August 2007
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Children's latest research
Newborn Medicine: A simpler way to check catheter placement
Otolaryngology: Neural stem cells may help regrow the cochlea
Hematology/Oncology: A faster recovery from marrow transplants
Resident invents a glowing catheter
The placement of central catheters, which deliver lifesaving nutrition and medicine to the most premature infants, is a "blind" procedure. The catheter is typically inserted in the forearm or ankle and advanced until it reaches a location near the heart. Only an X-ray can reveal whether the catheter has gone astray, veering too close to the heart, into the neck or even winding back down the arm. Adjustments are often required, leading to delays, more X-rays and exposure of the infant to more radiation."I thought to myself, there must be a better way to do this," says Farhad Imam, MD, PhD, a clinical fellow in Newborn Medicine at Children's Hospital Boston, who witnessed several "misroutings" as a resident in the Neonatal Intensive Care Unit (NICU). Imam's solution was intuitive: He threaded a central catheter with an illuminated fiber-optic wire to make it glow, allowing its progress through the body to be tracked with the naked eye. After night shifts during his residency and the first year of his NICU fellowship, Imam spent afternoons testing his design on rabbits. The catheter's red gleam was visible through tissue—and even fur.
Initially funded by a Lovejoy Research Award for residents, Imam is now supported by a Massachusetts Technology Transfer Center grant and he's contracted with two engineering firms to help build a prototype light-guided catheter over the next year. "The catheter will be most readily usable in newborns," he says, "but it should also work in children and possibly in adults."
Jacqueline Armstrong and Monique Yoakim-Turk of Children's Intellectual Property Office helped Imam file a patent, recognizing that a light-guided catheter could save money and time by replacing the current technique. "Residents have cool ideas," says Yoakim-Turk. "They're new and tend to question what others don't anymore."
First steps toward a living cochlear implant
Most cases of deafness are caused by the dysfunction or death of cells in the cochlea, the snail-shell-shaped structure in the inner ear. Douglas Cotanche, PhD, a researcher in Otolaryngology, now reports that his lab has grown all the assorted cell types in the cochlea from just one source: neural stem cells. The study was published online June 20 by the journal Hearing Research.Neural stem cells were first isolated from mice in 1998 by Evan Snyder, MD, PhD, formerly of Children's Department of Neurology. Cotanche's team implanted the cells deep inside the sound-damaged cochleas of guinea pigs and mice. Six weeks later, the cells had migrated throughout the cochlea and formed satellite cells, spiral ganglion cells and Schwann cells, which make up the cochlea's nervous tissue, as well as the hair cells and supporting cells of the organ of Corti (the actual hearing organ). "Getting these cells to integrate into the damaged ear and make the variety of cochlear cell types is a big step," says Cotanche.
The researchers couldn't show complete rebuilding of the cochlea, but they believe that with more time and more stem cells, most of the cochlea could be repopulated. Cotanche's next goal is to implant human neural stem cells in animals and test whether the new cochlear cells connect with the auditory nerve and the brain, and whether they respond to sound stimulation—in other words, whether they restore hearing.
Boosting blood stem cells Zebrafish show the way
By systematically screening more than 2,500 chemicals in zebrafish, Leonard Zon, MD, Trista North, PhD, and Wolfram Goessling, MD, PhD, of Children's Stem Cell Program, have identified an available drug that ramps up production of blood stem cells, helping patients recover immune function more quickly after chemotherapy or bone marrow transplants. The drug, a derivative of prostaglandin E2, may be tested as early as next year in patients undergoing cord blood transplant for leukemia. The paper appeared in the June 21 issue of Nature.
