April 8, 2009, 5:06 AM CT
Treating drug-resistant prostate cancer
A new treatment for metastatic prostate cancer has shown considerable promise in early clinical trials involving patients whose disease has become resistant to current drugs.
Of 30 men who received low doses of one the drugs in a multisite phase I/II trial designed to evaluate safety, 22 showed a sustained decline in the level of prostate specific antigen (PSA) in their blood. Phase III clinical trials are planned to evaluate the drug's effect on survival in a large group of patients with metastatic prostate cancer.
The drugs are second-generation antiandrogen therapies that prevent male hormones from stimulating growth of prostate cancer cells. The new compounds manufactured by the pharmaceutical company Medivation and known as MDV3100 and RD162 appear to work well even in prostate cells that have a heightened sensitivity to hormones. That heightened sensitivity makes prostate cancer cells resistant to existing antiandrogen therapies.
The drugs were discovered in the laboratory of Howard Hughes Medical Institute investigator Charles Sawyers at Memorial Sloan-Kettering Cancer Center in collaboration with chemist Michael Jung at UCLA. He and colleagues described the development of the drugs and initial testing in an article posted online April 9, 2009, in Science
Express, which provides electronic publication of selected Science
articles in advance of print. Sawyers's team collaborated on the studies with scientists from the University of California Los Angeles, Oregon Health and Science University, University of Washington and Medivation.........
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April 7, 2009, 5:27 AM CT
How the retina works: Like a multi-layered jigsaw puzzle
Each neuron in the retina views the world through a small, irregularly shaped window. These regions fit together like pieces of a puzzle, preventing "blind spot" and excessive overlap that could blur our perception of the world.
Credit: Image: Courtesy of Dr. Jeffrey Gauthier, Salk Institute for Biological Studies
About 1.25 million neurons in the retina -- each of which views the world only through a small jagged window called a receptive field -- collectively form the seamless picture we rely on to navigate our environment. Receptive fields fit together like pieces of a puzzle, preventing "blind spots" and excessive overlap that could blur our perception of the world, as per scientists at the Salk Institute for Biological Studies.
In the April 7 issue of the journal Public Library of Science, Biology
, the researchers say their findings suggest that the nervous system operates with higher precision than previously appreciated and that apparent irregularities in individual cells may actually be coordinated and finely tuned to make the most of the world around us.
Previously, the observed irregularities of individual receptive fields suggested that the collective visual coverage might be uneven and irregular, potentially posing a problem for high-resolution vision. "The striking coordination we found when we examined a whole population indicated that neuronal circuits in the retina may sample the visual scene with high precision, perhaps in a manner that approaches the optimum for high-resolution vision," says senior author E.J. Chichilnisky, Ph.D., an associate professor in the Systems Neurobiology Laboratories.........
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April 7, 2009, 5:15 AM CT
Wise to trust the female nose
It appears to be wise to trust the female nose when it comes to body odor. As per new research from the Monell Center, it is more difficult to mask underarm odor when women are doing the smelling.
"It is quite difficult to block a woman's awareness of body odor. In contrast, it seems rather easy to do so in men," said study main author Charles J. Wysocki, PhD, a behavioral neuroscientist at Monell.
The scientists speculate that females are more attuned to biologically relevant information in sweat that may guide women when choosing a mate.
In the study, women and men rated the strength of underarm odors, both alone and in conjunction with various fragrances.
The fragrances were selected to test their ability to block underarm odor through a method known as cross-adaptation. Olfactory adaptation refers to the loss of sensitivity to an odor when one is constantly exposed to that odor. Olfactory cross-adaptation occurs when the nose adapts to one odor and then also becomes less sensitive to a second odor.
Sniffed alone, the underarm odors smelled equally strong to men and women. When fragrance was introduced, only two of 32 scents successfully blocked underarm odor when women were doing the smelling; in contrast, 19 fragrances significantly reduced the strength of underarm odor for men.........
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April 7, 2009, 5:12 AM CT
Does acupuncture work in hot flushes?
