Stability Of Erythrocytes Research Articles

A new utilization area for hyperbaric oxygen? Improving quality of stored blood.

Since blood bags have the ability for diffusion of gases, we investigated whether hyperbaric oxygen (HBO) exposure affects several vital parameters of stored blood. Bloods obtained from the same persons were used as both control and HBO groups and stored in pediatric bags with citrate-phosphate-dextrose solution. HBO administration was performed at 2.5 atm for 90 min, started 1 day after blood collection and repeated every 2 days for a total of 10 times. The study was terminated on the 21st day. Complete blood count, glucose, pH, and osmotic fragility values were measured every week. Glucose and pH levels decreased in stored blood. In the HBO-exposed group, these decreases were less than in the control. In addition, mean corpuscular and platelet volumes tended to increase during storing process, but with HBO, these indexes remained lower, near physiologic levels. Another interesting finding of the study was the relative stable osmotic fragility ratio in the HBO group compared to the control blood. HBO exposure has positive effects on pH, stability of erythrocytes, and energy source (glucose) of the medium. Thus, we concluded that HBO may be a useful application for life and quality of stored blood.

Cerium Oxide Nanoparticles Restore Erythrocyte Stability to Acid Hemolysis in Old Rats

Cerium Oxide Nanoparticles Restore Erythrocyte Stability to Acid Hemolysis in Old Rats

Influence of acute exercise on the osmotic stability of the human erythrocyte membrane.

This study evaluated the effects of 2 different types of acute aerobic exercise on the osmotic stability of human erythrocyte membrane and on different hematological and biochemical variables that are associated with this membrane property. The study population consisted of 20 healthy and active men. Participants performed single sessions of 2 types of exercise. The first session consisted of 60 min of moderate-intensity continuous exercise (MICE). The second session, executed a week later, consisted of high-intensity interval exercise (HIIE) until exhaustion. The osmotic stability of the erythrocyte membrane was represented by the inverse of the salt concentration (1/H50) at the midpoint of the sigmoidal curve of dependence between the absorbance of hemoglobin and the NaCl concentration. The values of 1/H50 changed from 2.29±0.1 to 2.33±0.09 after MICE and from 2.30±0.08 to 2.23±0.12 after HIIE. During MICE mean corpuscular volume increased, probably due to in vivo lysis of older erythrocytes, with preservation of cells that were larger and more resistant to in vitro lysis. The study showed that a single bout of acute exercise affected erythrocyte stability, which increased after MICE and decreased after HIIE.

Influence of extracellular media's ionic strength on the osmotic stability of Sahel goat erythrocytes.

Heparinised blood was exposed to osmotic lysis in hypotonic buffered saline to evaluate erythrocyte membrane stability. When K3 EDTA blood was used, it added more to the ionic content of blood than heparin. The influence of suspending media's ionic strength on the osmotic stability of Sahel goat erythrocytes was investigated by replacing the ionic saline with non-ionic saccharide (sucrose or glucose) and assessing the effect of using EDTA blood instead of heparinised blood. The erythrocyte osmotic fragility curve in saline was hyperbolic even when the ionic concentration was reduced by 50% with saccharides. Haemolysis was higher with EDTA than heparinised blood at saline concentrations of 90 and 150-180 mosmol/L. The fragility curve was sigmoidal and shifted to the left when saline was completely substituted with a saccharide. The non-ionic saccharides increased erythrocyte osmotic resistance linearly (r=0.88; p<0.02) from median to minimal hyposmolarities (150-300 mosmol/L) and reduced the osmolyte concentration at median fragility by 36%. No effect occurred at <30-120 mosmol/L and >90% fragility; and saccharide concentrations were almost non-lytic at comparable saline concentrations evoking <10% haemolysis. Fragilities were neither affected by period (30-60 min) of incubation nor the type of saccharide used. In this study, the variation in osmotic stability of caprine erythrocytes was linked to ionic strength of the suspending extracellular media which seemed to exert an influence through transmembrane ion fluxes and regulatory volume changes in erythrocytes.

