Lead-induced changes of cation-osmotic hemolysis in rats.

Erythrocyte microrheology changes were measured using cation-osmotic hemolysis (COH) in healthy rats and rats after 6 and 12 months of lead ingestion. Using COH, properties of two membrane constituents, spectrine membrane skeleton and membrane bilayer were studied. COH in rats after 12 months of lead ingestion was significantly lower only in the area with lower ionic strength (15.4-61.6 mmol x l(-1) of NaCl) (p < 0.01 resp. p < 0.05). No changes in COH were found after 6 months of continuous lead ingestion. The relation between cation-osmotic hemolysis and erythrocyte deformability is being discussed.     

Differences between cation-osmotic hemolysis and filterability in exaprolol- and glutaraldehyde-treated human red blood cells

The changes in human red blood cell microrheology in different glutaraldehyde (3.0 and 5.0 x 10(-6) mol x l(-1)) and exaprolol (2.5 and 5.0 x 10(-4) mol x l(-1)) concentrations were studied. The method of millipore filtration was compared with the method of cation-osmotic hemolysis. Both drugs prolonged the filtration time. Cation-osmotic hemolysis in glutaraldehyde-treated cells was significantly lower in comparison with the control group. On the other hand, there was a significant increase in cation-osmotic hemolysis in exaprolol-treated cells. Besides cation-osmotic hemolysis and filterability of erythrocytes, we evaluated the medium cell volume (MCV) and the medium cell hemoglobin concentration (MCHC). No changes in MCV and MCHC in glutaraldehyde-treated cells were observed. However, the MCV was significantly lower and the MCHC was significantly higher in exaprolol-treated cells. In conclusion, we suggest that the method of cation-osmotic hemolysis is more sensitive than the filtration method for determination of red blood cell microrheology.     

Studies on the role of goat heart galectin-1 as an erythrocyte membrane perturbing agent

Galectins are β-galactoside binding lectins with a potential hemolytic role on erythrocyte membrane integrity and permeability. In the present study, goat heart galectin-1 (GHG-1) was purified and investigated for its hemolytic actions on erythrocyte membrane. When exposed to various saccharides, lactose and sucrose provided maximum protection against hemolysis, while glucose and galactose provided lesser protection against hemolysis. GHG-1 agglutinated erythrocytes were found to be significantly hemolyzed in comparison with unagglutinated erythrocytes. A concentration dependent rise in the hemolysis of trypsinized rabbit erythrocytes was observed in the presence of GHG-1. Similarly, a temperature dependent gradual increase in percent hemolysis was observed in GHG-1 agglutinated erythrocytes as compared to negligible hemolysis in unagglutinated cells. The hemolysis of GHG-1 treated erythrocytes showed a sharp rise with the increasing pH up to 7.5 which became constant till pH 9.5. The extent of erythrocyte hemolysis increased with the increase in the incubation period, with maximum hemolysis after 5 h of incubation. The results of this study establish the ability of galectins as a potential hemolytic agent of erythrocyte membrane, which in turn opens an interesting avenue in the field of proteomics and glycobiology.     

Low-pH association of proteins with the membranes of intact red blood cells. II. Studies of the mechanism

The low-pH interaction of proteins with erythrocyte membranes has been found to be correlated with pH-induced changes in the erythrocyte membrane. Using a 90 degree lightscattering method it was shown that red blood cell hemolysis was slow between pH 5.8 and 5 (t1/2 above 1 h) but became fast at and below pH 4.7 (t1/2 less than 20 min). At pH 4.7, the presence of glycophorin in the incubation medium inhibited the hemolysis of erythrocytes and this protective effect was found to be dependent on the glycophorin concentration. Electron microscope experiments showed the presence of membrane defects after 10 s incubation at pH 4.6 in the absence of glycophorin in the incubation medium. These defects could further develop into openings with average widths of 14 nm after 1.5 min incubation under the acidic conditions. Fluorescence and flow cytometry studies showed that at pH 4.7, but not at pH 7.4, glycophorin tightly associates with phosphatidylcholine liposomes, and that liposome associated glycophorin molecules are recognized by anti-glycophorin monoclonal antibodies.     

