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Feb 10
Creation Of First Crystal Structure Of An Intermediate Particle In Virus Assembly
The structure, described February 8 in an advance online publication of the journal Nature, provides fresh insights into the elegant dance that viral proteins perform to create the infectious structure that causes all manner of misery and disease, say researchers. While the virus they studied, HK97, only infects bacteria, well-known viruses such as herpes and HIV are also known to assemble an "intermediary" structure before morphing into its final assault-proof, infectious form.

"The principles of this multi-stage protein coat assembly will likely be similar across all complex viruses," says the study's senior author, Scripps Research Professor John E. Johnson. "But this process has never been seen before at this resolution, and now we known that what we thought happens, doesn't."

That's important, Johnson says, because if scientists understand how a virus builds its protective coat, they may be able to medically target vulnerabilities in the first stage of that assembly. "We believe that without its final shell to protect it, an immature virus will be much more defenseless to antiviral agents," he says.

Knowing how viruses build these vessels to protect the naked viral DNA inside is also useful in the field of medical nanotechnology, he adds. "The immature coat has lots of holes in it through which we could load drugs, and then seal it in the mature form to produce a potent delivery system," Johnson says.

Johnson and his research team have long studied HK97, and had "solved" the structure of the virus's mature outer coat. It is made up of 72 protein rings - 12 pentagons and 60 hexagons - locked together like the chain mail suits worn by knights. This coating forms the head of the virus, which is extremely small - thousands of times narrower than a human hair.

The thin viral armor offers protection and stability as well as freedom of movement, Johnson says. "This is a container that works very well."

But the researchers say they spent five "painful" years trying to produce a crystal structure of the intermediate particle they knew was assembled first. They had produced images using electron microscopy, but they weren't detailed enough to understand the molecular processes involved.

The scientists built the viral shells in a test tube. Genes that encode the 420 proteins that make up the coat were expressed in e coli bacteria, the normal host of the virus. These proteins spontaneously assemble and form the immature particles. In the presence of viral DNA and the enzymes that pump it into the particles, they instantly form a mature coat that engulfs the genes.

The study's first author, Ilya Gertsman, a researcher in Johnson's lab, kept trying to capture the crystal structure of the intermediate form of the virus, but it always quickly morphed into its final armored form, even without DNA present. Finally, working with collaborators from the University of Pittsburgh, Gertsman used a form of HK97 that was mutated in such a way that made it slow to mature.

What the researchers saw from the crystal structure "was so beautiful," Gertsman says. The proteins that made up the spherical, soccer ball-like form were flat in shape and pointed outward, like hands placed palm to palm in prayer. But the moment the structure "sensed" the presence of DNA it immediately changed shape. In essence, the fingers on the praying hands folded down together, fingers interspersed and grasping each other. "That's why the final protein coat is so stable. The proteins are all intertwined around each other," Johnson says. Previously it was thought that the proteins went through this motion as a nearly rigid unit. This study showed that the proteins significantly changed in structure during the transition. The researchers don't yet know if this structural change happens all at once, or if it moves like a wave around the sphere.

They hypothesize that domains that hang from each of the proteins that eventually form the viral coat drive the process of changing the structure. The tails interact with each other to distort the shape of the proteins, Johnson says. "As long as the tails are there, the process of change is reversible. When the tails are gone (removed by a viral enzyme), the structure becomes stable," he says. Researchers had thought these tails, which are scaffolding proteins, guided assembly of the particle "but we think they actually change the structure," Johnson says. "That offers us another target by which we may be able to interrupt assembly of the coat."

Feb 10
Increasing Understanding And Use Of Imaging Techniques For Neuroscience Research
It's a classic academic mismatch: Researchers aren't able to make use of seminal improvements in technology - often from colleagues just across the street - either because they don't know about them or because gaining familiarity makes unrealistic demands on their time.

For those very reasons, Johns Hopkins' Brain Science Institute is underwriting the Center for Translational Imaging (CTI). The new enterprise aims to channel expertise from Hopkins' various imaging-dedicated centers into creating a surge, university-wide, in the understanding and use of imaging techniques for neuroscience research.

