Photometric measurements of red blood cell aggregation: light transmission versus light reflectance

Red blood cell (RBC) aggregation is the reversible and regular clumping in the presence of certain macromolecules. This is a clinically important phenomenon, being significantly enhanced in the presence of acute phase reactants (e. g., fibrinogen). Both light reflection (LR) and light transmission (LT) from or through thin layers of RBC suspensions during the process of aggregation are accepted to reflect the time course of aggregation. It has been recognized that the time courses of LR and LT might be different from each other. We aim to compare the RBC aggregation measurements based on simultaneous recordings of LR and LT. The results indicate that LR during RBC aggregation is characterized by a faster time course compared to simultaneously recorded LT. This difference in time course of LR and LT is reflected in the calculated parameters reflecting the overall extent and kinetics of RBC aggregation. Additionally, the power of parameters calculated using LR and LT time courses in detecting a given difference in aggregation are significantly different from each other. These differences should be taken into account in selecting the appropriate calculated parameters for analyzing LR or LT time courses for the assessment of RBC aggregation. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3251050

Effect of sulfite on red blood cell deformability ex vivo and in normal and sulfite oxidase-deficient rats in vivo

The effect of sulfite, a widely used food additive, on red blood cell deformability ex vivo and in vivo was investigated. Ex vivo experiments were conducted in human blood exposed to sulfite (5, 10 and 20 mM). In vivo experiments were carried out in sulfite oxidase-competent (SOXC) and sulfite oxidase-deficient (SOXD) rats. In the in vivo experiments, sulfite was administered in the form of sodium metabisulfite (Na2S 2O5, 25 mg/kg/day) via drinking water. Vitamin E dissolved in olive oil at a dose of 50 mg/kg was administered by gastric gavages. Red blood cell (RBC) deformability was determined at various fluid shear stresses using an ektacytometer. Ex vivo sulfite exposure to RBC did not affect RBC deformability. In the in vivo experiments, although RBC deformability was not affected by sulfite treatment in SOXD rats, it was found to be significantly increased in SOXC rats. Vitamin E treatment in combination with sulfite caused impairment in RBC deformability in both SOXC and SOXD rats. We suggest that sulfite needs to be oxidized in order to improve RBC deformability. © Springer-Verlag 2005

EPO or PlacEPO? Science versus Practical Experience

Recombinant human erythropoietin (rHuEPO) is an agent commonly used by with the aim to improve performance in endurance sports. However, the community continues to debate the risks, benefits and its mechanism of when used as a doping agent. This paper provides a brief overview on the cons of rHuEPO use, as discussed by a group of scientist with diverse at the 17th Conference of the European Society for Clinical Hemorheology Microcirculation in Pecs, Hungary. Among multiple topics, panel members challenged the common belief that the increased circulating hemoglobin concentration is the simple key to the improved sporting performance. hemorheologists developed the concept of optimal hematocrit (Hct), a Hct that represents the optimal balance between the oxygen transport blood and blood viscosity. While guideline-directed transfusion therapy advantageous under pathological conditions, such as severe anemia chronic kidney disease, its beneficial effects on endurance in healthy remains questionable. Further studies are warranted in the field effects of rHuEPO that are independent of increasing hemoglobin such as peripheral vasodilation and tissue metabolic changes