Glutaraldehyde effect on the osmotic fragility and rate of haemolysis of human erythrocytes: a kinetic study

The effect of glutaraldehyde treatment on the osmotic fragility and rate of haemolysis of human erythrocytes was studied in the temperature domain 22-42 degrees C at different aldehyde concentrations from 0.010 to 0.040% (w/v). The osmotic fragility linearly decreases at increasing temperatures for all glutaraldehyde concentrations with approximately the same slope as for the untreated erythrocytes. Rather similar effects are produced on the rate of haemolysis. It was not possible to define unique activation energies. The maximal haemolysis becomes smaller after the treatment with increasing concentrations of glutaraldehyde but more erythrocytes are no longer able to tolerate normally non-haemolysing osmotic stretching, this suggesting an artificial "ageing" of erythrocytes. The formation of a membrane protein skeleton as a result of cross-linking is inferred, while the changes in the cytoskeletal spectrin network seem to be less important.     

The relationship between the osmotic fragility of human erythrocytes and cell age

Erythrocytes in a normal blood sample are hemolyzed over a range of hypotonic salt concentrations. In order to investigate the relationship between the distribution of osmotic fragilities and the distribution of cellular ages, the osmotic fragility has been compared with three indices of cellular age. The activity of glutamic-oxalacetic transaminase (GOT) and the percentage hemoglobin A_1C were measured in samples hemolyzed in different hypotonic salt concentrations. The osmotic fragility curve was also obtained for cells of different density separated by centrifugation. These experiments indicate that the fragility distribution is not an accurate reflection of the distribution of cellular ages. The mean fragility for older cells is higher than that of younger cells. However, cellular aging does not produce a gradual increase in osmotic fragility. Instead, it seems to produce changes which can both increase and decrease the fragility, resulting in a broader distribution of fragilities with some of the older cells actually less fragile than the younger ones.     

The effect of n-3 fatty acids on osmotic fragility of rat erythrocytes

In order to study the effect of n-3 fatty acids on the physical state of the erythrocyte membrane, measured as osmotic fragility, rats were fed a diet supplemented in n-3 fatty acids (1.5 ml/day, 35% 20:5, 30% 22:6) for 21 days. With salt concentrations ranging from 0.37% to 0.44%, osmotic resistance was increased by 25% to 45% in cells from n-3-fed animals compared to controls. No change was observed in either phospholipid or cholesterol content in the membrane. A small, but still significant difference (P less than 0.05) in phospholipid sub-class distribution was observed in that the phosphatidylethanolamine fraction was decreased and the phosphatidylserine fraction increased after n-3 supplementation. The major change was, however, that the level of eicosapentaenoic acid (20:5(n-3] in phospholipids was increased from 1.5% of total fatty acids to 4.5%. This increase was mainly at the expense of linoleic acid (18:2(n-6]. No change was observed in the level of docosahexaenoic acid (22:6(n-3]. It is thus concluded that both the fatty acid composition and the nature of the phospholipid polar head group may influence the osmotic fragility of erythrocytes.     

Curves of osmotic fragility calculated from the isotonic areas and volumes of individual human erythrocytes

Theoretical osmotic fragility curves were calculated and drawn by computer using the van't Hoff equation and the isotonic areas and volumes of 1000 individual erythrocytes. We studied the influence on the calculated curves of theoretically altering the fraction of the volume which was osmotically active from 50 to 70%, and of altering the permissible stretch before hemolysis from zero to 10%. With the two assumptions–that the membrane does not stretch before hemolysis, and that the osmotically active fraction of the cell volume is 0.58–it was possible to duplicate the general shape of the standard fragility curve; the exact NaCl concentration, however, at which there was 50% hemolysis was approximately 0.1 gm/100 ml higher than found in vitro. The calculated osmotic fragility curves can be made quantitatively similar to in vitro ones if the following statements are true: the osmotically active volume is 58%, the permissible stretch of the membrane without lysis is 6%, the cell membrane resists a slight osmotic pressure gradient of approximately 0.1 atmospheres, and hemolysis is an all or nothing phenomenon. This set of values for the relevant factors is sufficient but not unique in causing the superposition of the calculated and experimental curves. The frequency distribution of the cells according to the hemolytic salt concentrations (the sodium chloride concentration at which an individual cell just hemolyzes) was skewed positively and was leptokurtic for each of the seven normal subjects studied.     

The approximate entropy of the electromyographic signals of tremor correlates with the osmotic fragility of human erythrocytes

Background  

The main problem of tremor is the damage caused to the quality of the life of patients, especially those at more advanced ages. There is not a consensus yet about the origins of this disorder, but it can be examined in the correlations between the biological signs of aging and the tremor characteristics.     

A computerized method for the determination of the osmotic fragility curve of erythrocytes

A computerized and precise method for the determination of the osmotic fragility curve of erythrocytes was developed. The pH and the temperature, the most important factors for the osmotic hemolysis, were controlled with an accuracy of 7.40 ± 0.01 and 25.0 ± 0.2°C, respectively. The method required an extremely minute amount of blood (about 5 μl). The fragility curve represented by the cumulative and first derivative curves as a function of salt concentration had excellent reproducibility for the mean corpuscular fragility and the slope of the fragility curve. The method was applied to erythrocytes treated with glutaraldehyde and to those with the various contents of cholesterol in the membrane.     

