February 4, 2008, 9:51 PM CT
Grapefruit compound may help combat hepatitis C
A compound that naturally occurs in grapefruit and other citrus fruits may be able to block the secretion of hepatitis C virus (HCV) from infected cells, a process mandatory to maintain chronic infection. A team of scientists from the Massachusetts General Hospital Center for Engineering in Medicine (MGH-CEM) report that HCV is bound to very low-density lipoprotein (vLDL, a so-called bad cholesterol) when it is secreted from liver cells and that the viral secretion mandatory to pass infection to other cells may be blocked by the common flavonoid naringenin.
If the results of this study extend to human patients, a combination of naringenin and antiviral medicine might allow patient to clear the virus from their livers. The report will appear in an upcoming issue of the journal Hepatology and has been released online.
By finding that HCV is secreted from infected cells by latching onto vLDL, we have identified a key pathway in the viral lifecycle, says Yaakov Nahmias, PhD, of the MGH-CEM, the papers lead author. These results suggest that lipid-lowering drugs, as well as supplements, such as naringenin, may be combined with traditional antiviral therapies to reduce or even eliminate HCV from infected patients.
HCV is the leading cause of chronic viral liver disease in the United States and infects about 3 percent of the world population. Current antiviral medications are effective in only half of infected patients, 70 percent of whom develop chronic infection that can lead to cirrhosis or liver cancer. Since the virus does not integrate its genetic material into the DNA of infected cells the way HIV does, totally clearing the virus could be possible if new cells were not being infected by secreted virus.........
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February 4, 2008, 9:21 PM CT
Microneedles enhance drug administration
Microscopic needle transdermal patch.
Credit: Courtesy of Georgia Institute of Technology
In what is thought to bethe first peer-evaluated study of its kind involving human subjects, scientists at the University of Kentucky College of Pharmacy and the Georgia Institute of Technology have demonstrated that patches coated on one side with microscopic needles can facilitate transdermal delivery of clinically-relevant doses of a drug that normally cannot pass through the skin.
Published in the journal Proceedings of the National Academy of Sciences, the study could help advance the use of microneedles as a painless method for delivering drugs, proteins, DNA and vaccines into the body. The research also found other advantages for the microneedles, including an ability to produce therapeutic drug levels with lower doses, and lowered production of metabolites that may cause side-effects.
This proof-of-concept study shows that microneedles work in humans for transdermal drug delivery, said Daniel Wermeling, associate professor in the Department of Pharmacy Practice and Science at UK's College of Pharmacy. Success with microneedles could cause us to rethink the convergence of the drug and delivery system and lead to a more integrated approach merging engineering with pharmaceutical technology.
The research was supported by the National Institutes of Health and the University of Kentucky Research Foundation.........
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January 28, 2008, 5:15 AM CT
Stroke victims may benefit from stem cell transplants
As per two studies reported in the current issue of CELL TRANSPLANTATION (Vol.16 No.10), stroke victims may benefit from human mesenchymal stem cell (hMSC) or bone marrow stromal cell (BMSCs) transplantation. In both studies, the migration of chemically tagged transplanted stem cells were tracked to determine the degree to which the transplanted cells reached damaged areas of the brain and became therapeutically active.
Tracking transplanted hMSCs to infarcted areas
In a study carried out by Korean researchers, labeled hMSCs (early precursor cells to musculoskeletal, blood, vascular and urogenital systems) were transplanted into animal stroke models with cerebral artery occlusion and tracked by magnetic resonance imaging (MRI) at two days, one week, two weeks, six weeks and ten weeks after transplant.
Cells started showing indications of migration as early as one or two weeks following transplantation, said lead author Jihwan, Song, DPhil, of the Pochon CHA University College of Medicine. At 10 weeks, the majority of the cells were detected in the core of the infarcted area.
The study concluded that there is a strong tendency for transplanted hMSCs to migrate toward the infarcted area regardless of injection site but that the degree of migration was likely based on differences in each animals ischemic condition.........
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January 21, 2008, 8:34 PM CT
Studies highlight MRSA evolution and resilience
S. aureus bacteria escaping destruction by human white blood cells
Credit: Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases (NIAID)
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are caused primarily by a single strainUSA300of an evolving bacterium that has spread with extraordinary transmissibility throughout the United States during the past five years, as per a new study led by National Institutes of Health (NIH) scientists. CA-MRSA, an emerging public health concern, typically causes readily treatable soft-tissue infections such as boils, but also can lead to life-threatening conditions that are difficult to treat.