The osmotic resistance, and zeta potential responses of human erythrocytes to transmembrane modification of Ca2+ fluxes in the presence of the imposed low rate radiation field of 90Sr

Purpose: To investigate the effects of the imposed low dose rate ionizing field on membrane stability of human erythrocytes under modulation of transmembrane exchange of Ca2+.Materials and methods: Osmotic resistance of human erythrocytes was determined by a measure of haemoglobin released from erythrocytes when placed in a medium containing serial dilutions of Krebs isotonic buffer. The zeta potential as indicator of surface membrane potential was calculated from value of the cellular electrophoretic mobility. The irradiation of erythrocyte suspensions carried out by applying suitable aliquots of 90Sr in incubation media.Results: Irradiation of human erythrocytes by 90Sr (1.5–15.0 μGy·h−1) induced a reversible increase of hyposmotic hemolysis and negative charge value on the outer membrane surface as well as changed responses these parameters to modification of Ca2+ fluxes with calcimycin and nitrendipine.Conclusions: Findings indicate that the low dose rate radionuclides (90Sr) field modifies both Ca2+-mediated, and Ca2+-independent cellular signalling regulating mechanical stability of erythrocyte membrane. A direction of that modification presumably depends on the initial structure of membranes, and it is determined by the quality and quantitative parameters of changes in membrane structure caused by concrete operable factors.

The effect of near-infrared MLS laser radiation on cell membrane structure and radical generation

The therapeutic effects of low-power laser radiation of different wavelengths and light doses are well known, but the biochemical mechanism of the interaction of laser light with living cells is not fully understood. We have investigated the effect of MLS (Multiwave Locked System) laser near-infrared irradiation on cell membrane structure, functional properties, and free radical generation using human red blood cells and breast cancer MCF-4 cells. The cells were irradiated with low-intensity MLS near-infrared (simultaneously 808 nm, continuous emission and 905 nm, pulse emission, pulse-wave frequency, 1,000 or 2,000 Hz) laser light at light doses from 0 to 15 J (average power density 212.5 mW/cm(2), spot size was 3.18 cm(2)) at 22 °C, the activity membrane bound acetylcholinesterase, cell stability, anti-oxidative activity, and free radical generation were the parameters used in characterizing the structural and functional changes of the cell. Near-infrared low-intensity laser radiation changed the acetylcholinesterase activity of the red blood cell membrane in a dose-dependent manner: There was a considerable increase of maximal enzymatic rate and Michaelis constant due to changes in the membrane structure. Integral parameters such as erythrocyte stability, membrane lipid peroxidation, or methemoglobin levels remained unchanged. Anti-oxidative capacity of the red blood cells increased after MLS laser irradiation. This irradiation induced a time-dependent increase in free radical generation in MCF-4 cells. Low-intensity near-infrared MLS laser radiation induces free radical generation and changes enzymatic and anti-oxidative activities of cellular components. Free radical generation may be the mechanism of the biomodulative effect of laser radiation.

The effects of L-carnitine on some hematological parameters in rats fed a cholesterol-rich diet

We evaluated the effects of L-carnitine on the hematological characteristics of rats fed a cholesterol-rich diet. Healthy male Wistar Albino rats were assigned to four equal groups. During the 40 day experiment, group 1 was fed standard rat pellets, group 2 was fed standard rat pellets containing 7.5 % cholesterol powder, group 3 was fed standard rat pellets and water that contained 75 mg/l L-carnitine, and group 4 was fed standard rat pellets that contained 7.5% cholesterol and water that contained 75 mg/l L-carnitine. Blood samples were analyzed for red (RBC) and white (WBC) blood cells, hemoglobin, hematocrit, granulocytes, lymphocytes, monocytes, mean cell volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) using an automated cell counter. The RBC count in the group that received the 7.5% cholesterol diet was decreased significantly compared to the other groups. The hematocrit of the cholesterol group was lower than for the L-carnitine + cholesterol and L-carnitine groups. The MCV in the cholesterol group was significantly higher than the control group. The MCH in the cholesterol group was higher than for the other groups. There was no significant difference among the groups with regard to hemoglobin, MCHC, WBCs and leukocyte types. L-carnitine appears to have beneficial effects on erythrocyte stability, erythropoiesis and hyperlipidemia.

