ScienceDaily (Oct. 27, 2011) — Huge progress has been made over the last few years in scientific research into progeria, a disease that leads to premature aging in children. In 2003, a team directed by Nicolas Lévy discovered the gene, and, in 2008, 12 children were able to begin clinical trials in which two molecules were combined to slow down the characteristic effects of the disease: premature aging. Researchers are continuing their efforts in an attempt to counter the consequences of the genetic defect that causes progeria.

Until now, no model had been able to accurately imitate the effects of the disease in humans. For several years, research has been conducted in close collaboration from teams led by Nicolas Lévy and Annachiara De Sandre-Giovannoli at Inserm/Université de la Méditerranée and from a team led by Carlos López-Otín (University of Oviedo) and has succeeded in making such a model possible. The lifespan of mice treated through gene therapy is significantly extended and several other parameters related to them are improved. The research, published Oct. 26, 2011 in Science Translational Medicine, received backing from the AFM thanks to donations from a Telethon.

Progeria is a rare genetic disease. Children suffering from it seem to experience accelerated aging (chronic hair loss, joint pains, thin and hairless skin, cardiovascular problems). In 2003, Nicolas Lévy and his team identified the cause of the disease when they discovered the involvement of the LMNA (nuclear protein-coding) gene, lamin A/C. The mutation causes the production of a truncated protein, progerin, which accumulates in the nuclei of cells and its toxic effects cause their deformation and various other malfunctions. It has since been proven that progerin progressively accumulates in normal cells, thus establishing a link between the disease and physiological aging.

In 2008, European clinical trials began on twelve children suffering from progeria. The treatment is based on a combination of two existing molecules: statins (prescribed in the treatment and prevention of atherosclerosis and cardiovascular risks) and aminobisphosphonates (prescribed in to treat osteoporosis and to prevent complications in some forms of cancer). The use of both these molecules aims to chemically alter progerin to reduce its toxicity. However, although this treatment aimed to slow down the development of the disease, it did not reduce the quantities of progerin. To study this aspect, researchers needed to obtain a relevant animal model.

An "authentic" progeria model…

To generate a model of this kind, Spanish and French researchers decided to introduce a gene mutation (G609G), equivalent to that identified in humans (G608G), in mice to reproduce the exact pathological mechanism found in the children, with a view to then blocking it. The mice models were created under the supervision of Bernard Malissen using the IBISA platform located at the Marseille-Luminy Centre of Immunology. This approach made it possible to obtain young mice that produced progerin, characteristic of the disease in humans. After three weeks alive, the mutated mice displayed growth defects, weight loss caused by bone deformation and cardiovascular and metabolic anomalies mirroring the human phenotype and considerably reducing their lifespan (an average of 103 days compared with two years for wild mice). The progerin thus produced accumulates in mouse cells via genetic mechanisms (abnormal splicing) identical to those observed in humans, i.e. the source of anomalies characteristic of the disease.

… for a targeted gene therapy

Using this unique progeria animal model, the researchers focussed their efforts on implementing a mutation-targeted treatment, with a view to reducing, and, if possible, preventing the production of progerin. To this end, they used "vivo-morpholino" antisense oligonucleotide technology. "This technology, explains Nicolas Lévy, is based on introducing a synthetic antisense aglionecleotide into mice. As is the case with progeria, this sequence is applied to block (or facilitate) the production of a functional protein using a gene. In this case, the production of progerin, as well as lamin A from the gene, were reduced."

There was a highly significant increase in life expectancy of mice treated using this new technology, from an average of 155 days to a maximum of 190 days.

Nicolas Levy's team, with continued collaboration with Carlos López-Otín, now intend to translate this preclinical research into a new therapeutic trial for children, possibly combined with other pharmacological molecules. Other research is being conducted in parallel to find alternative administration channels for antisense oligonucleotides.

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The above story is reprinted from materials provided by INSERM (Institut national de la santé et de la recherche médicale).

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Fernando G. Osorio, Claire L. Navarro, Juan Cadiñanos, Isabel C. López-Mejía, Pedro M. Quirós, Catherine Bartoli, José Rivera, Jamal Tazi, Gabriela Guzmán, Ignacio Varela, Danielle Depetris, Félix De Carlos, Juan Cobo, Vicente Andrés, Annachiara De Sandre-Giovannoli, José M. P. Freije, Nicolas Lévy, Carlos López-Otín. Splicing-Directed Therapy in a New Mouse Model of Human Accelerated Aging. Science Translational Medicine, 2011; 3 (106): 106ra107 DOI: 10.1126/scitranslmed.3002847

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ScienceDaily (Oct. 27, 2011) — The mere presence of a predator causes enough stress to kill a dragonfly, even when the predator cannot actually get at its prey to eat it, say biologists at the University of Toronto.

