August 25, 2008, 10:27 PM CT
New hope for stroke patients
If a stroke patient doesn't get therapy within approximately the first three hours of symptoms, there's not much doctors can do to limit damage to the brain.
But now scientists report a technique that potentially could restore functions to patients weeks or even months after a stroke. The technique involves jumpstarting the growth of nerve fibers to compensate for brain cells destroyed by the stroke.
"In the best-case scenario, this would open up the window of time that people could recover and go back to normal functional status," said Gwendolyn Kartje, MD, Ph.D., a professor in the department of cell biology, neurobiology and anatomy and department of neurology at Loyola University Chicago Stritch School of Medicine in Maywood, Ill. and chief of neuroscience research at Edward Hines Jr. VA Hospital in Hines, Ill.
Kartje and his colleagues described the experimental approach, called anti-nogo-A immunotherapy, in a recent review article in the journal Topics in Stroke Rehabilitation
Anti-nogo has dramatically improved functions in lab animals that have experienced strokes. And an ongoing clinical trial in Europe and Canada is testing anti-nogo in humans who have suffered spinal cord injuries.
Most strokes are caused by clots that block blood flow to one part of the brain, killing brain cells within hours. The drug TPA can minimize damage by dissolving the clot. But TPA is safe and effective only when given within about three hours of the onset of symptoms. Most patients don't receive therapy within that brief window. Patients typically arrive at the hospital too late, or hospitals do not begin administering TPA soon enough.........
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August 25, 2008, 10:20 PM CT
Normalizing tumor vessels to improve cancer therapy
Chemotherapy drugs often never reach the tumors they're intended to treat, and radiation treatment is not always effective, because the blood vessels feeding the tumors are abnormal"leaky and twisty" in the words of the late Judah Folkman, MD, founder of the Vascular Biology program at Children's Hospital Boston. Now, Vascular Biology scientists have discovered an explanation for these abnormalities that could, down the road, improve chemotherapy drug delivery. Their findings were reported in the August 12 issue of the Proceedings of the National Academy of Sciences
A tumor's capillariessmall blood vessels that directly deliver oxygen and nutrients to cancer cellsare irregularly shaped, being excessively thin in some areas and forming thick, snarly clumps in others. These malformations create a turbulent, uneven blood flow, so that too much blood goes to one region of the tumor, and too little to another. In addition, the capillary endothelial cells lining the inner surface of tumor capillaries, normally a smooth, tightly-packed sheet, have gaps between them, causing vessel leakiness.
"These abnormal features of tumor vessels impair delivery of circulating chemotherapeutic drugs to the actual tumor site" says Kaustabh Ghosh, PhD, first author on the paper, and a postdoctoral fellow in the laboratory of Donald Ingber, MD, PhD, the paper's senior author and interim co-director of the Vascular Biology program.........
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August 21, 2008, 9:31 PM CT
Malaria researchers identify new mosquito virus
Scientists at the Johns Hopkins Bloomberg School of Public Health's Malaria Research Institute have identified a previously unknown virus that is infectious to Anopheles gambiae
the mosquito primarily responsible for transmitting malaria. As per the researchers, the discovered virus could one day be used to pass on new genetic information to An. gambiae mosquitoes as part of a strategy to control malaria, which kills over one million people worldwide each year. The study was published August 22 online in the peer-evaluated open access journal PLoS Pathogens
The virus, AgDNV, is a densonucleosis virus or "densovirus," which are common to mosquitoes and other insects, but do not infect vertebrate animals such as humans. Eventhough the virus does not appear to harm the mosquitoes, the scientists determined it is highly infectious to mosquito larvae and is easily passed on to the adults.
As per Jason Rasgon, PhD, senior author of the study, the discovery came about serendipitously while the research team was conducting experiments to determine whether Wolbachia bacteria could be used to infect An. gambiae mosquito cells. During the analysis, Xiaoxia Ren, a postdoctoral fellow with Johns Hopkins Malaria Research Institute, noticed an "artifact," that appeared as a prominent band in the gel used to detect the bacteria.........
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August 21, 2008, 9:19 PM CT
Why a common treatment for prostate cancer ultimately fails
Some of the drugs given to a number of men during their fight against prostate cancer can actually spur some cancer cells to grow, scientists have found. The findings were published online this week in a pair of papers in the Proceedings of the National Academy of Sciences
The results may help explain a phenomenon that has bedeviled patients for decades. Hormone treatment, a common therapy for men with advanced prostate cancer, generally keeps the cancer at bay for a year or two. But then, for reasons researchers have never understood, the therapy fails in patients whose disease has spread the cancer begins to grow again, at a time when patients have few therapy options left.
