Sunday, January 20, 2013

'Quadruple helix' DNA seen in human cells


'Quadruple helix' DNA seen in human cells


A representation of the four-stranded structure (L) and fluorescent markers reveal its presence inside cells (R) A representation of the four-stranded structure (L) with fluorescent markers revealing its presence inside cells (R)

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Cambridge University scientists say they have seen four-stranded DNA at work in human cells for the first time.
The famous "molecule of life", which carries our genetic code, is more familiar to us as a double helix.
But researchers tell the journal Nature Chemistry that the "quadruple helix" is also present in our cells, and often in functions related to cancer.
They suggest that control of the structures could provide novel ways to fight the disease.
"The existence of these structures may be loaded when the cell has a certain genotype or a certain dysfunctional state," said Prof Shankar Balasubramanian from Cambridge's department of chemistry.
"We need to prove that; but if that is the case, targeting them with synthetic molecules could be an interesting way of selectively targeting those cells that have this dysfunction," he told BBC News.
Tag and track It will be exactly 60 years ago in February that James Watson and Francis Crick famously burst into the pub next to their Cambridge laboratory to announce the discovery of the "secret of life".
What they had actually done was describe the way in which two long chemical chains wound up around each other to encode the information cells need to build and maintain our bodies.
Today, the pair's modern counterparts in the university city continue to work on DNA's complexities.
Balasubramanian's group has been pursuing a four-stranded version of the molecule that scientists have produced in the test tube now for a number of years.
It is called the G-quadruplex. The "G" refers to guanine, one of the four chemical groups, or "bases", that hold DNA together and which encode our genetic information (the others being adenine, cytosine, and thymine).
The G-quadruplex seems to form in DNA where guanine exists in substantial quantities.
And although ciliates, relatively simply microscopic organisms, have displayed evidence for the incidence of such DNA, the new research is said to be the first to firmly pinpoint the quadruple helix in human cells.
'Funny target' The team, led by Giulia Biffi, a researcher in Balasubramaninan's lab, produced antibody proteins that were designed specifically to track down and bind to regions of human DNA that were rich in the quadruplex structure. The antibodies were tagged with a fluorescence marker so that the time and place of the structures' emergence in the cell cycle could be noted and imaged.
This revealed the four-stranded DNA arose most frequently during the so-called "s-phase" when a cell copies its DNA just prior to dividing.
Prof Balasubramaninan said that was of key interest in the study of cancers, which were usually driven by genes, or oncogenes, that had mutated to increase DNA replication.
If the G-quadruplex could be implicated firmly in the development of some cancers, it might be possible, he said, to make synthetic molecules that contained the structure and blocked the runaway cell proliferation at the root of tumours.
"We've come a long way in 10 years, from simple ideas to really seeing some substance in the existence and tractability of targeting these funny structures," he told the BBC.
"I'm hoping now that the pharmaceutical companies will bring this on to their radar and we can perhaps take a more serious look at whether quadruplexes are indeed therapeutically viable targets."
Prof Shankar Balasubramanian Prof Shankar Balasubramanian in front of a painting by artist Annie Newman that represents quadruplex DNA

Saturday, January 5, 2013

Immune system 'booster' may hit cancer


Immune system 'booster' may hit cancer

Two T-cells on the surface of a cancerous cell Two white blood cells attacking a cancer

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Vast numbers of cells that can attack cancer and HIV have been grown in the lab, and could potentially be used to fight disease.
The cells naturally occur in small numbers, but it is hoped injecting huge quantities back into a patient could turbo-charge the immune system.
The Japanese research is published in the journal Cell Stem Cell.
Experts said the results had exciting potential, but any therapy would need to be shown to be safe.
The researchers concentrated on a type of white blood cell known as a cytotoxic T-cell, which can recognise telltale markings of infection or cancer on the surfaces of cells. If a marking is recognised, it launches an attack.
Teams at the University of Tokyo and the Riken Research Centre for Allergy and Immunology used advances in stem cell technology to make more T-cells.
One group extracted T-cells which targeted a patient's skin cancer. Another group did the same for HIV.