"How prey respond to the fear of being eaten is an important topic in ecology, and we've learned a great deal about how these responses affect predator and prey interactions," says Professor Locke Rowe, chair of the Department of Ecology and Evolutionary Biology (EEB) and co-principal investigator of a study conducted at U of T's Koffler Scientific Reserve.

"As we learn more about how animals respond to stressful conditions -- whether it's the presence of predators or stresses from other natural or human-caused disruptions -- we increasingly find that stress brings a greater risk of death, presumably from things such as infections that normally wouldn't kill them," says Rowe.

Shannon McCauley, a post-doctoral fellow, and EEB professors Marie-Josée Fortin and Rowe raised juvenile dragonfly larvae (Leucorrhinia intacta) in aquariums or tanks along with their predators. The two groups were separated so that while the dragonflies could see and smell their predators, the predators could not actually eat them.

"What we found was unexpected -- more of the dragonflies died when predators shared their habitat," says Rowe. Larvae exposed to predatory fish or aquatic insects had survival rates 2.5 to 4.3 times less than those not exposed.

In a second experiment, 11 per cent of larvae exposed to fish died as they attempted to metamorphose into their adult stage, compared to only two per cent of those growing in a fish-free environment. "We allowed the juvenile dragonflies to go through metamorphosis to become adult dragonflies, and found those that had grown up around predators were more likely to fail to complete metamorphosis successfully, more often dying in the process," says Rowe.

The scientists suggest that their findings could apply to all organisms facing any amount of stress, and that the experiment could be used as a model for future studies on the lethal effects of stress.

The research is described in a paper titled "The deadly effects of 'nonlethal' predators," published in Ecology and highlighted in Nature this week. It was supported by grants to Fortin and Rowe from the Canada Research Chairs program and the Natural Sciences and Engineering Research Council of Canada, and a post-doctoral fellowship awarded to McCauley.

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Shannon J. McCauley, Locke Rowe, Marie-Josée Fortin. The deadly effects of “nonlethal” predators. Ecology, 2011; 92 (11): 2043 DOI: 10.1890/11-0455.1

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ScienceDaily (Oct. 27, 2011) — Publishing in the current issue of The Journal of Biological Chemistry, researchers at Moffitt Cancer Center in Tampa, Fla., have discovered additional mechanisms of "Akt" activation and suggest a component of that activation mechanism -- inhibitor of nuclear factor kappa-B kinase subunit epsilon (IKBKE) -- could be targeted as a therapeutic intervention for treating cancer.

Akt, also known as protein kinase B, is one of about 500 protein kinases in the human genome. Kinases are known to regulate the majority of cellular pathways. Akt modifies other proteins chemically and regulates cell proliferation.

"Recent evidence suggests that IKBKE is an oncogenic kinase that participates in malignant transformation and tumor development," said Moffitt senior researcher and lead author Jin Q. Cheng, Ph.D., M.D. "Our study identified Akt as a bona fide substrate of IKBKE and IKBKE direct activation of Akt independent PI3K and revealed a functional link between IKBKE and Akt activation in breast cancer."

Cheng's lab studies a variety of genetic alterations and their molecular mechanisms in both ovarian and breast cancer, particularly on their effect on the molecules that are regulated by Akt and the small molecule inhibitors of Akt.

"We found that inhibition of Akt suppresses IKBKE's oncogenic transformation," said Cheng. "This is significant because overexpression of IKBKE and activation of Akt has been observed in more than 50 percent of human cancers. Akt inhibitors targeting PH domain do not have inhibitory effect on IKBKE-induced Akt."

The researchers experimented with a variety of inhibitors currently being used in clinical trials.

The laboratory study utilized breast cancer cell lines from received from patient donors at Moffitt and cell lines received from Harvard University and Johns Hopkins University. The work was supported by a National Institutes of Health grant and a grant from the James and Esther King Biomedical Research Program.

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The above story is reprinted from materials provided by H. Lee Moffitt Cancer Center & Research Institute.

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J.-P. Guo, D. Coppola, J. Q. Cheng. IKBKE Protein Activates Akt Independent of Phosphatidylinositol 3-Kinase/PDK1/mTORC2 and the Pleckstrin Homology Domain to Sustain Malignant Transformation. Journal of Biological Chemistry, 2011; 286 (43): 37389 DOI: 10.1074/jbc.M111.287433

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ScienceDaily (Oct. 28, 2011) — Scientists including those from Queen's University have discovered that taking regular aspirin halves the risk of developing hereditary cancers.

