December 29, 2009, 8:47 AM CT
Exposure to tobacco in childhood
Children regularly exposed to tobacco smoke at home were more likely to develop early emphysema in adulthood. This finding by scientists at Columbia University's Mailman School of Public Health suggests that the lungs may not recover completely from the effects of early-life exposures to tobacco smoke (ETS). The study is reported in the December 2009 American Journal of Epidemiology
This population-based research is the first to examine the association of childhood ETS with early emphysema by Computerized axial tomography scan in nonsmokers. Approximately half of the participants in this large multiethnic cohort had at least one regular cigarette smoker in their childhood home. Participants with more childhood ETS exposure had more emphysema-like lung pixels; an average of 20% of scan pixels were emphysema-like for those who lived with two or more smokers as a child, compared with 18% for those who lived with one regular smoker, or 17% for those who said that they did not live with a regular inside smoker as a child.
The scientists studied Computerized axial tomography scans of 1,781 non-smokers without clinical cardiovascular disease recruited from six communities in the United States, including northern Manhattan and the Bronx, New York. Those reporting childhood ETS exposure were somewhat younger, with an average age of 61; were more likely to be non- Hispanic white; and less likely to have been born outside the United States. These differences were statistically controlled in the analyses.........
Posted by: Scott Read more Source
December 29, 2009, 8:11 AM CT
Schizophrenia mouse model
Scientists at the Medical College of Georgia have created what appears to be a schizophrenic mouse by reducing the inhibition of brain cells involved in complex reasoning and decisions about appropriate social behavior. Pictured is Dr. Lin Mei, a developmental neurobiologist who directs MCG's Institute of Molecular Medicine and Genetics.
Credit: Medical College of Georgia
Researchers have created what may be a schizophrenic mouse by reducing the inhibition of brain cells involved in complex reasoning and decisions about appropriate social behavior.
Findings by Medical College of Georgia scientists, published Dec. 28 in PNAS, elucidate the critical balance between excitation and inhibition of these cells that appears to go awry in schizophrenia. They also provide the first animal model for studying the disabling psychiatric disorder that affects about 1 percent of the population.
"We believe the mouse, which exhibits some of the same aberrant behavior as patients with this disorder, will help identify better therapies," said Dr. Lin Mei, a developmental neurobiologist who directs MCG's Institute of Molecular Medicine and Genetics. "We are doing testing to see if antipsychotic drugs already on the market are effective in treating the mouse".
MCG researchers made the mouse by deleting a candidate gene for schizophrenia, ErbB4, from interneurons, which are brain cells that help shower larger decision-making neurons, called pyramidal cells, with inhibition.
In their earlier work, they identified how ErbB4 and another candidate gene, neuregulin-1, work together to balance the activity of these pyramidal cells. They reported in Neuron in May 2007 that the two help keep a healthy balance between excitation and inhibition by increasing release of GABA, a major inhibitory neurotransmitter in the inhibitory synapses of the brain's prefrontal cortex. Seven years earlier, they showed the two also put a damper on excitatory synapses, communication points between neurons where the neurotransmitter glutamate excites cells to action.........
Posted by: JoAnn Read more Source
December 29, 2009, 8:08 AM CT
A controller of brain circuitry
A pyramidal neuron in the mouse cerebral cortex is labeled using the Golgi technique.
Credit: Image by Tracy Tran, David Ginty and Alex Kolodkin of Johns Hopkins Medicine
By combining a research technique that dates back 136 years with modern molecular genetics, a Johns Hopkins neuroscientist has been able to see how a mammal's brain shrewdly revisits and reuses the same molecular cues to control the complex design of its circuits.
Details of the observation in lab mice, published Dec. 24 in Nature
, reveal that semaphorin, a protein found in the developing nervous system that guides filament-like processes, called axons, from nerve cells to their appropriate targets during embryonic life, apparently assumes an entirely different role later on, once axons reach their targets. In postnatal development and adulthood, semaphorins appear to be regulating the creation of synapses those connections that chemically link nerve cells.
"With this discovery we're able to understand how semaphorins regulate the number of synapses and their distribution in the part of the brain involved in conscious thought," says David Ginty, Ph.D., a professor in the neuroscience department at the Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute investigator. "It's a major step forward, we believe, in our understanding of the assembly of neural circuits that underlie behavior."
Because the brain's activity is determined by how and where these connections form, Ginty says that semaphorin's newly defined role could have an impact on how researchers think about the early origins of autism, schizophrenia, epilepsy and other neurological disorders.........
