Studies on the Interaction between Yttrium and Human Erythrocyte Membrane

Yttrium ions promote hemolysis of human erythrocytes, and it's critical hemolytic concentration is 3x10(-5) mol/L. The interactions between Y3+ and human erythrocyte membrane have been studied by SDS-PAGE, CD spectra and fluorescence techniques. The experimental results indicated that the high concentration of Y3+ altered the conformation of human erythrocyte membrane proteins and lead to cross-linking or polymerization among membrane proteins. Y3+ can quench the intrinsic fluorescence of membrane proteins. There are two kinds of binding site's of Y3+ to erythrocyte membrane, the binding capacities (n) and appearance binding constants (K) were determined to be: n(1) = 2.11 x 10(-3) mol/g membrane protein, n(2) = 3.56 x 10(-1) mol/g membrane protein; K-1 = 4.51 x 10(6) L/mol, K-2 = 1.18 x 10(6) L/mol. These results show that Y3+ ions interact strongly with human erythrocyte membrane, and appear obviously cell toxicity.

The investigation for the relationship among serum leptin, erythrocyte membrane Ca^(2+)-ATPase activity and hypertensive disorder complicating pregnancy

Objective： To study the significance of Leptin and the activity of erythrocyte membrane Ca^2＋-ATPase（EMCA） in the development of hypertensive disorder complicating pregnancy. Methods： Radioimmunoassay was used to test the level of serum Leptin, and the activity of EMCA was determined chemically in 38 pregnant women with hypertensive disorder complicating pregnancy and 36 normotensive pregnant women. Results： The level of serum Leptin in hypertensive disorder complicating pregnancy（gestational hypertension： 13.76 ± 3.46 ng/ml; preeclampsia： 15.76 ± 5.47 ng/ml; eclampsia： 18.32 ± 6.38 ng/ml）was significantly higher than that in normotensive pregnant women （11.33 ± 2.93 ng/ml） ,respectively. The average EMCA activity of patients with hypertensive disorder complicating pregnancy （gestational hypertension： 1.65 ± 0.24 μmol·pi/mg.h ; preeclampsia： 1.37 ± 0.19 μ mol·pi/mg·h;eclampsia：1.12 ± 0.14 μmol·pi/mg·h） was significantly lower than that of normotensive pregnant women（1.83 ± 0.38 μ mol·pi/mg·h）,respectively. There was a negative correlation between the level of serum Leptin and the activity of RMCA in hypertensive disorder complicating pregnancy （r = -0.63）. Conclusion： Inhibition of EMCA activity of erythrocyte in hypertensive disorder complicating pregnancy may increase cytoplasmic free calcium, which contributes to the development of hypertensive disorder complicating pregnancy. The negative correlation between the level of serum Leptin and the activity of EMCA, also suggested that serum Leptin and the activity of EMCA may play a role in the development of hypertensive disorder complicating pregnancy.

Interaction of Lanthanum and Calcium with Human Erythrocyte Membranes

The effect of lanthanum and calcium on the structure and function of human erythrocyte membranes was investigated by fluorescence polarization, spin- labeled electron spin resonance (ESR) and laser Raman spectroscopy. The results showed that low concentration of La3+ (0.5 mu mol/L) activated a Little (Na++K+)-ATPase and Mg2+-ATPase activities, and it inhibited obvi ously the ATPase activities with increasing its concentrations. La3+ lowered the lipid fluidity of human erythrocyte membranes and decreased the vibration intensity of alpha-helix of the protein in the Amide I '. The effect of Ca2+ on the lipid fluidity and alpha-helix of the protein in the Amide I ' was smaller than that of La3+.

