Effect of dietary zinc deficiency on the endogenous phosphorylation and dephosphorylation of rat erythrocyte membrane

International Nuclear Information System (INIS)

Paterson, P.G.; Allen, O.B.; Bettger, W.J.

1987-01-01

The effect of dietary zinc deficiency on patterns of phosphorylation and dephosphorylation of rat erythrocyte membrane proteins and erythrocyte filterability was examined. Weanling male Wistar rats were fed an egg white-based diet containing less than 1.1 mg zinc/kg diet ad libitum for 3 wk. Control rats were either pair-fed or ad libitum-fed the basal diet supplemented with 100 mg zinc/kg diet. Net phosphorylation and dephosphorylation of erythrocyte membrane proteins were carried out by an in vitro assay utilizing [gamma- 32 P]ATP. The membrane proteins were subsequently separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the 32 P content of gel slices was counted by Cerenkov counting. Erythrocyte filterability was measured as the filtration time of suspensions of erythrocytes, both untreated and preincubated with diamide, under constant pressure. Erythrocyte ghosts from zinc-deficient rats demonstrated greater dephosphorylation of protein bands R1 plus R2 and R7 than pair-fed rats and greater net phosphorylation of band R2.2 than pair-fed or ad libitum-fed control rats (P less than 0.05). Erythrocytes from ad libitum-fed control rats showed significantly longer filtration times than those from zinc-deficient or pair-fed control rats. In conclusion, dietary zinc deficiency alters in vitro patterns of erythrocyte membrane protein phosphorylation and dephosphorylation, whereas the depression in food intake associated with the zinc deficiency increases erythrocyte filterability. 71 references

Blood-group-Ii-active gangliosides of human erythrocyte membranes

International Nuclear Information System (INIS)

Feizi, T.; Childs, R.A.; Hakomori, S.-I.; Powell, M.E.

1978-01-01

More than ten new types of gangliosides, in addition to haematoside and sialosylparagloboside, were isolated from human erythrocyte membranes. These were separated by successive chromatographies on DAEA-Sephadex, on porous silica-gel columns and on thin-layer silica gel as acetylated compounds. Highly potent blood-group-Ii and moderate blood-group-H activities were demonstrated in some of the ganglioside fractions. The gangliosides incorporated into chlolesterol/phosphatidylcholine liposomes stoicheiometrically inhibited binding of anti-(blood-group-I and i) antibodies to a radioiodinated blood-group-Ii-active glycoprotein. The fraction with the highest blood-group-I activity, I(g) fraction, behaved like sialosyl-deca- to dodeca-glycosylceramides on t.l.c. Certain blood-group-I and most of the i-determinants were in partially or completely cryptic form and could be unmasked by sialidase treatment. Thus the I and i antigens, which are known to occur on internal structures of blood-group-ABH-active glycoproteins in secretions, also occur in the interior of the carbohydrate chains of erythrocyte gangliosides. (author)

Influence of ionizing radiation on the spatial structure of erythrocyte membranes

International Nuclear Information System (INIS)

Dreval', V.Yi.; Syichevs'ka, L.V.; Doroshenko, A.O.; Roshal', O.D.

1998-01-01

Influence of gamma-radiation of doses of 10, 10 2 , 5 centre dot 10 2 , and 10 3 Gy on the structure of the protein-lipid complexes of erythrocyte membranes is investigated. The allotment of fluorescence of protein in the donor-acceptor pair of tryptophan-pyrene and the distance of protein from the surface of the lipid bilayer of a membrane are determined by the method of inductive-resonance transfer of energy. The pair is localized at the distance of above 3.2 nm from lipids. We find that the action of irradiation changes the space structure of proteins and lipids of the erythrocyte membrane

E.s.r. radiation studies of erythrocyte membrane-haemoglobin interaction

International Nuclear Information System (INIS)

Koter, M.; Kowalska, M.A.; Leyko, W.; Waterman, M.

1977-01-01

The dependence of the yield of free radicals in gamma-irradiated, freeze-dried erythrocyte membranes on their haemoglobin content was studied. A non-monotonous relationship was found, different from that observed in mixtures of freeze-dried membranes and haemoglobin, which suggests the existence of radiation-energy transfer between the membranes and bound haemoglobin. (author)

Aspectos estruturais da membrana eritrocitária Structural aspects of the erythrocyte membrane

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Priscila Murador

2007-06-01

ócito e é ainda responsável pela estabilidade sob mecanismos de estresse. Essa revisão da membrana eritrocitária é importante para um melhor entendimento das reações transfusionais, onde a formação de anticorpos contra antígenos de alta freqüência dificulta a transfusão compatível. O estudo da diversidade antigênica, a caracterização bioquímica de diferentes proteínas trará uma contribuição para o estabelecimento da saúde, assim como para o diagnóstico, desenvolvimento de tecnologias, como a produção de anticorpos monoclonais e conduta terapêutica para muitas enfermidades.This article describes the structures and functions of the erythrocyte membrane and its importance in transfusional medicine. The erythrocyte membrane is one of the best known membranes in terms of structure, function and genetic disorders. As any other plasma membrane, it mediates transport functions. It also provides the erythrocytes with their resilience and deformability. According to the International Society of Blood Transfusion (ISBT, more than 500 antigens are expressed in the erythrocyte membrane, and around 270 are involved in transfusion reaction cases and hemolytic diseases of the fetus and newborn. In the ISBT classification, the high frequency series is represented by antigens in more than 99% of population (high prevalence antigen. In transfusion, the absence of these antigens determines severe problems as for example, one woman without the P antigen suffered 6 repetitive miscarriages due to placental insufficiency, which was caused by an antibody formed against the absent P antigen. Some important erythrocyte membrane proteins are described here including Band 3, Glycophorins and spectrin. The most abundant integral membrane protein is Band 3 and its main function is to mediate exchange of chloride and bicarbonate anions across the plasma membrane. The second most abundant integral membrane protein in the human erythrocyte is sialoglycoprotein glycophorin A (GPA

Solubilization of human erythrocyte membranes by ASB detergents

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C.C. Domingues

2008-09-01

Full Text Available Understanding the membrane solubilization process and finding effective solubilizing agents are crucial challenges in biochemical research. Here we report results on the interaction of the novel linear alkylamido propyl dimethyl amino propanosulfonate detergents, ASB-14 and ASB-16, with human erythrocyte membranes. An estimation of the critical micelle concentration of these zwitterionic detergents (ASB-14 = 100 µM and ASB-16 = 10 µM was obtained using electron paramagnetic resonance. The amount of proteins and cholesterol solubilized from erythrocytes by these detergents was then determined. The hemolytic activities of the ASB detergents were assayed and the detergent/lipid molar ratios for the onset of hemolysis (Re sat and total lysis (Re sol were calculated, allowing the determination of the membrane binding constants (Kb. ASB-14 presented lower membrane affinity (Kb = 7050 M-1 than ASB-16 (Kb = 15610 M-1. The amount of proteins and cholesterol solubilized by both ASB detergents was higher while Re sat values (0.22 and 0.08 detergent/lipid for ASB-14 and ASB-16, respectively were smaller than those observed with the classic detergents CHAPS and Triton X-100. These results reveal that, besides their well-known use as membrane protein solubilizers to enhance the resolution of two dimensional electrophoresis/mass spectrometry, ASB-14 and ASB-16 are strong hemolytic agents. We propose that the physicochemical properties of ASB detergents determine their membrane disruption efficiency and can help to explain the improvement in the solubilization of membrane proteins, as reported in the literature.

Determination of CFTR densities in erythrocyte plasma membranes using recognition imaging

International Nuclear Information System (INIS)

Ebner, Andreas; Hinterdorfer, Peter; Nikova, Dessy; Lange, Tobias; Bruns, Reimer; Oberleithner, Hans; Schillers, Hermann; Haeberle, Johannes; Falk, Sabine; Duebbers, Angelika

2008-01-01

CFTR (cystic fibrosis transmembrane conductance regulator) is a cAMP-regulated chloride (Cl - ) channel that plays an important role in salt and fluid movement across epithelia. Cystic fibrosis (CF), the most common genetic disease among Caucasians, is caused by mutations in the gene encoding CFTR. The most predominant mutation, F508del, disturbs CFTR protein trafficking, resulting in a reduced number of CFTR in the plasma membrane. Recent studies indicate that CFTR is not only found in epithelia but also in human erythrocytes. Although considerable attempts have been made to quantify CFTR in cells, conclusions on numbers of CFTR molecules localized in the plasma membrane have been drawn indirectly. AFM has the power to provide the needed information, since both sub-molecular spatial resolution and direct protein recognition via antibody-antigen interaction can be observed. We performed a quantification study of the CFTR copies in erythrocyte membranes at the single molecule level, and compared the difference between healthy donors and CF patients. We detected that the number of CFTR molecules is reduced by 70% in erythrocytes of cystic fibrosis patients

Determination of CFTR densities in erythrocyte plasma membranes using recognition imaging

Energy Technology Data Exchange (ETDEWEB)

Ebner, Andreas; Hinterdorfer, Peter [Institute for Biophysics, University of Linz, A-4040 Linz (Austria); Nikova, Dessy; Lange, Tobias; Bruns, Reimer; Oberleithner, Hans; Schillers, Hermann [Institute of Physiology II, University of Muenster, D-48149 Muenster (Germany); Haeberle, Johannes; Falk, Sabine; Duebbers, Angelika [Department of Pediatrics, University Hospitals of Muenster, D-48149 Muenster (Germany)], E-mail: schille@uni-muenster.de

2008-09-24

CFTR (cystic fibrosis transmembrane conductance regulator) is a cAMP-regulated chloride (Cl{sup -}) channel that plays an important role in salt and fluid movement across epithelia. Cystic fibrosis (CF), the most common genetic disease among Caucasians, is caused by mutations in the gene encoding CFTR. The most predominant mutation, F508del, disturbs CFTR protein trafficking, resulting in a reduced number of CFTR in the plasma membrane. Recent studies indicate that CFTR is not only found in epithelia but also in human erythrocytes. Although considerable attempts have been made to quantify CFTR in cells, conclusions on numbers of CFTR molecules localized in the plasma membrane have been drawn indirectly. AFM has the power to provide the needed information, since both sub-molecular spatial resolution and direct protein recognition via antibody-antigen interaction can be observed. We performed a quantification study of the CFTR copies in erythrocyte membranes at the single molecule level, and compared the difference between healthy donors and CF patients. We detected that the number of CFTR molecules is reduced by 70% in erythrocytes of cystic fibrosis patients.

Cross-sectional associations of cortical β-amyloid with erythrocyte membrane long-chain polyunsaturated fatty acids in older adults with subjective memory complaints.

Science.gov (United States)

Hooper, Claudie; De Souto Barreto, Philipe; Payoux, Pierre; Salabert, Anne Sophie; Guyonnet, Sophie; Andrieu, Sandrine; Vellas, Bruno

2017-08-01

Omega-3 (n-3) and 6 (n-6) polyunsaturated fatty acids (PUFAs) have been associated with reduced cognitive decline in observational studies. Hence, we examined the cross-sectional associations between cortical β-amyloid (Aβ) and erythrocyte membrane PUFAs in 61 non-demented elderly individuals reporting subjective memory complaints from the Multidomain Alzheimer Preventive Trial placebo arm. Cortical-to-cerebellar standard uptake value ratios were obtained using [ 18 F] florbetapir positron emission tomography. Fatty acids were measured in erythrocyte membranes by gas chromatography. Associations were explored using adjusted multiple linear regression models and were considered significant at p ≤ 0.005 after correction for multiple testing (10 comparisons). We found no significant associations between cortical Aβ and erythrocyte membrane PUFAs. The associations closest to significance after adjustment were those between Aβ and erythrocyte membrane arachidonic acid (without apolipoprotein E status adjustment: B-coefficient, 0.03; CI, 0.01, 0.05; p = 0.02. Including Apolipoprotein E adjustment: B-coefficient, 0.03; CI, 0.00, 0.06; p = 0.04) and Aβ and erythrocyte membrane linoleic acid (without apolipoprotein E status adjustment: B-coefficient, -0.02; CI, -0.04, 0.00; p = 0.02. Including Apolipoprotein E adjustment: B-coefficient, -0.02; CI, -0.04, 0.00; p = 0.09). Furthermore, the association between Aβ and erythrocyte membrane arachidonic acid seemed to be specific to Apolipoprotein E ε4 non-carriers (B-coefficient 0.03, CI: 0.00, 0.06, p = 0.03, n = 36). In contrast, no association was found between Aβ and erythrocyte membrane linoleic acid in Apolipoprotein E ε4 stratified analysis. Investigating the relationships between Aβ and PUFAs longitudinally would provide further evidence as to whether fatty acids, particularly arachidonic acid and linoleic acid, might modulate cognition through Aβ-dependent mechanisms. © 2017 International

Nuclear magnetic resonance investigation of erythrocyte membranes in chronic myeloproliferative disorders.

Science.gov (United States)

Morariu, V V; Petrov, L

1986-07-01

The temperature dependence of the apparent water diffusional exchange through erythrocyte membranes in cases of policitemia vera, chronic granulocytic leukemia and primary myelofibrosis was measured by using a nuclear magnetic resonance method in the presence of Mn2+. The thermal transition shifted to lower temperatures in all cases, regardless of the stage of the disease, suggesting a structural alteration of the membrane. The shift of transition indirectly suggests a lower penetration of the erythrocytes by Mn2+. The water exchange time at 37 degrees C also increased, mainly in the blast crisis; it seems to have a prognostic value of some clinical interest. No simple correlation of the water exchange and the following clinical investigations was observed: the white count, the percentage of promyelocites and myeloblasts, the sedimentation rate of blood, the osmotic fragility of erythrocytes, the total concentration of proteins, albumin and immunoglobulins, respectively, in plasma.

Effect of gamma irradiation on membranes of normal and pathological erythrocytes (beta-thalassemia)

International Nuclear Information System (INIS)

Sportelli, L.; Bonincontro, A.; Cametti, C.; Consiglio Nazionale delle Ricerche, Rome

1987-01-01

The influence of ionizing radiation on the membrane of human normal erythrocytes has extensively been studied and a variety of effects including changes in the cation fluxes or in non-electrolytes permeability, in membrane fluidity, in peroxidation of unsaturated lipids as well as chemical composition or structural modifications has been observed. However, only few studies deal with the effects of ionizing radiation on pathological red blood cells. In this work, we have investigated by means of electron spin resonance (ESR) spectroscopy the effects of 60 Co γ-radiation on the normal and homozygous β-thalassemic human erythrocyte membranes. (orig.)

Erythrocyte membrane modified janus polymeric motors for thrombus therapy

NARCIS (Netherlands)

Shao, Jingxin; Abdelghani, Mona; Shen, Guizhi; Cao, Shoupeng; Williams, David S.; van Hest, Jan C.M.

2018-01-01

We report the construction of erythrocyte membrane-cloaked Janus polymeric motors (EM-JPMs) which are propelled by near-infrared (NIR) laser irradiation and are successfully applied in thrombus ablation. Chitosan (a natural polysaccharide with positive charge, CHI) and heparin (glycosaminoglycan

Effects of flaxseed oil on anti-oxidative system and membrane deformation of human peripheral blood erythrocytes in high glucose level.

Science.gov (United States)

Yang, Wei; Fu, Juan; Yu, Miao; Huang, Qingde; Wang, Di; Xu, Jiqu; Deng, Qianchun; Yao, Ping; Huang, Fenghong; Liu, Liegang

2012-07-08

The erythrocyte membrane lesion is a serious diabetic complication. A number of studies suggested that n-3 fatty acid could reduce lipid peroxidation and elevate α- or γ-tocopherol contents in membrane of erythrocytes. However, evidence regarding the protective effects of flaxseed oil, a natural product rich in n-3 fatty acid, on lipid peroxidation, antioxidative capacity and membrane deformation of erythrocytes exposed to high glucose is limited. Human peripheral blood erythrocytes were isolated and treated with 50 mM glucose to mimic hyperglycemia in the absence or presence of three different doses of flaxseed oil (50, 100 or 200 μM) in the culture medium for 24 h. The malondialdehyde (MDA) and L-glutathione (GSH) were measured by HPLC and LC/MS respectively. The phospholipids symmetry and membrane fatty acid composition of human erythrocytes were detected by flow cytometry and gas chromatograph (GC). The morphology of human erythrocyte was illuminated by ultra scanning electron microscopy. Flaxseed oil attenuated hyperglycemia-induced increase of MDA and decrease of GSH in human erythrocytes. Human erythrocytes treated with flaxseed oil contained higher C22:5 and C22:6 than those in the 50 mM glucose control group, indicating that flaxseed oil could reduce lipid asymmetric distribution and membrane perturbation. The ultra scanning electron microscopy and flow cytometer have also indicated that flaxseed oil could protect the membrane of human erythrocytes from deformation at high glucose level. The flaxseed oil supplementation may prevent lipid peroxidation and membrane dysfunction of human erythrocytes in hyperglycemia.

Fluorescence energy transfer on erythrocyte membranes

International Nuclear Information System (INIS)

Fuchs, H.M.; Hof, M.; Lawaczeck, R.

1995-08-01

Stationary and time-dependent fluorescence have been measured for a donor/acceptor (DA) pair bound to membrane proteins of bovine erythrocyte ghosts. The donor N-(p-(2-benzoxazolyl)phenyl)-maleimid (BMI) and the acceptor fluram bind to SH- and NH 2 -residues, respectively. The fluorescence spectra and the time-dependent emission are consistent with a radiationless fluorescence energy transfer (RET). The density of RET-effective acceptor binding sites c=0.072 nm -2 was calculated on the basis of the two-dimensional Foerster-kinetic. Band3 protein is the only membrane spanning protein with accessible SH-groups, and therefore only effective binding sites on the band3 protein are counted for the RET measurements performed. (author). 23 refs, 4 figs, 2 tabs

Effect of temperature and pH on the lipid photoperoxidation and the structural state of erythrocyte membranes

International Nuclear Information System (INIS)

Roshchupkin, D.I.; Pelenitsyn, A.B.; Vladimirov, Yu.A.

1978-01-01

The degree of lipid photoperoxidation in erythrocytes (the amount of TBA-active products accumulated under the given dose of ultraviolet irradiation at 254 nm) increased abruptly with temperature in the interval 12 - 20 0 C, then it increased more slowly and later on passed over the maximum at about 30 - 32 0 C. Apparently, the degree of lipid photoperoxidation can serve as a sensitive index of lipid structural state. Using a method of modelling of erythrocyte membranes by liposomes of different chemical content, it was shown that under temperature changes in physiological limits the lipids of erythrocyte membranes undergo at least two structural transformations. The first might be a change in the relative position of cholesterol and phospholipids. The second is followed by the enhancement of membrane antioxidant activity. The degree of lipid photoperoxidation in erythrocytes grows with increasing pH from 6 to 8 according to S-shaped curve with middle point at pH 7.0. This effect can be attributed to structural transformation of membrane lipid zone associated with ionization of membrane protein hystidine. The swelling of erythrocytes in hypotonic medium also leads to structural transformation of lipid zone. (author)

In vitro erythrocytic membrane effects of dibenzyl trisulfide, a secondary metabolite of Petiveria alliacea.

Science.gov (United States)

Pepple, D J; Richards, A A; Lowe, D A; Reid, W A; Younger, N O; Williams, L A D

2010-12-01

We investigated the in vitro effect of dibenzyl trisulfide (DTS), a secondary metabolite of Petiveria alliacea, on erythrocyte elasticity, relaxation time and membrane morphology. Blood samples from 8 volunteers with hemoglobin AA were exposed to 100, 200, 400, 800 and 1000 ng/ml of DTS respectively and the elasticity and relaxation time measured. There were statistically significant, dose-dependent increases in elasticity and relaxation times. The changes in membrane morphology observed also increased with increased concentration of DTS. This suggests that DTS interaction with membrane protein resulted in increased elasticity, relaxation time and deformation of the erythrocyte membrane. Copyright © 2010 Elsevier B.V. All rights reserved.

Interaction of Plasmodium falciparum knob-associated histidine-rich protein (KAHRP) with erythrocyte ankyrin R is required for its attachment to the erythrocyte membrane.

Science.gov (United States)

Weng, Haibo; Guo, Xinhua; Papoin, Julien; Wang, Jie; Coppel, Ross; Mohandas, Narla; An, Xiuli

2014-01-01

The malaria parasite Plasmodium falciparum exports a large number of proteins into the erythrocyte cytoplasm during the asexual intraerythrocytic stage of its life cycle. A subset of these proteins interacts with erythrocyte membrane skeletal proteins and grossly alters the structure and function of the membrane. Several of the exported proteins, such as PfEMP1, PfEMP3, RESA and KAHRP, interact with the preponderant erythrocyte skeleton protein, spectrin. Here we have searched for possible interaction of these four malaria proteins with another major erythrocyte skeleton protein, ankyrin R. We have shown that KAHRP, but none of the other three, binds to ankyrin R. We have mapped the binding site for ankyrin R to a 79-residue segment of the KAHRP sequence, and the reciprocal binding site for KAHRP in ankyrin R to a subdomain (D3) of the 89kDa ankyrin R membrane-binding domain. Interaction of intact ankyrin R with KAHRP was inhibited by the free D3 subdomain. When, moreover, red cells loaded with the soluble D3 subdomain were infected with P. falciparum, KAHRP secreted by the intraerythrocytic parasite no longer migrated to the host cell membrane, but remained diffusely distributed throughout the cytosol. Our findings suggest a potentially important role for interaction of KAHRP with red cell membrane skeleton in promoting the adhesion of malaria-infected red cells to endothelial surfaces, a central element in the pathophysiology of malaria. © 2013.

Influence of high energy electron irradiation and gamma irradiation on the osmotic resistance of human erythrocyte membranes

International Nuclear Information System (INIS)

Catana, D.; Hategan, Alina; Moraru, Rodica; Popescu, Alina; Morariu, V. V.

1998-01-01

The effects of 5 MeV electrons and of gamma irradiation at 0 deg. C on the osmotic fragility of human erythrocyte membranes are presented. Both electron and gamma radiation in the range 0-400 Gy induced no hemolysis indicating that the membrane modifications due to radiation interaction do not reach a critical point as to cause swelling of the cells and subsequent lysis. The osmotic stress experiments performed after irradiation showed that the gamma irradiated erythrocytes exhibited an almost similar sigmoidal behavior for all irradiation doses, whereas the electron irradiated samples showed a much larger increase in hemolysis degree and, in the case of a given electron dose (100 Gy), the hemolysis was found much smaller than for the control sample (a similar behavior of the erythrocytes was found in the case of microwave irradiation at temperatures under 0 deg. C). Our experimental data suggest that electron radiation and gamma radiation have different impacts on the erythrocyte membrane fluidity, involving, probably, the different rate of energy deposition in the samples and the direct interaction of electrons with the erythrocyte membranes. (authors)

Inward cholesterol gradient of the membrane system in P. falciparum-infected erythrocytes involves a dilution effect from parasite-produced lipids

Directory of Open Access Journals (Sweden)

Fuyuki Tokumasu

2014-05-01

Full Text Available Plasmodium falciparum (Pf infection remodels the human erythrocyte with new membrane systems, including a modified host erythrocyte membrane (EM, a parasitophorous vacuole membrane (PVM, a tubulovesicular network (TVN, and Maurer's clefts (MC. Here we report on the relative cholesterol contents of these membranes in parasitized normal (HbAA and hemoglobin S-containing (HbAS, HbAS erythrocytes. Results from fluorescence lifetime imaging microscopy (FLIM experiments with a cholesterol-sensitive fluorophore show that membrane cholesterol levels in parasitized erythrocytes (pRBC decrease inwardly from the EM, to the MC/TVN, to the PVM, and finally to the parasite membrane (PM. Cholesterol depletion of pRBC by methyl-β-cyclodextrin treatment caused a collapse of this gradient. Lipid and cholesterol exchange data suggest that the cholesterol gradient involves a dilution effect from non-sterol lipids produced by the parasite. FLIM signals from the PVM or PM showed little or no difference between parasitized HbAA vs HbS-containing erythrocytes that differed in lipid content, suggesting that malaria parasites may regulate the cholesterol contents of the PVM and PM independently of levels in the host cell membrane. Cholesterol levels may affect raft structures and the membrane trafficking and sorting functions that support Pf survival in HbAA, HbAS and HbSS erythrocytes.

Membrane-bound 2,3-diphosphoglycerate phosphatase of human erythrocytes.

Science.gov (United States)

Schröter, W; Neuvians, M

1970-12-01

Gradual osmotic hemolysis of human erythrocytes reduces the cell content of whole protein, hemoglobin, 2,3-diphosphoglycerate and triosephosphate isomerase extensively, but not that of membrane protein and 2,3-diphosphoglycerate phosphatase. After the refilling of the ghosts with 2,3-diphosphoglycerate and reconstitution of the membrane, the 2,3-diphosphoglycerate phosphatase activity equals that of intact red cells. The membrane-bound 2,3-diphosphoglycerate phosphatase can be activated by sodium hyposulfite. The enzyme system of ghosts seems to differ from that of intact red cells with regard to the optima of pH and temperature. It remains to be elucidated if the membrane binding of the 2,3-diphosphoglycerate phosphatase is related to the transfer of inorganic phosphate across the red cell membrane.

Vitamin E supplementation protects erythrocyte membranes from oxidative stress in healthy Chinese middle-aged and elderly people.

Science.gov (United States)

Sun, Yongye; Ma, Aiguo; Li, Yong; Han, Xiuxia; Wang, Qiuzhen; Liang, Hui

2012-05-01

Elderly people are subject to higher levels of oxidative stress than are young people. Vitamin E, as a powerful antioxidant residing mainly in biomembranes, may provide effective protection against oxidative membrane damage and resultant age-related deterioration, especially in the elderly. We hypothesized that appropriate levels of vitamin E supplementation would protect erythrocyte membranes from oxidative stress and thus improve membrane fluidity in healthy middle-aged and elderly people. To test this, we conducted a 4-month double-blind, randomized trial in which 180 healthy subjects (55-70 years old) were randomly divided into 4 groups: group C (control), and 3 treatment groups in which daily doses of 100 mg (VE1), 200 mg (VE2), and 300 mg (VE3) dl-α-tocopheryl acetate were administered. We measured plasma α-tocopherol concentration, malondialdehyde, and superoxide dismutase levels, erythrocyte hemolysis, and erythrocyte membrane fluidity at the beginning and end of the trial. After 4 months supplementation, plasma α-tocopherol concentrations in the 3 treatment groups had increased by 71%, 78%, and 95%, respectively (all P stress in healthy middle-aged to elderly people, at least in part by improving erythrocyte membrane fluidity and reducing erythrocyte hemolysis. Copyright © 2012 Elsevier Inc. All rights reserved.

Lack of Aquaporin 3 in bovine erythrocyte membranes correlates with low glycerol permeation.

Science.gov (United States)

Campos, Elisa; Moura, Teresa F; Oliva, Abel; Leandro, Paula; Soveral, Graça

2011-05-13

In general, erythrocytes are highly permeable to water, urea and glycerol. However, expression of aquaporin isoforms in erythrocytes appears to be species characteristic. In the present study, human (hRBC) and bovine (bRBC) erythrocytes were chosen for comparative studies due to their significant difference in membrane glycerol permeability. Osmotic water permeability (P(f)) at 23°C was (2.89 ± 0.37) × 10(-2) and (5.12 ± 0.61) × 10(-2)cms(-1) for human and bovine cells, respectively, with similar activation energies for water transport. Glycerol permeability (P(gly)) for human ((1.37 ± 0.26) × 10(-5)cms(-1)) differed in three orders of magnitude from bovine erythrocytes ((5.82 ± 0.37) × 10(-8)cms(-1)) that also showed higher activation energy for glycerol transport. When compared to human, bovine erythrocytes showed a similar expression pattern of AQP1 glycosylated forms on immunoblot analysis, though in slight higher levels, which could be correlated with the 1.5-fold larger P(f) found. However, AQP3 expression was not detectable. Immunofluorescence analysis confirmed the absence of AQP3 expression in bovine erythrocyte membranes. In conclusion, lack of AQP3 in bovine erythrocytes points to the lipid pathway as responsible for glycerol permeation and explains the low glycerol permeability and high E(a) for transport observed in ruminants. Copyright © 2011 Elsevier Inc. All rights reserved.

Erythrocyte membrane fatty acids in multiple sclerosis patients and ...

African Journals Online (AJOL)

The risk of developing multiple sclerosis (MS) is associated with increased dietary intake of saturated fatty acids. For many years it has been suspected that this disease might be associated with an imbalance between unsaturated and saturated fatty acids. We determined erythrocyte membrane fatty acids levels in Hot ...

Electron paramagnetic resonance study of lipid and protein membrane components of erythrocytes oxidized with hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Mendanha, S.A.; Anjos, J.L.V.; Silva, A.H.M.; Alonso, A. [Instituto de Física, Universidade Federal de Goiás, Goiânia, GO (Brazil)

2012-04-05

Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to monitor membrane dynamic changes in erythrocytes subjected to oxidative stress with hydrogen peroxide (H{sub 2}O{sub 2}). The lipid spin label, 5-doxyl stearic acid, responded to dramatic reductions in membrane fluidity, which was correlated with increases in the protein content of the membrane. Membrane rigidity, associated with the binding of hemoglobin (Hb) to the erythrocyte membrane, was also indicated by a spin-labeled maleimide, 5-MSL, covalently bound to the sulfhydryl groups of membrane proteins. At 2% hematocrit, these alterations in membrane occurred at very low concentrations of H{sub 2}O{sub 2} (50 µM) after only 5 min of incubation at 37°C in azide phosphate buffer, pH 7.4. Lipid peroxidation, suggested by oxidative hemolysis and malondialdehyde formation, started at 300 µM H{sub 2}O{sub 2} (for incubation of 3 h), which is a concentration about six times higher than those detected with the probes. Ascorbic acid and α-tocopherol protected the membrane against lipoperoxidation, but did not prevent the binding of proteins to the erythrocyte membrane. Moreover, the antioxidant (+)-catechin, which also failed to prevent the cross-linking of cytoskeletal proteins with Hb, was very effective in protecting erythrocyte ghosts from lipid peroxidation induced by the Fenton reaction. This study also showed that EPR spectroscopy can be useful to assess the molecular dynamics of red blood cell membranes in both the lipid and protein domains and examine oxidation processes in a system that is so vulnerable to oxidation.

Synthesis of erythrocyte membrane proteins in dispersed cells from fetal rat liver

International Nuclear Information System (INIS)

Kitagawa, Yasuo; Murakami, Akihiko; Sugimoto, Etsuro

1984-01-01

Protein synthesis in dispersed cells from fetal liver was studied by fluorography of SDS-polyacrylamide gel electrophoresis of a [ 35 S] methionine labeled cell lysate. Synthesis of several proteins with molecular weights ranging from 45,000 to 220,000 was observed during erythropoiesis in fetal liver. Some of these proteins were demonstrated to be erythrocyte membrane proteins because they were immunoprecipitated with antiserum against rat red blood cells and the immunoprecipitation was competitive with non-radioactive proteins solubilized from erythrocyte ghosts. The same antiserum caused agglutination of dispered cells from fetal liver. This supported the possibility that these proteins are translocated onto plasma membranes of the dispersed cells. (author)

Physicochemical characterization of artificial nanoerythrosomes derived from erythrocyte ghost membranes.

Science.gov (United States)

Deák, Róbert; Mihály, Judith; Szigyártó, Imola Cs; Wacha, András; Lelkes, Gábor; Bóta, Attila

2015-11-01

Colloidal stabile nanoerythrosomes with 200 nm average diameter were formed from hemoglobin-free erythrocyte ghost membrane via sonication and membrane extrusion. The incorporation of extra lipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC), added to the sonicated ghosts, caused significant changes in the thermotropic character of the original membranes. As a result of the increased DPPC ratio the chain melting of the hydrated DPPC system and the characteristic small angle X-ray scattering (SAXS) of the lipid bilayers appeared. Significant morphological changes were followed by transmission electron microscopy combined with freeze fracture method (FF-TEM). After the ultrasonic treatment the large entities of erythrocyte ghosts transformed into nearly spherical nanoerythrosomes with diameters between 100 and 300 nm and at the same time a great number of 10-30 nm large membrane proteins or protein clusters were dispersed in the aqueous medium. The infrared spectroscopy (FT-IR) pointed out, that the sonication did not cause changes in the secondary structures of the membrane proteins under our preparation conditions. About fivefold of extra lipid--compared to the lipid content of the original membrane--caused homogeneous dispersion of nanoerythrosomes however the shape of the vesicles was not uniform. After the addition of about tenfold of DPPC, monoform and monodisperse nanoerythrosomes became typical. The outer surfaces of these roughly spherical objects were frequently polygonal, consisting of a net of pentagons and hexagons. Copyright © 2015 Elsevier B.V. All rights reserved.

Erythrocyte swelling and membrane hole formation in hypotonic media as studied by conductometry.

Science.gov (United States)

Pribush, A; Meyerstein, D; Hatskelzon, L; Kozlov, V; Levi, I; Meyerstein, N

2013-02-01

Hypoosmotic swelling of erythrocytes and the formation of membrane holes were studied by measuring the dc conductance (G). In accordance with the theoretical predictions, these processes are manifested by a decrease in G followed by its increase. Thus, unlike the conventional osmotic fragility test, the proposed methodological approach allows investigations of both the kinetics of swelling and the erythrocyte fragility. It is shown that the initial rate of swelling and the equilibrium size of the cells are affected by the tonicity of a hypotonic solution and the membrane rheological properties. Because the rupture of biological membranes is a stochastic process, a time-dependent increase in the conductance follows an integral distribution function of the membrane lifetime. The main conclusion which stems from reported results is that information about rheological properties of red blood cell (RBC) membranes and the resistivity of RBCs to a certain osmotic shock may be extracted from conductance signals.

In vitro effects of the anti-Alzheimer drug memantine on the human erythrocyte membrane and molecular models

International Nuclear Information System (INIS)

Zambrano, Pablo; Suwalsky, Mario; Villena, Fernando; Jemiola-Rzeminska, Malgorzata; Strzalka, Kazimierz

2017-01-01

Memantine is a NMDA antagonist receptor clinically used for treating Alzheimer's disease. NMDA receptors are present in the human neurons and erythrocyte membranes. The aim of the present study was to investigate the effects of memantine on human erythrocytes. With this purpose, the drug was developed to in vitro interact with human red cells and bilayers built-up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE). The latter represent lipids respectively present in both outer and inner monolayers of the red cell membrane. Results obtained by scanning electron microscopy (SEM) showed that memantine changed the normal biconcave shape of red cells to cup-shaped stomatocytes. According to the bilayer-couple hypothesis the drug intercalated into the inner monolayer of the erythrocyte membrane. Experimental results obtained by X-ray diffraction on multibilayers of DMPC and DMPE, and by differential scanning calorimetry on multilamellar vesicles indicated that memantine preferentially interacted with DMPC in a concentration-dependent manner. Thus, it can be concluded that in the low therapeutic plasma concentration of circa 1 μM memantine is located in NMDA receptor channel without affecting the erythrocyte shape. However, at higher concentrations, once the receptors became saturated excess of memantine molecules (20 μM) would interact with phosphoinositide lipids present in the inner monolayer of the erythrocyte membrane inducing the formation of stomatocytes. However, 40–50 μM memantine was required to interact with isolated phosphatidylcholine bilayers. - Highlights: • The interaction of memantine with human erythrocytes and lipid bilayers were assessed. • Memantine induced morphological changes to human erythrocytes. • Memantine interacted with classes of phospholipids present in the erythrocyte membrane. • Results support the hypothesis that memantine interacts with NMDA receptors.

Erythrocyte membrane stabilization effect and antioxidant activity of methyl methacrylate

International Nuclear Information System (INIS)

Popov, B.

2004-01-01

Methyl methacrylate (MMK) is a synthetic product with mild impact on human health that is not well studied on cellular basis. Here, human erythrocytes were used to investigate the effects MMK exerts on acid and heat-induced hemolysis. Biphasic effect of MMK was observed for acid-induced hemolysis; i.e., protection at low (0 - 0.05% v/v) and stimulation at higher (0.1- 0.4% v/v) concentrations. The maximal protective effect was produced at 0.03% (v/v). At this concentration MMK increased the temperatures of heat denaturation of erythrocyte membrane proteins, spectrin and integral proteins, by about 2 0 C and inhibited the heat-induced hemolysis by 20 %. This membrane stabilization effect of MMK is similar to that produced by some anti-inflammatory and antirheumatic drugs. The increased acid resistance possibly indicated anti-oxidant properties of MMK. The nonenzymatic antioxidant activity test evidenced that MMK has no superoxide dismutase-like activity but demonstrates strong catalase-like activity (about 900 kU/mmol at 0.05-0.1 mmol/l concentration). The results indicate that at low concentration MMK exerts benign effect on cellular membrane that could find therapeutic usage. (author)

Hierarchical, domain type-specific acquisition of antibodies to Plasmodium falciparum erythrocyte membrane protein 1 in Tanzanian children

DEFF Research Database (Denmark)

Cham, Gerald K K; Turner, Louise; Kurtis, Jonathan D

2010-01-01

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of malaria-infected erythrocytes. PfEMP1 attaches to the vascular lining and allows infected erythrocytes to avoid filtration through the spleen. Each parasite genome encodes about 60 diffe...... and play a major role in limiting parasite multiplication in the blood.......Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of malaria-infected erythrocytes. PfEMP1 attaches to the vascular lining and allows infected erythrocytes to avoid filtration through the spleen. Each parasite genome encodes about 60...... different PfEMP1 variants, each PfEMP1 comprises several domains in its extracellular region, and the PfEMP1 repertoire in different parasites contains domain types that are serologically cross-reactive. In this longitudinal study, we followed 672 children living in an area of high malaria transmission...

An in vitro study on the antioxidant capacity of usnic acid on human erythrocytes and molecular models of its membrane.

Science.gov (United States)

Suwalsky, M; Jemiola-Rzeminska, M; Astudillo, C; Gallardo, M J; Staforelli, J P; Villena, F; Strzalka, K

2015-11-01

Usnic acid (UA) has been associated with chronic diseases through its antioxidant action. Its main target is the cell membrane; however, its effect on that of human erythrocytes has been scarcely investigated. To gain insight into the molecular mechanisms of the interaction between UA and cell membranes human erythrocytes and molecular models of its membrane have been utilized. Dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were chosen as representative of phospholipid classes located in the outer and inner monolayers of the erythrocyte membrane, respectively. Results by X-ray diffraction showed that UA produced structural perturbations on DMPC and DMPE bilayers. DSC studies have indicated that thermotropic behavior of DMPE was most strongly distorted by UA than DMPC, whereas the latter is mainly affected on the pretransition. Scanning electron (SEM) and defocusing microscopy (DM) showed that UA induced alterations to erythrocytes from the normal discoid shape to echinocytes. These results imply that UA molecules were located in the outer monolayer of the erythrocyte membrane. Results of its antioxidant properties showed that UA neutralized the oxidative capacity of HClO on DMPC and DMPE bilayers; SEM, DM and hemolysis assays demonstrated the protective effect of UA against the deleterious oxidant effects of HClO upon human erythrocytes. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiation damages to cell membranes of dogs and rats quantitatively estimated by changes in sedimentation behaviour of erythrocytes

International Nuclear Information System (INIS)

Mikhajlov, V.F.; Potemkin, L.A.

1985-01-01

It was shown that injury to plasma membranes leads to a change in the sedimentation behaviour of erythrocytes: the maximum effect is produced when a protein component of the membrane is affected. The same dose dependent character of the change in erythrocyte sedimentation in urografine are observed during the first 24 h after γ-irradiation of rats and dogs

Association between vascular calcification scores on plain radiographs and fatty acid contents of erythrocyte membrane in hemodialysis patients.

Science.gov (United States)

Son, Young K; Lee, Su M; Kim, Seong E; Kim, Ki H; Lee, Seon Y; Bae, Hae R; Han, Jin Y; Park, Yongsoon; An, Won S

2012-01-01

Vascular calcification (VC) scores determined by using simple plain radiographic films are known to be associated with coronary artery disease and mortality in patients undergoing hemodialysis (HD). Omega-3 fatty acid (FA) has been shown to reduce ectopic calcifications in an animal model, and it has also been shown that erythrocyte membrane omega-3 FA content is an independent discriminator of coronary artery disease. The present study was designed to demonstrate relations between VC scores and erythrocyte membrane FA contents in patients undergoing HD. A cross-sectional study was carried out. The study was carried out at an outpatient hemodialysis unit at Dong-A University Hospital, Busan, Republic of Korea. A total of 31 patients undergoing HD were recruited. Patients with significant malnutrition, a short duration of dialysis (acid and docosahexaenoic acid were not found to be related with VC on simple plain radiographic films. However, erythrocyte membrane contents of oleic acid and total monounsaturated FA (MUFA) were significantly higher in patients with significant VC scores. Furthermore, erythrocyte membrane contents of MUFA and oleic acid were found to be negatively associated with high-density lipoprotein cholesterol level and positively associated with triglyceride level. Erythrocyte membrane contents of MUFA and oleic acid were found to be associated with VC scores determined using plain radiographs and with dyslipidemia in patients undergoing HD. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

[Peculiarities of the phospholipid and fatty acid composition of erythrocyte plasma membranes of the Black Sea fish].