Spectrin and phospholipids — the current picture of their fascinating interplay

The spectrin-based membrane skeleton is crucial for the mechanical stability and resilience of erythrocytes. It mainly contributes to membrane integrity, protein organization and trafficking. Two transmembrane protein macro-complexes that are linked together by spectrin tetramers play a crucial role in attaching the membrane skeleton to the cell membrane, but they are not exclusive. Considerable experimental data have shown that direct interactions between spectrin and membrane lipids are important for cell membrane cohesion. Spectrin is a multidomain, multifunctional protein with several distinctive structural regions, including lipid-binding sites within CH tandem domains, a PH domain, and triple helical segments, which are excellent examples of ligand specificity hidden in a regular repetitive structure, as recently shown for the ankyrin-sensitive lipid-binding domain of beta spectrin. In this review, we summarize the state of knowledge about interactions between spectrin and membrane lipids.

Kinetics of hypotonic lysis of human erythrocytes

The curve of osmotic stability of erythrocytes is based on the amount of lysis as a function of salt concentration under fixed time incubation and represents an equilibrium situation after a sufficiently long time, although lysis is a rapid process. The curve is valid for the analysis of modulating agents that have influence on this equilibrium, but not for those that have influence on the lysis kinetics. This work has developed experimental conditions to study the hemolysis kinetics based on the interruption of lysis by hypertonicity at predetermined intervals of time. These conditions were used to evaluate the kinetics of hemolysis of 17 volunteers. The lysis curve as a function of time was statistically fitted to a hyperbola, using the analytical routine of the integrated kinetic model of Michaelis–Menten to determine the time required to promote lysis of half of the population of erythrocytes (t1/2) and the maximum absorbance (Amax) reached in the test. The results showed good variance among volunteers. The constant t1/2 was negatively correlated with total and LDL-cholesterol, and Amax, as it was expected, showed significant associations with hematological variables that are under the influence of hemoglobin levels. Stratification of the study population into two age groups (18–30 and 40–90 years old) showed that the t1/2 values were significantly lower in the older population. Although the study population has been small, the study showed that this kinetic approach of the erythrocyte lysis is very promising for analyzing the myriad of variables which have influence on the cell membrane.

Influence of Plasmodium vivax malaria on the relations between the osmotic stability of human erythrocyte membrane and hematological and biochemical variables

This study evaluated the influence of infection by Plasmodium vivax on the relations between hematological and biochemical variables and the osmotic stability of the erythrocyte membrane in a Brazilian Amazon population. A total of 72 patients with P. vivax malaria were included in the study and invited to return after 14 days, post-treatment with chloroquine and primaquine, for clinical and laboratorial reevaluations. The osmotic stability of the erythrocyte membrane was analyzed by nonlinear regression of the dependency of the absorbance of hemoglobin, released with hemolysis, as a function of the salt concentration, and it was represented by the inverse of the salt concentration at the midpoint of the curve (1/H 50) and by the variation of salt concentration, which promotes lysis (dX). Bivariate and multivariate methods were used in the analysis of the results. Prior to treatment of the disease, the erythrocytes showed greater stability, probably due to the natural selection of young and also more stable erythrocytes. The bivariate analysis showed that 1/H 50 was positively correlated with red cell distribution width (RDW), urea, triglycerides, and very low-density lipoprotein (VLDL)-cholesterol, but negatively associated with albumin, HDL-cholesterol, and indirect bilirubin, while dX was negatively associated with the mean corpuscular hemoglobin concentration. These associations were confirmed by canonical correlation analysis. Stepwise multiple linear regression showed that albumin, urea, triglycerides, and VLDL-cholesterol are the variables with the highest abilities of predicting erythrocyte stability. The bivariate analysis also showed that the hematological index RDW was related to elevated levels of bilirubin and decreased levels of albumin and urea, associated with liver damage resulting from malaria.

Influence of age on the correlations of hematological and biochemical variables with the stability of erythrocyte membrane in relation to sodium dodecyl sulfate

ObjectivesTo evaluate the influence of age on the relationships between biochemical and hematological variables and stability of erythrocyte membrane in relation to the sodium dodecyl sulfate (SDS) in population of 105 female volunteers between 20 and 90 years.MethodsThe stability of RBC membrane was determined by non-linear regression of the dependency of the absorbance of hemoglobin released as a function of SDS concentration, represented by the half-transition point of the curve (D50) and the variation in the concentration of the detergent to promote lysis (dD).ResultsThere was an age-dependent increase in the membrane stability in relation to SDS. Analyses by multiple linear regression showed that this stability increase is significantly related to the hematological variable red cell distribution width (RDW) and the biochemical variables blood albumin and cholesterol.DiscussionThe positive association between erythrocyte stability and RDW may reflect one possible mechanism involved in the clinical meaning of this hematological index.