The study, from the National Institute of Allergy and Infectious Diseases (NIAID) of NIH, resolves debate about the molecular evolution of CA-MRSA in the United States. The findings rule out the previously held possibility that multiple strains of USA300, the most troublesome type of CA-MRSA in the United States, emerged randomly with similar characteristics. The study also offers a hypothesis for the origin of prior S. aureus outbreaks, such as those caused by penicillin-resistant strains in the 1950s and 1960s.
A second study led by the same NIAID researchers takes the issue of the evolution of MRSA a step further, revealing new information about how MRSA bacteria in general, including the USA300 group, elude the human immune system.........
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January 17, 2008, 9:30 PM CT
Next Generation Optical Fibres
Electron microscope image of the hollow-core fibre
Researchers have discovered a way of speeding up the production of hollow-core optical fibres - a new generation of optical fibres that could lead to faster and more powerful computing and telecommunications technologies.
The procedure, described today in the journal Optics Express, cuts the production time of hollow-core optical fibres from around a week to a single day, reducing the overall cost of fabrication.
Initial tests show that the fibre is also superior in virtually every respect to prior versions of the technology, making it an important step in the development of new technologies that use light instead of electrical circuits to carry information.
These technologies include faster optical telecommunications, more powerful and accurate laser machining, and the cheaper generation of x-ray or ultra-violet light for use in biomedical and surgical optics.
"This is a major improvement in the development of hollow-core fibre technology," said Professor Jonathan Knight from the Centre for Photonics & Photonic Materials in the Department of Physics at the University of Bath.
"In standard optical fibres, light travels in a small cylindrical core of glass running down the fibre length.
"The fact that light has to travel through glass limits them in a number of ways. For example, the glass can be damaged if there is too much light.........
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January 14, 2008, 5:27 PM CT
A specially developed carrot has been produced to help people absorb more calcium.
Scientists at Texas A&M AgriLifes Vegetable and Fruit Improvement Center studied the calcium intake of humans who ate the carrot and found a net increase in calcium absorption. The research, which was done in collaboration with Baylor College of Medicine, means adding this carrot to the diet can help prevent such diseases as osteoporosis.
If you eat a serving of the modified carrot, youd absorb 41 percent more calcium than from a regular carrot, said Dr. Jay Morris, lead author on the paper, a post doctorate researcher at Baylor College of Medicine in Houston.
The finding will be published in the Proceedings of the National Academy of Sciences online edition Jan. 14.
The primary goal was to increase the calcium in fruit and vegetables to benefit human health and nutrition, Morris said. Fruit and vegetables are good for you for a number of reasons, but they have not been a good source of calcium in the past.
Morris, who worked on the study while earning a doctorate at Texas A&M University, said fruits and vegetables play a role in good bone health for other reasons.
We think that if this technology is applied to a large number of different fruits and vegetables, that would have an even greater impact on preventing osteoporosis, he said.........
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January 14, 2008, 5:17 PM CT
Aggression as rewarding as sex, food and drugs
New research from Vanderbilt University shows for the first time that the brain processes aggression as a reward - much like sex, food and drugs - offering insights into our propensity to fight and our fascination with violent sports like boxing and football.
The research will be published online the week of Jan. 14 by the journal Psychopharmacology.
Aggression occurs among virtually all vertebrates and is necessary to get and keep important resources such as mates, territory and food, Craig Kennedy, professor of special education and pediatrics, said. We have observed that the reward pathway in the brain becomes engaged in response to an aggressive event and that dopamine is involved.
It is well known that dopamine is produced in response to rewarding stimuli such as food, sex and drugs of abuse, Maria Couppis, who conducted the study as her doctoral thesis at Vanderbilt, said. What we have now found is that it also serves as positive reinforcement for aggression.
For the experiments, a pair of mice - one male, one female - was kept in one cage and five intruder mice were kept in a separate cage. The female mouse was temporarily removed, and an intruder mouse was introduced in its place, triggering an aggressive response by the home male mouse. Aggressive behavior included tail rattle, an aggressive sideways stance, boxing and biting.........
