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Showing posts with label National Institutes of Health. Show all posts
Showing posts with label National Institutes of Health. Show all posts

Wednesday, December 14, 2011

Autistic brains are heavier, with more neurons: study

Posted: 09 November 2011

WASHINGTON: A post-mortem analysis of half a dozen autistic boys showed that their brains were heavier and contained many more neurons than counterparts without the disorder, US researchers said Tuesday.

The study, while small, suggests that brain overgrowth may be occurring in the womb, according to the findings published in the November 9 issue of the Journal of the American Medical Association.

Researchers examined the brains of seven autistic boys, age two to 16, most of whom had died by drowning. The 16-year-old's cause of death was undetermined and one eight-year-old died of muscle cancer.

When they compared them to a control group of six boys without autism who died in accidents, they found that the brains of autistic boys had 67 percent more neurons in the prefrontal cortex and were nearly 18 percent heavier than normal brain weight for age.

"Because cortical neurons are not generated in postnatal life, this pathological increase in neuron numbers in autistic children indicates prenatal causes," the study said.

The researchers suggested that "faulty prenatal cell birth or maintenance may be involved in the development of autism."

The prefrontal cortex is where language and communication is based, as well as behaviors such as mood, attention, and social ability. Typically, autistic children have difficulty in these areas.

However, more research is needed to confirm the link, and to determine if and how brain differences may be tied to the severity of an autistic person's symptoms.

"Factors that normally organize the brain appear to be disrupted," said an accompanying editorial by Janet Lainhart of the University of Utah and Nicholas Lange of the Harvard University Schools of Medicine and Public Health.

Previous studies have suggested that clinical signs of autism tend to coincide with a period of abnormal brain and head growth that usually becomes apparent at nine to 18 months of age, according to the article.

Autism includes a wide spectrum of developmental differences and may range from mild social awkwardness to complete inability to communicate, repetitive movements, sensitivity to certain lights and sounds, and behavioral problems.

As many as one in 110 children is diagnosed with autism. The disorder is three to four times more common in boys than in girls, according to the advocacy group Autism Speaks which helped fund the study.

Other funding came from Cure Autism Now, The Emch Foundation, the Simons Foundation, the Thursday Club Juniors, and the University of California San Diego - National Institutes of Health Autism Center of Excellence.

-AFP/pn



Taken from ChannelNewsAsia.com; source article is below:
Autistic brains are heavier, with more neurons: study

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Thursday, July 28, 2011

Mosquitoes are suckered in new malaria research

Just make sure you don't get bitten, not by insects, not by animals, nor even humans! But would you carry dirty clothes?
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Posted: 02 June 2011

A mosquito is bloated with blood as it inserts its stinger into human flesh (AFP/USDA-HO/File)
PARIS - In the biggest lab breakthrough against malaria in years, scientists on Wednesday said they had identified odour molecules that baffle blood-thirsty mosquitoes.

The molecules disrupt carbon-dioxide sensors that alert mosquitoes to exhaled breath, which signals the presence of a human nearby, the team reported.

The work could lead to revolutionary but low-cost chemicals to confuse, deter or trap mosquitoes, it said.

They could be invaluable in poor tropical countries, providing an alternative to DEET, a skin repellent that is expensive, needs repeat applications and is showing worrying signs of resistance.

"These chemicals offer powerful advantages as potential tools for reducing mosquito-human contact and can lead to the development of new generations of insect repellents and lures," said Anandasankar Ray, an assistant professor of entomology at the University of California at Riverside, who led the study.

Traps for mosquitoes already exist, in the form of dry ice, gas cylinders of carbon dioxide or propane combustion.

But these gadgets are too bulky and far too expensive to be used for mosquito control, especially in poor settings.

Future mosquito traps, Ray predicted, could be "highly portable, convenient and easily replenishable."

Malaria claimed 781,000 lives in 2009, according to the UN's World Health Organisation (WHO), which is heading efforts to distribute insecticide-treated mosquito nets and to spray reproduction sites.

About 90 percent of malaria deaths each year occur in Africa and 92 percent of those are children aged under five.

Other mosquito-borne diseases are dengue, which sickens around 50 million people each year, yellow fever, filariasis and West Nile virus.

Building on research on fruitflies, a common laboratory tool, Ray's team looked at three of mosquito species whose females are disease vectors: Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus.

The odour molecules that they identified disrupt receptor cells for carbon dioxide located in tiny, antennae-like appendages close to the mosquito's mouth.

These receptors are activated by a whiff of carbon dioxide, triggering a signal in the brain that prompts the insect to fly upwind, following the puffs of CO2 until they reach its source. Mosquito also use heat sensors and sight to home in on their meal.

The findings have been tested in a small-scale experiment in Kenya, using huts where alluring plumes of CO2 were released to attract mosquitoes and odour molecules were released to bamboozle them.

Mark Stopfer, a specialist at the US National Institutes of Health (NIH), said the results opened up "a promising line of defence."

He added some words of caution, saying that mosquitoes were attracted to other odours in human sweat and skin. In addition, the chemicals that have been tested on insects so far have not yet been tested for safety on humans, he noted.

-AFP/rt



Taken from ChannelNewsAsia.com; source article is below:
Mosquitoes are suckered in new malaria research

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