The new findings by a team led by Chawnshang Chang, Ph.D., director of the George Whipple Laboratory for Cancer Research at the University of Rochester Medical Center, help explain the process by showing that the androgen receptor, through which male hormones like testosterone work, is much more versatile than previously thought. Under certain conditions the molecule spurs growth, and at other times the molecule squelches growth just like the same molecule does to hair in different locations on a man's head.
The new findings raise the possibility that under some conditions, some therapys designed to treat prostate cancer could instead remove one of the body's natural brakes on the spread of the disease in the body. The scientists stress that the results are based on laboratory studies and on findings in mice, and it's too soon to know yet whether the findings apply directly to prostate cancer in men.........
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August 21, 2008, 8:44 PM CT
New vaccine to fight multiple influenza strains
A universal vaccine effective against several strains of influenza has passed its first phase of testing, as per Dr. Christine Turley of the University of Texas at Galveston.
Turley, who is director of clinical trials and clinical research at the Sealy Center for Vaccine Development at UTMB and the study's principal investigator, said that VaxInnate's M2e universal vaccine could possibly protect against seasonal and pandemic influenza strains.
"We'd characterize this influenza vaccine candidate as very promising, based upon the immune responses and tolerability we saw in the clinical trial participants," Turley said. "UTMB is committed to further studies of the vaccine candidate, which has the potential to be a safe, highly effective and much-needed option to prevent seasonal and pandemic influenza A."
The results of the study will be presented at the Oct.25-28 joint meeting of the Interscience Conference on Agents and Chemotherapy and the Infectious Disease Society of America (ICAAC/IDSA).
The study was supported by a $9.5 million grant awarded to UTMB by the Bill & Melinda Gates Foundation.
The trial involved 60 young adults in a double-blind, dose-escalating, first time in human, Phase I study to assess the safety and immunogenicity, or the ability to produce a response in the immune system, of the vaccine.........
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August 21, 2008, 8:30 PM CT
How addiction develops
Permanent drug seeking and relapse after renewed drug administration are typical behavioral patterns of addiction. Molecular changes at the connection points in the brain's reward center are directly responsible for this. This finding was published by a research team from the Institute of Mental Health (ZI) in Mannheim, the German Cancer Research Center (DKFZ) in Heidelberg and the University of Geneva, Switzerland, in the latest issue of Neuron
The results provide scientists with new approaches in the medical therapy of drug addiction.
Addiction leaves detectable traces in the brain: In particular regions of the central nervous system, which produce the messenger substance dopamine, the drug cocaine causes molecular restructuring processes at the synapses, the points of correlation between two neurons. As a reaction to the drug, protein subunits are exchanged in specific receptor complexes. As a result, the modified synapse becomes able to transmit nervous signals with enhanced strength a phenomenon that has been termed 'drug-induced synaptic plasticity'. Scientists have suspected for a number of years that drug-induced synaptic plasticity plays a crucial role in addiction development. However, this hypothesis has still not been proven experimentally.
Using genetic engineering, scientists headed by Professor Dr. Gnther Schtz at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) have now been able to selectively switch off those protein components in dopamine-producing neurons that are integrated into the receptor complexes under the influence of cocaine. Jointly with the team of Professor Dr. Rainer Spanagel at the Central Institute of Mental Health (Zentralinstitut fr Seelische Gesundheit, ZI) in Mannheim and the research group of Professor Dr. Christian Lscher at Geneva University, the Heidelberg scientists studied the changes in physiology and behavior of the genetically modified animals.........
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August 20, 2008, 8:21 PM CT
Childhood ear infections may predispose to obesity later in life
Scientists are reporting new evidence of a possible link between a history of moderate to severe middle ear infections in childhood and a tendency to be overweight during the later part of life. Their study suggests that prompt diagnosis and therapy of middle ear infections one of the most common childhood conditions requiring medical attention may help fight obesity in some people. The findings were presented today at the 236th National Meeting of the American Chemical Society (ACS).
Study leader Linda M. Bartoshuk, Ph.D., noted that chronic, repeated ear infections can damage the chorda tympani nerve, which passes through the middle ear and controls taste sensations. Damage to this nerve appears to intensify the desire for fatty or high-energy foods, which could result in obesity, she said.
Other research has shown that middle ear infections, or otitis media, are becoming more common in children. Childhood obesity is likewise on the rise and has reached epidemic levels, especially in the United States. Eventhough researchers have known for years that ear infections can lead to hearing loss in children that can result in speech and language impairment, a possible link between ear infections and obesity has been largely unexplored until now, said Bartoshuk, who is with the University of Florida's Center for Smell and Taste in Gainesville.........