Science.gov (United States)

Silkin, Iu A; Silkina, E N; Zabelinskiĭ, S A

2012-01-01

The phospholipid and the fatty acid composition of the main phospholipids families of erythrocyte plasma membranes was studied in two species of cartilaginous fish: the common thrasher (Raja clavata L.) and the common stingray (Dasyatis pastinaca) and three bony fish species: the scorpion fish (Scorpaena porcus L.), the smarida (Spicara flexuosa Raf.), and the horse mackerel (Trachurus mediterraneus ponticus Aleev). It was shown that in the studied fish, 70.0-80.0 % of all membrane phospholipids were composed of phosphatidylcholine and phosphatidylethanolamine. Phosphatidylserine, monophosphoinositide, and sphingomyelin were minor components whose content in the erythrocyte membrane fluctuated from 3.0 % to 13.0 %. The fatty acid phospholipids composition was represented by a large specter of acids. From saturated acids, basic for plasma membranes are palmitic (C16: 0) and stearic (C18: 0) acids. From unsaturated acids, the larger part belong to mono-, tetra-, penta-, and hexaenoic acids in fish phospholipids. The calculation of the double bond index and of the unsaturation coefficient showed difference in the deformation ability of erythrocyte membranes of the studied fish.

 Oxidative stress modulates the organization of erythrocyte membrane cytoskeleton

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Maria Olszewska

2012-07-01

Full Text Available  Background:Apart from their main role in transporting oxygen and carbon dioxide, erythrocytes play also an important role in organism antioxidative defence. Direct exposure to reactive oxygen species (ROS results in shortening of their half-life, even by 50�20The presence of glucose, being the substrate in pentose phosphate pathway (PPP cycle, is one of the factors that can have influence on the level of oxidative stress. The activity of PPP increases during oxidative stress. Glucose guarantees normal PPP functioning with the production of reductive equivalents in the amounts necessary to reproduction of glutathione – nonenzymatic free radical scavenger. In available literature there are no reports regarding the changes in protein contents of erythrocyte cytoskeleton exposed to t-butyl hydroperoxide in relation to glucose presence in incubation medium.Material/methods:Erythrocytes taken from 10 healthy subjects were used to assess the influence of generated free radicals on erythrocyte proteins and chosen parameters of oxidative stress. Erythrocytes were incubated in the solutions containing deferent concentrations of t-butyl hydroperoxide and glucose. Electrophoresis was performed on polyacrylamide gel in denaturating conditions. The contents of tryptophan in membranes was evaluated spectrofluorometrically.Results/conclusions:In vitro conditions oxidative stress leads to protein damage in erythrocyte cytoskeleton, both in proteins inside the cell as well as having contact with extracellular environment. In consequence, the amount of low-molecular proteins – mainly globin, which bind to cytoskeleton, increases. This process takes place independently of glucose presence in incubation medium. One of the element of protein cytoskeleton, tryptophan, also undergoes degradation. The decrease of its contents is higher during erythrocyte exposure to t-BOOH in environment containing glucose, what can suggest prooxidative influence of glucose in

Effects of Iron Overload on the Activity of Na,K-ATPase and Lipid Profile of the Human Erythrocyte Membrane.

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Leilismara Sousa

Full Text Available Iron is an essential chemical element for human life. However, in some pathological conditions, such as hereditary hemochromatosis type 1 (HH1, iron overload induces the production of reactive oxygen species that may lead to lipid peroxidation and a change in the plasma-membrane lipid profile. In this study, we investigated whether iron overload interferes with the Na,K-ATPase activity of the plasma membrane by studying erythrocytes that were obtained from the whole blood of patients suffering from iron overload. Additionally, we treated erythrocytes of normal subjects with 0.8 mM H2O2 and 1 μM FeCl3 for 24 h. We then analyzed the lipid profile, lipid peroxidation and Na,K-ATPase activity of plasma membranes derived from these cells. Iron overload was more frequent in men (87.5% than in women and was associated with an increase (446% in lipid peroxidation, as indicated by the amount of the thiobarbituric acid reactive substances (TBARS and an increase (327% in the Na,K-ATPase activity in the plasma membrane of erythrocytes. Erythrocytes treated with 1 μM FeCl3 for 24 h showed an increase (132% in the Na,K-ATPase activity but no change in the TBARS levels. Iron treatment also decreased the cholesterol and phospholipid content of the erythrocyte membranes and similar decreases were observed in iron overload patients. In contrast, erythrocytes treated with 0.8 mM H2O2 for 24 h showed no change in the measured parameters. These results indicate that erythrocytes from patients with iron overload exhibit higher Na,K-ATPase activity compared with normal subjects and that this effect is specifically associated with altered iron levels.

Grape extract protects against γ-radiation-induced membrane damage strains of human erythrocytes

International Nuclear Information System (INIS)

Das, Subir Kumar

2017-01-01

The membrane integrity of circulating red blood cells (RBCs) is compromised by the deleterious actions of γ-radiation in humans. Grapes are the richest source of antioxidants due to presence of potentially bioactive phytochemicals. The objective of the present study was to assess the radioprotective actions of grape extracts against the γ-radiation-induced membrane permeability of human erythrocytes. The scavenging activities in seeds of grape in DPPH, hydrogen peroxide and hydroxyl radicals, were higher than skin or pulp of different cultivars. Grape extracts also showed appreciable extent of total antioxidant capacity and effective antihemolytic action. Grape extracts significantly ameliorated the γ-radiation-induced increase of the levels of thiobarbituric acid-reactive substances (TBARS, an index of lipid peroxidation) in the RBC membrane ghosts. Stored blood showed higher levels of K + ion as compared to the normal blood which was elevated by γ-radiation. Membrane ATPase was inhibited by the exposure to γ-radiation.Treatment of RBCs with the grape extracts prior to the exposure of γ-radiation significantly mitigated these changes in the erythrocyte membranes caused by the lower dose of radiation (4 Gy). (author)

Band 3 tyrosine kinase in avian erythrocyte plasma membrane is immunologically related to pp60c-src

International Nuclear Information System (INIS)

Hillsgrove, D.; Shores, C.G.; Parker, J.C.; Maness, P.F.

1987-01-01

The authors have identified in the plasma membrane of the chicken erythrocyte a 60-kDa tyrosine-specific protein kinase immunologically related to the transforming protein pp60 v-src of Rous sarcoma virus. The erythrocyte protein kinase phosphorylated heavy chains of tumor-bearing rabbit (TBR) antibodies reactive with pp60 c-src at tyrosine in immune complex protein kinase assays. The kinase was identified as a 60-kDa protein by [ 35 S]methionine labeling of erythrocytes and by autophosphorylation in immune complexes. The kinase migrated on two-dimensional gel electrophoresis with an apparent pI and molecular mass similar to pp60 c-src . A plasma membrane-enriched fraction isolated from chicken red cells contained the majority of the kinase activity. Incubation of the plasma membrane fraction with [ 32 P]ATP resulted in tyrosine phosphorylation of the anion transport protein band 3. Band 3 phosphorylation was blocked by TBR antibodies, indicting that the kinase recognized by pp60 c-src antibodies was responsible for band 3 phosphorylation. These results demonstrate that the avian erythrocyte plasma membrane contains a tightly bound tyrosine-specific protein kinase identical or closely related to pp60 c-src and that this kinase is responsible for band 3 phosphorylation in vitro

Quantitative changes of main components of erythrocyte membranes which define architectonics of cells under pttg gene knockout

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О. P. Kanyuka

2014-04-01

Full Text Available A pttg gene knockout affects the functional state of erythron in mice which could be associated with structural changes in the structure of erythrocyte membranes. The pttg gene knockout causes a significant modification of fatty acids composition of erythrocyte membrane lipids by reducing the content of palmitic acid and increasing of polyunsaturated fatty acids amount by 18%. Analyzing the erythrocyte surface architectonics of mice under pttg gene knockout, it was found that on the background of reduction of the functionally complete biconcave discs population one could observe an increase of the number of transformed cells at different degeneration stages. Researches have shown that in mice with a pttg gene knockout compared with a control group of animals cytoskeletal protein – β-spectrin was reduced by 17.03%. However, there is a reduction of membrane protein band 3 by 33.04%, simultaneously the content of anion transport protein band 4.5 increases by 35.2% and protein band 4.2 by 32.1%. The lectin blot analysis has helped to reveal changes in the structure of the carbohydrate determinants of ery­throcyte membrane glycoproteins under conditions of directed pttg gene inactivation, accompanied by changes in the type of communication, which joins the terminal residue in carbohydrate determinant of glycoproteins. Thus, a significant redistribution of protein and fatty acids contents in erythrocyte membranes that manifested in the increase of the deformed shape of red blood cells is observed under pttg gene knockout.

Quantitative analysis of the erythrocyte membrane proteins in polycythemia vera patients treated with hydroxycarbamide

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Darshana Kottahachchi

2015-06-01

Full Text Available More than 90% of polycythemia vera (PV patients have a mutation in the protein JAK2, which is closely associated with the erythrocyte membrane. With the comparison of 1-D gels of erythrocyte membranes obtained from PV patients treated with hydroxycarbamide and those of untreated controls we observed significant differences in the region of 40–55 kDa. On the basis of the LC–MS/MS analysis of this region we report up-regulation of four protein disulfide isomerases, which was subsequently confirmed by targeted mass spectrometric analysis. In further studies it will be prudent to compare this in patients both treated and not treated with hydroxycarbamide.

Mediterranean-style diet effect on the structural properties of the erythrocyte cell membrane of hypertensive patients: the Prevencion con Dieta Mediterranea Study.

Science.gov (United States)

Barceló, Francisca; Perona, Javier S; Prades, Jesús; Funari, Sérgio S; Gomez-Gracia, Enrique; Conde, Manuel; Estruch, Ramon; Ruiz-Gutiérrez, Valentina

2009-11-01

A currently ongoing randomized trial has revealed that the Mediterranean diet, rich in virgin olive oil or nuts, reduces systolic blood pressure in high-risk cardiovascular patients. Here, we present a structural substudy to assess the effect of a Mediterranean-style diet supplemented with nuts or virgin olive oil on erythrocyte membrane properties in 36 hypertensive participants after 1 year of intervention. Erythrocyte membrane lipid composition, structural properties of reconstituted erythrocyte membranes, and serum concentrations of inflammatory markers are reported. After the intervention, the membrane cholesterol content decreased, whereas that of phospholipids increased in all of the dietary groups; the diminishing cholesterol:phospholipid ratio could be associated with an increase in the membrane fluidity. Moreover, reconstituted membranes from the nuts and virgin olive oil groups showed a higher propensity to form a nonlamellar inverted hexagonal phase structure that was related to an increase in phosphatidylethanolamine lipid class. These data suggest that the Mediterranean-style diet affects the lipid metabolism that is altered in hypertensive patients, influencing the structural membrane properties. The erythrocyte membrane modulation described provides insight in the structural bases underlying the beneficial effect of a Mediterranean-style diet in hypertensive subjects.

A robust mass spectrometry method for rapid profiling of erythrocyte ghost membrane proteomes.

Science.gov (United States)

Fye, Haddy K S; Mrosso, Paul; Bruce, Lesley; Thézénas, Marie-Laëtitia; Davis, Simon; Fischer, Roman; Rwegasira, Gration L; Makani, Julie; Kessler, Benedikt M

2018-01-01

Red blood cell (RBC) physiology is directly linked to many human disorders associated with low tissue oxygen levels or anemia including chronic obstructive pulmonary disease, congenital heart disease, sleep apnea and sickle cell anemia. Parasites such as Plasmodium spp. and phylum Apicomplexa directly target RBCs, and surface molecules within the RBC membrane are critical for pathogen interactions. Proteomics of RBC membrane 'ghost' fractions has therefore been of considerable interest, but protocols described to date are either suboptimal or too extensive to be applicable to a larger set of clinical cohorts. Here, we describe an optimised erythrocyte isolation protocol from blood, tested for various storage conditions and explored using different fractionation conditions for isolating ghost RBC membranes. Liquid chromatography mass spectrometry (LC-MS) analysis on a Q-Exactive Orbitrap instrument was used to profile proteins isolated from the comparative conditions. Data analysis was run on the MASCOT and MaxQuant platforms to assess their scope and diversity. The results obtained demonstrate a robust method for membrane enrichment enabling consistent MS based characterisation of > 900 RBC membrane proteins in single LC-MS/MS analyses. Non-detergent based membrane solubilisation methods using the tissue and supernatant fractions of isolated ghost membranes are shown to offer effective haemoglobin removal as well as diverse recovery including erythrocyte membrane proteins of high and low abundance. The methods described in this manuscript propose a medium to high throughput framework for membrane proteome profiling by LC-MS of potential applicability to larger clinical cohorts in a variety of disease contexts.

Sequential, ordered acquisition of antibodies to Plasmodium falciparum erythrocyte membrane protein 1 domains

DEFF Research Database (Denmark)

Cham, Gerald K K; Turner, Louise; Lusingu, John

2009-01-01

The binding of erythrocytes infected with mature blood stage parasites to the vascular bed is key to the pathogenesis of malignant malaria. The binding is mediated by members of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family. PfEMP1s can be divided into groups, and it has pr....... The identification of PfEMP1 domains expressed by parasites causing disease in infants and young children is important for development of vaccines protecting against severe malaria.......The binding of erythrocytes infected with mature blood stage parasites to the vascular bed is key to the pathogenesis of malignant malaria. The binding is mediated by members of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family. PfEMP1s can be divided into groups, and it has...... previously been suggested that parasites expressing group A or B/A PfEMP1s are most pathogenic. To test the hypothesis that the first malaria infections in infants and young children are dominated by parasites expressing A and B/A PfEMP1s, we measured the plasma Ab level against 48 recombinant PfEMP1 domains...

Characterization of changes in composition and function of erythrocyte membrane proteins in patients with bone marrow form of acute radiation sickness

International Nuclear Information System (INIS)

Li Jinying; Wei Shanjian; Hu Xiaojian

1998-01-01

Objective: The delayed effect of radiation on erythrocyte membrane protein, the composition and function of the membrane proteins in five patients with bone marrow form of acute radiation sickness (ARS) were follow up at six years after the Shanghai 60 Co irradiation accident. Methods: Percoll centrifugation, SDS-polyacrylamide gel electrophoresis, and analysis of NO 2 - transport rate and DIDS inhibition rate were performed. Results: The injuries of the membrane proteins induced by radiation, characterized by reduced content of band 8 and declined anion transport function of band 3 protein remained the same as initially observed. The further study showed that the inhibition of DIDS on the anion transport of the ARS erythrocytes was decreased and the transport time for NO 2 - by band 3 was significantly prolonged in younger erythrocytes than those in middle-or old-aged cells. Conclusion: It is suggested that the radiation damage to erythrocyte membrane proteins might occur at the stage of erythropoiesis in bone marrow. The exo-facial site in band 3 may be changed after radiation, which could result in the abnormalities in anion transport. It is believed that the aging of erythrocytes might be present in advanced stage of ARS

Erythrocyte membrane fatty acids in benign and progressive forms of multiple sclerosis

NARCIS (Netherlands)

Koch, M; Ramsaransing, GSM; Fokkema, MR; Heersema, DJ; De Keyser, J

2006-01-01

BACKGROUND: There is no good explanation why a proportion of patients with multiple sclerosis (MS) have a relatively benign form of the disease. An imbalance between saturated and unsaturated fatty acids (FA) might influence the disease course of MS. AIM: To assess whether the erythrocyte membrane

Effect of Omega-3 Fatty Acids on Erythrocyte Membrane in Diabetic Rats

OpenAIRE

Hussein, Jihan; Mostafa, Ehab; El-Waseef, Maha; El-Khayat, Zakarya; Badawy, Ehsan; Medhat, Dalia

2011-01-01

Background: Diabetes mellitus is a metabolic disease characterized by chronic hyperglycemia resulting from defects in insulin secretion, almost always with a major contribution from insulin resistance which may be affected by cell membrane fatty acids and phospholipids fractions.Aim: To evaluate the effects of omega-3 fatty acids on erythrocyte membrane and also in decreasing oxidative stress in diabetic rats.Material and Methods: Sixty healthy male albino rats weighting 180-200 g divided int...

The lateral distribution of intramembrane particles in the erythrocyte membrane and recombinant vesicles

NARCIS (Netherlands)

Gerritsen, A.; Verkleij, A.J.; Deenen, L.L.M. van

1979-01-01

Triton X-100 (in concentrations which did not cause a significant solubilization of membrane material) caused aggregation of the intramembrane particles of human erythrocyte ghosts. Ghosts from which the extrinsic proteins had been removed by alkali treatment showed a temperature-induced

Biophysical parameters of erythrocyte membranes and mechanisms of interaction with non-opioid analgesics under acute pain syndrome

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Yu. I. Gubskyi

2014-06-01

Full Text Available Methods of fluorescent probing, spectrophotometry and microcalorimetry were applied to investigate the alterations in biophysical parameters of erythrocytes membranes, and specifically microviscosity, surface charge, molecular organization of lipid bilayer and lipid-protein interactions under conditions of acute pain syndrome produced by experimental chemical lesion. The distinctive features of non-opiod analgesics interactions and binding to the erythrocytes membranes of rats subjected to acute nociceptive pain accompanied with oxidative stress development were investigated. The abilities of analgesics under research, and namely paracetamol, aspirin, phenazone, ketorolac, pyrodazole, ketoprofenum, natrium mefenaminate, indometacin, nimesulide to make up physico-chemical complexes with lipoperoxidation modified erythrocytes surface and protein-lipid bilayer showed marked changes. The significance of oxidative damage of biophase under conditions of acute pain syndrome for analgesics effective pharmacodynamics and pharmacokinetics realization is under consideration.

Modulation of Erythrocyte Plasma Membrane Redox System Activity by Curcumin

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Prabhakar Singh

2016-01-01

Full Text Available Plasma membrane redox system (PMRS is an electron transport chain system ubiquitously present throughout all cell types. It transfers electron from intracellular substrates to extracellular acceptors for regulation of redox status. Curcumin, isolated from Curcuma longa, has modulatory effects on cellular physiology due to its membrane interaction ability and antioxidant potential. The present study investigates the effect of curcumin on PMRS activity of erythrocytes isolated from Wistar rats in vitro and in vivo and validated through an in silico docking simulation study using Molegro Virtual Docker (MVD. Effects of curcumin were also evaluated on level of glutathione (GSH and the oxidant potential of plasma measured in terms of plasma ferric equivalent oxidative potentials (PFEOP. Results show that curcumin significantly (p<0.01 downregulated the PMRS activity in a dose-dependent manner. Molecular docking results suggest that curcumin interacts with amino acids at the active site cavity of cytochrome b5 reductase, a key constituent of PMRS. Curcumin also increased the GSH level in erythrocytes and plasma while simultaneously decreasing the oxidant potential (PFEOP of plasma. Altered PMRS activity and redox status are associated with the pathophysiology of several health complications including aging and diabetes; hence, the above finding may explain part of the role of curcumin in health beneficial effects.

The influence of erythrocyte maturity on ion transport and membrane lipid composition in the rat

Czech Academy of Sciences Publication Activity Database

Vokurková, Martina; Rauchová, Hana; Dobešová, Zdenka; Loukotová, Jana; Nováková, O.; Kuneš, Jaroslav; Zicha, Josef

2016-01-01

Roč. 65, č. 1 (2016), s. 91-99 ISSN 0862-8408 R&D Projects: GA MZd(CZ) NV15-25396A; GA ČR(CZ) GAP304/12/0259 Institutional support: RVO:67985823 Keywords : reticulocytes * immature erythrocytes * mean cellular hemoglobin content * membrane phospholipids * membrane cholesterol Subject RIV: ED - Physiology Impact factor: 1.461, year: 2016

Covalent glycoinositolphospholipid (GPI binding to hemoglobin is associated with insulin-activation of erythrocyte membrane protease

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VESNA NIKETIC

2004-05-01

Full Text Available Recently, it was demonstrated that prolonged hyperinsulinism associated with hypoglycemia, both in vivo and in vitro, caused covalent glycoinositolphospholipid (GPI binding to the C termini of both hemoglobin b-chains, which resulted in the formation of a novel, hitherto unrecognized, minor hemoglobin fraction (GPI-Hb (Niketic et al., Biochem. Biophys. Res. Commun. 239 (1997 435. In this study it was demonstrated that exposure of erythrocyte membranes to insulin causes the activation of membrane protease as well as that the formation of GPI-Hb parallels its activity. It is suggested that the insulin-activated protease is able to catalyze, albeit slowly, the transpeptidation, i.e., the replacement of the carboxy-terminal amino acid(s residues of the Hb b-chains with GPI as an exogenous nucleophile. To our knowledge the present results show for the first time that insulin stimulates protease activity in erythrocyte membranes, as well as that insulin-activated protease may be involved in post-translational GPI binding to proteins.

Effect of some radiosensitising drugs on human erythrocyte membrane - - spin label study

Energy Technology Data Exchange (ETDEWEB)

Mishra, K P [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

1982-02-01

Electron spin resonance and spin label techniques have been employed to study the effects of local anaesthetic drugs, procaine and tetracaine, on human erythrocyte membrane. Both the drugs altered the protein and lipid arrangements in the membrane and these changes were reversible. Procaine had greater effect on the labels attached to proteins while tetracaine fluidized interior of lipid bilayer to a greater extent. The differential effects of these drugs on the protein and lipid labels have been interpreted in terms of their relative penetrability in the membrane. Present results have explained that radiation induced enhanced killing of cells in the presence of these drugs might be due to the alterations in membrane, particularly proteins both structural and enzymatic. In addition, these results indicate a possible relationship between drug-induced structural changes in membrane and their anaesthetic potency.

Effect of gamma radiation on the transport of spin-labeled compounds across the erythrocyte membrane

International Nuclear Information System (INIS)

Gwozdzinski, K.; Bartosz, G.; Leyko, W.

1981-01-01

The effect of ionizing radiation on the non-electrolyte, anion and cation permeability of the erythrocyte membrane was studied by measurement of the reduction rate of appropriate nitroxyl derivatives. Irradiation of bovine erythrocytes in the dose-range of 2-50 krad resulted in a regular dose-dependent increase in the reduction rates of a cation (TEMPO-choline) and a hydrophobic non-electrolyte (TEMPO), and non-regular changes in the reduction rate of a hydrophilic non-electrolyte (TEMPOL). The permeation constant for TEMPO-choline also showed a non-regular response to radiation, similar to the response pattern of other red blood cell parameters. These results also demonstrate that the effects of radiation on the transport of various solutes can be used as a means of distinguishing between different channels of membrane transport. (orig.)

[Impact of oxygen toxic action on the erythrocyte membrane and possibility of estimating central nervous system function disturbances].

Science.gov (United States)

Belić, Branislava; Cincović, Marko R

2011-07-01

BACKGROUND/AIM; Prolonged exposure to hyperbaric oxygen leads to changes of erythrocytes shape as a consequence of toxic effects of oxygen on the erythrocyte membrane. The aim of this study was to examine the association between occurance of pathological forms of erythrocytes at different time from the start of hyperbaric oxygenation and the moment of convulsions occurrence, an interrelationship of different pathological forms of erythrocytes during exposure to hyperbaric oxygenation, as well as the correlation between the presence of ruptured erythrocytes and function of central nervous system (CNS) after completion of hyperbaric treatment. Sixty laboratory mice, Mus musculus, were exposed to the wholly-oxygen pressure of 3.5 absolute atmospheres (ATA). Blood was collected at the 32nd, 34th, 36th, 38th and 40th minutes after the exposure to oxygen. Pathological forms of erythrocytes were examined by electron microscopy. A moment of convulsions occurrence was registered in all animals. After decompression neurological examinations of experimental animals were perfomed. The Pearson's coefficient of correlation, and linear regression equations for the parameters outlined in the aim of the study were calculated. Hyperbaric oxygen caused damages of erythrocytes at the 34th minute after beginning of the treatment. Various forms of abnormal red blood cells occured, and immediately before the occurrence of irreversible changes (erythrocyte membrane rupture) echinocyte shape was dominated. A significant correlation between the number of damaged red blood cells at 34th minute and their number at the 36th, 38th and 40th minute was found. Convulsions were diagnosed significantly earlier in mice with a greater number of damaged red blood cells (p potential burden of CNS after cessation of hyperbaric oxygenation.

NMR studies of human blood cells in health and disease. I. Alterations of the plasma membrane water permeability of erythrocytes

International Nuclear Information System (INIS)

Katona, Eva; Doaga, I. O.; Radulet, Diana; Caplanusi, A.; Negreanu, Cezarina; Mihele, Denisa

1999-01-01

Alterations in pathological cases of the human erythrocyte membrane water permeability were investigated by using a Mn 2+ -doping 1 H nuclear magnetic resonance (NMR) technique. The temperature dependence of the apparent water diffusional exchange through erythrocyte membranes in chronic hepatitis, diabetes, dyslipidemia and essential hypertension was measured and compared to healthy controls. Using moderate manganese concentrations (9-18 mM) and Carr-Purcell-Meiboom-Gill pulse sequences with a large number of refocusing π pulses and short interpulse delay (100 μs) our values of the water exchange times (τ e ) across erythrocyte membranes, obtained within a 10 min time period following the moment of doping, were independent of the actual manganese concentration and the Arrhenius plot for water exchange was linear over the range of 22-42 deg C. A marked increase of the water exchange times values was observed in all studied disease states. In case of chronic hepatitis, diabetes and dyslipidemia the changes observed in transmembrane water exchange time were associated with significant increase in the apparent activation energy of the diffusional water permeability thus, pointing out alterations in the function of the erythrocyte water channel. (author)

NMR studies of human blood cells in health and disease. I. Alterations of the plasma membrane water permeability of erythrocytes

Energy Technology Data Exchange (ETDEWEB)

Katona, Eva; Doaga, I O; Radulet, Diana [Department of Biophysics, Carol Davila University of Medicine and Pharmaceutics, 8 Blvd. Eroilor Sanitari, POB 15-205, RO-76241 Bucharest (Romania); Caplanusi, A [Medical Biochemistry Department, Carol Davila University of Medicine and Pharmaceutics, 8 Blvd. Eroilor Sanitari, POB 15-205, RO-76241 Bucharest (Romania); Negreanu, Cezarina [Division of New Energy Conversion Methods, Institute of Research and Design for Thermoenergetic Equipment, ICPET-CERCETARE, Bucharest (Romania); Mihele, Denisa [Clinical Laboratory Department, Carol Davila University of Medicine and Pharmaceutics, 8 Blvd. Eroilor Sanitari, POB 15-205, RO-76241 Bucharest (Romania)

1999-07-01

Alterations in pathological cases of the human erythrocyte membrane water permeability were investigated by using a Mn{sup 2+}-doping {sup 1}H nuclear magnetic resonance (NMR) technique. The temperature dependence of the apparent water diffusional exchange through erythrocyte membranes in chronic hepatitis, diabetes, dyslipidemia and essential hypertension was measured and compared to healthy controls. Using moderate manganese concentrations (9-18 mM) and Carr-Purcell-Meiboom-Gill pulse sequences with a large number of refocusing {pi} pulses and short interpulse delay (100 {mu}s) our values of the water exchange times ({tau}{sub e}) across erythrocyte membranes, obtained within a 10 min time period following the moment of doping, were independent of the actual manganese concentration and the Arrhenius plot for water exchange was linear over the range of 22-42 deg C. A marked increase of the water exchange times values was observed in all studied disease states. In case of chronic hepatitis, diabetes and dyslipidemia the changes observed in transmembrane water exchange time were associated with significant increase in the apparent activation energy of the diffusional water permeability thus, pointing out alterations in the function of the erythrocyte water channel. (author)

A protein anomaly in erythrocyte membranes of patients with Duchenne muscular dystrophy

Science.gov (United States)

1983-01-01

Raman spectroscopic comparisons of erythrocyte membranes from 20 patients with Duchenne muscular dystrophy and 8 age-matched controls indicate a prominent and consistent protein anomaly in the patient samples. This was apparent in the following: (a) CH-stretching signals from control membranes reveal a thermotropic transition at 15.6 degrees C, attributable to a protein/lipid phase that is lacking in dystrophic membranes. (b) CH-stretching signals from control membranes also show a protein transition at 39 degrees C [pH 7.4] that is shifted to 45 degrees in dystrophic membranes. (c) A reduction in pH to 5.7 shifts this transition from 39 degrees C to 7 degrees C in normal membranes and from 45 degrees C to 24 degrees C in dystrophic membranes. (d) The Amide I/Amide III regions indicate a significant proportion of beta- structured peptide in dystrophic but not normal membranes. (e) Analysis of tyrosine signals indicates greater polar exposure of tyrosine hydroxyl groups in dystrophic vs normal membranes. All of the differences between dystrophic and normal membranes are highly significant (P less than 0.001). PMID:6854213

Influence of the use of statin on the stability of erythrocyte membranes in multiple sclerosis.

Science.gov (United States)

de Freitas, Mariana Vaini; de Oliveira, Marcela Ramos; dos Santos, Diogo Fernandes; de Cássia Mascarenhas Netto, Rita; Fenelon, Sheila Bernardino; Penha-Silva, Nilson

2010-02-01

Multiple sclerosis (MS) probably occurs by oxidative, inflammatory and autoimmune mechanisms. This study investigated the influence of statin on the stability of erythrocyte membranes in MS patients. The population was composed of one group with simvastatin therapy (20 mg/day), another group without statin therapy and a healthy control group. The stability of erythrocytes was evaluated by the half-transition points, H(50) and D(50), obtained from the curves of hemolysis induced by hypotonic shock and ethanol action, respectively. Erythrocytes of MS patients were less stable against lysis by both chaotropes. This behavior may be merely a consequence of the lifestyle of MS patients or it may be intrinsically associated with the conjunct of factors responsible for the development of the disease. The use of statin by MS patients was associated with lower levels of LDL and total cholesterol, as expected, and with higher stability of erythrocytes against ethanol compared to the values of untreated MS patients.

Cytoadhesion to gC1qR through Plasmodium falciparum erythrocyte membrane protein 1 in severe malaria

DEFF Research Database (Denmark)

Magallón-Tejada, Ariel; Machevo, Sónia; Cisteró, Pau

2016-01-01

Cytoadhesion of Plasmodium falciparum infected erythrocytes to gC1qR has been associated with severe malaria, but the parasite ligand involved is currently unknown. To assess if binding to gC1qR is mediated through the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family, we analyzed...

Erythrocyte remodeling in Plasmodium berghei infection: the contribution of SEP family members.

Science.gov (United States)

Currà, Chiara; Pace, Tomasino; Franke-Fayard, Blandine M D; Picci, Leonardo; Bertuccini, Lucia; Ponzi, Marta

2012-03-01

The malaria parasite Plasmodium largely modifies the infected erythrocyte through the export of proteins to multiple sites within the host cell. This remodeling is crucial for pathology and translocation of virulence factors to the erythrocyte surface. In this study, we investigated localization and export of small exported proteins/early transcribed membrane proteins (SEP/ETRAMPs), conserved within Plasmodium genus. This protein family is characterized by a predicted signal peptide, a short lysine-rich stretch, an internal transmembrane domain and a highly charged C-terminal region of variable length. We show here that members of the rodent Plasmodium berghei family are components of the parasitophorous vacuole membrane (PVM), which surrounds the parasite throughout the erythrocytic cycle. During P. berghei development, vesicle-like structures containing these proteins detach from the PVM en route to the host cytosol. These SEP-containing vesicles remain associated with the infected erythrocyte ghosts most probably anchored to the membrane skeleton. Transgenic lines expressing the green fluorescent protein appended to different portions of sep-coding region allowed us to define motifs required for protein export. The highly charged terminal region appears to be involved in protein-protein interactions. © 2011 John Wiley & Sons A/S.

Correlations of the glycemic variability with oxidative stress and erythrocytes membrane stability in patients with type 1 diabetes under intensive treatment.

Science.gov (United States)

Rodrigues, Ricardo; Alves de Medeiros, Luciana; Moreira Cunha, Lucas; da Silva Garrote-Filho, Mario; Bernardino Neto, Morun; Tannus Jorge, Paulo; Santos Resende, Elmiro; Penha-Silva, Nilson

2018-02-07

This study aimed to evaluate the correlations of glycemic variability with erythrocyte membrane stability parameters and oxidative stress markers in patients with DM1 under intensive treatment. 90 patients with DM1 and under intensive treatment of the disease were evaluated in relation to anthropometric indices, records of glycemic averages and parameters of glycemic variability, biochemical dosages (glucose, uric acid, lipidogram, glycated hemoglobin, microalbuminuria, creatinine and iron) reticulocyte count, erythrocyte membrane stability parameters and oxidative stress markers (thiobarbituric acid reactive substances, TBARS, and glutathione reductase, GR). Indicators of glycemic variability in the short and long term showed correlations with parameters of membrane stability and markers of oxidative stress (GR). In addition, the comparison of these same parameters between the subgroups consisting of quartiles of GV or glycemic control also showed significant differences. In the DM1 patients studied here, glycemic variability showed correlations with oxidative stress and erythrocyte membrane stability variables. This corroborates the hypothesis that glycemic fluctuations interfere with lipid peroxidation and cell membrane behavior, emphasizing its participation in mechanisms related to the development of chronic complications of diabetes. Copyright © 2018 Elsevier B.V. All rights reserved.

Plasmodium falciparum merozoite surface protein 1 - Glycosylation and localization to low-density, detergent-resistant membranes in the parasitized erythrocyte

DEFF Research Database (Denmark)

Hoessli, D.C.; Poincelet, M.; Gupta, Ramneek

2003-01-01

In addition to the major carbohydrate moieties of the glycosylphosphatidylinositol (GPI) anchor, we report that Plasmodium falciparum merozoite surface protein 1 (MSP-1) bears O-GlcNAc modifications predominantly in beta-anomeric configuration, in both the C- and N-terminal portions of the protein....... Subcellular fractionation of parasitized erythrocytes in the late trophozoite/schizont stage reveals that GPI-anchored C-terminal fragments of MSP-1 are recovered in Triton X-100 resistant, low-density membrane fractions. Our results suggest that O -GlcNAc-modified MSP-1 N-terminal fragments tend to localize...... within the parasitophorous vacuolar membrane while GPI-anchored MSP-1 C-terminal fragments associate with low-density, Triton X-100 resistant membrane domains (rafts), redistribute in the parasitized erythrocyte and are eventually shed as membrane vesicles that also contain the endogenous, GPI-linked CD...

Experiment study and FEM simulation on erythrocytes under linear stretching of optical micromanipulation

Science.gov (United States)

Liu, Ying; Song, Huadong; Zhu, Panpan; Lu, Hao; Tang, Qi

2017-08-01

The elasticity of erythrocytes is an important criterion to evaluate the quality of blood. This paper presents a novel research on erythrocytes' elasticity with the application of optical tweezers and the finite element method (FEM) during blood storage. In this work, the erythrocytes with different in vitro times were linearly stretched by trapping force using optical tweezers and the time dependent elasticity of erythrocytes was investigated. The experimental results indicate that the membrane shear moduli of erythrocytes increased with the increasing in vitro time, namely the elasticity was decreasing. Simultaneously, an erythrocyte shell model with two parameters (membrane thickness h and membrane shear modulus H) was built to simulate the linear stretching states of erythrocytes by the FEM, and the simulations conform to the results obtained in the experiment. The evolution process was found that the erythrocytes membrane thicknesses were decreasing. The analysis assumes that the partial proteins and lipid bilayer of erythrocyte membrane were decomposed during the in vitro preservation of blood, which results in thin thickness, weak bending resistance, and losing elasticity of erythrocyte membrane. This study implies that the FEM can be employed to investigate the inward mechanical property changes of erythrocyte in different environments, which also can be a guideline for studying the erythrocyte mechanical state suffered from different diseases.

Relationship between changes of plasma endothelin (ET) level, ATPase activity of erythrocyte membrane and development of nephropathy in patients with pregnancy induced hypertension

International Nuclear Information System (INIS)

Qin Lin; Lu Beiyi

2008-01-01

Objective: To investigate the possible role played by alteration of plasma ET levels and activities of Na + - K + -APT ase and Ca 2+ -Mg 2+ -ATPase of erythrocyte membrane in patients with nephropathy pregnancy induced hypertension. Methods: The concentrations of plasma ET was detected with RIA and erythrocyte membrane ATPase activities were determined with Reilni method in 32 pregnant women with PIH complicated with nephropathy and 70 women with PIH but no nephropathy and 35 normal pregnant women as controls. Results: The plasma ET levels in patients with PHI (both with and without nephropathy) were significantly higher than those in normal preganat women (P + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase levels were significantly de- creased (P + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase activity of erythrocyte membrane. (authors)

Effect of reagent charge on the labeling of erythrocyte membrane proteins by photoactivated reagents

International Nuclear Information System (INIS)

Schaeffer, J.C.; Hakimian, R.; Shimer, M.L.

1986-01-01

Leaky erythrocyte ghosts were labeled with 3 H-[2-(4-azido-2-nitroanilino)ethyl]trimethylammonium iodide (cationic label) or 3 H-N-(4-azido-2-nitrophenyl)-β-alanine (anionic label). After the membranes were thoroughly washed, seven times as much cationic label was associated with the membranes as anionic label at 5 μM, whereas at 50 μM the cationic label was favored 15-fold. The distribution of label in the membrane proteins was ascertain by SDS-gel electrophoresis followed by autoradiography. At 50 μM cationic label, erythrocyte membrane protein bands 1,2,3,4.2, and 5 were intensely labeled, while band 6 was labeled weakly. At 5 μM cationic label, bands 1 and 4.2 were heavily labeled, while 2,3 and 5 were labeled less well. At both 50 μM and 5 μM anionic label, bands 1 and 6 were most prominently labeled. Bands 2,3,4.2 and 5 were labeled also at 50 μM, but they were labeled only very weakly at 5 μM. Band 4.1 was labeled very poorly if at all by either reagent. A mixture of the reagents gave an additive pattern. Thus, the charge and concentration of these reagents appear to play a major role in their ability to label membrane proteins indiscriminately. Because these reagents contain the same chromophore, 4-azido-2-nitroaniline, and differ mainly only in their charge, they may prove useful in assessing the location of charged sites on proteins in supramolecular complexes

Expression of Plasmodium falciparum erythrocyte membrane protein 1 in experimentally infected humans

DEFF Research Database (Denmark)

Lavstsen, Thomas; Magistrado, Pamela; Hermsen, Cornelus C

2005-01-01

-encoded Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family, which is expressed on the surface of infected erythrocytes where it mediates binding to endothelial receptors. Thus, severe malaria may be caused by parasites expressing PfEMP1 variants that afford parasites optimal sequestration...... in immunologically naive individuals and high effective multiplication rates. METHODS: var gene transcription was analysed using real time PCR and PfEMP1 expression by western blots as well as immune plasma recognition of parasite cultures established from non-immune volunteers shortly after infection with NF54...... compared to parasites expressing other var genes. The differential expression of PfEMP1 was confirmed at the protein level by immunoblot analysis. In addition, serological typing showed that immune sera more often recognized second and third generation parasites than first generation parasites. CONCLUSION...

P-gp expression in brown trout erythrocytes: evidence of a detoxification mechanism in fish erythrocytes.

Science.gov (United States)

Valton, Emeline; Amblard, Christian; Wawrzyniak, Ivan; Penault-Llorca, Frederique; Bamdad, Mahchid

2013-12-05

Blood is a site of physiological transport for a great variety of molecules, including xenobiotics. Blood cells in aquatic vertebrates, such as fish, are directly exposed to aquatic pollution. P-gp are ubiquitous "membrane detoxification proteins" implicated in the cellular efflux of various xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs), which may be pollutants. The existence of this P-gp detoxification system inducible by benzo [a] pyrene (BaP), a highly cytotoxic PAH, was investigated in the nucleated erythrocytes of brown trout. Western blot analysis showed the expression of a 140-kDa P-gp in trout erythrocytes. Primary cultures of erythrocytes exposed to increasing concentrations of BaP showed no evidence of cell toxicity. Yet, in the same BaP-treated erythrocytes, P-gp expression increased significantly in a dose-dependent manner. Brown trout P-gp erythrocytes act as membrane defence mechanism against the pollutant, a property that can be exploited for future biomarker development to monitor water quality.

Are aortic endograft prostheses fully hemo-compatible? A dielectric spectroscopy investigation of the electrical alterations induced on erythrocyte cell membranes

International Nuclear Information System (INIS)

Basoli, Antonio; Bordi, Federico; Cametti, Cesare; Faraglia, Vittorio; Gili, Tommaso; Rizzo, Luigi; Taurino, Maurizio

2007-01-01

In this paper we present a new approach directed to ascertain the full hemo-compatibility of aortic endograft prostheses based on the measurement of the passive electrical parameters of the erythrocyte cell membrane. The red blood cell membrane, from an electric point of view, is characterized by an electrical permittivity, ε s , which takes into account the structural charged organization of the lipid double layer, and by the electrical conductivity, σ s , which accounts for the ionic transport processes across the membrane. These parameters can be easily measured by means of a radiowave dielectric spectroscopy technique, analyzing the dependence of the electrical impedance of an erythrocyte suspension on the frequency of the applied electric field. In this preliminary report, we investigate the alterations induced, at a membrane level, by two different devices commonly employed for endovascular abdominal aortic aneurysm exclusion, i.e., Excluder (registered) and Zenith (registered) devices, implanted in ten patients. We observe, in all the cases investigated, a statistically significant increase of both the permittivity ε s and electrical conductivity σ s of the erythrocyte membrane upon the prosthesis implant, this increase being higher than about 20% of the un-treated values. Moreover, these alterations remain roughly unaffected 30 days after surgery. These findings suggest that a complete hemo-compatibility of these prostheses is lacking, even if the observed alterations may not have a clinical relevance

Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

International Nuclear Information System (INIS)

Mitamura, Yoshinori; Okamoto, Eiji

2015-01-01

This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier–Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field. - Highlights: • Effects of a gradient magnetic field on erythrocytes in an oxygenator were analyzed. • Blood changes magnetic susceptibility depending on if it is carrying oxygen or not. • Oxygenation of deoxygenated blood is effective for pressure rise in a magnetic field. • A membrane oxygenator works as an actuator. • There is a possibility of self-circulation of blood through an oxygenator

Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

Energy Technology Data Exchange (ETDEWEB)

Mitamura, Yoshinori, E-mail: ymitamura@par.odn.ne.jp; Okamoto, Eiji, E-mail: okamoto@tspirit.tokai-u.jp

2015-04-15

This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier–Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field. - Highlights: • Effects of a gradient magnetic field on erythrocytes in an oxygenator were analyzed. • Blood changes magnetic susceptibility depending on if it is carrying oxygen or not. • Oxygenation of deoxygenated blood is effective for pressure rise in a magnetic field. • A membrane oxygenator works as an actuator. • There is a possibility of self-circulation of blood through an oxygenator.