The Molecular Mechanism in the Damage of Erythrocyte Membrane of the Cows with Hemoglobinuria

The molecular mechanism in the damage of erythrocyte membrane of the cows with hemoglobinuria was studied with the field cases and the group comparison.The field cases were devided into three groups:the hemoglobinuria group(HG),the low phosphorous group(LPG)and the control group(CG).The content of phospholipid constituents in the erythrocyte membrane and the protein constituents in membrane skeleton were determined molecularly and the shape of erythrocyte was examined with the scanning electron microscope.The result showed that:(1)the concentration of phosphatidylethanolamine(PE)in HG was lower significantly than that in LPG and CG;the concentration of sphingomyeline(SM) and phosphatidylcholine(PC)+phosphatidylserine(PS) in HG was significantly lower than that in the other groups;the content of PC+PS was lower and the concentration of SM was higher in LPG with comparing that in CG,the significant positive correlation was observed between the concentration of phosphorus in serum and the concentration of PE,respectively.The significant negative correlation was observed between the content of phosphorus in serum and the content of SM,respectively.(2)the difference of protein constituent in membrane skeleton between LPG and CG was not found,however,the concentration of spectin in band Ⅰ,Ⅱ and the content of protein in band Ⅳ 2 was lower and the concentration of protein in band Ⅲ significantly higher in HG than that in LPG and CG(P<0.01);(3)the form of erythrocyte observed with scanning electron microscope changed from discal to the spinal,to spheric form,to hemolysis ultimately following the reduction of the concentration of phosphorus in serum.It was concluded that the change of the constituent of phospholipid in erythrocyte membrane and protein in membrane skeleton and the form of erythrocyte is the most important factors in hemolysis for hypophosphatemia.

Effect of "Jia Wei Fo Shou San" on Erythrocyte Membrane Calcium,Zinc Concentration in Pregnant Rats with Asymmetrical Intrauterine Growth Retardation Induced by Passive Smoking

Using experimental model of pregnant rats with asymmetrical intrauterine fetal growth retardation induced by passive smoking, the effects of natural herb 'Jia Wei Fo Shou San' on erythrocyte membrane calcium, zinc concentration were observed by atomic absorption spectrophotometry. The results showed that the mean fetal birth weight, zinc concentration of erythrocyte membrane were found to be decreased in the model group as compared with the control group (P＜0. 01, P＜0. 01). On the other hand, the element of calcium onto erythrocyte membrane were higher in model group than that in control group(P＜0. 05). These changes were significantly mild in the treated group and were similar to those of the control group (P＜0.05). Furthermore,our findings indicated that the zinc concentration of erythrocyte membrane seems to be positively correlated with the birth weight(P＜0. 01). Calcium composition of red cell membrane showed a significant negative relation to the birth weight (P＜0.05). Our results provided an experimental evidence that normal concentrations of calcium and zinc onto erythrocyte play an important part in fetal growth. One of the mechanisms of 'Jia Wei Fo Shou San' in improving fetal growth may have something to do with modulation of erythrocyte calcium,zinc element,thereby protecting bio-functions of erythrocyte and promoting blood circulation.

The Relationships between Erythrocyte Membrane n-6 to n-3 Polyunsaturated Fatty Acids Ratio and Blood Lipids and C-reactive Protein in Chinese Adults:An Observational Study

Objective To investigate the relationships between erythrocyte membrane n-6：n-3 PUFAs ratio and blood lipids and high sensitivity C-reactive protein （hs-CRP）. Methods The Chinese and a observational study consisted of a population-based cross-sectiona subsequent 1-year follow-up study of 171 subjects with the fasting cholesterol of 5.13-8.00 mmol/L. study of 456 plasma total Results In the cross-sectional analysis, plasma low-density lipoprotein cholesterol （LDL-c） had a significant and negative association with the erythrocyte membrane n-6：n-3 PUFAs ratio （P for trend=0.019） after adjusting for sex, age and total PUFA percentage. In the follow-up study, 171 subjects were categorized into quartiles by the changes of n-6：n-3 ratio in erythrocyte membrane （△=month 12-month 0）. In the top quartile whose ratios of n-6：n-3 increased by an average of 1.25 during the follow-up, the LDL-c-lowering extent was 3.3 times of that in the lowest quartile whose ratios of n-6：n-3 decreased by an average of 1.13 （-1.07 mmol/L v.s. -0.32 mmol/L）. The hsCRP decreased by 0.11 mg/dL in the lowest quartile while increasing by 0.10 mg/dL in the top quartile （P for difference=0.052）. Conclusion Our results suggested that the balance between n-6 and n-3 fatty acids may optimize the cardiovascular benefits from dietary PUFAs.