“Start Quote

The next step will be to test whether these T-cells can selectively kill tumour cells, but not other cells in the body”
Dr Hiroshi Kawamoto Researcher
These T-cells were converted into stem cells, which could dramatically increase in number when grown in the laboratory. These were converted back into T-cells which should also have the ability to target the cancer or HIV.
New weapon? The groups have proved only that they can make these cells, not that they can be safely put back into patients or that if would make a difference to their disease if they did.
Dr Hiroshi Kawamoto, who worked on the cancer immune cells at Riken, said: "The next step will be to test whether these T-cells can selectively kill tumour cells, but not other cells in the body.
"If they do, these cells might be directly injected into patients for therapy. This could be realized in the not-so-distant future."
Dr Hiromitsu Nakauchi from the University of Tokyo said it was "unclear" whether this technique would help in treating HIV and that other infections and cancer may be a better place to start.
'Very exciting' Experts in the field said the findings were encouraging.
Prof Alan Clarke, the director of the European Cancer Stem Cell Research Institute at Cardiff University, said: "This is a potentially very exciting development which extends our capacity to develop novel cell therapies."
He said it was important that cells could be tailored for each patient so there would be no risk of rejection.
Other experts said the findings were still at an early stage, but were still very promising and represented a strong foundation for future research. However, Cancer Research UK said it was still too early to know if any therapy would be safe.
Prof Sir John Burn, from the Institute of Genetic Medicine at Newcastle University, said: "This is a very appealing concept and the research team are to be congratulated on demonstrating the feasibility of expanding these killer cells.
However he added: "Even if these T cells are effective, it could prove very challenging to produce large quantities safely and economically.
"Nevertheless, there is real promise of this becoming an alternative when conventional therapies have failed."

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Totally blind mice get sight back


Totally blind mice get sight back

Eye

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Totally blind mice have had their sight restored by injections of light-sensing cells into the eye, UK researchers report.
The team in Oxford said their studies closely resemble the treatments that would be needed in people with degenerative eye disease.
Similar results have already been achieved with night-blind mice.
Experts said the field was advancing rapidly, but there were still questions about the quality of vision restored.
Patients with retinitis pigmentosa gradually lose light-sensing cells from the retina and can become blind.

“Start Quote

It's the first proof that you can take a completely blind mouse, put the cells in and reconstruct the entire light-sensitive layer”
Prof Robert MacLaren University of Oxford
The research team, at the University of Oxford, used mice with a complete lack of light-sensing photoreceptor cells in their retinas. The mice were unable to tell the difference between light and dark.
Reconstruction They injected "precursor" cells which will develop into the building blocks of a retina once inside the eye. Two weeks after the injections a retina had formed, according to the findings presented in the Proceedings of the National Academy of Sciences journal.
Prof Robert MacLaren said: "We have recreated the whole structure, basically it's the first proof that you can take a completely blind mouse, put the cells in and reconstruct the entire light-sensitive layer."
Previous studies have achieved similar results with mice that had a partially degenerated retina. Prof MacLaren said this was like "restoring a whole computer screen rather than repairing individual pixels".
The mice were tested to see if they fled being in a bright area, if their pupils constricted in response to light and had their brain scanned to see if visual information was being processed by the mind.
Vision Prof Pete Coffee, from the Institute of Ophthalmology at University College London, said the findings were important as they looked at the "most clinically relevant and severe case" of blindness.

“Start Quote

This is probably what you would need to do to restore sight in a patient that has lost their vision”
Prof Pete Coffee University College London
"This is probably what you would need to do to restore sight in a patient that has lost their vision," he said.
However, he said this and similar studies needed to show how good the recovered vision was as brain scans and tests of light sensitivity were not enough.
He said: "Can they tell the difference between a nasty animal and something to eat?"
Prof Robin Ali published research in the journal Nature showing that transplanting cells could restore vision in night-blind mice and then showed the same technique worked in a range of mice with degenerated retinas.
He said: "These papers demonstrate that it is possible to transplant photoreceptor cells into a range of mice even with a severe level of degeneration.
"I think it's great that another group is showing the utility of photoreceptor transplantation."
Researchers are already trialling human embryonic stem cells, at Moorfields Eye Hospital, in patients with Stargardt's disease. Early results suggest the technique is safe but reliable results will take several years.
Retinal chips or bionic eyes are also being trailed in patients with retinitis pigmentosa.