The translational goals are both immediate and long-term, says magnetic resonance physicist and CTI Co-Director Susumu Mori. Immediately, the idea is to make accessible very high-quality anatomical MRI, MR spectroscopy, functional MRI, PET and newer offshoots such as diffusion tensor imaging. The prime targets of such "upgrades" are researchers with basic and clinical neuroscience studies in fields such as neurology, psychiatry, developmental biology, psychology, genetics, pathology and biomedical engineering.

But the center's ultimate purpose - and basis for Brain Science Institute support - upholds the traditional meaning of translational. Ideally, improved imaging in Hopkins' brain-oriented projects will hasten therapies for brain diseases.

The timing is right. "It's no coincidence that we're starting our center now," Mori says. "There's currently a bottleneck in the imaging field that interferes with the progress of biomedical research." But the problem, he says, isn't in the ability to acquire good data from imaging.

"That was the bottleneck 15 years ago," says Mori. "Now, however, high-quality MRI and PET scanners are available. Their new technology lets users access state-of-the-art capabilities just by pushing buttons. Yet we're victims of our own success; quality images are so easily generated that the volume overwhelms researchers and clinicians."

The new bottleneck, Mori says, lies in not being able to quantify information from a glut of images or interpret it rapidly enough. It's the access to good image analysis that must increase.

The CTI aims to improve things, University-wide, with several approaches. First, they'll set up a "protocol core" staffed by expert advisors who'll review proposed studies and offer guidance in collecting images. They'll also refer researchers to an appropriate Hopkins imaging data acquisition site. Sites include the F.M. Kirby Research Center for Functional Brain Imaging at the Kennedy Krieger Institute, the Molecular Imaging Center in the Broadway Research Building, the Department of Radiology's PET Center, Radiology's MRI Service Center and its Animal NMR Service Center.

Once high-quality images are generated, the core serves as a bridge to analysis in several ways. For one, it offers training - both individual and group - in the most widely used image analysis techniques. This educational arm of CTI will make computers and training available on a daily basis. "We anticipate high demand for this service," says Marilyn Albert, another of CTI's co-directors. "The interest is already there."

In addition, the CTI aims to centralize services for image analysis, particularly for projects with high-quality anatomical images. Though still in the planning stages, two image analysis stations will open, one, under Mori, in the Traylor Building on the medical campus and another, headed by CTI Co-Director Michael Miller, at Homewood's Center for Imaging Science.

At first, CTI will charge for its comprehensive analysis, but the ultimate hope is to automate the process so fully that investigators can perform it, gratis, in their own laboratories. "That ability is critical because it will free the center to create even more advanced image analysis and share it," Mori adds.

Especially helpful, the planners say, is CTI's "grant support core" opening this year. The intent is to provide the pilot funding that lets studies incorporate useful, quality human or animal imaging, making investigators more likely to get outside grant awards.

These improvements will come in phases. While imaging analysis occurs now at Hopkins, CTI's efforts will ultimately add workstations, improve the ease of analysis and foster wider use of high-quality imaging.

The interests of the CTI's three architects bring considerable breadth to the new center. Susumu Mori, with the School of Medicine's Department of Radiology, was key in developing the MRI capability to study brain anatomy.

Biomedical Engineering's Michael Miller, who directs the Center for Imaging Science in the Whiting School of Engineering, pioneered the field of computational anatomy. Getting computers to generate anatomically correct brain regions, he says, should enable scientists to relate changes in brain structure to patient symptoms in schizophrenia, depression, Alzheimer's disease and others.

Neurology's Marilyn Albert, who directs that department's Division of Cognitive Neuroscience, is well known for work to understand the clinical biomarkers - including those derived from brain imaging - associated with aging and Alzheimer's disease.

Feb 10
Multivitamins Don't Change Cancer Or Heart Risk In Postmenopausal Women
A large scale US study of postmenopausal women found no convincing evidence that long term use of multivitamins changes the risk of developing common cancers, cardiovascular disease or premature death.

The study was led by researchers from the Fred Hutchinson Cancer Research Center in Seattle, Washington and is published in the 9 February online issue of the Archives of Internal Medicine.