Increase in osmotic fragility of bovine erythrocytes induced by bacterial phospholipases C

Bovine erythrocytes were treated with each of three bacterial phospholipases C; phosphatidylcholine-hydrolyzing phospholipase C (PCase) of Clostridium perfringens, sphingomyelinase C (SMase) of Bacillus cereus and phosphatidylinositol-specific phospholipase C (PIase) of Bacillus thuringiensis. An increase in osmotic fragility was detected by means of a coil planet centrifugation (CPC) apparatus (Biomedical Systems Co., Tokyo) after the treatment with these enzymes. The peak of hemolysis normally observed in the untreated erythrocytes at the range between 50 and 100 mOsM shifted to 160 to 200 mOsM with the progress of sphingomyelin hydrolysis by phospholipase C of C. perfringens. Sphingomyelinase C of B. cereus showed two different effects on bovine erythrocytes: In the absence of divalent cations or in the presence of Ca2+ alone, the peak of hemolysis shifted to the region from 130 to 160 mOsM, without appreciable hydrolysis of sphingomyelin, while in the presence of Mg2+ or Mg2+ plus Ca2+, the peak of hemolysis further shifted to the region from 160 to 200 mOsM with the hydrolysis of sphingomyelin. Abrupt shift in osmotic fragility to a much higher region around 250 mOsM was produced by treatment with increasing amounts of phosphatidylinositol-specific phospholipase C. In this case, a significant amount of acetylcholinesterase was released from the erythrocyte membrane without hot or hot-cold hemolysis. The mechanism of alteration of osmotic fragility of bovine erythrocytes by treatment with phospholipases C seems to differ from case to case, depending upon the specific action of each enzyme toward the membrane phospholipids.     

The effect of the saturation and isomerization of dietary fatty acids on the osmotic fragility and water diffusional permeability of rat erythrocytes

Weanling rats were fed semi-purified diets containing 15% by weight of either corn oil, a high oleic acid safflower oil, lard or hydrogenated soybean oil. Significant changes in the fatty acid composition of erythrocytes were induced by these dietary fats. The compositional changes did not effect water diffusional permeability, but did affect their osmotic fragility. An increased fragility appeared to be associated with an increased octadecenoate content of the membranes.     

The erythrocyte membrane site for the effect of temperature on osmotic fragility

The osmotic fragility of human erythrocytes is well known to decrease as the temperature is elevated. The cellular site for the temperature effect was studied by assessing possibles roles of hemoglobin and of membrane lipids and by taking advantage of the unique response of camel erythrocytes to temperature. It is concluded that the erythrocyte membrane is the site for the temperature effect on osmotic fragility. The human erythrocyte is likely to rupture in protein-lipid boundary regions in the membrane, from which cholesterol is apparently excluded.     

The changes of osmotic fragility of pig erythrocytes induced by organophosphorus insecticides.

Organophosphorus insecticides: methylbromphenvinphos, dichlorvos, malathion and methylparathion exert antilytic effects on pig erythrocytes by preventing osmotic disruption of membranes in hypotonic saline media. The order of effectiveness is the following: methylbromphenvinphos, methylparathion, malathion, dichlorvos.     

Erythrocyte membrane in protein-energy malnutrition: A23187-induced changes in osmotic fragility of human and rat erythrocytes

Erythrocytes from protein-energy malnourished children have been shown to have increased resistance to osmotic lysis (4). Osmotic fragility studies were carried out in protein-energy malnourished rats and A23187-induced changes in osmotic fragility were studied in rat and human erythrocytes. Rat erythrocytes were found to be much more sensitive to A23187 effect on osmotic fragility as compared to the human erythrocytes. Erythrocytes from protein-deficient rats but not from the energy-restricted rats showed increased resistance to osmotic lysis. A23187 (+Ca)-induced changes in osmotic fragility were not different between control and experimental erythrocytes, either for humans or rats. There was, however, a difference in the extent to which Na accumulation and K depletion occurred in erythrocytes from control and experimental animals after A23187 + Ca²⁺ treatment.     

Protective effect rendered by human ceruloplasmin on erythrocytes in hepatocerebral dystrophy

In order to elucidate the protective effect of human ceruloplasmin (CP) on erythrocytes in patients with hepatocerebral dystrophy (HCD), the parameters reflecting the interaction of CP from the blood of healthy donors (n-CP) and of HCD patients (h-CP) with erythrocytes from healthy donors (n-ER) and from HCD patients (h-ER) were estimated. The protective effects of n-CP and h-CP on n-ER and h-ER during the Cu2+-induced lysis were compared. It was shown that the ability of h-CP to prevent the human ER breakdown upon Cu2+-induced lysis is much lower (approximately 3-fold) than that of n-CP. The differences in the protective effect of n-CP and h-CP are manifested in a greater degree during the n-ER lysis than during the h-ER lysis.