The stability of human erythrocytes to sodium dodecyl sulfate (SDS) was assessed spectrophotometr... more The stability of human erythrocytes to sodium dodecyl sulfate (SDS) was assessed spectrophotometrically in the presence of different concentrations of bovine serum albumin (BSA) and at different temperatures (27–45 °C). The absorbance at 540 nm (A 540 ) was correlated with the SDS concentration by sigmoidal regression based on the Boltzmann equation. Erythrocyte stability was characterized on the basis of the SDS concentration that induces hemolysis in 50% of the cells (D 50 ). Progressive increases in the albumin concentration led to increases in the D 50 value. The protective effect of BSA against SDS-induced hemolysis was attributed to the binding of the surfactant to the hydrophobic binding sites of this protein. The D 50 values decreased sigmoidally with an increase in the temperature. This trend, which could not be explained by changes in the spectral properties of hemoglobin, maybe due to heterogeneity in the erythrocyte population.
This work evaluated the dependence of erythrocyte membrane stability on age, temperature (26, 32,... more This work evaluated the dependence of erythrocyte membrane stability on age, temperature (26, 32, 37, 42 and 47 degrees C), nutritional status, red cell count, red cell distribution width (RDW) and mean corpuscular volume (MCV) in human females (n = 67, 20-94 years). Erythrocyte membrane resistance to hypotonic lysis was expressed as the NaCl concentration (H(50)) capable of promoting 50% haemolysis. A nutritional evaluation was performed using the Mini Nutritional Assessment (MNA) instrument, which showed that 76.1% of the study group were well nourished and 23.9% were at risk of malnutrition. H(50) demonstrated a negative correlation with age at all temperatures. H(50) showed no correlation with either MNA scores or with any haematological indices. The power and significance of the correlations improved when we censored from the analyses those individuals at risk of malnutrition. The thermal dependencies lines for H(50) demonstrated higher values for females 20-39 years of age compared with those more than 60 years of age. These results suggest that erythrocyte resistance to hypotonicity (erythrocyte membrane stability), increased with age of study volunteers. This increased stability was more pronounced among well-nourished individuals.
The stability of human erythrocytes to sodium dodecyl sulfate (SDS) was assessed spectrophotometr... more The stability of human erythrocytes to sodium dodecyl sulfate (SDS) was assessed spectrophotometrically in the presence of different concentrations of bovine serum albumin (BSA) and at different temperatures (27–45 °C). The absorbance at 540 nm (A 540 ) was correlated with the SDS concentration by sigmoidal regression based on the Boltzmann equation. Erythrocyte stability was characterized on the basis of the SDS concentration that induces hemolysis in 50% of the cells (D 50 ). Progressive increases in the albumin concentration led to increases in the D 50 value. The protective effect of BSA against SDS-induced hemolysis was attributed to the binding of the surfactant to the hydrophobic binding sites of this protein. The D 50 values decreased sigmoidally with an increase in the temperature. This trend, which could not be explained by changes in the spectral properties of hemoglobin, maybe due to heterogeneity in the erythrocyte population.
This work evaluated the dependence of erythrocyte membrane stability on age, temperature (26, 32,... more This work evaluated the dependence of erythrocyte membrane stability on age, temperature (26, 32, 37, 42 and 47 degrees C), nutritional status, red cell count, red cell distribution width (RDW) and mean corpuscular volume (MCV) in human females (n = 67, 20-94 years). Erythrocyte membrane resistance to hypotonic lysis was expressed as the NaCl concentration (H(50)) capable of promoting 50% haemolysis. A nutritional evaluation was performed using the Mini Nutritional Assessment (MNA) instrument, which showed that 76.1% of the study group were well nourished and 23.9% were at risk of malnutrition. H(50) demonstrated a negative correlation with age at all temperatures. H(50) showed no correlation with either MNA scores or with any haematological indices. The power and significance of the correlations improved when we censored from the analyses those individuals at risk of malnutrition. The thermal dependencies lines for H(50) demonstrated higher values for females 20-39 years of age compared with those more than 60 years of age. These results suggest that erythrocyte resistance to hypotonicity (erythrocyte membrane stability), increased with age of study volunteers. This increased stability was more pronounced among well-nourished individuals.
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