Nerve marker: Injecting mice with a nerve-specific fluorescent probe makes the nerves glow under two wavelengths of light (middle, and top right). A tumor-specific probe highlights the tissue to be removed (bottom right).
Source: “Fluorescent peptides highlight peripheral nerves during surgery in mice”
Quyen T. Nguyen et al.
Nature Biotechnology online, February 6, 2011
Results: Researchers from the University of California, San Diego, developed a fluorescent peptide that binds specifically to nerve tissue. Two hours after it was injected into mice, all the animal’s peripheral nerves glowed when illuminated with a specific wavelength of light. The effect lasted for several hours. Researchers showed that the marker also identifies nerves in human tissue.
Why it matters: An easy way to visualize nerves should help surgeons avoid damaging them during delicate procedures. Nerve damage during surgery can lead to chronic pain and paralysis and, in the case of prostate operations, incontinence or erectile dysfunction. Existing methods of identifying nerves label only a single tract of nerves and can take days to do so.
Methods: To create nerve-specific probes, researchers first created a library of viruses that infect only bacteria and display different peptides, short chains of amino acids, on their coats. They then exposed nerve tissue to the viruses, looking for the peptide that bound most specifically to peripheral nerves. Attaching a fluorescent molecule to the target peptide created a glowing marker easily detectable under certain wavelengths of light.
Next Steps: Additional animal testing will be needed before the marker is ready to be tested in people. The technology has been licensed by Avelas Biosciences, a biotech startup, which is currently looking for private or industrial partnerships to develop it.
Home Heart Monitoring
An implanted sensor significantly reduces hospitalization rates for heart-failure patients.
Source: “Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: a randomised controlled trial”
William T. Abraham et al.
Lancet 377(9766): 658-666
Results: An implantable wireless sensor that measures fluid pressure in the pulmonary artery significantly reduced hospitalization rates in heart-failure patients. In a study of 550 patients at 64 centers across the country, those whose physicians used data from the sensor to monitor their health were 40 percent less likely to be hospitalized in the 15 months after receiving the implant than patients whose treatment was guided by observation of traditional measures such as weight and blood pressure. The pressure-sensing device transmits data wirelessly to a computer, where physicians can access the results and adjust the patient’s medication accordingly.
Why it matters: About two million people in the United States suffer from the type of heart failure targeted in this study. In these patients, changes in fluid pressure worsen congestion, triggering fluid buildup in other parts of the body. These pressure changes typically occur weeks or months before the symptoms get worse, but because existing methods of measuring this pressure are invasive, they are often performed only during a patient’s initial evaluation. The new device provides a way for physicians to monitor fluid pressure continually after a patient leaves the hospital. They can then fine-tune medications, preventing health crises that require additional hospitalization.
Methods: The device is made up of two metal loops that keep it in place inside the artery and a pressure transducer that records the flow of blood through the vessel. It is implanted using a simple catheter-based procedure. The device is activated when the patient lies on a pillow with a built-in receiver. The sensor then takes a reading and transmits the data to a computer for a physician’s review.
Next Steps: The company that makes the device, CardioMEMS, is seeking approval from the U.S. Food and Drug Administration. It also plans to integrate the sensor’s receiver into the patient’s cell phone. Physicians and patients will then have instant access to pressure data.