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RED CELLS
From the Department of Pharmacology and Physiology,
University of Rochester School of Medicine and Dentistry and Department
of Chemical Engineering, University of Rochester, Rochester, New York.
During maturation of the red blood cell (RBC) from the nucleated
normoblast stage to the mature biconcave discocyte, both the structure
and mechanical properties of the cell undergo radical changes. The
development of the mechanical stability of the membrane reflects
underlying changes in the organization of membrane-associated cytoskeletal proteins, and so provides an assessment of the time course
of the development of membrane structural organization. Membrane
stability in maturing erythrocytes was assessed by measuring forces
required to form thin, tubular, lipid strands (tethers) from the
surfaces of mononuclear cells obtained from fresh human marrow samples,
marrow reticulocytes, circulating reticulocytes, and mature
erythrocytes. Cells were biotinylated and manipulated with a
micropipette to form an adhesive contact with a glass microcantilever, which gave a measure of the tethering force. The cell was withdrawn at
controlled velocity and aspiration pressure to form a tether from the
cell surface. The mean force required to form tethers from marrow
reticulocytes and normoblasts was 27 ± 9 pN, compared to
54 ± 14 pN for mature cells. The energy of dissociation of the bilayer from the underlying skeleton increases 4-fold between the
marrow reticulocyte stage and the mature cell, demonstrating that the
mechanical stability of the membrane is not completely established
until the very last stages of RBC maturation. This article has been cited by other articles:
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| Copyright © 2001 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