Hereditary cancers are those which develop as a result of a gene fault inherited from a parent. Bowel and womb cancers are the most common forms of hereditary cancers. Fifty thousand people in the UK are diagnosed with bowel and womb cancers every year; 10 per cent of these cancers are thought to be hereditary.

The decade-long study, which involved scientists and clinicians from 43 centres in 16 countries and was funded by Cancer Research UK, followed nearly 1,000 patients, in some cases for over 10 years. The study found that those who had been taking a regular dose of aspirin had 50 per cent fewer incidents of hereditary cancer compared with those who were not taking aspirin.

The research focused on people with Lynch syndrome which is an inherited genetic disorder that causes cancer by affecting genes responsible for detecting and repairing damage in the DNA. Around 50 per cent of those with Lynch syndrome develop cancer, mainly in the bowel and womb. The study looked at all cancers related to the syndrome, and found that almost 30 per cent of the patients not taking aspirin had developed a cancer compared to around 15 per cent of those taking the aspirin.

Those who had taken aspirin still developed the same number of polyps, which are thought to be precursors of cancer, as those who did not take aspirin but they did not go on to develop cancer. It suggests that aspirin could possibly be causing these cells to destruct before they turn cancerous.

Over 1,000 people were diagnosed with bowel cancer in Northern Ireland last year; 400 of these died from the disease. Ten per cent of bowel cancer cases are hereditary and by taking aspirin regularly the number of those dying from the hereditary form of the disease could be halved.

Professor Patrick Morrison from Queen's University in Belfast, who led the Northern Ireland part of the study, said: "The results of this study, which has been ongoing for over a decade, proves that the regular intake of aspirin over a prolonged period halves the risk of developing hereditary cancers. The effects of aspirin in the first five years of the study were not clear but in those who took aspirin for between five and ten years the results were very clear."

"This is a huge breakthrough in terms of cancer prevention. For those who have a history of hereditary cancers in their family, like bowel and womb cancers, this will be welcome news. Not only does it show we can reduce cancer rates and ultimately deaths, it opens up other avenues for further cancer prevention research. We aim now to go forward with another trial to assess the most effective dosage of aspirin for hereditary cancer prevention and to look at the use of aspirin in the general population as a way of reducing the risk of bowel cancer.

"For anyone considering taking aspirin I would recommend discussing this with your GP first as aspirin is known to bring with it a risk of stomach complaints, including ulcers."

The research was published online Oct. 28 in The Lancet.

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Sir John Burn, Anne-Marie Gerdes, Finlay Macrae, Jukka-Pekka Mecklin, Gabriela Moeslein, Sylviane Olschwang, Diane Eccles, Gareth Evans, Eamonn R. Maher, Lucio Bertario, Marie-Luise Bisgaard, Malcolm G. Dunlop, Judy W.C. Ho, Shirley V. Hodgson, Annika Lindblom, Jan Lubinski, Patrick J. Morrison, Victoria Murday, Raj Ramesar, Lucy Side, Rodney J. Scott, Huw J.W. Thomas, Hans F. Vasen, Gail Barker, Gillian Crawford, Faye Elliott, Mohammad Movahedi, Kirsi Pylvanainen, Juul T. Wijnen, Riccardo Fodde, Henry T. Lynch, John C. Mathers, D. Timothy Bishop, on behalf of the CAPP2 Investigators. Long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer: an analysis from the CAPP2 randomised controlled trial. The Lancet, Pubished online Oct. 28, 2011; DOI: 10.1016/S0140-6736(11)61049-0

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ScienceDaily (Oct. 27, 2011) — Official assessments of a doctor's professionalism should be considered carefully before being accepted due to the tendency for some doctors to receive lower scores than others, and the tendency of some groups of patient or colleague assessors to provide lower scores, claims new research published online in the British Medical Journal.

Researchers from the Peninsula College of Medicine and Dentistry in Exeter investigated whether there were any potential patient, colleague and doctor-related sources of bias evident in the assessment of doctors' professionalism.

Doctors' regulator the General Medical Council (GMC) is working on a new system of revalidation for all UK doctors that could be introduced next year as a way of ensuring doctors are fit to continue to practise. This is likely to involve the use of multi-source feedback from patients, peers and supervisors as part of the evidence used to judge a clinician's performance.

The researchers used data from two questionnaires completed by patients and colleagues. A group of 1,065 doctors from 11 different settings, including mostly NHS sites and one independent sector organisation, took part in the study.