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Friday, January 4, 2013

Does confidence really breed success? - No


Does confidence really breed success?

A composite image showing (clockwise):  A woman powdering her face, a woman applying red lipstick, a woman looking at her own reflection in a window, a man pulling his muscles and a man wearing sunglasses with his collar turned up. All images THINKSTOCK
Research suggests that more and more American university students think they are something special. High self-esteem is generally regarded as a good thing - but could too much of it actually make you less successful?
About nine million young people have filled out the American Freshman Survey, since it began in 1966.
It asks students to rate how they measure up to their peers in a number of basic skills areas - and over the past four decades, there has been a dramatic rise in the number of students who describe themselves as being "above average" for academic ability, drive to achieve, mathematical ability and self-confidence.
This was revealed in a new analysis of the survey data, by US psychologist Jean Twenge and colleagues.
Graphic showing how the the percentage of American students rating themselves as "above average" has gone up. Measures shown: Drive to achieve, social self-confidence, intellectual self-confidence, leadership ability and writing ability
Self-appraisals of traits that are less individualistic - such as co-operativeness, understanding others and spirituality - saw little change, or a decrease, over the same period.

Self-esteem and confidence

Psychologists rarely use the word confidence. They have separate measures for:
  • self-esteem - the value people place on themselves
  • narcissism - definitions vary, but essentially a negative, destructive form of high self-esteem
  • self-efficacy - the ability to achieve personal goals
Twenge adds that while the Freshman Survey shows that students are increasingly likely to label themselves as gifted in writing ability, objective test scores indicate that actual writing ability has gone down since the 1960s.
And while in the late 1980s, almost half of students said they studied for six or more hours a week, the figure was little over a third by 2009 - a fact that sits rather oddly, given there has been a rise in students' self-proclaimed drive to succeed during the same period.
Another study by Twenge suggested there has been a 30% tilt towards narcissistic attitudes in US students since 1979.
The Oxford English Dictionary defines narcissism as: "Excessive self-love or vanity; self-admiration, self-centredness."
"Our culture used to encourage modesty and humility and not bragging about yourself," says Twenge. "It was considered a bad thing to be seen as conceited or full of yourself."

The Freshman Survey

Three female students
  • A nationally representative sample of first-year college and university students in the US
  • Conducted every year since 1966
  • Questions on a range of topics - including values, financial situation, and expectations of college
Not everyone with high self-esteem is a narcissist. Some positive views of the self may be harmless and in fact quite justified.
But one in four recent students responded to a questionnaire, the Narcissistic Personality Inventory, in a way which leaned towards narcissistic views of the self.
Though some have argued that narcissism is an essential trait, Twenge and her colleagues see it as negative and destructive.
In The Narcissism Epidemic, co-written with Keith Campbell, Twenge blames the growth of narcissistic attitudes on a range of trends - including parenting styles, celebrity culture, social media and access to easy credit, which allows people to appear more successful than they are.
"What's really become prevalent over the last two decades is the idea that being highly self-confident - loving yourself, believing in yourself - is the key to success.
"Now the interesting thing about that belief is it's widely held, it's very deeply held, and it's also untrue."

Find out more

This bewitching idea - that people's lives will improve with their self-esteem - led to what came to be known as The Self-Esteem Movement.
Legions of self-help books have propagated the idea that we each have it within us to achieve great things - we just need to be more confident.
Over 15,000 journal articles have examined the links between high self-esteem and measurable outcomes in real life, such as educational achievement, job opportunities, popularity, health, happiness and adherence to laws and social codes.
Yet there is very little evidence that raising self-esteem leads to tangible, positive outcomes.
"If there is any effect at all, it is quite small," says Roy Baumeister of Florida State University. He was the lead author of a 2003 paper that scrutinised dozens of self-esteem studies.

