Biophysical responses of red cell-membrane systems to very low concentrations of inorganic mercury |
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Authors: | Howard C Mel Thomas A Reed |
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Institution: | (1) Biology and Medicine Division, Lawrence Berkeley Laboratory, Department of Biophysics and Medical Physics, University of California, 94720 Berkeley, California |
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Abstract: | Changes in red blood cellsize, deformability, andosmotic fragility are indicators of altered condition and/or altered regulatory processes at the whole cell and membrane levels. An agent,
such as HgCl2, that brings about specific changes of this kind can therefore serve as a selective probe of such cell condition and regulatory
state. Conversely, for a health-threatening agent “active” in this way, the cell-membrane responses serve to clarify the more
fundamental bases of its toxicity, as well as to permit identification and characterization of its early and low-level actions
on living systems. Taking advantage of recent advances in the technique of “resistive pulse spectroscopy,” we present a coordinated
study of these three interrelated biophysical properties for the interactions of HgCl2 with human red cells. We thereby are able to extend previous studies of this kind into domains of shorter time (instantaneous
exposures), lower level exposures (down to 10−9
M, well below the level of acute human toxicity), as well as to additional kinds of responses (e.g., “dynamic osmotic hemolysis”).
For conditions ranging from 10−4 to 10−9
M in HgCl2, for instantaneous to 90-min-incubated exposures, for medium osmolarities from 120 to 300, the matrix of observed cell responses
includes relative swelling as well as shrinkage, changes in deformability, and both enhancement of and protection against
osmotic hemolysis. Some unexpected short-term effects of time and temperature of storage of blood cell stock samples, with
respect to increasing and decreasing osmotic fragility, are also reported. These apparently disparate results are interpreted
in terms of mercury interactions with cell and membrane SH groups, and a reasonable rationale is presented for most of the
responses in terms of disruption of passive and active Na+−K+, gradient controls, plus interactions with cellular proteins. |
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Keywords: | Red cell membranes and mercury mercury effects on red cell-membranes size of red blood cells deformability of red blood cells osmotic fragility of red blood cells hemolysis of red blood cells rheology of red blood cells resistive pulse spectroscopy of red blood cells membranes of red blood cells |
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