Brain Repair Companies Sharpen Their Drills. “A local anesthetic, a small drill-hole in the

skull and a syringe full of new cells may one day be all it takes to

repair brain damage.” Regenerating damaged tissue with neural stem cells offers promise to reverse the deficits of stroke, Parkinson’s Disease, Alzheimer’s etc. Tissue transplanted from aborted fetuses has been used successfully in reversing the worst symptoms of a handful of Parkinson’s Disease patients, but the ethical problems caused by depending on fetal stem cells has led to a quest for other sources, including “immortalized” human cell lines, nonhuman mammalian sources and, recently, cadavers. Companies are lining up to commercialize the approach once it is clear it is safe and effective. Here’s a primer on stem cells from the National Institutes of Health; and information from the American Association for the Advancement of Science on stem cell research and applications.