All about me, me, me...

  • In a recent paper Jean Twenge examined changes in pronoun use in American books published between 1960 and 2008, using the Google Books ngram database
  • She found that first person plural pronouns (we, us our etc.) decreased in use by 10% while first person singular pronouns (I, me, my etc.) increased in use by 42%
He found that although high self-esteem frequently had a positive correlation with success, the direction of causation was often unclear. For example, are high marks awarded to people with high self-esteem or does getting high marks engender high self-esteem?
And a third variable can influence both self-esteem and the positive outcome.
"Coming from a good family might lead to both high self-esteem and personal success," says Baumeister.
"Self-control is much more powerful and well-supported as a cause of personal success. Despite my years invested in research on self-esteem, I reluctantly advise people to forget about it."

Am I a narcissist?

Close-up of a woman wearing red lipstick
The Narcissistic Personality Inventory asks 40 questions, then ranks you on a narcissism scale
This doesn't mean that under-confident people will be more successful in school, in their careers or in sport.
"You need to believe that you can go out and do something but that's not the same as thinking that you're great," says Twenge. She gives the example of a swimmer attempting to learn a turn - this person needs to believe that they can acquire that skill, but a belief that they are already a great swimmer does not help.
Forsyth and Kerr studied the effect of positive feedback on university students who had received low grades (C, D, E and F). They found that the weaker students actually performed worse if they received encouragement aimed at boosting their self-worth.
"An intervention that encourages [students] to feel good about themselves, regardless of work, may remove the reason to work hard," writes Baumeister.
So do young people think they are better than they are?
If they are, perhaps the appropriate response is not condemnation but pity.
The narcissists described by Twenge and Campbell are often outwardly charming and charismatic. They find it easy to start relationships and have more confidence socially and in job interviews. Yet their prognosis is not good.

How self-esteem become a movement

Werner Erhard
  • The Self-Esteem Movement is said to have its roots in the civil rights movement, which promoted group solidarity - but also the rights of individuals to be who they want
  • A series of seminars were held in the 1960s on achieving happiness and fulfilment by tapping inner potential - it was called The Human Potential Movement
  • First popular book on self-esteem published in 1969 - The Psychology of Self-Esteem by psychologist Nathaniel Branden
  • Werner Erhard (above) held sessions aimed at boosting self-esteem in US prisons in the 1970s - there were similar programmes in the 1980s to try to reduce teen pregnancy rates and crime
  • Interest is still high - there were more than 40,000 articles about self-esteem in newspapers and magazines between 2002 and 2007
"In the long-term, what tends to happen is that narcissistic people mess up their relationships, at home and at work," says Twenge.
Narcissists may say all the right things but their actions eventually reveal them to be self-serving.
As for the narcissists themselves, it often not until middle age that they notice their life has been marked by an unusual number of failed relationships.
But it's not something that is easy to fix - narcissists are notorious for dropping out of therapy.
"It's a personality trait," says Twenge. "It's by definition very difficult to change. It's rooted in genetics and early environment and culture and things that aren't all that malleable."
Things also don't look good for the many young people who - although not classed as narcissists - have a disproportionately positive self-view.
A 2006 study led by John Reynolds of Florida State University found that students are increasingly ambitious, but also increasingly unrealistic in their expectations, creating what he calls "ambition inflation".
"Since the 1960s and 1970s, when those expectations started to grow, there's been an increase in anxiety and depression," says Twenge.
"There's going to be a lot more people who don't reach their goals."
Jean Twenge spoke to Health Check on the BBC World Service. You can listen to the programme or download the Health Check podcast.

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Monday, December 31, 2012

Homelessness Abolished in Scotland!


