Monthly Archives: January 2009

Gene link to rare cause of baldness

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PARIS ( 2009-01-04 18:57:04 ) :Scientists say they have pinned down a DNA mechanism that gives rise to a rare but distressing form of baldness that strikes before adulthood.

Flaws in a gene called U2HR are to blame for a condition called Maria Unna hereditary hypotrichosis, or MUHH, named after the German trichologist who identified the problem.

Children with MUHH have sparse or no hair at birth, followed by wiry or coarse hair in childhood but progressively lose it at puberty.

Researchers led by Xue Zhang of the Peking Union Medical College in Beijing found that U2HR, located on Chromosome 8, acts as a key switch in the process.

U2HR controls a small peptide — a kind of mini-protein — that in turn affects a previously-identified protein called the human hairless monolog, or HR, which is crucial for the regeneration of hair follicles.

Sifting through the genome of 19 Chinese families with a history of MUHH, the team found mutations of U2HR led to increased levels of HR, the death of hair follicles and thus greater likelihood of this kind of baldness.

The study, published online Sunday in the journal Nature Genetics, offers a potential target for drugs that would block this pathway, offering the hope that youngsters who inherit the mutations will one day keep their hair, say the authors.

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Bugging mosquitoes to fight dengue

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WASHINGTON ( 2009-01-03 01:12:12 ) :Old mosquitoes usually spread disease, so Australian researchers figured out a way to make the pests die younger – naturally, not poisoned.

Scientists have been racing to genetically engineer mosquitoes to become resistant to diseases like malaria and dengue fever that plague millions around the world, as an alternative to mass spraying of insecticides.

A new report on Friday suggested a potentially less complicated approach: Breeding mosquitoes to carry an insect parasite that causes earlier death. Once a mosquito encounters dengue or malaria, it takes two weeks of incubation before the insect can spread that pathogen by biting someone, meaning older mosquitoes are the more dangerous ones.

The Australian experts knew that one type of fruit fly often is infected with a strain of bacterial parasite that cuts its lifespan in half. So they infected the mosquito species that spreads dengue – called Aedes aegypti – with that parasite, breeding several generations in a controlled laboratory.

Voila: Mosquitoes born with the parasite lived only 21 days – even in cozy lab conditions – compared to 50 days for regular mosquitoes, University of Queensland biologist Scott O’Neill reported in the journal Science.

The study funded by American billionaire Bill Gates Mosquitoes tend to die sooner in the wild than in a lab. So if the parasite could spread widely enough among these mosquitoes, it “may provide an inexpensive approach to dengue control”, O’Neill concluded.

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Coral decline warns of ocean changes: Australian scientists

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SYDNEY ( 2009-01-02 12:16:08 ) :A sharp slowdown in coral growth on Australia’s Great Barrier Reef since 1990 is a warning sign that precipitous changes in the world’s oceans may be imminent, scientists said Friday.

Strong evidence points to the cause being a combination of warmer seas and higher acidity from increased levels of atmospheric carbon dioxide, Australian Institute of Marine Science researchers reported.

“The data suggest that this severe and sudden decline in calcification is unprecedented in at least 400 years,” said Glenn De’ath, principal author of a paper published Friday in the international journal Science.

The research shows that corals on the reef have slowed their growth by more than 14 percent since the “tipping point” year of 1990 and on current trends the corals would stop growing altogether by 2050.

“It is cause for extreme concern that such changes are already evident, with the relatively modest climate changes observed to date, in the world’s best protected and managed coral reef ecosystem,” said co-author Janice Lough.

Coral skeletons form the backbone of reef ecosystems and provide the habitat for tens of thousands of plant and animal species and more acidic oceans will affect many sea creatures, not just coral, a statement on the report said.

“All calcifying organisms that are central to the function of marine ecosystems and food webs will be affected, and precipitous changes in the biodiversity and productivity of the world’s oceans may be imminent,” it added.

The findings are based on analyses of annual growth bands — like rings on trees — extending back in time up to 400 years.

Rising sea temperatures are blamed on global warming caused by the build-up in the atmosphere of greenhouse gases such as carbon dioxide — which is also blamed for higher acidity in sea water.

A UN report warned in 2007 that the Great Barrier Reef, described as the world’s largest living organism, could be killed by climate change within decades.

The World Heritage site and major tourist attraction, stretching over more than 345,000 square kilometres (133,000 sq miles) off Australia’s east coast, could become “functionally extinct”, the report said.

The journal Science is published by the American Association for the Advancement of Science.

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New Year’s resolutions can be bad for you: mental health charity

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LONDON ( 2009-01-01 10:54:13 ) :Making self-improvement New Year’s resolutions often leaves people feeling worse, the British mental health charity Mind warned on Thursday.

Mind urged people not to make resolutions focusing on physical imperfections — such as attempting to lose weight — because they create a negative self image and lead to feelings of low self-esteem, hopelessness and even mild depression.

And when such optimistic resolutions fail, that could spark feelings of inadequacy and failure, the charity warned.

“New Year’s resolutions can sometimes focus on our problems or insecurities such as being overweight, feeling unhappy in our jobs or feeling guilty about not devoting enough time to friends and family throughout the year,” said Mind chief executive Paul Farmer.

“We chastise ourselves for our perceived shortcomings and set unrealistic goals to change our behaviour, so it’s not surprising that when we fail to keep resolutions, we end up feeling worse than when we started.

“In 2009, instead of making a New Year’s resolution, think positively about the year to come and what you can achieve.”

Mind suggested resolution-makers focus instead on being active, connecting with nature, learning something new and working for one’s community.

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Deep thinking can make you fat

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LONDON ( 2009-01-01 02:55:11 ) :Researchers at the University Laval in Quebec, Canada, have concluded that too much thinking can make you fat.

According to Jean-Philippe Chaput, the study’s main author, students who participated in the research consumed 23.6 per cent more calories after intellectual tasks.

The research team, supervised by Dr Angelo Tremblay, measured the spontaneous food intake of 14 students after each of three tasks. The first was relaxing in a sitting position, the second reading and summarizing a text, and finally completing a series of memory, attention, and vigilance tests on the computer. After 45 minutes at each activity, participants were invited to eat as much as they wanted from a buffet. The researchers had already discovered that each session of intellectual work requires only three calories more than the rest period.

However, despite the low energy cost of mental work, the students spontaneously consumed 203 more calories after summarizing a text and 253 more calories after the computer tests. This represents a 23.6 per cent and 29.4 per cent increase, respectively, compared with the rest period.

Blood samples taken before, during, and after each session revealed that intellectual work causes much bigger fluctuations in glucose and insulin levels than rest periods. “These fluctuations may be caused by the stress of intellectual work, or also reflect a biological adaptation during glucose combustion,” claimed Chaput.

Chaput added: “Caloric overcompensation following intellectual work, combined with the fact we are less physically active when doing intellectual tasks, could contribute to the obesity epidemic currently observed in industrialized countries.

“This is a factor that should not be ignored, considering that more and more people hold jobs of an intellectual nature.”

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