Rapid evolution of novel forms: Environmental change triggers inborn capacity for adaptation

In the classical view of evolution, species experience spontaneous genetic mutations that produce various novel traits - some helpful, some detrimental. Nature then selects for those most beneficial, passing them along to subsequent generations.It's an elegant model. It's also an extremely time-consuming process likely to fail organisms needing to cope with sudden, potentially life-threatening changes in their environments. Surely some other mechanism could enable more rapid adaptive response.

Using air transportation data to predict pandemics

Computational work conducted at Northwestern University has led to a new mathematical theory for understanding the global spread of epidemics. The resulting insights could not only help identify an outbreak's origin but could also significantly improve the ability to forecast the global pathways through which a disease might spread.

Opportunities to strengthen trauma systems offered by Affordable Care Act

Traumatic injuries are the leading cause of death and disability for people under the age of 45 and the fourth-leading cause of death for people of all ages. Much progress has been made over the last 50 years in developing statewide regionalized trauma systems to care for these injuries, but authors of a review appearing in the December issue of Health Affairs, believe more work is needed to ensure the right patient gets to the right place at the right time, and that the Affordable Care Act may offer opportunities to strengthen trauma systems.

Diabetic macular edema: 'not enough awareness and patient care'

Individuals with diabetes have a significantly higher risk of developing diabetic eye disease. But new research reveals that less than 50% of US adults with diabetic macular edema - retina swelling that can lead to blindness - are told by their doctor that diabetes is the cause of their condition, and less than 60% have had a dilated eye exam in the last year.

This is according to a study published in the journal JAMA Ophthalmology.

Diabetic macular edema (DME) is a form of diabetic retinopathy - the leading cause of blindness in diabetics.

DME occurs when the blood vessels in the eye's macula - a part of the retina responsible for sharp vision - leak fluid and swell. This can lead to partial vision loss or total blindness.

Prompt treatment of the condition can prevent blindness. But in order to catch the condition early, diabetic patients need to undergo regular dilated eye examinations.

To determine the awareness of eye care and eye disease among diabetic patients, a team of researchers, led by Dr. Neil M. Bressler of The Johns Hopkins University School of Medicine and Hospital and editor of JAMA Ophthalmology, analyzed 798 participants from the National Health and Nutrition Examination Survey, who had self-reported diabetes.

Of these, 238 had diabetic retinopathy without DME, while 48 had DME.

Diabetics 'not receiving prompt eye care'

Results of the study revealed that only 44.7% of those with DME said they had been told by their doctor that their eyes had been affected by diabetes, or that they had diabetic retinopathy.

Furthermore, only 46.7% of diabetic individuals with DME said they visited a diabetes nurse educator, dietician or nutritionist for their diabetes more than 1 year ago or never, while only 59.7% said they had a dilated eye exam within the past year.

Commenting on their findings, the researchers say:

"Our results suggest that many individuals with DME report not receiving prompt diabetes-related or eye-related care, although many of these individuals are at risk of substantial visual loss that could be lessened or eliminated with appropriate care."

Importance of dilated eye exams

This is not the only study to find that diabetic patients lack awareness when it comes to their risk of diabetic eye disease and the importance of regular dilated eye examinations.

A recent survey from Diabetic Connect - a social networking site for diabetes sufferers and their families - found that 25% of people with diabetes do not have the recommended annual dilated eye exam.

Walking 2,000 more steps each day reduces cardiovascular risk

People with impaired glucose tolerance can reduce their risk of cardiovascular disease by 8% simply by walking an additional 2,000 steps a day, a large international study says.

Impaired glucose tolerance (IGT), a precursor to type 2 diabetes, affects 79 million Americans, according to the Centers for Disease Control and Prevention (CDC).

Worldwide, the figures are even more staggering - with researchers saying 344 million people are currently affected, and this number is set to rise to 472 million by 2030.

Led by Dr. Thomas Yates, from the University of Leicester in the UK, the latest study analyzed data collected from 9,306 adults from 40 countries.

The findings, published in The Lancet, suggest that an extra 20 minutes of moderate exercise, such as walking, reduces the risk of heart attack and stroke by 8%.

Dr. Yates explains:

"People with IGT have a greatly increased risk of cardiovascular disease. While several studies have suggested that physical activity is beneficially linked to health in those with IGT, this is the first study to specifically quantify the extent to which change in walking behaviour can modify the risk of heart disease, stroke, and cardiovascular-related deaths."

Study confirms narcolepsy as an autoimmune disease

A new study that offers some of the most compelling evidence to date for the idea of "mimicry," where the immune system attacks a body protein because of its similarity to a pathogen protein, confirms that narcolepsy is an autoimmune disease.

Reporting in the latest online issue of Science Translational Medicine, researchers at Stanford University School of Medicine in California show how in genetically susceptible individuals, narcolepsy can be triggered because part of a wakefulness protein, called hypocretin, is very similar to part of a protein from the pandemic 2009 H1N1 "swine flu" virus.

Narcolepsy is a chronic disorder where the brain cannot control sleep-wake cycles, leading to sudden bouts of sleep, often accompanied by cataplexy, an abrupt loss of voluntary muscle tone that can cause collapse.

The National Institutes of Health estimates that narcolepsy affects around 1 in 3,000 Americans. Currently, there is no cure.

Immune system attacks brain cells that make the 'wakefulness' protein

In 2009, Emmanuel Mignot, professor of psychiatry and behavioral sciences at Stanford, who has been working on narcolepsy for over 20 years, led a study that gave the first genetic clue that narcolepsy is an autoimmune disorder where the body's immune system attacks brain cells that make the "wakefulness" protein hypocretin.

