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Molecular/cell level of gas exchange function assumes the accurate measurement of erythrocyte characteristics and rate constants concerning to molecules involved into the CO

Whereas commercially available hematological analyzers measure volume of individual platelets, angle-resolved light-scattering provides unique ability to additionally measure their shape index. We utilized the scanning flow cytometer to measure light-scattering profiles (LSPs) of individual platelets taken from 16 healthy donors and the solution of the inverse light-scattering problem to retrieve the volume and shape index of each platelet. In normal conditions, the platelet shape index distribution (PSID) demonstrates three peaks, which relate to resting, partially activated, and fully activated platelets. We developed an algorithm, based on fitting PSID by a sum of three peak functions, to determine the percentage, mean platelet shape index, and distribution width of each platelet fraction. In total, this method gives eight additional parameters of platelet morphology and function to be used in clinical hematological analysis. We also stimulated the platelets with adenosine diphosphate (ADP) and measured the dependence of equilibrium PSID, including the total percentage of activated platelets, on ADP concentration. © 2016 International Society for Advancement of Cytometry.

A mathematical model of erythrocyte lysis in isotonic solution of ammonium chloride is presented in frames of a statistical approach. The model is used to evaluate several parameters of mature erythrocytes (volume, surface area, hemoglobin concentration, number of anionic exchangers on membrane, elasticity and critical tension of membrane) through their sphering and lysis measured by a scanning flow cytometer (SFC). SFC allows measuring the light-scattering pattern (indicatrix) of an individual cell over the angular range from 10 degrees to 60 degrees . Comparison of the experimentally measured and theoretically calculated light scattering patterns allows discrimination of spherical from non-spherical erythrocytes and evaluation of volume and hemoglobin concentration for individual spherical cells. Three different processes were applied for erythrocytes sphering: (1) colloid osmotic lysis in isotonic solution of ammonium chloride, (2) isovolumetric sphering in the presence of sodium dodecyl sulphate and albumin in neutrally buffered isotonic saline, and (3) osmotic fragility test in hypotonic media. For the hemolysis in ammonium chloride, the evolution of distributions of sphered erythrocytes on volume and hemoglobin content was monitored in real-time experiments. The analysis of experimental data was performed in the context of a statistical approach, taking into account that parameters of erythrocytes vary from cell to cell.

The use of a scanning flow cytometer (SFC) to study the evolution of monomers, dimers and higher multimers of latex particles at the initial stage of the immunoagglutination is described. The SFC can measure the light-scattering pattern (indicatrix) of an individual particle over an angular range of 10-60 deg. A comparison of the experimentally measured and theoretically calculated indicatrices allows one to discriminate different types of latex particles (i.e. monomers, dimers, etc.) and, therefore, to study the evolution of immunoagglutination process. Validity of the approach was verified by simultaneous measurements of light-scattering patterns and fluorescence from individual polymer particles. Immunoagglutination was initiated by mixing bovine serum albumin (BSA)-covered latex particles (of 1.8 um in diameter) with anti-BSA IgG. The analysis of experimental data was performed on the basis of a mathematical model of diffusion-limited immunoagglutination aggregation with a steric factor. The steric factor was determined by the size and the number of binding sites on the surface of a latex particle. The obtained data are in good agreement with the proposed mathematical modeling., 12 pages, 6 figures