Effects of Three Kinds of Curcuminoids on Anti-Oxidative System and Membrane Deformation of Human Peripheral Blood Erythrocytes in High Glucose Levels

Directory of Open Access Journals (Sweden)

Wei Yang

2015-01-01

Full Text Available Background/Aims: Curcuminoids are the main bioactive constituents of the rhizome of turmeric. Erythrocytes lesions in diabetes are probably related to hyperglycemia and protein glycation. It has been reported that curcumin prevent lipid peroxidation. However, reports on the effects of demethoxycurcumin and bis-demethoxycurcumin on human erythrocytes at high glucose levels are scarce. Our aim is to investigate the effect of curcuminoids on oxidative stress and membrane of erythrocytes exposed to hyperglycemic condition. Methods: In this study, the different blood samples were treated with two doses of glucose (10 or 30 mM to mimic hyperglycemia in the presence or absence of three kinds of curcuminoids (5 or 10 μM in a medium at 37 °C for 24 h (Each experiment consists of 20 blood samples from 10 male and 10 female volunteers. The malondialdehyde was checked by HPLC, antioxidase (GSH and GSSG were measured by LC/MS, SOD was checked by WST-1 kit, morphology and phospholipid symmetry were detected by flow cytometry, confocal scanning microscope and scanning electron microscope. Results: The results illustrated that all three curcuminoids reduce oxidative stress damage on the membrane and maintain a better profile for erythrocytes. Furthermore, three curcuminoids had benefit effects on antioxidase. Conclusion: The three kinds of curcuminoids supplementation may prevent lipid peroxidation at different intensity and membrane dysfunction of human erythrocytes in hyperglycemia.

An Improved 2-Dimensional Gel Electrophoresis Method for Resolving Human Erythrocyte Membrane Proteins.

Science.gov (United States)

Kumar, Manoj; Singh, Rajendra; Meena, Anil; Patidar, Bhagwan S; Prasad, Rajendra; Chhabra, Sunil K; Bansal, Surendra K

2017-01-01

The 2-dimensional gel electrophoresis (2-DE) technique is widely used for the analysis of complex protein mixtures extracted from biological samples. It is one of the most commonly used analytical techniques in proteomics to study qualitative and quantitative protein changes between different states of a cell or an organism (eg, healthy and diseased), conditionally expressed proteins, posttranslational modifications, and so on. The 2-DE technique is used for its unparalleled ability to separate thousands of proteins simultaneously. The resolution of the proteins by 2-DE largely depends on the quality of sample prepared during protein extraction which increases results in terms of reproducibility and minimizes protein modifications that may result in artifactual spots on 2-DE gels. The buffer used for the extraction and solubilization of proteins influences the quality and reproducibility of the resolution of proteins on 2-DE gel. The purification by cleanup kit is another powerful process to prevent horizontal streaking which occurs during isoelectric focusing due to the presence of contaminants such as salts, lipids, nucleic acids, and detergents. Erythrocyte membrane proteins serve as prototypes for multifunctional proteins in various erythroid and nonerythroid cells. In this study, we therefore optimized the selected major conditions of 2-DE for resolving various proteins of human erythrocyte membrane. The modification included the optimization of conditions for sample preparation, cleanup of protein sample, isoelectric focusing, equilibration, and storage of immobilized pH gradient strips, which were further carefully examined to achieve optimum conditions for improving the quality of protein spots on 2-DE gels. The present improved 2-DE analysis method enabled better detection of protein spots with higher quality and reproducibility. Therefore, the conditions established in this study may be used for the 2-DE analysis of erythrocyte membrane proteins for

Impact of oxygen toxic action on the erythrocyte membrane and possibility of estimating central nervous system function disturbances

Directory of Open Access Journals (Sweden)

Belić Branislava

2011-01-01

Full Text Available Background/Aim. Prolonged exposure to hyperbaric oxygen leads to changes of erythrocytes shape as a consequence of toxic effects of oxygen on the erythrocyte membrane. The aim of this study was to examine the association between occurance of pathological forms of erythrocytes at different time from the start of hyperbaric oxygenation and the moment of convulsions occurrence, an interrelationship of different pathological forms of erythrocytes during exposure to hyperbaric oxygenation, as well as the correlation between the presence of ruptured erythrocytes and function of central nervous system (CNS after completion of hyperbaric treatment. Methods. Sixty laboratory mice, Mus musculus, were exposed to the wholly-oxygen pressure of 3.5 absolute atmospheres (ATA. Blood was collected at the 32nd, 34th, 36th, 38th and 40th minutes after the exposure to oxygen. Pathological forms of erythrocytes were examined by electron microscopy. A moment of convulsions occurrence was registered in all animals. After decompression neurological examinations of experimental animals were perfomed. The Pearson's coefficient of correlation, and linear regression equations for the parameters outlined in the aim of the study were calculated. Results. Hyperbaric oxygen caused damages of erythrocytes at the 34th minute after beginning of the treatment. Various forms of abnormal red blood cells occured, and immediately before the occurrence of irreversible changes (erythrocyte membrane rupture echinocyte shape was dominated. A significant correlation between the number of damaged red blood cells at 34th minute and their number at the 36th, 38th and 40th minute was found. Convulsions were diagnosed significantly earlier in mice with a greater number of damaged red blood cells (p < 0.01. There was a negative correlation between the number of irreversiblly damaged red blood cells (ruptured at the 40th minute and neurological score in the studied animals (p < 0.05. Conclusion

Erythrocytes Membrane Alterations Reflecting Liver Damage in CCl₄-Induced Cirrhotic Rats: The Ameliorative Effect of Naltrexone

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Fatemeh Sarhadi Kholari

2016-11-01

Full Text Available Cirrhosis is the consequence of chronic liver disease. Deleterious effects of oxidative stress on hepatocytes may be reflected in the erythrocyte membrane. Naltrexone (NTX has been shown to attenuate hepatocellular injury in fibrotic animal models. The aim of this study was to investigate the progressive effect of CCl4 on the liver and whether the improvement of liver cirrhosis can be monitored through alterations in the erythrocyte membrane. In this study, 84 male Wistar rats were divided into 4 groups and received reagents (i.p. as follows: 1- CCl₄, 2- NTX + CCl₄, 3- Mineral Oil (M, and 4- NTX + M. After 2, 6 and 8 weeks, the blood and liver tissue samples were collected. Plasma enzyme activities, the content of erythrocyte GSH and some membrane compositions, including protein carbonyl, protein sulfhydryl, and malondialdehyde were assessed. After 6 and 8 weeks, plasma enzyme activities and the content of protein carbonyl were higher in CCl4 group significantly, as compared to other groups (P<0.001. NTX significantly diminished protein carbonyl and plasma enzyme activities (P<0.001. GSH did not change until the 6th week. However, CCl4+NTX increased it significantly as compared to CCl₄ group (P<0.05. Protein sulfhydryl showed changes in NTX+CCl₄ group which indicated a significant increase in protein sulfhydryl content in a 6th week compared to CCl4 group (P<0.05. MDA did not show any significant alteration. CCl₄-induced cirrhosis is accompanied by increased content of oxidative stress markers, especially protein carbonyl of RBC membrane and plasma enzyme activities. This study shows that the progression of liver cirrhosis and the ameliorative effect of NTX can be followed through alterations of these markers.

Are aortic endograft prostheses fully hemo-compatible? A dielectric spectroscopy investigation of the electrical alterations induced on erythrocyte cell membranes

Energy Technology Data Exchange (ETDEWEB)

Basoli, Antonio [Clinica Chirurgica II, Universita di Roma ' La Sapienza' , Rome (Italy); Bordi, Federico [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Rome (Italy); Cametti, Cesare [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Rome (Italy); Faraglia, Vittorio [Cattedra di Chirurgia Vascolare, Second School of Medicine, Universita di Roma ' La Sapienza' , Rome (Italy); Gili, Tommaso [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Rome (Italy); Rizzo, Luigi [Cattedra di Chirurgia Vascolare, Second School of Medicine, Universita di Roma ' La Sapienza' , Rome (Italy); Taurino, Maurizio [Cattedra di Chirurgia Vascolare, Second School of Medicine, Universita di Roma ' La Sapienza' , Rome (Italy)

2007-03-01

In this paper we present a new approach directed to ascertain the full hemo-compatibility of aortic endograft prostheses based on the measurement of the passive electrical parameters of the erythrocyte cell membrane. The red blood cell membrane, from an electric point of view, is characterized by an electrical permittivity, {epsilon}{sub s}, which takes into account the structural charged organization of the lipid double layer, and by the electrical conductivity, {sigma}{sub s}, which accounts for the ionic transport processes across the membrane. These parameters can be easily measured by means of a radiowave dielectric spectroscopy technique, analyzing the dependence of the electrical impedance of an erythrocyte suspension on the frequency of the applied electric field. In this preliminary report, we investigate the alterations induced, at a membrane level, by two different devices commonly employed for endovascular abdominal aortic aneurysm exclusion, i.e., Excluder (registered) and Zenith (registered) devices, implanted in ten patients. We observe, in all the cases investigated, a statistically significant increase of both the permittivity {epsilon}{sub s} and electrical conductivity {sigma}{sub s} of the erythrocyte membrane upon the prosthesis implant, this increase being higher than about 20% of the un-treated values. Moreover, these alterations remain roughly unaffected 30 days after surgery. These findings suggest that a complete hemo-compatibility of these prostheses is lacking, even if the observed alterations may not have a clinical relevance.

Equilibrium thermodynamics of the partitioning of non-steroidal anti-inflammatory drugs into human erythrocyte ghost membranes

International Nuclear Information System (INIS)

Omran, Ahmed A.

2013-01-01

Graphical abstract: Bar diagram representing thermodynamic parameters obtained for the partitioning of NSAIDs into human erythrocyte ghost membranes at physiological pH; 7.4. Highlights: • Partition coefficients of NSAIDs into HEG membranes were determined. • Thermodynamic parameters were evaluated and successfully analyzed. • Partitioning of NSAIDs into HEG membranes was exothermic. • Partitioning of NSAIDs into HEG is spontaneous with negative free energy values. • Identical partitioning enthalpy–entropy driven compensation mechanism was shown. -- Abstract: In this work,second derivative spectrophotometry was applied for determining the partition coefficients (K p s) of four non-steroidal anti-inflammatory drugs (NSAIDs; flufenamic, meclofenamic, mefenamic and niflumic acids) into human erythrocyte ghost (HEG) membranes over a temperature range from (283.2 to 313.2) K. The proposed method allowed the evaluation and direct analyses of thermodynamic parameters; enthalpy (ΔH W→M ), Gibbs energy (ΔG W→M ) and entropy (ΔS W→M ) changes of the partitioning of NSAIDs into HEG membranes. The partitioning of NSAIDs between polar aqueous phase and non-polar lipid bilayer HEG membrane phase was exothermic with negative (ΔH W→M ) which compensated for the changes in (ΔS W→M ). The negative values of (ΔG W→M ) revealed that the partitioning of NSAIDs into HEG, owing to their transfer from polar aqueous phase and non-polar HEG phase is spontaneous. The enthalpy–entropy correlation analysis resulted in a good linearity that suggests an identical partitioning enthalpy–entropy driven compensation mechanism for the studied NSAIDs

Changes in the Fatty Acid Profile and Phospholipid Molecular Species Composition of Human Erythrocyte Membranes after Hybrid Palm and Extra Virgin Olive Oil Supplementation.

Science.gov (United States)

Pacetti, D; Gagliardi, R; Balzano, M; Frega, N G; Ojeda, M L; Borrero, M; Ruiz, A; Lucci, P

2016-07-13

This work aims to evaluate and compare, for the first time, the effects of extra virgin olive oil (EVOO) and hybrid palm oil (HPO) supplementation on the fatty acid profile and phospholipid (PL) molecular species composition of human erythrocyte membranes. Results supported the effectiveness of both HPO and EVOO supplementation (3 months, 25 mL/day) in decreasing the lipophilic index of erythrocytes with no significant differences between HPO and EVOO groups at month 3. On the other hand, the novel and rapid ultraperformance liquid chromatography-tandem mass spectrometry method used for PL analysis reveals an increase in the levels of phosphatidylcholine and phosphatidylethanolamine species esterified with polyunsaturated fatty acids. This work demonstrates the ability of both EVOO and HPO to increase the degree of unsaturation of erythrocyte membrane lipids with an improvement in membrane fluidity that could be associated with a lower risk of developing cardiovascular diseases.

Python erythrocytes are resistant to α-hemolysin from Escherichia coli.

Science.gov (United States)

Larsen, Casper K; Skals, Marianne; Wang, Tobias; Cheema, Muhammad U; Leipziger, Jens; Praetorius, Helle A

2011-12-01

α-Hemolysin (HlyA) from Escherichia coli lyses mammalian erythrocytes by creating nonselective cation pores in the membrane. Pore insertion triggers ATP release and subsequent P2X receptor and pannexin channel activation. Blockage of either P2X receptors or pannexin channels reduces HlyA-induced hemolysis. We found that erythrocytes from Python regius and Python molurus are remarkably resistant to HlyA-induced hemolysis compared to human and Trachemys scripta erythrocytes. HlyA concentrations that induced maximal hemolysis of human erythrocytes did not affect python erythrocytes, but increasing the HlyA concentration 40-fold did induce hemolysis. Python erythrocytes were more resistant to osmotic stress than human erythrocytes, but osmotic stress tolerance per se did not confer HlyA resistance. Erythrocytes from T. scripta, which showed higher osmotic resistance than python erythrocytes, were as susceptible to HlyA as human erythrocytes. Therefore, we tested whether python erythrocytes lack the purinergic signalling known to amplify HlyA-induced hemolysis in human erythrocytes. P. regius erythrocytes increased intracellular Ca²⁺ concentration and reduced cell volume when exposed to 3 mM ATP, indicating the presence of a P2X₇-like receptor. In addition, scavenging extracellular ATP or blocking P2 receptors or pannexin channels reduced the HlyA-induced hemolysis. We tested whether the low HlyA sensitivity resulted from low affinity of HlyA to the python erythrocyte membrane. We found comparable incorporation of HlyA into human and python erythrocyte membranes. Taken together, the remarkable HlyA resistance of python erythrocytes was not explained by increased osmotic resistance, lack of purinergic hemolysis amplification, or differences in HlyA affinity.

Effects of cobalt-60 ionizing radiation on human erythrocyte and its membrane proteins

International Nuclear Information System (INIS)

Amancio, Francisco Fernandes

1998-01-01

Ionizing radiation has several uses, as sterilization and radiotherapy, by its effects on living beings. recently, it has been used, at relatively lower doses (25 Gy), on blood for transfusions, mainly to eliminate undesirable graft host reactions, for use in multi transfused or immunocompromised patients. Here, we study the effect of larger doses of cobalt-60 ionizing radiation (25-1600 Gy) on human erythrocytes, by cytometric, physiologic, biochemical and immunological methods, looking for its effects and its detection. The red cells presented a clear dose-dependent increase in this volume, when irradiated in doses higher than 200 Gy, more significant in stored blood, but without hemolysis. Osmotic fragility was increased only after irradiation of more than 400 Gy. By ektacytometry, there was a lower deformability of irradiated red cells, at low stress (0.3 Pa), similar to capillary flow, but without alteration in higher stress (3 Pa), found in cardiac chambers. By SDS-PAGE, it was demonstrated that irradiated isolated erythrocyte membranes had aggregation of spectrin molecules, and decay of bands with lower molecular mass. This effect could be attributed to the radiation-induced hydroxyl radical, by specific scavenger studies. Those modifications were both antigenic and immunogenic in experimental animals, and the induced antibodies recognizes, by ELISA and immunoblot, both native or irradiated membrane proteins. They recognize rather irradiated whole erythrocyte than native ones, by hemagglutination, indirect immunofluorescence or flow cytometry assays. Our data suggests that human red cells could be irradiated at higher doses than those usually employed, with possible effect on other contaminant pathogens, without loss of viability of its use in transfusions. After improvements, irradiation induced epitopes detection could be a new tool in biological dosimetry. (author)

The AMP-activated protein kinase beta 1 subunit modulates erythrocyte integrity.

Science.gov (United States)

Cambridge, Emma L; McIntyre, Zoe; Clare, Simon; Arends, Mark J; Goulding, David; Isherwood, Christopher; Caetano, Susana S; Reviriego, Carmen Ballesteros; Swiatkowska, Agnieszka; Kane, Leanne; Harcourt, Katherine; Adams, David J; White, Jacqueline K; Speak, Anneliese O

2017-01-01

Failure to maintain a normal in vivo erythrocyte half-life results in the development of hemolytic anemia. Half-life is affected by numerous factors, including energy balance, electrolyte gradients, reactive oxygen species, and membrane plasticity. The heterotrimeric AMP-activated protein kinase (AMPK) is an evolutionarily conserved serine/threonine kinase that acts as a critical regulator of cellular energy balance. Previous roles for the alpha 1 and gamma 1 subunits in the control of erythrocyte survival have been reported. In the work described here, we studied the role of the beta 1 subunit in erythrocytes and observed microcytic anemia with compensatory extramedullary hematopoiesis together with splenomegaly and increased osmotic resistance. Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

Effects of gamma-irradiation on the erythrocyte membrane: ESR, NMR and biochemical studies

International Nuclear Information System (INIS)

Cantafora, A.; Ceccarini, M.; Guidoni, L.; Ianzini, F.; Minetti, M.; Viti, V.

1987-01-01

The effects of gamma-irradiation on resealed erythrocyte ghosts have been examined with different techniques. Phospholipid analysis reveals peroxidative damage on the polyunsaturated chains of phosphatidylethanolamine. Gel electrophoresis and ESR measurements indicate modifications of the cytoskeletal proteins. 31 P nuclear magnetic resonance data show bilayer modifications that can be interpreted as changes in lipid-protein interactions. The overall picture from the present results favours interaction between lipids and proteins in the inner monolayer of the membrane. (author)

Significant decrease of saturation index in erythrocytes membrane from subjects with non-alcoholic fatty liver disease (NAFLD).

Science.gov (United States)

Notarnicola, Maria; Caruso, Maria Gabriella; Tutino, Valeria; Bonfiglio, Caterina; Cozzolongo, Raffaele; Giannuzzi, Vito; De Nunzio, Valentina; De Leonardis, Giampiero; Abbrescia, Daniela I; Franco, Isabella; Intini, Vincenza; Mirizzi, Antonella; Osella, Alberto R

2017-08-23

The lipidomic profiling of erythrocyte membranes is expected to provide a peculiar scenario at molecular level of metabolic and nutritional pathways which may influence the lipid balance and the adaptation and homeostasis of the organism. Considering that lipid accumulation in the cell is important in promoting tissue inflammation, the purpose of this study is to analyze the fatty acid profile in red blood cell membranes of patients with Non-Alcoholic Fatty Liver Disease (NAFLD), in order to identify and validate membrane profiles possibly associated with the degree of hepatic damage. This work presents data obtained at baseline from 101 subjects that participated to a nutritional trial (registration number: NCT02347696) enrolling consecutive subjects with NAFLD. Diagnosis of liver steatosis was performed by using vibration-controlled elastography implemented on FibroScan. Fatty acids, extracted from phospholipids of erythrocyte membranes, were quantified by gas chromatography method. The subjects with severe NAFLD showed a significant decrease of the ratio of stearic acid to oleic acid (saturation index, SI) compared to controls, 1.281 ± 0.31 vs 1.5 ± 0.29, respectively. Low levels of SI in red blood cell membranes, inversely associated with degree of liver damage, suggest that an impairment of circulating cell membrane structure can reflect modifications that take place in the liver. Subjects with severe NAFLDalso showed higher levels of elongase 5 enzymatic activity, evaluated as vaccenic acid to palmitoleic acid ratio. Starting from these evidences, our findings show the importance of lipidomic approach in the diagnosis and the staging of NAFLD.

Dual fluorescence labeling of surface-exposed and internal proteins in erythrocytes infected with the malaria parasite Plasmodium falciparum

DEFF Research Database (Denmark)

Bengtsson, Dominique C; Sowa, Kordai M P; Arnot, David E

2008-01-01

There is a need for improved methods for in situ localization of surface proteins on Plasmodium falciparum-infected erythrocytes to help understand how these antigens are trafficked to, and positioned within, the host cell membrane. This protocol for confocal immunofluorescence microscopy combines...... and permeabilization; indirect labeling of the internal antigen using a secondary antibody tagged with a spectrally distinct fluorescent dye; and detection of the differentially labeled antigens using a laser scanning confocal microscope. The protocol can be completed in approximately 7 h. Although the protocol...... surface antigen labeling on live cells with subsequent fixation and permeabilization, which enables antibodies to penetrate the cell and label internal antigens. The key steps of the protocol are as follows: indirect labeling of the surface antigen using a fluorescently tagged secondary antibody; fixation...

Antioxidant activity of erythrocyte membranes of rats exposed to X-radiation and injected with α-tocopheral acetate

International Nuclear Information System (INIS)

Tsvetkova, T.V.; Tsokur, Eh.V.

1988-01-01

Injection of α-tocopherol acetate to albino mongrel rats potentiates antioxidant activity (AOA) that involves water-soluble factors of the antioxidant system in erythrocyte membranes. The activation of AOA by a α-tocopherol takes place immediately after irradiation and drug injection and persists during the first 24 h following irradiation

Influence of styryl dyes on blood erythrocytes

Science.gov (United States)

Nizomov, Negmat; Barakaeva, Mubaro; Kurtaliev, Eldar N.; Rahimov, Sherzod I.; Khakimova, Dilorom P.; Khodjayev, Gayrat; Yashchuk, Valeriy N.

2008-08-01

It was studied the influence of F, Sbt, Sil, Sbo monomer and homodimer Dst-5, Dst-10, Dbt-5, Dbt-10, Dil-10, Dbo-10 styryl dyes on blood erythrocytes of white rats. It was shown that the homodimer styryl dyes Dst-5, Dbt-5 and Dbo-10 decrease the erythrocytes quantity by 1.5-2 times more as compared with monomer dyes Sbt and Sbo. The main cause of dyes different action is the different oxidation degree of intracellular hemoglobin evoked by these dyes. It was established that the observed effects was connected with different penetration of these dyes through membrane of erythrocytes and with interaction of these dyes with albumin localized in membranes of cells.

Erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy

Science.gov (United States)

Zhu, Dao-Ming; Xie, Wei; Xiao, Yu-Sha; Suo, Meng; Zan, Ming-Hui; Liao, Qing-Quan; Hu, Xue-Jia; Chen, Li-Ben; Chen, Bei; Wu, Wen-Tao; Ji, Li-Wei; Huang, Hui-Ming; Guo, Shi-Shang; Zhao, Xing-Zhong; Liu, Quan-Yan; Liu, Wei

2018-02-01

Recently, red blood cell (RBC) membrane-coated nanoparticles have attracted much attention because of their excellent immune escapability; meanwhile, gold nanocages (AuNs) have been extensively used for cancer therapy due to their photothermal effect and drug delivery capability. The combination of the RBC membrane coating and AuNs may provide an effective approach for targeted cancer therapy. However, few reports have shown the utilization of combining these two technologies. Here, we design erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy. First, anti-EpCam antibodies were used to modify the RBC membranes to target 4T1 cancer cells. Second, the antitumor drug paclitaxel (PTX) was encapsulated into AuNs. Then, the AuNs were coated with the modified RBC membranes. These new nanoparticles were termed EpCam-RPAuNs. We characterized the capability of the EpCam-RPAuNs for selective tumor targeting via exposure to near-infrared irradiation. The experimental results demonstrate that EpCam-RPAuNs can effectively generate hyperthermia and precisely deliver the antitumor drug PTX to targeted cells. We also validated the biocompatibility of the EpCam-RAuNs in vitro. By combining the molecularly modified targeting RBC membrane and AuNs, our approach provides a new way to design biomimetic nanoparticles to enhance the surface functionality of nanoparticles. We believe that EpCam-RPAuNs can be potentially applied for cancer diagnoses and therapies.

Leucine - /sup 14/C transport through erythrocyte cell membrane in newborns with hypertrophic constriction of the pylorus

Energy Technology Data Exchange (ETDEWEB)

Stepniewski, M; Janik, A [Akademia Medyczna, Krakow (Poland)

1980-01-01

In 12 newborns with hypertrophic constriction of the pylorus the coefficient of the leucine - /sup 14/C distribution in the erythrocyte intracellular twice: the first time during day prior the operation corresponding to advanced malnutrition of the newborns, and the second time seven days after pylorotomy. During the second period the effects of hyponutrition were partially balanced. The obtained data were compared with that noted in 12 healthy newborns and additionally with data of examination done with samples of conserved blood. In newborns with hypertrophic constriction of the pylorus the coefficient of leucine distribution prior the operation was significantly lower than that in the control group and conserved blood. After seven days from operation a significant increase of above coefficient is compared with the control group and erythrocytes in conserved blood has been noted. Above results suggest that disturbances in penetration of leucine through cell membranes of erythrocytes are in association with malnutrition caused by constriction of the pylorus.

Protective Effects of Ferulic Acid on High Glucose-Induced Protein Glycation, Lipid Peroxidation, and Membrane Ion Pump Activity in Human Erythrocytes.

Directory of Open Access Journals (Sweden)

Weerachat Sompong

Full Text Available Ferulic acid (FA is the ubiquitous phytochemical phenolic derivative of cinnamic acid. Experimental studies in diabetic models demonstrate that FA possesses multiple mechanisms of action associated with anti-hyperglycemic activity. The mechanism by which FA prevents diabetes-associated vascular damages remains unknown. The aim of study was to investigate the protective effects of FA on protein glycation, lipid peroxidation, membrane ion pump activity, and phosphatidylserine exposure in high glucose-exposed human erythrocytes. Our results demonstrated that FA (10-100 μM significantly reduced the levels of glycated hemoglobin (HbA1c whereas 0.1-100 μM concentrations inhibited lipid peroxidation in erythrocytes exposed to 45 mM glucose. This was associated with increased glucose consumption. High glucose treatment also caused a significant reduction in Na+/K+-ATPase activity in the erythrocyte plasma membrane which could be reversed by FA. Furthermore, we found that FA (0.1-100 μM prevented high glucose-induced phosphatidylserine exposure. These findings provide insights into a novel mechanism of FA for the prevention of vascular dysfunction associated with diabetes.

Human erythrocytes and neuroblastoma cells are affected in vitro by Au(III) ions

International Nuclear Information System (INIS)

Suwalsky, Mario; Gonzalez, Raquel; Villena, Fernando; Aguilar, Luis F.; Sotomayor, Carlos P.; Bolognin, Silvia; Zatta, Paolo

2010-01-01

Gold compounds are well known for their neurological and nephrotoxic implications. However, haematological toxicity is one of the most serious toxic and less studied effects. The lack of information on these aspects of Au(III) prompted us to study the structural effects induced on cell membranes, particularly that of human erythrocytes. AuCl 3 was incubated with intact erythrocytes, isolated unsealed human erythrocyte membranes (IUM) and molecular models of the erythrocyte membrane. The latter consisted of multibilayers of dimyristoylphosphatidylcholine and dimyristoylphosphatidylethanolamine, phospholipids classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively. This report presents evidence that Au(III) interacts with red cell membranes as follows: (a) in scanning electron microscopy studies on human erythrocytes it was observed that Au(III) induced shape changes at a concentration as low as 0.01 μM; (b) in isolated unsealed human erythrocyte membranes Au(III) induced a decrease in the molecular dynamics and/or water content at the glycerol backbone level of the lipid bilayer polar groups in a 5-50 μM concentration range, and (c) X-ray diffraction studies showed that Au(III) in the 10 μm-1 mM range induced increasing structural perturbation only to dimyristoylphosphatidylcholine bilayers. Additional experiments were performed in human neuroblastoma cells SH-SY5Y. A statistically significant decrease of cell viability was observed with Au(III) ranging from 0.1 μM to 100 μM.

Molecular mechanisms of erythrocyte photo-irradiation

International Nuclear Information System (INIS)

Ferreira, W.T.; Souza, M.C.

1985-01-01

The role of singlet oxygen and the lipid peroxidation of erythrocyte membrane are studied. The irradiation of erythrocytes with visible light in the presence of a photodynamic mediator (toluidine blue) is reported. A system of light application by optical fiber, connected to a catheter is suggested for local instillation of the photosensitizing agent. (M.A.C.) [pt

Effect of shear stress and free radicals induced by ultrasound on erythrocytes

International Nuclear Information System (INIS)

Kondo, T.; Fukushima, Y.; Kon, H.; Riesz, P.

1989-01-01

The present study was undertaken to elucidate the mechanism of hemolysis induced by ultrasound. Ar or N2O gas was used to distinguish between cavitation with or without free radical formation (hydroxyl radicals and hydrogen atoms). Free radical formation was examined by the method of spin trapping combined with ESR. After sonication of erythrocyte suspensions, several structural and functional parameters of the erythrocyte membrane--hemolysis, membrane fluidity, membrane permeability, and membrane deformability--were examined. Although free radical formation was observed in the erythrocyte suspensions sonicated in the presence of Ar, no free radical formation was observed in the presence of N2O. However, the hemolysis behavior induced by ultrasound was similar in the presence of Ar or N2O. The membrane fluidity, permeability, and deformability of the remaining unlysed erythrocytes after sonication in the presence of Ar or N2O were unchanged and identical to those of the control cells. On the other hand, after gamma irradiation (700 Gy), the hemolysis behavior was quite different from that after sonication, and the membrane properties were significantly changed. These results suggest that hemolysis induced by sonication was due to mechanical shearing stress arising from cavitation, and that the membrane integrity of the remaining erythrocytes after sonication was the same as that of control cells without sonication. The triatomic gas, N2O, may be useful for ultrasonically disrupting cells without accompanying free radical formation

Expression of senescent antigen on erythrocytes infected with a knobby variant of the human malaria parasite Plasmodium falciparum

International Nuclear Information System (INIS)

Winograd, E.; Greenan, J.R.T.; Sherman, I.W.

1987-01-01

Erythrocytes infected with a knobby variant of Plasmodium falciparum selectively bind IgG autoantibodies in normal human serum. Quantification of membrane-bound IgG, by use of 125 I-labeled protein A, revealed that erythrocytes infected with the knobby variant bound 30 times more protein A than did noninfected erythrocytes; infection with a knobless variant resulted in less than a 2-fold difference compared with noninfected erythrocytes. IgG binding to knobby erythrocytes appeared to be related to parasite development, since binding of 125 I-labeled protein A to cells bearing young trophozoites (less than 20 hr after parasite invasion) was similar to binding to uninfected erythrocytes. By immunoelectron microscopy, the membrane-bound IgG on erythrocytes infected with the knobby variant was found to be preferentially associated with the protuberances (knobs) of the plasma membrane. The removal of aged or senescent erythrocytes from the peripheral circulation is reported to involve the binding of specific antibodies to an antigen (senescent antigen) related to the major erythrocyte membrane protein band 3. Since affinity-purified autoantibodies against band 3 specifically bound to the plasma membrane of erythrocytes infected with the knobby variant of P. falciparum, it is clear that the malaria parasite induces expression of senescent antigen

NMR studies of transmembrane electron transport in human erythrocytes

International Nuclear Information System (INIS)

Kennett, E.C.; Bubb, W.A.; Kuchel, P.W.

2002-01-01

Full text: Electron transport systems exist in the plasma membranes of all cells. These systems appear to play a role in cell growth and proliferation, intracellular signalling, hormone responses, apoptotic events, cell defence and perhaps most importantly they enable the cell to respond to changes in the redox state of both the intra- and extracellular environments. Previously, 13 C NMR has been used to study transmembrane electron transport in human erythrocytes, specifically the reduction of extracellular 13 C-ferricyanide. NMR is a particularly useful tool for studying such systems as changes in the metabolic state of the cell can be observed concomitantly with extracellular reductase activity. We investigated the oxidation of extracellular NADH by human erythrocytes using 1 H and 31 P NMR spectroscopy. Recent results for glucose-starved human erythrocytes indicate that, under these conditions, extracellular NADH can be oxidised at the plasma membrane with the electron transfer across the membrane resulting in reduction of intracellular NAD + . The activity is inhibited by known trans-plasma membrane electron transport inhibitors (capsaicin and atebrin) and is unaffected by inhibition of the erythrocyte Band 3 anion transporter. These results suggest that electron import from extracellular NADH allows the cell to re-establish a reducing environment after the normal redox balance is disturbed

Determination of glucose exchange rates and permeability of erythrocyte membrane in preeclampsia and subsequent oxidative stress-related protein damage using dynamic-{sup 19}F-NMR

Energy Technology Data Exchange (ETDEWEB)

Dickinson, Elizabeth, E-mail: elizabeth.dickinson@york.ac.uk [University of York, Department of Chemistry (United Kingdom); Arnold, John R. P. [Selby College (United Kingdom); Fisher, Julie [University of Leeds, School of Chemistry (United Kingdom)

2017-02-15

The cause of the pregnancy condition preeclampsia (PE) is thought to be endothelial dysfunction caused by oxidative stress. As abnormal glucose tolerance has also been associated with PE, we use a fluorinated-mimic of this metabolite to establish whether any oxidative damage to lipids and proteins in the erythrocyte membrane has increased cell membrane permeability. Data were acquired using {sup 19}F Dynamic-NMR (DNMR) to measure exchange of 3-fluoro-3-deoxyglucose (3-FDG) across the membrane of erythrocytes from 10 pregnant women (5 healthy control women, and 5 from women suffering from PE). Magnetisation transfer was measured using the 1D selective inversion and 2D EXSY pulse sequences, over a range of time delays. Integrated intensities from these experiments were used in matrix diagonalisation to estimate the values of the rate constants of exchange and membrane permeability. No significant differences were observed for the rate of exchange of 3-FDG and membrane permeability between healthy pregnant women and those suffering from PE, leading us to conclude that no oxidative damage had occurred at this carrier-protein site in the membrane.

Determination of glucose exchange rates and permeability of erythrocyte membrane in preeclampsia and subsequent oxidative stress-related protein damage using dynamic-"1"9F-NMR

International Nuclear Information System (INIS)

Dickinson, Elizabeth; Arnold, John R. P.; Fisher, Julie

2017-01-01

The cause of the pregnancy condition preeclampsia (PE) is thought to be endothelial dysfunction caused by oxidative stress. As abnormal glucose tolerance has also been associated with PE, we use a fluorinated-mimic of this metabolite to establish whether any oxidative damage to lipids and proteins in the erythrocyte membrane has increased cell membrane permeability. Data were acquired using "1"9F Dynamic-NMR (DNMR) to measure exchange of 3-fluoro-3-deoxyglucose (3-FDG) across the membrane of erythrocytes from 10 pregnant women (5 healthy control women, and 5 from women suffering from PE). Magnetisation transfer was measured using the 1D selective inversion and 2D EXSY pulse sequences, over a range of time delays. Integrated intensities from these experiments were used in matrix diagonalisation to estimate the values of the rate constants of exchange and membrane permeability. No significant differences were observed for the rate of exchange of 3-FDG and membrane permeability between healthy pregnant women and those suffering from PE, leading us to conclude that no oxidative damage had occurred at this carrier-protein site in the membrane.

Comparative evaluation of haematological parameters and erythrocyte membrane stability in pregnant and lactating goats in different seasons of tropical Savannah.

Science.gov (United States)

Habibu, B; Makun, H J; Yaqub, L S; Buhari, H U; Aluwong, T; Kawu, M U

2017-09-01

Haematological parameters and erythrocyte osmotic fragility (EOF) are commonly used as indicators of health status and erythrocyte membrane integrity. Variations in haematological parameters and EOF in late gestation and early lactation during the cold-dry (CDS), hot-dry (HDS) and rainy (RAS) seasons were studied in sixty (n = 60) Red Sokoto goats (20 goats for each season). The ambient temperatures and temperature-humidity index recorded were higher in the afternoon hours of the HDS and RAS, but lower in the morning hours of the CDS as compared with the thermoneutral zone of goats. Results revealed that the pregnant goats had significantly (P goats, higher (P goats. The EOF was significantly higher during lactation than pregnancy in the CDS and HDS. Similarly, the magnitude of the left shift in fragiligram during the CDS was more marked in pregnant compared with lactating goats. During gestation, the CDS had lower (P goats during the CDS. In conclusion, seasonal variations exist in physiology of erythrocytes of goats during the peri-partum period, with an increase in PCV and RBC, but a decrease in haemoglobin parameters in pregnant compared with lactating goats during the RAS. Erythrocyte stability and membrane integrity were higher in pregnant than lactating goats, and also higher during the CDS than the HDS and RAS, irrespective of reproductive status. This information may be useful in the design of animal breeding and is of value in animal welfare, research, diagnosis and management of haematological conditions during the peri-partum period. Copyright © 2017 Elsevier Inc. All rights reserved.

Role of plasma membrane and of cytomatrix in maintenance of intracellular to extracellular ion gradients in chicken erythrocytes

International Nuclear Information System (INIS)

Cameron, I.L.; Hunter, K.E.; Smith, N.K.; Hazlewood, C.F.; Ludany, A.; Kellermayer, M.

1988-01-01

Ultrastructural observations in combination with electron probe X-ray microanalysis on detergent (Brij 58) permeabilized (disruption of the plasma membrane) nucleated chicken erythrocytes support the view that a large fraction of cytoplasmic and nuclear K+ is not freely diffusible and that adsorption of K+ on detergent released mobilizable proteins exists within the cell. The data also suggest that the detergent proteins are normally immobilized by a detergent-resistant cytoskeleton so that they are not immediately free to diffuse from the cell for several minutes after detergent disruption of the plasma membrane

MPP1 directly interacts with flotillins in erythrocyte membrane - Possible mechanism of raft domain formation.

Science.gov (United States)

Biernatowska, Agnieszka; Augoff, Katarzyna; Podkalicka, Joanna; Tabaczar, Sabina; Gajdzik-Nowak, Weronika; Czogalla, Aleksander; Sikorski, Aleksander F

2017-11-01

Flotillins are prominent, oligomeric protein components of erythrocyte (RBC) membrane raft domains and are considered to play an important structural role in lateral organization of the plasma membrane. In our previous work on erythroid membranes and giant plasma membrane vesicles (GPMVs) derived from them we have shown that formation of functional domains (resting state rafts) depends on the presence of membrane palmitoylated protein 1 (MPP1/p55), pointing to its new physiological role. Exploration of the molecular mechanism of MPP1 function in organizing membrane domains described here, through searching for its molecular partners in RBC membrane by using different methods, led to the identification of the raft-marker proteins, flotillin 1 and flotillin 2, as hitherto unreported direct MPP1 binding-partners in the RBC membrane. These proteins are found in high molecular-weight complexes in native RBC membrane and, significantly, their presence was shown to be separate from the well-known protein 4.1-dependent interactions of MPP1 with membrane proteins. Furthermore, FLIM analysis revealed that loss of the endogenous MPP1-flotillins interactions resulted in significant changes in RBC membrane-fluidity, emphasizing the physiological importance of such interactions in vivo. Therefore, our data establish a new perspective on the role of MPP1 in erythroid cells and suggests that direct MPP1-flotillins interactions could be the major driving-force behind the formation of raft domains in RBC. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Nutrition and Reproductive Health: Sperm versus Erythrocyte Lipidomic Profile and ω-3 Intake

Directory of Open Access Journals (Sweden)

Gabriela Ruth Mendeluk

2015-01-01

Full Text Available Fatty acid analyses of sperm and erythrocyte cell membrane phospholipids in idiopathic infertile patients evidenced that erythrocyte contents of EPA, DHA, omega-6–omega-3 ratio and arachidonic acid provide a mathematical correspondence for the prediction of EPA level in sperm cells. The erythrocyte lipidomic profile of patients was significantly altered, with signatures of typical Western pattern dietary habits and no fish intake. A supplementation with nutritional levels of EPA and DHA and antioxidants was then performed for 3 months, with the follow-up of both erythrocyte and sperm cell membranes composition as well as conventional sperm parameters. Some significant changes were found in the lipidomic membrane profile of erythrocyte but not in sperm cells, which correspondently did not show significant parameter ameliorations. This is the first report indicating that membrane lipids of different tissues do not equally metabolize the fatty acid elements upon supplementation. Molecular diagnostic tools are necessary to understand the cell metabolic turnover and monitor the success of nutraceuticals for personalized treatments.

Plasma and erythrocyte membrane phospholipids and fatty acids in Italian general population and hemodialysis patients.

Science.gov (United States)

Dessì, Mariarita; Noce, Annalisa; Bertucci, Pierfrancesco; Noce, Gianluca; Rizza, Stefano; De Stefano, Alessandro; Manca di Villahermosa, Simone; Bernardini, Sergio; De Lorenzo, Antonino; Di Daniele, Nicola

2014-03-21

Dyslipidemia and abnormal phospholipid metabolism are frequent in uremic patients and increase their risk of cardiovascular disease (CVD): ω-3 polyunsaturated fatty acids (PUFAs) may reduce this risk in the general population. In this study we compared the plasma and erythrocyte cell membrane composition of PUFAs in a group of Caucasian hemodialysis (HD) patients and in a control group of healthy subjects and evaluated the erythrocyte/cell membrane fatty acid ratio as a marker of the dietary intake of phospholipids. The relationship between ω-3 and ω-6 fatty acids and the possible differences in PUFAs concentrations were also investigated. After obtaining a fully informed consent, a total of ninety-nine HD patients and 160 non uremic control subjects from "Tor Vergata" University Hospital were enrolled into the study. None of them took antioxidant drugs or dietary supplements for at least 90 days prior to the observation. Blood samples were analysed by gas-chromatographic coupled to a mass spectrometric detector.The daily intake of total calories, proteins, lipids and carbohydrates is significantly lower in HD patients than in controls (p HD patients (p HD patients, due to the removal of nutrients during the dialysis and to persistent malnutrition. A dietary treatment addressed to increase plasma ω-3 PUFAs and to optimize ω-6/ω-3 ratio may exert a protective action and reduce the risk of CVD in HD patient.