Prof. Mignot, who is co-senior author of the new paper, says:

"The relationship between H1N1 infection, vaccination and narcolepsy gave us some very interesting insight into possible causes of the condition. In particular, it strongly suggested to us that T cells of the immune system primed to attack H1N1 can occasionally also cross-react with hypocretin and somehow cause the destruction of hypocretin-producing neurons."

The latest work suggests new ways to interrupt the process before all the hypocretin-producing cells are lost and produce the dramatic symptoms of narcolepsy.

It also opens the prospect of a blood test to diagnose the disease, and it offers new insights into a link between a pandemic H1N1 vaccine used in Europe in 2009 and a spike in narcolepsy cases in Scandinavia the year after.

The team says their work will also give new ideas to researchers investigating other types of autoimmune disorders, particularly those involving the brain.

Co-senior author Elizabeth Mellins, an immunology researcher and professor of pediatrics at Stanford, adds:

"By giving us a new way to think about how neurons in these patients die, it also suggests new therapeutic approaches that we would not have considered if we hadn't learned that this is an autoimmune disease."

Focus on T cells because of link to HLA signature

Previous studies have established that the vast majority of people with narcolepsy have a variant of the human leukocyte antigen (HLA) gene that is found in only a quarter of the general population.

For their work, Prof. Mignot and colleagues decided to focus on the T cells of the immune system because of their association with the HLA signature found in nearly all narcolepsy patients.

HLA is a molecule that sits on the surface of cells that present antigens and bits of proteins they gather from their environment. T cells come along and scan these proteins, and if any of these is "foreign," they start to divide and go around the body looking for it so as to destroy it.

However, if there is a case of mistaken identity on the part of the T cells, then things can go drastically awry. Prof. Mellins explains how they started to suspect this was the case in narcolepsy:

"When we saw that the portion of the hypocretin that seemed to be recognized by the immune system in narcolepsy patients was similar to a part of the pandemic 2009 H1N1 influenza hemagglutinin molecule, we were very hopeful that we were on the right track."

They found that a short, 13-amino-acid section of the H1N1 hemagglutinin protein was very similar to two equally short pieces of the hypocretin protein.

The resemblance was close enough so that the T cells of people who suffer from narcolepsy reacted strongly to the hypocretin protein segments.

The researchers tested this by presenting the small piece of the H1N1 protein to cultured T cells from narcolepsy patients, and saw how this increased the proportion of hypocretin-reactive cells.

Other pathogens may cause similar confusion in immune system

The team was also surprised to find hypocretin cross-reactive T cells in blood taken from narcolepsy patients before H1N1 began circulating in humans in 2009.

Prof. Mignot says this suggests other viruses or pathogens may sometimes cause a similar confusion in the immune system, adding that:

"Indeed, there is a growing appreciation that cross-reactivity of immune T cell recognition may not be as uncommon as once thought. Although this cross-reactivity may make the immune system more adaptable to new infections, it may also increase the chance of mistakes that could result in autoimmune diseases."

In another study published earlier this year, researchers at the UCLA Center for Sleep Research offer another clue to the cause of narcolepsy in humans. They suggest an excess of histamine brain cells may reduce hypocretin cells.

Written by Catharine Paddock PhD

IVF success could double with new way of detecting faulty egg cells

In a study that could change the prospects for the 1 in 15 infertile couples worldwide, researchers in China and the US show how their way of finding genetic defects in egg cells could double the success rate of the reproductive treatment in vitro fertilization.

The new method, based on whole-genome sequencing of individual egg cells, could lead to an accurate, safe and cheap way to select genetically normal embryos for in vitro fertilization (IVF), thus increasing the chances of producing a healthy baby.

As well as looking for DNA sequence variations associated with known genetic disorders, the new approach detects chromosome abnormalities.

Study author Jie Qiao, department director and professor of Gynecology and Obstetrics, Peking University, 3rd Hospital, says:

"In this way, we kill two birds with one stone: one set of deep sequencing analysis to avoid two types of genetic problems."

"Theoretically, if this works perfectly, we will be able to double the success rate of test tube baby technology from 30% to 60% or even more."

The researchers write about their work in a recent online issue of the journal Cell.

New approach sequences whole genome of 'polar bodies'

In IVF, an egg from the woman is fertilized with sperm from the man in a "test tube," and the embryos are then implanted in the woman's uterus.

There are several ways to screen the embryos for genetic defects before implantation, but these carry risks because they involve removing cells from the embryo. Also, they do not detect chromosome abnormalities and genetic disorders based on DNA sequence variations at the same time.

Although whole-genome sequencing has recently been developed for screening sperm cells, until now there was not an equivalent way to apply it egg cells, despite the fact they are more likely to contain chromosome abnormalities.

In their study, the researchers developed a way of sequencing the whole of the genetic code of "polar bodies" - cells that emerge when egg cells divide but then die off, so they can be safely removed without harming the embryo.

Co-author Sunney Xie, Mallinckrodt Professor of Chemistry and Chemical Biology at Harvard University in the US, and also of Peking University, says they are now starting to test their new approach in clinical trials, and:

"If the clinical trial works, this technique could enormously increase the success rate of IVF, especially for older women or women who have had recurrent miscarriages."

In another study published earlier this year, researchers showed an IVF technique that increased pregnancy rates by 20%. The procedure, known as endometrial scratching, improved both pregnancy and birth rates when performed once in women undergoing reproductive treatment.

Written by Catharine Paddock PhD