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October 19, 2007, 5:05 AM CT

The specific cell that causes eye cancer

The specific cell that causes eye cancer
Retinoblastoma
Investigators at St. Jude Children's Research Hospital have identified the cell that gives rise to the eye cancer retinoblastoma, disproving a long-standing principle of nerve growth and development. The finding suggests for the first time that it may one day be possible for researchers to induce fully developed neurons to multiply and coax the injured brain to repair itself.

A report of this work appears in the Oct. 19 issue of the journal Cell. Michael Dyer, Ph.D., an associate member in the St. Jude Department of Developmental Neurobiology, is the reports senior author.

Retinoblastoma arises in the retinathe multi-layered, membrane lining the back of the eye that responds to light by generating nerve impulses that are carried into the brain by the optic nerve.

The immediate importance of the St. Jude finding is that it unexpectedly showed that retinoblastoma can arise from fully matured nerves in the retina called horizontal interneurons. This disproves the scientific principle that fully formed, mature nerves cannot multiply like young, immature cells, Dyer said. Human neurodegenerative disorders such as Alzheimers disease can occur when differentiated nerves in the brain try to multiply, and in the process, trigger a self-destruct program called apoptosis. Differentiation is the process by which cells lose their primitive, stem-cell-like properties that include the ability to grow and multiply, and instead develop specialized shapes and functions.........

Posted by: Mike      Read more         Source


October 15, 2007, 4:40 PM CT

Simple eye scan opens window to multiple sclerosis

Simple eye scan opens window to multiple sclerosis
A five-minute eye exam might prove to be an inexpensive and effective way to gauge and track the debilitating neurological disease multiple sclerosis, potentially complementing costly magnetic resonance imaging to detect brain shrinkage - a characteristic of the diseases progression.

A Johns Hopkins-based study of a group of 40 multiple sclerosis (MS) patients used a process called optical coherence tomography (OCT) to scan the layers of nerve fibers of the retina in the back of the eye, which become the optic nerve. The process, which uses a desktop machine similar to a slit-lamp, is simple and painless. The retinal nerve fiber layer is the one part of the brain where nerve cells are not covered with the fat and protein sheathing called myelin, making this assessment specific for nerve damage as opposed to brain MRI changes, which reflect an array of different types of tissue processes in the brain.

Results of the scans were calibrated using accepted norms for retinal fiber thickness and then in comparison to an MRI of each of the patients brains - also calibrated using accepted norms. Experimenters found a correlation coefficient of 0.46, after accounting for age differences. Correlation coefficients represent how closely two variables are related -- in this case MRI of the brain and OComputerized axial tomography scans. Correlation coefficients range from -1 (a perfect opposing correlation) through 0 (no correlation) to +1 (a perfect positive correlation). In a subset of patients with relapsing remitting MS, the most common form of the disease, the correlation coefficient jumped to 0.69, suggesting an even stronger association between the retinal measurement and brain atrophy.........

Posted by: Daniel      Read more         Source


October 8, 2007, 8:32 AM CT

Limiting refined carbohydrates may stall AMD progression

Limiting refined carbohydrates may stall AMD progression
Eating fewer refined carbohydrates may slow the progression of age-related macular degeneration (AMD), as per a new study from scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

AMD results in partial or total blindness in 7 to 15% of the elderly, as per the Eye Diseases Prevalence Research Group. Dietary changes may be the most practical and cost-effective prevention method to combat progression of AMD, says Allen Taylor, PhD, director of the Laboratory for Nutrition and Vision Research at the USDA HNRCA. It is surprising there is so little attention focused on the relationship between AMD and carbohydrates.

The current study, reported in the recent issue of the American Journal of Clinical Nutrition, builds on a recent analysis by Taylor and his colleagues that found men and women older than 55 who consumed diets with higher-than-average dietary glycemic index foods appeared to have an increased risk for both early and later stages of AMD.

Dietary glycemic index is a scale used to determine how quickly carbohydrates are broken down into blood sugar, or glucose. Foods with a high glycemic index are linked to a faster rise and subsequent drop in blood sugar. Refined carbohydrates like white bread and white rice have high glycemic indices. Whole wheat versions of rice, pasta and bread are examples of foods with low glycemic indices.........

