among facilities. For example, the Beaver Creek nuclear power facility in Pennsylvania is the biggest producer of tritiated water in the U.S., per NRC records, churning out roughly 1.5 curies worth per megawatt of electricity produced. Even more escapes in steam from power plants like Palo Verde in Arizona, whose three reactors combine to billow out more than 2,000 curies worth of tritiated steam per year.

But both nuclear power plants and cosmic rays are outweighed by orders of magnitude by the legacy of nuclear bomb testing. Using tritium triggers to explode thermonuclear bombs aboveground produced copious quantities of atmospheric tritium. For every megaton of nuclear blast, roughly seven megacuries of tritium resulted. Despite an end to aboveground testing, leading to a peak in tritium production in 1963, bomb-made tritium lingers, decaying away over a half-life of 12 years. For tritium levels to reach under 1 percent of the original amount released by nuclear weapons testing will thus take seven half-lives, or 84 years. “Setting off all those hydrogen bombs aboveground sent a tremendous pulse into the atmosphere,” notes Kocher, who is also a member of the National Council on Radiation Protection and Measurement. “It’s basically everywhere.”

In fact, everyone drinks tritiated water. “People are exposed to small amounts of tritium every day, since it is widely dispersed in the environment and in the food chain,” as the EPA notes in its public information on the radionuclide.

That bomb-made tritium will eventually decay away completely (presuming the test ban holds), leaving power plants and cosmic rays as the major sources, along with minor contributions from the tritium in photoluminescent signs and the like. But nuclear power plants have not done a good job of containing tritium, whether from steam or water leaks at U.S. plants. In 2005 a group of farmers in Illinois successfully sued utility Exelon for tritiated water escaping from the Braidwood nuclear power plant that had contaminated their wells, even though the levels were below those set by the EPA.

And there is at least 400,000 cubic meters of tritiated water now in storage at Japan’s wrecked Fukushima Daiichi nuclear power complex, which suffered multiple meltdowns after the 2011 earthquake and subsequent tsunami. A suite of technologies there filter out 62 different radioactive particles created by the Fukushima meltdowns—leaving out only tritium, largely because it is difficult and expensive to separate water from water. Companies such as Kurion, which already helps filter out radionuclides like cesium, suggest that they have a solution if the Japanese want to eliminate the tritium as well. “It’s up to TEPCO [the utility] and the Japanese people to decide what they want to do with that water,” says materials scientist Gaetan Bonhomme, vice president of strategic planning and initiatives at Kurion. “It is a radionuclide and it does cause public concern.”

The Kurion process concentrates the radionuclide in a small volume of water. A proprietary material then captures the tritium and stores it—and will not release it until heated above 500 degrees Celsius. “It’s stable in an accident,” Bonhomme notes.

The technology could be applied wherever tritium is produced, including aging nuclear reactors in the U.S. It is the hope of Bonhomme and others that by offering a solution for tritium and other nuclear wastes, they can help ease fears of fission as a source of electricity. But any treatment will be more expensive than simply dumping tritiated water. “If it was really all about science, we would be releasing most of tritium from nuclear power in the water stream, because that’s the best way to dilute it,” Bonhomme admits.

So the question becomes: Is treating for tritium worth it? And that answer depends on the risk.

The big C
Cancer is the main risk from humans ingesting tritium. When tritium decays it spits out a low-energy electron (roughly 18,000 electron volts) that escapes and slams into DNA, a ribosome or some other biologically important molecule. And, unlike other radionuclides, tritium is usually part of water, so it ends up in all parts of the body and therefore can, in theory, promote any kind of cancer. But that also helps reduce the risk: any tritiated water is typically excreted in less than a month.

Some evidence suggests the kind of radiation emitted by tritium—a so-called beta particle—is actually more effective at causing cancer than the high-energy radiation such as gamma rays, even though skin can block a beta particle. The theory is that the low-energy electron actually produces a greater impact because it doesn’t have the energy to travel as far and spread its impact out. At the end of its atomic-scale trip it delivers most of its ionizing energy in one relatively confined track rather than shedding energy all along its path like a higher-energy particle. This is known as density of ionization, and has been shown with the similar form of radiation called analpha particle.

