The new study, certainly not the last word on DNA, was published last week in The EMBO Journal. The music is Chopin’s Minute Waltz, the subject of another post.
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The development of white matter tracts, the nerve bundles that join one brain region to another, is different in babies who go on to develop autism compared with those who do not, according to a new study.
Researchers scanned the brains of infant siblings of children with autism — who have an increased risk of developing the disorder themselves — several times during their first two years of life. The so-called ‘baby sibs’ who go on to receive a diagnosis of autism at 24 months of age have distinct brain patterns at 6 months and abnormal neural development from 6 to 24 months, according to the study. The results were published 17 February in the American Journal of Psychiatry.
“The story is that autism is an unfolding process, not something that happens in the third trimester and then is done,” says lead investigator Joseph Piven, professor of psychiatry at the University of North Carolina-Chapel Hill. “We see the brain changing over time in a dynamic way.”
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Just over a year ago, I wrote about a handful of research groups creating robots that can engage children who have autism using speech, facial expressions or body movements. These ‘social’ bots ranged from a miniature dinosaur and a dancing yellow snowman to several sophisticated, full-size humanoids.
The eclectic collection now includes a boy that can sense when it’s touched, a floating female head that expresses a wide range of emotions and a low-cost fuzzy penguin that can track a child’s eye movements. Descriptions of all three appear in the latest conference proceedings of the IEEE Engineering in Medicine and Biology Society.
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By screening the genomes of hundreds of people with autism and analyzing the effect of newly identified mutations in cultured neurons, researchers have clarified the disorder’s complex link to a gene called SHANK2.
Functional mutations in SHANK2 crop up about twice as often in individuals with autism as in typical controls, according to a study published 9 February in PLoS Genetics.
The SHANK2 protein buttresses the synapse, or junction between neurons. The new findings add to already robust evidence from genetic studies and animal models that synaptic proteins — notably SHANK3, neurexins and neuroligins — are important in autism, the researchers say.
But a more surprising finding helps to explain why not everyone who has a SHANK2 mutation has autism. The three individuals with autism known to carry SHANK2 deletions also carry rare deletions or duplications — so-called copy number variations, or CNVs — in an autism-linked segment of chromosome 15. This supports the idea that autism arises not from a single genetic glitch, but from multiple hits to the genome.
“I think many people are still thinking about the genome like the old black-and-white movies from the 1950s: The good guy was in white, the bad guy was in black, and everybody knew what was going on,” says lead investigator Thomas Bourgeron, professor of genetics at the University of Paris Diderot.
But studies like this show that a ‘bad’ genetic glitch isn’t necessarily the only bad guy.
“When we find a single mutation in a patient with autism, we can’t say that we’re done,” Bourgeron says. “We still have to work on the whole genome of these patients to understand exactly what’s going on.”
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Some 40 years ago, researchers at the University of Missouri were searching for an alternative to the condom — a cheap, trustworthy and reversible form of male birth control.
For their first study, published in 1975, they strapped anesthetized rats, face-down, to a plexiglass platform with a cut-out cup full of water for their dangling scrota. The scientists then exposed the animals’ testicles to a variety of things.
Heat, for example, can kill sperm (which is thought to explain why the testes hang outside of the body). So some of the animals got a 140-degree Fahrenheit water bath for 15 minutes. Others received a dose of infrared radiation, or short blasts of microwaves or ultrasound. After treatment, the animals had constant access to females until they impregnated them.
Rats given the hot water bath didn’t conceive for 35 days. Infrared radiation doubled that sterile window, to 75 days. Sometimes microwave treatment worked, sometimes it didn’t. The best protocol, by far, was ultrasound, which the researchers transmitted through the water cup. One 5-minute exposure to these high-frequency sound waves led to seven months of sterility. Histology studies of the tissue confirmed that the animals showed a big loss of developing sperm at two months post-ultrasound, but were back to normal by 10 months.
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Mental illness is the leading cause of disability in the world, according to the World Health Organization. Even more troubling: Four out of five people with psychiatric disorders live in developing countries, where they have few opportunities for treatment.
That’s certainly the case for autism in Africa, though, like in other resource-poor areas of the world, awareness is beginning to improve. In the past few years, a handful of researchers in various African countries have investigated children with autism. A new review of these reports finds that these children tend to be diagnosed much later than their counterparts in the U.S., and are more likely to be nonverbal.