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January 14, 2008, 4:57 PM CT
Body weight influenced by thousands of genes
Reporting in the online journal BMC Genetics, scientists from the Monell Center have for the first time attempted to count the number of genes that contribute to obesity and body weight.
The findings suggest that over 6,000 genes about 25 percent of the genome help determine an individuals body weight.
Reports describing the discovery of a new obesity gene have become common in the scientific literature and also the popular press, notes Monell behavioral geneticist Michael G. Tordoff, PhD, an author on the study.
Our results suggest that each newly discovered gene is just one of the a number of thousands that influence body weight, so a quick fix to the obesity problem is unlikely.
To obtain an estimate of how a number of genes contribute to body weight, the Monell scientists surveyed the Jackson Laboratory Mouse Genome Database for information on body weights of knockout mouse strains.
Knockout mice have had a specific gene inactivated, or "knocked out. By studying how the knockout mice differ from normal mice, scientists obtain information about that genes function and how it might contribute to disease. Mice can provide valuable information on human disease because they share a number of genes with humans.
The knockout approach is so useful that the inventors of the technology were awarded the 2007 Nobel Prize in Medicine. Knockout mice are now standard tools in all mouse models of behavior and disease.........
Posted by: JoAnn Read more Source
January 7, 2008, 10:50 PM CT
Trichloroethylene is a risk factor for parkinsonism
Parkinsons disease, the most common neurodegenerative movement disorder caused by aging, can also be caused by pesticides and other neurotoxins. A new study found good evidence that trichloroethylene (TCE) is a risk factor for parkinsonism, a group of nervous disorders with symptoms similar to Parkinsons disease. TCE is a chemical widely used in industry that is also found in drinking water, surface water and soil due to runoff from manufacturing sites where it is used. The study was reported in the October 2007 issue of Annals of Neurology (http://www.interscience.wiley.com/journal/ana), the official journal of the American Neurological Association.
Led by Don M. Gash and John T Slevin, of the University of Kentucky in Lexington, KY, scientists conducting a clinical trial of 10 Parkinsons disease patients came across a patient who described long-term exposure to TCE, which he suspected to be a risk factor in his disease. TCE has been identified as an environmental contaminant in almost 60 percent of the Superfund priority sites listed by the Environmental Protection Agency and there has been increasing concern about its long term effects. The patient noted that some of his co-workers had also developed Parkinsons disease, which led to the current study of this patient and two of his co-workers diagnosed with Parkinsons disease who underwent neurological evaluations to assess motor function. All of these individuals had at least a 25 year history of occupational exposure to TCE, which included both inhalation and exposure to it from submerging their unprotected arms and forearms in a TCE vat or touching parts that had been cleaned in it. In addition, questionnaires about experiencing signs of Parkinsons disease, such as slowness of voluntary movement, stooped posture and trouble with balance, were mailed to 134 former workers. The scientists also conducted studies in rats to determine how TCE affects the brain.........
Posted by: Daniel Read more Source
January 6, 2008, 10:08 PM CT
Key factor in flu infection
Researchers have identified a key factor that determines the ability of influenza viruses to infect cells of the human upper respiratory tracta necessary step for sustaining spread between people. The research, described in the January 6 online edition of Nature Biotechnology and funded by the National Institutes of Health (NIH), offers new insights into how the H5N1 avian flu virus currently circulating in birds would have to change in order to gain a foothold in human populations.
The H5N1 virus has infected several hundred people, but person-to-person transmission has been limited. To trigger a widespread outbreak, experts agree that the bird flu virus must infect the cells lining our noses and throats. We then would spread the virus to others through coughing or sneezing. The latest study, led by Ram Sasisekharan, Ph.D., of the Massachusetts Institute of Technology in Cambridge, refines this notion: The virus can gain access only through a subset of the sugar molecules coating the cells of our upper airways.
"Using an approach that combines experimentation and database analysis, Sasisekharans team has changed our view of flu viruses and how they must adapt to infect us, said Jeremy M. Berg, Ph.D., director of the National Institute of General Medical Sciences, the NIH component that supported the research. The work may improve our ability to monitor the evolution of the H5N1 virus and thwart potential outbreaks.........
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