Ionization is what makes radiation dangerous for human health. Essentially, the radioactive particle smashes into the atom or molecule and pushes out an electron or other particle, leaving that atom or molecule in a charged or ionized state. These charged molecules can then cause other damage as they interact with other atoms and molecules. That includes damage to DNA, genes and other cellular mechanisms. Over time this DNA instability results in a higher chance of cancer. As a result, scientists work under the assumption that any amount of radiation poses a health risk.

Density of ionization suggests tritium exposure may have an increased risk of causing cancer. The National Institute for Occupational Safety and Health calculates compensation due energy workers who develop cancers that may have been caused by exposure to ionizing radiation with such enhanced biological effectiveness of tritium in mind as does the fund for the 200,000 or so personnel who served at nuclear test sites, the atomic veterans (although few had any tritium exposure).

But there is no definitive epidemiological study to assess the true risk of tritium, and animal studies are also lacking. The cancer rates in Japanese survivors of the nuclear bombs dropped on Hiroshima and Nagasaki can reveal little because they were not exposed to tritium either. “You need huge study populations to have any chance of seeing anything,” Kocher notes, and that money is simply unavailable. “There is no compelling need to spend the money required to do this.”

To make matters even more tricky, tritium’s radioactivity is difficult to detect. Because the electron tritium spits out is not a penetrating or high-energy particle, it is hard for radiation monitoring devices to even detect. That makes measuring the radiation dose from tritium difficult. “Dosimetry has been a problem,” Kocher notes. “I think a definitive epidemiological study is probably impossible.”

In fact, the current National Research Council effort to determine cancer risk from living near a nuclear power plant in the U.S. will not examine the specific risk from tritium leaks. “Our study will not be examining the cancer risks from the leaks as separate events, so it will not be a useful source of information for the purpose of linking cancer occurrence or death from cancer with tritium ingestion,” noted Ourania Kosti, director of the ongoing study and a senior program officer at the Institute of Medicine of the National Academies, in an e-mail response.

This lack of data may complicate the EPA’s new rulemaking. Federal regulators might choose to maintain existing standards (as has been done after re-evaluations in the past) or look at what individual states have done, although everywhere the picture remains clouded by uncertainties.

Some states, such as Colorado and California, have set lower goals for the tritium in drinking water. For example, the U.S. Department of Energy has agreed to clean surface waters surrounding its former nuclear weapons production facility Rocky Flats in Colorado to the level of 500 pCi/L. By comparison, the levels of tritiated water found in a monitoring well near the leaking Oyster Creek nuclear power plant in New Jersey reached 4.5 million pCi/L, although no tritiated water has been detected off-site as yet.

At Braidwood in Illinois the tritiated water had spread via leaks in a plume, reaching levels of 1,600 pCi/L in the groundwater under nearby farm fields. If consumed for an entire year, tritiated water at that level would result in an extra dose of radiation of roughly 0.3 millirem. That is 1,000 times smaller than the amount of radiation from natural sources absorbed by the average American in a year and 12 times smaller than the dose absorbed during a single flight across the U.S. For comparison, one chest x-ray, which also falls into the class of radiation that appears to be more biologically effective, results in a dose of four millirem.

The potential innocuousness raises the question of whether more stringent standards are really needed—which is the determination the EPA made the last time it revisited these standards at the end of the 20th century. “I think the levels of tritium in drinking water today are low enough that I wouldn’t worry,” Kocher says. “The good news about tritium is that: even if you inhale or ingest an awful lot, it is going to flush out of your body.” He adds: “Just have a few beers and you’re done.”

Neuropathic pain: mechanisms and their clinical implications.