New rights for the homeless come into force


The deputy first minister called it a "landmark" day in the fight against homelessness

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Legislation which aims to effectively end homelessness in Scotland has come into force.
The change entitles anyone finding themselves homeless through no fault of their own to settled accommodation.
Previously, only those classed as being in priority need - often families with children - had that right.
It meets Scotland's historic 2012 homelessness commitment, first set 10 years ago by the Labour/Lib Dem government.
The change, passed unanimously last month under the Homelessness (Abolition of Priority Need Test) (Scotland) Order 2012, will give an estimated 3,000 more people a year the right to settled accommodation.
As the changes came into force, the deputy first minister also announced £300,000 would be spent over the next two years to help councils with their efforts to prevent homelessness.
'Heartache and trauma' Nicola Sturgeon said: "This is a landmark day in the fight against homelessness.
"I know the heartache and trauma of homelessness from working closely with households faced with the prospect of losing the roof over their head.
"Meeting our 2012 commitment guarantees that those who lose their home from no fault of their own will be guaranteed settled accommodation.
"It is absolutely right to offer this guarantee in a time of crisis for people. It sends the signal that we are there to help, there is hope and that the state will do what it can."
Official figures from February 2012 suggested the number of homeless people in Scotland is at its lowest for a decade.
Graeme Brown, director of the housing and homelessness charity Shelter Scotland, said: "Scotland can be very proud that it is making history by meeting the 2012 commitment - which is internationally regarded as the cutting edge of progressive homelessness reform.
"I congratulate all the local authorities who have made widespread changes in order to meet their new responsibilities to homeless people."

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Monday, December 3, 2012

Plastic bulb development promises better quality light


Plastic bulb development promises better quality light

Wake forest university researchers

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US researchers say they have developed a new type of lighting that could replace fluorescent bulbs.
The new source is made from layers of plastic and is said to be more efficient while producing a better quality of flicker-free light.
The scientists behind it say they believe the first units will be produced in 2013.
Details of the new development have been published in the journal Organic Electronics.

“Start Quote

What we've found is a way of creating light rather than heat”
Prof David Carroll Wake Forest University
Brighter white
The new light source is called field-induced polymer electroluminescent (Fipel) technology. It is made from three layers of white-emitting polymer that contain a small volume of nanomaterials that glow when electric current is passed through them.
The inventor of the device is Dr David Carroll, professor of physics at Wake Forest University in North Carolina. He says the new plastic lighting source can be made into any shape, and it produces a better quality of light than compact fluorescent bulbs which have become very popular in recent years.
Wake university researcher with light The new light source is said to be twice as efficient as fluorescent bulbs
"They have a bluish, harsh tint to them, " he told BBC News, "it is not really accommodating to the human eye; people complain of headaches and the reason is the spectral content of that light doesn't match the Sun - our device can match the solar spectrum perfectly.
"I'm saying we are brighter than one of these curly cube bulbs and I can give you any tint to that white light that you want."

Lighting up the world

  • Lighting accounts for around 19% of global electricity use
  • A worldwide switch to low-energy bulbs could save the output of around 600 power plants
There have been several attempts to develop new light-bulbs in recent years - Light Emitting Diodes (LEDs) have come a long way since they were best known for being indicator lights in electronic devices. Over the past decade, they have become much more widely used as a light source as they are both bright and efficient. They are now often used on large buildings.
Light not heat Another step forward has been organic LEDs (OLEDs) which also promise greater efficiency and better light than older, incandescent bulbs. Their big advantage over LEDs is that they can be transformed into many different shapes including the screens for high-definition televisions.
But Prof Carroll believes OLED lights haven't lived up to the hype.
"They don't last very long and they're not very bright," he said. "There's a limit to how much brightness you can get out of them. If you run too much current through them they melt."
The Fipel bulb, he says, overcomes all these problems.
"What we've found is a way of creating light rather than heat. Our devices contain no mercury, they contain no caustic chemicals and they don't break as they are not made of glass."
Prof Carroll says his new bulb is cheap to make and he has a "corporate partner" interested in manufacturing the device. He believes the first production runs will take place in 2013.
He also has great faith in the ability of the new bulbs to last. He says he has one in his lab that has been working for about a decade.