The osmotic fragility of human erythrocytes is inhibited by laser irradiation

International Nuclear Information System (INIS)

Habodaszova, D.; Sikurova, L.; Waczulikova, I.

2004-01-01

In this study we investigated the influence of green laser irradiation (532 nm, 30 mW, 31,7 J/cm 2 ) on the membrane integrity of human erythrocytes and compared the results with the effect of infrared laser irradiation (810 nm, 50 mW, 31,3 J/cm 2 ). To evaluate the membrane integrity of erythrocytes, one clinical parameter, the osmotic fragility, was investigated. We observed a decrease in osmotic fragility of the erythrocytes after irradiation by the green laser light as well as by the infrared laser compared to non-irradiated controls (Authors)

Modulation of erythrocyte membrane mechanical stability by 2,3-diphosphoglycerate in the neonatal poikilocytosis/elliptocytosis syndrome.

OpenAIRE

Mentzer, W C; Iarocci, T A; Mohandas, N; Lane, P A; Smith, B; Lazerson, J; Hays, T

1987-01-01

To explain the transient anemia and poikilocytosis seen during infancy in hereditary elliptocytosis (HE), we resealed erythrocyte (RBC) ghosts from affected children or their elliptocytic parents with 2,3-diphosphoglycerate (DPG) (0-8 mM), a compound that dissociates membrane skeletons, then measured ghost mechanical stability in the ektacytometer. Without added 2,3-DPG, ghost mechanical stability was subnormal in infantile poikilocytosis (IP) and HE but was even more abnormal in hereditary p...

Growth of plasmodium falciparum in human erythrocytes containing abnormal membrane proteins

International Nuclear Information System (INIS)

Schulman, S.; Roth, E.F. Jr.; Cheng, B.; Rybicki, A.C.; Sussman, I.I.; Wong, M.; Nagel, R.L.; Schwartz, R.S.; Wang, W.; Ranney, H.M.

1990-01-01

To evaluate the role of erythrocyte (RBC) membrane proteins in the invasion and maturation of Plasmodium falciparum, the authors have studied, in culture, abnormal RBCs containing quantitative or qualitative membrane protein defects. These defects included hereditary spherocytosis (HS) due to decreases in the content of spectrin [HS(Sp + )], hereditary elliptocytosis (HE) due to protein 4.1 deficiency [HE(4.1 0 )], HE due to a spectrin αI domain structural variant that results in increased content of spectrin dimers [HE(Spα I/65 )], and band 3 structural variants. Parasite invasion, measured by the initial uptake of [ 3 H]hypoxanthine 18 hr after inoculation with merozoites, was normal in all of the pathologic RBCs. In contrast, RBCs from six HS(Sp + ) subjects showed marked growth inhibition that became apparent after the first or second growth cycle. The extent of decreased parasite growth in HS(Sp + ) RBCs closely correlated with the extent of RBC spectrin deficiency. Homogeneous subpopulations of dense HS RBCs exhibited decreased parasite growth to the same extent as did HS whole blood. RBCs from four HE subjects showed marked parasite growth and development

Examination of the calcium-erythrocyte membrane interactions

International Nuclear Information System (INIS)

Gardos, Gy.; Szasz, I.; Sarkadi, B.

1979-01-01

A review of the cation-transport mechanisms of human erythrocytes is given. The following experimental methods were applied: measurement of 45 Ca influx, 45 Ca efflux, 42 K influx, 42 K efflux, 22 Na efflux and determination of the activity of the Ca-ATP-ase enzyme. The increase of the intracellular Ca-level opens some specific K-channels, through which K is leaking out passively. The kinetics and the chemical nature of this K-transport are given in detail. On the other hand, Ca ions taken up are removed by active transport. Detailed data are given on the activity and specific inhibition of this Ca-pump. In human erythrocytes the pump is working with the stoichiometry of Ca:ATP=2. (L.E.)

Erythrocyte membrane-coated nanogel for combinatorial antivirulence and responsive antimicrobial delivery against Staphylococcus aureus infection.

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Zhang, Yue; Zhang, Jianhua; Chen, Wansong; Angsantikul, Pavimol; Spiekermann, Kevin A; Fang, Ronnie H; Gao, Weiwei; Zhang, Liangfang

2017-10-10

We reported an erythrocyte membrane-coated nanogel (RBC-nanogel) system with combinatorial antivirulence and responsive antibiotic delivery for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection. RBC membrane was coated onto the nanogel via a membrane vesicle templated in situ gelation process, whereas the redox-responsiveness was achieved by using a disulfide bond-based crosslinker. We demonstrated that the RBC-nanogels effectively neutralized MRSA-associated toxins in extracellular environment and the toxin neutralization in turn promoted bacterial uptake by macrophages. In intracellular reducing environment, the RBC-nanogels showed an accelerated drug release profile, which resulted in more effective bacterial inhibition. When added to the macrophages infected with intracellular MRSA bacteria, the RBC-nanogels significantly inhibited bacterial growth compared to free antibiotics and non-responsive nanogel counterparts. These results indicate the great potential of the RBC-nanogel system as a new and effective antimicrobial agent against MRSA infection. Copyright © 2017 Elsevier B.V. All rights reserved.

A method for visualizing surface-exposed and internal PfEMP1 adhesion antigens in Plasmodium falciparum infected erythrocytes

DEFF Research Database (Denmark)

Bengtsson, Dominique; Sowa, Kordai M; Salanti, Ali

2008-01-01

BACKGROUND: The insertion of parasite antigens into the host erythrocyte membrane and the structure and distribution of Plasmodium falciparum adhesion receptors on that membrane are poorly understood. Laser scanning confocal microscopy (LSCM) and a novel labelling and fixation method have been used...... fluorochromes has been developed for laser scanning confocal optical microscopy and the analysis of the developmental expression of malaria adhesion antigens....

Effects of Radiographic Contrast Media on the Micromorphology of the Junctional Complex of Erythrocytes Visualized by Immunocytology

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Franke, Ralf-Peter; Krüger, Anne; Scharnweber, Tim; Wenzel, Folker; Jung, Friedrich

2014-01-01

Effects of radiographic contrast media (RCM) application were demonstrated in vitro and in vivo where the injection of RCM into the A. axillaris of patients with coronary artery disease was followed by a significant and RCM-dependent decrease of erythrocyte velocity in downstream skin capillaries. Another study in pigs revealed that the deceleration of erythrocytes coincided with a significant reduction of the oxygen partial pressure in the myocardium—supplied by the left coronary artery—after the administration of RCM into this artery. Further reports showed RCM dependent alterations of erythrocytes like echinocyte formation and exocytosis, sequestration of actin or band 3 and the buckling of endothelial cells coinciding with a formation of interendothelial fenestrations leading to areas devoid of endothelial cells. Key to morphological alterations of erythrocytes is the membrane cytoskeleton, which is linked to the band 3 in the erythrocyte membrane via the junctional complex. Fundamental observations regarding the cell biological and biochemical aspects of the structure and function of the cell membrane and the membrane cytoskeleton of erythrocytes have been reported. This review focuses on recent results gained, e.g., by advanced confocal laser scanning microscopy of different double-stained structural elements of the erythrocyte membrane cytoskeleton. PMID:25222553

Age-dependent effects of He-Ne laser irradiation on the membrane fluidity of human erythrocytes

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Kovacs, Eugenia; Savopol, Tudor; Pologea-Moraru, Roxana; Makropoulou, Mersini I.; Serafetinides, Alexander A.

1997-12-01

The low power He-Ne laser radiation has been extensively used in past decades as medical device to relieve pain, accelerate wound healing as well as aiming beam in invisible laser beam in invisible laser beam applications. It is not known however if there are any secondary, undesirable effects of He-Ne laser radiation on the irradiated tissue. In this paper we investigate the changes induced in membrane fluidity of human erythrocyte during/upon the interaction with the He-Ne laser beam having the parameters currently used for target aiming in laser surgery.

Triggers, Inhibitors, Mechanisms, and Significance of Eryptosis: The Suicidal Erythrocyte Death

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Elisabeth Lang

2015-01-01

Full Text Available Suicidal erythrocyte death or eryptosis is characterized by erythrocyte shrinkage, cell membrane blebbing, and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca2+ entry, ceramide formation, stimulation of caspases, calpain activation, energy depletion, oxidative stress, and dysregulation of several kinases. Eryptosis is triggered by a wide variety of xenobiotics. It is inhibited by several xenobiotics and endogenous molecules including NO and erythropoietin. The susceptibility of erythrocytes to eryptosis increases with erythrocyte age. Phosphatidylserine exposing erythrocytes adhere to the vascular wall by binding to endothelial CXC-Motiv-Chemokin-16/Scavenger-receptor for phosphatidylserine and oxidized low density lipoprotein (CXCL16. Phosphatidylserine exposing erythrocytes are further engulfed by phagocytosing cells and are thus rapidly cleared from circulating blood. Eryptosis eliminates infected or defective erythrocytes thus counteracting parasitemia in malaria and preventing detrimental hemolysis of defective cells. Excessive eryptosis, however, may lead to anemia and may interfere with microcirculation. Enhanced eryptosis contributes to the pathophysiology of several clinical disorders including metabolic syndrome and diabetes, malignancy, cardiac and renal insufficiency, hemolytic uremic syndrome, sepsis, mycoplasma infection, malaria, iron deficiency, sickle cell anemia, thalassemia, glucose 6-phosphate dehydrogenase deficiency, and Wilson’s disease. Facilitating or inhibiting eryptosis may be a therapeutic option in those disorders.

Malaria Parasite CLAG3, a Protein Linked to Nutrient Channels, Participates in High Molecular Weight Membrane-Associated Complexes in the Infected Erythrocyte.

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Kayvan Zainabadi

Full Text Available Malaria infected erythrocytes show increased permeability to a number of solutes important for parasite growth as mediated by the Plasmodial Surface Anion Channel (PSAC. The P. falciparum clag3 genes have recently been identified as key determinants of PSAC, though exactly how they contribute to channel function and whether additional host/parasite proteins are required remain unknown. To begin to answer these questions, I have taken a biochemical approach. Here I have used an epitope-tagged CLAG3 parasite to perform co-immunoprecipitation experiments using membrane fractions of infected erythrocytes. Native PAGE and mass spectrometry studies reveal that CLAG3 participate in at least three different high molecular weight complexes: a ~720kDa complex consisting of CLAG3, RHOPH2 and RHOPH3; a ~620kDa complex consisting of CLAG3 and RHOPH2; and a ~480kDa complex composed solely of CLAG3. Importantly, these complexes can be found throughout the parasite lifecycle but are absent in untransfected controls. Extracellular biotin labeling and protease susceptibility studies localize the 480kDa complex to the erythrocyte membrane. This complex, likely composed of a homo-oligomer of 160kDa CLAG3, may represent a functional subunit, possibly the pore, of PSAC.

Antioxidant capacity of Ugni molinae fruit extract on human erythrocytes: an in vitro study.

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Suwalsky, Mario; Avello, Marcia

2014-08-01

Ugni molinae is an important source of molecules with strong antioxidant activity widely used as a medicinal plant in Southern Chile-Argentina. Total phenol concentration from its fruit extract was 10.64 ± 0.04 mM gallic acid equivalents. Analysis by means of HPLC/MS indicated the presence of the anthocyanins cyanidin and peonidin, and the flavonol quercitin, all in glycosylated forms. Its antioxidant properties were assessed in human erythrocytes in vitro exposed to HClO oxidative stress. Scanning electron microscopy showed that HClO induced an alteration in erythrocytes from a normal shape to echinocytes; however, this change was highly attenuated in samples containing U. molinae extracts. It also had a tendency in order to reduce the hemolytic effect of HClO. In addition, X-ray diffraction experiments were performed in dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine bilayers, classes of lipids preferentially located in the outer and inner monolayers, respectively, of the human erythrocyte membrane. It was observed that U. molinae only interacted with DMPC. Results by fluorescence spectroscopy on DMPC large unilamellar vesicles and isolated unsealed human erythrocyte membranes also showed that it interacted with the erythrocyte membrane and DMPC. It is possible that the location of U. molinae components into the membrane outer monolayer might hinder the diffusion of HClO and of free radicals into cell membranes and the consequent decrease of the kinetics of free radical reactions.

Morphological Effects and Antioxidant Capacity of Solanum crispum (Natre) In Vitro Assayed on Human Erythrocytes.

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Suwalsky, Mario; Ramírez, Patricia; Avello, Marcia; Villena, Fernando; Gallardo, María José; Barriga, Andrés; Manrique-Moreno, Marcela

2016-06-01

In order to gain insight into the molecular mechanism of the antioxidant properties of Solanum crispum, aqueous extracts of its leaves were assayed on human erythrocytes and molecular models of its membrane. Phenolics and alkaloids were detected by HPLC-MS. Scanning electron and defocusing microscopy showed that S. crispum changed erythrocytes from the normal shape to echinocytes. These results imply that molecules present in the aqueous extracts were located in the outer monolayer of the erythrocyte membrane. Dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were chosen as representative of phospholipid classes located in the outer and inner monolayers of the erythrocyte membrane, respectively. X-ray diffraction showed that S. crispum preferentially interacted with DMPC bilayers. Experiments regarding its antioxidant properties showed that S. crispum neutralized the oxidative capacity of HClO on DMPE bilayers; defocusing microscopy and hemolysis assays demonstrated the protective effect of S. crispum against the oxidant effects of HClO on human erythrocytes.

Biophysical Properties of Irradiated Erythrocytes and Role of Antioxidants

International Nuclear Information System (INIS)

Eman Mohammed Elbakrawy, E.M.

2010-01-01

Irradiation of blood and blood components with gamma-irradiation is recommended for the inactivation of T-lymphocytes and prevention of transfusion-associated graft versus host diseases. The aim of the present work is to ensure that the currently applied irradiation dose 25 Gy is a safe dose based on the study of the electrical behavior, rheological properties, membrane solubilization, membrane hemolysis and scanning electron microscope of stored erythrocytes. In addition it aims to study the possibility of increasing the irradiation doses to 50 and 100 Gy. Moreover Alpha lipoic acid (a potent natural antioxidant) was added to the stored erythrocytes before irradiation for radioprotection. Irradiation of erythrocytes with 25 Gy did not show significant changes for the calculated dielectric parameters. However, increasing the irradiation doses resulted in significant decrease in the calculated dielectric parameters reflecting the damaging effects of radiation on the membrane structure. The obtained results showed that α lipoic acid can play an important role in minimizing the radiation-induced damage to the erythrocytes and conserve their electrical properties. There were non-significant changes in viscosity after exposure to 25 Gy, while a significant increase at 50 Gy and a significant decrease at 100 Gy were observed. The study found that α lipoic acid (ALA) resulted in non-significant change in viscosity after exposure to 50 Gy and 100 Gy. A significant increase in the yield stress was observed after exposure to 25 and 50 Gy while at 100 Gy, the yield stress showed a remarkable decrease. Addition of .-lipoic acid before irradiation resulted in non-significant changes in the yield stress at doses 25, 50, 100 Gy.The obtained results of the average membrane solubilization (D 50 ) and the average membrane hemolysis (H 50 ) showed non-significant change at 25 Gy; while an observable decrease was observed at 50 Gy and 100 Gy. The addition of lipoic acid did not

Effect of pH on molecular constitution and distribution of hemoglobin in living erythrocyte.

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Wu, Yue; Huang, Yao-Xiong; Kang, Li-Li; Wu, Zheng-Jie; Luo, Man

2010-04-01

The molecular constitution of in situ hemoglobin (Hb) and their distribution in living erythrocyte were investigated versus pH using the technique of confocal Raman microscopy. Both Raman point spectra and line mapping measurements were performed on living erythrocytes in suspensions with pH values from 4.82 to 9.70. It was found that the Hb inside a living erythrocyte would dissociate into monomer/dimer when the cells are in low and high pH environments. In contrast to the homogeneous distribution of the Hbs in the cells in neutral suspension, there are more Hbs distributing around the cell membrane or binding to the membrane as pH increases. While in low pH, as the cell become spherical, most of the Hbs distribute to the central part of the cell. In summary, our investigation suggests that the variation of the external pH not only brings changes in the morphology and membrane structure of an erythrocyte, but also affects the constitution and distribution of its intracellular Hbs, thereby the flexibility of the cell membrane and the oxygenation ability of the Hb.

Physical and Chemical Processes and the Morphofunctional Characteristics of Human Erythrocytes in Hyperglycaemia

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Victor V. Revin

2017-08-01

Full Text Available Background: This study examines the effect of graduated hyperglycaemia on the state and oxygen-binding ability of hemoglobin, the correlation of phospholipid fractions and their metabolites in the membrane, the activity of proteolytic enzymes and the morphofunctional state of erythrocytes.Methods: Conformational changes in the molecule of hemoglobin were determined by Raman spectroscopy. The structure of the erythrocytes was analyzed using laser interference microscopy (LIM. To determine the activity of NADN-methemoglobinreductase, we used the P.G. Board method. The degree of glycosylation of the erythrocyte membranes was determined using a method previously described by Felkoren et al. Lipid extraction was performed using the Bligh and Dyer method. Detection of the phospholipids was performed using V. E. Vaskovsky method.Results: Conditions of hyperglycaemia are characterized by a low affinity of hemoglobin to oxygen, which is manifested as a parallel decrease in the content of hemoglobin oxyform and the growth of deoxyform, methemoglobin and membrane-bound hemoglobin. The degree of glycosylation of membrane proteins and hemoglobin is high. For example, in the case of hyperglycaemia, erythrocytic membranes reduce the content of all phospholipid fractions with a simultaneous increase in lysoforms, free fatty acids and the diacylglycerol (DAG. Step wise hyperglycaemia in incubation medium and human erythrocytes results in an increased content of peptide components and general trypsin-like activity in the cytosol, with a simultaneous decreased activity of μ-calpain and caspase 3.Conclusions: Metabolic disorders and damage of cell membranes during hyperglycaemia cause an increase in the population of echinocytes and spherocytes. The resulting disorders are accompanied with a high probability of intravascular haemolysis.

Local anesthetics: interaction with human erythrocyte membranes as studied by 1H and 31P nuclear magnetic resonance

International Nuclear Information System (INIS)

Fraceto, Leonardo Fernandes; Paula, Eneida de

2004-01-01

The literature carries many theories about the mechanism of action of local anesthetics (LA). We can highlight those focusing the direct effect of LA on the sodium channel protein and the ones that consider the interaction of anesthetic molecules with the lipid membrane phase. The interaction between local anesthetics and human erythrocyte membranes has been studied by 1 H and 31 P nuclear magnetic resonance spectroscopy. It was found that lidocaine (LDC) and benzocaine (BZC) bind to the membranes, increase the mobility of the protons of the phospholipids acyl chains, and decrease the mobility and/or change the structure of the polar head groups. The results indicate that lidocaine molecules are inserted across the polar and liquid interface of the membrane, establishing both electrostatic (charged form) and hydrophobic (neutral form) interactions. Benzocaine locates itself a little deeper in the bilayer, between the interfacial glycerol region and the hydrophobic core. These changes in mobility or conformation of membrane lipids could affect the Na + -channel protein insertion in the bilayer, stabilizing it in the inactivated state, thus causing anesthesia. (author)

Transport of 3-bromopyruvate across the human erythrocyte membrane.

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Sadowska-Bartosz, Izabela; Soszyński, Mirosław; Ułaszewski, Stanisław; Ko, Young; Bartosz, Grzegorz

2014-06-01

3-Bromopyruvic acid (3-BP) is a promising anticancer compound because it is a strong inhibitor of glycolytic enzymes, especially glyceraldehyde 3-phosphate dehydrogenase. The Warburg effect means that malignant cells are much more dependent on glycolysis than normal cells. Potential complications of anticancer therapy with 3-BP are side effects due to its interaction with normal cells, especially erythrocytes. Transport into cells is critical for 3-BP to have intracellular effects. The aim of our study was the kinetic characterization of 3-BP transport into human erythrocytes. 3-BP uptake by erythrocytes was linear within the first 3 min and pH-dependent. The transport rate decreased with increasing pH in the range of 6.0-8.0. The Km and Vm values for 3-BP transport were 0.89 mM and 0.94 mmol/(l cells x min), respectively. The transport was inhibited competitively by pyruvate and significantly inhibited by DIDS, SITS, and 1-cyano-4-hydroxycinnamic acid. Flavonoids also inhibited 3-BP transport: the most potent inhibition was found for luteolin and quercetin.

Optical Assay of Erythrocyte Function in Banked Blood

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Bhaduri, Basanta; Kandel, Mikhail; Brugnara, Carlo; Tangella, Krishna; Popescu, Gabriel

2014-09-01

Stored red blood cells undergo numerous biochemical, structural, and functional changes, commonly referred to as storage lesion. How much these changes impede the ability of erythrocytes to perform their function and, as result, impact clinical outcomes in transfusion patients is unknown. In this study we investigate the effect of the storage on the erythrocyte membrane deformability and morphology. Using optical interferometry we imaged red blood cell (RBC) topography with nanometer sensitivity. Our time-lapse imaging quantifies membrane fluctuations at the nanometer scale, which in turn report on cell stiffness. This property directly impacts the cell's ability to transport oxygen in microvasculature. Interestingly, we found that cells which apparently maintain their normal shape (discocyte) throughout the storage period, stiffen progressively with storage time. By contrast, static parameters, such as mean cell hemoglobin content and morphology do not change during the same period. We propose that our method can be used as an effective assay for monitoring erythrocyte functionality during storage time.

Role of band 3 in the erythrocyte membrane structural changes under thermal fluctuations -multi scale modeling considerations.

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Pajic-Lijakovic, Ivana

2015-12-01

An attempt was made to discuss and connect various modeling approaches on various time and space scales which have been proposed in the literature in order to shed further light on the erythrocyte membrane rearrangement caused by the cortex-lipid bilayer coupling under thermal fluctuations. Roles of the main membrane constituents: (1) the actin-spectrin cortex, (2) the lipid bilayer, and (3) the trans membrane protein band 3 and their course-consequence relations were considered in the context of the cortex non linear stiffening and corresponding anomalous nature of energy dissipation. The fluctuations induce alternating expansion and compression of the membrane parts in order to ensure surface and volume conservation. The membrane structural changes were considered within two time regimes. The results indicate that the cortex non linear stiffening and corresponding anomalous nature of energy dissipation are related to the spectrin flexibility distribution and the rate of its changes. The spectrin flexibility varies from purely flexible to semi flexible. It is influenced by: (1) the number of band 3 molecules attached to single spectrin filaments, and (2) phosphorylation of the actin-junctions. The rate of spectrin flexibility changes depends on the band 3 molecules rearrangement.

Caffeine inhibits erythrocyte membrane derangement by antioxidant activity and by blocking caspase 3 activation.

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Tellone, Ester; Ficarra, Silvana; Russo, Annamaria; Bellocco, Ersilia; Barreca, Davide; Laganà, Giuseppina; Leuzzi, Ugo; Pirolli, Davide; De Rosa, Maria Cristina; Giardina, Bruno; Galtieri, Antonio

2012-02-01

The aim of this research was to investigate the effect of caffeine on band 3 (the anion exchanger protein), haemoglobin function, caspase 3 activation and glucose-6-phosphate metabolism during the oxygenation-deoxygenation cycle in human red blood cells. A particular attention has been given to the antioxidant activity by using in vitro antioxidant models. Caffeine crosses the erythrocyte membrane and interacts with the two extreme conformational states of haemoglobin (the T and the R-state within the framework of the simple two states allosteric model) with different binding affinities. By promoting the high affinity state (R-state), the caffeine-haemoglobin interaction does enhance the pentose phosphate pathway. This is of benefit for red blood cells since it leads to an increase of NADPH availability. Moreover, caffeine effect on band 3, mediated by haemoglobin, results in an extreme increase of the anion exchange, particularly in oxygenated erythrocytes. This enhances the transport of the endogenously produced CO(2) thereby avoiding the production of dangerous secondary radicals (carbonate and nitrogen dioxide) which are harmful to the cellular membrane. Furthermore caffeine destabilizes the haeme-protein interactions within the haemoglobin molecule and triggers the production of superoxide and met-haemoglobin. However this damaging effect is almost balanced by the surprising scavenger action of the alkaloid with respect to the hydroxyl radical. These experimental findings are supported by in silico docking and molecular dynamics studies and by what we may call the "caspase silence"; in fact, there is no evidence of any caspase 3 activity enhancement; this is likely due to the promotion of positive metabolic conditions which result in an increase of the cellular reducing power. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Effect of radiographic contrast media on the spectrin/band3-network of the membrane skeleton of erythrocytes.

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Ralf-Peter Franke

Full Text Available The membrane of red blood cells consists of a phospholipid bilayer with embedded membrane proteins and is associated on the cytoplasmatic side with a network of proteins, the membrane skeleton. Band3 has an important role as centre of the functional complexes e.g. gas exchange complex and as element of attachment for the membrane skeleton maintaining membrane stability and flexibility. Up to now it is unclear if band3 is involved in the morphology change of red blood cells after contact with radiographic contrast media. The study revealed for the first time that Iopromide induced markedly more severe alterations of the membrane skeleton compared to Iodixanol whose effects were similar to erythrocytes suspended in autologous plasma. A remarkable clustering of band3 was found associated with an accumulation of band3 in spicules and also a sequestration of band3 to the extracellular space. This was evidently accompanied by a gross reduction of functional band3 complexes combined with a dissociation of spectrin from band3 leading to a loss of homogeneity of the spectrin network. It could be demonstrated for the first time that RCM not only induced echinocyte formation but also exocytosis of particles at least coated with band3.

Effect of Radiographic Contrast Media on the Spectrin/Band3-Network of the Membrane Skeleton of Erythrocytes

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Franke, Ralf-Peter; Scharnweber, Tim; Fuhrmann, Rosemarie; Wenzel, Folker; Krüger, Anne; Mrowietz, Christof; Jung, Friedrich

2014-01-01

The membrane of red blood cells consists of a phospholipid bilayer with embedded membrane proteins and is associated on the cytoplasmatic side with a network of proteins, the membrane skeleton. Band3 has an important role as centre of the functional complexes e.g. gas exchange complex and as element of attachment for the membrane skeleton maintaining membrane stability and flexibility. Up to now it is unclear if band3 is involved in the morphology change of red blood cells after contact with radiographic contrast media. The study revealed for the first time that Iopromide induced markedly more severe alterations of the membrane skeleton compared to Iodixanol whose effects were similar to erythrocytes suspended in autologous plasma. A remarkable clustering of band3 was found associated with an accumulation of band3 in spicules and also a sequestration of band3 to the extracellular space. This was evidently accompanied by a gross reduction of functional band3 complexes combined with a dissociation of spectrin from band3 leading to a loss of homogeneity of the spectrin network. It could be demonstrated for the first time that RCM not only induced echinocyte formation but also exocytosis of particles at least coated with band3. PMID:24586837

Limited cross-reactivity among domains of the Plasmodium falciparum clone 3D7 erythrocyte membrane protein 1 family

DEFF Research Database (Denmark)

Joergensen, Louise; Turner, Louise; Magistrado, Pamela

2006-01-01

The var gene-encoded Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family is responsible for antigenic variation and sequestration of infected erythrocytes during malaria. We have previously grouped the 60 PfEMP1 variants of P. falciparum clone 3D7 into groups A and B/A (category A......) and groups B, B/C, and C (category non-A). Expression of category A molecules is associated with severe malaria, and that of category non-A molecules is associated with uncomplicated malaria and asymptomatic infection. Here we assessed cross-reactivity among 60 different recombinant PfEMP1 domains derived...... from clone 3D7 by using a competition enzyme-linked immunosorbent assay and a pool of plasma from 63 malaria-exposed Tanzanian individuals. We conclude that naturally acquired antibodies are largely directed toward epitopes varying between different domains with a few, mainly category A, domains...

Effect of complete protein 4.1R deficiency on ion transport properties of murine erythrocytes

International Nuclear Information System (INIS)

Rivera, Alicia; De Franceschi, Lucia; Peters, Luanne L.; Gascard, Philippe; Mohandas, Narla; Brugnara, Carlo

2006-01-01

Moderate hemolytic anemia, abnormal erythrocyte morphology (spherocytosis), and decreased membrane stability are observed in mice with complete deficiency of all erythroid protein 4.1 protein isoforms (4.1-/-; Shi TS et al., J. Clin. Invest. 103:331,1999). We have examined the effects of erythroid protein 4.1 (4.1R) deficiency on erythrocyte cation transport and volume regulation. 4.1-/- mice exhibited erythrocyte dehydration that was associated with reduced cellular K and increased Na content. Increased Na permeability was observed in these mice, mostly mediated by Na/H exchange with normal Na-K pump and Na-K-2Cl cotransport activities. The Na/H exchange of 4.1-/- erythrocytes was markedly activated by exposure to hypertonic conditions (18.2+- 3.2 in 4.1 -/- vs.9.8 +- 1.3 mmol/1013 cell x h in control mice), with an abnormal dependence on osmolarity, (K0.5=417 +- 42 in 4.1 -/- vs. 460 +- 35 mOsmin control mice) suggestive of an up-regulated functional state. While the affinity for internal protons was not altered (K0.5= 489.7 +- 0.7 vs.537.0 +- 0.56 nM in control mice), the Vmax of the H-induced Na/H exchange activity was markedly elevated in 4.1-/- erythrocytes Vmax 91.47 Moderate hemolytic anemia, abnormal erythrocyte morphology (spherocytosis), and decreased membrane stability are observed in mice with complete deficiency of all erythroid protein 4.1 protein isoforms (4.1-/-; Shi TSet al., J. Clin. Invest. 103:331,1999). We have examined the effects of erythroid protein 4.1 (4.1R) deficiency on erythrocyte cation transport and volume regulation. 4.1-/- mice exhibited erythrocyte dehydration that was associated with reduced cellular K and increased Na content. Increased Na permeability was observed in these mice, mostly mediated by Na/H exchange with normal Na-K pump and Na-K-2Cl cotransport activities. The Na/H exchange of 4.1-/- erythrocytes was markedly activated by exposure to hypertonic conditions (18.2 +- 3.2 in 4.1 -/- vs. 9.8 +- 1.3mmol/1013 cell x h in

Erythrocytes in alternating electric fields

International Nuclear Information System (INIS)

Morariu, V.V.; Chifu, A.; Simplaceanu, T.; Frangopol, P.T.

1983-02-01

The elastic and inelastic deformation of erythrocytes induced by alternating fields and the suggestion that moderate field intensities (1.2 kV/cm) when continuously applied can cause lysis by a different mechanism compared to the action of short intense field pulses is presented. The different experimental conditions can be used to approach various properties of the membrane such as those related to the dielectric polarization of the membrane or to the interfacial polarization, leading to the inelastic deformation of the cells. (authors)

Phosphorylation of intact erythrocytes in human muscular dystrophy

International Nuclear Information System (INIS)

Johnson, R.M.; Nigro, M.

1986-01-01

The uptake of exogenous 32 Pi into the membrane proteins of intact erythrocytes was measured in 8 patients with Duchenne muscular dystrophy. No abnormalities were noted after autoradiographic analysis. This contrasts with earlier results obtained when isolated membranes were phosphorylated with gamma-[ 32 P]ATP, and suggests a possible reinterpretation of those experiments

Hereditary spherocytosis and elliptocytosis associated with prosthetic heart valve replacement: rheological study of erythrocyte modifications.

Science.gov (United States)

Caprari, Patrizia; Tarzia, Anna; Mojoli, Giorgio; Cianciulli, Paolo; Mannella, Emilio; Martorana, Maria Cristina

2009-04-01

The implantation of a prosthetic heart valve (HVP) in patients with hereditary spherocytosis (HS) and hereditary elliptocytosis (HE) is rare, and the changes in the structure and deformability of erythrocytes that follow implantation in these patients have been poorly described. In the present study, the erythrocytes in HS and HE patients with mechanical HVP were compared to the erythrocytes in patients with only congenital membrane defects, in terms of biochemical modifications and rheological behaviour. Integral and cytoskeletal erythrocyte membrane proteins were studied, and blood viscosity (shear rate/shear stress ratio), aggregation ratio [eta(1 s(-1))/eta(200 s(-1))], and red cell visco-elasticity were determined. Valve replacement with a mechanical prosthesis worsened anaemia and resulted in a change in haemolysis, from sub-clinical to evident. The rheological investigation of erythrocytes from HS patients confirmed the characteristic increased viscosity and aggregation ratio and the decreased deformability. The rheological behaviour of erythrocytes from patients with HVP showed a decrease in viscosity and an increase in elastic modulus. In these patients, the prosthesis seems to have induced traumatic damage to the erythrocyte membrane, leading to fragmentation and lysis, which in turn modified rheological parameters. The biochemical and rheological investigation allowed us to understand the clinical and haematological pictures of the patients and to describe the role played by different factors in haemolytic anaemia.

Clotrimazole enhances lysis of human erythrocytes induced by t-BHP.

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Lisovskaya, Irene L; Shcherbachenko, Irina M; Volkova, Rimma I; Ataullakhanov, Fazoil I

2009-08-14

Clotrimazole (CLT) is an antifungal and antimalarial agent also effective as a Gardos channel inhibitor. In addition, CLT possesses antitumor properties. Recent data provide evidence that CLT forms a complex with heme (hemin), which produces a more potent lytic effect than heme alone. This study addressed the effect of CLT on the lysis of normal human erythrocytes induced by tert-butyl hydroperoxide (t-BHP). For the first time, it was shown that 10 microM CLT significantly enhanced the lytic effect of t-BHP on erythrocytes in both Ca(2+)-containing and Ca(2+)-free media, suggesting that the effect is not related to Gardos channels. CLT did not affect the rate of free radical generation, the kinetics of GSH degradation, methemoglobin formation and TBARS generation; therefore, we concluded that CLT does not cause additional oxidative damage to erythrocytes treated with t-BHP. It is tempted to speculate that CLT enhances t-BHP-induced changes in erythrocyte volume and lysis largely by forming a complex with hemin released during hemoglobin oxidation in erythrocytes: the CLT-hemin complex destabilizes the cell membrane more potently than hemin alone. If so, the effect of CLT on cell membrane damage during free-radical oxidation may be used to increase the efficacy of antitumor therapy.

A single-cell technique for the measurement of membrane potential, membrane conductance, and the efflux of rapidly penetrating solutes in Amphiuma erythrocytes.

Science.gov (United States)

Stoner, L C; Kregenow, F M

1980-10-01

We describe a single-cell technique for measuring membrane potential, membrane resistance, and the efflux of rapidly penetrating solutes such as Cl and H2O. Erythrocytes from Amphiuma means were aspirated into a Sylgard (Dow Corning Corp.)-coated capillary. The aspirated cell separated a solution within the capillary from a solution in the bath. Each of these two solutions was contiguous with approximately 5% of the total membrane surface. Microelectrodes placed concentrically within the capillary permit the measurement of intracellular voltage, specific membrane resistance, and the electrical seal between the two solutions. The intracellular voltage averaged -17.7 mV (pH 7.6) and changed as either intra- or extracellular chloride was varied. The average specific membrane resistance measured by passing current across the exposed membrane surface was 110 ohm-cm2. 36Cl and tritiated H2O fluxes (0.84 +/- 0.05 x 10(-6) M . cm-2 . min-1 and 6.4 +/- 1.5 x 10(-3) M . cm-2 . min-1, respectively) were determined by noting the rate at which isotope leaves the cell and crosses the membrane exposed to the bath. Our measured values for the flux of 36Cl and tritiated H2O approximate reported values for free-floating cells. 36Cl efflux, in addition, is inhibited by 4-acetamido-4'-isothiocyano-stilbene 2,2'-disulfonic acid (SITS) and furosemide, known inhibitors of the anion exchange mechanism responsible for the rapid anion fluxes of red blood cells. One can also demonstrate directly that > 89% of 36Cl efflux is "electrically silent" by analyzing the flux in the presence of an imposed transcellular voltage.

Stimulation of Suicidal Erythrocyte Death by the Antimalarial Drug Mefloquine

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Rosi Bissinger

2015-07-01

Full Text Available Background: The antimalarial drug mefloquine has previously been shown to stimulate apoptosis of nucleated cells. Similar to apoptosis, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, increase of cytosolic Ca2+-activity ([Ca2+]i, and ceramide. Methods: Phosphatidylserine abundance at the cell surface was estimated from annexin V binding, cell volume from forward scatter, reactive oxidant species (ROS from 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA fluorescence, [Ca2+]i from Fluo3-fluorescence, and ceramide abundance from specific antibody binding. Results: A 48 h treatment of human erythrocytes with mefloquine significantly increased the percentage of annexin-V-binding cells (≥5 µg/ml, significantly decreased forward scatter (≥5 µg/ml, significantly increased ROS abundance (5 µg/ml, significantly increased [Ca2+]i (7.5 µg/ml and significantly increased ceramide abundance (10 µg/ml. The up-regulation of annexin-V-binding following mefloquine treatment was significantly blunted but not abolished by removal of extracellular Ca2+. Even in the absence of extracellular Ca2+, mefloquine significantly increased annexin-V-binding. Conclusions: Mefloquine treatment leads to erythrocyte shrinkage and erythrocyte membrane scrambling, effects at least partially due to induction of oxidative stress, increase of [Ca2+]i and up-regulation of ceramide abundance.

Membrane polypeptide in rabbit erythrocytes associated with the inhibition of L-lactate transport by a synthetic anhydride of lactic acid

International Nuclear Information System (INIS)

Donovan, J.A.; Jennings, M.L.

1985-01-01

The synthetic lactyl anhydride isobutylcarbonyl lactyl anhydride (iBCLA), a selective and potent inhibitor of L-(+)-lactate transport in rabbit erythrocytes, reduces the chemical labeling of a 40-50-kdalton polypeptide by tritiated 4,4'-diisothiocyanato-2,2'-dihydrostilbenedisulfonate ([ 3 H]H 2 DIDS). iBCLA does so in a dose-dependent manner at concentrations that strongly inhibit lactate-lactate exchange but not chloride-phosphate exchange. These labeling experiments and inhibition reversal studies using iBCLA, p-(chloro-mercuri)benzenesulfonic acid (pCMBS), and dithiothreitol (DDT) suggest that iBCLA does not act at sulfhydryl groups but at or near an amino group that is near a disulfide linkage in the polypeptide which catalyzes lactate transport. These experiments support the association between specific monocarboxylate transport and a 40-50-kdalton membrane-bound polypeptide of the rabbit erythrocyte

Curcumin Protects -SH Groups and Sulphate Transport after Oxidative Damage in Human Erythrocytes

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Rossana Morabito

2015-05-01

Full Text Available Background/Aims: Erythrocytes, continuously exposed to oxygen pressure and toxic compounds, are sensitive to oxidative stress, namely acting on integral Band 3 protein, with consequences on cell membranes deformability and anion transport efficiency. The aim of the present investigation, conducted on human erythrocytes, is to verify whether curcumin (1 or 10µM, a natural compound with proved antioxidant properties, may counteract Band 3-mediated anion transport alterations due to oxidative stress. Methods: Oxidative conditions were induced by exposure to, alternatively, either 2 mM N-ethylmaleimide (NEM or pH-modified solutions (6.5 and 8.5. Rate constant for SO4= uptake and -SH groups estimation were measured to verify the effect of oxidative stress on anion transport efficiency and erythrocyte membranes. Results: After the exposure of erythrocytes to, alternatively, NEM or pH-modified solutions, a significant decrease in both rate constant for SO4= uptake and -SH groups was observed, which was prevented by curcumin, with a dose-dependent effect. Conclusions: Our results show that: i the decreased efficiency of anion transport may be due to changes in Band 3 protein structure caused by cysteine -SH groups oxidation, especially after exposure to NEM and pH 6.5; ii 10 µM Curcumin is effective in protecting erythrocytes from oxidative stress events at level of cell membrane transport.

Clofazimine Induced Suicidal Death of Human Erythrocytes

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Arbace Officioso

2015-08-01

Full Text Available Background/Aims: The antimycobacterial riminophenazine clofazimine has previously been shown to up-regulate cellular phospholipase A2 and to induce apoptosis. In erythrocytes phospholipase A2 stimulates eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Phospholipase A2 is in part effective by fostering formation of prostaglandin E2, which triggers Ca2+ entry. Stimulators of Ca2+ entry and eryptosis further include oxidative stress and energy depletion. The present study tested, whether and how clofazimine induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, hemolysis from hemoglobin release, cytosolic Ca2+ activity ([Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS from 2′, 7′-dichlorodihydrofluorescein diacetate (DCFDA fluorescence, and cytosolic ATP level utilizing a luciferin-luciferase assay kit. Results: A 24-48 hours exposure of human erythrocytes to clofazimine (≥1.5 µg/ml significantly increased the percentage of annexin-V-binding cells without appreciably modifying forward scatter. Clofazimine significantly increased [Ca2+]i, significantly decreased cytosolic ATP, but did not significantly modify ROS. The effect of clofazimine on annexin-V-binding was significantly blunted, but not fully abolished by removal of extracellular Ca2+, and by phospholipase A2 inhibitor quinacrine (25 µM. Clofazimine further augmented the effect of Ca2+ ionophore ionomycin (0.1 µM on eryptosis. The clofazimine induced annexin-V-binding was, however, completely abrogated by combined Ca2+ removal and addition of quinacrine. Conclusion: Clofazimine stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect in part dependent on entry of extracellular Ca2+, paralleled by cellular energy depletion and sensitive to

Influence of some DNA-alkylating drugs on thermal stability, acid and osmotic resistance of the membrane of whole human erythrocytes and their ghosts.