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Abstract

Neuropathic pain can develop after nerve injury, when deleterious changes occur in injured neurons and along nociceptive and descending modulatory pathways in the central nervous system. The myriad neurotransmitters and other substances involved in the development and maintenance of neuropathic pain also play a part in other neurobiological disorders. This might partly explain the high comorbidity rates for chronic pain, sleep disorders, and psychological conditions such as depression, and why drugs that are effective for one condition may benefit others. Neuropathic pain can be distinguished from non-neuropathic pain by two factors. Firstly, in neuropathic pain there is no transduction (conversion of a nociceptive stimulus into an electrical impulse). Secondly, the prognosis is worse: injury to major nerves is more likely than injury to non-nervous tissue to result in chronic pain. In addition, neuropathic pain tends to be more refractory than non-neuropathic pain to conventional analgesics, such as non-steroidal anti-inflammatory drugs and opioids. However, because of the considerable overlap between neuropathic and nociceptive pain in terms of mechanisms and treatment modalities, it might be more constructive to view these entities as different points on the same continuum. This review focuses on the mechanisms of neuropathic pain, with special emphasis on clinical implications.

Diuretic drug prevents autism in mice and rats.

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Rodent study supports controversial clinical trial showing beneficial effects in children with the disorder.

Children with autism typically begin showing obvious symptoms, such as trouble making eye contact and slow language development, a year or more after birth. A study in mice and rats now hints that prenatal drug treatment could head off  these problems.

The findings, reported today in Science1, do not suggest that autism spectrum disorders can be prevented in children. But researchers not involved in the study say that they add support to a controversial clinical trial suggesting that some children with autism benefited from taking a common diuretic medication called bumetanide2.

In that trial, a team led by neuroscientist Yehezkel Ben-Ari at the Mediterranean Institute of Neurobiology in Marseille gave 60 children bumetanide or a placebo daily for three months. Children who had less severe forms of autism showed mild improvements in social behaviour after taking the drug, and almost no adverse side effects were observed .

But autism researchers greeted the results with caution. Many pointed out that the study did not provide a clear biological mechanism that could explain how the drug improved the symptoms of the disorder.

Improved symptoms

The latest study is an attempt to answer such criticisms by identifying a role for the neurotransmitter GABA. Studies in humans and animals have suggested that GABA, which in healthy people typically inhibits the activity in neurons, is altered in autism and instead activates some brain cells. Ben-Ari’s team hypothesized that the system malfunctions at around the time of birth, when GABA-releasing neurons in the developing brain switch from activating neurons to inhibiting them. A drop in the concentration of chloride ions in neurons makes this switch. Thus, bumetanide, which reduces the levels of chloride in cells, might restore inhibitory GABA function and improve autism symptoms.

To make a stronger case for that hypothesis, Ben-Ari’s team turned to two animal models of autism: mice with a mutation that in children causes fragile-X syndrome (a form of autism) and rats exposed to an anticonvulsant drug while in the womb.  The researchers discovered that, in both models, neurons in a brain area called the hippocampus remained excitatory after birth in response to GABA and contained higher levels of chloride than those in normal rodents.

These problems, however, were reversed when the rodent mothers were given bumetanide one day before giving birth. Their pups also displayed fewer autistic-like behaviours: for example, both rats and mice produced vocalizations more typical of normal rodents. The offspring “have more GABA, low chloride, they have fewer behavioural problems”, says Ben-Ari. The paper did not clarify whether the benefits lasted throughout the animals’ lives.

Treatment prospects

Elizabeth Berry-Kravis, a paediatric neurologist at Rush University Medical Center in Chicago, Illinois, says that the latest study indirectly supports the results of the bumetanide clinical trial. But she says that the findings should be viewed with caution because of developmental differences between humans and rodents. For example, mice and rats are born at a more advanced stage of development than humans.

“This paper is not telling us ‘okay, we’ve got the treatment for autism’,” she says. “Until we roll out a big trial in humans we aren’t going to know whether it’s possible to treat humans later on, when they have a diagnosis.”

A multi-centre clinical trial is now under way in Europe to test bumetanide in children with autism. Ben-Ari is the chief executive of Marseille-based Neurochlore, a company developing treatments for autism, which is funding those trials.