The authors wrote that millions of postmenopausal women take multivitamins, many of them in the hope that they will prevent chronic diseases like cancer and cardiovascular disease. They decided to investigate whether there was any evidence to support this.

In a separate statement, lead author Dr Marian L Neuhouser, an associate member of the Public Health Sciences Division at the Hutchinson Center, said:

"Dietary supplements are used by more than half of all Americans, who spend more than 20 billion dollars on these products each year. However, scientific data are lacking on the long-term health benefits of supplements."

For the study, Neuhouser and colleagues included 161,808 women taking part in the Women's Health Initiative clinical trials: just over 40 per cent were in overlapping trials of hormone therapy, dietary interventions, and calcium and vitamin D supplements, and just under 60 per cent of them were taking part in an observational study (ie they were going about their normal day to day lives with no particular interventions, and those who took multivitamins did so from personal choice).

The Women's Health Initiative is one of the largest US prevention studies of its kind and is looking at the most common causes of death, disability and impairments to quality of life in postmenopausal women.

The researchers collected detailed data on all participants at the start of the study (baseline) and at intervals throughout the study period. The women enrolled between 1993 and 1998, and were followed for a median of 8 years in the clinical trials and 7.9 years in the observational study.

Incidence of mortality and disease were noted up to 2005, including invasive breast cancers, cancers of the colon/rectum, kidney, bladder, stomach, ovary, and lung. The researchers also noted cases of cardiovascular disease, such as myocardial infarction (heart attack), stroke, and venous thromboembolism (blood clot).

The results revealed:

* 41.5 per cent of all the women in the study used multivitamins.

* Multivitamin users were more likely to be white, reside in the western United States, have a lower BMI (body mass index), be more physically active and have a higher level of educational attainment compared to non-users.

* Compared to non users, multivitamin users were also more likely to drink alcohol and less likely to smoke, and they reported eating more fruits and vegetables and eating less fat than non-users.

* After the follow up period (median of 8.0 years in the clinical trial and 7.9 years in the observational study), there were: 9,619 cases of cancer (breast, colorectal, endometrial, kidney, bladder, stomach, lung and ovarian); 8,751 cardiovascular events; and 9,865 deaths.

* A statistical tool called multivariate adjusted analysis showed no link between multivitamin use and risk of cancer, cardiovascular disease and death (none of the hazard ratios were very far from 1.00, with 95 per cent confidence intervals ranging from 0.85 to 1.29 for venous thromboembolism and 0.91 to 1.05 for breast cancer).

The authors concluded that:

"After a median follow-up of 8.0 and 7.9 years in the clinical trial and observational study cohorts, respectively, the Women's Health Initiative study provided convincing evidence that multivitamin use has little or no influence on the risk of common cancers, CVD [cardiovascular disease], or total mortality in postmenopausal women."

Neuhouser said:

"To our surprise, we found that multivitamins did not lower the risk of the most common cancers and also had no impact on heart disease."

The results are consistent with those of other studies that also found no health benefits from using multivitamins. However this Women's Health Initiative study is more definitive said Neuhouser, because:

"The Women's Health Initiative is one of the largest studies ever done on diet and health. Thus, because we have such a large and diverse sample size, including women from 40 sites across the nation, our results can be generalized to a healthy population."

But because the study did not involve men, you can't say the results apply to them.

Neuhouser suggested that women concentrate on getting their nutrients from food rather than supplements:

"Whole foods are better than dietary supplements. Getting a wide variety of fruits, vegetables and whole grains is particularly important," she said.

Feb 10
One In Three Smokers Would Quit For Sake Of Pets, US Study
Researchers surveying pet owners living in Michigan, USA, found that one in three of the smokers said knowing smoking was bad for their pet's health would make them quit and about one in ten said this would make them ask other smokers they lived with to quit.

The study was carried out by researchers from the Center for Health Promotion and Disease Prevention, Henry Ford Health System in Detroit, Michigan, and is published online on 10 February in the BMJ journal Tobacco Control.

Although studies show that second hand smoke harms humans and animals, there is not a lot of information on the proportion of pet owners who either smoke themselves or allow others to smoke in their homes.

