Ten
The Lazarus Heart
Like Columbus, scientists sometimes stumble upon new continents
when merely seeking a quicker trade route. Our research group had this
good fortune in 1973.
We'd gone back to basics after learning how to dedifferentiate frog
red blood cells and start regeneration in rat limbs. We decided to study
nucleated red cells in a variety of creatures, hoping for leads toward
better regrowth in mammals. Although their circulating erythrocytes
have no nuclei, even mammals have young red cells, with nuclei, form-
ing in the bone marrow. After severe bleeding, up to a fifth of those in
the bloodstream may be immature nucleated types, as the marrow rushes
them into service to make up for the loss. We surveyed the effect of
direct current on red cells from fish, amphibians, reptiles, and birds. All
of the cells responded, but in a different way for each species. We de-
cided to have a more detailed look at the largest and hence most easily
studied red blood cells available, those of our old friend Triturus vir-
idescens, the common green newt.
A newt is so small that you can't just poke a needle into one of its
veins and take a blood sample. The only practical way to get pure blood
is to anesthetize the animal, slice open its chest, cut its heart in two,
extract the blood with a pipette, and throw away the carcass.
As the phrase goes, we "harvested" blood from three newts each week
by this method. One day, when Sharon Chapin had finished the chore,
she asked me, "What would happen if I sewed these animals up?" I
answered that, because their hearts had been destroyed, they would die
within minutes, with or without sutures, from lack of oxygen to the