Pneumococci Producing Beta Hemolysis on Agar

Fifty-six strains of pneumococci were studied for hemolysis on blood-agar Twenty-two (39%) of these strains produced beta hemolysis on agar containing horse red cells, six (11%) were beta hemolytic for sheep cells, and none lysed human or rabbit red cells. The substance producing beta hemolysis appeared after 24 hr of anaerobic incubation. Subsequent exposure to air at low temperature (6 to 20 C) for 48 hr was needed to activate it. There was no relation between serological type and beta hemolysis production. This substance appears to be different from the pneumococcal hemolysin previously described.     

Addition of oligosaccharide decreases the freezing lesions on human red blood cell membrane in the presence of dextran and glucose

Although incubation with glucose before freezing can increase the recovery of human red blood cells frozen with polymer, this method can also result in membrane lesions. This study will evaluate whether addition of oligosaccharide (trehalose, sucrose, maltose, or raffinose) can improve the quality of red blood cell membrane after freezing in the presence of glucose and dextran. Following incubation with glucose or the combinations of glucose and oligosaccharides for 3 h in a 37 °C water bath, red blood cells were frozen in liquid nitrogen for 24 h using 40% dextran (W/V) as the extracellular protective solution. The postthaw quality was assessed by percent hemolysis, osmotic fragility, mean corpuscle volume (MCV), distribution of phosphatidylserine, the postthaw 4 °C stability, and the integrity of membrane. The results indicated the loading efficiency of glucose or oligosaccharide was dependent on their concentrations. Moreover, addition of trehalose or sucrose could efficiently decrease osmotic fragility of red blood cells caused by incubation with glucose before freezing. The percentage of damaged cell following incubation with glucose was 38.04 ± 21.68% and significantly more than that of the unfrozen cells (0.95 ± 0.28%, P < 0.01). However, with the increase of the concentrations of trehalose, the percentages of damaged cells were decreased steadily. When the concentration of trehalose was 400 mM, the percentage of damaged cells was 1.97 ± 0.73% and similar to that of the unfrozen cells (P > 0.05). Moreover, similar to trehalose, raffinose can also efficiently prevent the osmotic injury caused by incubation with glucose. The microscopy results also indicated addition of trehalose could efficiently decrease the formation of ghosts caused by incubation with glucose. In addition, the gradient hemolysis study showed addition of oligosaccharide could significantly decrease the osmotic fragility of red blood cells caused by incubation with glucose. After freezing and thawing, when both glucose and trehalose, sucrose, or maltose were on the both sides of membrane, with increase of the concentrations of sugar, the percent hemolysis of frozen red blood cells was firstly decreased and then increased. When the total concentration of sugars was 400 mM, the percent hemolysis was significantly less than that of cells frozen in the presence of dextran and in the absence of glucose and various oligosaccharides (P < 0.01). However, when both glucose and trehalose were only on the outer side of membrane, with increase of the concentrations of sugars, the percent hemolysis was increased steadily. Furthermore, addition of oligosaccharides can efficiently decrease the osmotic fragility and exposure of phosphatidylserine of red blood cells frozen with glucose and dextran. In addition, trehalose or raffinose can also efficiently mitigate the malignant effect of glucose on the postthaw 4 °C stability of red blood cells frozen in the presence of dextran. Finally, addition of trehalose can efficiently protect the integrity of red blood cell membrane following freezing with dextran and glucose. In conclusion, addition of oligosaccharide can efficiently reduce lesions of freezing on red blood cell membrane in the presence of glucose and dextran.     

Sugar transport in reversibly hemolyzed avian erythrocytes.

The technique of reversible hemolysis represents one approach which may be used to study transport regulation in nucleated red cells. After 1 h of incubation at 37 degrees C, 88% of the ghosts regained their permeability barrier to L-glucose. In these ghosts, the carrier-mediated rate of entry of 3-O-methylglucose was more than 10-fold greater than the rate in intact cells. Glyceraldehyde-3-phosphate dehydrogenase prevented ghosts from resealing when it was present at the time of hemolysis. Albumin, lactic dehydrogenase and peroxidase did not have this effect. Sugar transport rate could not be tested in the unsealed ghosts. Two possible mechanisms for the effect of hypotonic hemolysis on sugar transport rate were discussed: (1) altered membrane organization and (2) loss of intracellular compounds which bind to the membrane and inhibit transport in intact cells.     