They were asked to nominate up to 20 medical and non-medically trained colleagues to take part in an online secure survey about their professionalism, as well as passing on a post-consultation questionnaire to 45 patients each. Collectively, the doctors returned completed questionnaires from 17,031 colleagues and 30,333 patients.

Analysis of the results that allowed for characteristics of the doctor and the patient to be taken into account, showed that doctors were less likely to receive favourable patient feedback if their primary medical degree was from any non-European country.

Several other factors also tended to mean doctors got less positive feedback from patients, such as that they practised as a psychiatrist, the responding patient was not white, and the responding patient reported that they were not seeing their "usual doctor."

From colleagues, there was likely to be less positive feedback if the doctor in question had received their degree from any country other than the UK or South Asia. Other factors that predicted a less favourable review from colleagues included that the doctor was working in a locum capacity, the doctor was working as a GP or psychiatrist, or the colleague did not have daily or weekly professional contact with the doctor.

The researchers say they have identified possible "systematic bias" in the assessment of doctors' professionalism.

They conclude: "Systematic bias may exist in the assessment of doctors' professionalism arising from the characteristics of the assessors giving feedback, and from the personal characteristics of the doctor being assessed. In the absence of a standardised measure of professionalism, doctor's assessment scores from multisource feedback should be interpreted carefully, and, at least initially, be used primarily to help inform doctor's professional development."

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John L. Campbell, Martin Roberts, Christine Wright, Jacqueline Hill, Michael Greco, Matthew Taylor, Suzanne Richards. Factors associated with variability in the assessment of UK doctors’ professionalism: analysis of survey results. BMJ, 2011; 343: d6212 DOI: 10.1136/bmj.d6212

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ScienceDaily (Oct. 28, 2011) — A team of researchers at MIT has found one of the most effective catalysts ever discovered for splitting oxygen atoms from water molecules -- a key reaction for advanced energy-storage systems, including electrolyzers, to produce hydrogen fuel and rechargeable batteries. This new catalyst liberates oxygen at more than 10 times the rate of the best previously known catalyst of its type.

The new compound, composed of cobalt, iron and oxygen with other metals, splits oxygen from water (called the Oxygen Evolution Reaction, or OER) at a rate at least an order of magnitude higher than the compound currently considered the gold standard for such reactions, the team says. The compound's high level of activity was predicted from a systematic experimental study that looked at the catalytic activity of 10 known compounds.

The team, which includes materials science and engineering graduate student Jin Suntivich, mechanical engineering graduate student Kevin J. May and professor Yang Shao-Horn, published their results in Science on Oct. 28.

The scientists found that reactivity depended on a specific characteristic: the configuration of the outermost electron of transition metal ions. They were able to use this information to predict the high reactivity of the new compound -- which they then confirmed in lab tests.

"We not only identified a fundamental principle" that governs the OER activity of different compounds, "but also we actually found this new compound" based on that principle, says Shao-Horn, the Gail E. Kendall (1978) Associate Professor of Mechanical Engineering and Materials Science and Engineering.

Many other groups have been searching for more efficient catalysts to speed the splitting of water into hydrogen and oxygen. This reaction is key to the production of hydrogen as a fuel to be used in cars; the operation of some rechargeable batteries, including zinc-air batteries; and to generate electricity in devices called fuel cells. Two catalysts are needed for such a reaction -- one that liberates the hydrogen atoms, and another for the oxygen atoms -- but the oxygen reaction has been the limiting factor in such systems.

Other groups, including one led by MIT's Daniel Nocera, have focused on similar catalysts that can operate -- in a so-called "artificial leaf" -- at low cost in ordinary water. But such reactions can occur with higher efficiency in alkaline solutions, which are required for the best previously known catalyst, iridium oxide, as well as for this new compound.

Shao-Horn and her collaborators are now working with Nocera, integrating their catalyst with his artificial leaf to produce a self-contained system to generate hydrogen and oxygen when placed in an alkaline solution. They will also be exploring different configurations of the catalyst material to better understand the mechanisms involved. Their initial tests used a powder form of the catalyst; now they plan to try thin films to better understand the reactions.

In addition, even though they have already found the highest rate of activity yet seen, they plan to continue searching for even more efficient catalyst materials. "It's our belief that there may be others with even higher activity," Shao-Horn says.

Jens Norskov, a professor of chemical engineering at Stanford University and director of the Suncat Center for Interface Science and Catalysis there, who was not involved in this work, says, "I find this an extremely interesting 'rational design' approach to finding new catalysts for a very important and demanding problem."