Science.gov (United States)

Ivanov, I T; Gadjeva, V

2000-09-01

Human erythrocytes and their resealed ghosts were alkylated under identical conditions using three groups of alkylating antitumor agents: mustards, triazenes and chloroethyl nitrosoureas. Osmotic fragility, acid resistance and thermal stability of membranes were changed only in alkylated ghosts in proportion to the concentration of the alkylating agent. All the alkylating agents decreased acid resistance in ghosts. The clinically used drugs sarcolysine, dacarbazine and lomustine all decreased osmotic fragility and thermal stability of ghost membranes depending on their lipophilicity. DM-COOH did not decrease osmotic fragility and thermal stability of ghost membranes, while NEM increased thermal stability of membranes. The preliminary but not subsequent treatment of ghosts with DM-COOH fully abolished the alkylation-induced thermal labilization of ghost membrane proteins while NEM had a partial effect only. The present study gives direct evidence that alkylating agents, having a high therapeutic activity against malignant growth, bind covalently to proteins of cellular membranes.

Isolation of low-molecular-weight lead-binding protein from human erythrocytes

International Nuclear Information System (INIS)

Raghavan, S.R.V.; Gonick, H.C.

1977-01-01

In blood, lead is mainly associated with erythrocytes and only a very small amount is found in plasma. Previously it was thought that the lead was bound to the erythrocyte cell membrane but more recently it has been observed that lead is bound primarily to the cell contents, ostensibly hemoglobin. In examining the lead-binding properties of normal human erythrocytes and those of lead-exposed industrial workers, we have found that, whereas lead binds only to hemoglobin in normal erythrocytes, there is also appreciable binding of lead to a low-molecular weight-protein in erythrocytes from lead-exposed workers. The synthesis of this protein may be induced by lead exposure. The 10,000 molecular weight protein may act as a storage site and mechanism for segregating lead in a non-toxic form

The Uremic Toxin Acrolein Promotes Suicidal Erythrocyte Death

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Mohamed Siyabeldin E. Ahmed

2013-05-01

Full Text Available Background: Anemia is a major complication of end stage renal disease. The anemia is mainly the result of impaired formation of erythrocytes due to lack of erythropoietin and iron deficiency. Compelling evidence, however, points to the contribution of accelerated erythrocyte death, which decreases the life span of circulating erythrocytes. Erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine-exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i. Erythrocytes could be sensitized to cytosolic Ca2+ by ceramide. In end stage renal disease, eryptosis may possibly be stimulated by uremic toxins. The present study explored, whether the uremic toxin acrolein could trigger eryptosis. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin-V-binding, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, and ceramide from fluorescent antibodies. Results: A 48 h exposure to acrolein (30 － 50 µM did not significantly modify [Ca2+]i but significantly decreased forward scatter and increased annexin-V-binding. Acrolein further triggered slight, but significant hemolysis and increased ceramide formation in erythrocytes. Acrolein (50 µM induced annexin-V-binding was significantly blunted in the nominal absence of extracellular Ca2+. Acrolein augmented the annexin-V-binding following treatment with Ca2+ ionophore ionomycin (1 µM. Conclusion: Acrolein stimulates suicidal erythrocyte death or eryptosis, an effect at least in part due to stimulation of ceramide formation with subsequent sensitisation of the erythrocytes to cytosolic Ca2+.

Selective radiolabeling and isolation of the hydrophobic membrane-binding domain of human erythrocyte acetylcholinesterase

International Nuclear Information System (INIS)

Roberts, W.L.; Rosenberry, T.L.

1986-01-01

The hydrophobic, membrane-binding domain of purified human erythrocyte acetylcholinesterase was labeled with the photoactivated reagent 3-(trifluoromethyl)-3-(m-[ 125 I]iodophenyl)diazirine. The radiolabel was incorporated when the enzyme was prepared in detergent-free aggregates, in detergent micelles, or in phospholipid liposomes, but the highest percentage of labeling occurred in the detergent-free aggregates. Papain digestion of the enzyme released the hydrophobic domain, and polyacrylamide gel electrophoresis in sodium dodecyl sulfate or gel exclusion chromatography demonstrated that the label was localized exclusively in the cleaved hydrophobic domain fragment. This fragment was purified in a three-step procedure. Digestion was conducted with papain attached to Sepharose CL-4B, and the supernatant was adsorbed to acridinium affinity resin to remove the hydrophilic enzyme fragment. The nonretained fragment associated with Triton X-100 micelles was then chromatographed on Sepharose CL-6B, and finally detergent was removed by chromatography on Sephadex LH-60 in an ethanol-formic acid solvent. The fragment exhibited an apparent molecular weight of 3100 on the Sephadex LH-60 column when compared with peptide standards. However, amino acid analysis of the purified fragment revealed only 1 mol each of histidine and glycine per mole of fragment in contrast to the 25-30 mole of amino acids expected on the basis of the molecular weight estimate. This result suggests a novel non-amino acid structure for the hydrophobic domain of human erythrocyte acetylcholinesterase

The influence of split doses of γ-radiation on human erythrocytes

International Nuclear Information System (INIS)

Koziczak, R.; Gonciarz, M.; Krokosz, A.; Szweda-Lewandowska, Z.

2003-01-01

Human erythrocyte suspensions in an isotonic Na-phosphate buffer, pH 7.4, of hematocrit of 2% were exposed under air to gamma radiation at a dose rate of 2.2 kGy. Erythrocytes were irradiated with single doses, and identical doses split into two fractions with an interval time of 3.5 h between following exposures. The obtained results indicated that the irradiation of enucleated human erythrocytes with split doses caused a reduction of hemolysis (2.4 times), a decrease in the level of damage to membrane lipids and the contents of MetHb, compared with identical single doses. However, the splitting of radiation doses did not change the level of damage to the membrane proteins, as was estimated with a maleimide spin label. The obtained results suggest that a decrease in the level of damage to lipids was related to a decrease in hemolysis. (author)

Erratum Detergent-resistant membranes in human erythrocytes and ...

Indian Academy of Sciences (India)

Unknown

Figure 3. Immunodetection of flotillin-2 and band 3 in DRMs isolated from erythrocyte ghosts by various treatments. Flotillin-2. (left) and band 3 (right) Western blotting in ten fractions of 0⋅5 ml each, obtained from the sucrose gradients described in figure 2 and numbered from top to bottom. Flotillin-2 is enriched in DRMs ...

In vitro Plasmodium falciparum drug sensitivity assay: inhibition of parasite growth by incorporation of stomatocytogenic amphiphiles into the erythrocyte membrane

DEFF Research Database (Denmark)

Ziegler, Hanne L; Staerk, Dan; Christensen, Jette

2002-01-01

Lupeol, which shows in vitro inhibitory activity against Plasmodium falciparum 3D7 strain with a 50% inhibitory concentration (IC50) of 27.7 +/- 0.5 microM, was shown to cause a transformation of the human erythrocyte shape toward that of stomatocytes. Good correlation between the IC50 value...... culture continued to grow well in untreated erythrocytes. Thus, the antiplasmodial activity of lupeol appears to be indirect, being due to stomatocytic transformation of the host cell membrane and not to toxic effects via action on a drug target within the parasite. A number of amphiphiles that cause...... for development of new antimalarial drugs, care must be exercised in the interpretation of results of screening of plant extracts and natural product libraries by an in vitro Plasmodium toxicity assay....

Elevated 2,3-diphosphoglycerate concentrations and alteration of structural integrity in the erythrocytes of Indian cases of visceral leishmaniasis.

Science.gov (United States)

Biswas, T; Ghosh, D K; Mukherjee, N; Ghosal, J

1995-08-01

The visceral leishmaniasis (VL) known as kala-azar in India is characterized by severe anaemia. The anaemia seems to be the result, at least in part, of the relatively short life-time of the erythrocytes, which have weakened cell membranes, possibly because of elevated concentrations of 2,3-diphosphoglycerate (2,3-DPG). There is a negative correlation (r = 0.91; P < 0.01) between erythrocytic 2,3-DPG concentrations and the blood concentration of haemoglobin, and the erythrocytes from infected patients display higher osmotic fragility than those from uninfected controls. Spectrofluorometry, using 1,6-diphenyl 1,3,5-hexatriene as a probe, indicated that fluorescence depolarization and microviscosity are also higher in the erythrocytic membranes from VL cases than in those from the controls. The cholesterol/phospholipid ratio is also relatively high in the membranes from the VL cases and there is degradation of the skeletal components and the major integral protein (band 3). The enhanced concentration of 2,3-DPG may be related to the altered structural integrity of the erythrocytes and this may lead to anisocytosis and the reduction in the erythrocytic half life.

Hypo- and hypernatremia results in inaccurate erythrocyte mean corpuscular volume measurement in vitro, when using Sysmex XE 2100

DEFF Research Database (Denmark)

Phillipsen, Jens Peter; Madsen, Kirsten Vikkelsø

2015-01-01

INTRODUCTION: Automated hematology analyzers dilute patient erythrocytes with an isoosmotic diluent before quantitating the erythrocyte mean cell volume (MCV). However, if patient plasma osmolality differs from the diluent, water will cross the erythrocytes membrane and establish a new equilibrium...... across the membrane. Since the new equilibrium is reached before the measurement of the MCV, the measured MCV may not reflect the true MCV in vivo. AIM: Calculation of the theoretical change in MCV at changed P-Sodium/P-Osmolality and to investigate if the automated blood cell counter Sysmex XE 2100...

Inhibition by nucleosides of glucose-transport activity in human erythrocytes.

OpenAIRE

Jarvis, S M

1988-01-01

The interaction of nucleosides with the glucose carrier of human erythrocytes was examined by studying the effect of nucleosides on reversible cytochalasin B-binding activity and glucose transport. Adenosine, inosine and thymidine were more potent inhibitors of cytochalasin B binding to human erythrocyte membranes than was D-glucose [IC50 (concentration causing 50% inhibition) values of 10, 24, 28 and 38 mM respectively]. Moreover, low concentrations of thymidine and adenosine inhibited D-glu...

In vitro and ex vivo effect of hyaluronic acid on erythrocyte flow properties

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Palatnik S

2010-02-01

Full Text Available Abstract Background Hyaluronic acid (HA is present in many tissues; its presence in serum may be related to certain inflammatory conditions, tissue damage, sepsis, liver malfunction and some malignancies. In the present work, our goal was to investigate the significance of hyaluronic acid effect on erythrocyte flow properties. Therefore we performed in vitro experiments incubating red blood cells (RBCs with several HA concentrations. Afterwards, in order to corroborate the pathophysiological significance of the results obtained, we replicated the in vitro experiment with ex vivo RBCs from diagnosed rheumatoid arthritis (RA patients, a serum HA-increasing pathology. Methods Erythrocyte deformability (by filtration through nucleopore membranes and erythrocyte aggregability (EA were tested on blood from healthy donors additioned with purified HA. EA was measured by transmitted light and analyzed with a mathematical model yielding two parameters, the aggregation rate and the size of the aggregates. Conformational changes of cytoskeleton proteins were estimated by electron paramagnetic resonance spectroscopy (EPR. Results In vitro, erythrocytes treated with HA showed increased rigidity index (RI and reduced aggregability, situation strongly related to the rigidization of the membrane cytoskeleton triggered by HA, as shown by EPR results. Also, a significant correlation (r: 0.77, p Conclusions Our results lead us to postulate the hypothesis that HA interacts with the erythrocyte surface leading to modifications in erythrocyte rheological and flow properties, both ex vivo and in vitro.

Triggering of Suicidal Erythrocyte Death by Regorafenib

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Jens Zierle

2016-01-01

Full Text Available Background/Aims: The multikinase inhibitor regorafenib is utilized for the treatment of malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Side effects of regorafenib include anemia. At least in theory, regorafenib induced anemia could result from stimulated suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and ceramide. The present study explored, whether regorafenib induces eryptosis and, if so, whether it is effective up- and/or downstream of Ca2+. Methods: To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to regorafenib (≥ 0.5 µg/ml significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (≥ 1.25 µg/ml, but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of regorafenib on annexin-V-binding and forward scatter was not significantly blunted by removal of extracellular Ca2+. Regorafenib (5 µg/ml significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin. Conclusions: Regorafenib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+.

Triggering of Suicidal Erythrocyte Death by Regorafenib.

Science.gov (United States)

Zierle, Jens; Bissinger, Rosi; Bouguerra, Ghada; Abbès, Salem; Lang, Florian

2016-01-01

The multikinase inhibitor regorafenib is utilized for the treatment of malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Side effects of regorafenib include anemia. At least in theory, regorafenib induced anemia could result from stimulated suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study explored, whether regorafenib induces eryptosis and, if so, whether it is effective up- and/or downstream of Ca2+. To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. A 48 hours exposure of human erythrocytes to regorafenib (≥ 0.5 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (≥ 1.25 µg/ml), but did not significantly increase Fluo3-fluorescence, DCFDA fluorescence or ceramide abundance. The effect of regorafenib on annexin-V-binding and forward scatter was not significantly blunted by removal of extracellular Ca2+. Regorafenib (5 µg/ml) significantly augmented the increase of annexin-V-binding, but significantly blunted the decrease of forward scatter following treatment with the Ca2+ ionophore ionomycin. Regorafenib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part downstream of Ca2+. © 2016 The Author(s) Published by S. Karger AG, Basel.

Fucoxanthin Induced Suicidal Death of Human Erythrocytes

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Marilena Briglia

2015-12-01

Full Text Available Background/Aims: Fucoxanthin, a carotenoid isolated from brown seaweeds, induces suicidal death or apoptosis of tumor cells and is thus considered for the treatment or prevention of malignancy. In analogy to apoptosis of nucleated cell, erythrocytes may enter eryptosis, the suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and activation of p38 kinase or protein kinase C. The present study explored, whether and how fucoxanthin induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, and abundance of reactive oxygen species (ROS from DCFDA dependent fluorescence and lipid peroxidation using BODIPY fluoresence. Results: A 48 hours exposure of human erythrocytes to fucoxanthin significantly increased the percentage of annexin-V-binding cells (≥ 50 µM, significantly decreased average forward scatter (≥ 25 µM, significantly increased hemolysis (≥ 25 µM, significantly increased Fluo3-fluorescence (≥ 50 µM, significantly increased lipid peroxidation, but did not significantly modify DCFDA fluorescence. The effect of fucoxanthin on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+, and was insensitive to p38 kinase inhibitor skepinone (2 µM and to protein kinase C inhibitor calphostin (100 nM. Conclusion: Fucoxanthin triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of Ca2+ entry.

Stimulation of Suicidal Erythrocyte Death by Garcinol

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Antonella Fazio

2015-09-01

Full Text Available Background/Aims: The benzophenone garcinol from dried fruit rind of Garcinia indica counteracts malignancy, an effect at least in part due to stimulation of apoptosis. The proapototic effect of garcinol is attributed in part to inhibition of histone acetyltransferases and thus modification of gene expression. Moreover, garcinol triggers mitochondrial depolarisation. Erythrocytes lack gene expression and mitochondria but are nevertheless able to enter apoptosis-like suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, energy depletion and Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i. The present study explored, whether and how garcinol induces eryptosis. Methods: To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence and cytosolic ATP levels utilizing a luciferin-luciferase-based assay. Results: A 24 hours exposure of human erythrocytes to garcinol (2.5 or 5 µM significantly increased the percentage of annexin-V-binding cells. Garcinol decreased (at 1 µM and 2.5 µM or increased (at 5 µM forward scatter. Garcinol (5 µM further increased Fluo3-fluorescence, increased DCFDA fluorescence, and decreased cytosolic ATP levels. The effect of garcinol on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. Conclusions: Garcinol triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of ROS formation, energy depletion and Ca2+ entry.

Electron Pathways through Erythrocyte Plasma Membrane in Human Physiology and Pathology: Potential Redox Biomarker?

OpenAIRE

Matteucci, Elena; Giampietro, Ottavio

2007-01-01

Erythrocytes are involved in the transport of oxygen and carbon dioxide in the body. Since pH is the influential factor in the Bohr-Haldane effect, pHi is actively maintained via secondary active transports Na+/H+ exchange and HC3 -/Cl- anion exchanger. Because of the redox properties of the iron, hemoglobin generates reactive oxygen species and thus, the human erythrocyte is constantly exposed to oxidative damage. Although the adult erythrocyte lacks protein synthesis and cannot restore dama...

Induction of lipid peroxidation in erythrocytes during cholesterol oxidation catalyzed by cholesterol oxidase

International Nuclear Information System (INIS)

Kagan, V.E.; Monovich, O.; Ribarov, S.R.

1986-01-01

The authors study the ability of cholesterol oxidase (ChO), which catalyzes oxidation of cholesterol (Ch) to cholest-4-en-3-one and, at the same time, reduction of O 2 to H 2 O 2 , to induce the lipid peroxidation (LPO) in plasma membranes. Erythrocyte ghosts were obtained from guinea pig blood; the reaction of oxidation of Ch in the erythrocyte ghosts or in micelles with Triton X-100 was carried out in the following medium: Tris-HCl 0.2 M, pH 7.0 (at 37 C), Triton X-100 0.25%, and ChO 0.05 U/ml. At the present time ChO is often used to study the asymmetry of distribution of Ch in biomembranes and the velocity of its transbilayer migration. It is suggested that changes in membrane permeability do not take place during the reaction catalyzed by the enzyme, and no products capable of affecting flip-flop in biological are formed. Accumulation of LPO products in erythrocyte membranes discovered in this investigation under the influence of ChO compels critical re-examination of the resutls

Phenotypic variations in osmotic lysis of Sahel goat erythrocytes in non-ionic glucose media.

Science.gov (United States)

Igbokwe, Nanacha Afifi; Igbokwe, Ikechukwu Onyebuchi

2016-03-01

Erythrocyte osmotic lysis in deionised glucose media is regulated by glucose influx, cation efflux, and changes in cell volume after water diffusion. Transmembrane fluxes may be affected by varied expression of glucose transporter protein and susceptibility of membrane proteins to glucose-induced glycosylation and oxidation in various physiologic states. Variations in haemolysis of Sahel goat erythrocytes after incubation in hyposmotic non-ionic glucose media, associated with sex, age, late pregnancy, and lactation, were investigated. The osmotic fragility curve in glucose media was sigmoidal with erythrocytes from goats in late pregnancy (PRE) or lactation (LAC) or from kid (KGT) or middle-aged (MGT) goats. Non-sigmoidal phenotype occurred in yearlings (YGT) and old (OGT) goats. The composite fragility phenotype for males and non-pregnant dry (NPD) females was non-sigmoidal. Erythrocytes with non-sigmoidal curves were more stable than those with sigmoidal curves because of inflectional shift of the curve to the left. Erythrocytes tended to be more fragile with male than female sex, KGT and MGT than YGT and OGT, and LAC and PRE than NPD. Thus, sex, age, pregnancy, and lactation affected the haemolytic pattern of goat erythrocytes in glucose media. The physiologic state of the goat affected the in vitro interaction of glucose with erythrocytes, causing variations in osmotic stability with variants of fragility phenotype. Variations in the effect of high extracellular glucose concentrations on the functions of membrane-associated glucose transporter, aquaporins, and the cation cotransporter were presumed to be relevant in regulating the physical properties of goat erythrocytes under osmotic stress.

Tirilazad mesylate protects stored erythrocytes against osmotic fragility.

Science.gov (United States)

Epps, D E; Knechtel, T J; Bacznskyj, O; Decker, D; Guido, D M; Buxser, S E; Mathews, W R; Buffenbarger, S L; Lutzke, B S; McCall, J M

1994-12-01

The hypoosmotic lysis curve of freshly collected human erythrocytes is consistent with a single Gaussian error function with a mean of 46.5 +/- 0.25 mM NaCl and a standard deviation of 5.0 +/- 0.4 mM NaCl. After extended storage of RBCs under standard blood bank conditions the lysis curve conforms to the sum of two error functions instead of a possible shift in the mean and a broadening of a single error function. Thus, two distinct sub-populations with different fragilities are present instead of a single, broadly distributed population. One population is identical to the freshly collected erythrocytes, whereas the other population consists of osmotically fragile cells. The rate of generation of the new, osmotically fragile, population of cells was used to probe the hypothesis that lipid peroxidation is responsible for the induction of membrane fragility. If it is so, then the antioxidant, tirilazad mesylate (U-74,006f), should protect against this degradation of stored erythrocytes. We found that tirilazad mesylate, at 17 microM (1.5 mol% with respect to membrane lecithin), retards significantly the formation of the osmotically fragile RBCs. Concomitantly, the concentration of free hemoglobin which accumulates during storage is markedly reduced by the drug. Since the presence of the drug also decreases the amount of F2-isoprostanes formed during the storage period, an antioxidant mechanism must be operative. These results demonstrate that tirilazad mesylate significantly decreases the number of fragile erythrocytes formed during storage in the blood bank.

Effect of Sodium Fluoride Ingestion on Malondialdehyde Concentration and the Activity of Antioxidant Enzymes in Rat Erythrocytes

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José A. Morales-González

2010-06-01

Full Text Available Fluoride intoxication has been shown to produce diverse deleterious metabolic alterations within the cell. To determine the effects of sodium fluoride (NaF treatment on malondialdehyde (MDA levels and on the activity of antioxidant enzymes in rat erythrocytes, Male Wistar rats were treated with 50 ppm of NaF or were untreated as controls. Erythrocytes were obtained from rats sacrificed weekly for up to eight weeks and the concentration of MDA in erythrocyte membrane was determined. In addition, the activity of the enzymes superoxide, dismutase, catalase, and glutathione peroxidase were determined. Treatment with NaF produces an increase in the concentration of malondialdehyde in the erythrocyte membrane only after the eight weeks of treatment. On the other hand, antioxidant enzyme activity was observed to increase after the fourth week of NaF treatment. In conclusion, intake of NaF produces alterations in the erythrocyte of the male rat, which indicates induction of oxidative stress.

Erythrocytes L-arginine y+ transporter inhibition by N-ethylmaleimide in ice-bath.

Science.gov (United States)

Pinheiro da Costa, Bartira Ercília; de Almeida, Priscilla Barcellos; Conceição, Ioná Rosine; Antonello, Ivan Carlos Ferreira; d'Avila, Domingos O; Poli-de-Figueiredo, Carlos Eduardo

2010-11-01

Erythrocytes L: -arginine uptake is conveyed by y+ and y+L membrane transport systems. Pre-incubation with N-ethylmaleimide for 10 min at 37°C inhibits the y+ system. The aim of this study was to determine the ideal pre-incubation temperature in evaluating y+ and y+L systems. Cells were pre-incubated with or without N-ethylmaleimide for 10 min at 4°C and 37°C. L: -Arginine uptake was quantified by radioisotope and standard erythrocytes membrane flux methodology. Results demonstrate that erythrocytes L: -arginine content is depleted by pre-incubation at 37°C for 10 min, thus changing the V (max) measurement. The inhibitory effect of N-ethylmaleimide pre-incubation was temperature independent and already complete after 1 min of incubation. No significant difference in kinetic parameters was detected between cells pre-incubated at 37°C or 4°C, under zero-trans conditions. In conclusion, we suggest that measurement of erythrocytes L: -arginine uptake by y+ and y+L systems could be carried out without N-ethylmaleimide pre-incubation at 37°C.

The effects of beta-carotene and vitamin E on erythrocytes lipid peroxidation in beta-thalassemia patients

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Soleiman Mahjoub

2007-12-01

Full Text Available BACKGROUND: Thalassemia is the most common hereditary disease in the world. Thalassemic erythrocytes are exposed to higher oxidative stress and lipid peroxidation. The aim of this study was to investigate the effects of beta-carotene and vitamin E on erythrocytes lipid peroxidation in beta-thalassemia patients.
METHODS: A prospective double-blind, placebo-controlled study of the effect of beta-carotene and vitamin E on lipid peroxidation in erythrocytes membranes was performed on 120 beta-thalassemia major patients in four groups. The patients were supplemented for 4 weeks as follows: group 1 with beta-carotene (13 mg/day, group 2 with vitamin E (550 mg/day, group 3 with beta-carotene plus vitamin E and group 4 with placebo. We prepared all capsules for 4 roups in the same shape and color. Measurements of serum beta-carotene and vitamin E were performed by high performance
liquid chromatography. After preparation of ghost cells from blood specimens, malondialdehyde (MDA was determined as index of lipid peroxidation in erythrocytes membranes before and after treatment. RESULTS: The levels of serum beta-carotene and vitamin E were significantly lower and MDA concentrations in erythrocytes membranes were significantly higher in beta-thalassemia patients compared to controls (P<0.001. In groups that treated with vitamin supplements for 4-weeks, lipid peroxidation rates were significantly reduced after treatment (P<0.001, but in placebo group there was not significant difference (P>0.05.
CONCLUSIONS: Our findings provide evidence that an oral treatment with beta-carotene and vitamin E can significantly reduce lipid peroxidation of erythrocytes membranes and could be useful in management of beta-thalassemia major patients. KEYWORDS: Beta-thalassemia major, beta-carotene, vitamin E, malondialdehyde, lipid peroxidation.

Functional State of Rat’s Erythrocytes Under Different Stress Conditions

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A.A. Martusevich

2016-08-01

Full Text Available Background: In our early publications was shown that electrophorhetic motility of erythrocytes (EPME is a high effective criteria of adaptation response. This correlation is based on parallel development of adaptation syndrome and activation of the main organism regulatory systems, such as sympatoadrenalic and hypotalamo-hypophosial-adrenal ones. Objective: study of the influence of physical exercises and adrenaline injections on electrophorhetic motility, membrahes phospholipids spectrum and oxidative metabolism of the rats’ erythrocytes. Methods: Rats were divided into three equal groups. First group of animals was control (n=10; without any manipulations. Rats of second group were subjected to physical load in the form of a sailing duration of 15 minutes with a cargo amounting to 10% of animal body weight (water temperature – 26-280C. Rats of third group were intraperitoneally injected with adrenaline hydrochloride (0.1 mg/kg. Blood sampling was made from the sublingual vein in 15, 30, 60, 120 minutes and 24 hours after exposure. We estimated the dynamics of the electrophorhetic motility of erythrocytes (EPME, the phospholipid spectrum of erythrocytes membranes, the concentration of malonic dialdehyde (MDA and the state of the glutathione system. Results and conclusions: The study suggests that red blood cell as a biological system is capable for realization of stress response may develop a special “alarm reaction” after action of the stress agent. This response initiates activation of free radical processes and phospholipids profile in erythrocyte membranes with reducing of its electronegativity. This stage enhances the activity of the antioxidant system, is limiting the development of lipid peroxidation processes, and leads to the development of "adaptation stage" of the cellular system, coupled with the restoration of the electronegativity of the membrane and the mobilization of reserves of low molecular antioxidants, particularly

Inositol phosphates influence the membrane bound Ca2+/Mg2+ stimulated ATPase from human erythrocyte membranes

International Nuclear Information System (INIS)

Kester, M.; Ekholm, J.; Kumar, R.; Hanahan, D.J.

1986-01-01

The modulation by exogenous inositol phosphates of the membrane Ca 2+ /Mg 2+ ATPase from saponin/EGTA lysed human erythrocytes was determined in a buffer (pH 7.6) containing histidine, 80 mM, MgCl 2 , 3.3 mM, NaCl, 74 mM, KCl, 30 mM, Na 2 ATP, 2.3 mM, ouabain, 0.83 mM, with variable amounts of CaCl 2 and EGTA. The ATPase assay was linear with time at 44 0 C. The inositol phosphates were commercially obtained and were also prepared from 32 P labeled rabbit platelet inositol phospholipids. Inositol triphosphate (IP 3 ) elevated the Ca 2+ /Mg 2+ ATPase activity over basal levels in a dose, time, and calcium dependent manner and were increased up to 85% of control values. Activities for the Na + /K + -ATPase and a Mg 2+ ATPase were not effected by IP 3 . Ca 2+ /Mg 2+ APTase activity with IP 2 or IP 3 could be synergistically elevated with calmodulin addition. The activation of the ATPase with IP 3 was calcium dependent in a range from .001 to .02 mM. The apparent Km and Vmax values were determined for IP 3 stimulated Ca 2+ /Mg 2+ ATPase

Evidence for in vitro and in vivo expression of the conserved VAR3 (type 3) plasmodium falciparum erythrocyte membrane protein 1

DEFF Research Database (Denmark)

Wang, Christian W; Lavstsen, Thomas; Bengtsson, Dominique C

2012-01-01

ABSTRACT: BACKGROUND: Members of the Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) adhesion antigen family are major contributors to the pathogenesis of P. falciparum malaria infections. The PfEMP1-encoding var genes are among the most diverse sequences in nature, but three genes......, var1, var2csa and var3 are found conserved in most parasite genomes. The most severe forms of malaria disease are caused by parasites expressing a subset of antigenically conserved PfEMP1 variants. Thus the ubiquitous and conserved VAR3 PfEMP1 is of particular interest to the research field. Evidence...... of VAR3 expression on the infected erythrocyte surface has never been presented, and var3 genes have been proposed to be transcribed and expressed differently from the rest of the var gene family members. METHODS: In this study, parasites expressing VAR3 PfEMP1 were generated using anti-VAR3 antibodies...

Erythrocytes in muscular dystrophy. Investigation with 31P nuclear magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

1981-01-01

Phosphorus 31 nuclear magnetic resonance ( 31 P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual 31 P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which leads to lower steady-state concentrations of the intracellular phosphates

Erythrocytes in muscular dystrophy. Investigation with 31P nuclear magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Sarpel, G.; Lubansky, H.J.; Danon, M.J.; Omachi, A.

1981-01-01

Phosphorus 31 nuclear magnetic resonance (31P NMR) signals were recorded from intact human erythrocytes for 16 hours. Total phosphate concentration, which was estimated as the sum of the individual 31P signals, was 25% lower in erythrocytes from men with myotonic dystrophy than in control erythrocytes. The inorganic-phosphate fraction contained the highest average phosphate concentration over the 16-hour period, and made the major contribution to the difference in total phosphate between the two groups. This result was not observed in erythrocytes from either women with myotonic dystrophy or patients with Duchenne's dystrophy and may be due to a change in cell membrane permeability to inorganic phosphate, which lead to lower steady-state concentrations of the intracellular phosphates

Transcriptomic Analysis of Young and Old Erythrocytes of Fish

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Miriam Götting

2017-12-01

Full Text Available Understanding gene expression changes over the lifespan of cells is of fundamental interest and gives important insights into processes related to maturation and aging. This study was undertaken to understand the global transcriptome changes associated with aging in fish erythrocytes. Fish erythrocytes retain their nuclei throughout their lifetime and they are transcriptionally and translationally active. However, they lose important functions during their lifespan in the circulation. We separated rainbow trout (Oncorhynchus mykiss erythrocytes into young and old fractions using fixed angle-centrifugation and analyzed transcriptome changes using RNA sequencing (RNA-seq technology and quantitative real-time PCR. We found 930 differentially expressed between young and old erythrocyte fractions; 889 of these showed higher transcript levels in young, while only 34 protein-coding genes had higher transcript levels in old erythrocytes. In particular genes involved in ion binding, signal transduction, membrane transport, and those encoding various enzyme classes are affected in old erythrocytes. The transcripts with higher levels in old erythrocytes were associated with seven different GO terms within biological processes and nine within molecular functions and cellular components, respectively. Our study furthermore found several highly abundant transcripts as well as a number of differentially expressed genes (DEGs for which the protein products are currently not known revealing the gaps of knowledge in most non-mammalian vertebrates. Our data provide the first insight into changes involved in aging on the transcriptional level and thus opens new perspectives for the study of maturation processes in fish erythrocytes.

Erythrocyte-like hollow carbon capsules and their application in proton exchange membrane fuel cells.

Science.gov (United States)

Kim, Jung Ho; Yu, Jong-Sung

2010-12-14

Hierarchical nanostructured erythrocyte-like hollow carbon (EHC) with a hollow hemispherical macroporous core of ca. 230 nm in diameter and 30-40 nm thick mesoporous shell was synthesized and explored as a cathode catalyst support in a proton exchange membrane fuel cell (PEMFC). The morphology control of EHC was successfully achieved using solid core/mesoporous shell (SCMS) silica template and different styrene/furfuryl alcohol mixture compositions by a nanocasting method. The EHC-supported Pt (20 wt%) cathodes prepared have demonstrated markedly enhanced catalytic activity towards oxygen reduction reactions (ORRs) and greatly improved PEMFC polarization performance compared to carbon black Vulcan XC-72 (VC)-supported ones, probably due to the superb structural characteristics of the EHC such as uniform size, well-developed porosity, large specific surface area and pore volume. In particular, Pt/EHC cathodes exhibited ca. 30-60% higher ORR activity than a commercial Johnson Matthey Pt catalyst at a low catalyst loading of 0.2 mg Pt cm(-2).

Enzymatic methylation of band 3 anion transporter in intact human erythrocytes

International Nuclear Information System (INIS)

Lou, L.L.; Clarke, S.

1987-01-01

Band 3, the anion transport protein of erythrocyte membranes, is a major methyl-accepting substrate of the intracellular erythrocyte protein carboxyl methyltransferase (S-adenosyl-L-methionine: protein-D-aspartate O-methyltransferase; EC 2.1.1.77). The localization of methylation sites in intact cells by analysis of proteolytic fragments indicated that sites were present in the cytoplasmic N-terminal domain as well as the membranous C-terminal portion of the polypeptide. The amino acid residues that serve as carboxyl methylation sites of the erythrocyte anion transporter were also investigated. 3 H-Methylated band 3 was purified from intact erythrocytes incubated with L-[methyl- 3 H]methionine and from trypsinized and lysed erythrocytes incubated with S-adenosyl-L-[methyl- 3 H]methionine. After proteolytic digestion with carboxypeptidase Y, D-aspartic acid beta-[ 3 H]methyl ester was isolated in low yields (9% and 1%, respectively) from each preparation. The bulk of the radioactivity was recovered as [ 3 H]methanol, and the amino acid residue(s) originally associated with these methyl groups could not be determined. No L-aspartic acid beta-[ 3 H]methyl ester or glutamyl gamma-[ 3 H]methyl ester was detected. The formation of D-aspartic acid beta-[ 3 H]methyl esters in this protein in intact cells resulted from protein carboxyl methyltransferase activity since it was inhibited by adenosine and homocysteine thiolactone, which increases the intracellular concentration of the potent product inhibitor S-adenosylhomocysteine, and cycloleucine, which prevents the formation of the substrate S-adenosyl-L-[methyl- 3 H]methionine

Triggering of Suicidal Erythrocyte Death Following Boswellic Acid Exposure

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Salvatrice Calabrò

2015-08-01

Full Text Available Background/Aims: The antinflammatory natural product boswellic acid is effective against cancer at least in part by inducing tumor cell apoptosis. Similar to apoptosis of nucleated cells erythrocytes may enter eryptosis, a suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, increase of cytosolic Ca2+-activity ([Ca2+]i, energy depletion, ceramide formation and p38 kinase activation. The present study tested, whether and how boswellic acid induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca2+]i from Fluo3-fluorescence, ceramide abundance utilizing specific antibodies, reactive oxygen species (ROS from 2′,7′-dichlorodihydrofuorescein diacetate (DCFDA fluorescence, and cytosolic ATP concentration utilizing a luciferin-luciferase assay kit. Results: A 24 hours exposure of human erythrocytes to boswellic acid (5 µg/ml significantly increased the percentage of annexin-V-binding cells (to 9.3 ±0.9 % and significantly decreased forward scatter. Boswellic acid did not significantly modify [Ca2+]i, cytosolic ATP, ROS, or ceramide abundance. The effect of boswellic acid on annexin-V-binding was significantly blunted, but not abolished by p38 kinase inhibitors skepinone (2 µM and SB203580 (2 µM. Conclusions: Boswellic acid stimulates cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part dependent on p38 protein kinase activity.

Adhesion of Plasmodium falciparum infected erythrocytes in ex vivo perfused placental tissue

DEFF Research Database (Denmark)

Pehrson, Caroline; Mathiesen, Line; Heno, Kristine K

2016-01-01

placental tissue. RESULTS: The ex vivo placental perfusion model was modified to study adhesion of infected erythrocytes binding to CSA, endothelial protein C receptor (EPCR) or a transgenic parasite where P. falciparum erythrocyte membrane protein 1 expression had been shut down. Infected erythrocytes......, such as binding to immunoglobulins. Furthermore, other parasite antigens have been associated with placental malaria. These findings have important implications for placental malaria vaccine design. The objective of this study was to adapt and describe a biologically relevant model of parasite adhesion in intact...... expressing VAR2CSA accumulated in perfused placental tissue whereas the EPCR binding and the transgenic parasite did not. Soluble CSA and antibodies specific against VAR2CSA inhibited binding of infected erythrocytes. CONCLUSION: The ex vivo model provides a novel way of studying receptor-ligand interactions...

Early gametocytes of the malaria parasite Plasmodium falciparum specifically remodel the adhesive properties of infected erythrocyte surface

DEFF Research Database (Denmark)

Tibúrcio, Marta; Silvestrini, Francesco; Bertuccini, Lucia

2013-01-01

to ultrastructurally and biochemically analyse parasite-induced modifications on the red blood cell surface and to measure their functional consequences on adhesion to human endothelial cells. This work revealed that stage I gametocytes are able to deform the infected erythrocytes like asexual parasites, but do...... not modify its surface with adhesive 'knob' structures and associated proteins. Reduced levels of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) adhesins are exposed on the red blood cell surface bythese parasites, and the expression of the var gene family, which encodes 50-60 variants of PfEMP1......In Plasmodium falciparum infections the parasite transmission stages, the gametocytes, mature in 10 days sequestered in internal organs. Recent studies suggest that cell mechanical properties rather than adhesive interactions play a role in sequestration during gametocyte maturation. It remains...

Role of aminotransferases in glutamate metabolism of human erythrocytes

Energy Technology Data Exchange (ETDEWEB)

Ellinger, James J. [University of Wisconsin-Madison, Department of Biochemistry (United States); Lewis, Ian A. [Princeton University, Lewis-Sigler Institute for Integrative Genomics (United States); Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, Department of Biochemistry (United States)

2011-04-15

Human erythrocytes require a continual supply of glutamate to support glutathione synthesis, but are unable to transport this amino acid across their cell membrane. Consequently, erythrocytes rely on de novo glutamate biosynthesis from {alpha}-ketoglutarate and glutamine to maintain intracellular levels of glutamate. Erythrocytic glutamate biosynthesis is catalyzed by three enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamine aminohydrolase (GA). Although the presence of these enzymes in RBCs has been well documented, the relative contributions of each pathway have not been established. Understanding the relative contributions of each biosynthetic pathway is critical for designing effective therapies for sickle cell disease, hemolytic anemia, pulmonary hypertension, and other glutathione-related disorders. In this study, we use multidimensional {sup 1}H-{sup 13}C nuclear magnetic resonance (NMR) spectroscopy and multiple reaction mode mass spectrometry (MRM-MS) to measure the kinetics of de novo glutamate biosynthesis via AST, ALT, and GA in intact cells and RBC lysates. We show that up to 89% of the erythrocyte glutamate pool can be derived from ALT and that ALT-derived glutamate is subsequently used for glutathione synthesis.

Band 3 Erythrocyte Membrane Protein Acts as Redox Stress Sensor Leading to Its Phosphorylation by p72 Syk

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Antonella Pantaleo

2016-01-01

Full Text Available In erythrocytes, the regulation of the redox sensitive Tyr phosphorylation of band 3 and its functions are still partially defined. A role of band 3 oxidation in regulating its own phosphorylation has been previously suggested. The current study provides evidences to support this hypothesis: (i in intact erythrocytes, at 2 mM concentration of GSH, band 3 oxidation, and phosphorylation, Syk translocation to the membrane and Syk phosphorylation responded to the same micromolar concentrations of oxidants showing identical temporal variations; (ii the Cys residues located in the band 3 cytoplasmic domain are 20-fold more reactive than GSH; (iii disulfide linked band 3 cytoplasmic domain docks Syk kinase; (iv protein Tyr phosphatases are poorly inhibited at oxidant concentrations leading to massive band 3 oxidation and phosphorylation. We also observed that hemichromes binding to band 3 determined its irreversible oxidation and phosphorylation, progressive hemolysis, and serine hyperphosphorylation of different cytoskeleton proteins. Syk inhibitor suppressed the phosphorylation of band 3 also preventing serine phosphorylation changes and hemolysis. Our data suggest that band 3 acts as redox sensor regulating its own phosphorylation and that hemichromes leading to the protracted phosphorylation of band 3 may trigger a cascade of events finally leading to hemolysis.

Stimulation of ceramide formation and suicidal erythrocyte death by vitamin K(3) (menadione).

Science.gov (United States)

Qadri, Syed M; Eberhard, Matthias; Mahmud, Hasan; Föller, Michael; Lang, Florian

2009-11-25

Vitamin K(3) is an essential micronutrient required for the activation of coagulation factors and thus hemostasis. Administration of vitamin K(3) analogues may cause anemia, which at least in theory could be due to stimulation of suicidal erythrocyte death or eryptosis characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane leading to exposure of phosphatidylserine at the erythrocyte surface. Eryptosis is triggered by an increase in the cytosolic Ca(2+) activity, by ceramide and by energy depletion (decrease of cytosolic ATP). The present experiments explored, whether vitamin K(3) may influence eryptosis. Hemolysis was estimated from the supernatant hemoglobin concentration, phosphatidylserine-exposing erythrocytes from annexin V-binding in fluorescence-activated cell sorter (FACS) analysis, erythrocyte volume from forward scatter in FACS analysis, ceramide formation from binding of fluorescent antibodies, and erythrocyte ATP content from a luciferin-luciferase assay. As a result, vitamin K(3) (> or =1microM) caused lysis of an only small fraction of erythrocytes, but significantly increased ceramide formation, significantly increased the percentage of annexin V-binding erythrocytes, significantly decreased forward scatter and, at higher concentrations, significantly decreased the cellular ATP content. In conclusion, vitamin K(3) stimulates suicidal erythrocyte death, an effect at least partially due to ceramide formation and ATP depletion.