But Andrew Zimmerman, a paediatric neurologist at the University of Massachusetts Medical School in Worcester and co-author of a commentary accompanying the paper3, says that better ways are needed of identifying children who may go on to develop autism before even thinking about trying to prevent the disorder. Marker molecules in amniotic fluid or non-invasive brain imaging have the potential to reveal early signs of autism, he says. “I just hope that people will work first on biomarkers to detect who’s at risk.

Source: Nature

10 Valuable Life Lessons to Learn from Children.

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“The pursuit of truth and beauty is a sphere of activity in which we are permitted to remain children all our lives.” ~ Albert Einstein

I am a Mom to two awesome boys. They have taught me more in the last 7 years than I could have learned in the 25 years I was without children. Here are the top 10 lessons my Children have taught me (so far):

10 Valuable Life Lessons to Learn from Children

1. Keep Discovering. Keep Exploring

From discovering their hands and feet as infants, to discovering that monsters really do not live in the closet or under the bed. From exploring letting go of what has held them up and finding out they can put one foot in front of the other to walk, to exploring a new sport they were so intimidated by before and finding out they are really good at it.  They have taught me to keep exploring and to keep discovering. Discovery can be so rewarding, but we have to be willing to open ourselves to it. We have to continue to spark our curiosities and to stop assuming we know the answers. It is amazing what happens when we approach life knowing we actually know nothing at all.

“We shall not cease from exploration, and the end of all our exploring will be to arrive where we started and know the place for the first time.” ~ T. S. Eliot

2. Be yourself. “…those that mind don’t matter and those that matter don’t mind”

My oldest son has dressed himself since age 2. One summer day at age 3 he decided to wear his bright orange bubble vest along with some shorts and rain boots. We were going to get ice cream and that is how he wanted to go. Hand in hand, we went. There were plenty of people there and all of them looking right at him and smiling (some laughing). He was very comfortable with the attention and was more into the ice cream than at the kids who were staring at him. He was himself. To him, it was about self-expression and it did not matter who laughed or pointed. He was comfortable in his own skin, orange bubble jacket and rain boots. That day, he taught me to be comfortable in mine as well.

“Be yourself; everyone else is already taken.” ~ Oscar Wilde

3. Dance like no one is watching.

Put some dance music on and watch how children react. Most of them don’t think twice about it, they just dance. At weddings, at school dances, at parties, they always dance. They dance with whatever rhythm they may have and they don’t care who is watching. What do the adults do? They stand around and watch the kids or continue their conversation. I have joined my oldest son many of times on a dance floor full of kids. It was fun, I danced with whatever rhythm I thought I had and I danced like nobody was watching.

“Dance as though no one is watching you, Love as though you have never been hurt before, Sing as though no one can hear you, Live as though heaven is on earth.” ~ Souza

4. Cuddling is underrated.

It is my pleasure to cuddle with my children. I enjoy having their little hands in mine. I enjoy feeling their little arms around my neck and having them curled up on my lap. Whenever they want to cuddle, I CUDDLE! It is those moments I treasure most because one day, they will be too big to curl up on my lap and too cool to put their arms around my neck.

5. Keep Dreaming and develop a plan. 

I asked my son what he wanted to be when he grows up and he said a DJ and a Car Designer. He has elaborate plans on how he will achieve this. He is 7 years old and this dream is completely attainable for him. I admire this and have told him I support him in whatever he wants to do and to let me know what he needs from me so he can become what he wants to be. As adults, we become so distracted by our responsibilities (job, children, etc) that we have let go of our long lost dreams of becoming whatever it was we wanted to be. I understand being an astronaut may be far reaching for many of us now, but studying astronomy is not. Looking through a telescope and admiring the universe is not. You had dreams of becoming a musician? Pick up an instrument, take some lessons and sing away! Show your children that dreams do not have to stay dreams.

“All our dreams can come true, if we have the courage to pursue them.” ~ Walt Disney

6. Have Patience.

I have learned patience from the day I found out I was pregnant. From those long 40 weeks of pregnancy to the 15+ labor hours with my first and a nice 8 labor hours with my second. Patience is learned early. Patience was also learned while up at 4am with a wide awake infant and while teaching my 5 year old how to read the words Cow, Car and Dog. Although I have not mastered patience, my children are sure to help me every single day.

