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mitotic component could be enhanced by various experimental aids.
In 1971, John O. and Jean C. Oberpriller, anatomists at the Univer-
sity of North Dakota School of Medicine in Grand Forks, reported that
small wounds in salamander hearts healed this way but required two
months. A year after that, the English edition of a book by Lev Pol-
ezhaev summarized several decades of Russian research, mainly on the
hearts of frogs and lizards. Pavel Rumyantsev, now at the Cytology In-
stitute of the USSR Academy of Sciences in Leningrad, had found in
1954 that newborn mammals (rats and kittens) could repair tiny punc-
ture wounds, and recently he has proved the same capacity in the atria,
or receiving chambers, of adult rat hearts. We even found a German
report of 1914 claiming that human babies had sometimes regenerated
small areas of their hearts damaged by diphtheria.
The Russians claimed some progress in extending this marginal native
healing. In the late 1950s, N. P. Sinitsyn had repaired large holes (up
to 16 square centimeters) in the hearts of dogs by covering the wounds
with patches made of muscle sheath, canvas, suede, or other materials.
Scar tissue still covered the outside, but the patch guided a thin layer of
new muscle fibers forming along its inner surface. Using dogs whose
wounds had already closed with scar tissue, Polezhaev then found he
could induce heart muscle to fill in part of the gap by cutting away the
scar and irritating the edges of the remaining cardiac muscle. Other
Soviet researchers enhanced the muscle cell proliferation a little more
with vitamins B1, B6, and B12, various drugs, extra RNA and DNA,
and heart tissue extracts or minces.
Despite such goads, heart regrowth was limited to very small injuries
or the border zone around larger ones, and it always took several weeks.
No one had even imagined that half a heart could restore its other half,
much less in a matter of hours. I could hardly wait until the next batch
of slides was ready.
They showed us an unprecedented
type of regeneration. Where the
missing part of the heart had been, a blastema formed in about two and
a half hours. We saw no evidence of dedifferentiation or mitosis in the
remaining heart-muscle cells, and indeed it would have been impossible
for the processes we'd already studied to make a blastema in such a short
time. Instead, the mass of primitive cells arose dramatically from the
blood.
As soon as the salamander heart is cut open, blood pools around the
wound and clots quickly, usuallyin about one minute, sealing the hole
like wet plaster. Almost immediately, the nearest red blood cells crack
open like eggs.
Their nuclei, surrounded by a thin coating of cytoplasm,
glide by some means yet unknown directly to the raw, fraved edge of the