Posted by: Mike      Read more         Source


September 25, 2007, 5:04 AM CT

Eye Movement Can Affect Problem-solving

Eye Movement Can Affect Problem-solving
A pair of Beckman Institute scientists has discovered that by directing the eye movements of test subjects they were able to affect the participants' ability to solve a problem, demonstrating that eye movement is not just a function of cognition but can actually affect our cognitive processes.

Prior research (Grant and Spivey, 2003) has shown a relationship between eye movements and problem-solving but Psychology Professor Alejandro Lleras, a member of the Human Perception and Performance group, and Ph.D. candidate Laura Thomas have taken that work in a groundbreaking direction.

They report in the current (Aug., 2007) issue of Psychonomic Bulletin and Review that by occasionally guiding the eye movements of participants with a tracking task uncorrelation to the problem, they were able to "substantially affect their chances of problem-solving success" to the point where those groups outperformed every control group at solving the problem. These results, they conclude, demonstrate that "it is now clear that not only do eye movements reflect what we are thinking, they can also influence how we think".

The prior work of Grant and Spivey suggested a relationship between eye movements and problem-solving by showing that certain patterns of eye movement were reflected as participants got closer to solving the problem.........

Posted by: Mike      Read more         Source


September 11, 2007, 11:36 PM CT

Glaucoma surgery in the blink of an eye

Glaucoma surgery in the blink of an eye
TAU Prof. Ehud Assia and Dr. Ami Eyel (IOPtima) use the laser in a pre-clinical trial.

Credit: AFTAU
Prof. Ehud Assia, of Tel Aviv Universitys Sackler School of Medicine is, quite simply, a rock star in the field of eye surgery.

One of a small number of surgeons in the world who currently perform a complicated form of glaucoma surgery, Prof. Assia has developed a novel laser device that promises to revolutionize therapy of the disease. The laser, called the OTS134 for now, is expected to give most practicing eye surgeons the ability to master complex glaucoma surgery very quickly.

Glaucoma, nicknamed the silent sight thief, is the second leading cause of blindness in the West. Glaucoma is a serious problem that starts to cause nerve damage to people without them realizing that anything is happening to their eyesight, often before it is too late, says Prof. Assia, who is also the director of Ophthalmology at Meir Hospital in Israel, which treats thousands of glaucoma patients each year.

The most common surgical therapy in use today perforates the wall of the eye, often resulting in collapse of the eyeball, infection, cataract formation and other complications. A more effective and elegant approach, a specialty of Prof. Assia's, involves penetration of the eye wall to a depth of only about 95 percent, leaving a razor-thin layer intact. The difference between success and failure may amount to just a few microns.........

Posted by: Mike      Read more         Source


September 4, 2007, 7:16 PM CT

Promising Drug Combination For Ocular Melanoma

Promising Drug Combination For Ocular Melanoma
Image courtesy of looc.org.uk
A combination of two drugs shows promise in treating a rare and treatment-resistant type of melanoma that originates in the eye and spreads to other organs, as per a new study led by Duke University Comprehensive Cancer Center researchers.

The drugs -- decitabine, which can turn on certain genes in cancer cells, and interferon gamma, an immune system protein -- may work together to cause cancer cell death.

"Metastatic uveal melanoma, or melanoma that originates in the eye and spreads to other parts of the body, has been very difficult to treat, in fact there have been no effective therapies to date," said Jared Gollob, M.D., a medical oncologist at Duke and lead investigator on the study. "This study could lead to a very promising new treatment for patients who previously had very little hope."

The scientists published their findings in the September 1, 2007 issue of the journal Clinical Cancer Research. The study was funded by the National Institutes of Health.

This pre-clinical study came on the heels of prior lab work examining proteins called interferons, which originate from immune system cells. These proteins were shown to boost immune function and directly affect melanoma cells, inhibiting their growth and accelerating their death, Gollob said.........

Posted by: Mike      Read more         Source


August 27, 2007, 8:28 PM CT

Link Between Zinc And Macular Degeneration

Link Between Zinc And Macular Degeneration
A team of scientists, including three scientists at George Mason University, observed that the mineral zinc could play a role in the development of macular degeneration. In studying eye tissue samples, the researches observed that deposits, that are hallmarks of age-related macular degeneration (AMD), contain large amounts of zinc.