“Our patience will achieve more than our force.” ~ Edmund Burke

7. A messy home is not the end of the world.

I would not consider myself OCD, however, I feel a clean home is a  happy home. I say this knowing my children and the dog completely disagree.  I like things in their place, my floors spotless and the kitchen sink free of dirty dishes. With this said, I also now understand, toys are best all over the place and keep the kids entertained while I try to prepare dinner. Muddy paw prints on the floor makes for a good laugh after the fact and the mess made by the kids fuels exploration, imagination and discovery. A mess is just that, a mess, it can be cleaned up and is not the end of the world.

8.Take risks.

Jumping from couch to couch, dangling off of monkey bars upside down, rolling right off the bed without the slightest concern of the drop to the floor, attempting to jump into the pool before I make it in to catch them, you get the picture. I am sure there are many more events to come that will give me minor heart attacks, but the fearless attitude a child possess is something to be admired. Although my oldest child is a bit more cautious than other children, the risk taking that children feel comfortable with should be a reminder to us that we will never know the result unless we try it. I am not talking about the skydiving or bungee jumping risks, I am talking about the job change or even that new hair cut risk. Assumptions do not do anything but create a false sense of security or self-doubt. Stop assuming and do it. If you fall, get up clean yourself up and either try again or move on to the next risk you have been contemplating over.

“Children have a lesson adults should learn, to not be ashamed of failing, but to get up and try again. Most of us adults are so afraid, so cautious, so ‘safe,’ and therefore so shrinking and rigid and afraid that it is why so many humans fail. Most middle-aged adults have resigned themselves to failure.” ~ Malcolm X

9. Fill your heart with Love. 

Although this seems cliche, the unconditional love I have for my children is something I only found to be true when I had children. It is so hard to verbalize. It is a love encompassed by so many other feelings. To name the ones I am able to verbalize best: joy, admiration, respect, appreciation, reward, pride, anxiety, worry, adoration and amazement. I am so very grateful to be able to feel and do the unconditional love I have for them and am even more grateful and humbled that the love I give to them, they return to me every day.

“There are two basic motivating forces: fear and love. When we are afraid, we pull back from life. When we are in love, we open to all that life has to offer with passion, excitement, and acceptance. We need to learn to love ourselves first, in all our glory and our imperfections. If we cannot love ourselves, we cannot fully open to our ability to love others or our potential to create. Evolution and all hopes for a better world rest in the fearlessness and open-hearted vision of people who embrace life.” ~ John Lennon

10. Treasure the Time give to you.

The most important lesson I have learned from my children (so far) is the immeasurable value of time and to treasure and enjoy the time given to you. The last 7 years of motherhood have gone so very fast. The quote “The days are long, but years are short” is an understatement. Yes, those sleepless nights with my youngest makes my days very long; but he is now on the verge of walking! When did that happen?? Yes, those days when my oldest has an attitude because he would rather play a video game than head to the park for some outside play are long; but he is headed to the 3rd grade in the fall. When did that happen??

Time is constant, the hours pass, the years pass and I am consciously making and effort to ENJOY my time with my children. I enjoy the time I discover and explore with them; the time I am not feeling so good about myself and my oldest tells me I am the most beautiful woman in the world, the time we have a dance party in the kitchen; the time we all cuddle as a family in pjs watching a movie; the time we share our dreams and talk about our plans to reach them; the time when my patience is tested and I get through it a little more patient than the day before; the time I try to clean the house, step on toys and trip over a remote control car; the time when I watch my oldest try to swim from one side of the pool to the other unassisted for the first time and the time I hear I love you thiiiiiissss much and I reply “I love you more!” and hear back “I love YOU more!”. Time is a gift given to us, we have the responsibility of doing something wonderful with it. Create memories, give love and most importantly, ENJOY.

What lessons have you learned from interacting with children?