Posted by: Daniel Read more Source
December 24, 2009, 10:14 PM CT
Vitamin C boosts the reprogramming of adult cells into stem cells
Famous for its antioxidant properties and role in tissue repair, vitamin C is touted as beneficial for illnesses ranging from the common cold to cancer and perhaps even for slowing the aging process. Now, a study published online on December 24th by Cell Press in the journal Cell Stem Cell
uncovers an unexpected new role for this natural compound: facilitating the generation of embryonic-like stem cells from adult cells.
Over the past few years, we have learned that adult cells can be reprogrammed into cells with characteristics similar to embryonic stem cells by turning on a select set of genes. Eventhough the reprogrammed cells, called induced pluripotent stem cells (iPSCs), have tremendous potential for regenerative medicine, the conversion is extremely inefficient.
"The low efficiency of the reprogramming process has hampered progress with this technology and is indicative of how little we understand it. Further, this process is most challenging in human cells, raising a significant barrier for producing iPSCs and serious concerns about the quality of the cells that are generated," explains senior study author Dr. Duanqing Pei from the South China Institute for Stem Cell Biology and Regenerative Medicine at the Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences.........
Posted by: Scott Read more Source
December 24, 2009, 10:13 PM CT
New tool in the fight against mosquito-borne disease
Earlier this year, scientists showed that they could cut the lives of disease-carrying mosquitoes in half by infecting them with a bacterium they took from fruit flies. Now, a new report in the December 24th issue of Cell
, a Cell Press publication, suggests that their strategy might do one better: The Wolbachia bacteria also makes the mosquitoes more resistant to infection by viruses that are a growing threat to humans, including those responsible for dengue fever and Chikungunya.
Once infected with Wolbachia, Aedes aegypti
mosquitoes also become less suitable as hosts for a form of malaria parasite that infects birds, said Scott O'Neill of The University of Queensland. (The mosquitoes under study aren't natural carriers of human malaria.).
"This might be very powerful in reducing pathogen transmission by Aedes aegypti
to humans, especially for dengue and Chikungunya," O'Neill said. "Together with the previously described life-shortening effects, the results suggest we might be able to have a major impact on disease." That's if it can be shown that the Wolbachia infection can invade natural mosquito populations, he added, a question his team is working on right now.
There is no vaccine or cure for dengue fever, which is a painful and debilitating disease suffered by some 50 million people worldwide every year. Dengue haemorrhagic fever, the more severe form of the disease, kills more than 40,000 people annually. Chikungunya commonly isn't fatal, but can cause symptoms similar to dengue. Human epidemics of Chikungunya have been cited in Africa, Asia and more recently in Europe, as per the CDC.........
Posted by: Mark Read more Source
December 24, 2009, 10:10 PM CT
Self-seeding of cancer cells
Cancer progression is usually thought of as a process involving the growth of a primary tumor followed by metastasis, in which cancer cells leave the primary tumor and spread to distant organs. A newly released study by scientists at Memorial Sloan-Kettering Cancer Center shows that circulating tumor cells cancer cells that break away from a primary tumor and disseminate to other areas of the body can also return to and grow in their tumor of origin, a newly discovered process called "self-seeding."
The findings of the study, reported in the December 25 issue of the journal Cell
, suggest that self-seeding can enhance tumor growth through the release of signals that promote angiogenesis, invasion, and metastasis.
"Our work not only provides evidence for the self-seeding phenomenon and reveals the mechanism of this process, but it also shows the possible role of self-seeding in tumor progression," said the study's first author Mi-Young Kim, PhD, Research Fellow in the Cancer Biology and Genetics Program at Memorial Sloan-Kettering.
As per the research, which was conducted in mice, self-seeding involves two distinct functions: the ability of a tumor to attract its own circulating progeny and the ability of circulating tumor cells to re-infiltrate the tumor in response to this attraction. The researchers identified four genes that are responsible for executing these functions: IL-6 and IL-8, which attract the most aggressive segment of the circulating tumor cells population, and FSCN1 and MMP1, which mediate the infiltration of circulating tumor cells into a tumor.........
Posted by: Janet Read more Source
December 24, 2009, 7:09 AM CT
Future-minded people make better decisions
When New Year's Eve rolls around and you're deciding whether to have another glass of champagne, your decision appears to be predicted by your perspective of the future.
A pair of Kansas State University scientists observed that people who tend to think in the long term are more likely to make positive decisions about their health, whether it's how much they drink, what they eat, or their decision to wear sunscreen.
"If you are more willing to pick later, larger rewards rather than taking the immediate payoff, you are more future-minded than present-minded," said James Daugherty, a doctoral student in psychology who led the study. "You're more likely to exercise and less likely to smoke and drink".