Microscopic evaluation of vesicles shed by rat erythrocytes at elevated temperatures

It is hypothesized that the elevation of the temperature of the blood during heat stress may cause an increase of the shedding of erythrocyte membrane vesicles. Therefore, the increase of vesicle numbers following heat stress may be indicative of and proportional to the level heat stress. In order to test this hypothesis, erythrocytes and the vesicles shed by erythrocytes were collected from rat blood and analyzed after the elevation of body temperature by exposure to external heat. The images of erythrocytes and vesicles were analyzed by a custom light microscopy system with spatial resolution of better than 90nm. The samples were observed in an aqueous environment and required no freezing, dehydration, staining, shadowing, marking or any other manipulation. The elevation of temperature from 36.7±0.3 to 40.3±0.4°C resulted in significant increase of the concentration of vesicles in blood. At a temperature of 37°C, mean vesicle concentrations and diameters found in rat blood were (1.4±0.2)×106 vesicles/μL and 0.436±0.03μm, respectively. The concentration of free vesicles increased after exposure to heat to (3.8±0.3)×106 vesicles/μL. It was estimated that 80% of all vesicles found in rat blood are smaller than 0.45μm. The increase in the number of vesicle associated with elevated temperatures may be indicative of the heat stress level and serve as diagnostic test of erythrocyte stability and heat resistance.

Comparison of bicarbonate‐buffered fluid and isotonic saline solution as Cell Saver washing fluids for packed red blood cells

Massive transfusion (MT) can cause severe electrolyte and acid-base disturbances in neonates and infants due to the unphysiological composition of packed red blood cells (PRBCs). Washing of the PRBCs using Cell Saver systems prior to MT is recommended for this reason. The composition of normal saline (NaCl), the standard wash fluid for Cell Saver systems, is considerably different from that of physiological plasma. The aim of the study presented here was to investigate the effect of washing the PRBCs with a bicarbonate-buffered hemofiltration solution (BB-HS) in comparison with washing with NaCl and to evaluate the impact on electrolyte concentrations, acid-base balance and the stability of PRBCs. In an experimental in vitro setting, PRBCs were washed with Cell Saver systems prepared with NaCl or BB-HS as washing solutions. Before and after the washing procedure, electrolyte concentrations, acid-base parameters, adenosine triphosphate (ATP) and free hemoglobin (fHb) concentrations were measured. In both groups, the potassium concentrations decreased (baseline: 18.4 ± 5.17 mmol·l(-1), end of study: NaCl 2.71 ± 1,81 mmol·l(-1), BB-HS 2.50 ± 1.54 mmol·l(-1), P < 0.05) while the acid-base balance improved only in the BB-HS-group (baseline: base excess -21.6 ± 3.52 mmol·l(-1), end of study: NaCl -30.2 ± 1.42 mmol·l(-1), BB-HS -7.51 ± 2.49 mmol·l(-1) , P < 0.05). Furthermore, markers of erythrocyte stability such as fHb and ATP concentrations were improved in the BB-HS-group. Washing of PRBCs with BB-HS rather than NaCl results in a more physiological composition with improvements of electrolyte concentrations, acid-base balance and erythrocyte stability.

Slow Freezing Coupled Static Magnetic Field Exposure Enhances Cryopreservative Efficiency—A Study on Human Erythrocytes

The aim of this study was to assess the cryoprotective effect of static magnetic fields (SMFs) on human erythrocytes during the slow cooling procedure. Human erythrocytes suspended in 20% glycerol were slowly frozen with a 0.4-T or 0.8-T SMF and then moved to a −80°C freezer for 24 hr. The changes in survival rate, morphology, and metabolites of the thawed erythrocytes were examined. To understand possible cryoprotective mechanisms of SMF, membrane fluidity and dehydration stability of SMF-exposed erythrocytes were tested. For each test, sham-exposed erythrocytes were used as controls. Our results showed that freezing coupled with 0.4-T or 0.8-T SMFs significantly increased the relative survival ratios of the frozen-thawed erythrocytes by 10% and 20% (p<0.001), respectively. The SMFs had no effect on erythrocyte morphology and metabolite levels. However, membrane fluidity of the samples exposed to 0.8-T SMF decreased significantly (p<0.05) in the hydrophobic regions. For the dehydration stability experiments, the samples exposed to 0.8-T SMF exhibited significantly lower (p<0.05) hemolysis. These results demonstrate that a 0.8-T SMF decreases membrane fluidity and enhances erythrocyte membrane stability to resist dehydration damage caused by slow cooling procedures.