This finding, reported in the journal Experimental Eye Research, might be especially important because zinc supplements are widely given to patients to help boost weak immune systems. In addition, a 2001 study from the National Eye Institute observed that high doses of zinc supplements, combined with antioxidants, may postpone the progression to blindness.

AMD is a medical condition in which the macula, the place of central vision in the eye, experiences atrophy and in some cases bleeding. It is the primary cause of blindness in the elderly in Western society and approximately 13 million Americans suffer from the disease as per AMD Alliance International.

"Because earlier findings have shown that that zinc contributes to deposit formation in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease, we were prompted to test the theory that zinc might be involved in deposit formation in AMD," said Mason professor of psychology, Jane Flinn.........

Posted by: Mike      Read more         Source


August 7, 2007, 10:52 PM CT

Miniature implanted devices could treat epilepsy, glaucoma

Miniature implanted devices could treat epilepsy, glaucoma
Pedro Irazoqui
developed new miniature devices designed to be implanted in the brain to predict and prevent epileptic seizures and a nanotech sensor for implantation in the eye to treat glaucoma.

Findings will be detailed in three research papers being presented at the Engineering in Medicine and Biology Society's Sciences and Technologies for Health conference from Aug. 23-26 in Lyon, France.

One research project focuses on a tiny transmitter three times the width of a human hair to be implanted below the scalp to detect the signs of an epileptic seizure before it occurs. The system will record neural signals relayed by electrodes in various points in the brain, said Pedro Irazoqui (pronounced Ear-a-THOkee), an assistant professor of biomedical engineering.

"When epileptics have a seizure, a particular part of the brain starts firing in a way that is abnormal," Irazoqui said. "Being able to record signals from several parts of the brain at the same time enables you to predict when a seizure is about to start, and then you can take steps to prevent it".

Data from the implanted transmitter will be picked up by an external receiver, also being developed by the Purdue researchers.

The most critical aspect of the research is creating a device that transmits a large amount of data at low power. The transmitter consumes 8.8 milliwatts, or about one-third as much power as other implantable transmitters while transmitting 10 times more data. Another key advantage is that the transmitter has the capacity to collect data specifically correlation to epileptic seizures from 1,000 channels, or locations in the brain, Irazoqui said.........

Posted by: Mike      Read more         Source


August 1, 2007, 9:12 PM CT

New Treatment For Glaucoma

New Treatment For Glaucoma
(left to right:) Veterinary ophthalmologist Dr. Sinisa Grozdanic, doctoral student Matt Harper and neuroscientist Donald Sakaguchi have developed a new technique that successfully treated rats for blindness caused by glaucoma. (Photo by Bob Elbert)
Iowa State University scientists have developed a new technique that successfully treated rats for blindness caused by glaucoma. Their experimental therapy will be used on canine patients in the next year. If proved to be successful, it is expected to move to human trials.

An estimated 3 million people in the U. S. are affected by glaucoma, the second leading cause of blindness in the developed world and the number one cause of vision loss among blacks. People with elevated intraocular pressure are at greatest risk for developing glaucoma.

Iowa State scientists leading the six-year project are Dr. Sinisa Grozdanic, a veterinary ophthalmologist and assistant professor of veterinary clinical sciences; Donald Sakaguchi, neuroscientist and associate professor of genetics, development and cell biology; and Matt Harper, doctoral student in neuroscience. The team also included scientists from the University of Iowa, Yale University, Tulane University and the University of Miami. The work was presented at a recent meeting of the Association for Research in Vision and Ophthalmology Conference.

The scientists previously determined that animals with glaucoma increase production of proteins with neuron-protective capabilities (neurotrophins) in an attempt to shield against blindness. So, they imitated that process in the laboratory, modifying bone marrow-derived stem cells. Then they transplanted the cells into the eyes.........

Posted by: Mike      Read more         Source


July 5, 2007, 9:24 PM CT

Holograms make for better vision tests

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.........

Posted by: Mike      Read more         Source



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