Disorders in Magnesium Balance Decrease Erythrocyte Deformability in Athletes

Blood rheology was compared with the magnesium status in athletes (N = 45), who were divided into tertiles with a decreased ≤ 0.86 mmol/l), moderate (0.86–0.97 mmol/l), or high ≥0.97 mmol/l) Mg content in the blood serum. One-way ANOVA revealed differences in the erythrocyte suspension viscosity, total globulins, triglycerides, high density lipoprotein cholesterol (HDL Ch), plasma viscosity, and acid resistance of erythrocytes. According to discriminant analysis, key differences were associated with the erythrocyte deformability (ED), which was decreased in the lower and upper tertiles. The decrease in ED directly correlated with Mg content in the lower tertile and with HDL Ch in the upper tertile. The athletes with the increased Mg had increased plasma viscosity, which was due to elevated globulins and triglycerides. Thus, Mg imbalance in the athletes was associated with a decrease in ED.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 3, 2005, pp. 133–136.Original Russian Text Copyright © 2005 by Melnikov, Vikulov.     

Age-Related Erythrocyte Structure and Rheological Blood Properties in Athletes

The relationship between the rheological blood properties and several indices of age-related erythrocyte structure was established in endurance-training athletes (n = 21). Unlike nonathletic subjects, the athletes had a shift in the age-related structure towards younger erythrocyte forms: reticulocytosis, increased erythrocyte resistance, increased percentage of cells with a diameter exceeding 8 m, and decreased percentage of cells with a diameter of less than 7 m. The established correlations between total reticulocyte concentration, mature and immature reticulocyte concentrations, and percentage of cells with a diameter either exceeding 8 m or less than 7 m, on the one hand, and hemorheological parameters (blood viscosity, erythrocyte suspension viscosity, erythrocyte aggregation, and surface/volume ratio) and physical work capacity, on the other hand, revealed a significant effect of younger erythrocyte forms on hemorheological indices in athletes.     

Extra- and Intracellular Mechanisms of Changes in Erythrocyte Aggregation

Reversible aggregation is a form of erythrocyte behavior. The presence of α- and β-adrenergic receptors on erythrocyte membranes suggests that aggregation can be influenced by agonists of these receptors. Human erythrocyte aggregation (EA) was studied in the presence of α- and β-agonists of adrenergic receptors (in the concentration range from 10⁻⁶ to 10⁻⁸ M). The α₂-agonist clonidine stimulated EA most strongly (by 163%, P < 0.01). The cell reaction decreased from the α-agonist clonidine to the β-agonist metaproterenol. The phosphodiesterase inhibitor papaverine and the penetrating cAMP analogue dibutyryl cAMP (dB-cAMP) increased the intracellular cAMP and decreased EA by 46–50% (P < 0.05). Clonidine-induced stimulation of EA sharply decreased upon erythrocyte incubation in the presence of clonidine + dB-cAMP and became even lower than in the control. Thus, α-agonists of adrenergic receptors markedly stimulated EA. The adenylate cyclase-cAMP system is likely involved as an intracellular signaling pathway.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 4, 2005, pp. 108–112.Original Russian Text Copyright © 2005 by A. V. Murav’ev, A. A. Murav’ev.     

Protein Adsorption on Erythrocytic Membranes and Its Effect on Erythrocyte Rheology in Athletes during Competition Exercise

The adsorption of high-molecular-weight plasma proteins on erythrocyte membranes was studied in athletes after prolonged exercise under competition conditions. The adsorption of individual high-molecular-weight protein fractions depended on their concentration. The adsorption index changed biphasically at submaximum exercise. The adsorption of plasma high-molecular-weight protein fractions was associated with the fluidity of concentrated erythrocyte suspensions. The adsorbed high-molecular-weight globulins and fibrinogen had different effects on the parameters of erythrocyte rheology.     

Erythrocyte glutathione in goats

Fourteen Spanish goat breeds were studied, in order to ascertain the concentration of glutathione in erythrocytes. The mean value for all the animals (1365) was 81.14± 0.54 mg/100 ml and they were included in a unique group, GSH-high type.     

Aggregation pheromones in Collembola

The existence of aggregation pheromones is demonstrated in the Collembola Orchesella cincta, Orchesella villosa, and Tomocerus minor. Places conditioned by these animals can be considered as pheromone-sources, causing aggregation. Although for Tomocerus minor perception is not strictly species specific, all species investigated appear to be more responsive to their own pheromone than to those produced by other species. Both males and females appear to produce and perceive the aggregation pheromone. The distant action of the pheromone points to an olfactorially acting pheromone, in the perception of which the antennae play an important rôle. The behavioural reaction of the perceiving animals is orthokinetic.     

Aggregation in Dictyostelium discoideum

Cultured peritoneal macrophages have previously been shown to release a potent mitogen for mesenchymal cells. Peritoneal macrophages are derived from peripheral blood monocytes, one of the principal inflammatory cells associated with numerous tissue responses to injury. Cultured human monocytes can be activated by endotoxin or concanavalin A to secrete a potent growth factor(s) that is active on human smooth muscle cells, human fibroblasts and 3T3 cells. The optimal conditions for activation of monocyte release of this monocyte-derived growth factor(s) (MDGF) were to expose 5-day-old monocyte cultures (initially plated at 6.8 × 10⁵ cells/ml medium) to 10 μg/ml endotoxin or 6 μg/ml concanavalin A for approximately 20 hr. Monocytes can secrete MDGF into serum-free medium supplemented with 0.15% bovine serum albumin. MDGF stimulates both DNA synthesis and increase in cell number and is trypsin-sensitive, heat labile and nondialyzable. The relationship of MDGF to other monocyte products and its potential importance in wound repair and atherogenesis are discussed.