Acupuncture cannot be shown to have any positive effect on hot flushes during the menopause. This is the conclusion of a systematic review of literature by three groups in Daejon, Busan (South Korea) and Exeter (UK), reported in the current edition of the peer-evaluated journal Climacteric
A number of women are concerned by the unfavourable publicity given to HRT use, but still have to deal with the symptoms which can occur during and after the menopause. A significant minority of women look for alternatives to HRT to deal with these symptoms. Often these alternatives are untested, and it can be impossible to balance the risks and benefits of these therapys against the risks and benefits of conventional therapys or the discomfort of untreated menopause.
The scientists evaluated studies on the use of acupuncture for the relief of hot flushes during the menopause. They identified 106 studies in total, which they eventually narrowed down to the six most relevant to the study. These six studies were randomised controlled trials (RCTs), which included testing the effects of real acupuncture against the effect of sham acupuncture. Only one RCT reported favorable effect of acupuncture on the frequency and severity of hot flush after 4 weeks follow-up, while the other five RCTs demonstrated no such effects.........
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April 7, 2009, 5:08 AM CT
Weight gain early in life leads to physical disabilities
Carrying extra weight earlier in life increases the risk of developing problems with mobility in old age, even if the weight is eventually lost, as per new research out of the Sticht Center on Aging at Wake Forest University School of Medicine.
The study, funded by the National Institute on Aging and the Wake Forest University Claude D. Pepper Older Americans Independence Center, appears in the April 15 issue of the American Journal of Epidemiology
"In both men and women, being overweight or obese put them at greater risk of developing mobility limitations in old age, and the longer they had been overweight or obese, the greater the risk," said lead investigator Denise Houston, Ph.D., R.D., an assistant professor of gerontology at the School of Medicine and an expert on aging and nutrition. "We also observed that, if you were of normal weight in old age but had previously been overweight or obese, you were at greater risk for mobility limitations." .
Houston added that dropping weight during the later part of life can lead to problems with mobility because weight loss during the later part of life is commonly involuntary and the result of an underlying chronic condition.
The study is based on data collected in the Health, Aging and Body Composition study, which enrolled Medicare recipients in Pittsburgh, Pa., and Memphis, Tenn., between April 1997 and June 1998. Participants had to be well-functioning, living in the community, and free of life-threatening illness.........
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April 6, 2009, 10:28 PM CT
Substituting water for sugar-sweetened beverages
Replacing consumption of sugar-sweetened beverages (SSBs) with water could eliminate an average of 235 excess calories per day among children and adolescents, as per a research studyreported in the April 2009 Archives of Pediatrics & Adolescent Medicine
The study's authors conclude that such a replacement would be a simple and effective way to reduce excess intake of calories causing childhood overweight and obesity, as well as address dental cavities and other health problems linked to added sugar. And they predict no detrimental effects on nutrition.
"The evidence is now clear that replacing these 'liquid calories' with calorie-free beverage alternatives both at home and in schools represents a key strategy to eliminate excess calories and prevent childhood obesity," said Y. Claire Wang, MD, ScD, assistant professor of Health Policy and Management at Columbia University Mailman School of Public Health and the study's main author.
Dr. Wang and his colleagues analyzed what children and teens reported they ate and drank on two different days, using nationally representative data from the 2003-2004 National Health and Nutrition Examination Survey. They then estimated the impact of substituting water for SSBs on the total energy intake of youths ages two to 19.........
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April 6, 2009, 9:42 PM CT
Avastin for brain cancer
The use of Avastin alone to treat a subgroup of recurrent Grade 3 brain tumors showed it was safe and effective at delaying tumor progression, as per a retrospective study of 22 patients conducted by a researcher at the Seattle Cancer Care Alliance.
The patients all had a recurrent cancerous glioma known as alkylator-refractory anaplastic oligodendroglioma (AO), for which there is no existing standard treatment. Oligodendrogliomas begin in brain cells called oligodendrocytes, which provide support around nerves by building a sheath of myelin and facilitating electrical nerve impulses. The relatively uncommon tumor affects about 2,000 persons annually in the U.S. Most are under age 50.
Avastin, known generically as bevacizumab, is the first approved treatment designed to inhibit angiogenesis, the process by which new blood vessels develop and carry vital nutrients to a tumor. It is approved so far to treat certain metastatic colon cancers and non-small cell lung cancer.