Radiation-induced structural changes in membrane proteins of human erythrocytes and ghosts and the relation to cellular morphology

Energy Technology Data Exchange (ETDEWEB)

Schuurhuis, G.J.; Hommes, J.; Vos, J.; Molenaar, I.; Konings, A.W.T. (Rijksuniversiteit Groningen (Netherlands))

1984-02-01

Isolated human erythrocytes and ghosts were irradiated with X-rays under different experimental conditions and the effect examined with regard to the structure of membrane proteins and morphology of whole cells and ghosts. From sodium dodecyl sulphate/polyacrylamide gel electrophoresis it is concluded that spectrin (band 1 and 2) is the most radiosensitive of the membrane proteins examined. X-irradiation of cells and ghosts induced covalent cross-linking of a small fraction of membrane proteins. In the protein aggregates thus formed spectrin was found to be the major component. Molecular disulphide (-SS-) bridges seemed to account for part of the cross-links observed. Some nondisulphide cross-links were found, especially when ghosts were irradiated. Significant amounts of spectrin aggregates were formed during post-irradiation incubation at 37/sup 0/C but not at 4/sup 0/C. In the intact cell a transformation in shape from discocyte to echinocyte accompanied the process of post-irradiation spectrin aggregation. The characteristics of both processes, such as their reversibility with adenosine, point to a metabolic involvement. It is shown that there is no causal relationship between the two phenomena observed. Possible causes of the post-irradiation effects and the parallelism with similar processes in non-irradiated metabolically depleted cells are discussed.

Radiation-induced structural changes in membrane proteins of human erythrocytes and ghosts and the relation to cellular morphology

International Nuclear Information System (INIS)

Schuurhuis, G.J.; Hommes, J.; Vos, J.; Molenaar, I.; Konings, A.W.T.

1984-01-01

Isolated human erythrocytes and ghosts were irradiated with X-rays under different experimental conditions and the effect examined with regard to the structure of membrane proteins and morphology of whole cells and ghosts. From sodium dodecyl sulphate/polyacrylamide gel electrophoresis it is concluded that spectrin (band 1 and 2) is the most radiosensitive of the membrane proteins examined. X-irradiation of cells and ghosts induced covalent cross-linking of a small fraction of membrane proteins. In the protein aggregates thus formed spectrin was found to be the major component. Molecular disulphide (-SS-) bridges seemed to account for part of the cross-links observed. Some nondisulphide cross-links were found, especially when ghosts were irradiated. Significant amounts of spectrin aggregates were formed during post-irradiation incubation at 37 0 C but not at 4 0 C. In the intact cell a transformation in shape from discocyte to echinocyte accompanied the process of post-irradiation spectrin aggregation. The characteristics of both processes, such as their reversibility with adenosine, point to a metabolic involvement. It is shown that there is no causal relationship between the two phenomena observed. Possible causes of the post-irradiation effects and the parallelism with similar processes in non-irradiated metabolically depleted cells are discussed. (author)

Bilayer/cytoskeleton interactions in lipid-symmetric erythrocytes assessed by a photoactivable phospholipid analogue

International Nuclear Information System (INIS)

Pradhan, D.; Schlegel, R.A.; Williamson, P.

1991-01-01

Two mechanisms have been proposed for maintenance of transbilayer phospholipid asymmetry in the erythrocyte plasma membrane, one involving specific interactions between the aminophospholipids of the inner leaflet of the bilayer and the cytoskeleton, particularly spectrin, and the other involving the aminophospholipid translocase. If the former mechanism is correct, then erythrocytes which have lost their asymmetric distribution of phospholipids should display altered bilayer/cytoskeleton interactions. To test this possibility, normal erythrocytes, erythrocytes from patients with chronic myelogenous leukemia or sickle disease, and lipid-symmetric and -asymmetric erythrocyte ghosts were labeled with the radioactive photoactivable analogue of phosphatidylethanolamine, 2-(2-azido-4-nitrobenzoyl)-1-acyl-sn-glycero-3-phospho[ 14 C] ethanolamine ([ 14 C]AzPE), previously shown to label cytoskeletal proteins from the bilayer. The labeling pattern of cytoskeletal proteins in pathologic erythrocytes and lipid-asymmetric erythrocyte ghosts was indistinguishable from normal erythrocytes, indicating that the probe detects no differences in bilayer/cytoskeleton interactions in these cells. In contrast, in lipid-symmetric erythrocyte ghosts, labeling of bands 4.1 and 4.2 and actin, and to a lesser extent ankyrin, by [ 14 C]AzPE was considerably reduced. Significantly, however, labeling of spectrin was unaltered in the lipid-symmetric cells. These results do not support a model in which spectrin is involved in the maintenance of an asymmetric distribution of phospholipids in erythrocytes

Does the chocolate interfere with the radiolabelling of erythrocytes with 99 mTc?; Le chocolat interfere-t-il avec le radiomarquage des erythrocytes au 99 mTc?

Energy Technology Data Exchange (ETDEWEB)

Bustani, H.; Colavolpe, C.; Imbert-Joscht, I.; Moubarik, C.; Havlik, P.; Pisano, P.; Guillet, B. [Service de medecine nucleaire, CHU Nord, Marseille, (France)

2009-05-15

We present in this work the case of a failure of erythrocytes labelling with {sup 99m}Tc for a twenty five years old patient making the examination not interpretable. The patient reported that she drank a chocolate drink the morning before the examination. it is the first observation of a such interaction between the chocolate consumption. We do not have any explanation at this date, some compounds in the cocoa can be considered with caution. Some flavonoids (catechins and pro-cyanidins) modify the plasmatic and intra-erythrocyte oxido-reducer statute and could interact with the labelling (specific reduction of the {sup 99m}Tc pertechnetate in the middle of erythrocyte by the tin pyrophosphate. These compounds, as well as the methyl-xanthine-theobromine, seem modify the membrane permeability of erythrocytes and could interfere with the input of pyrophosphate or {sup 99m}Tc-pertechnetate in the middle of erythrocyte. these observations, in spite of preliminary ones, lead us to recommend near the patients to avoid the chocolate foods in the twenty four hours before this type of examinations. (N.C.)

Erythrocyte endogenous proteinase activity during blood bank storage.

Science.gov (United States)

de Angelis, V; de Matteis, M C; Orazi, B M; Santarossa, L; Della Toffola, L; Raineri, A; Vettore, L

1990-01-01

We studied proteolytic alterations of membrane proteins in ghosts derived from human red blood cells, preserved up to 35 days in the liquid state either as whole blood or with additive solution. The study was carried out by performing sodium dodecyl sulfate polyacrylamide gel electrophoresis of stromal proteins from erythrocytes, either previously treated with proteinase inhibitors or previously incubated in conditions promoting proteolysis. To differentiate the effect of erythrocyte from granulocyte proteinases, the investigation was also carried out in leukocyte-free red cell preparations. The results show: (1) the effects of endogenous proteinases on membrane proteins derived from red cells stored under blood bank conditions; (2) a decrease of proteolytic effects in ghosts derived from red cells which have been submitted to a longer storage; (3) a relevant influence of the red cell resuspending medium before lysis on the time-dependent onset and exhaustion of proteolysis in ghosts. The presence of increased proteolysis in ghosts could be regarded as a marker of molecular lesions induced in red cells by storage under blood bank conditions.

Temperature-dependent binding of cyclosporine to an erythrocyte protein

International Nuclear Information System (INIS)

Agarwal, R.P.; Threatte, G.A.; McPherson, R.A.

1987-01-01

In this competitive binding assay to measure endogenous binding capacity for cyclosporine (CsA) in erythrocyte lysates, a fixed amount of [ 3 H]CsA plus various concentrations of unlabeled CsA is incubated with aliquots of a test hemolysate. Free CsA is then adsorbed onto charcoal and removed by centrifugation; CsA complexed with a cyclosporine-binding protein (CsBP) remains in the supernate. We confirmed the validity of this charcoal-separation mode of binding analysis by comparison with equilibrium dialysis. Scatchard plot analysis of the results at 4 degrees C yielded a straight line with slope corresponding to a binding constant of 1.9 X 10(7) L/mol and a saturation capacity of approximately 4 mumol per liter of packed erythrocytes. Similar analysis of binding data at 24 degrees C and 37 degrees C showed that the binding constant decreased with increasing temperature, but the saturation capacity did not change. CsBP was not membrane bound but appeared to be freely distributed within erythrocytes. 125 I-labeled CsA did not complex with the erythrocyte CsBP. Several antibiotics and other drugs did not inhibit binding between CsA and CsBP. These findings may explain the temperature-dependent uptake of CsA by erythrocytes in whole blood and suggest that measurement of CsBP in erythrocytes or lymphocytes may help predict therapeutic response or toxicity after administration of CsA

51Cr - erythrocyte survival curves

International Nuclear Information System (INIS)

Paiva Costa, J. de.

1982-07-01

Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt

Plasmodium knowlesi Skeleton-Binding Protein 1 Localizes to the 'Sinton and Mulligan' Stipplings in the Cytoplasm of Monkey and Human Erythrocytes.

Science.gov (United States)

Lucky, Amuza Byaruhanga; Sakaguchi, Miako; Katakai, Yuko; Kawai, Satoru; Yahata, Kazuhide; Templeton, Thomas J; Kaneko, Osamu

2016-01-01

The malaria parasite, Plasmodium, exports protein products to the infected erythrocyte to introduce modifications necessary for the establishment of nutrient acquisition and surface display of host interaction ligands. Erythrocyte remodeling impacts parasite virulence and disease pathology and is well documented for the human malaria parasite Plasmodium falciparum, but has been less described for other Plasmodium species. For P. falciparum, the exported protein skeleton-binding protein 1 (PfSBP1) is involved in the trafficking of erythrocyte surface ligands and localized to membranous structures within the infected erythrocyte, termed Maurer's clefts. In this study, we analyzed SBP1 orthologs across the Plasmodium genus by BLAST analysis and conserved gene synteny, which were also recently described by de Niz et al. (2016). To evaluate the localization of an SBP1 ortholog, we utilized the zoonotic malaria parasite, Plasmodium knowlesi. Immunofluorescence assay of transgenic P. knowlesi parasites expressing epitope-tagged recombinant PkSBP1 revealed a punctate staining pattern reminiscent of Maurer's clefts, following infection of either monkey or human erythrocytes. The recombinant PkSBP1-positive puncta co-localized with Giemsa-stained structures, known as 'Sinton and Mulligan' stipplings. Immunoelectron microscopy also showed that recombinant PkSBP1 localizes within or on the membranous structures akin to the Maurer's clefts. The recombinant PkSBP1 expressed in P. falciparum-infected erythrocytes co-localized with PfSBP1 at the Maurer's clefts, indicating an analogous trafficking pattern. A member of the P. knowlesi 2TM protein family was also expressed and localized to membranous structures in infected monkey erythrocytes. These results suggest that the trafficking machinery and induced erythrocyte cellular structures of P. knowlesi are similar following infection of both monkey and human erythrocytes, and are conserved with P. falciparum.

Magnetic measurements on human erythrocytes: Normal, beta thalassemia major, and sickle

Science.gov (United States)

Sakhnini, Lama

2003-05-01

In this article magnetic measurements were made on human erythrocytes at different hemoglobin states (normal and reduced hemoglobin). Different blood samples: normal, beta thalassemia major, and sickle were studied. Beta thalassemia major and sickle samples were taken from patients receiving lifelong blood transfusion treatment. All samples examined exhibited diamagnetic behavior. Beta thalassemia major and sickle samples showed higher diamagnetic susceptibilities than that for the normal, which was attributed to the increase of membrane to hemoglobin volume ratio of the abnormal cells. Magnetic measurements showed that the erythrocytes in the reduced state showed less diamagnetic response in comparison with erythrocytes in the normal state. Analysis of the paramagnetic component of magnetization curves gave an effective magnetic moment of μeff=7.6 μB per reduced hemoglobin molecule. The same procedure was applied to sickle and beta thalassemia major samples and values for μeff were found to be comparable to that of the normal erythrocytes.

Antioxidant effect of 4-nerolidylcatechol and α-tocopherol in erythrocyte ghost membranes and phospholipid bilayers

International Nuclear Information System (INIS)

Fernandes, K.S.; Silva, A.H.M.; Mendanha, S.A.; Rezende, K.R.; Alonso, A.

2013-01-01

4-Nerolidylcatechol (4-NC) is found in Pothomorphe umbellata root extracts and is reported to have a topical protective effect against UVB radiation-induced skin damage, toxicity in melanoma cell lines, and antimalarial activity. We report a comparative study of the antioxidant activity of 4-NC and α-tocopherol against lipid peroxidation initiated by two free radical-generating systems: 2,2′-azobis(2-aminopropane) hydrochloride (AAPH) and FeSO 4 /H 2 O 2 , in red blood cell ghost membranes and in egg phosphatidylcholine (PC) vesicles. Lipid peroxidation was monitored by membrane fluidity changes assessed by electron paramagnetic resonance spectroscopy of a spin-labeled lipid and by the formation of thiobarbituric acid-reactive substances. When lipoperoxidation was initiated by the hydroxyl radical in erythrocyte ghost membranes, both 4-NC and α-tocopherol acted in a very efficient manner. However, lower activities were observed when lipoperoxidation was initiated by the peroxyl radical; and, in this case, the protective effect of α-tocopherol was lower than that of 4-NC. In egg PC vesicles, malondialdehyde formation indicated that 4-NC was effective against lipoperoxidation initiated by both AAPH and FeSO 4 /H 2 O 2 , whereas α-tocopherol was less efficient in protecting against lipoperoxidation by AAPH, and behaved as a pro-oxidant for FeSO 4 /H 2 O 2 . The DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical assay indicated that two free radicals were scavenged per 4-NC molecule, and one free radical was scavenged per α-tocopherol molecule. These data provide new insights into the antioxidant capacity of 4-NC, which may have therapeutic applications for formulations designed to protect the skin from sunlight irradiation

Investigating the function of F_c -specific binding of IgM to Plasmodium falciparum erythrocyte membrane protein 1 mediating erythrocyte rosetting

DEFF Research Database (Denmark)

Stevenson, Liz; Huda, Pie; Jeppesen, Anine

2015-01-01

of opsonized infected erythrocytes (IEs) without compromising the placental IE adhesion mediated by this PfEMP1 type. IgM also binds via Fc to several other PfEMP1 proteins, where it has been proposed to facilitate rosetting (binding of uninfected erythrocytes to a central IE). To further dissect...

The Membrane Modulates Internal Proton Transfer in Cytochrome c Oxidase

DEFF Research Database (Denmark)

Öjemyr, Linda Nasvik; Ballmoos, Christoph von; Faxén, Kristina

2012-01-01

The functionality of membrane proteins is often modulated by the surrounding membrane. Here, we investigated the effect of membrane reconstitution of purified cytochrome c oxidase (CytcO) on the kinetics and thermodynamics of internal electron and proton-transfer reactions during O-2 reduction...... DOPC lipids. In conclusion, the data show that the membrane significantly modulates internal charge-transfer reactions and thereby the function of the membrane-bound enzyme.......-glycerol) (DOPG). In addition, a small Change in the internal Cu-A-heme a electron equilibrium constant was observed. This effect was lipid-dependent and explained in terms of a lower electrostatic potential within the membrane-spanning part of the protein with the anionic DOPG lipids than with the zwitterionic...

Loading of erythrocyte membrane with pentacyclic triterpenes inhibits Plasmodium falciparum invasion

DEFF Research Database (Denmark)

Ziegler, Hanne L; Staalsø, Trine; Jaroszewski, Jerzy W

2006-01-01

Lupeol and betulinic acid inhibit the proliferation of Plasmodium falciparum parasites by inhibition of the invasion of merozoites into erythrocytes. This conclusion is based on experiments employing parasite cultures synchronized by magnetic cell sorting (MACS). Identical inhibitory effects were...

Binding of two desmin derivatives to the plasma membrane and the nuclear envelope of avian erythrocytes: evidence for a conserved site-specificity in intermediate filament-membrane interactions

International Nuclear Information System (INIS)

Georgatos, S.D.; Weber, K.; Geisler, N.; Blobel, G.

1987-01-01

Using solution binding assays, the authors found that a 45-kDa fragment of 125 I-labelled desmin, lacking 67 residues from the N terminus, could specifically associate with avian erythrocyte nuclear envelopes but not with plasma membranes from the same cells. It was also observed that a 50-kDa desmin peptide, missing 27 C-terminal residues, retained the ability to bind to both membrane preparations. Displacement experiments with an excess of purified vimentin suggested that the two desmin derivatives were interacting with a previously identified vimentin receptor at the nuclear envelope, the protein lamin B. Additional analysis by affinity chromatography confirmed this conclusion. Employing an overlay assay, they demonstrated that the 50-kDa fragment, but not the 45-kDa desmin peptide, was capable of interacting with the plasma membrane polypeptide ankyrin (a known vimentin attachment site), as was intact vimentin. Conversely, the nuclear envelope protein lamin B was recognized by both fragments but not by a chymotryptic peptide composed solely of the helical rod domain of desmin. These data imply that the lamin B-binding site on desmin resides within the 21 residues following its helical rod domain, whereas the ankyrin-associating region is localized within its N-terminal head domain, exactly as in the case of vimentin

Stimulation of Suicidal Erythrocyte Death by Increased Extracellular Phosphate Concentrations

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Jakob Voelkl

2014-02-01

Full Text Available Background/Aim: Anemia in renal insufficiency results in part from impaired erythrocyte formation due to erythropoietin and iron deficiency. Beyond that, renal insufficiency enhances eryptosis, the suicidal erythrocyte death characterized by phosphatidylserine-exposure at the erythrocyte surface. Eryptosis may be stimulated by increase of cytosolic Ca2+-activity ([Ca2+]i. Several uremic toxins have previously been shown to stimulate eryptosis. Renal insufficiency is further paralleled by increase of plasma phosphate concentration. The present study thus explored the effect of phosphate on erythrocyte death. Methods: Cell volume was estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, and [Ca2+]i from Fluo3-fluorescence. Results: Following a 48 hours incubation, the percentage of phosphatidylserine exposing erythrocytes markedly increased as a function of extracellular phosphate concentration (from 0-5 mM. The exposure to 2 mM or 5 mM phosphate was followed by slight but significant hemolysis. [Ca2+]i did not change significantly up to 2 mM phosphate but significantly decreased at 5 mM phosphate. The effect of 2 mM phosphate on phosphatidylserine exposure was significantly augmented by increase of extracellular Ca2+ to 1.7 mM, and significantly blunted by nominal absence of extracellular Ca2+, by additional presence of pyrophosphate as well as by presence of p38 inhibitor SB203580. Conclusion: Increasing phosphate concentration stimulates erythrocyte membrane scrambling, an effect depending on extracellular but not intracellular Ca2+ concentration. It is hypothesized that suicidal erythrocyte death is triggered by complexed CaHPO4.

Plasmodium knowlesi Skeleton-Binding Protein 1 Localizes to the ‘Sinton and Mulligan’ Stipplings in the Cytoplasm of Monkey and Human Erythrocytes

Science.gov (United States)

Lucky, Amuza Byaruhanga; Sakaguchi, Miako; Katakai, Yuko; Kawai, Satoru; Yahata, Kazuhide; Templeton, Thomas J.

2016-01-01

The malaria parasite, Plasmodium, exports protein products to the infected erythrocyte to introduce modifications necessary for the establishment of nutrient acquisition and surface display of host interaction ligands. Erythrocyte remodeling impacts parasite virulence and disease pathology and is well documented for the human malaria parasite Plasmodium falciparum, but has been less described for other Plasmodium species. For P. falciparum, the exported protein skeleton-binding protein 1 (PfSBP1) is involved in the trafficking of erythrocyte surface ligands and localized to membranous structures within the infected erythrocyte, termed Maurer's clefts. In this study, we analyzed SBP1 orthologs across the Plasmodium genus by BLAST analysis and conserved gene synteny, which were also recently described by de Niz et al. (2016). To evaluate the localization of an SBP1 ortholog, we utilized the zoonotic malaria parasite, Plasmodium knowlesi. Immunofluorescence assay of transgenic P. knowlesi parasites expressing epitope-tagged recombinant PkSBP1 revealed a punctate staining pattern reminiscent of Maurer's clefts, following infection of either monkey or human erythrocytes. The recombinant PkSBP1-positive puncta co-localized with Giemsa-stained structures, known as ‘Sinton and Mulligan’ stipplings. Immunoelectron microscopy also showed that recombinant PkSBP1 localizes within or on the membranous structures akin to the Maurer's clefts. The recombinant PkSBP1 expressed in P. falciparum-infected erythrocytes co-localized with PfSBP1 at the Maurer's clefts, indicating an analogous trafficking pattern. A member of the P. knowlesi 2TM protein family was also expressed and localized to membranous structures in infected monkey erythrocytes. These results suggest that the trafficking machinery and induced erythrocyte cellular structures of P. knowlesi are similar following infection of both monkey and human erythrocytes, and are conserved with P. falciparum. PMID:27732628

Global transformation of erythrocyte properties via engagement of an SH2-like sequence in band 3.

Science.gov (United States)

Puchulu-Campanella, Estela; Turrini, Francesco M; Li, Yen-Hsing; Low, Philip S

2016-11-29

Src homology 2 (SH2) domains are composed of weakly conserved sequences of ∼100 aa that bind phosphotyrosines in signaling proteins and thereby mediate intra- and intermolecular protein-protein interactions. In exploring the mechanism whereby tyrosine phosphorylation of the erythrocyte anion transporter, band 3, triggers membrane destabilization, vesiculation, and fragmentation, we discovered a SH2 signature motif positioned between membrane-spanning helices 4 and 5. Evidence that this exposed cytoplasmic sequence contributes to a functional SH2-like domain is provided by observations that: (i) it contains the most conserved sequence of SH2 domains, GSFLVR; (ii) it binds the tyrosine phosphorylated cytoplasmic domain of band 3 (cdb3-PO 4 ) with K d = 14 nM; (iii) binding of cdb3-PO 4 to erythrocyte membranes is inhibited both by antibodies against the SH2 signature sequence and dephosphorylation of cdb3-PO 4 ; (iv) label transfer experiments demonstrate the covalent transfer of photoactivatable biotin from isolated cdb3-PO 4 (but not cdb3) to band 3 in erythrocyte membranes; and (v) phosphorylation-induced binding of cdb3-PO 4 to the membrane-spanning domain of band 3 in intact cells causes global changes in membrane properties, including (i) displacement of a glycolytic enzyme complex from the membrane, (ii) inhibition of anion transport, and (iii) rupture of the band 3-ankyrin bridge connecting the spectrin-based cytoskeleton to the membrane. Because SH2-like motifs are not retrieved by normal homology searches for SH2 domains, but can be found in many tyrosine kinase-regulated transport proteins using modified search programs, we suggest that related cases of membrane transport proteins containing similar motifs are widespread in nature where they participate in regulation of cell properties.

Rapid and specific biotin labelling of the erythrocyte surface antigens of both cultured and ex-vivo Plasmodium parasites

Directory of Open Access Journals (Sweden)

Thompson Joanne

2007-05-01

Full Text Available Abstract Background Sensitive detection of parasite surface antigens expressed on erythrocyte membranes is necessary to further analyse the molecular pathology of malaria. This study describes a modified biotin labelling/osmotic lysis method which rapidly produces membrane extracts enriched for labelled surface antigens and also improves the efficiency of antigen recovery compared with traditional detergent extraction and surface radio-iodination. The method can also be used with ex-vivo parasites. Methods After surface labelling with biotin in the presence of the inhibitor furosemide, detergent extraction and osmotic lysis methods of enriching for the membrane fractions were compared to determine the efficiency of purification and recovery. Biotin-labelled proteins were identified on silver-stained SDS-polyacrylamide gels. Results Detergent extraction and osmotic lysis were compared for their capacity to purify biotin-labelled Plasmodium falciparum and Plasmodium chabaudi erythrocyte surface antigens. The pellet fraction formed after osmotic lysis of P. falciparum-infected erythrocytes is notably enriched in suface antigens, including PfEMP1, when compared to detergent extraction. There is also reduced co-extraction of host proteins such as spectrin and Band 3. Conclusion Biotinylation and osmotic lysis provides an improved method to label and purify parasitised erythrocyte surface antigen extracts from both in vitro and ex vivo Plasmodium parasite preparations.

Induction of Suicidal Erythrocyte Death by Novobiocin

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Adrian Lupescu

2014-03-01

Full Text Available Background: Novobiocin, an aminocoumarin antibiotic, interferes with heat shock protein 90 and hypoxia inducible factor dependent gene expression and thus compromises cell survival. Similar to survival of nucleated cells, erythrocyte survival could be disrupted by eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and by phospholipd scrambling of the cell membrane with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i. The Ca2+ sensitivity of phospholipid scrambling is enhanced by ceramide. The present study explored, whether novobiocin elicits eryptosis. Methods: [Ca2+]i was estimated from Fluo3-fluorescence, ceramide abundance utilizing fluorescent antibodies, cell volume from forward scatter, phosphatidylserine-exposure from annexin V binding. Results: A 48 hours exposure to novobiocin (500 µM was followed by a significant increase of [Ca2+]i, decrease of forward scatter, increase of annexin-V-binding and enhanced ceramide formation. Removal of extracellular Ca2+ virtually abrogated the increase of annexin-V-binding following novobiocin exposure. Conclusions: Novobiocin stimulates eryptosis, an effect at least in part due to entry of extracellular Ca2+ and formation of ceramide.

Modulation of Membrane Protein Lateral Mobility by Polyphosphates and Polyamines

Science.gov (United States)

Schindler, Melvin; Koppel, Dennis E.; Sheetz, Michael P.

1980-03-01

The lateral mobility of fluorescein-labeled membrane glycoproteins was measured in whole unlysed erythrocytes and erythrocyte ghosts by the technique of ``fluorescence redistribution after fusion.'' Measurements were made on polyethylene glycol-fused cell pairs in which only one member of the couplet was initially fluorescently labeled. Diffusion coefficients were estimated from the rate of fluorescence redistribution determined from successive scans with a focused laser beam across individual fused pairs. This technique allows for the analysis of diffusion within cell membranes without the possible damaging photochemical events caused by photobleaching. It was found that lateral mobility of erythrocyte proteins can be increased by the addition of polyphosphates (i.e., ATP and 2,3-diphosphoglycerate) and decreased by the addition of organic polyamines (i.e., neomycin and spermine). This control is exerted by these molecules only when they contact the cytoplasmic side of the membrane and is not dependent upon high-energy phosphates. Microviscosity experiments employing diphenylhexatriene demonstrated no changes in membrane lipid state as a function of these reagents. Our results, in conjunction with data on the physical interactions of cytoskeletal proteins, suggest that the diffusion effector molecules alter the lateral mobility of erythrocyte membrane proteins through modifications of interactions in the shell, which is composed of spectrin, actin, and component 4.1.

Platelet inhibition by nitrite is dependent on erythrocytes and deoxygenation.

Directory of Open Access Journals (Sweden)

Sirada Srihirun

Full Text Available Nitrite is a nitric oxide (NO metabolite in tissues and blood, which can be converted to NO under hypoxia to facilitate tissue perfusion. Although nitrite is known to cause vasodilation following its reduction to NO, the effect of nitrite on platelet activity remains unclear. In this study, the effect of nitrite and nitrite+erythrocytes, with and without deoxygenation, on platelet activity was investigated.Platelet aggregation was studied in platelet-rich plasma (PRP and PRP+erythrocytes by turbidimetric and impedance aggregometry, respectively. In PRP, DEANONOate inhibited platelet aggregation induced by ADP while nitrite had no effect on platelets. In PRP+erythrocytes, the inhibitory effect of DEANONOate on platelets decreased whereas nitrite at physiologic concentration (0.1 µM inhibited platelet aggregation and ATP release. The effect of nitrite+erythrocytes on platelets was abrogated by C-PTIO (a membrane-impermeable NO scavenger, suggesting an NO-mediated action. Furthermore, deoxygenation enhanced the effect of nitrite as observed from a decrease of P-selectin expression and increase of the cGMP levels in platelets. The ADP-induced platelet aggregation in whole blood showed inverse correlations with the nitrite levels in whole blood and erythrocytes.Nitrite alone at physiological levels has no effect on platelets in plasma. Nitrite in the presence of erythrocytes inhibits platelets through its reduction to NO, which is promoted by deoxygenation. Nitrite may have role in modulating platelet activity in the circulation, especially during hypoxia.

Alcohol and the calcium-dependent potassium transport of human erythrocytes

International Nuclear Information System (INIS)

Harris, R.A.; Caldwell, K.K.

1985-01-01

In vitro exposure of human red blood cells to ethanol (100 and 400 mM) was found to increase the initial rate of calcium-dependent potassium efflux through the red cell membrane. This effect of ethanol was apparently not due to an elevation of the intracellular free calcium but rather to a direct action of the drug on the transport process as, (1) intracellular calcium concentrations were tightly buffered with EGTA, (2) ethanol did not alter the efflux of 45 Ca from the cells, and (3) dantrolene, which has been proposed to counteract the effect of ethanol on intracellular calcium levels in the erythrocyte, did not inhibit the stimulatory action of ethanol. The efflux of potassium from erythrocytes obtained from chronic alcoholics was not different from that of erythrocytes from non-alcoholic individuals. The relationship of these findings to neuronal potassium transport is discussed

Antioxidant effect of 4-nerolidylcatechol and α-tocopherol in erythrocyte ghost membranes and phospholipid bilayers

Science.gov (United States)

Fernandes, K.S.; Silva, A.H.M.; Mendanha, S.A.; Rezende, K.R.; Alonso, A.

2013-01-01

4-Nerolidylcatechol (4-NC) is found in Pothomorphe umbellata root extracts and is reported to have a topical protective effect against UVB radiation-induced skin damage, toxicity in melanoma cell lines, and antimalarial activity. We report a comparative study of the antioxidant activity of 4-NC and α-tocopherol against lipid peroxidation initiated by two free radical-generating systems: 2,2′-azobis(2-aminopropane) hydrochloride (AAPH) and FeSO4/H2O2, in red blood cell ghost membranes and in egg phosphatidylcholine (PC) vesicles. Lipid peroxidation was monitored by membrane fluidity changes assessed by electron paramagnetic resonance spectroscopy of a spin-labeled lipid and by the formation of thiobarbituric acid-reactive substances. When lipoperoxidation was initiated by the hydroxyl radical in erythrocyte ghost membranes, both 4-NC and α-tocopherol acted in a very efficient manner. However, lower activities were observed when lipoperoxidation was initiated by the peroxyl radical; and, in this case, the protective effect of α-tocopherol was lower than that of 4-NC. In egg PC vesicles, malondialdehyde formation indicated that 4-NC was effective against lipoperoxidation initiated by both AAPH and FeSO4/H2O2, whereas α-tocopherol was less efficient in protecting against lipoperoxidation by AAPH, and behaved as a pro-oxidant for FeSO4/H2O2. The DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical assay indicated that two free radicals were scavenged per 4-NC molecule, and one free radical was scavenged per α-tocopherol molecule. These data provide new insights into the antioxidant capacity of 4-NC, which may have therapeutic applications for formulations designed to protect the skin from sunlight irradiation. PMID:24068194

Antioxidant effect of 4-nerolidylcatechol and α-tocopherol in erythrocyte ghost membranes and phospholipid bilayers

Energy Technology Data Exchange (ETDEWEB)

Fernandes, K. S.; Silva, A. H.M.; Mendanha, S. A. [Instituto de Física, Universidade Federal de Goiás, Goiânia, GO (Brazil); Rezende, K. R. [Laboratório de Biofarmácia e Farmacocinética de Substâncias Bioativas, Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO (Brazil); Alonso, A. [Instituto de Física, Universidade Federal de Goiás, Goiânia, GO (Brazil)

2013-09-06

4-Nerolidylcatechol (4-NC) is found in Pothomorphe umbellata root extracts and is reported to have a topical protective effect against UVB radiation-induced skin damage, toxicity in melanoma cell lines, and antimalarial activity. We report a comparative study of the antioxidant activity of 4-NC and α-tocopherol against lipid peroxidation initiated by two free radical-generating systems: 2,2′-azobis(2-aminopropane) hydrochloride (AAPH) and FeSO{sub 4}/H{sub 2}O{sub 2}, in red blood cell ghost membranes and in egg phosphatidylcholine (PC) vesicles. Lipid peroxidation was monitored by membrane fluidity changes assessed by electron paramagnetic resonance spectroscopy of a spin-labeled lipid and by the formation of thiobarbituric acid-reactive substances. When lipoperoxidation was initiated by the hydroxyl radical in erythrocyte ghost membranes, both 4-NC and α-tocopherol acted in a very efficient manner. However, lower activities were observed when lipoperoxidation was initiated by the peroxyl radical; and, in this case, the protective effect of α-tocopherol was lower than that of 4-NC. In egg PC vesicles, malondialdehyde formation indicated that 4-NC was effective against lipoperoxidation initiated by both AAPH and FeSO{sub 4}/H{sub 2}O{sub 2}, whereas α-tocopherol was less efficient in protecting against lipoperoxidation by AAPH, and behaved as a pro-oxidant for FeSO{sub 4}/H{sub 2}O{sub 2}. The DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical assay indicated that two free radicals were scavenged per 4-NC molecule, and one free radical was scavenged per α-tocopherol molecule. These data provide new insights into the antioxidant capacity of 4-NC, which may have therapeutic applications for formulations designed to protect the skin from sunlight irradiation.

Stimulation of erythrocyte phosphatidylserine exposure by mercury ions

International Nuclear Information System (INIS)

Eisele, Kerstin; Lang, Philipp A.; Kempe, Daniela S.; Klarl, Barbara A.; Niemoeller, Olivier; Wieder, Thomas; Huber, Stephan M.; Duranton, Christophe; Lang, Florian

2006-01-01

The sequelae of mercury intoxication include induction of apoptosis. In nucleated cells, Hg 2+ -induced apoptosis involves mitochondrial damage. The present study has been performed to elucidate effects of Hg 2+ in erythrocytes which lack mitochondria but are able to undergo apoptosis-like alterations of the cell membrane. Previous studies have documented that activation of a Ca 2+ -sensitive erythrocyte scramblase leads to exposure of phosphatidylserine at the erythrocyte surface, a typical feature of apoptotic cells. The erythrocyte scramblase is activated by osmotic shock, oxidative stress and/or energy depletion which increase cytosolic Ca 2+ activity and/or activate a sphingomyelinase leading to formation of ceramide. Ceramide sensitizes the scramblase to Ca 2+ . The present experiments explored the effect of Hg 2+ ions on erythrocytes. Phosphatidylserine exposure after mercury treatment was estimated from annexin binding as determined in FACS analysis. Exposure to Hg 2+ (1 μM) indeed significantly increased annexin binding from 2.3 ± 0.5% (control condition) to 23 ± 6% (n = 6). This effect was paralleled by activation of a clotrimazole-sensitive K + -selective conductance as measured by patch-clamp recordings and by transient cell shrinkage. Further experiments revealed also an increase of ceramide formation by ∼66% (n = 7) after challenge with mercury (1 μM). In conclusion, mercury ions activate a clotrimazole-sensitive K + -selective conductance leading to transient cell shrinkage. Moreover, Hg 2+ increases ceramide formation. The observed mechanisms could similarly participate in the triggering of apoptosis in nucleated cells by Hg 2+

Direct Cytoskeleton Forces Cause Membrane Softening in Red Blood Cells

Science.gov (United States)

Rodríguez-García, Ruddi; López-Montero, Iván; Mell, Michael; Egea, Gustavo; Gov, Nir S.; Monroy, Francisco

2015-01-01

Erythrocytes are flexible cells specialized in the systemic transport of oxygen in vertebrates. This physiological function is connected to their outstanding ability to deform in passing through narrow capillaries. In recent years, there has been an influx of experimental evidence of enhanced cell-shape fluctuations related to metabolically driven activity of the erythroid membrane skeleton. However, no direct observation of the active cytoskeleton forces has yet been reported to our knowledge. Here, we show experimental evidence of the presence of temporally correlated forces superposed over the thermal fluctuations of the erythrocyte membrane. These forces are ATP-dependent and drive enhanced flickering motions in human erythrocytes. Theoretical analyses provide support for a direct force exerted on the membrane by the cytoskeleton nodes as pulses of well-defined average duration. In addition, such metabolically regulated active forces cause global membrane softening, a mechanical attribute related to the functional erythroid deformability. PMID:26083919

Effect of Aflatoxin B1 - contaminated feed on goat erythrocyte ...

African Journals Online (AJOL)

... action was concentration-dependent, typical of a saturation kinetic effect. The degree of stimulation varied from 20% to more than 90% between the lowest (0.1 M) and highest (1000 M) contentrations. AFB1 induced changes in the apparent kinetic parameters, Km and Vmax, of the erythrocyte membrane-bound enzyme.

IgG antibodies to endothelial protein C receptor-binding Cysteine-rich interdomain region domains of Plasmodium falciparum erythrocyte membrane protein 1 are acquired early in life in individuals exposed to malaria

DEFF Research Database (Denmark)

Turner, Louise; Lavstsen, Thomas; Mmbando, Bruno P

2015-01-01

Severe malaria syndromes are precipitated by Plasmodium falciparum parasites binding to endothelial receptors on the vascular lining. This binding is mediated by members of the highly variant P. falciparum erythrocyte membrane protein 1 (PfEMP1) family. We have previously identified a subset of Pf...

Ultrastructure changes produced by the action of uranyl acetate on the human erythrocyte in vitro

Energy Technology Data Exchange (ETDEWEB)

Wyatt, J H

1975-06-01

Human erythrocytes exposed in vitro to low concentrations of uranyl ions are immediately changed in shape to stomatocytes. Electron microscope examination demonstrates that cellular damage is confined to the plasma membrane. Endocytosis of the cell membrane produces groups of inside out membrane-lined vesicles within the cell; lipid from the membrane enters the cell, giving rise to intracellular myelin figures, and breaks are seen in the cell membrane. It is proposed that the lipid fraction of the cell membrane is the primary target for damage by uranyl ions.

Ultrastructure changes produced by the action of uranyl acetate on the human erythrocyte in vitro

International Nuclear Information System (INIS)

Wyatt, J.H.

1975-06-01

Human erythrocytes exposed in vitro to low concentrations of uranyl ions are immediately changed in shape to stomatocytes. Electron microscope examination demonstrates that cellular damage is confined to the plasma membrane. Endocytosis of the cell membrane produces groups of inside out membrane-lined vesicles within the cell; lipid from the membrane enters the cell, giving rise to intracellular myelin figures, and breaks are seen in the cell membrane. It is proposed that the lipid fraction of the cell membrane is the primary target for damage by uranyl ions. (author)

Comparative studies on osmosis based encapsulation of sodium diclofenac in porcine and outdated human erythrocyte ghosts.

Science.gov (United States)

Bukara, Katarina; Drvenica, Ivana; Ilić, Vesna; Stančić, Ana; Mišić, Danijela; Vasić, Borislav; Gajić, Radoš; Vučetić, Dušan; Kiekens, Filip; Bugarski, Branko

2016-12-20

The objective of our study was to develop controlled drug delivery system based on erythrocyte ghosts for amphiphilic compound sodium diclofenac considering the differences between erythrocytes derived from two readily available materials - porcine slaughterhouse and outdated transfusion human blood. Starting erythrocytes, empty erythrocyte ghosts and diclofenac loaded ghosts were compared in terms of the encapsulation efficiency, drug releasing profiles, size distribution, surface charge, conductivity, surface roughness and morphology. The encapsulation of sodium diclofenac was performed by an osmosis based process - gradual hemolysis. During this process sodium diclofenac exerted mild and delayed antihemolytic effect and increased potassium efflux in porcine but not in outdated human erythrocytes. FTIR spectra revealed lack of any membrane lipid disorder and chemical reaction with sodium diclofenac in encapsulated ghosts. Outdated human erythrocyte ghosts with detected nanoscale damages and reduced ability to shrink had encapsulation efficiency of only 8%. On the other hand, porcine erythrocyte ghosts had encapsulation efficiency of 37% and relatively slow drug release rate. More preserved structure and functional properties of porcine erythrocytes related to their superior encapsulation and release performances, define them as more appropriate for the usage in sodium diclofenac encapsulation process. Copyright © 2016 Elsevier B.V. All rights reserved.

Super-Resolution Microscopy Reveals the Native Ultrastructure of the Erythrocyte Cytoskeleton

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Leiting Pan

2018-01-01

Full Text Available The erythrocyte cytoskeleton is a textbook prototype for the submembrane cytoskeleton of metazoan cells. While early experiments suggest a triangular network of actin-based junctional complexes connected by ∼200-nm-long spectrin tetramers, later studies indicate much smaller junction-to-junction distances in the range of 25-60 nm. Through super-resolution microscopy, we resolve the native ultrastructure of the cytoskeleton of membrane-preserved erythrocytes for the N and C termini of β-spectrin, F-actin, protein 4.1, tropomodulin, and adducin. This allows us to determine an ∼80-nm junction-to-junction distance, a length consistent with relaxed spectrin tetramers and theories based on spectrin abundance. Through two-color data, we further show that the cytoskeleton meshwork often contains nanoscale voids where the cell membrane remains intact and that actin filaments and capping proteins localize to a subset of, but not all, junctional complexes. Together, our results call for a reassessment of the structure and function of the submembrane cytoskeleton.