Exposure to malondialdehyde induces an early redox unbalance preceding membrane toxicity in human erythrocytes

This work investigated the oxidative injury to human red blood cells (RBCs) by the exposure to exogenous malondialdehyde (MDA), in a physiological environment. When a 10% RBC suspension was incubated in autologous plasma, in the presence of 50 λμM MDA, 30% of MDA entered into the cells. A time-course study showed that MDA caused early (30-120 λmin) and delayed (3-18 λh) effects. MDA caused a fast depletion of reduced glutathione, and loss of the glucose-6-phosphate dehydrogenase activity, followed by a decrease of HbO 2 . Accumulation of methemoglobin, and formation of small amounts of hemichrome were later evident. Also, an HbO 2 -derived fluorescent product was measured in the membrane. The redox unbalance was followed by structural and functional damage to the membrane, evident as the formation of conjugated diene lipid hydroperoxides, concurrent with a sharp accumulation of MDA, consumption of membrane vitamin E, and egress of K + ions. SDS--PAGE of membrane proteins showed formation of high molecular weight aggregates. In spite of the marked oxidative alterations, the incubation plasma prevented a substantial hemolysis, even after a 18 λh incubation. On the contrary, the exposure of RBCs to 50 λμM MDA in glucose-containing phosphate saline buffer, resulted in a 16% hemolysis within 6 λh. These results indicate that the exposure to MDA causes a rapid intracellular oxidative stress and potentiates oxidative cascades on RBCs, resulting in their dysfunction.     

The sorting-out of thymidine-labelled chick hypoblast cells in mixed epiblast--hypoblast aggregates.

Tritium-labelled disaggregated chick hypoblast cells were mixed with non-labelled epiblast cells and vice-versa. The mixtures were allowed to aggregate in a gyratory shaker and were transferred on to a solid culture medium for further incubation. The aggregates were fixed after various incubation times, sectioned and examined for sorting-out. There was already a tendency to sort out after 10 h of incubation, a process which was completed after 25 h. The hypoblast cells formed a continuous layer adjacent to the vitelline membrane, while the epiblast cells moved out to form the upper external layer. The position of the two layers was normal as far as the substrate and external environment are concerned, and reversed in relation to their relative position to the vitelline membrane. The hypoblast cells tended to migrate to the margins of the aggregate. The latter phenomenon seems to parallel the migration of hypoblast cells towards the extra-embryonal area during the formation of the primitive streak.     

The Sorting-out of Thymidine-labelled Chick Hypoblast Cells in Mixed Epiblast–Hypoblast Aggregates

Tritium-labelled disaggregated chick hypoblast cells were mixed with non-labelled epiblast cells and vice-versa . The mixtures were allowed to aggregate in a gyratory shaker and were transferred on to a solid culture medium for further incubation. The aggregates were fixed after various incubation times, sectioned and examined for sorting-out. There was already a tendency to sort out after 10 h of incubation, a process which was completed after 25 h. The hypoblast cells formed a continuous layer adjacent to the vitelline membrane, while the epiblast cells moved out to form the upper external layer. The position of the two layers was normal as far as the substrate and external environment are concerned, and reversed in relation to their relative position to the vitelline membrane. The hypoblast cells tended to migrate to the margins of the aggregate. The latter phenomenon seems to parallel the migration of hypoblast cells towards the extra-embryonal area during the formation of the primitive streak.     

Cold-induced hemolysis in a hypertonic milieu

Summary Suspension of human erythrocytes at 37° C in an environment made hypertonic by increasing concentrations of sodium chloride and sucrose was followed by hemolysis when the temperature was lowered to 0° C. Two distinct stages were involved in this hemolytic phenomenon, the first being incubation with hypertonic solute at some temperature above 20° C with an increasing effect up to 45° C, and the second stage consisting of lowering the temperature below 15° C with increasing hemolysis down to 0° C. The rate of cooling was not an important factor, but the presence of ions reduced the extent of cold-induced hemolysis in hypertonic sucrose. No significant release of membrane phospholipid and cholesterol accompanied this hemolysis. The solubilization of membrane protein components was investigated, with some differences appearing on sodium dodecyl sulfate polyacrylamide gel electrophoresis between hypertonic and isotonic supernatants. Spectrin could not be identified in solubilized form. Correlation of the temperatures of note in these studies with results from the literature on other biological effects of temperature-induced phase transitions in membrane lipids strongly points to the conclusion that such transitions are involved in the mechanism of cold-induced hypertonic hemolysis. It is postulated that the hypertonic milieu has resulted in membrane-protein alteration damage which prevents normal adaption to the new physical state of the membrane lipids during cooling.     