The research, which was done in collaboration with visiting professor Hubert A. Gasteiger (currently a professor at the Technische Universität München in Germany) and professor John B. Goodenough from the University of Texas at Austin, was supported by the U.S. Department of Energy's Hydrogen Initiative, the National Science Foundation, the Toyota Motor Corporation and the Chesonis Foundation.

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The above story is reprinted from materials provided by Massachusetts Institute of Technology. The original article was written by David L. Chandler, MIT News Office.

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J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough, Y. Shao-Horn. A Perovskite Oxide Optimized for Oxygen Evolution Catalysis from Molecular Orbital Principles. Science, 2011; DOI: 10.1126/science.1212858

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ScienceDaily (Oct. 27, 2011) — A team of computer scientists, physicists, and physicians at Harvard has developed a simple yet powerful method of visualizing human arteries that may result in more accurate diagnoses of atherosclerosis and heart disease.

The prototype tool, called "HemoVis," creates a 2D diagram of arteries that performs better than the traditional 3D, rainbow-colored model. In a clinical setting, the tool has been shown to increase diagnostic accuracy from 39% to 91%.

Presented Oct. 27 at the IEEE Information Visualization Conference(InfoVis 2011), the new visualization methodoffers insight to clinicians, imaging specialists, engineers, and others in a wide range of fields who need to explore and evaluate complex, branching structures.

"Our goal was to design a visual representation of the data that was as accurate and efficient for patient diagnosis as possible," says lead author Michelle Borkin, a doctoral candidate at the Harvard School of Engineering and Applied Sciences (SEAS). "What we found is that the prettiest, most popular visualization is not always the most effective."

HemoVis takes data from patient-specific blood flow simulations, combined with traditional imaging data, and visually displays a tree diagram of the arteries with areas of disease highlighted to assist in diagnosis.

Tools for artery visualization in both clinical and research settings commonly use 3D models that portray the shape and spatial arrangement of vessels of interest. These complex tools require users to rotate the models to get a complete perspective of spatial orientation.

By contrast, the new visualization requires no such rotation or interaction. The tool utilizes 2D, circumference-adjusted cylindrical cross sections arranged in tree diagrams.

Though this visualization method may seem less high-tech, the team demonstrated through quantitative evaluation with medical experts that the 2D model is actually more accurate and efficient for patient diagnosis.

"In the 3D case, the more complex and branched the arteries were, the longer it took to complete the patient diagnosis, and the lower the accuracy was," Borkin reflects. "In the 2D representation, it didn't matter how many branches we had or how complex they were -- we got consistently fast, accurate results. We weren't expecting that."

Tree diagrams are hardly new, as evolutionary biologists will attest, but scientists in many fields are using them to solve a range of very modern and complex problems. In fact, Borkin applied her own experience in astronomy and physics to transform the concept of visualization for SEAS' Multiscale Hemodynamics research group. In prior work, she had used a very similar type of tree diagram to determine the structure of nebulae in outer space.

"With the consultation and cooperation of clinicians, we were able to draw on fairly well known visualization techniques and principles from computer science to solve a practical clinical problem," says Hanspeter Pfister, Gordon McKay Professor of the Practice of Computer Science at SEAS.

Borkin, Pfister, and their colleagues relied on the input of physicians and others with clinical or laboratory imaging experience throughout the process. Through extensive surveys and interviews, they identified the most popular options for display, accurate layout, and coloring of these arterial projections.

However, Borkin drew on well supported research that is less well known outside the visualization community:

"For years, visualization, computer science, and psychology researchers have identified that color is critical for conveying the value of data, but that the rainbow coloring is not well-attuned to the human visual system."

Accordingly, HemoVis departs from the traditional practice of rainbow color-coding in favor of a graded single-color scheme (red to black) that can represent placement along a continuum.

In tests, diagnostic accuracy, as measured by the proportion of diseased areas identified, increased dramatically with the new color scheme.

Widespread adoption of visual representations like those in HemoVis could have the effect of not only optimizing tasks that are critical for doctors, but also changing long-entrenched mindsets and making scientists "think twice" about their assumptions in data visualization, Borkin says.

"This approach to visualization design and validation is broadly applicable in medicine, engineering, and science," notes Pfister. "We hope that people will use this process as a template for transforming their own visualizations."

Borkin and Pfister acknowledged that while HemoVis represents an important step forward, traditional 3D artery models still play a role, particularly in providing a spatially intuitive tool for surgical planning.

With this in mind, the next steps for this research include further development and optimization of the 2D tool and investigation into how it might complement, rather than replace, its 3D counterpart.

A paper about this work will be published later this year in the journal IEEE Transactions on Visualization and Computer Graphics.

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