Bivariate and multivariate analyses of the correlations between stability of the erythrocyte membrane, serum lipids and hematological variables

The observation that the fluidity must remain within a critical interval, outside which the stability and functionality of the cell tends to decrease, shows that stability, fluidity and function are related and that the measure of erythrocyte stability allows inferences about the fluidity or functionality of these cells. This study determined the biochemical and hematological variables that are directly or indirectly related to erythrocyte stability in a population of 71 volunteers. Data were evaluated by bivariate and multivariate analysis. The erythrocyte stability showed a greater association with hematological variables than the biochemical variables. The RDW stands out for its strong correlation with the stability of erythrocyte membrane, without being heavily influenced by other factors. Regarding the biochemical variables, the erythrocyte stability was more sensitive to LDL-C. Erythrocyte stability was significantly associated with RDW and LDL-C. Thus, the level of LDL-C is a consistent link between stability and functionality, suggesting that a measure of stability could be more one indirect parameter for assessing the risk of degenerative processes associated with high levels of LDL-C.

Safety Aspects in Treatment of Cancer by Carbamate Insecticides as Measured by Osmotic Fragility of Erythrocytes

Cancer chemotherapy using carbamate insecticides has been published by the first author. This study was to evaluate their effects on other cell types because; pesticides and insecticides can affect the health of living organisms through different mechanisms such as membrane denaturation. The evaluation of the deleterious effects of chemical agents on biological membranes can be performed through the analysis of the stability of erythrocytes against a concentration gradient of certain chemical agent in physiologic saline solution. In the present study, technical grade carbamate insecticides viz., propoxur, carbaryl and carbofuran were tested for their toxicity on erythrocytes in vitro. Osmotic fragility of erythrocytes in different concentrations of saline, following exposure to technical grade carbamates was studied in order to indirectly assess the degree of anaemia and hypoxia, resulting upon exposure to carbamates. The percent hemolysis of sheep erythrocytes without carbamates (control), initiated at 0.45 percent NaCl solution, which reached 50% at 0.40 percent NaCl concentration. Complete hemolysis was seen at 0.35 percent NaCl.Baygon treated erythrocytes showed initial, 50% and complete hemolysis at 0.55, 0.45 and 0.35% NaCl respectively i.e. a little earlier as compared to the control. Carbaryl treated erythrocytes showed initial 50% and complete hemolysis at 0.65% NaCl, 0.55% and 0.45% concentration of NaCl respectively. Carbofuran exhibited less toxic effects on the fragility of erythrocytes as compared to baygon and carbaryl, where in the initial, 50% and complete haemolysis was seen at 0.50, 0.45 and 0.40 percent NaCl respectively. Though carbamate insecticides affected the integrity of the erythrocytes, the effect is transient and reversible and hence they can safely be used as chemotherapeutic agents for cancer.

Membrane stability and methaemoglobin content of human erythrocytes incubated in aqueous leaf extract of Nicotiana tabacum product

