A biotech company says it put dopamine-making cells into people’s brains

In an important test for stem-cell medicine, a biotech company says implants of lab-made neurons introduced into the brains of 12 people with Parkinson’s disease appear to be safe and may have reduced symptoms for some of them.

The added cells should produce the neurotransmitter dopamine, a shortage of which is what produces the devastating symptoms of Parkinson’s, including problems moving.