—Aggregation of intact and ATP-depleted human erythrocytes, which was induced by FeCl3at a final concentration of 200 μM, was studied. The shape of erythrocytes and the stability of their...

The process of erythrocyte aggregation in autologous plasma and 3% dextran 70 solution was studied by light microscopy (1000x). When a suspension of washed erythrocytes is placed between two glass surfaces, they lose their biconcave discoidal shape and turn into echinocytes. After adding autologous plasma to echinocytes and intensive agitation, they are converted into discocytes, and then into stomatocytes. After that, the stomatocytes were combined into aggregates in the form of rouleaux. The addition of saline solution to the aggregates of red blood cells in autologous plasma led to cell disaggregation. At the same time, the appearance of stomatocytes from aggregates was observed. The addition of dextran 70 solution to echinocytes did not lead to their aggregation. At the same time, the addition of albumin to echinocytes restored the discoidal shape of the cells and turned them into stomatocytes. It was found that after adding dextran 70 solution to the stomatocytes, their strong aggregation occured. Treatment of echinocytes with trypsin did not restore the shape of red blood cells, but caused strong aggregation of echinocytes induced by dextran 70. A possible mechanism of erythrocyte aggregation is discussed.

Introduction. One of the main factors involved in the pathogenesis of burn disease consists in the disturbance of microcirculation and haemostasis, caused by increased platelet aggregation. Mechanisms underlying the enhancement of platelet aggregation are poorly understood. Main results were obtained for adult patients at the onset of the burn disease, with no similar data on paediatric patients being available. There is evidence of a relationship between the size of platelets (MPV) and their functionality.Aim. To undertake a study of spontaneous and ADP-induced platelet aggregation and their size in children with burn disease.Materials and methods. We studied the aggregation and size of platelets in children aged 3–17 years, in whom burn areas covered 10–70 % of the body surface at the onset of the disease and before discharge. Spontaneous platelet aggregation was analysed under conditions of induced shear flow, whereas ADP-induced aggregation was studied employing a turbidimetric method. The study of platelet sizes was carried out using a conductometric method.Results. Spontaneous platelet aggregation increases significantly in children with burn disease. The integrated optical density of the formed aggregates, their area and perimeter were estimated for the first time. These indicators remained elevated even after burn wounds had been completely closed. In burn disease, changes in ADP-induced platelet aggregation were multidirectional in nature. Mean platelet volume (MPV) was increased during the acute period of burn disease, decreased during the period of toxaemia, and normalised by the time of patients’ discharge. Changes in MPV did not affect the aggregation properties of platelets. There was no correlation between the degree of aggregation and the severity of hyperfibrinogenemia. The blood of burn patients contained a large number of activated platelets, which was the reason for the increase in their spontaneous aggregation, not requiring the participation of exogenous inducers.Conclusion. An increase in spontaneous platelet aggregation was observed in children after a thermal injury, which remained elevated until the burn wounds were completely closed. A significant increase in the number of activated platelets constituted the reason for the increase in spontaneous platelet aggregation.Conflict of interest: the authors declare no confl ict of interest.Financial disclosure: the study had no sponsorship.

We studied the influence of metabolic depletion of RBCs on their shape, stability cytoskeleton, anionic sites, deformation, aggregate morphology and aggregation. The blood was stored in the presence of an anticoagulant (sodium citrate) at 4 ° C during 14 days. It has been shown that during the storage of blood in RBCs the ATP level decreases, a large number of echinocytes and spheroechinocytes appear, the stability of their cytoskeleton and the content of anionic sites decreases. The deformation of RBCs in the artificial shear flow and of their aggregation in the autologous plasma decreases. At the same time, the pH and sodium level in the blood plasma decreases, and the potassium level increases. The plasma content of free hemoglobin increases. With the help of light microscopy, it was found that echinocytes of stored blood begin to aggregate with each other. The possible mechanisms RBC aggregation in the form of rouleaux and echinocytes are discussed.

A new method for measuring the quantitative indicator of the degree of red blood cell (RBC) aggregation in autologous blood plasma by automated analysis of images obtained using a light microscope is described. A method for measuring the degree of RBC aggregation in autologous blood plasma includes preprocessing, image acquisition and automated image analysis, image binarization, defining the boundaries of objects found, classifying objects into two classes (single RBC and aggregates) and calculating a numerical indicator reflecting the degree of RBC aggregation. The result of the treatment is an indicator of the degree of RBC aggregation in autologous blood plasma. The proposed method makes it possible to assess of RBC aggregation in autologous blood plasma and thereby obtain additional diagnostic and scientific information, increase the accuracy of assessing the degree of RBC aggregation in autologous blood plasma.

The process of erythrocyte aggregation in autologous plasma and 3% dextran 70 solution was studied by light microscopy (1000x). When a suspension of washed erythrocytes is placed between two glass surfaces, they lose their biconcave discoidal shape and turn into echinocytes. After adding autologous plasma to echinocytes and intensive agitation, they are converted into discocytes, and then into stomatocytes. After that, the stomatocytes were combined into aggregates in the form of rouleaux. The addition of saline solution to the aggregates of red blood cells in autologous plasma led to cell disaggregation. At the same time, the appearance of stomatocytes from aggregates was observed. The addition of dextran 70 solution to echinocytes did not lead to their aggregation. At the same time, the addition of albumin to echinocytes restored the discoidal shape of the cells and turned them into stomatocytes. It was found that after adding dextran 70 solution to the stomatocytes, their strong aggregation occured. Treatment of echinocytes with trypsin did not restore the shape of red blood cells, but caused strong aggregation of echinocytes induced by dextran 70. A possible mechanism of erythrocyte aggregation is discussed.