Sugar transport in reversibly hemolyzed avian erythrocytes

The technique of reversible hemolysis represents one approach which may be used to study transport regulation in nucleated red cells. After 1 h of incubation at 37°C, 88% of the ghosts regained their permeability barrier to l-glucose. In these ghosts, the carrier-mediated rate of entry of $\text{3-O-}\text{methylglucose}$ was more than 10-fold greater than the rate in intact cells. Glyceraldehyde-3-phosphate dehydrogenase prevented ghosts from resealing when it was present at the time of hemolysis. Albumin, lactic dehydrogenase and peroxidase did not have this effect. Sugar transport rate could not be tested in the unsealed ghosts. Two possible mechanisms for the effect of hypotonic hemolysis on sugar transport rate were discussed: (1) altered membrane organization and (2) loss of intracellular compounds which bind to the membrane and inhibit transport in intact cells.     

Role of the interaction between puerarin and the erythrocyte membrane in puerarin-induced hemolysis

Adverse drug reactions (ADR), especially intravenous hemolysis, have largely limited the application of puerarin injections in clinics. This study investigated the underlying mechanisms of puerarin-induced hemolysis. Our results show that puerarin induced concentration-dependent and time-dependent hemolysis when human erythrocytes were incubated in saline solution with more than 2 mM puerarin for over 2 h. However, incubation in PBS or addition of 1 mM of lidocaine to the saline solution completely abolished the hemolysis. Providing materials that could start ATP synthesis did not reverse the hemolysis, and puerarin did not affect Na⁺–K⁺–ATPase activity. In addition, puerarin (0.1–2 mM) did not cause calcium influx or exhibited pro-oxidant activity in erythrocytes. Puerarin exhibited different influences on the membrane microviscosity of erythrocytes in saline and PBS. Moreover, 1 mM lidocaine inhibited 8 mM puerarin-induced reduction of membrane microviscosity in saline solution. SDS–PAGE analysis of membrane proteins revealed that 2 mM puerarin treatment induced the appearance of several new protein bands but attenuated the expression of protein bands 2.1, 3, 4.1, 4.2 and 5. These results suggest that high concentrations of puerarin-induced hemolysis were associated with the changes of membrane lipids and of the composition of erythrocytes membrane proteins but not with ATP depletion, pro-oxidation and calcium influx. These changes could be related to the intercalation of amphiphilic puerarin at high concentration into the erythrocyte membrane in certain media, resulting in membrane disorganization and, eventually, cytolysis. Hence, in clinics, determining the optimal dose of puerarin is critical to avoid overdosing and ADR.     

Factors controlling the resealing of the membrane of human erythrocyte ghosts after hypotonic hemolysis

Summary In accordance with former observations of Hoffman (1962a), ghost populations obtained by hypotonic hemolysis and subsequent restoration of isotonicity by the addition of alkali salts, were found to be composed of 3 types of ghosts. For our purposes it was useful to distinguish between: (1) ghosts which reseal immediately after hemolysis (type I); these ghosts are incapable of incorporating alkali ions which are added after hemolysis; (2) ghosts which reseal after the addition of alkali ions (type II); salt added to the hemolysate becomes trapped inside these ghosts in the course of the resealing process at temperatures above 0°C; and (3) ghosts which remain leaky regardless of the experimental condition (type III). The discrimination between the various types of ghosts was partly achieved by a kinetic method first devised by Hoffman (1962a), and partly by sucrose density gradient centrifugation.The relative sizes of the 3 fractions depend on the temperature at which hemolysis took place and on the time interval which elapsed between hemolysis and the addition of salt. At 37°C the resealing process is fast. Many of the ghosts reseal before salt can be added to the hemolysate. Hence, the fraction of type I ghosts is high after hemolysis at that temperature. At 0°C resealing is extremely slow. Hence, salt which has been added to the hemolysate at that temperature will enter the ghosts and become trapped during subsequent incubation at 37°C. There are no ghosts of type I and many ghosts of type II (about 60%). Regardless of the temperature at hemolysis, there are always ghosts which do not reseal even after prolonged incubation at 37°C. A method has been designed which permits the preparation of homogeneous populations of type II ghosts.Complexing agents (ATP, EDTA, 2,3-DPG) may prevent the resealing of the ghost membrane. However, they exert this effect only at elevated temperatures and when present in the medium at the instant of hemolysis. At 0°C, the presence of complexing agents in the medium at the instant of hemolysis has no effect on the subsequent resealing at 37°C. The recovery of the ghost membrane takes place in spite of the continued presence of the agents and eventually leads to trapping of these agents inside the resealed ghosts.The experiments support the contention that the complexing agents interact with a membrane constituent which is neither accessible from the inner nor from the outer surface of the cell membrane but becomes exposed during the hemolytic event when the complexing agents penetrate across the membrane. Apparently, at low tempertrures membrane ligands are more successful in competing with the added complexing agents for this constituent than at higher temperatures.Extending former observations of Hoffman, we found that not only Mg⁺⁺ but also Ca⁺⁺ facilitates the resealing process. Perhaps one or the other of the two alkaline earth ions is the membrane constituent which normally participates in the maintenance of the integrity of the red blood cell membrane.     