Second hand smoke has been linked with lymph gland, nasal, and lung cancers, plus a range of allergies, diseases of eye and skin, and respiratory problems in cats and dogs.

For this study, the researchers carried out a web-based survery of 3,293 adult pet owners living in the state of Michigan, USA. They asked them about their smoking status, whether any people living with them smoked, whether they allowed smoking in the home or not, and how knowing about the effects of second hand smoke on animal health would change their intentions about smoking and their smoking policies.

The results showed that:

* 21 per cent of the respondents were current smokers.

* 27 per cent of the respondents lived with at least one other person who smoked.

* 28.4 per cent of respondents who smoked said that knowing about the risks of second hand smoke to animal health would make them try to quit.

* 8.7 per cent of respondents said knowing about the risks of second hand smoke to animal health would make them ask co-habitant smokers to quit.

* 14.2 per cent said that knowing about the risks of second hand smoke to animal health would make them change their smoking policy to ban smoking indoors.

* 16.4 per cent of respondents who were non-smokers but lived with smokers said they would ask their co-habitants to quit.

* 24 per cent of non-smokers who lived with smokers said they would be interested in receiving information about smoking, quitting and the effects of second hand smoke.

The authors concluded that:

"Educational campaigns informing pet owners of the risks of SHS [second hand smoke] exposure for pets could motivate some owners to quit smoking. It could also motivate these owners and non-smoking owners who cohabit with smokers make their homes smoke-free."

They said that pet owners are a devoted bunch and would make good targets for anti-smoking public health campaigns that focus on the effects of second hand smoke on animals.

Nearly two thirds of US homes has at least one pet, and Americans spend about 10 billion dollars a year on pet supplies.

But the depth of devotion that Americans have for their pets is perhaps reflected in the results of a recent survey referred to by the authors as carried out by the American Animal Hospital Association where half the respondents are reported to have said if they were stranded on a desert island they would prefer to have their pet with them rather than another person.

Feb 09
Bacteria defenses gut against cancer
The presence of bacteria in the human gut could produce substances that protect against colon cancer and provide therapy for inflammatory bowel disease.
Researchers from the University of Aberdeen Rowett Institute of Nutrition and Health and from the MTT Agrifood Research Institute in Finland report that bacteria in the gut convert linoleic acid, a naturally-occurring fat in the diet, into a form called conjugated linoleic acid (CLA) which is absorbed by the gut wall.

There are different types of CLA and not all of them have beneficial effects. "The 'good' form of CLA is present in dairy foods such as milk and cheese," said John Wallace of the Rowett Research Institute, "but eating lots of dairy foods won't necessarily help our gut health as most of the fats are digested in the small intestine before they get to the large intestine, where most of our gut bacteria are found."

The results of these latest studies showed that several different forms of CLA are produced by gut bacteria. Fortunately, most was of the "good" kind, but Wallace stressed that more extensive studies are needed. One subject produced small amounts of a CLA whose beneficial or otherwise effects are much less clear.

The implications are that, if small quantities of dietary linoleic acid can be delivered to the large intestine, the effects on gut health will be generally beneficial in most people, said an Abereen release.

"The results are of special interest for individuals using anti-obesity treatments that prevent the small intestine from absorbing fats. This means that those fats - including linoleic acid - will pass into the large intestine and the gut bacteria will produce CLA. It has to be the correct CLA, so it is important to understand how individuals produce different CLA. This must depend on which types of bacteria are present," Wallace said

Feb 09
Weight loss cures sleep apnea
Losing weight could be the most effective way of reducing obstructive sleep apnea or OSA symptoms and associated disorders, says a new study.
Weight loss may not be a new miracle pill or a fancy high-tech treatment, but it is an exciting therapy for sufferers of OSA both because of its short- and long-term effectiveness and for its relatively modest price tag.

The prospective, randomised trial found that, in 81 patients with mild OSA, the 40 patients who were in the intervention arm underwent a diet that strictly limited caloric intake combined with lifestyle counseling lost more than 20 pounds on average in a year - and kept it off, resulting in markedly lower symptoms of OSA.