Study on Phospholipid Composition of Erythrocyte Membrane in Hypophosphatemic Cows

The phospholipid constituents of the erythrocyte membrane of cows in hypophosophorus were detected with the field cases and the group comparison. The cows were divided into three groups: the hemoglobinuria group (HN), the hypophosphatemia group (HP) and the control group (CK). The content of the phospholipid constituent in HN and HP obviously changed: phosphatidylethaanolamine (PE) content in HN was significantly lower than that in HP and CK; but sphingomyline (SM) and phosphatidycholine (PC) + phosphatidylserine (PS) content in HN were significantly higher than that in the two other groups; in comparison between HP and CK, PC + PS content was lower and SM content was higher in HP; significant positive correlation and negative correlation were observed between serum phosphorus and PE content, serum phosphorus and SM content respectively.

Effect of Huoxuequyu Recipe on Erythrocyte Membrane Ca^(2+)-ATPase Activity in Pregnant Rats with Asymmetrical Intrauterine Growth Retardation Induced by Passive Smoking

The effect of Huoxuequyu recipe on erythrocyte membrane Ca2+-ATPase activity in pregnant rats with passive smoking induced asymmetrical intrauterine growth retardation(IUGR)was observed.The rats were divided into three groups:control group,model group and treated group.The fetal mean birth weight and erythrocyte membrane Ca2+-ATPase activity were found to be decreased in the model group as compared with the control and treated groups.There was a significant difference between the model group and the control group(P<0.01),while no significant difference existed between the treated group and the control group(P>0.05).Furthermore,the findings indicated that the erythrocyte membrane Ca2+-ATPase activity seem to be positively correlated with the birth weight(P<0.05).On the basis of our observation,it is believed that the Huoxuequyu decoction could increase erythrocyte membrane Ca2+-ATPase activity and promote blood circulation, thereby exerting a beneficial effect on fetal development.

Effect of Huoxuequyu Recipe on Erythrocyte Ultrastructure and Membrane ATPase Activity in Rats with Passive Smoking

The effect of 'Huoxuequyu' recipe on erythrocyte membrane Ca2+ATPase activity, Na+-K+-ATPase activity and erythrocyte ultrastructure in rats exposed to passive smoking were observed. The erythrocyte membrane Ca2+-ATPase activity and Na+-K+-ATPase activity were found to be decreased in the model group as compared with the control group (P<0.01, P<0.01), while no significant difference existed between the treated group and the control group (P>0.05). Our results also showed that there were more deformed red blood cells in model group than in control group under TCM and SEM (P<0.0001). No significant difference was found between control group and treated group (P>0.05). Furthermore,these findings indicated that 'Huoxuequyu' recipe , a prepared natural herbal medicine, may be involved in modulation of the activity of erythrocyte membrane enzymes,thereby protecting erythrocyte membrane, so as to improve the erythrocyte function.

SUPEROXIDE DISMUTASE ACTIVITY AND MEMBRANE LIPIDS COMPOSITION OF ERYTHROCYTES IN PATIENTS WITH DILATEDCARDIOMYOPATHY

Objective To rurther conflrm the role or lipld-peroxldation caused by oxygen free radicals injury played in the pathogenesis of dllsted cardlomypathy. MethOds The superoxide dismutase activities and lipids composltion of erythrocytes in 18 patients with dilated cardiomyopathy and 16 healthy controls were measured. Results Superoxide dlsmutase(SOD) activites of erythrocytes were lower in dilated cardiomyopathy(DCM) patients than that in healthy controls (P <o. oo1 ). The lipids composition of erythrocytes has changed in the DCM patients compared with healthy controls: total liplds changed little (P >o. o5); total phospholipids were lower, but not significantly (P>o. o5): total cholesterol increased significantly (P <o. o5). The cholesterol to phospholipids molecular ratio of erythrocyte membrane has increased remarkably (P >o. o5). Conclusion It can be supposed that decreased SOD activitles play an important role in the damage or membrane system and the pathogensis of DCM.