Exposure to Malondialdehyde Induces an Early Redox Unbalance Preceding Membrane Toxicity in Human Erythrocytes

This work investigated the oxidative injury to human red blood cells (RBCs) by the exposure to exogenous malondialdehyde (MDA), in a physiological environment. When a 10% RBC suspension was incubated in autologous plasma, in the presence of 50 &#117 &#119 M MDA, 30% of MDA entered into the cells. A time-course study showed that MDA caused early (30-120 &#117 min) and delayed (3-18 &#117 h) effects. MDA caused a fast depletion of reduced glutathione, and loss of the glucose-6-phosphate dehydrogenase activity, followed by a decrease of HbO 2 . Accumulation of methemoglobin, and formation of small amounts of hemichrome were later evident. Also, an HbO 2 -derived fluorescent product was measured in the membrane. The redox unbalance was followed by structural and functional damage to the membrane, evident as the formation of conjugated diene lipid hydroperoxides, concurrent with a sharp accumulation of MDA, consumption of membrane vitamin E, and egress of K + ions. SDS--PAGE of membrane proteins showed formation of high molecular weight aggregates. In spite of the marked oxidative alterations, the incubation plasma prevented a substantial hemolysis, even after a 18 &#117 h incubation. On the contrary, the exposure of RBCs to 50 &#117 &#119 M MDA in glucose-containing phosphate saline buffer, resulted in a 16% hemolysis within 6 &#117 h. These results indicate that the exposure to MDA causes a rapid intracellular oxidative stress and potentiates oxidative cascades on RBCs, resulting in their dysfunction.     

Free-radical chain oxidation of rat red blood cells by molecular oxygen and its inhibition by alpha-tocopherol

The oxidation of rat red blood cells (RBC) by molecular oxygen was performed in an aqueous suspension with an azo compound as a free-radical initiator. The RBC were oxidized at a constant rate by a free-radical chain mechanism, resulting in hemolysis. The extent of hemolysis was proportional to the concentration of free radical. alpha-Tocopherol in RBC membranes suppressed the oxidation and hemolysis to produce an induction period. Tocopherol was constantly consumed during the induction period, and hemolysis developed when tocopherol concentrations fell below a critically low level. Among the membrane lipids, phosphatidylethanolamine, phosphatidylserine, and arachidonic acids were predominantly oxidized in the absence of tocopherol. In the presence of tocopherol, however, such lipid changes were suppressed during a 120-min incubation even when hemolysis started. Membrane proteins as well as lipids were oxidized. The formation of proteins with high molecular weight and concomitant decrease of the low-molecular-weight proteins were observed on gel electrophoresis with the onset of hemolysis. This study clearly showed the damage of RBC membranes caused by oxygen radical attack from outside of the membranes, and suggested that membrane tocopherol even below a critically low level could suppress lipid oxidation but that it could not prevent protein oxidation and hemolysis.     

