Herbert J.
Meiselman was recognized as the recipient of the Poiseuille
Gold Medal at the 13th Congress. During his Professorship
at USC, Herb became one of the most prolific and important
experimental scientists in the field of blood rheology. His
studies encompassed many aspects of red blood and leukocyte
cell rheology, exploring the factors underlying the flow and
deformation of red and white cells (e.g. cell deformation,
aggregation, viscoelasticity). Much of his work has been
concerned with the changes in cellular mechanics that occur
in the neonatal and in the abnormal pathophysiological
circulation and result in clinically relevant phenomena.
This has taken him into fields as diverse as the effect of
dextran, polyvinylpyrrolidone and other polymers on red cell
rheology (important for subsequent work on the mechanism of
red cell aggregation), hemorhological factors (including
those of polymorphonuclear leukocytes) in cerebral ischemia,
coronary artery disease and aspects of blood cell
abnormalities in diabetes mellitus, sickle cell disease and
hypertension.
In subsequent years, his laboratory undertook a major study
of the mechanism underlying red cell aggregation by
polymers. It has been shown that the depletion model rather
than the bridging model is in qualitative and quantitative
agreement with the measured cell-cell affinity and red cell
aggregation. This model proposes that RBC cell aggregation
occurs as a result of a lower localized protein or polymer
concentration near the cell surface as compared with the
suspending medium (i.e., relative depletion near the cell
surface). This exclusion of macromolecules near the cell
surface leads to an osmotic gradient and thus depletion
interaction. As with the bridging model, disaggregation
forces are electrostatic repulsion, membrane strain, and
mechanical shearing. Herb intends to apply this model to
unresolved aspects of human red cell aggregation, such as
the more than 100% increase of aggregation for old versus
young red cells when suspended in autologous plasma or
polymer solutions (Clinical
Hemorheology 13:575-592, 1993),
or the reduced aggregation of neonatal red cells in plasma
or in polymer solutions (Pediatric
Research, 18:1356-1360, 1984).
Application of this model may also be of potential value in
human disease.His award lecture
was titled "In vitro and in vivo aspects of red blood cell
aggregation".
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