Effects of L.F04,the Active Fraction of Lycopus lucidus, on Erythrocytes Rheological Property

Objective: To study the effects of L.F04, the active fraction of Lycopus lucidus, on erythrocytes rheological property so as to investigate its mechanism in promoting blood circulation and removing blood stasis. Method: The effects of L.F04 (used for treatment for 10 days in different dosages) on deformability, aggregation and membrane liquidity of erythrocytes (MLE) as well as whole blood apparent viscosity (η_b) were examined on the basis of rat model of blood-stasis syndrome induced by venous injection of high molecular weight dextran. Result: As compared with the normal control group, the model group's RBC deformability and MLE were lower, and the aggregation of erythrocytes and η_b were higher. Compared with the model group, both L.F04 0.612g/kg and 0.306g/kg showed significant effect in improving deformability and inhibiting aggregation of red blood cells (RBC) and reducing blood viscosity. The trend of improving MLE was also shown. Conclusion: L.F04 could significantly improve the abnormal rheological property of erythrocytes.

Relationship between the Contents of MDA, the Activity of SOD in Serum of the Milk Goat with Fluorosis and the Erythrocytic Membrane Liquidity

To research the relation among the erythrocytic membrane.liquidity and the contents of MDA, the activity of SOD in serum of the milk goat with fluorosis. An animal model with fluorosis was constructed, and the fluorescent probe technique of DPH was used to measue the erythrocytic membrane liquidity. At the same time, the contents of MDA and the activity of SOD in serum were measured. The results showed that the erythrocytic membrane liquidity in the control group and flurosis group were 5.6742 ± 0.4417 and 3.7248 ± 0.4521 （P 〈0.01） respectively, the contents of MDA in serum were 2.0408 ± 0.198 and 4.494± 0.438 （P 〈0.01） respectively, the activities of SOD were 175.638 ± 22.201 and 113.714 ± 34.258 （P 〈0.01） respectively. The correlation analysis indicated that the relation between the activity of SOD and the liquidity of erythrocytic membrane was positive correlation （ r= 0.7321, P 〈0.05）, whereas the relation between the contents of MDA and the liquidity of erythrocytic membrane was negative correlation （r = -0.6438, P 〈0.01）. The erythrocytic membrane liquidity decreased in milk goat with fluorosis, which played a role in the occurrence and development of the fluorosis. There was correlation among the erythrocytic membrane liquidity and the contents of MDA, the activity of SOD.

Erythrocyte membrane encapsulated gambogic acid nanoparticles as a therapeutic for hepatocellular carcinoma

Gambogic acid(GA)is a potential clinical anticancer drug that can exert antitumor effects via various molecular mechanisms.Notwithstanding,GA’s low water solubility,poor stability,short half-life,and unavoidable toxic side effects have significantly hampered its clinical application.Erythrocyte membranecoated nanoparticles(RBCM-NPs)improve drug’s physicochemical properties,biocompatibility,and pharmacokinetic behaviors,allowing for long-term drug circulation and passive targeting.In this study,a novel biomimetic drug delivery system(DDS)against hepatocellular carcinoma was prepared by covering RBCM on GPP-NPs(GA-loaded m PEG-PLA NPs)to develop the RBC@GPP-NPs.In comparison to RBCM-free nanoparticles and free GA,RBC@GPP-NPs improved the drug’s water solubility,stability,safety,and antitumor activity in vivo.We expect that this bionic nanoparticle composite can expand the clinical applicability of GA and provide a feasible solution for the research and development of GA’s nano-formulation.