"Very low calorie diet (VLCD) combined with active lifestyle counseling resulting in marked weight reduction is a feasible and effective treatment for the majority of patients with mild OSA, and the achieved beneficial outcomes are maintained at one-year follow-up," wrote Henri P.I. Tuomilehto, department of otorhinolaryngology at the Kuopio University Hospital in Finland.

The 41 patients in the control arm, who only received lifestyle counseling and lost on average less than 6 pounds, and were much less likely to see improvements in their OSA. And not only does sustained weight loss improve OSA, it also improves the many other independently linked co-morbidities such as hypertension, high cholesterol, and diabetes, said a Kupio release.

"The greater the change in body weight or waist circumference, the greater was the improvement in OSA." In fact, mild OSA was objectively cured in 88 percent of the patients who lost more than 33 pounds, a statistic that declined with the amount of weight lost, said Tuomilehto.

Feb 06
Fat cells help weight reduction
Georgia State University researchers have discovered that fat cells in the body work in the same fashion as a thermostat regulates
temperature inside a house—giving feedback to the brain to regulate the process of fat burning.

C. Kay Song and Tim Bartness, who conducted this study in collaboration with Gary J. Schwartz of the Albert Einstein College of Medicine, say that their work may help advance the scientific understanding of how weight is shed. The researchers found that during the process of burning fat, known as lipolysis, fat cells use sensory nerves to feed information to the brain.

The team revealed that they used viruses to trace communications in the nerves of Siberian hamsters, and found that the brain uses part of the nervous system used to regulate body functions, called the sympathetic nervous system, to in turn communicate back to the cells to initiate, continue or stop the fat burning depending upon the information the brain receives from the fat.

"The brain can trigger lipid burning by fat cells and through these sensory nerves, the fat cell can give the brain feedback. This is a really important concept in biology, as it can regulate the process of lipolysis much like how a thermostat regulates temperature in your house, using input from the air and output to a furnace or heating unit," Bartness said.

"The presence and function of the sensory nerves has been completely ignored and the areas in the brain that receive this sensory information were unknown until we did these studies," he added.

When the body has a low amount of a carbohydrate called glycogen, which acts as fuel for lipolysis, the body starts this process to release energy stored in fats. Finally, nerves that are part of the sympathetic nervous system, a chemical called nor epinephrine are released to trigger the breakdown of fat.

Bartness says that sensory nerves later inform the brain about the status of the lipolysis, communicating whether too much or too little energy has been released – and the activity of the sympathetic nerves can be adjusted accordingly.

"If you're doing a moderate amount of exercise or even if it has been a fairly long interval since you last ate, you will use up all or most of the available glycogen, necessitating the break down fat to yield sufficient energy. But you don't want to break down more than you need. So, this would be a way to stop the sympathetic nervous system from triggering the release of too much lipid energy from fat," he said.

According to the researchers, though this communication process is known to play a role in the short-term burning of fat, it has yet to be determined whether this process is involved with the long-term issues of burning fat – important in understanding obesity and why some people burn fat more readily than others.

"It could be that sensory nerves have a dual function. In addition to the moment-to-moment lipolysis process, they might also have a longer term function. It's complicated, and it might be a different subset of the sensory nerves performing the long-term monitoring of fat reserves," he said.

Feb 06
Teen brains still budding
Are you clueless as to why your teenage kid ignores home rules? Well, British scientists have got the answer: their brain's ability to adopt the viewpoint of others is still budding.

Dubbed as the theory of mind, the ability to infer another's perspective - emotional, intellectual, or visual -boosts with age.

To reach the conclusion, the researchers made kids watch two puppets - Sally and Anne - play with a marble, then put the marble back in a box. Anne "left" and Sally grabbed the marble, played with it, and then returned the marble instead to a bag.

Where will Anne first search for the marble, the researchers asked the children as part of the study.

"Before four, kids say she's going to look in the bag, but after four they know she has a false belief," New Scientist quoted Iroise Dumontheil, a cognitive neuroscientist at University College London, UK, who led the new study.

