Polarization-optical investigation (topo-optical analysis) of the structure of the human erythrocyte glycocalyx. Influence of pH, ionic strength and diamide-induced spectrin cross linking |
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Authors: | K J Halbhuber H Oehring M Gliesing D Stibenz |
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Institution: | Department of Histochemistry, Friedrich Schiller University, Jena, GDR. |
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Abstract: | The value of membrane anisotropy after fixation and topo-optical analysis of erythrocytes stained with toluidine blue is a measure for the degree of spatial order of the dyestuff-binding acidic residues of the glycocalyx and thus a parameter for the characterization of the glycocalyx structure. Lowering the pH value and/or the ionic strength of the staining medium results in a decrease of membrane anisotropy indicating a lower order of the anionic residues. In agreement with the findings of other authors this phenomenon seems to be connected with an expansion of the glycocalyx. Diamide-induced oxidative crosslinking of spectrin before fixation and staining with toluidine blue at physiological pH and ionic strength also results in a decreased anisotropy. This indirect influence on the glycocalyx structure may be caused by an increase of the charge density within the glycocalyx due to a diamide-induced rearrangement of the membrane skeleton and of the transmembrane proteins bound to it. |
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