Standing outside the low, gray industrial building, she watched as horses went in one side and, about 15 minutes later, a worker appeared on the other end, holding a head, neurons and all.“It was precisely as revolting as it sounds,” she says.Other cells, like those in the adult brain and nervous system, have been viewed as more like the Mona Lisa. Spalding, once a postdoc at the Karolinska Institute in Stockholm, Sweden and now a professor there, knew there were tantalizing hints that the adult hippocampus—a seahorse-shaped region deep in the brain that is important for memory and learning—could regenerate neurons.
“We found stem cells in the hippocampus of adult mice and rats that could create new neurons,” Gage says.
It was groundbreaking work, but at the time not everyone was convinced of its importance.
The bomb pulse has been declining since the 1963 above-ground test ban treaty, creating a sort of clock they could exploit.
By determining how many radioactive carbon atoms a cell contained, Spalding and Frisén hoped they could calculate its birthdate. Spalding’s curiosity eventually leading her to a slaughterhouse on the outskirts of Stockholm.
What was once a seven-proton nitrogen became a six-proton carbon.
But unlike most carbon atoms, which have six protons six and neutrons, this radioactive carbon, known as C, scientists use a technique called mass spectrometry, which sorts atoms by weight.
“In order for this to have significance, we needed to know whether this occurred in humans.” To identify dividing cells in mice and rats, Gage had been using a molecule known as bromodeoxyuridine, or Brd U.
Brd U is a synthetic nucleoside that can be incorporated into newly synthesized DNA in place of the standard nucleoside thymidine, the T in ATCG.
Their work has been so fruitful that it could provide them with a lifetime worth of projects.
But she and her collaborators can’t waste any time.
Spalding would then spend hours chipping away to extract the necessary cells, a grisly procedure that was just the first in a decade-long stretch of hurdles she had to surmount.