However, Dumontheil said, brain scans suggest that a teenage mind toils harder when inferring the outlook of others, compared with adults. And a brain region implicated in theory of mind, the medial prefrontal cortex, continues to develop through adolescence, the scientist added.

To see if there is a behavioural consequence of these biological changes, she and colleagues tested children, adolescents, and adults on their ability to infer the spatial perspective of another person in a simple computer game.

Volunteers- 179 females ranging in age from 7 to 27 - saw a bookshelf with a variety of different sized balls and other objects on four different rows. Few of the objects sit in front of opaque backgrounds, obscured to someone standing on the other side of the shelf, while some sit in front of a see-through background.

Participants were asked to adopt the perspective of a man standing on the other side of the shelf and move the small ball to the left, using a mouse. In a typical test, a golf ball and tennis ball are both visible to the participant, but the golf ball is obscured from the point of view of the observer.
The correct response, then, is to move the tennis ball.

Kids under the age of 10 moved the wrong ball in about three-quarters of trials. Children aged 10 through 13 scored marginally better, and teens answered wrong on two-thirds of trials. Adults, however, did better than 50-50, on average.

Feb 05
Too much screen time risky for asthmatic kids
WASHINGTON: Too much screen time can have an adverse impact on the health of urban children with asthma, according a new study.
The urban children with asthma engage in an average of an hour more of screen time daily.

"We know that both asthma and excessive screen time can be associated with other difficulties, including behaviour problems, difficulty with attention, poor school performance and obesity," said Kelly M. Conn, M.P.H., of General Pediatrics at Golisano Children's Hospital at Strong and lead author of the study.

During the study, the researchers surveyed parents of urban children with asthma in Rochester, NY, to better understand their screen time viewing habits.

The screen time includes TV watching and video tapes, playing video and computer games and using the Internet.

The study found that 74 percent of the 226 children whose parents were surveyed exceeded more than two hours of screen time per day. On average, these children with asthma watched 3.4 hours daily.

The widespread presence and popularity of screen time activities in children's lives makes monitoring and setting limits for screen use very difficult. In addition, in an urban setting, safety concerns often limit a child's ability to engage in activities outside of the home.

Even though the goals of asthma therapy are to quell asthmatic symptoms and prevent limitations with activities, about 63 percent of children used screen time when their asthma symptoms physically limited their activities.

Those children who used screens when they were having physically limiting symptoms used an average of 3.67 hours daily, which is more than half an hour extra daily than children who engaged in other non-physical activities such as resting, reading or colouring.

Children with asthma most likely watch a similar amount of screen time to all children, but children with asthma are more at risk for the health problems associated with too much screen time.

Conn suggests that parents of children with asthma can encourage a variety of alternate activities for their child, including reading, drawing and arts and crafts, or playing board games or puzzles.

In addition, if a child is experiencing limitation of activity due to their asthma, parents should speak with their child's medical provider about ways to improve their asthma control.

"It is not unreasonable or uncommon for children to watch TV or play a video game when they are not feeling well or when they need to slow down their activity," said Conn.

"For all children, it is important for parents to be aware of how much screen time their children have and the types of programs they are watching," she added.

Feb 05
Working men more prone to eye injuries
SYDNEY: Working men are more likely than women to suffer eye injuries, according to an Australian report released on Thursday
The report by Australian Institute of Health and Welfare (AIHW) said about half the visits to the general practitioner for eye injuries were associated with a foreign body in the eye. Four-fifths of those visits involved men - the majority of whom were of working age.

"While eye injuries constitute just 0.2 percentage of GP (general practitioner) visits, they make up about six percent of emergency department visits," Clare Bradley of AIHW'S National Injury Surveillance Unit was quoted as saying in a statement by the institute.

"A foreign body in the eye was also the most common reason for treatment in the emergency department and eye-related injury compensation claims, with the median time lost from work being about a week and a half," said Bradley.

"Conversely, fractures of the bones around the eye and superficial injury around the eye were the most common first diagnoses for hospitalized eye injuries," she added.

About a quarter (23 percent) of emergency department visits were due to a person being struck by, or colliding with, an object. Another 12 percent were due to being struck by, or colliding with, another person.

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