The Bald Truth

If your 6-year-old chops off a salamander’s leg, a new limb will grow to take its place. If he chops off his own pinky finger, however, it’s time to look for specialized gloves. While the regeneration of appendages is commonplace among invertebrates and many reptiles and amphibians, the conventional wisdom has always been that mammals lack the knack. But a recent mouse experiment by Dr. George Cotsarelis, associate professor of dermatology, shows that our warm-blooded brethren have more healing power than anyone thought.

In a paper published in a May issue of Nature, Cotsarelis reported that wound healing created an “embryonic window” of opportunity in which genes thought to be active only in developing embryos were flipped back on in adult mice. This initiated a process in which stem cells were sent to the site of injury, leading to the creation of brand-new hair follicles. Proteins called wnts played an important role in governing the process, and when Cotsarelis and his colleagues increased wnt signaling, the number of new hair follicles doubled. The implication is that if researchers can manipulate these pathways, it could lead to novel treatments for scalp disorders, scarring apolecia, and possibly even male-pattern baldness.

The New Hooky

In the nearly bottomless annals of research on school absenteeism, four indicators consistently top the list of risk factors for the behavior: gender, race, socioeconomic status, and age. Specifically, young men from minority communities and poor backgrounds are at greater risk for missing class, which is in turn associated with higher rates of school dropout, teen pregnancy, and drug use. But a new study has identified another factor with even more predictive power: obesity.

Researchers from Penn and Temple examined the attendance records of more than a thousand 4th, 5th, and 6th graders enrolled in Philadelphia public schools. They found that overweight children were absent an average of 20 percent more often than their normal-weight classmates. According to lead author Andrew Geier, a psychology doctoral candidate at Penn, “What’s keeping them from school, more than health issues, is the stigma and the bullying that accompanies being overweight.” The findings were reported in the August issue of the journal Obesity.

Nurse Migration

Although the United States employs almost one-fifth of the world’s professional nurses, it is well known that there aren’t enough to meet the country’s total demand. Some experts forecast that the present shortage will grow to a deficit of 800,000 nurses by 2020. And if current trends continue, according to Dr. Linda Aiken, the Claire M. Fagin Leadership Professor of Nursing at Penn, the U.S. shortage may hit developing countries the hardest.

In a study in the June issue of Health Services Research, Aiken reported that nurse immigration to the U.S. has tripled since 1994. In 2005, some 15,000 foreign-born nurses passed the American licensing exam, most of them from developing nations that can scarcely afford to lose skilled medical workers. Somewhat fewer than half of foreign-born nurses pass the exam on the first try, compared with 87 percent of American nurses.

Meanwhile, American nursing schools are not producing enough graduates to satisfy current or estimated future needs. Higher-education costs have risen sharply in recent years, and whereas many other national governments fully fund the training of nursing students, the U.S. government does not. “Investments by hospitals in nursing education have helped nursing schools expand enrollments substantially over the past five years,” Aiken writes, but not enough to offset the larger trend.

Unless the production capacity of domestic nursing schools can be ramped up, Aiken concludes, the United States’ position as the world’s largest importer of nurses may jeopardize health-care delivery on both a national and global scale. 


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