The relationship of membrane lipids to species specific hemolysis by hemolytic factors from Stomoxys calcitrans (L.) (Diptera: Muscidae)

Posterior-midgut homogenate from female stable flies prepared at 12 h after feeding hemolyzed erythrocytes from 6 different mammalian species more readily than homogenate prepared at 22 h. A significant correlation was obtained between the per cent sphingomyelin content of the erythrocyte membrane and the time required for lysis by the 12 h homogenate. Erythrocytes with low sphingomyelin content were more sensitive to lysis than cells with high sphingomyelin. No such correlation exists for hemolysis by 22 h homogenate. Mean corpuscular volume and osmotic fragilities of erythrocytes were not related to hemolysis either by 12 or 22 h homogenate. Determination of phospholipase C and sphingomyelinase activities showed that the hydrolysis rate of phospholipase C in homogenates prepared at 12–14 h was almost twice as much as sphingomyelinase activity. Whereas hydrolysis rates in 22–24 h homogenate were not different and markedly reduced compared to the 12–14 h homogenate. The times required for erythrocyte hemolysis related to the phospholipase C and sphingomyelinase activity profiles suggests that these enzyme activities participate in the in vitro hemolysis of red blood cells. Bovine and human erythrocytes change their biconcave contour into a spiculated spherical shape when they are exposed to midgut homogenate. This shape change is interpreted as a detergent induced modification of the red cell membrane which renders the erythrocytes more vulnerable to hemolysis.     

Changes of red cell phospholipids in β-thalassemia minor

Lipid and phospholipid concentrations were determined in the red cells of β-thalassemia minor patients. A reduced concentration of total lipids and total phospholipids in red cells was found. Phosphatidylcholine and sphingomyelin were increased while phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol concentrations were decreased. These changes are similar to, though less pronounced, than those seen in β-thalassemia major. The relation of these lipids changes, free hemoglobin chains which damage the red cell membrane, and the increased rate of hemolysis is unclear.     

Peroxidation of liposomes in the presence of human erythrocytes and induction of membrane damage of erythrocytes by peroxidized liposomes

Hemolysis (Kobayashi, T., Takahashi, K., Yamada, A., Nojima, S. and Inoue, K. (1983) J. Biochem. 93, 675-680) and shedding of acetylcholinesterase-enriched membrane vesicles (diameter 150-200 nm) were observed when human erythrocytes were incubated with liposomes of phosphatidylcholine which contained polyunsaturated fatty acyl chains. These events occurring on erythrocyte membrane were inhibited by radical scavengers or incorporation of alpha-tocopherol into liposomes, suggesting that lipid peroxidation is involved in the process leading to membrane vesiculation and hemolysis. The idea was supported by findings that generation of chemiluminescence, formation of thiobarbituric acid reactive substance, accumulation of conjugated diene compounds in liposomes and decrease of polyunsaturated fatty acids in liposomes occurred concomitantly during incubation. Hemolysis was also suppressed by the addition of extra liposomes, insensitive to peroxidation, or of serum albumin even after the completion of peroxidation of liposomes. These results suggest that peroxidized lipids, responsible for vesiculation and hemolysis, may be formed first in liposomes and then gradually transferred to erythrocyte membranes. The accumulation of these lipids peroxides may eventually cause membrane vesiculation followed by hemolysis.     

Cytolytic activity of liposomes containing stearylamine

In order to develop the cytotoxic liposome, the cytolytic effect of polycationic liposome was examined. Upon incubation of the stearylamine-containing liposome (stearylamine-liposome) with rabbit erythrocyte, a significant extent of hemolysis was observed. Hemolytic activity of the liposome depends on the amount of stearylamine in the liposome membrane. The plots of the initial rate of hemolysis versus the concentration of stearylamine-liposome showed a sigmoidal curve, suggesting that stearylamine-liposomes act cooperatively on the erythrocyte membrane. Hemolytic activity of stearylamine-liposome was markedly influenced by the composition of hydrocarbon chains of the phospholipids in the liposome membrane, suggesting that the membrane fluidity of stearylamine-liposome is important to evoke the hemolysis. Since the liposomes containing acidic phospholipids inhibited markedly the stearylamine-liposome-caused hemolysis, it is likely that the primary target of stearylamine-liposome is the negatively charged component(s) such as acidic phospholipids on the erythrocyte membrane. Furthermore, stearylamine-liposome induced the release of the intravesicular contents from the liposome made of acidic phospholipids but not from the liposome made of phosphatidylcholine only. These results suggest that stearylamine-liposome interacted with the negative charges of the erythrocyte membrane and eventually damaged the cell. Erythrocytes from rabbit, horse and guinea pig are highly susceptible to stearylamine-liposome but those from man, sheep, cow and chicken are less so.