Daugherty conducted the research with Gary Brase, K-State associate professor of psychology. The research was presented in November at the Society for Judgment and Decision Making conference in Boston. It also appears in the January 2010 issue of the journal Personality and Individual Differences
In addition to comparing people's perspectives on time with their health behaviors, the scientists also wanted to see what type of time perspective measurements are better at predicting health behaviors.
To answer both of these questions, Daugherty and Brase had subjects college students, with an average age of 19 years old answer surveys about whether they think in the short term or the long term.........
Posted by: Janet Read more Source
December 23, 2009, 11:03 PM CT
Sleeping Off Childhood?
Are your 11- and 12-year-olds staying up later, then dozing off at school the next day? Parents and educators who notice poor sleeping patterns in their children should take note of new research from Tel Aviv University ? and prepare themselves for bigger changes to come.
Prof. Avi Sadeh of TAU's Department of Psychology suggests that changes in children's sleep patterns are evident just before the onset of physical changes linked to puberty. He counsels parents and educators to make sure that pre-pubescent children get the good, healthy sleep that their growing and changing bodies need.
"It is very important for parents to be aware of the importance of sleep for their developing children and to maintain their supervision throughout the adolescent years," says Sadeh, who reported his research findings in a recent issue of the journal Sleep. "School health education should also provide children with compelling information on how insufficient sleep compromises their well-being, psychological functioning and school achievements".Every minute counts
Results of the study, supported by the Israel Science Foundation, show that over a two-year period, sleep onset was significantly delayed by an average of 50 minutes in the study subjects, and sleep time was significantly reduced by an average of 37 minutes. Girls also had higher sleep efficiency and reported fewer night wakings than boys. For both, initial levels of sleep predicted an increase in pubertal development over time. This suggests that the neurobehavioral changes linked to puberty appears to be seen earlier in sleep organization than in bodily changes.........
Posted by: JoAnn Read more Source
December 23, 2009, 11:01 PM CT
Anti-inflammatory drugs interfere with aspirin
A newly released study conducted at Ben-Gurion University of the Negev (BGU) reveals that Celebrex and other anti-inflammatory coxib medications may counter the positive effects of aspirin in preventing blood clots.
The research, reported in the Proceedings of the National Academy of Sciences
), indicates that people who are taking aspirin and coxibs together are in fact inhibiting the aspirin's effectiveness in preventing heart attacks and strokes.
"This finding strongly suggests that humans who are consuming coxibs and a low dose of aspirin simultaneously are exposed to a greater risk of cardiovascular events," said Professor Gilad Rimon, Department of Clinical Pharmacology, Ben-Gurion University of the Negev in Israel.
In the past decade, a new group of anti-inflammatory drugs, coxibs, which include Celebrex and Arcoxia was developed to treat arthritis as well as other pain. Arthritis patients who take Celebrex are instructed to take low-dose aspirin to counteract Celebrex's own potential clot-promoting effect.
Aspirin is the oldest and one of the most effective non steroidal anti-inflammatory drugs. It is also well known for its ability to prevent the blood clots that can potentially lead to heart attack and stroke. Therefore, doctors often advise patients who are more prone to heart-related illnesses to take a daily tablet of low dose aspirin (81 mg). Approximately, 50 million Americans take aspirin every day to reduce their risk of cardiovascular diseases.........
Posted by: Daniel Read more Source
December 23, 2009, 8:05 AM CT
Improving mammogram accuracy
Members of a Syracuse University research team have shown that an obscure phenomenon called stochastic resonance (SR) can improve the clarity of signals in systems such as radar, sonar and even radiography, used in medical clinics to detect signs of breast cancer. It does this by adding carefully selected noise to the system.
The result has been a distinct improvement in the system's ability to correctly identify premalignant lesions, plus a 36 percent reduction in false positives. The inventors have developed a novel method of calculating precisely the correct type and level of noise to add to existing noise in radiography or a similar system.
"We see a broad spectrum of applications for this technology," says research assistant professor Hao Chen. "If a system's performance is unsatisfactory, we add noise to the system based on a specific algorithm that can significantly improve system performance".
A patent covering the technology has been issued to Chen, Distinguished Professor Pramod K. Varshney and research professor James Michels. All are linked to SU's L.C. Smith College of Engineering and Computer Science.
In mammography studies carried out by doctoral candidate Renbin Peng, the challenge was to identify clusters of micro-calcifications in breast tissue. These early signs of premalignant conditions average only 0.3 mm in size and offer only subtle contrast with surrounding tissue. In addition to improving detection of these lesions, the group has reduced false positives by more than a third.........
Posted by: Janet Read more Source