October 22, 2006, 11:18 PM CT

Genes And Perception Of Pain

A new NIH-funded study shows that a specific gene variant in humans affects both sensitivity to short-term (acute) pain in healthy volunteers and the risk of developing chronic pain after one kind of back surgery. Blocking increased activity of this gene after nerve injury or inflammation in animals prevented development of chronic pain.

The gene in this study, GCH1, codes for an enzyme called GTP cyclohydrolase. The study suggests that inhibiting GTP cyclohydrolase activity might help to prevent or treat chronic pain, which affects as many as 50 million people in the United States. Doctors also may be able to screen people for the gene variant to predict their risk of chronic post-surgical pain before they undergo surgery. The results appear in the October 22, 2006, advance online publication of Nature Medicine.*.

"This is a completely new pathway that contributes to the development of pain," says Clifford J. Woolf, M.D., of Massachusetts General Hospital and Harvard Medical School in Boston, who led the research. "The study shows that we inherit the extent to which we feel pain, both under normal conditions and after damage to the nervous system."

Dr. Woolf carried out the study in collaboration with Mitchell B. Max, M.D., of the National Institute of Dental and Craniofacial Research (NIDCR) in Bethesda, Maryland, and colleagues at the National Institute on Alcoholism Abuse and Alcoholism (NIAAA) and elsewhere. Dr. Woolf's work was funded by the National Institute of Neurological Disorders and Stroke (NINDS). The research team also received funding from NIDCR, NIAAA, and other organizations.........

Posted by: Sean      Permalink         Source

October 22, 2006, 8:47 PM CT

Portable 'lab on a chip'

Testing soldiers to see if they have been exposed to biological or chemical weapons could soon be much faster and easier, thanks to MIT researchers who are helping to develop a tiny diagnostic device that could be carried into battle.

By tweaking the design of a tiny pump, researchers affiliated with MIT's Institute for Soldier Nanotechnologies have taken a major step towards making an existing miniature "lab on a chip" fully portable, so the tiny device can perform hundreds of chemical experiments in any setting.

"In the same way that miniaturization led to a revolution in computing, the idea is that miniature laboratories of fluid being pumped from one channel to another, with reactions going on here and there, can revolutionize biology and chemistry," says Martin Bazant, associate professor of applied mathematics and leader of the research team.

Within the lab on a chip, biological fluids such as blood are pumped through channels about 10 microns, or millionths of a meter, wide. (A red blood cell is about 8 microns in diameter.) Each channel has its own pumps, which direct the fluids to certain areas of the chip so they can be tested for the presence of specific molecules.

Until now, scientists have been limited to two approaches to designing labs on a chip, neither of which offer portability. The first is to mechanically force fluid through microchannels, but this requires bulky external plumbing and scales poorly with miniaturization.........

Posted by: Sean      Permalink         Source

October 19, 2006, 9:26 PM CT

Protein That Helps Chickenpox Spread

A team of scientists at the National Institute of Allergy and Infectious Diseases (NIAID), one of the National Institutes of Health (NIH), has identified a human protein that helps varicella-zoster virus, the cause of chickenpox and shingles, spread from cell to cell within the body.

NIAID virologist Jeffrey I. Cohen, M.D., and NIAID research fellow Qingxue Li, M.D., Ph.D., discovered that a surface protein of varicella-zoster virus attaches to a cellular protein called insulin-degrading enzyme, using it as a receptor to enter and infect cells. In the October 20, 2006 issue of the journal Cell, they also describe how interfering with this interaction inhibits the spread of virus among cells in the test tube. The discovery of this receptor is important in understanding varicella-zoster virus, say Drs. Cohen and Li.

Their finding is also an important first step towards designing new therapies for shingles. "If safe and effective ways of disrupting this interaction can be found, eventually new interventions may be developed for treating people with this painful and debilitating disease," says NIAID Director Anthony S. Fauci, M.D.

Shingles occurs only in people who have already had chickenpox. Once chickenpox has run its course, some virus remains dormant in nerve cells at the base of the brain and alongside the spinal cord. With advancing age and diminished immunity, the virus can reactivate years later and travel down the nerve cells to the skin. There it multiplies, causing the blistering rash of shingles and damaging sensory nerve endings. The rash usually heals within a few weeks, but the nerve damage sometimes causes one of the worst complications of shingles--a severe type of pain called postherpetic neuralgia, which can last for months or even years.........

Posted by: Sean      Permalink         Source

October 19, 2006, 9:14 PM CT

Connection Between Sound And A Reward

If you've ever wondered how you recognize your mother's voice without seeing her face or how you discern your cell phone's ring in a crowded room, scientists may have another piece of the answer.