"Bevacizumab is an important drug for us," said Marc Chamberlain, M.D., author of the study reported in the April 15 edition of the journal Cancer
"Of all of the targeted therapies for gliomas, this has been the most promising. And this is practice changing."
Therapy for treating recurrent high-grade gliomas is palliative. All patients with these high-grade tumors eventually die of their cancer. However, bevacizumab has the potential to be the best palliative therapy, as per Chamberlain, who is director of the Neuro-oncology Program at the SCCA and a professor of neurology and neurological surgery at the University of Washington School of Medicine.........
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April 6, 2009, 9:38 PM CT
Bisphosphonate heart rhythm link
New research at Wake Forest University School of Medicine reviewed the link between a common class of drugs used to prevent bone fractures in osteoporosis patients and the development of irregular heartbeat.
The study's findings are reported in the current issue of Drug Safety
, a publication of the International Society of Pharmacovigilance covering the safe and proper use of medicines.
"Some trials show there could be a potential link between the use of bisphosphonates and the development of serious heart rhythm problems, but in our study the link wasn't conclusive," said Sonal Singh, M.D., M.P.H., an assistant professor of internal medicine and lead investigator for the study. "So we urge that additional investigations be conducted".
Bisphosphonates, found in prescription drugs including BonivaTM, FosomaxTM, ReclastTM and ActonelTM, inhibit the breakdown of bones, which reduces the risk of fractures, particularly those of the spine and hips in older patients. The first such drugs were approved for use in the mid-1990s.
Early studies indicated that the use of bisphosphonates might cause problems with heart rhythm, or atrial fibrillation, which increases the risk for stroke or heart attack. For the study published this month, scientists analyzed the data from prior findings based on observation and clinical trials to determine the link between bisphosphonate treatment and irregular heart beat.........
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April 6, 2009, 9:34 PM CT
You Wear Me Out
Exerting self-control is exhausting. In fact, using self-control in one situation impairs our ability to use self-control in subsequent, even unrelated, situations. What about thinking of other people exerting self-control? Earlier research has shown that imagining actions can cause the same reactions as if we were actually performing them (e.g., simulating eating a disgusting food results in a revolting face, even if no food has been eaten) and psychology experts Joshua M. Ackerman and John A. Bargh from Yale University, along with Noah J. Goldstein and Jenessa R. Shapiro from the University of California, Los Angeles explored what affect thinking about other people's self-control has on our own thoughts and behavior.
Participants were presented with a story about a hungry waiter who was surrounded by delicious food, but was not allowed to sample any, for fear of being fired. Half of the participants simply read the story and the other half were told to imagine themselves in the waiter's shoes. Next, all of the participants were shown images of mid- to high-priced items (e.g., cars and TVs) and were to indicate how much they would pay for them. In a follow-up experiment, some of the participants read the same story and others read a similar story in which the waiter was not hungry and did not have to use self-control. Just as in the first experiment, some of the participants read the story while others imagined themselves as the waiter. All of these volunteers then participated in a word game and a memory task.........
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April 6, 2009, 9:25 PM CT
Finding pancreatic cancer early
A cancer scientist from Johns Hopkins has convinced an international group of colleagues to delay their race to find new cancer biomarkers and instead begin a 7,000-hour slog through a compendium of 50,000 scientific articles already published to assemble, decode and analyze the molecules that might herald the furtive presence of pancreas cancer.
With limited resources available for the exhaustive and expensive testing that needs to be done before any candidate can be considered a bona fide biomarker of clinical value, it's important to take stock of the big picture and strategize, says Akhilesh Pandey, M.D., Ph.D., an associate professor in the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, and founder and director of the Institute of Bioinformatics in Bangalore, India.
Having mined the literature to amass 2,516 potential biomarkers of pancreas cancer, Pandey and his team are publishing their compendium on April 6 in PLoS Medicine
They systematically cataloged the genes and proteins that are overexpressed in pancreas cancer patients, then characterized and compared these biomarker candidates in terms of how worthy each is of further study.
More than 200 genes are shortlisted because they were reported in four or more published studies to be overexpressed meaning that the proteins they make are in higher abundance in people with pancreas cancer than in people without the disease. This qualifies them as "excellent candidates" for the further studies that are needed to validate them as sensitive and specific biomarkers, note the authors.........
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