title: Scanning electron microscopical characterization of La3+- and concanavalin A-induced aggregations of untreated and neuraminidase-treated human erythrocytes.
abstract: The aggregates of washed control and NANAse-treated human red blood cells (RBC) were characterized by scanning electron microscopy (SEM). Aggregation of RBC was performed under well-defined laminar shear conditions (78.6 S-1) in a horizontally arranged coaxial cylinder system. Generally, with increasing La3+ concentration in the PBS the aggregates became larger and the contact between the RBC "more intensive". This was evidenced by more cells per aggregate, an enlargement of contact areas, a change of cell shape in the contact region and signs of fusion phenomena. Especially at high La3+ concentrations on the cell surface of treated and untreated RBC some deposits were seen by SEM which are possibly La3+- phosphate precipitates. Neuraminidase treatment promoted the described La3+ effects. Concanavalin A-induced RBC agglutinates were different from the more spherical former ones and showed a network-like morphology. The conclusions drawn on the basis of light and scanning electron microscopical investigations are confirmed by quantitative values of an aggregation index estimated in parallel.
mesh_terms: D002449:Cell Aggregation / Q000187:drug effects*; D003208:Concanavalin A / Q000494:pharmacology*; D004912:Erythrocytes / Q000648:ultrastructure*; D006801:Humans; D007811:Lanthanum / Q000494:pharmacology*; D008297:Male; D008855:Microscopy, Electron, Scanning; D009439:Neuraminidase / Q000494:pharmacology*
chemical_list: D003208:Concanavalin A; D007811:Lanthanum; D009439:Neuraminidase