Their work indicates that once you figure out your mother's voice is a good thing - most days - fairly significant changes occur in the sensory cortex, the part of the brain that responds to sound.

"When something starts to predict a good outcome is going to happen, the sensory part of the brain that responds to those events starts to respond more strongly, making it easier for the brain to cause a behavioral response," says Dr. David T. Blake, neuroscientist at the Medical College of Georgia and lead author on a study in the Oct. 19 issue of Neuron.

By monitoring the action potentials of about a dozen key neurons in monkey test subjects, scientists found neuronal responsiveness increases dramatically after just a few training sessions.

These neuronal fireworks were short-lived, replaced by a rewiring of the brain that shows the animal has learned, Dr. Blake says.

In the few monkeys that initially didn't make the connection that a change in pitch in a series of sounds meant they were getting a juice reward, no brain changes occurred.........

Posted by: Sean      Permalink         Source

October 19, 2006, 8:54 PM CT

Labor Induction Increases Risk Of Amniotic-fluid Embollism

A Canadian population-based cohort study has revealed that medical induction of labour increases the risk of amniotic-fluid embolism. The study was led by Dr. Michael Kramer, Canadian Institutes of Health Research (CIHR) Senior Investigator from McGill University, and would be published in the October 21st issue of The Lancet.

Amniotic-fluid embolism (AFE) is a rare, but serious and even fatal maternal complication of delivery. While its cause is unknown, it is one of the leading causes of maternal mortality in developed countries, accounting for seven of 44 direct maternal deaths in Canada in the period 1997-2000.

This population-based study examined the association of AFE and medical induction of labour in a cohort of three million hospital births in Canada, for the twelve fiscal years 1991-2002.

"AFE remains a rare occurrence," said Dr. Michael Kramer, principal investigator of the study and Scientific Director of CIHR's Institute of Human Development, Child and Youth Health. "Of the 180 cases of AFE we found, 24 or 13% were fatal. AFE arose almost twice as frequently in women who had medical induction of labour as in those who did not; fatal cases arose 3 times more frequently".

"Dr. Kramer's research has resulted in a discovery that will benefit physicians who look after pregnant women as they will now be aware of this potential complication should they induce labour", said Dr. Joseph Shuster, Interim Scientific Director of the MUHC. "This is an example of how academic university teaching hospitals improve the quality of patient care".........

Posted by: Sean      Permalink         Source

October 18, 2006, 10:43 PM CT

Hospital food not good enough

Montclair, NJ - October 18, 2006 -- Substantial nutrient loss in food occurs in hospital foodservice operations, as per research recently reported in the Journal of Foodservice. The study quantifies how much Vitamin C, as a marker of nutrient quality, is retained at various stages of processing at two New Jersey hospitals.

The nutrient quality of Vitamin C was significantly reduced as a food sample progressed to patients by as much as 86% at a hospital in an inner-city neighborhood. Since a number of nutrients, including Vitamin C, degrade at high temperatures, this loss may be result from food being heated to a temperature much higher than recommended by hospital foodservice so as to still be warm when served to patients.

As improved nutritional status correlates with faster healing and recovery, leading to reduced hospital stays, hospitals need improved cooking methods to reduce the loss of nutrients in foods served to patients. Physicians, dietitians, and menu planners rely on published standard nutritional values, but these standards are derived from experiments made in ideal conditions and fail to consider the various handling, holding, and delivery methods that are common in hospitals. A more vigorous approach to patient nutrition is needed, both in terms of food preparation methods and in assessing the actual nutritional status of patients.........

Posted by: Sean      Permalink         Source

October 17, 2006, 9:35 PM CT

DNA computing targets West Nile Virus

Researchers say that they have developed a DNA-based computer that could lead to faster, more accurate tests for diagnosing West Nile Virus and bird flu. Representing the first "medium-scale integrated molecular circuit," it is the most powerful computing device of its type to date, they say.

The new technology could be used in the future, perhaps in 5 to 10 years, to develop instruments that can simultaneously diagnose and treat cancer, diabetes or other diseases, according to a team of scientists at Columbia University Medical Center in New York and the University of New Mexico, Albuquerque. Their study is scheduled to appear in the recent issue of the American Chemical Society's Nano Letters, a monthly peer-reviewed journal.

"This is a big step in DNA computing," says Joanne Macdonald, Ph.D., a virologist at Columbia University's Department of Medicine. Macdonald led the research team that developed MAYA-II (Molecular Array of YES and AND logic gates) ¯ a "computer" whose circuits consist of DNA instead of silicon. She likens the significance of the advance to the development of the earliest silicon chips. "The study shows that large-scale DNA computers are possible".