Erythrocyte membrane protein abnormalities in β-thalassemia of the Li nationality in Hainan

Objective To determine the composition of abnormal red cell membrane skeletin. Methods By sodium dodecyl sulphate polyacrylamide gel electrophoresis of ghostcorpuscles, we quantified the amount of protein by densitometric evaluation.Results The results showed that in β-thalassernia, the amount of spectrin, 4.5 protein and globin significantly increased compared with the controls (26.05 + 1.46, 21.69 + 1.86; 22.87 + 5.61, 12.99 +2.33; 15.23+3.31 and 4.97+2.73, respectively, P＜0.05).Conclusion These data suggest that the erythrocyte membrane protein composition matched with globin in patients with β-thalassemia of the racial Li minority are different from the normal control. These factors increase rigidity but decrease deformability of the β-thalassemic red cell membrane, which may lead to hemolytic anemia.

Glycophorin variants and contents of sialic acid and total sulfhydryl groups on erythrocyte membranes of residents in a malaria hyperendemic area

Abstract Objective To conduct a screening survey of glycophorin (GP) variants and observe the content changes of sialic acid (SA) and total sulfhydryl (SH) groups on the erythrocyte membranes among residents in a tertian malaria hyperendemic area of Guizhou Province. Methods GP variants were detected in the erythrocyte hemolysates of 173 local residents at two villages of Libo County by SDS PAGE on 10% to 15% gradients gel and Western immunoblotting. Their SA and total SH group contents were estimated in erythrocyte membranes by spectrophotometric methods. 114 healthy subjects in Changsha and 49 individuals at a neighbouring village of the above area showing low morbidity of malaria served as normal and endemic controls respectively. Results Three distinct types of GP variants were found among 19 propositi in this hyperendemic area. The incidence of GP variants was 7.9% (8/101) at Yaolu Village whose population was mainly composed of Yao ethnic group;while that of Buyi ethnic group at Maolan Village was higher (15.3%; 11/72).The erythrocyte membrane contents of SA in residents at both villages exhibited a very significant tendency of decline (P<0.01), whereas those of total SH groups increased prominently in residents of Yaolu Village only (P<0.05). Conclusions The frequency of GP variants in this hyperendemic area does not depend upon the severity of malarial prevalence. The evident reduction of SA contents in the residents may be related to the breaking down of the SA residues on membrane GPs by the invasion of Plasmodium vivax.

The critical pressure for driving a red blood cell through a contracting microfluidic channel

When a red blood cell （RBC） is driven by a pressure gradient through a microfluidic channel, its passage or blockage provides a measure of the rigidity of the cell. This has been developed as a means to separate RBCs according to their mechanical properties, which are known to change with pathological conditions such as malaria infection. In this study, we use numerical simulations to establish a quantitative connection between the minimum pressure needed to drive an RBC through a contracting microfluidic channel and the rigidity of the cell membrane. This provides the basis for designing such devices and interpreting the experimental data.

Erythrocyte membrane Ca^(2+)-ATPase inhibited by oxidized low density lipoprotein

Oxidized low density lipoprotein (LDL) has been shown to inhibit the activity of platelet plasma mambrane Ca^2+ ATPase, and induce changes of factin in endothelial cells. Since the deformability of human erythrocytes are closely related to the calcium metabolism and the stability of cytoskeleton, the influence of oxidized LDL on plasma membrane Ca^2+ ATPase and plasma membrane fluidity were studied in human erythrocytes. Our in vitro experiments demonstrated that oxidized LDL, but not native LDL, inhibits the activity of Platelet Research Unit, Institute of Anatomy, University of Münster, Germany (Zhao B, Filler TJ and Dierichs R) Shanghai Fourth People's Hospital, Shanghai, China (Yu H) Department of Biochemistry, University of Louisville, Kentucky, USA (Dean W)Ca^2+ ATPase in purified erythrocyte plasma membrane (P<0.01). Since no change in the membrane fluidity was detected in the erythrocyte plasma membrane exposed to native LDL and oxidized LDL as estimated by steady state by trimthylammonium diphenylhexatriene (TMA DPH) anisotropy, oxidized LDL did not affect the Ca^2+ ATPase by grossly changing the erythrocyte deformability probably by interfering the cytosolic calcium and then altering the cytoskeleton. The deformability of erythrocytes is important in microcirculation. A better understanding of the interactions between oxidized LDL, erythrocytes, platelets and endothelial cells can prevent cardiovascular diseases.

