July 5, 2007, 9:24 PM CT
Holograms make for better vision tests
A sample hologram (not from the study)
A new paper reported in the July 1 issue of OSA's Optics Letters shows that scientists in Australia have created a new one-step test that uses holograms to diagnose the astigmatic error of the human eye, a key measurement in determining the appropriate prescriptions for eye glasses in patients. This new technique adds to an earlier one, developed by the same researchers, for using a single hologram to measure another important property, the spherical refractive error of the eye.Summary
In this new test, patients view a hologram consisting of sunburst patterns; by reporting which sunburst lines appear clearest, the eye doctor can obtain information he or she can use in determining the correct prescription for the patient. Traditionally, patients look through a series of lenses until they find which one gives each eye the clearest view of a distant target such as an eye chart on a wall. This multi-step process of finding the right lens can be cumbersome and complex. Holography offers a number of advantages including simplicity, high speed and low cost and could open new doors in our understanding of human vision. This approach still needs to be tested on young astigmatic individuals, whose nature of vision is not fully known. The same method has also been found to work well in measuring the refractive error of non-astigmatic subjects. The results of that research will appear in a future issue of OSAs journal JOSA-A.........
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July 5, 2007, 9:18 PM CT
New heart disease risk score
A new score for predicting the risk of heart disease gives a more accurate measure of how a number of UK adults are at risk of developing the disease and which adults are most likely to benefit from therapy.
The study published on bmj.com today, estimates that in the general population without pre-existing cardiovascular disease or diabetes, there are 3.2 million adults under the age of 75 in Britain at high risk of developing heart disease. This is lower than prior scores have suggested, but the scientists think that it is a more appropriate estimate for the UK and will help minimise health inequalities.
The study comes as the governments drugs watchdog, the National Institute for Health and Clinical Excellence, recommends that people with a 20% chance of developing heart disease over the next 10 years should be offered statins.
A persons chance of developing heart disease is estimated using standard risk factors such as age, sex, smoking, blood pressure and cholesterol. This risk score is typically based on equations derived from the US Framingham cohort study.
But the Framingham equations tend to over-predict heart disease risk in the UK population and fail to include measures of deprivation, family history of heart disease, body mass index, and therapy with blood pressure lowering drugs, despite known links between these factors and poor health.........
Posted by: Daniel Read more Source
July 5, 2007, 9:06 PM CT
Engineered Blood Vessels Function
Blood vessels that have been tissue-engineered from bone marrow adult stem cells may in the future serve as a patient's own source of new blood vessels following a coronary bypass or other procedures that require vessel replacement, as per new research from the University at Buffalo Department of Chemical and Biological Engineering.
"Our results show that bone marrow is an excellent source of adult stem cells containing smooth muscle and endothelial cells, and that these stem cells can be used in regenerative medicine for cardiovascular applications," said Stelios T. Andreadis, Ph.D., associate professor in the UB Department of Chemical and Biological Engineering in the School of Engineering and Applied Sciences.
Andreadis co-authored the paper, published recently in Cardiovascular Research, with Jin Yu Liu, Ph.D., lead author and a post doctoral researcher in Andreadis' lab.
The research demonstrates the potential for eventually growing tissue-engineered vessels out of stem cells harvested from the patients who need them, providing a desirable alternative to the venous grafts now routinely done in patients undergoing coronary bypass operations.
Disadvantages with venous grafts include limited availability of vessels, pain and discomfort at the donor site and a high 10-year failure rate.........
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July 5, 2007, 8:52 PM CT
Paying attention to attention
Every kid knows that moms have eyes in the back of their heads. We are adept at fixing our gaze on one object while independently directing attention to others. Salk Institute neurobiologists are beginning to tease apart the complex brain networks that enable humans and other higher mammals to achieve this feat.
As per a research findings reported in the July 5, 2007 issue of Neuron, the scientists report two classes of brain cells with distinct roles in visual attention, and highlight at least two mechanisms by which these cells mediate attention. This study represents a major advance in our understanding of visual cognition, because it is the first study of attention to distinguish between different classes of neurons, says system neurobiologist John Reynolds, Ph.D., associate professor in the Systems Neurobiology Laboratory at the Salk Institute.
In the experiments, animals learned how to play a sophisticated video game, which challenged their visual attention-focusing skills. During the game, the Salk scientists recorded electrical activity from individual neurons in part of the visual cortex that has been implicated in mediating visual attention. (Please see video.).
