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H. Mussauer V.L. Sukhorukov A. Haase U. Zimmermann 《The Journal of membrane biology》1999,170(2):121-133
The interaction of human red blood cells (RBCs) with diethylenetriamine-pentaacetic acid (DTPA) or its Gd-complex (Magnevist,
a widely used clinical magnetic resonance contrast agent containing free DTPA ligands) led to the following, obviously interrelated
phenomena. (i) Both compounds protected erythrocytes against electrohemolysis in isotonic solutions caused by a high-intensity
DC electric field pulse. (ii) The inhibition of electrohemolysis was observed only when cells were electropulsed in low-conductivity
solutions. (iii) The uptake of Gd-DTPA by electropulsed RBCs was relatively low. (iv) (Gd-) DTPA reduced markedly deformability
of erythrocytes, as revealed by the electrodeformation experiments using high-frequency electric fields. Taken together, the
results indicate that (Gd-) DTPA produce stiffer erythrocytes that are more resistant to electric field exposure. The observed
effects of the chelating agents on the mechanical properties and the electropermeabilization of RBCs must have an origin in
molecular changes of the bilayer or membrane-coupled cytoskeleton, which, in turn, appear to result from an alteration of
the ionic equilibrium (e.g., Ca2+ sequestration) in the vicinity of the cell membrane.
Received: 19 January 1999/Revised: 1 April 1999 相似文献
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Electrical breakdown of erythrocytes induces hemoglobin release which increases markedly with decreasing conductivity of
the pulse medium. This effect presumably results from the transient, conductivity-dependent deformation forces (elongation
or compression) on the cell caused by Maxwell stress. The deformation force is exerted on the plasma membrane of the cell,
which can be viewed as a transient dipole induced by an applied DC electric field pulse. The induced dipole arises from the
free charges that accumulate at the cell interfaces via the Maxwell-Wagner polarization mechanism. The polarization response
of erythrocytes to a DC field pulse was estimated from the experimental data obtained by using two complementary frequency-domain
techniques. The response is very rapid, due to the highly conductive cytosol. Measurements of the electrorotation and electrodeformation
spectra over a wide conductivity range yielded the information and data required for the calculation of the deformation force
as a function of frequency and external conductivity and for the calculation of the transient development of the deformation
forces during the application of a DC-field pulse. These calculations showed that (i) electric force precedes and accompanies
membrane charging (up to the breakdown voltage) and (ii) that under low-conductivity conditions, the electric stretching force
contributes significantly to the enlargement of ``electroleaks' in the plasma membrane generated by electric breakdown.
Received: 12 December 1997/Revised: 13 March 1998 相似文献
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BACKGROUND: Electropermeabilization is widely used for introduction of DNA and other foreign molecules into eukaryotic cells. However, conditions yielding the greatest molecule uptake and gene expression can result in low cell survival. In this study, we assessed the efficiency of trehalose for enhancing cell viability after excessive electropermeabilization. This disaccharide was chosen because of its capability of stabilizing cell membranes under various stressful conditions, such as dehydration and freezing. MATERIALS AND METHODS: Various mammalian cell lines were electropermeabilized by single exponentially decaying electric pulses of few kV/cm strength and of several-microsecond duration. Propidium iodide (PI) and a plasmid encoding green fluorescent protein (GFP), respectively, served as reporter molecules. The effects of trehalose on PI-uptake, GFP gene expression, transfection yield, and short- and long-term viability were analyzed by flow cytometry and electronic cell counting. RESULTS: The substitution of inositol by trehalose in pulse media protected cells against field-induced cell lysis. The protection effect saturated at about 40-50 mM trehalose. Transfection yield and gene expression were not significantly affected by trehalose. But the transfection efficiency was generally higher in the presence of trehalose, mainly because of the increased cell survival. CONCLUSIONS: We demonstrated that trehalose-substituted media are superior to standard trehalose-free pulse media for improving cell survival and achieving higher electrotransfection efficiency. 相似文献
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