The review, published in the December issue of the South African Journal of Psychiatry, analyzes six studies: three from Nigeria, the most populous country in Africa, and one each from Tunisia, Tanzania and Kenya.
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In the spring of the year 73, thousands of Roman soldiers raided Masada, a fortress on top of a cliff in the Judean Desert. For seven years, the Jews had tried, unsuccessfully, to split from the Roman empire, and Masada was the last holdout. According to the ancient historian Josephus, when the Romans breached Masada’s walls, they found 960 dead bodies of Jewish extremists, called Sicarii, who had killed themselves to avoid the inevitable enslavement. Because of Masada’s remote location and harsh, dry climate, nothing much happened to the site for the next 2,000 years, until archaeologists started digging it up in 1963. They found attack ramps and siege towers (some of the best examples we have, apparently, of Roman war technologies), palaces, cisterns, swimming pools, 27 human skeletons and, deep under the rubble, a handful of seeds.
The seeds were stored at room temperature until 2005, when scientists performed radiocarbon dating and identified them as the famed date palm of Judea. (Psalm 92: “The righteous will flourish like a palm tree…They will still bear fruit in old age, they will stay fresh and green.”) The researchers planted the remaining three seeds. One of them grew. When the results were published, in 2008, the plant, nicknamed Methuselah, was more than three feet tall. By this past November, it was more than six feet tall, and healthy enough to be moved out of quarantine and into a park.
No one knows exactly how the seeds managed to survive so long, but it almost certainly had to do with the extremely high temperatures and low humidity of the desert. Methuselah is just one of many examples of organisms that can preserve themselves by shutting down for awhile. In the winter, the wood frog’s heart stops beating and up to 45 percent of its body turns to ice. The tardigrade, a microscopic eight-legged ‘waterbear’, can survive at least 10 years in a cold environment by expelling nearly all of the water from its body.
“Nature is very wise at solving these problems,” says cryobiologist Amir Arav, whose company, Core Dynamics, is based about 85 miles from Masada. For nearly 30 years, Arav has been trying to mimic nature’s preservation feats in the lab. He has frozen rat livers and hearts, and sheep ovaries, and has freeze-dried human sperm, knee cartilage, stem cells and blood.
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As anyone who’s read Shakespeare, seen the Twilight movies or trudged through junior high school knows, there is no social interaction more maddeningly complex than romantic love.
So someone with autism, who presumably lacks the ability to understand others’ thoughts and feelings, couldn’t possibly manage a meaningful relationship. Right?
In fact, many people with autism forge deep romantic relationships, as I learned last month from an engaging New York Times profile of two teenagers with Asperger syndrome.
The couple, Kirsten and Jack, live together and are in love — and they’re not all that unusual, according to the article. There are apparently large online communities devoted to helping people with Asperger syndrome find dates and improve their intimate relationships.
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Head movements taint the results of many brain imaging studies, particularly those analyzing children or individuals with autism. That’s the sobering message from two independent studies published over the past few months in NeuroImage.
Both reports analyze so-called ‘resting-state functional connectivity’ studies: the increasingly popular five-minute brain scans that measure synchrony between different regions when the brain is at rest.
Together, they call into question high-profile findings published in the past couple of years showing that short-range connections in the brain start off strong in children and weaken over the course of typical development, while long-range connections begin weak in children and strengthen over time.
In a study published 14 October, researchers reanalyzed data from several of their own functional connectivity studies after correcting for head motion and found that this maturation pattern usually disappears once head motion is taken into account.
“It really, really, really sucks. My favorite result of the last five years is an artifact,” says lead investigator Steve Petersen, professor of cognitive neuroscience at Washington University in St. Louis.
It’s unclear how many published results head motion has skewed, and whether this changes the bottom-line conclusions. But many researchers are concerned.
“It’s going to impact some findings with regard to the robustness, but whether it completely wipes out the findings that are out there is another question,” says Damien Fair, assistant professor of behavioral neuroscience and psychiatry at Oregon Health and Science University. “It is going to require folks to reanalyze their data, controlling for these new ways of examining motion.”
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