Researchers report first evidence of cellular ‘catch bonds’

An article published this week in the journal Nature provides the first experimental evidence for an unusual molecular bonding mechanism that could explain how certain cells adhere to surfaces such as blood vessel walls under conditions of mechanical stress. Known as “catch bonds,” the adhesion mechanism displays surprising behavior, prolonging rather than shortening the lifetimes of bonds between specific molecules as increasing force is applied. Proposed theoretically nearly 15 years ago, catch bonds could help explain how the body regulates the activity of white blood cells, which must flow freely through blood vessels — yet bond to injury sites despite blood flow forces.

Intrusive emotional memories make rats forget recently learned information

People who undergo emotional trauma, such as wartime combat, typically have disturbing memories of experiences that can haunt them for the rest of their lives. These intense emotional memories often intrude into their daily lives, interfering with their ability to concentrate and learn new information. Researchers at the University of South Florida and James A. Haley Veterans’ Hospital have shown for the first time that a remote, fear-provoking memory disrupts the ability of rats to remember new information ? a symptom common in people with post-traumatic stress disorder (PTSD). The animal model they developed may eventually lead to improved drug treatments for people with anxiety disorders such as PTSD.

A cookie less per day keeps the fat away

Eating 100 fewer calories a day?roughly three bites of a fast-food hamburger?could prevent the 1.8 to 2.0 pounds that the average person gains per year, according to new estimates by James Hill and colleagues. Their article appears in the 7 February issue of the journal Science, published by the American Association for the Advancement of Science.

Long-life contact lenses

A Texas scientist has discovered that a special metal coating could allow contact lens wearers to keep their lenses in for longer periods of time. Coating contacts with a one-molecule-thick layer of selenium, an antibacterial metal, keeps them bacteria-free for at least two months, says Ted Reid of Texas Tech University Health Sciences Center in Lubbock. Although selenium can be toxic to humans in large quantities, these lenses would apparently be safe, with less selenium than you’d find in an average lunch. Reid hopes the coating could be used on other internal devices, like heart valves and catheters, and even suggests selenium-coated molecules could be used to keep people exposed to HIV from becoming infected. In other eye news, new eye-tracking software developed by scientists at Cambridge University could help computer users with disabilities write more quickly, accurately, and comfortably than before.

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