3D7-derived Plasmodium falciparum erythrocyte membrane protein 1 is a frequent target of naturally acquired antibodies recognizing protein domains in a particular pattern independent of malaria transmission intensity

DEFF Research Database (Denmark)

Joergensen, Louise; Vestergaard, Lasse S; Turner, Louise

2007-01-01

Protection against Plasmodium falciparum malaria is largely mediated by IgG against surface Ags such as the erythrocyte membrane protein 1 family (PfEMP1) responsible for antigenic variation and sequestration of infected erythrocytes. PfEMP1 molecules can be divided into groups A, B/A, B, C, and B......, the sequence by which individuals acquired Abs to particular constructs was largely the same in the three villages. This indicates that the pattern of PfEMP1 expression by parasites transmitted at the different sites was similar, suggesting that PfEMP1 expression is nonrandom and shaped by host......-parasite relationship factors operating at all transmission intensities....

Age related changes in erythrocyte A and B antigen strength

Energy Technology Data Exchange (ETDEWEB)

Hollingsworth, J W; Hamilton, H B; Ishii, Goro

1961-11-01

The strength of A and B antigens of the erythrocyte, as indicated by agglutinability with dilutions of specific antibody, has been investigated in a group of subjects in Hiroshima. Antigen strength was found to rise to maximal levels at age 25 to 29, and decline with advancing years. Degree of irradiation from the Hiroshima atomic bomb in 1945 did not appear in the limited sample to affect this age-dependent structural property of erythrocytes. Antigen strength of females was somewhat less than that of males for those individuals from 20 to 40 years of age. When compared with group A or B subjects, individuals of group AB demonstrated full strength of both A and B antigens. Since Rh antigenicity also has been reported to change with age, it seems probable that multiple changes in the erythrocyte membrane occur with age. Further investigation into the nature of these changes may be fruitful to an understanding of aging processes at the cellular level. 13 references, 1 figure, 6 tables.

Direct measurement of erythrocyte deformability in diabetes mellitus with a transparent microchannel capillary model and high-speed video camera system.

Science.gov (United States)

Tsukada, K; Sekizuka, E; Oshio, C; Minamitani, H

2001-05-01

To measure erythrocyte deformability in vitro, we made transparent microchannels on a crystal substrate as a capillary model. We observed axisymmetrically deformed erythrocytes and defined a deformation index directly from individual flowing erythrocytes. By appropriate choice of channel width and erythrocyte velocity, we could observe erythrocytes deforming to a parachute-like shape similar to that occurring in capillaries. The flowing erythrocytes magnified 200-fold through microscopy were recorded with an image-intensified high-speed video camera system. The sensitivity of deformability measurement was confirmed by comparing the deformation index in healthy controls with erythrocytes whose membranes were hardened by glutaraldehyde. We confirmed that the crystal microchannel system is a valuable tool for erythrocyte deformability measurement. Microangiopathy is a characteristic complication of diabetes mellitus. A decrease in erythrocyte deformability may be part of the cause of this complication. In order to identify the difference in erythrocyte deformability between control and diabetic erythrocytes, we measured erythrocyte deformability using transparent crystal microchannels and a high-speed video camera system. The deformability of diabetic erythrocytes was indeed measurably lower than that of erythrocytes in healthy controls. This result suggests that impaired deformability in diabetic erythrocytes can cause altered viscosity and increase the shear stress on the microvessel wall. Copyright 2001 Academic Press.

Antibodies to variant antigens on the surfaces of infected erythrocytes are associated with protection from malaria in Ghanaian children

DEFF Research Database (Denmark)

Dodoo, D; Staalsoe, T; Giha, H

2001-01-01

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of infected erythrocytes. Each parasite genome contains about 40 PfEMP1 genes, but only 1 PfEMP1 gene is expressed at a given time. PfEMP1 serves as a parasite-sequestering ligand to endoth...

Effect of thiol reactive reagents and ionizing radiation on the permeability of erythrocyte membrane for non-electrolyte spin labels

International Nuclear Information System (INIS)

Gwozdzinski, K.

1986-01-01

The paper presents some results on the effect of PCMB and NEM on the transport of non-electrolyte spin labels: TEMPO and TEMPOL across non-irradiated and irradiated porcine erythrocyte. Irradiated erythrocytes exhibited increased inhibitory effect of thiol reactive compounds in the TEMPO and TEMPOL transport compared to non-irradiated erythrocytes. (orig.)

Atorvastatin acts synergistically with N-acetyl cysteine to provide therapeutic advantage against Fas-activated erythrocyte apoptosis during chronic arsenic exposure in rats

Energy Technology Data Exchange (ETDEWEB)

Biswas, Debabrata; Sen, Gargi; Sarkar, Avik; Biswas, Tuli

2011-01-01

Arsenic is an environmental toxicant that reduces the lifespan of circulating erythrocytes during chronic exposure. Our previous studies had indicated involvement of hypercholesterolemia and reactive oxygen species (ROS) in arsenic-induced apoptotic death of erythrocytes. In this study, we have shown an effective recovery from arsenic-induced death signaling in erythrocytes in response to treatment with atorvastatin (ATV) and N-acetyl cysteine (NAC) in rats. Our results emphasized on the importance of cholesterol in the promotion of ROS-mediated Fas signaling in red cells. Arsenic-induced activation of caspase 3 was associated with phosphatidylserine exposure on the cell surface and microvesiculation of erythrocyte membrane. Administration of NAC in combination with ATV, proved to be more effective than either of the drugs alone towards the rectification of arsenic-mediated disorganization of membrane structural integrity, and this could be linked with decreased ROS accumulation through reduced glutathione (GSH) repletion along with cholesterol depletion. Moreover, activation of caspase 3 was capable of promoting aggregation of band 3 with subsequent binding of autologous IgG and opsonization by C3b that led to phagocytosis of the exposed cells by the macrophages. NAC-ATV treatment successfully amended these events and restored lifespan of erythrocytes from the exposed animals almost to the control level. This work helped us to identify intracellular membrane cholesterol enrichment and GSH depletion as the key regulatory points in arsenic-mediated erythrocyte destruction and suggested a therapeutic strategy against Fas-activated cell death related to enhanced cholesterol and accumulation of ROS.

Lipopeptide-Induced Suicidal Erythrocyte Death Correlates with the Degree of Acylation

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Abdulla Al Mamun Bhuyan

2017-01-01

Full Text Available Background/Aims: Consequences of bacterial infection include anemia, which could result from stimulation of suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Bacterial components known to stimulate eryptosis include lipopeptides. Signaling mediating the triggering of eryptosis include increased cytosolic Ca2+ activity ([Ca2+]i, oxidative stress and cellular accumulation of ceramide. The present study aimed to define the molecular requirements for lipopeptide-induced cell membrane scrambling. Methods: Human erythrocytes were incubated for 48 hours in the absence and presence of 1 or 5 µg/ml of the synthetic lipopeptides Pam1 (lipopeptide with one fatty acid, Pam2 (lipopeptide with two fatty acids, or Pam3 (lipopeptide with three fatty acids. In the following phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCF dependent fuorescence, and ceramide abundance utilizing specific antibodies. Results: Pam1 (5 µg/ml, Pam2 (5 µg/ml and Pam3 (1 and 5 µg/ml significantly increased the percentage of annexin-V-binding to erythrocytes in a dose dependent manner, which was largely independent of Ca2+. Pam1-3 increased the percentage of both, swollen and shrunken erythrocytes without significantly modifying the average forward scatter. They also increased reactive oxygen species (ROS and ceramide abundance. In all assays the effect on eryptosis increased with increasing number of fatty acids, with Pam3 showing always the strongest effect. In contrast, a comparison of the effect of Pam1-3 on TLR2 dependent immune stimulation showed that not Pam3 but Pam2 displayed the strongest activity, and that immune stimulation was triggered at much lower concentrations than eryptosis. Conclusions: Lipopeptides are not only important

Effects of centrifugation on transmembrane water loss from normal and pathologic erythrocytes

International Nuclear Information System (INIS)

Kaperonis, A.A.; Chien, S.

1989-01-01

Plasma 125 I-albumin was used as a marker of extracellular dilution in order to study the effect of high-speed centrifugation on transmembrane water distribution in several types of human red cells, including normal (AA), hemoglobin variants (beta A, AS, SC, beta S, and SS), and those from patients with hereditary spherocytosis. SS and AA erythrocytes were also examined for changes in intracellular hemoglobin concentration of three different density fractions and with increasing duration of spin. The minimum force and duration of centrifugation required to impair water permeability were found to vary with the red cell type, the anticoagulant used (heparin or EDTA), the initial hematocrit of the sample centrifuged, as well as among the individual erythrocyte fractions within the same sample. When subjecting pathologic erythrocytes to high-speed centrifugation, the 125 I-albumin dilution technique can be used to determine whether the centrifugation procedure has led to an artifactual red cell water loss and to correct for this when it does occur. An abnormal membrane susceptibility to mechanical stress was demonstrated in erythrocytes from patients with hereditary spherocytosis and several hemoglobinopathies

UV inactivation of enzymes in supramolecular complexes of biological membranes. The phenomenon of photochemical allotropy

International Nuclear Information System (INIS)

Konev, S.V.; Volotovskij, I.D.; Sheiko, L.M.

1978-01-01

The photosensitivity of erythrocyte acetylcholinesterase (AChE) is different in its free and membrane-bound states. The modification of the structure of membraneous lipids by phospholipases A 2 , C and D or by cholesterol depletion is accompanied by a change in AChE photosensitivity. UV light was demonstrated to induce cooperative structural transitions in the erythrocyte membrane. This follows from the data obtained by circular dichroism and solubilization in detergents. In contrast to free AChE, UV light acts on the membraneous enzyme as a mixed inhibitor (simultaneous change in Vsub(max) and Ksub(m)). The anomalous behaviour of membrane-bound enzyme, termed the phenomenon of photochemical allotropy, is associated with a modification of the structure within the microenvironment of the residual AChE. The phenomenon depends on membrane integrity, and disappears after treatment of erythrocyte ghosts with ultrasound, trypsin, phospholipases and neuraminidase and remains unchanged in cholesterol-depleted membranes. The nature and localization of events responsible for this phenomenon are discussed. (author)

Relation between various phospholipase actions on human red cell membranes and the interfacial phospholipid pressure in monolayers

NARCIS (Netherlands)

Demel, R.A.; Geurts van Kessel, W.S.M.; Zwaal, R.F.A.; Roelofsen, B.; Deenen, L.L.M. van

1975-01-01

The action of purified phospholipases on monomolecular films of various interfacial pressures is compared with the action on erythrocyte membranes. The phospholipases which cannot hydrolyse phospholipids of the intact erythrocyte membrane, phospholipase C from Bacillus cereus, phospholipase A2 from

3. International conference on catalysis in membrane reactors

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-09-01

The 3. International Conference on Catalysis in Membrane Reactors, Copenhagen, Denmark, is a continuation of the previous conferences held in Villeurbanne 1994 and Moscow 1996 and will deal with the rapid developments taking place within membranes with emphasis on membrane catalysis. The approx. 80 contributions in form of plenary lectures and posters discuss hydrogen production, methane reforming into syngas, selectivity and specificity of various membranes etc. The conference is organised by the Danish Catalytic Society under the Danish Society for Chemical Engineering. (EG)

Deformabilidade eritrocitária na anemia ferropriva Erythrocyte deformability in iron deficiency

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Giuseppina M. Patavino

2006-12-01

Full Text Available A deformabilidade é a característica que permite ao eritrócito normal de 7 a 8 micrômetros (µm circular por capilares de até 3 µm de diâmetro. Esse fenômeno depende da geometria celular, da viscosidade interna e de propriedades visco-elásticas da membrana eritrocitária. Dentre as técnicas de estudo da deformabilidade eritrocitária (DE, como aspiração por micropipeta, filtração e reoscopia, destaca-se a ectacitometria. Esta técnica utiliza um viscosímetro de fluxo laminar no qual as modificações de forma dos eritrócitos são monitoradas continuamente por um feixe de raio laser, processadas por microcomputador, gerando o "Índice de Deformabilidade" (ID, que mede a eliptocitogênese dos eritrócitos quando submetidos a uma força denominada "shear stressl". Alterações de DE foram descritas em diversas situações, como em anemias hemolíticas hereditárias ou auto-imunes. Na anemia ferropriva, os trabalhos são controversos. O presente estudo avalia a DE em 21 pacientes portadores de anemia ferropriva, utilizando a ectacitometria. Os resultados obtidos a partir do ID demonstram DE diminuída nesses doentes, quando comparada ao grupo controle (pDeformability allows the 7 to 8 µm red cell to cirDeformability allows the 7- to 8-µm red blood cells to circulate through capillaries of 3 µm. This phenomenon depends on cellular geometry, internal viscosity and viscoelastic properties of the membrane. Among the various techniques of erythrocyte deformability analysis, such as micropipette aspiration, filtration and reoscopy, we chose ektacytometry. This technique uses a laminar flow viscometry, where red blood cell shape changes are continuously monitored by laser, processed by a computer, generating the "Deformability Index", which shows the elliptocytogenesis of the erythrocyte under "shear stressl" force. Erythrocyte deformability has been described in a number of situations like hereditary or autoimmune hemolytic anemia. In

Aquaporin-1-Mediated Effects of Low Level He-Ne Laser Irradiation on Human Erythrocytes

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Gang-Yue Luo

2012-01-01

Full Text Available The role of membrane aquaporin-1 (APQ-1 in the photobiomodulation (PBM on erythrocyte deformability will be studied in this paper with human dehydrated erythrocytes as echinocytic shape alterations lead to decreased cellular deformability. Human dehydrated erythrocytes were irradiated with low intensity He-Ne laser irradiation (LHNL at 0.9, 1.8, 2.7, and 4.4 mW/cm2 for 5, 15, and 30 min, respectively, and APQ-1 inhibitor, 0.2 μmol/L HgCl2, was used to study the role of APQ-1 in mediating PBM with LHNL at 4.4 mW/cm2 for 5 min. Comprehensive morphological parameters of an intact cell such as contact area, perimeter, roundness and erythrocyte elongation index (EEI were measured to characterize erythrocyte deformability with fast micro multi-channel spectrophotometer. It was observed that the dosage of LHNL improvement of the morphological parameters of dehydrated erythrocytes was morphological-parameter-dependent, but the Bunsen-Roscoe rule did not hold for roundness. The LHNL at 4.4 mW/cm2 for 5 min significantly improved the contact area (P<0.05 and EEI (P<0.05 of the dehydrated erythrocytes, but the improvement was significantly inhibited by 0.2 μmol/L HgCl2 (P<0.05. It was concluded that AQP-1 might mediate the effects of LHNL on erythrocyte deformability, which supports the membranotropic mechanism of PBM.

Targeted disruption of a ring-infected erythrocyte surface antigen (RESA)-like export protein gene in Plasmodium falciparum confers stable chondroitin 4-sulfate cytoadherence capacity

DEFF Research Database (Denmark)

Goel, Suchi; Muthusamy, Arivalagan; Miao, Jun

2014-01-01

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family proteins mediate the adherence of infected erythrocytes to microvascular endothelia of various organs, including the placenta, thereby contributing to cerebral, placental, and other severe malaria pathogenesis. Several paras...

[Modification of red cell membranes with perftoran in papaine emphysema in rats].

Science.gov (United States)

Zoirova, N I; Arifkhanov, S I; Rakhmatullaev, Kh U; Tadzhikhodzhaev, Iu Kh

2006-01-01

Papaine emphysema model on 75 mongrel mature white male rats (10 intact rats were control) was used to study the size, form, surface architechtonics, deformability and state of membrane-receptor erythrocyte complex before and after perftoran intraperitoneal administration. Perftoran emulsion produced a membrane-modulating effect with recovery of hormonal reception sensitivity, PHA-, cAMP-receptor systems as well as restoration of erythrocytic normocytosis and diskocytosis.

Detection of erythrocytes influenced by aging and type 2 diabetes using atomic force microscope

Energy Technology Data Exchange (ETDEWEB)

Jin, Hua; Xing, Xiaobo [Chemistry Department, Jinan University, Guangzhou 510632 (China); Zhao, Hongxia [Chemistry Department, Jinan University, Guangzhou 510632 (China); Faculty of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510090 (China); Chen, Yong [Institute for Advanced Study, Nanchang University, Nanchang, Jiangxi 330031 (China); Huang, Xun [Chemistry Department, Jinan University, Guangzhou 510632 (China); Ma, Shuyuan [Chemistry Department, Jinan University, Guangzhou 510632 (China); The First Affiliated Hospital, Jinan University, Guangzhou 510632 (China); Ye, Hongyan [Chemistry Department, Jinan University, Guangzhou 510632 (China); Cai, Jiye, E-mail: tjycai@jnu.edu.cn [Chemistry Department, Jinan University, Guangzhou 510632 (China)

2010-01-22

The pathophysiological changes of erythrocytes are detected at the molecular scale, which is important to reveal the onset of diseases. Type 2 diabetes is an age-related metabolic disorder with high prevalence in elderly (or old) people. Up to now, there are no treatments to cure diabetes. Therefore, early detection and the ability to monitor the progression of type 2 diabetes are very important for developing effective therapies. Type 2 diabetes is associated with high blood glucose in the context of insulin resistance and relative insulin deficiency. These abnormalities may disturb the architecture and functions of erythrocytes at molecular scale. In this study, the aging- and diabetes-induced changes in morphological and biomechanical properties of erythrocytes are clearly characterized at nanometer scale using atomic force microscope (AFM). The structural information and mechanical properties of the cell surface membranes of erythrocytes are very important indicators for determining the healthy, diseased or aging status. So, AFM may potentially be developed into a powerful tool in diagnosing diseases.

Detection of erythrocytes influenced by aging and type 2 diabetes using atomic force microscope

International Nuclear Information System (INIS)

Jin, Hua; Xing, Xiaobo; Zhao, Hongxia; Chen, Yong; Huang, Xun; Ma, Shuyuan; Ye, Hongyan; Cai, Jiye

2010-01-01

The pathophysiological changes of erythrocytes are detected at the molecular scale, which is important to reveal the onset of diseases. Type 2 diabetes is an age-related metabolic disorder with high prevalence in elderly (or old) people. Up to now, there are no treatments to cure diabetes. Therefore, early detection and the ability to monitor the progression of type 2 diabetes are very important for developing effective therapies. Type 2 diabetes is associated with high blood glucose in the context of insulin resistance and relative insulin deficiency. These abnormalities may disturb the architecture and functions of erythrocytes at molecular scale. In this study, the aging- and diabetes-induced changes in morphological and biomechanical properties of erythrocytes are clearly characterized at nanometer scale using atomic force microscope (AFM). The structural information and mechanical properties of the cell surface membranes of erythrocytes are very important indicators for determining the healthy, diseased or aging status. So, AFM may potentially be developed into a powerful tool in diagnosing diseases.

Modulation of erythrocyte membrane mechanical stability by 2,3-diphosphoglycerate in the neonatal poikilocytosis/elliptocytosis syndrome.

Science.gov (United States)

Mentzer, W C; Iarocci, T A; Mohandas, N; Lane, P A; Smith, B; Lazerson, J; Hays, T

1987-01-01

To explain the transient anemia and poikilocytosis seen during infancy in hereditary elliptocytosis (HE), we resealed erythrocyte (RBC) ghosts from affected children or their elliptocytic parents with 2,3-diphosphoglycerate (DPG) (0-8 mM), a compound that dissociates membrane skeletons, then measured ghost mechanical stability in the ektacytometer. Without added 2,3-DPG, ghost mechanical stability was subnormal in infantile poikilocytosis (IP) and HE but was even more abnormal in hereditary pyropoikilocytosis (HPP). Addition of 2,3-DPG (2.55 mM) to IP or HE ghosts, decreased their stability to that of HPP ghosts (without 2,3-DPG). Nonphysiological 2,3-DPG levels (6-8 mM) were required to elicit a similar effect in normal ghosts. The data suggest that free 2,3-DPG, present in neonatal RBC as a consequence of diminished binding to HbF, may render HE susceptible to in vivo fragmentation. The developmental switch from fetal to adult hemoglobin, by diminishing available free 2,3-DPG, may explain the abatement of poikilocytosis and hemolytic anemia that accompanies maturation. Images PMID:3818955

Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

Energy Technology Data Exchange (ETDEWEB)

Krokosz, Anita [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)]. E-mail: krokosz@biol.uni.lodz.pl; Koziczak, Renata [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Gonciarz, Marta [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland); Szweda-Lewandowska, Zofia [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, Lodz (Poland)

2006-01-15

Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with {gamma}-rays at three dose-rates of 66.7, 36.7, 25 Gy min{sup -1} in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect.

Study of the effect of dose-rate on radiation-induced damage to human erythrocytes

International Nuclear Information System (INIS)

Krokosz, Anita; Koziczak, Renata; Gonciarz, Marta; Szweda-Lewandowska, Zofia

2006-01-01

Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%) were irradiated with γ-rays at three dose-rates of 66.7, 36.7, 25 Gy min -1 in order to investigate the influence of the dose-rate on radiation-induced membrane damage, hemoglobin oxidation and loss of reduced glutathione. The obtained results showed that such processes as erythrocyte hemolysis, lipid and protein destruction depend on the radiation dose-rate. The parameter values describing these processes showed an inverse dose-rate effect

Measuring shape fluctuations in biological membranes

International Nuclear Information System (INIS)

Monzel, C; Sengupta, K

2016-01-01

Shape fluctuations of lipid membranes have intrigued cell biologists and physicists alike. In the cellular context, their origin—thermal or active—and their physiological significance are open questions. These small incessant displacements, also called membrane undulations, have mostly been studied in model membranes and membranes of simple cells like erythrocytes. Thermal fluctuations of such membranes have been very well described both theoretically and experimentally; active fluctuations are a topic of current interest. Experimentally, membrane fluctuations are not easy to measure, the main challenge being to develop techniques which are capable of measuring very small displacements at very high speed, and preferably over a large area and long time. Scattering techniques have given access to fluctuations in membrane stacks and a variety of optical microscopy based techniques have been devised to study membrane fluctuations of unilamellar vesicles, erythrocytes and other cells. Among them are flicker spectroscopy, dynamic light scattering, diffraction phase microscopy and reflection interference contrast microscopy. Each of these techniques has its advantages and limitations. Here we review the basic principles of the major experimental techniques used to measure bending or shape fluctuations of biomembranes. We report seminal results obtained with each technique and highlight how these studies furthered our understanding of physical properties of membranes and their interactions. We also discuss suggested role of membrane fluctuations in different biological processes. (topical review)

Morphological characteristics of urine erythrocytes in children with erythrocyturia

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V.A. Minakova

2017-09-01

Full Text Available Background. Nephropathies with erythrocyturia make up about 1/3 of all diseases of the kidneys and the urinary system, and they have some difficulties in differential diagnostics. Quite often, erythrocyturia is the only symptom of these diseases. In connection with this, determination of its origin is an important task in forming the correct diagnosis. Erythrocyturia in most diseases of the lower urinary tract is not accompanied by proteinuria or the presence of cylinders in the urine. The presence of proteinuria (more than 0.3 g/l or 1 g protein in urine per day, along with the appearance of erythrocytic cylinder in the urine sediment, raises suspicion in favor of glomerular or tubular diseases. Glomerular erythrocytes may be detected by means of urea concentration factor (UCF in the urinary sediment as a preliminary test for the determination of the erythrocyturia site. Erythrocytes that pass through the glomerular membrane have a changed form (dysmorphic. Determination of acanthocytes in the urine (ring-shaped erythrocytes with one or several bulges in the form of bubbles of different sizes and types is a more precise criterion of glomerular nephropathy than the presence of dysmorphic erythrocytes. The purpose of the study was to determine the morphological characteristics of urine erythrocytes in children with erythrocyturia, to improve the quality of differential diagnosis. Materials and methods. Determination of the morphological characteristics of urinary erythrocytes using UCF in 73 patients aged 1 to 18 years, of which 45 (61.6 % are patients with hematuric form of glomerulonephritis, 23 (31.5 % — with hereditary nephritis, and 5 (6.8 % — with dysmetabolic nephropathy. Detection of 50 to 80 % of dysmorphic erythrocytes in the urine sediment and finding in urine of more than 5 % of acanthocytes is a highly sensitive and specific diagnostic criterion for glomerular hematuria. Results. In children with a clinical diagnosis �

Modification of host erythrocyte membranes by trypsin and chymotrypsin treatments and effects on the in vitro growth of bovine and equine Babesia parasites.

Science.gov (United States)

Okamura, Masashi; Yokoyama, Naoaki; Takabatake, Noriyuki; Okubo, Kazuhiro; Ikehara, Yuzuru; Igarashi, Ikuo

2007-02-01

In the present study, we investigated the effects of protease pretreatments of host erythrocytes (RBC) on the in vitro growth of bovine Babesia parasites (Babesia bovis and B. bigemina) and equine Babesia parasites (B. equi and B. caballi). The selected proteases, trypsin and chymotrypsin, clearly modified several membrane proteins of both bovine and equine RBC, as demonstrated by SDS-PAGE analysis; however, the protease treatments also modified the sialic acid content exclusively in bovine RBC, as demonstrated by lectin blot analysis. An in vitro growth assay using the protease-treated RBC showed that the trypsin-treated bovine RBC, but not the chymotrypsin-treated ones, significantly reduced the growth of B. bovis and B. bigemina as compared to the control. In contrast, the growth of B. equi and B. caballi was not affected by any of these proteases. Thus, the bovine, but not the equine, Babesia parasites require the trypsin-sensitive membrane (sialoglyco) proteins to infect the RBC.

Polymorphism in the Mr 32,000 Rh protein purified from Rh(D)-positive and -negative erythrocytes

International Nuclear Information System (INIS)

Saboori, A.M.; Smith, B.L.; Agre, P.

1988-01-01

A M r 32,000 integral membrane protein has previously been identified on erythrocytes bearing the Rh(D) antigen and is thought to contain the antigenic variations responsible for the different Rh phenotypes. To study it on a biochemical level, a simple large-scale method was developed to purify the M r 32,000 Rh protein from multiple units of Rh(D)-positive and -negative blood. Erythrocyte membrane vesicles were solubilized in NaDodSO 4 , and a tracer of immunoprecipitated 125 I surface-labeled Rh protein was added. The Rh protein was purified to homogeneity by hydroxylapatite chromatography followed by preparative NaDodSO 4 /PAGE. Approximately 25 nmol of pure Rh protein was recovered from each unit of Rh(D)-positive and -negative blood. Rh protein purified from both Rh phenotypes appeared similar by one-dimensional NaDodSO 4 /PAGE, and the N-terminal amino acid sequences for the first 20 residues were identical. Rh proteins purified from Rh(D)-positive and -negative blood were compared by two-dimensional iodopeptide mapping after 125 I-labeling and α-chymotrypsin digestion. The peptide maps were very similar. These data indicate that a similar core Rh protein exists in both Rh(D)-positive and -negative erythrocytes, and the Rh proteins from erythrocytes with different Rh phenotypes contain distinct structural polymorphisms

Effects of centrifugation on transmembrane water loss from normal and pathologic erythrocytes

Energy Technology Data Exchange (ETDEWEB)

Kaperonis, A.A.; Chien, S.

1989-02-01

Plasma /sup 125/I-albumin was used as a marker of extracellular dilution in order to study the effect of high-speed centrifugation on transmembrane water distribution in several types of human red cells, including normal (AA), hemoglobin variants (beta A, AS, SC, beta S, and SS), and those from patients with hereditary spherocytosis. SS and AA erythrocytes were also examined for changes in intracellular hemoglobin concentration of three different density fractions and with increasing duration of spin. The minimum force and duration of centrifugation required to impair water permeability were found to vary with the red cell type, the anticoagulant used (heparin or EDTA), the initial hematocrit of the sample centrifuged, as well as among the individual erythrocyte fractions within the same sample. When subjecting pathologic erythrocytes to high-speed centrifugation, the /sup 125/I-albumin dilution technique can be used to determine whether the centrifugation procedure has led to an artifactual red cell water loss and to correct for this when it does occur. An abnormal membrane susceptibility to mechanical stress was demonstrated in erythrocytes from patients with hereditary spherocytosis and several hemoglobinopathies.

Quantitative evaluation of respiration induced metabolic oscillations in erythrocytes

DEFF Research Database (Denmark)

Hald, Bjørn; Madsen, Mads F; Danø, Sune

2009-01-01

The changes in the partial pressures of oxygen and carbon dioxide (P(O(2)) and P(CO(2))) during blood circulation alter erythrocyte metabolism, hereby causing flux changes between oxygenated and deoxygenated blood. In the study we have modeled this effect by extending the comprehensive kinetic...... model by Mulquiney and Kuchel [P.J. Mulquiney, and P.W. Kuchel. Model of 2,3-bisphosphoglycerate metabolism in the human erythrocyte based on detailed enzyme kinetic equations: equations and parameter refinement, Biochem. J. 1999, 342, 581-596.] with a kinetic model of hemoglobin oxy...... solely by steady state consideration. The metabolic system exhibits a broad distribution of time scales. Relaxations of modes with hemoglobin and Mg(2+) binding reactions are very fast, while modes involving glycolytic, membrane transport and 2,3-BPG shunt reactions are much slower. Incomplete slow mode...

Loss of the clock protein PER2 shortens the erythrocyte life span in mice.

Science.gov (United States)

Sun, Qi; Zhao, Yue; Yang, Yunxia; Yang, Xiao; Li, Minghui; Xu, Xi; Wen, Dan; Wang, Junsong; Zhang, Jianfa

2017-07-28

Cell proliferation and release from the bone marrow have been demonstrated to be controlled by circadian rhythms in both humans and mice. However, it is unclear whether local circadian clocks in the bone marrow influence physiological functions and life span of erythrocytes. Here, we report that loss of the clock gene Per2 significantly decreased erythrocyte life span. Mice deficient in Per2 were more susceptible to acute stresses in the erythrocytes, becoming severely anemic upon phenylhydrazine, osmotic, and H 2 O 2 challenges. 1 H NMR-based metabolomics analysis revealed that the Per2 depletion causes significant changes in metabolic profiles of erythrocytes, including increased lactate and decreased ATP levels compared with wild-type mice. The lower ATP levels were associated with hyperfunction of Na + /K + -ATPase activity in Per2 -null erythrocytes, and inhibition of Na + /K + -ATPase activity by ouabain efficiently rescued ATP levels. Per2 -null mice displayed increased levels of Na + /K + -ATPase α1 (ATP1A1) in the erythrocyte membrane, and transfection of Per2 cDNA into the erythroleukemic cell line TF-1 inhibited Atp1a1 expression. Furthermore, we observed that PER2 regulates Atp1a1 transcription through interacting with trans-acting transcription factor 1 (SP1). Our findings reveal that Per2 function in the bone marrow is required for the regulation of life span in circulating erythrocytes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Effect of Lidocaine and Epinephrine on Human Erythrocyte Shape and Vesiculability of Blood Cells

Directory of Open Access Journals (Sweden)

Tanja Slokar

2015-01-01

Full Text Available The effect of local anesthetic composed of lidocaine and epinephrine on vesiculability of blood cells and erythrocyte shape was studied. Whole blood and plasma were incubated with lidocaine/epinephrine. Extracellular vesicles were isolated by centrifugation and washing and counted by flow cytometry. Lidocaine/epinephrine and each component alone were added to diluted blood. Shape changes were recorded by micrographs. An ensemble of captured frames was analyzed for populations of discocytes, echinocytes, and stomatocytes by using statistical methods. Incubation of whole blood and blood plasma with lidocaine/epinephrine considerably increased concentration of extracellular vesicles in isolates (for an average factor 3.4 in blood and 2.8 in plasma. Lidocaine/epinephrine caused change of erythrocyte shape from mainly discocytic to mainly stomatocytic (higher than 50%. Lidocaine alone had even stronger stomatocytic effect (the percent of stomatocytes was higher than 95% while epinephrine had echinocytic effect (the percent of echinocytes was higher than 80%. The differences were highly statistically significant p<10-8 with statistical power P=1. Lidocaine/epinephrine induced regions of highly anisotropically curved regions indicating that lidocaine and epinephrine interact with erythrocyte membrane. It was concluded that lidocaine/epinephrine interacts with cell membranes and increases vesiculability of blood cells in vitro.

Effect of green laser light on diabetes mellitus changed ATPase activity in erythrocytes

International Nuclear Information System (INIS)

Kassak, P.; Sikurova, L.

2006-01-01

Changes in the membrane bound enzyme activity may report about changes of processes and properties related to the cytoplasmic membrane of cells. Activity of the Na + /K + -ATPase has become objective of our investigation as o tool to evaluate changes of diabetic membranes in comparison to normal membranes of human erythrocytes after laser irradiation with Nd:YAG laser (532 nm) in fluence range 9.5-63.3 J · cm -2 . Energies of irradiation 3-20 joules and output power of the laser 30 mW classify this experiment as low-level laser therapy. Bio-stimulation of the enzyme, its activity as well as type-2 diabetes caused disorganisation and alternation of biological membrane and enzyme properties are discussed. (Authors)

The Aotus nancymaae erythrocyte proteome and its importance for biomedical research.

Science.gov (United States)

Moreno-Pérez, D A; García-Valiente, R; Ibarrola, N; Muro, A; Patarroyo, M A

2017-01-30

The Aotus nancymaae species has been of great importance in researching the biology and pathogenesis of malaria, particularly for studying Plasmodium molecules for including them in effective vaccines against such microorganism. In spite of the forgoing, there has been no report to date describing the biology of parasite target cells in primates or their biomedical importance. This study was thus designed to analyse A. nancymaae erythrocyte protein composition using MS data collected during a previous study aimed at characterising the Plasmodium vivax proteome and published in the pertinent literature. Most peptides identified were similar to those belonging to 1189 Homo sapiens molecules; >95% of them had orthologues in New World primates. GO terms revealed a correlation between categories having the greatest amount of proteins and vital cell function. Integral membrane molecules were also identified which could be possible receptors facilitating interaction with Plasmodium species. The A. nancymaae erythrocyte proteome is described here for the first time, as a starting point for more in-depth/extensive studies. The data reported represents a source of invaluable information for laboratories interested in carrying out basic and applied biomedical investigation studies which involve using this primate. An understanding of the proteomics characteristics of A. nancymaae erythrocytes represents a fascinating area for research regarding the study of the pathogenesis of malaria since these are the main target for Plasmodium invasion. However, and even though Aotus is one of the non-human primate models considered most appropriate for biomedical research, knowledge of its proteome, particularly its erythrocytes, remains unknown. According to the above and bearing in mind the lack of information about the A. nancymaae species genome and transcriptome, this study involved a search for primate proteins for comparing their MS/MS spectra with the available information for

Effects of internal limiting membrane peeling during vitrectomy for macula-off primary rhegmatogenous retinal detachment.

Science.gov (United States)

Blanco-Teijeiro, María José; Bande Rodriguez, Manuel; Mansilla Cuñarro, Raquel; Paniagua Fernández, Laura; Ruiz-Oliva Ruiz, Francisco; Piñeiro Ces, Antonio

2018-03-01

To determine the effectiveness of internal limiting membrane peeling during vitrectomy for macula-off primary rhegmatogenous retinal detachment in the prevention of postoperative epiretinal membrane formation and achievement of good visual outcomes and to identify preoperative and intraoperative risk factors for epiretinal membrane formation. We retrospectively analyzed data from 62 eyes of 62 consecutive patients with macula-off primary rhegmatogenous retinal detachment who underwent vitrectomy with (n = 30) or without (n = 32) internal limiting membrane peeling between January 2014 and March 2016 and were followed up for at least 12 months. The effects of internal limiting membrane peeling on visual outcomes and postoperative recovery of the macular structure were determined. We subsequently divided patients into an epiretinal membrane group and a non-epiretinal membrane group and assessed the effects of various preoperative and intraoperative factors on postoperative epiretinal membrane formation. Postoperative epiretinal membrane developed in 10 patients in the no internal limiting membrane peeling group and three patients in the internal limiting membrane peeling group. Postoperative visual acuity significantly improved in both groups. Epiretinal membrane formation was found to be correlated with a higher number of retinal breaks. Our results suggest that internal limiting membrane peeling during macula-off primary rhegmatogenous retinal detachment surgery can reduce the occurrence of postoperative epiretinal membrane, is safe, and results in favorable visual outcomes.

Cytoplasmic free Ca2+ is essential for multiple steps in malaria parasite egress from infected erythrocytes

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Glushakova Svetlana

2013-01-01

Full Text Available Abstract Background Egress of Plasmodium falciparum, from erythrocytes at the end of its asexual cycle and subsequent parasite invasion into new host cells, is responsible for parasite dissemination in the human body. The egress pathway is emerging as a coordinated multistep programme that extends in time for tens of minutes, ending with rapid parasite extrusion from erythrocytes. While the Ca2+ regulation of the invasion of P. falciparum in erythrocytes is well established, the role of Ca2+ in parasite egress is poorly understood. This study analysed the involvement of cytoplasmic free Ca2+ in infected erythrocytes during the multistep egress programme of malaria parasites. Methods Live-cell fluorescence microscopy was used to image parasite egress from infected erythrocytes, assessing the effect of drugs modulating Ca2+ homeostasis on the egress programme. Results A steady increase in cytoplasmic free Ca2+ is found to precede parasite egress. This increase is independent of extracellular Ca2+ for at least the last two hours of the cycle, but is dependent upon Ca2+ release from internal stores. Intracellular BAPTA chelation of Ca2+ within the last 45 minutes of the cycle inhibits egress prior to parasitophorous vacuole swelling and erythrocyte membrane poration, two characteristic morphological transformations preceding parasite egress. Inhibitors of the parasite endoplasmic reticulum (ER Ca2+-ATPase accelerate parasite egress, indicating that Ca2+ stores within the ER are sufficient in supporting egress. Markedly accelerated egress of apparently viable parasites was achieved in mature schizonts using Ca2+ ionophore A23187. Ionophore treatment overcomes the BAPTA-induced block of parasite egress, confirming that free Ca2+ is essential in egress initiation. Ionophore treatment of immature schizonts had an adverse effect inducing parasitophorous vacuole swelling and killing the parasites within the host cell. Conclusions The parasite egress

Ion exchange mechanisms on the erythrocyte membrane of the aquatic salamander, Amphiuma tridactylum

DEFF Research Database (Denmark)

Tufts, B L; Nikinmaa, M; Steffensen, J F

1987-01-01

The effects of different pharmacological agents and incubation media on the intracellular pH and water content of Amphiuma erythrocytes were investigated in vitro. Adrenaline had no significant effect on the intracellular pH or cell water content. DIDS caused an intracellular alkalinization that ...

THE IMPORTANCE OF THE ERYTHROCYTES OSMOTIC FRAGILITY TEST PERFORMED IN CHILDREN WITH INDIRECT HYPERBILIRUB1NEMIA

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Ivana Stojanović

2005-07-01

Full Text Available The osmotic fragility test of erythrocytes is useful in the diagnosis of different types of hereditary hemolytic anemias followed with hyperbilirubinemia. Hemolytic anemias, characterized by accelerated destruction of red blood cells, are usually the consequence of many metabolic abnormalities like cellular membrane defect, erythrocyte enzymes defect or hemoglobin abnormalities – hemoglobinopathies. The object of our study was to assess the relationship between osmotic fragility test of erythrocytes and severity of indirect hyperbilirubinemia in some inherited erythrocytes’ disorders. We did the osmotic fragility test of erythrocytes by using Dacie, s method with normal values of erythrocytes hemolysis between 0,48 to 0,34% NaCl (minimal to maximal hemolysis. In hereditary spherocytosis, fragility of erythrocytes was increased (min. at 0,50 % NaCl to max. 0,44 % NaCl . In the child with β- thalassemia and cycle cell anemia erythrocytes fragility was decreased (min . at 0,42 to max. 0,32 % NaCl, that is 0,40% min. of hemolysis and 0,34% max. hemolysis in the second case. In newborn infants with high levels of indirect bilirubin in serum as a cause of physiological jaundice, the osmotic fragility test was within a normal range. Our findings point out the diagnostic value of osmotic fragility test in assessing patients with the indirect hyperbilirubinemia. This simple and important diagnostic test can be performed in small laboratories.

Antioxidant status of erythrocytes and their response to oxidative challenge in humans with argemone oil poisoning

International Nuclear Information System (INIS)

Babu, Challagundla K.; Khanna, Subhash K.; Das, Mukul

2008-01-01

Oxidative damage of biomolecules and antioxidant status in erythrocytes of humans from an outbreak of argemone oil (AO) poisoning in Kannauj (India) and AO intoxicated experimental animals was investigated. Erythrocytes of the dropsy patients and AO treated rats were found to be more susceptible to 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH) induced peroxidative stress. Significant decrease in RBC glutathione (GSH) levels (46, 63%) with concomitant enhancement in oxidized glutathione (172, 154%) levels was noticed in patients and AO intoxicated animals. Further, depletion of glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G-6-PDH) and glutathione-S-transferase (GST) (42-52%) was observed in dropsy patients. Oxidation of erythrocyte membrane lipids and proteins was increased (120-144%) in patients and AO treated animals (112-137%) along with 8-OHdG levels in whole blood (180%) of dropsy patients. A significant reduction in α-tocopherol content (68%) was noticed in erythrocytes of dropsy patients and hepatic, plasma and RBCs of AO treated rats (59-70%) thereby indicating the diminished antioxidant potential to scavenge free radicals or the limited transport of α-tocopherol from liver to RBCs leading to enhanced oxidation of lipids and proteins in erythrocytes. These studies implicate an important role of erythrocyte degradation in production of anemia and breathlessness in epidemic dropsy

Effect of radiation on sodium and water transport in rat erythrocytes and possible repair using olive oil

International Nuclear Information System (INIS)

Othman, A.I.; El-Missiry, M.A.

