Biomedical Beat - A monthly digest of research news from NIGMS

IN THIS ISSUE . . .
August 20, 2008

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The National Institute of General Medical Sciences (NIGMS), one of the National Institutes of Health, supports all research featured in this digest. Although only the lead scientists are named, coworkers and other collaborators also contributed to the findings. To read additional news items, visit NIGMS News. To check out free NIGMS publications, go to the order form.

Cool Movie: Walking the Line

When we walk, muscles and nerves interact in intricate ways to let us take a step. This simulation, which is based on data from a 6-foot-tall man, shows what happens. When we walk, muscles and nerves interact in intricate ways to let us take a step. This simulation, which is based on data from a 6-foot-tall man, shows what happens.
This simulation shows what happens when we walk

Full-screen version

When we walk, muscles and nerves interact in intricate ways to let us take a step. This simulation, based on movement data from a 6-foot-tall man and generated using computational modeling, shows what happens. Red indicates that a muscle has received a signal from the nervous system to contract, and blue shows that the muscle is relaxed and receiving no signal. The simulation and the software behind it one day could aid athletic coaches and doctors in understanding how injuries that disrupt motor signals can cause movement disorders. Courtesy of computational biomechanists Chand John and Eran Guendelman, Stanford University.

The NIH Roadmap for Medical Research supports this work.


Neuromuscular biomechanics lab home page

Predicting Sepsis Survival in Children

A protein can help predict the survival of children with septic shock.
A protein can help predict the survival of children with septic shock.

About 4,000 children in the United States die each year from septic shock, which results from uncontrolled infection. As the infection spirals out of control, the immune system secretes the protein IL-8 to serve as a signal for the recruitment of more infection-fighting cells. Pediatric critical care specialist Hector Wong at Cincinnati Children's Hospital Medical Center has now found that blood levels of IL-8 can be used to predict survival of children with septic shock. By using IL-8 levels as a diagnostic tool, doctors may be able to screen patients to guide treatment and the development of new therapies.

Full story
Wong home page
Article abstract (from the August 1 issue of the American Journal of Respiratory and Critical Care Medicine)

Sensing Slight Temperature Changes

In a two-way test, larvae choose an environment with a cooler temperature. Courtesy of Young Kwon and Craig Montell.
In a two-way test, larvae choose an environment with a cooler temperature. Courtesy of Young Kwon and Craig Montell.
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Many animal species prefer living in a limited range of temperatures and can detect subtle changes within that range. Biologist Craig Montell and collaborators at Johns Hopkins School of Medicine have found that fruit fly larvae use a protein called the TRPA1 channel to detect single degree changes within their comfort range of 64 to 75 degrees Fahrenheit. TRPA1 seems to work by amplifying the physiological effect of small changes, allowing larvae to sense and adapt to slightly different temperatures. Montell's work also raises the possibility that a similar process may exist in mammals, enabling them to notice small changes in internal temperature.

NIH's National Eye Institute also supported this work.

Full story
Montell home page
Article abstract (from the July 27 online issue of Nature Neuroscience)

Circadian and Metabolic Proteins Linked

Circadian rhythms respond to light and darkness in an organism's environment.
Circadian rhythms respond to light and darkness in an organism's environment.
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A system of biological clocks, called circadian rhythms, keeps our bodies ticking. Disrupting these rhythms can lead to serious health problems, including obesity and cancer. Scientists know that an essential component of the circadian machinery is the protein CLOCK. Paolo Sassone-Corsi and his colleagues at the University of California, Irvine, now have found that CLOCK is counterbalanced by a metabolic protein called SIRT1, which senses how much energy cells use. The research suggests that proper sleep and diet may help maintain the equilibrium of these two proteins and could explain why lack of sleep has been shown to increase hunger.

Full story
Circadian rhythms fact sheet
Sassone-Corsi home page
Article abstract (from the July 25 issue of Cell)

Got Milk?

Sarah Tishkoff.
Sarah Tishkoff.

Watch the video interview with Sarah Tishkoff.

The enzyme lactase allows mammals to digest milk, but it's usually shut down after weaning. University of Pennsylvania geneticist Sarah Tishkoff is tracing the genetic mutation that allows adult humans to continue processing milk. Her research on lactose tolerance led her to Africa, where she has worked with more than 40 different ethnic groups. Tishkoff found that the emergence of domesticating cattle occurred around the same time that a mutation allowing for the persistence of lactase arose. This co-evolution allowed dairying cultures to digest milk and gave them a selective advantage.

Tishkoff home page
Article abstract (from the January 2007 issue of Nature Genetics)