Using Lomb periodogram analysis we have quantified variations in the periph
eral neutrophil and platelet counts of the cyclical neutropenia animal mode
l-the grey collie. We found that the amplitudes of the oscillations in thes
e two cell lineages vary concomitantly, Further, the power spectrum and the
shape of the oscillations in the absolute neutrophil counts vary together
with the amplitude of the oscillations. As the amplitude of the oscillation
s increases, the height of the second subharmonic increases, giving rise to
a distorted oscillation with two peaks per cycle. The particular dynamics
of the absolute neutrophil counts can be reproduced by a combination of a d
elayed peripheral feedback, representing the peripheral control of granulop
oiesis through granulocyte colony stimulating factor, together with a sinus
oidal input representing an oscillatory input from the pluripotential stem
cells to the granulocytic lineage. The same pluripotential stem cell input
is probably responsible for the sinusoidal oscillations observed in the oth
er cell lineages. (C) 1999 International Society for Experimental Hematolog
y. Published by Elsevier Science Inc.