"These DNA computers won't compete with silicon computing in terms of speed, but their advantage is that they can be used in fluids, such as a sample of blood or in the body, and make decisions at the level of a single cell," says the researcher, whose work is funded by the National Science Foundation. Her main collaborators in this study were Milan Stojanovic, of Columbia University, and Darko Stefanovic, of the University of New Mexico.........

Posted by: Kevin      Permalink         Source

October 17, 2006, 9:27 PM CT

Childhood Cancer Survivors May Have Low Birth Weight Children

Female childhood cancer survivors may face pregnancy problems, including early deliveries and low birth weight children, according to a study in the October 19 Journal of the National Cancer Institute.

New therapies for childhood cancer patients have increased survival, but many scientists are concerned about the long-term effects of the treatments, particularly for patients exposed to radiation and chemotherapy.

Lisa B. Signorello, Sc.D., of the International Epidemiology Institute in Rockville, Md., and colleagues assessed the records of 1,264 female participants in the Childhood Cancer Survivor Study and their 2,201 children. They compared them with 601 cancer-free siblings of survivors and their 1,175 children. The authors assessed possible long-term effects from treatment, such as preterm births, low birth weight, and having babies who were small for their gestational age.

The authors found that survivors' children were more likely than those of siblings to be born early or underweight. The risk was highest when a survivor had their uterus exposed to pelvic radiation as a child.

"Radiotherapy to the pelvis may raise the risks of both preterm birth and restricted fetal growth," they write.

In an accompanying editorial, Leslie Schover, Ph.D., of the University of Texas M.D. Anderson Cancer Center in Houston, discusses the study and the overall interest in preserving fertility for childhood cancer survivors. "Given the complex terrain our young survivors need to traverse, we should design patient and professional education materials that map out the paths to making informed decisions".........

Posted by: Sean      Permalink         Source

October 16, 2006, 10:21 PM CT

Chemistry To Predict The Dynamics Of Clotting

University of Chicago chemists have demonstrated for the first time how to use a simple laboratory model consisting of only a few chemical reactions to predict when and where blood clotting will occur. The scientists used microfluidics, a technique that allowed them to probe blood clotting on surfaces that mimic vascular damage on the micron scale, a unit of measurement much narrower than the diameter of a human hair.

Although scientists understand what occurs during many of the 80 individual chemical reactions involved in blood clotting, many questions about the dynamics of the entire reaction network remain. Rustem Ismagilov, Associate Professor in Chemistry at the University of Chicago, and graduate students Christian Kastrup, Matthew Runyon and Feng Shen have now developed a technique that will enable scientists to understand the rules governing complex biological reaction networks. They will detail their technique in the online early edition of the Oct. 16-20 issue of the Proceedings of the National Academy of Sciences.

Life and death literally depend on a finely tuned blood-clotting system. "Clotting has to occur at the right place at the right time," Ismagilov said. "A strong, rapid clotting response is essential to stop bleeding at a wound, but such a clotting response at the wrong spot can block blood vessels and can be life-threatening".........

Posted by: Sarah      Permalink         Source

October 16, 2006, 9:56 PM CT

Asthma Linked To Soot From Diesel Trucks

Soot particles spewing from the exhaust of diesel trucks constitute a major contributor to the alarmingly high rates of asthma symptoms among school-aged children in the South Bronx, according to the results of a five-year study by researchers at New York University's School of Medicine and Robert F. Wagner Graduate School of Public Service.

Over the course of the study, asthma symptoms, particularly wheezing, doubled among elementary school children on high traffic days, as large numbers attend schools in close proximity to busy truck routes because of past land-use decisions.

The South Bronx has among the highest incidences of asthma hospital admissions in New York City, and a recent city survey of asthma in the South Bronx's Hunts Point district found an asthma prevalence rate in elementary school of 21 percent to 23 percent. The South Bronx is surrounded by several major highways, including Interstates 95, 87, 278 and 895. At Hunts Point Market alone, some 12,000 trucks roll in and out daily.

The study is a collaboration of NYU School of Medicine, the Robert F. Wagner Graduate School of Public Service, and four community groups The Point Community Development Corporation, Sports Foundation, Inc., We Stay/Nos Quedamos, Inc., and Youth Ministries for Peace & Justice Inc. Endorsed by Congressman Jose E. Serrano, the aim of the study was to examine the impact of industrial emissions on air quality and to direct policy initiatives. Serrano sponsored the press conference today where the findings were discussed.........

Posted by: Sean      Permalink         Source