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Archive - Aug 9, 2014

"Game-Changer" in Nerve Repair

A multicenter study including University of Kentucky researchers has found that a new nerve repair technique yields better results and fewer side effects than other existing techniques. Traumatic nerve injuries are common, and when nerves are severed, they do not heal on their own and must be repaired surgically. Injuries that are not clean-cut – such as saw injuries, farm equipment injuries, and gunshot wounds – may result in a gap in the nerve. To fill these gaps, surgeons have traditionally used two methods: a nerve autograft (bridging the gap with a patient's own nerve taken from elsewhere in the body), which leads to a nerve deficit at the donor site; or nerve conduits (synthetic tubes), which can cause foreign body reactions or infections. The prospective, randomized study, conducted by UK Medical Director of Hand Surgery Service Dr. Brian Rinker and others, compared the nerve conduit to a newer technique called a nerve allograft. The nerve allograft uses human nerves harvested from cadavers. The nerves are processed to remove all cellular material, preserving their architecture while preventing disease transmission or allergic reactions. Participants with nerve injuries were randomized into either conduit or allograft repair groups. Following the surgeries, independent blind observers performed standardized assessments at set time points to determine the degree of sensory or motor recovery. The results of the study suggested that nerve allografts had more consistent results and produced better outcomes than nerve conduits, while avoiding the donor site morbidity of a nerve autograft. Dr. Rinker, a principal investigator of the study, describes it as a "game-changer.

Scientists Use CRISPR Tool to Silence HPV Genes in Cervical Carcinoma Cells

Researchers have hijacked a defense system normally used by bacteria to fend off viral infections and redirected it against the human papillomavirus (HPV), the virus that causes cervical, head and neck, and other cancers. Using the genome editing tool known as CRISPR (see image), the Duke University researchers were able to selectively destroy two viral genes responsible for the growth and survival of cervical carcinoma cells, causing the cancer cells to self-destruct. The findings, appearing online August 6, 2014 in the Journal of Virology, give credence to an approach only recently attempted in mammalian cells, and could pave the way toward antiviral strategies targeted against other DNA-based viruses like hepatitis B and herpes simplex. "Because this approach is only going after viral genes, there should be no off-target effects on normal cells," said Bryan R. Cullen, Ph.D., senior study author and professor of molecular genetics and microbiology at Duke University School of Medicine. "You can think of this as targeting a missile that will destroy a certain target. You put in a code that tells the missile exactly what to hit, and it will only hit that, and it won't hit anything else because it doesn't have the code for another target." The CRISPR targeted system was only discovered a decade ago. Looking at the genomes of different types of bacteria, researchers had noticed long stretches where the same genetic sequence was repeated. In between these repeats lay DNA sequences that differed from bacteria to bacteria. Scientists figured out that these unique sequences -- known as clustered regularly interspaced short palindromic repeats or CRISPR -- were derived from viruses that had previously infected the bacteria.