As illustrated in the demonstration, the neurons respond when a stimulus appears within a window (indicated by the circle) covering a small part of the visual field that the eye sees. This window is known as the neurons receptive field. Whenever the stimuli entered the neurons receptive field, the cell produced a volley of electrical spikes, known as action potentials, indicated by vertical tick marks in the demonstration.........
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July 3, 2007, 9:49 PM CT
protecting cancer patients against infertility
Lyon, France: A promising new treatment for protecting the fertility of women with cancer and auto-immune diseases such as lupus was revealed at the 23rd annual conference of the European Society of Human Reproduction and Embryology today (Tuesday 3 July 2007). Dr. Kate Stern, Research Director of the Royal Womens Hospital, Melbourne, Australia, told the conference that her pilot study had shown gonadotropin-releasing hormone (GnRH) antagonists were likely to be able to protect the ovary in women receiving potentially toxic doses of chemotherapy. We are now hoping to carry out a randomised controlled trial to assess the long term protective effect of this therapy, she said .
GnRH analogues are usually used in the management of womens disorders that are dependent on oestrogen production, and in IVF therapies. Dr. Stern and her team studied women between the ages of 18 and 35 years who were due to receive high doses of cyclophosphamide, a chemotherapy drug. They knew that GnHR analogues were already used for the temporary suppression of ovulation in infertility therapy, so reasoned that it would be possible to use it to shut down the ovaries temporarily during the time that chemotherapy was administered, and hence protect them from the effect of the drugs.
The women were given the GnRH antagonist cetrorelix by 3 subcutaneous injections, each of them four days apart, concurrently with their chemotherapy. The researchers found that there was evidence that ovarian function was suppressed, but that this returned to normal after chemotherapy stopped. Follicle stimulating hormone levels were up in 73% of the patients, but these also subsequently returned to normal. 94% of the patients resumed spontaneous ovulation and menses within 12 months.........
Posted by: Janet Read more Source
July 3, 2007, 9:42 PM CT
The elderberry way to perfect skin
Forget expensive moisturisers and cosmetic surgery, a compound found in the humble elderberry could give a natural boost to skin.
In the first study of its kind, a team of scientists led by Prof Aedin Cassidy at the University of East Anglia and Dr Paul Kroon at the Institute of Food Research, will explore whether the skins condition is improved by a compound which gives berries their vibrant colour (called anthocyanin).
In a 12-week trial starting in September, post-menopausal women will consume either extracts from elderberries or placebo capsules, and will have their skins structure and appearance measured with state-of-the-art equipment used by experts in skin science. At the same time, scientists will also test whether the elderberry extract can reduce risk factors for heart disease.
We already know that a healthy diet can help protect against heart disease and skin damage, and that a mixture of similar food components have been shown to improve the skins structure. There is also evidence that the active components have anti-inflammatory properties, which may be important in helping people stay healthy, said UEAs Dr Peter Curtis who is leading the project.
If the results of our study are positive, it may lead to innovations in skin health products and may also give us vital information about diets which promote healthier hearts.........
Posted by: George Read more Source
July 3, 2007, 9:36 PM CT
fireworks that spark seizures
Bright light that flickers frequently or rapidly, like a strobe light, can trigger seizures in some people a phenomenon documented in nearly 700 children who were hospitalized in Japan 10 years ago after watching a Pokemon cartoon. The condition is much on the mind of a neurologist specializing in seizure disorders as the 4th of July holiday with all its fireworks approaches.
While Giuseppe Erba, M.D., is not aware of any instance where fireworks have actually caused a person to have a seizure, the doctor at the University of Rochester Medical Center says that a few people who are extremely sensitive to flashing light might be at risk during holiday celebrations this week, and he recommends a few precautions.
Like a number of seizure specialists, Erba treats patients with photosensitivity an extreme sensitivity to bright, rapidly flickering light that is experienced by some patients with epilepsy and a few otherwise healthy people. In 2004 he led an international committee on behalf of the Epilepsy Foundation that established standards for the video gaming industry to help prevent seizures among gamers, and recently he explained how an animation of a diver used last month to publicize the upcoming 2012 Olympic games in London can cause seizures.