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August 20, 2008, 8:16 PM CT
New test to diagnose osteoarthritis early
This illustration shows a joint with severe osteoarthritis. Osteoarthritis wears away the cartilage at the ends of the bones. Spurs then grow out from the edge of the bone and synovial fluid increases. This may cause the joint to feel stiff and sore.
Credit: Credit: National Institute of Arthritis and Musculoskeletal and Skin Diseases.
A newly developed medical imaging technology may provide doctors with a long-awaited test for early diagnosis of osteoarthritis (OA), researchers from New York reported today at the 236th National Meeting of the American Chemical Society. By far the most common form of arthritis, OA is a bane of the Baby Boom generation, causing joint pain and disability for more than half of those over 65 nearly 21 million people in the United States.
Current diagnostic methods commonly do not catch the disease until OA is in advanced stages when joint damage may already have occurred. A method for early diagnosis could open a window of opportunity for preventing or reducing permanent damage particularly with evidence that dietary supplements like glucosamine and chondroitin can halt further joint degeneration, says Alexej Jerschow, Ph.D., who reported on the research jointly with Ravinder R. Regatte, Ph.D.
"Our methods have the potential of providing early warning signs for cartilage disorders like osteoarthritis, thus potentially avoiding surgery and physical treatment later on," states Jerschow. "Also, the effectiveness of early preventative drug therapies can be better assessed with these methods".
Particularly common in the knee and hip, osteoarthritis damages cartilage, the tough, elastic material that cushions moving parts of joints. OA is the most common reason for total hip and total knee replacement surgery. "It has all these painful consequences and makes it difficult to move it results in a severe loss of quality of life for those who are affected by it," says Regatte.........
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August 20, 2008, 8:07 PM CT
Cervical cancer prevention should focus on vaccination
The cost-effectiveness of vaccination in the United States against human papillomavirus (HPV), a sexually-transmitted virus that causes cervical cancer, will be optimized by achieving universal vaccine coverage in young adolescent girls, by targeting initial "catch-up" efforts to vaccinate women younger than 21 years of age, and by revising current screening policies, as per an analysis by Harvard School of Public Health (HSPH) scientists in the August 21, 2008 issue of The New England Journal (NEJM).
In the U.S. in 2007, cervical cancer developed in more than 11,000 women and killed 3,600 women. Cervical cancer is caused by infection with high-risk "oncogenic" types of HPV, also linked to other cancers. Worldwide, HPV types 16 (HPV-16) and 18 (HPV-18) cause approximately 70% of cervical cancer cases. Vaccines against HPV-16 and HPV-18 appear to be highly efficacious in preventing HPV-16 and HPV-18 infections and cervical disease in females who have not previously been infected with these types. The quadrivalent vaccine currently licensed in the U.S. also prevents low-risk HPV types 6 and 11 (HPV-6 and HPV-11) infections, which are responsible for most genital warts and juvenile-onset recurrent respiratory papillomatosis (JORRP), a rare but severe respiratory condition commonly diagnosed in infancy that may be correlation to a mother's infection with genital warts.........
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August 20, 2008, 6:29 PM CT
How rheumatoid arthritis causes bone loss
Scientists have discovered key details of how rheumatoid arthritis (RA) destroys bone, as per a research studyreported in the Aug. 22 edition of the Journal of Biological Chemistry
The findings are already guiding attempts to design new drugs to reverse RA-related bone loss and may also address more common forms of osteoporosis with a few adjustments.
Two million Americans suffer from rheumatoid arthritis (RA), which causes swelling, pain and deformity in joints and also lead to the thinning of bone. In autoimmune diseases like RA, the body's disease-fighting immune cells mistakenly identify parts of a person's body as foreign invaders, akin to bacteria, and produce chemicals to destroy them. Among the immune chemicals known to play a central in autoimmune disease is tumor necrosis factor alpha (TNF alpha), which ramps up the production of immune cells and chemicals as part of the body's response to disease. When overproduced in RA patients, TNF alpha signals for the destruction of cartilage and bone.
Beyond its control over immune cells, TNF alpha also influences bone mass. Human bone is continually regenerated to maintain strength. Under the control of signaling molecules which include TNF alpha, two cell types, balanced against each other, make bone recycling possible. Osteoclasts break down aging bone to make way for new bone, while osteoblasts build new bone at the sites where osteoclasts have removed it. Going into the study, the field understood that TNF alpha decreases the number of bone-building osteoblasts, but not how. The current study provides the first direct proof that the TNF alpha affects osteoblasts through an enzyme called Smad Ubiquitin Regulatory Factor 1 (Smurf1), which in turn shuts down two proteins that would otherwise drive bone-building.........
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