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Friday, November 30, 2012

Bread that lasts for 60 days could cut food waste


Bread that lasts for 60 days could cut food waste


Bread

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An American company has developed a technique that it says can make bread stay mould-free for 60 days.
The bread is zapped in a sophisticated microwave array which kills the spores that cause the problem.
The company claims it could significantly reduce the amount of wasted bread - in the UK alone, almost a third of loaves purchased.
The technique can also be used with a wide range of foods including fresh turkey and many fruits and vegetables.
World of waste Food waste is a massive problem in most developed countries. In the US, figures released this year suggest that the average American family throws away 40% of the food they purchase - which adds up to $165bn (£102bn) annually.
Bread is a major culprit, with 32% of loaves purchased in the UK thrown out as waste when they could be eaten, according to figures from the Department for Environment, Food and Rural Affairs (Defra).
Machine microwave The machine uses similar technology to a home microwave
One of the biggest threats to bread is mould. As loaves are usually wrapped in plastic, any water in the bread that evaporates from within is trapped and makes the surface moist. This provides excellent growing conditions for Rhizopus stolonifer, the fungus that leads to mould.
In normal conditions, bread will go mouldy in around 10 days.
But an American company called Microzap says it has developed a technique that will keep the bread mould free for two months.
At its laboratory on the campus of Texas Tech University in Lubbock, chief executive Don Stull showed off the long, metallic microwave device that resembles an industrial production line. Originally designed to kill bacteria such as MRSA and salmonella, the researchers discovered it could kill the mould spores in bread in around 10 seconds.
"We treated a slice of bread in the device, we then checked the mould that was in that bread over time against a control, " he explained.
"And at 60 days it had the same mould content as it had when it came out of the oven."
Question of taste The machine the team has built uses much the same technology as found in commercial microwaves - but with some important differences, according to Mr Stull.
"We introduce the microwave frequencies in different ways, through a slotted radiator. We get a basically homogeneous signal density in our chamber - in other words, we don't get the hot and cold spots you get in your home microwave."

20th-Century history of bread

Bread making competition 1965
  • 1928: First bread slicing machine, invented by Otto Rohwedder, exhibited in US
  • 1930: Large UK bakeries take commercial slicers and sliced bread first appears in shops
  • 1933: About 80% of US bread is pre-sliced and wrapped, and the phrase "the best thing since sliced bread" is coined
  • 1941: Calcium added to UK flour to prevent rickets
  • 1942: The national loaf - much like today's brown loaf - introduced to combat shortage of white flour
  • 1954: Conditions in bakeries regulated by the Night Baking Act
  • 1956: National loaf abolished
  • 1961: The Chorleywood Bread Process introduced
Source: The Federation of Bakers
The company's device has attracted plenty of interest from bread manufacturers - but it is worried that it could push up costs in an industry where margins are very tight.
And there is also a concern that consumers might not take to bread that lasts for so long. Mr Stull acknowledges it might be difficult to convince some people of the benefits.
"We'll have to get some consumer acceptance of that," he said. "Most people do it by feel and if you still have that quality feel they probably will accept it. "
Mr Stull believes that the technology could impact bread in other ways. He said that bread manufacturers added lots of preservatives to try and fight mould, but then must add extra chemicals to mask the taste of the preservatives. If bakers were able to use the microwave technology, they would be able to avoid these additives.
While a wholesale change in the bread industry might be difficult to achieve, there may be more potential with other foods, including ground turkey.
In 2011, food giant Cargill had to recall 16 million kg of the product after a salmonella outbreak. Mr Stull believes that using microwaves would be an effective way of treating this and several other products ranging from jalapenos to pet foods.
The only fruit that his device was unable to treat effectively were cantaloupes.
"We've used our tumbler machine to treat them, he says "but you can't tumble cantaloupes because they damage."

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