In most people, the brain is able to handle the flood of visual information presented by rapidly flashing lights and repeating patterns. But in some people, the extra stimulation floods the brain and sends cells called neurons into a frenzy in which they fire uncontrollably, causing seizures. The phenomenon can occur when people watch TV, play video games, dance at a concert or club, or even ride in a car, when they are exposed to rapidly flickering light coming through the trees as the car moves along.........
Posted by: Daniel Read more Source
July 3, 2007, 5:01 AM CT
Fat kills cancer
Scientists in Slovakia have been able to derive mesenchymal stem cells from human adipose, or fat, tissue and engineer them into suicide genes that seek out and destroy tumors like tiny homing missiles. This gene treatment approach is a novel way to attack small tumor metastases that evade current detection techniques and therapys, the scientists conclude in the July 1 issue of Cancer Research, a journal of the American Association for Cancer Research.
These fat-derived stem cells could be exploited for personalized cell-based therapeutics, said the studys lead investigator, Cestmir Altaner, Ph.D., D.Sc., an associate professor in the Cancer Research Institute of the Slovak Academy of Sciences in Bratislava. Nearly everyone has some fat tissue they can spare, and this tissue could be a source of cells for cancer therapy that can be adapted into specific vehicles for drug transport.
Mesenchymal stem cells help repair damaged tissue and organs by renewing injured cells. They are also found in the mass of normal cells that mix with cancer cells to make up a solid tumor. Scientists believe mesenchymal stem cells see a tumor as a damaged organ and migrate to it, and so might be utilized as a vehicle for therapy that can find both primary tumors and small metastases. These stem cells also have some plasticity, which means they can be converted by the micro environment of a given tissue into specialized cells, Altaner says.........
Posted by: Janet Read more Source
July 2, 2007, 10:02 PM CT
More Swimmers Means More Pathogens in the Water
The levels of potentially harmful waterborne microorganisms in rivers, lakes and other recreational waterways may be highest when the water is most crowded with swimmers. Scientists at the Johns Hopkins Bloomberg School of Public Health completed two studies at the Hammerman beach area along Maryland's Gunpowder River that linked the number of swimmers using the water with the levels of microsporidian spores and the parasites Cryptosporidium parvum and Giardia lamblia. The studies were made available online in advance of publication in the scientific journals Applied and Environmental Microbiology and Water Research.
Exposure to microorganisms like C. parvum and G. lamblia can cause nausea, vomiting and diarrhea. They can be especially harmful to people with compromised immunity.
"Our research suggests it would be best to test the water when the beach is active to determine if it is safe for recreational use," said Thaddeus K. Graczyk, PhD, co-author of both studies and associate professor with the Bloomberg School's Department of Environmental Health Sciences and Center for Water and Health. As per Graczyk, health officials typically conduct water sampling when there is little human activity.
For both studies, scientists sampled the water at the Hammerman area for 11 weeks during the summer of 2006. Samples were taken on Wednesdays, when beach activity was typically low, and on Saturdays, when activity was commonly high. The scientists also counted the number of swimmers in the water at the time the water was sampled.........
Posted by: Mark Read more Source
July 2, 2007, 9:49 PM CT
Most middle-school boys play violent video games
A new study by scientists at the Massachusetts General Hospitals (MGH) Center for Mental Health and Media dispels some myths and uncovers some surprises about young teens and violent video and computer games. The study, reported in the recent issue of Journal of Adolescent Health, is the first to ask middle-school youth in detail about the video and computer games they play and to analyze how a number of of those titles are rated M (Mature meant for ages 17 and up). It is also the first to ask children why they play video games. Some of the more striking findings include:
- Almost all young teens play video games. Just six percent of the sample had not played any electronic games in the prior six months.
- Most 7th and 8th graders (ages 12 to 14) regularly play violent video games. Two-thirds of boys and more than one in four girls reported playing at least one M-rated game a lot in the past six months.
- A third of boys and one in ten girls play video or computer games almost every day.
- A number of children are playing video games to manage their feelings, including anger and stress. Children who play violent games are more likely to play to get their anger out. They are also more likely to play games with strangers on the Internet.
Contrary to the stereotype of the solitary gamer with no social skills, we observed that children who play M-rated games are actually more likely to play in groups in the same room, or over the Internet, says Cheryl K. Olson, ScD, co-director of the Center for Mental Health and Media and lead author of the study. Boys friendships in particular often center around video games.........
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