The present study seeks to ascertain membrane stability and methaemoglobin content (%MetHb) of human erythrocytes suspended in aqueous leaf extract of N. tabacum. Erythrocyte membrane stability (%EMS) and %MetHb were measured by spectrophotometric method. Erythrocytes incubated in the five experimental concentrations of N. tabacum exhibited higher tendency to haemolyze in phosphate buffered saline solution [PBS] &gt; 0.54 g/100 mL, whereas erythrocytes incubated in aqueous extracts of [N. tabaccum] = 0.4 and 0.8 mg/100 mL showed relatively lower level of haemolysis in [PBS] &lt; 0.54 g/100 mL, compared with the control samples. Experimental [N. tabacum] = 2.0 mg/100 mL caused destabilization of erythrocyte membrane by 13.3%. %MetHb of control and erythrocytes treated with aqueous extracts of N. tabacum ranged between 0.58 ± 0.09 and 1.89 ± 0.12%. Specifically, erythrocytes treated with [N. tabacum] = 0.4 mg/100 mL gave %MetHb = 0.59 ± 0.08; p &lt; 0.05. Experimental [N. tabacum] = 2.0 mg/100 mL engendered a paradoxical reduction in erythrocyte %MetHb = 0.58 ± 0.09; p &gt; 0.05. The medium negative correlation (r = −0.62421) between MCF and %MetHb was an indication that N. tabacum destabilizing effect, exemplified by [N. tabacum] = 0.2 mg/100 mL; %MetHb = 0.58 ± 0.09; %EMS = −13.3, was not an oxidative process, but by mechanical perturbation by constituents of the plant extract on erythrocyte membrane structural components. Erythrocyte %MetHb in the presence of the five experimental [N. tabacum] = 0.4 − 2.0 mg/100 mL did not cause toxic methaemoglobinemia in vitro.

Effects of low doses of gamma rays on the stability of normal and diabetic erythrocytes.

We studied the influence of low doses of γ radiation (from 0.04 to 1.8 mGy) on the stability of human red blood cells (RBC) from healthy donors and diabetic patients using absorption spectroscopy. Because of the alteration of many enzymatic pathways in diabetic RBCs resulting in strong modification of the lipid and protein membrane components one could expect that the ionizing γ-radiation should influence the stability of the healthy and diabetic cells in a different way. Indeed, distinct discontinuities and monotonic changes of hemolysis detected in the healthy and diabetic RBCs suggest that various enzymatic and chemical processes are activated in these membranes by γ radiation. Mössbauer measurements showed that only the highest applied dose of γ radiation caused modification of hemoglobin in both types of RBCs.

Effects of Roundup® Pesticide on the Stability of Human Erythrocyte Membranes and Micronuclei Frequency in Bone Marrow Cells of Swiss Mice

Pesticides can affect the health of living organisms through different mechanisms such as membrane denaturation. The evaluation of the deleterious effects of chemical agents on biological membranes can be performed through the analysis of the stability of erythrocytes against a concentration gradient of certain chemical agent in physiologic saline solution. This work analyzed the effect of the herbicide Roundup ® on the membrane of human erythrocytes in blood samples collected with EDTA or heparin as anticoagulant agent. The results were analyzed through spectrophotometry at 540 nm and light microscopy. There was an agreement between spectrophometric and morphologic analyses. At the concentration limit recommended for agricultural purposes, Roundup ® promoted 100% of hemolysis. The D50Roundup ® values obtained for human blood samples collected with EDTA were not significantly different from those obtained for samples collected with heparin. However, the lysis curves presented lower absorbance values at 540 nm in the presence of blood collected with EDTA in relation to that collected with heparin, probably due to hemoglobin precipitation with EDTA. This work also analyzed the effects of three different Roundup ® doses (0.148, 0.754 and 1.28 mg/kg) on the micronuclei frequency in bone marrow cells of Swiss mice in relation to a positive control of cyclophosphamide (250 mg/kg). The two highest Roundup ® doses showed the same genotoxicity level as the positive control.

Influence of Glucose Concentration on the Membrane Stability of Human Erythrocytes

The action of glucose as an osmolyte in relation to blood cells is not well-characterized in the literature. This study aimed to study the influence of glucose concentration on the stability of red blood cells. The stability of erythrocytes was evaluated by the half-transition point obtained from the curves of lysis induced by glucose in the absence of salt or by increase in medium hypotonicity in the absence and the presence of different concentrations of glucose. In the presence of 0.9 g/dl NaCl, there was no hemolysis with increasing concentration of glucose from 0 to 10 g/dl. In the absence of NaCl, the dependence of hemolysis with the 0-10 g/dl glucose was described by a decreasing sigmoid, with fully lysed and fully protected cells being encountered in the presence of 0-2 and 4-10 g/dl glucose, respectively. The possible origin of such stabilization effect is discussed with base of what is known about osmostabilization of biological complexes and about the influence of glucose on the rheological properties of erythrocytes.