Experimental study of alternations in erythrocyte membrane lipid peroxidation and fluidity induced by high-cholesterol diet in rabbits

Background Animal models of hyperlipidemia were established by feeding rabbits with high-cholesterol diet, and the changes in structure and function of cell membrane in rabbits were also reduced by hyperlipidemia. Thus, the alternations in erythrocyte membrane lipid peroxidation （EMLP） and fluidity in rabbits induced by high-cholesterol diet were researched by us. Methods Fourteen rabbits were subjected to high-cholesterol diet （cholesterol 2 g/d） and the other 14 rabbits to common diet everyday for consecutive two months, plasma total cholesterol （TC）, and blood lipids as well as EMLP and fluidity were measured before and after the feeding. Results Compared with the feeding before, levels of TC and low density lipoprotein- cholesterol （LDL-C） were significantly raised, those of erythrocyte membrane low density lipoprotein- cholesterol （MLDL-C）, membrane conjugated diene （MCD）, erythrocyte malonaldehyde （RMDA） were significantly increased, while those of erythrocyte superoxide dismutase （R-SOD）, membrane fluidity （M-Flu） and membrane high density lipoprotein-cholesterol （MHDL-C） were significantly decreased in experimental group, and there were no changes in control group. Conclusions High-cholesterol diet induces lipid peroxidation and lower fluidity of erythrocyte membrane.

Antigenic variation and cytoadherence of PfEMP1 of Plasmodium falciparum infected erythrocyte from malaria patients

To approve a theoretical basis for the molecular pathogenesis of human cerebral malaria and treatment with prevention Methods The blood samples were collected from 24 patients with cerebral malaria, 143 with falciparum malaria, 34 with vivax malaria and 20 healthy controls from the endemic areas of Yunnan Province, China Using the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) technique, we determined the molecular mass (Mr) of these Plasmodium falciparum (P falciparum) erythrocyte membrane protein 1 (PfEMP1) molecules Results Our findings indicate that higher molecular mass (260?kDa-320?kDa) forms of PfEMP1 were expressed on parasitized erythrocyte (PE) from human cerebral malaria patients Compared with PfEMP1 expressed on PE from human cerebral malaria patients, the expression of PfEMP1 and Plasmodium vivax (P vivax) erythrocyte membrane protein 1 (PvEMP1) on PE from falciparum malaria patients and vivax malaria patients did not have multiple bands of PfEMP1 of ≥260?kDa, but had a PfEMP1 with molecular mass of 240?kDa and a PvEMP1 with molecular mass of 180?kDa band separately Healthy controls expressed an EMP of molecular mass of 140?kDa Conclusion Results confirm the antigenic variation of higher molecular mass of PfEMP1 whose molecular mass is equal to or exceeds 260?kDa-320?kDa on PE of patients with cerebral malaria Our results show that the binding of large antigenic variability PfEMP1 molecular mass of 260?kDa-320?kDa on PE from human cerebral malaria patients with diverse receptor molecules on the endothelial cell (EC) of the cerebral microvessels may be involved in the molecular pathogenesis of cerebral malaria

Cesium＇s Affects on Morphological Changes of Human Erythrocytes

Cesium could play a toxic role in several pathological processes. Atomic force microscopy （AFM） was used to study morphological changes of human erythrocytes after incubating with different concentrations of CsCI, and the Raman spectra were used to study the effects of CsCl on the chemistry components of erythrocyte membrane. The AFM images showed that the ＂domain structures＂ that appeared after incubation with higher concentration of CsCl （150 mmol-L-1）, are featured by the particles aggregated to form ranges and the separations among them enlarged to gorges, and this change may increase the permeability of cell membranes. The Raman results showed that the polar part of membrane phospholipid become more order and with the increasing of the concentration of CsCl, the longitudinal order of nonpolar parts first decreased and then increased. It is concluded that the aggregation of mem- brane proteins and the order changes of the phospholipid cause a change in the distribution and conformation of the phospholipid membrane. And the effects of CsCl on the erythrocyte membrane are mainly dependent on its concentration.