1991-01-01

Gamma radiation dose 4 Gy was administered to whole rats, and sodium, water transport and sulfhydryl groups (-SH) contents of the erythrocytes were evaluated in vivo at postirradiation times 1, 3 and 7 days. The present results showed increased sodium and water gain associated with loss of sulfhydryl contents of the erythrocytes. These results are attributed to inhibition of Na pump activity and increased Na leakage into cells which increased the intracellular osmotic elements that lead to influx of water. These changes were secondary to the destruction of erythrocyte -SH groups which was investigated as a change in tertiary structure of the membrane proteins. Olive oil administered intraperitoneally resulted in restoration of the status of the studied parameters. We also noticed an increase in the amount of plasma unsaturated fatty acids including phospholipids. The relation between the reappearance of erythrocyte -SH groups and increased plasma phospholipids suggested a repair role for olive oil. This is through reconstitution of the Na-pump activity in erythrocytes by reactivation of (Na-K) ATPase stimulated by negatively charged plasma phospholipids.4 fig.,1 tab. i

Influence of magnesium sulfate on HCO3/Cl transmembrane exchange rate in human erythrocytes.

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Chernyshova, Ekaterina S; Zaikina, Yulia S; Tsvetovskaya, Galina A; Strokotov, Dmitry I; Yurkin, Maxim A; Serebrennikova, Elena S; Volkov, Leonid; Maltsev, Valeri P; Chernyshev, Andrei V

2016-03-21

Magnesium sulfate (MgSO4) is widely used in medicine but molecular mechanisms of its protection through influence on erythrocytes are not fully understood and are considerably controversial. Using scanning flow cytometry, in this work for the first time we observed experimentally (both in situ and in vitro) a significant increase of HCO3(-)/Cl(-) transmembrane exchange rate of human erythrocytes in the presence of MgSO4 in blood. For a quantitative analysis of the obtained experimental data, we introduced and verified a molecular kinetic model, which describes activation of major anion exchanger Band 3 (or AE1) by its complexation with free intracellular Mg(2+) (taking into account Mg(2+) membrane transport and intracellular buffering). Fitting the model to our in vitro experimental data, we observed a good correspondence between theoretical and experimental kinetic curves that allowed us to evaluate the model parameters and to estimate for the first time the association constant of Mg(2+) with Band 3 as KB~0.07mM, which is in agreement with known values of the apparent Mg(2+) dissociation constant (from 0.01 to 0.1mM) that reflects experiments on enrichment of Mg(2+) at the inner erythrocyte membrane (Gunther, 2007). Results of this work partly clarify the molecular mechanisms of MgSO4 action in human erythrocytes. The method developed allows one to estimate quantitatively a perspective of MgSO4 treatment for a patient. It should be particularly helpful in prenatal medicine for early detection of pathologies associated with the risk of fetal hypoxia. Copyright © 2016 Elsevier Ltd. All rights reserved.

Experimental study on the deformation of erythrocytes under optically trapping and stretching

International Nuclear Information System (INIS)

Liu, Y.P.; Li Chuan; Lai, A.C.K.

2006-01-01

The mechanical behavior of erythrocytes is studied experimentally and numerically. In the experiment, prepared silica microbeads are attached to the surface of spherically swollen erythrocytes (red blood cells, RBCs) at room temperature (25 deg. C). The cells are then stretched by single laser beam via the microbeads. The relation of deformation and stretching force is quantitatively assessed by the image processing of digital pictures. Meanwhile, a physical model for an axisymmetric cell is introduced to study its deformation by different level of stretching force. By comparing the experimental and numerical data, stiffness of the cell membrane can be determined and the optimal values are found to agree with other studies by different techniques such as micropipette aspiration or high frequency electric field

Protective Effect of Theaflavin on Erythrocytes Subjected to In Vitro Oxidative Stress

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Mahejabeen Fatima

2013-01-01

Full Text Available Antioxidant and free radical scavenging effect of black tea theaflavins has been shown in many epidemiological studies. In the present work we report the protective mechanism of tea theaflavins on biomarkers of oxidative stress, which are elevated during stress conditions. We hereby report the in vitro effect of theaflavins on erythrocyte malondialdehyde (MDA, intracellular reduced glutathione (GSH, and plasma membrane redox system (PMRS of rats. The effect of theaflavin on PMRS has also been validated through an in silico docking simulation study using Molegro Virtual Docker (MVD. We report that theaflavins show significant protection to erythrocyte against oxidative stress induced by tert-butyl hydroperoxide (t-BHP. The findings suggest a possible protective role of theaflavins as antioxidant.

Surface co-expression of two different PfEMP1 antigens on single Plasmodium falciparum-infected erythrocytes facilitates binding to ICAM1 and PECAM1

DEFF Research Database (Denmark)

Joergensen, Louise; Bengtsson, Dominique C; Bengtsson, Anja

2010-01-01

The Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) antigens play a major role in cytoadhesion of infected erythrocytes (IE), antigenic variation, and immunity to malaria. The current consensus on control of variant surface antigen expression is that only one PfEMP1 encoded by one var...

Membrane Stabilizing Activity And Phytochemistry Of Hibiscus rosa ...

African Journals Online (AJOL)

The human erythrocyte membrane stabilizing activity of saline extract of Hibiscus rosa-sinensis leaves was investigated as part of efforts at validating its use as anti-arthritic and anti-inflammatory agent. The results of the membrane stabilizing activity of the extract, when compared to two non-steroidal anti-inflammatory drugs ...

Molecular cloning of human protein 4.2: A major component of the erythrocyte membrane

International Nuclear Information System (INIS)

Sung, L.A.; Chien, Shu; Lambert, K.; Chang, Longsheng; Bliss, S.A.; Bouhassira, E.E.; Nagel, R.L.; Schwartz, R.S.; Rybicki, A.C.

1990-01-01

Protein 4.2 (P4.2) comprises ∼5% of the protein mass of human erythrocyte (RBC) membranes. Anemia occurs in patients with RBCs deficient in P4.2, suggesting a role for this protein in maintaining RBC stability and integrity. The authors now report the molecular cloning and characterization of human RBC P4.2 cDNAs. By immunoscreening a human reticulocyte cDNA library and by using the polymerase chain reaction, two cDNA sequences of 2.4 and 2.5 kilobases (kb) were obtained. These cDNAs differ only by a 90-base-air insert in the longer isoform located three codons downstream from the putative initiation site. The 2.4- and 2.5-kb cDNAs predict proteins of ∼77 and ∼80 kDa, respectively, and the authenticity was confirmed by sequence identity with 46 amino acids of three cyanogen bromide-cleaved peptides of P4.2. Northern blot analysis detected a major 2.4-kb RNA species in reticulocytes. Isolation of two P4.2 cDNAs implies existence of specific regulation of P4.2 expression in human RBCs. Human RBC P4.2 has significant homology with human factor XIII subunit a and guinea pig liver transglutaminase. Sequence alignment of P4.2 with these two transglutaminases, however, revealed that P4.2 lacks the critical cysteine residue required for the enzymatic crosslinking of substrates

The effect of membrane diffusion potential change on anionic drugs ...

African Journals Online (AJOL)

The effect of membrane potential change on anionic drugs Indomethacin and barbitone induced human erythrocyte shape change and red cell uptake of drug has been studied using microscopy and spectrophotometry techniques respectively. The membrane potential was changed by reducing the extracellular chloride ...

DETRIMENTAL EFFECTS OF ACTIVE INTERNAL LIMITING MEMBRANE PEELING DURING EPIRETINAL MEMBRANE SURGERY: Microperimetric Analysis.

Science.gov (United States)

Deltour, Jean-Baptiste; Grimbert, Pierre; Masse, Helene; Lebreton, Olivier; Weber, Michel

2017-03-01

The aim of the study was to assess the microperimetric consequences of active internal limiting membrane (ILM) peeling during idiopathic epimacular membrane (IEMM) surgery. This retrospective monocentric study included 32 eyes of 31 consecutive patients who underwent IEMM surgery. Internal limiting membrane integrity was assessed by ILM Blue staining after IEMM removal: peeling was spontaneous (Group S) or active (Group A). Preprocedure and postprocedure (1 and 6 months) examinations were performed using visual acuity determination, spectral domain optical coherence tomography and microperimetry. Twenty-two eyes had an "active ILM peeling" and 10 a "spontaneous ILM peeling." Both groups had comparable and significant improvements in visual acuity 6 months after surgery (+1.82 lines [+9 letters] [Group A] and +1.51 lines [+8 letters] [Group S], P peeling has progressively become generalized in IEMM surgery to reduce recurrences. This additional procedure does not change the postoperative visual acuity but increases the development of deeper microscotomas. The real impact on the quality of vision remains unclear. Active ILM peeling in IEMM surgery may be responsible for visual impairment related to its microtraumatic effects.

Relationship between serum leptin levels, ATPase activity of erythrocyte membrance and development of diabetic nephropathy in patients with DM2

International Nuclear Information System (INIS)

Wang Yuming

2009-01-01

Objective: To study the possible mechanism of development of nephrosis affected by changes of serum leptin levels and alteration of activities of Na + K + -ATPase and Ca 2+ Mg 2+ -ATPase of erythrocyte membrane in patients with type 2 diabetes(DM2). Methods: Serum leptin levels (with RIA) and erythrocyte membrane Na + K + -ATPase and Ca 2+ Mg 2+ -ATPase activitities (with Reinila method) were determined in 40 DM2 patients without nephropathy, 32 DM2 patients with nephropathy and 35 controls. Results Serum leptin levels were significantly higher in the diabetics as a whole than those in controls (P + K + -ATPase and Ca 2+ Mg 2+ -ATPase activities were significantly lower (P<0.01). Among the diabetic patients, the serum leptin levels in patients without nephrosis (P<0.05), but the RBC membrance ATPase activities were significantly lower(P<0.05). Conclusion: Development of type 2 diabetes nephrosis might be correlated with the high serum leptin level and decreased ATPase activities of erythrocite membrane. (authors)

Membrane properties involved in calcium-stimulated microparticle release from the plasma membranes of S49 lymphoma cells.

Science.gov (United States)

Campbell, Lauryl E; Nelson, Jennifer; Gibbons, Elizabeth; Judd, Allan M; Bell, John D

2014-01-01

This study answered the question of whether biophysical mechanisms for microparticle shedding discovered in platelets and erythrocytes also apply to nucleated cells: cytoskeletal disruption, potassium efflux, transbilayer phospholipid migration, and membrane disordering. The calcium ionophore, ionomycin, disrupted the actin cytoskeleton of S49 lymphoma cells and produced rapid release of microparticles. This release was significantly inhibited by interventions that impaired calcium-activated potassium current. Microparticle release was also greatly reduced in a lymphocyte cell line deficient in the expression of scramblase, the enzyme responsible for calcium-stimulated dismantling of the normal phospholipid transbilayer asymmetry. Rescue of the scrambling function at high ionophore concentration also resulted in enhanced particle shedding. The effect of membrane physical properties was addressed by varying the experimental temperature (32-42°C). A significant positive trend in the rate of microparticle release as a function of temperature was observed. Fluorescence experiments with trimethylammonium diphenylhexatriene and Patman revealed significant decrease in the level of apparent membrane order along that temperature range. These results demonstrated that biophysical mechanisms involved in microparticle release from platelets and erythrocytes apply also to lymphocytes.

Decreased calcium pump expression in human erythrocytes is connected to a minor haplotype in the ATP2B4 gene.

Science.gov (United States)

Zámbó, Boglárka; Várady, György; Padányi, Rita; Szabó, Edit; Németh, Adrienn; Langó, Tamás; Enyedi, Ágnes; Sarkadi, Balázs

2017-07-01

Plasma membrane Ca 2+ -ATPases are key calcium exporter proteins in most tissues, and PMCA4b is the main calcium transporter in the human red blood cells (RBCs). In order to assess the expression level of PMCA4b, we have developed a flow cytometry and specific antibody binding method to quantitatively detect this protein in the erythrocyte membrane. Interestingly, we found several healthy volunteers showing significantly reduced expression of RBC-PMCA4b. Western blot analysis of isolated RBC membranes confirmed this observation, and indicated that there are no compensatory alterations in other PMCA isoforms. In addition, reduced PMCA4b levels correlated with a lower calcium extrusion capacity in these erythrocytes. When exploring the potential genetic background of the reduced PMCA4b levels, we found no missense mutations in the ATP2B4 coding regions, while a formerly unrecognized minor haplotype in the predicted second promoter region closely correlated with lower erythrocyte PMCA4b protein levels. In recent GWA studies, SNPs in this ATP2B4 haplotype have been linked to reduced mean corpuscular hemoglobin concentrations (MCHC), and to protection against malaria infection. Our data suggest that an altered regulation of gene expression is responsible for the reduced RBC-PMCA4b levels that is probably linked to the development of human disease-related phenotypes. Copyright © 2017 Elsevier Ltd. All rights reserved.

EFEK PEMBERIAN ANTIOKSIDAN TOKOFEROL ALFA TERHADAP MEMBRAN SEL DARAH MERAH TALASEMIA

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Ferry P Gultom

2015-09-01

Full Text Available Talasemia is blood disorder which is characterized by anemia due to inherited haemoglobine disorder. The anemia is caused by a decreased flexibility of the erythrocyte results in decreased capability of required deformability to be able to across through capillary blood vessels. Free radicals with one or more unpaired electron on potential in destroying all the molecule exist in the body of living things like protein, carbohydrate and fat. Tocoferol or vitamin E is an antioxidant essential in eliminating free radicals in the cell membrane by inhibiting the peroxidation process of the cell membrane lipid. The objective of this study is to investigate the severity of the erythrocyte destruction either those with or without oxidative load from the environment. The results of this study showed that the level of malondialdehid in the control of erythrocyte was 1.85 ± 1.37 nmol in talasemia and 1.02 ± 0.64 nmol in normal (p<0.05. The addition of 2mM t-BHP resulted in increased malondialdehid level up to 19.59 ± 6.82 nmol in talasemia and 11.42 ± 3.49 nmol in normal erythrocytes (P<0.05. Oxidated erythrocyte with vitamin E supplement beforehand showed lower level of malondialdehid composed to those without vitamin E supplement (p<0.05. Conclusion: Additional vitamin E (tocoferol leads to decreased level of malondialdehid both in the normal and thalasemia erythrocytes.

Dielectric inspection of erythrocyte morphology

International Nuclear Information System (INIS)

Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio; Asami, Koji

2008-01-01

We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes

Dielectric inspection of erythrocyte morphology

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Yoshihito; Oshige, Ikuya; Katsumoto, Yoichi; Omori, Shinji; Yasuda, Akio [Life Science Laboratory, Materials Laboratories, Sony Corporation, Sony Bioinformatics Center, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510 (Japan); Asami, Koji [Laboratory of Molecular Aggregation Analysis, Division of Multidisciplinary Chemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)], E-mail: Yoshihito.Hayashi@jp.sony.com

2008-05-21

We performed a systematic study of the sensitivity of dielectric spectroscopy to erythrocyte morphology. Namely, rabbit erythrocytes of four different shapes were prepared by precisely controlling the pH of the suspending medium, and their complex permittivities over the frequency range from 0.1 to 110 MHz were measured and analyzed. Their quantitative analysis shows that the characteristic frequency and the broadening parameter of the dielectric relaxation of interfacial polarization are highly specific to the erythrocyte shape, while they are insensitive to the cell volume fraction. Therefore, these two dielectric parameters can be used to differentiate erythrocytes of different shapes, if dielectric spectroscopy is applied to flow-cytometric inspection of single blood cells. In addition, we revealed the applicability and limitations of the analytical theory of interfacial polarization to explain the experimental permittivities of non-spherical erythrocytes.

Effects of ionizing radiation and steady magnetic field on erythrocytes

International Nuclear Information System (INIS)

Ivanov, S. P.; Galutzov, B. P.; Kuzmanova, M. A.; Markov, M. S.

1996-01-01

A complex biophysical test for studying the effects of ionizing and non-ionizing radiation has been developed. The following cell and membrane parameters have been investigated: cell size, cell shape, cell distribution by size, electrophoretic mobility, extent of hemolysis, membrane transport and membrane impedance. Gamma ray doses of 2.2 Gy and 3.3 Gy were used as ionizing radiation and steady (DC) magnetic field of 5-90 mT representing the non-ionizing radiation. Erythrocytes from humans and rats were exposed in vitro to both ionizing and non-ionizing radiation. In some experiments ionizing radiation was applied in vivo as well. Each of the simultaneously studied parameters have been found to change as a function of applied radiation. The proposed test allows an estimation of the changes in the elastic, rheological and electrical parameters of cells and biological membranes. Results indicate that ionizing radiation is significantly more effective in an in vivo application, while magnetic fields are more effective when applied in vitro. Surprisingly, steady magnetic fields were found to act as protector against some harmful effects of ionizing radiation. (authors)

[Dynamics of bioelectric activity of the brain and erythrocyte ultrastructure after intravenous infusion of sodium bicarbonate to oncologic patients].

Science.gov (United States)

Davydova, I G; Kassil', V L; Raĭkhlin, N T; Filippova, N A

1992-04-01

23 patients with malignant tumors of different location and histogenesis were investigated. There were no metastases in 9 cases. 10 patients had metastases in regional areas and 4--distant. The results were compared with those obtained in 4 patients with nonmalignant diseases. EEG, blood gases, plasma acid--base balance and ultrastructure of erythrocytes were explored before and after intravenous infusion of 4.2% sodium bicarbonate solution. The metabolic alkalosis induced amelioration of EEG, which was changed basically, the condense of pre-membrane layer disappeared or decreased in erythrocytes, and disaggregation of erythrocytes took place in cancer patients vs those with nonmalignant tumors. The results confirm the suggestion of generalized intracellular acidosis in malignant tumor patients. This acidosis can be temporarily avoided or diminished artificially by blood alkalosis.

[Scanning electron microscopy of peripheral blood erythrocytes in the diagnosis and treatment of hemorrhagic vasculitis in children].

Science.gov (United States)

Nagaeva, T A; Balasheva, I I; Saratikov, A S; Bocharova, M N; Mikhalenko, A N

2001-01-01

Twenty-four children aged 3-15 years were examined, 16 of these with cutaneous and articulo-cutaneous hemorrhagic vasculitis (HV) and 8 normal controls. The patients were divided into 2 groups: 10 patients treated by basic therapy and 6 children whose treatment protocols were supplemented by membranoprotector locheine. The children were repeatedly examined 1 month after discharge from hospital. Scanning electron microscopy of peripheral blood erythrocytes provides valuable diagnostic data on erythrocyte membrane morphology and function in children with HV and can serve as a method for monitoring the efficiency of new approaches to therapy of this disease.

Fundamental studies on the insulin receptor in rabbit erythrocytes

Energy Technology Data Exchange (ETDEWEB)

Shinomiya, Y; Kagawa, S; Konishi, Y; Morimoto, H; Tsumura, Y [Hyogo Medical Coll. (Japan)

1975-09-01

The authors studied the binding of insulin to rabbit erythrocytes as a mode case in the hope of characterizing the physiologic role of the binding of insulin to receptor in both normal adults and patients. Specific binding sites for insulin were detected in rabbit erythrocytes. The characteristics of the binding were similar to those observed in other target tissues. The specific binding of /sup 125/I-labeled insulin was competitively inhibited by a small amount of unlabeled insulin and was completely inhibited by 1,000 ng/ml of unlabeled insulin. Glucagon, however, had no effect on the insulin binding to fat cells or liver membranes nor had it any effect on the binding of insulin to rabbit erythrocytes. Scatchard analysis of this binding reaction indicated two different binding sites with Ksub(aff)=3.2 x 10/sup 8//M, Ksub(diss)=3.1 x 10/sup -9/M; Ksub(aff)=1.4 x 10/sup 8//M, Ksub(diss)=7.1 x 10/sup -9/M respectively, and the binding capacities of each site were estimated at 0.011 ng/4 x 10/sup 8/ cells and 0.138 ng/4 x 10/sup 8/ cells. The binding of /sup 125/I-insulin to rabbit erythrocytes was a saturable function of the insulin concentration and was a linear function of cell concentration. The pH optimum for the reaction was 7.4 at 0/sup 0/C, the amount of insulin binding increased continuously under the reaction and this binding reaction reached a steady state after 10 to 15hr. On the other hand, the specific binding of insulin at higher temperatures showed maximal amounts after 20 to 30 min. and subsequently fell off at later time points.

The effects of Ankaferd® Blood Stopper on transcription factors in HUVEC and the erythrocyte protein profile

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Erkan Yılmaz

2011-12-01

Full Text Available Objective: Ankaferd® Blood Stopper (ABS is an herbal extract that has historically been used as a hemostatic agent in traditional Turkish medicine. ABS is comprised of a standardized herbal mixture of T. vulgaris, G. glabra, V. vinifera, A. officinarum, and U. dioica. ABS’s basic mechanism of action is the formation of an encapsulated protein web, which represents the focal point for vital erythrocyte masses. The hemostatic effects of ABS have been observed in vitro and in vivo. ABS was registered as a hemostatic agent for external hemorrhages and dental bleeding following phase I randomized, double-blind crossover placebo-controlled clinical research, and safety and efficacy reports. In terms of the potential use of ABS, transcription factors may be novel factors that play a role in the hemostatic and other pleiotropic effects of ABS. Materials and Methods: Hence, the present study aimed to investigate the effects of ABS on endothelium, and possible transcription factor changes in HUVEC (human umbilical vein endothelial cells and the erythrocyte membrane profile. ABS (5 μL and 50 μL was administered to HUVEC (in 75 cm2; ~75% fullness for 5 min and 15 min. Results: ABS caused significant increases in the level of activation of the following transcription factors; AP2, AR, CRE/ATF1, CREB, E2F1-5, E2F6, EGR, GATA, HNF-1, ISRE, Myc-Max, NF-1, NFkB, p53, PPAR, SMAD 2/3, SP1, TRE/AP1, and YY1. Following erythrocyte membrane isolation, protein complexes were undissolved, but denatured. The protein complex formed was resistant to heat and detergent. Trypsin and sonication were used in order to break this complex; the complex dissolved and erythrocyte membrane proteins were released in SDS-PAGE.Conclusion: ABS established a very fast and solid protein web, and increased the level of transcription factor activation. Therefore the cellular effects of ABS could be related to different intracellular biological pathways.

Monoclonal antibody OKM5 inhibits the in vitro binding of Plasmodium falciparum-infected erythrocytes to monocytes, endothelial, and C32 melanoma cells

International Nuclear Information System (INIS)

Barnwell, J.W.; Ockenhouse, C.F.; Knowles, D.M. II

1985-01-01

Plasmodium falciparum-infected erythrocytes bind in vitro to human endothelial cells, monocytes, and a certain melanoma cell line. Evidence suggests that this interaction is mediated by similar mechanisms which lead to the sequestration of parasitized erythrocytes in vivo through their attachment to endothelial cells of small blood vessels. They show here the monoclonal antibody OKM5, previously shown to react with the membranes of endothelial cells, monocyte,s and platelets, also reacts with the C32 melanoma cell line which also binds P. falciparum-infected erythrocytes. At relatively low concentrations, OKM5 inhibits and reverses the in vitro adherence of infected erythrocytes to target cells. As with monocytes, OKM5 antibody recognizes an 125 I-labeled protein of approximately 88 Kd on the surface of C32 melanoma cells. It seems likely, therefore, that the 88 Kd polypeptide plays a role in cytoadherence, possibly as the receptor or part of a receptor for a ligand on the surface of infected erythrocytes

Plasma lipid pattern and red cell membrane structure in β-thalassemia patients in Jakarta

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Seruni K.U. Freisleben

2011-08-01

Full Text Available Background: Over the last 10 years, we have investigated thalassemia patients in Jakarta to obtain a comprehensive picture of iron overload, oxidative stress, and cell damage.Methods: In blood samples from 15 transfusion-dependent patients (group T, 5 non-transfused patients (group N and 10 controls (group C, plasma lipids and lipoproteins, lipid-soluble vitamin E, malondialdehyde (MDA and thiol status were measured. Isolated eryhtrocyte membranes were investigated with electron paramagnetic resonance (EPR spectroscopy using doxyl-stearic acid and maleimido-proxyl spin lables. Data were analyzed statistically with ANOVA.Results: Plasma triglycerides were higher and cholesterol levels were lower in thalassemic patients compared to controls. Vitamin E, group C: 21.8 vs T: 6.2 μmol/L and reactive thiols (C: 144 vs. T: 61 μmol/L were considerably lower in transfused patients, who exert clear signs of oxidative stress (MDA, C: 1.96 vs T: 9.2 μmol/L and of tissue cell damage, i.e., high transaminases plasma levels. Non-transfused thalassemia patients have slight signs of oxidative stress, but no significant indication of cell damage. Erythrocyte membrane parameters from EPR spectroscopy differ considerably between all groups. In transfusion-dependent patients the structure of the erythrocyte membrane and the gradients of polarity and fluidity are destroyed in lipid domains; binding capacity of protein thiols in the membrane is lower and immobilized.Conclusion: In tranfusion-dependent thalassemic patients, plasma lipid pattern and oxidative stress are associated with structural damage of isolated erythrocyte membranes as measured by EPR spectroscopy with lipid and proteinthiol spin labels. (Med J Indones 2011; 20:178-84Keywords: electron paramagnetic resonance spectroscopy, erythrocyte membrane, lipoproteins, oxidative stress, thalassemia, plasma lipids.

Effects of proteolytic enzymes and neuraminidase on the I and i erythrocyte antigen sites

International Nuclear Information System (INIS)

Doinel, C.; Ropars, C.; Salmon, C.

1978-01-01

Homogeneous cold agglutinins, purified and labelled with 125 I, have been used in a study of the effects of neuraminidase and proteolytic enzymes on the I and i reactivities of human adult erythrocytes. Measurements were made of antigen site numbers, equilibrium constants and thermodynamic parameters. There was enhanced reactivity after enzyme treatment as well as after the release of N-acetylneuraminic acid. Steric factors were shown to be of primary importance in the accessibility of the I and i antigenic determinant. After enzyme treatment, the antigenic structures became more homogeneous in their reaction with antibodies. The heterogeneity of binding constants observed with antigenic determinants of non-treated erythrocytes is probably due to the wide range of spatial distribution of these receptors within the membrane. (author)

Different kinetic in incorporation and depletion of n-3 fatty acids in erythrocytes and leukocytes of mice

DEFF Research Database (Denmark)

Mu, Huiling; Thogersen, Regitze Louise; Maaetoft-Udsen, Kristina

2006-01-01

during a 6-wk feeding period. Over the first 3-wk period (the incorporation period) the mice were fed a special diet with a high n-3/n-6 PUFA ratio. In the following 3-wk period (the depletion period) the mice were fed a standard chow diet. A linear increase of the concentration of EPA and DHA...... in erythrocyte membranes was observed during the incorporation period, whereas a stagnation was observed after the second week for leukocytes. The level of EPA did not fall to the background level after the depletion period, and the level of DHA was kept almost constant during the depletion period...... in the erythrocyte membranes. In leukocytes the concentration of both EPA and DHA decreased during the depletion period, but did not reach the background level after the 3-wk depletion. In conclusion, the kinetics of EPA and DHA in the different cells are different. The rate of incorporation is faster than...

Selective association of a fragment of the knob protein with spectrin, actin and the red cell membrane.

Science.gov (United States)

Kilejian, A; Rashid, M A; Aikawa, M; Aji, T; Yang, Y F

1991-02-01

The knob protein of Plasmodium falciparum is essential for the formation of knob-like protrusions on the host erythrocyte membrane. A functional domain of the knob protein was identified. This peptide formed stable complexes with the two major red cell skeletal proteins, spectrin and actin. When introduced into resealed normal erythrocytes, the peptide associated selectively with the cytoplasmic surface of the membrane and formed knob-like electron dense deposits. Knobs are thought to play an important role in the immunopathology of P. falciparum infections. Our findings provide a first step towards understanding the molecular basis for selective membrane changes at knobs.

Protein 4.1, a component of the erythrocyte membrane skeleton and its related homologue proteins forming the protein 4.1/FERM superfamily.

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Aleksander F Sikorski

2007-01-01

Full Text Available The review is focused on the domain structure and function of protein 4.1, one of the proteins belonging to the membrane skeleton. The protein 4.1 of the red blood cells (4.1R is a multifunctional protein that localizes to the membrane skeleton and stabilizes erythrocyte shape and membrane mechanical properties, such as deformability and stability, via lateral interactions with spectrin, actin, glycophorin C and protein p55. Protein 4.1 binding is modulated through the action of kinases and/or calmodulin-Ca2+. Non-erythroid cells express the 4.1R homologues: 4.1G (general type, 4.1B (brain type, and 4.1N (neuron type, and the whole group belongs to the protein 4.1 superfamily, which is characterized by the presence of a highly conserved FERM domain at the N-terminus of the molecule. Proteins 4.1R, 4.1G, 4.1N and 4.1B are encoded by different genes. Most of the 4.1 superfamily proteins also contain an actin-binding domain. To date, more than 40 members have been identified. They can be divided into five groups: protein 4.1 molecules, ERM proteins, talin-related molecules, protein tyrosine phosphatase (PTPH proteins and NBL4 proteins. We have focused our attention on the main, well known representatives of 4.1 superfamily and tried to choose the proteins which are close to 4.1R or which have distinct functions. 4.1 family proteins are not just linkers between the plasma membrane and membrane skeleton; they also play an important role in various processes. Some, such as focal adhesion kinase (FAK, non-receptor tyrosine kinase that localizes to focal adhesions in adherent cells, play the role in cell adhesion. The other members control or take part in tumor suppression, regulation of cell cycle progression, inhibition of cell proliferation, downstream signaling of the glutamate receptors, and establishment of cell polarity; some are also involved in cell proliferation, cell motility, and/or cell-to-cell communication.

Comparison of plasma and erythrocyte membrane fatty acid compositions in patients with end-stage renal disease and type 2 diabetes mellitus.

Science.gov (United States)

Sertoglu, Erdim; Kurt, Ismail; Tapan, Serkan; Uyanik, Metin; Serdar, Muhittin A; Kayadibi, Huseyin; El-Fawaeir, Saad

2014-02-01

In this study, we aimed to compare the serum lipid profile and fatty acid (FA) compositions of erythrocyte membrane (EM) and plasma in three different patient groups (group 1: type 2 diabetes mellitus (T2DM)+end-stage renal disease (ESRD), group 2: ESRD, group 4: T2DM) and healthy controls (group 3) simultaneously. 40 ESRD patients treated with hemodialysis (HD) in Gulhane School of Medicine (20 with T2DM) and 32 controls (17 with T2DM, 15 healthy controls) were included in the study. Plasma and EM FA concentrations were measured by gas chromatography-flame ionization detector (GC-FID). Plasma and EM palmitic acid (PA) and stearic acid (SA) levels were significantly higher in T2DM patients compared to controls (p=0.040 and p=0.002 for plasma, p=0.001 and p=0.010 for EM, respectively). EM docosahexaenoic acid (DHA) levels were also significantly lower in patients with ESRD+T2DM and ESRD compared to controls (p=0.004 and p=0.037, respectively). Patients with insulin resistance display a pattern of high long chain saturated FAs (PA, SA and arachidic acids). However, while there are no recognized standards for normal EM DHA content, decreased levels of EM DHA in ESRD patient groups (groups 1 and 2) suggest that there may be reduced endogenous synthesis of DHA in HD subjects, due to the decreased functionality of desaturase and elongase enzymes. Because membrane PUFA content affects membrane fluidity and cell signaling, these findings are worthy of further investigation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The modulation of erythrocyte Na+/K+-ATPase activity by curcumin

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Prabhakar Singh

2015-11-01

Full Text Available Curcumin, an active biphenolic molecule present in turmeric (Curcuma longa, has been reported to elicit plethora of health protective effects. The present study was carried out in vitro, in vivo and in silico to investigate the modulatory effects of curcumin on erythrocyte membrane Na+/K+-ATPase activity. In vitro curcumin (10−5 M to 10−8 M was incubated with human erythrocytes membrane. In vivo curcumin (340 mg/kg b.w. and 170 mg/kg b.w. was supplemented to wistar rats for 21 days. In silico, catalytic unit α of Na+/K+-ATPase (3b8e.pdb protein was used as a receptor for the natural ligand ATP to study curcumin-mediated docking simulation using AutoDock4. The in vitro effect of curcumin on the Na+/K+-ATPase activity in human erythrocytes was biphasic. An inhibitory response was observed at 10−5 M (p < 0.001. An activation of the Na+/K+-ATPase activity was observed at 10−7 and 10−8 M (p < 0.001 and p < 0.01. In vivo, curcumin supplementation to rats increased the Na+/K+-ATPase activity at doses 340 mg/kg b.w. (p < 0.001 as well as at 170 mg/kg b.w., (p < 0.01. AutoDock4 docking simulation study showed that both ligands curcumin and ATP actively interacted with amino acids Glu214, Ser215, Glu216, Thr371, Asn377, Arg378, Met379, Arg438, Val440, Ala444, Lys451 and Asp586 at the catalytic cavity of Na+/K+-ATPase. ATP had more H bonding and hydrophobic interaction with active site amino acid residues compared to curcumin. These finding may explain some of the health beneficial properties of curcumin associated with deregulated Na+/K+-ATPase activity or ions homeostasis.

Contribution of ankyrin-band 3 complexes to the organization and mechanical properties of the membrane skeleton of human erythrocyte

Energy Technology Data Exchange (ETDEWEB)

Shen, B.W. [Argonne National Lab., IL (United States). Biological and Medical Research Div.

1995-02-01

To understand the role of ankyrin-band 3 complexes in the organization of the spectrin-based membrane skeleton and its contribution to the mechanical properties of human erythrocytes, intact skeletons and single-layered skeleton leaflets were prepared from intact and physically sheared membrane ghosts, expanded in low salt buffer, and examined by transmission electron microscopy. While the structures of intact skeletons and single-layered skeleton leaflets shared many common features, including rigid junctional complexes of spectrin, actin, and band 4.1; short stretches ({approximately}50 {angstrom}) of flexible spectrin filaments; and globular masses of ankyrin-band 3 complexes situated close to the middle of the spectrin filaments, the definition of structural units in the intact skeleton is obscured by the superposition of the two layers. However, the spatial disposition of structural elements can be clearly defined in the images of the single-layered skeleton leaflets. Partially expanded skeletal leaflets contain conglomerates of ankyrin-band 3 complexes arranged in a circular or clove-leaf configuration that straddles multiple strands of thick spectrin cables, presumably reflecting the association of ankyrin-band 3 complexes on neighboring spectrin tetramers as well as the lateral association of the spectrin filaments. Hyperexpansion of the skeleton leaflets led to dissociation of the conglomerates of ankyrin-band 3 complexes, full-extension of the spectrin tetramers, and separation of the individual strands of spectrin tetramers. Clearly defined stands of spectrin tetramers in the hyperexpanded single-layered skeletal leaflets often contained two sets of globular protein masses that divided the spectrin tetramers into three segments of approximately equal length.

Breakdown of Phosphatidylserine Asymmetry Following Treatment of Erythrocytes with Lumefantrine

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Kousi Alzoubi

2014-02-01

Full Text Available Background: Lumefantrine, a commonly used antimalarial drug, inhibits hemozoin formation in parasites. Several other antimalarial substances counteract parasitemia by triggering suicidal death or eryptosis of infected erythrocytes. Eryptosis is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine-exposure at the erythrocyte surface. Signaling involved in eryptosis include increase of cytosolic Ca2+-activity ([Ca2+]i, formation of ceramide, oxidative stress and/or activation of p38 kinase, protein kinase C (PKC, or caspases. The present study explored, whether lumefantrine stimulates eryptosis. Methods: Cell volume has been estimated from forward scatter, phosphatidylserine-exposure from annexin V binding, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species from 2',7'-dichlorodihydrofluorescein-diacetate fluorescence, content of reduced glutathione (GSH from mercury orange fluorescence, and ceramide abundance from binding of fluorescent antibodies in flow cytometry. Results: A 48 h exposure to lumefantrine (3 µg/mL was followed by a significant increase of annexin-V-binding without significantly altering forward scatter, [Ca2+]i, ROS formation, reduced GSH, or ceramide abundance. The annexin-V-binding following lumefantrine treatment was not significantly modified by p38 kinase inhibitors SB203580 (2 μM and p38 Inh III (1 μM, PKC inhibitor staurosporine (1 µM or pancaspase inhibitor zVAD (1 or 10 µM. Conclusions: Lumefantrine triggers cell membrane scrambling, an effect independent from entry of extracellular Ca2+, ceramide formation, ROS formation, glutathione content, p38 kinase, PKC or caspases.

Diffusion properties of band 3 in human erythrocytes

Science.gov (United States)

Spector, Jeffrey O.

The plasma membrane of the human erythrocyte (RBC) is a six fold symmetric network held together at various pinning points by several multi-protein complexes. This unique architecture is what gives the RBC its remarkable material properties and any disruptions to the network can have severe consequences for the cell. Band 3 is a major transmembrane protein that plays the role of linking the fluid lipid bilayer to the cytoskeletal network. To interrogate the structural integrity of the RBC membrane we have tracked individual band 3 molecules in RBCs displaying a variety of pathologies that are all a consequence of membrane or network related defects. These diseases are spherocytosis, elliptocytosis, and pyropokilocytosis. We have also investigated the protein related diseases sickle cell, and south east asian ovalocytosis. To assess the impact that the network has on the dynamic organization of the cell we have also studied the mobility of band 3 in RBC progenitor cells. Individual band 3 molecules were imaged at 120 frames/second and their diffusion coefficients and compartment sizes recorded. The distributions of the compartment sizes combined with the information about the short and long time diffusion of band 3 has given us insight into the architecture of the membrane in normal and diseased cells. The observation that different membrane pathologies can be distinguished, even to the point of different molecular origins of the same disease, implies that the mobility of transmembrane proteins may be a useful tool for characterizing the "health" of the membrane.

Irregular Distortion of The Erythrocytes (Acanthocytes, Spur Cells in Senile Dementia

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H. B. Goodall

1994-01-01

Full Text Available An excess of irregularly di storted red cells with spiked forms (acanthocytes. spur cells has been found in a substantial minority of patient s with seni le dementia of Alzheimer type (7 of 50 patients, 3 of 21 men and 4 of 29 women. Of 100 control patients, 42 men and 58 women, 5 (men and 2 women showed comparable distortion, but, of these, one man may well have incipient dementia and the others had serious organic di seases which may be associated with comparable erythrocytic changes. The cause of the distortion is not yet clear, but the presence of occasional giant erythrocytes in the absence of general macrocytosis suggests a possible abnormality of cell membrane synthes is. This distortion may be a useful marker in patients with loss of memory. Whether it is a manifestation of a haemopoietic clone or a constitutional anomaly associated with Alzheimer’s disease remains to be seen.

Demonstration of specific binding sites for 3H-RRR-alpha-tocopherol on human erythrocytes

International Nuclear Information System (INIS)

Kitabchi, A.E.; Wimalasena, J.

1982-01-01

Previous work from our laboratory demonstrated specific binding sites for 3 H-RRR-alpha-tocopherol ( 3 H-d alpha T) in membranes of rat adrenal cells. As tocopherol deficiency is associated with increased susceptibility of red blood cells to hemolysis, we investigated tocopherol binding sites in human RBCs. Erythrocytes were found to have specific binding sites for 3 H-d alpha T that exhibited saturability and time and cell-concentration dependence as well as reversibility of binding. Kinetic studies of binding demonstrated two binding sites--one with high affinity (Ka of 2.6 x 10(7) M-1), low capacity (7,600 sites per cell) and the other with low affinity (1.2 x 10(6) M-1), high capacity (150,000 sites per cell). In order to localize the binding sites further, RBCs were fractionated and greater than 90% of the tocopherol binding was located in the membranes. Similar to the findings in intact RBCs, the membranes exhibited two binding sites with a respective Ka of 3.3 x 10(7) M-1 and 1.5 x 10(6) M-1. Specificity data for binding demonstrated 10% binding for RRR-gamma-tocopherol, but not other tocopherol analog exhibited competition for 3 H-d alpha T binding sites. Instability data suggested a protein nature for these binding sites. Preliminary studies on Triton X-100 solubilized fractions resolved the binding sites to a major component with an Mr of 65,000 and a minor component with an Mr of 125,000. We conclude that human erythrocyte membranes contain specific binding sites for RRR-alpha-tocopherol. These sites may be of physiologic significance in the function of tocopherol on the red blood cell membrane

Whole body gamma radiation effects on rheological behaviour (deformability) of rat erythrocytes

International Nuclear Information System (INIS)

Soliman, M.S.

2004-01-01

This study was designed to determine the effect of whole body gamma irradiation on the rheological behaviour of rat erythrocytes (deformability). Animals were divided into 4 irradiated groups and 4 control groups according to their sacrificing time intervals (1 st, 3 rd, 5 th and 7 th days) post-irradiation with dose (6 Gy). In all animals and at the previous time intervals, red blood cell (RBC) membrane proteins electrophoretic pattern, RBC membrane lipids levels (cholesterol and phospholipids), RBC electrolytes levels (sodium, potassium and calcium), corpuscular osmotic fragility and RBC morphological by scanning electron microscopy were determined. Highly significant increase in membrane cholesterol, RBC sodium, calcium and corpuscular osmotic fragility accompanied by highly significant decrease in membrane phospholipids, RBC potassium and RBC deformability were found. No changes in membrane proteins electrophoretic patterns were detected. Morphologically, there were increase in the incidences of echinocytes and spherocytes development, which were time dependent. According to the previous results, irradiation promotes alterations in RBC shape (echinocytosis), membrane skeletal dysfunction, membrane lipid peroxidation, increase in membrane cholesterol/phospholipid content, changes in membrane electrolyte permeability and decrease then increase in osmotic fragility. These alterations in turn led to decrease in cellular deformability as a result of increased membrane rigidity and also due to cells dehydration caused by excess leakage of potassium ions from the RBCs

Protective effect of Opuntia ficus indica f. inermis prickly pear juice upon ethanol-induced damages in rat erythrocytes.

Science.gov (United States)

Alimi, Hichem; Hfaeidh, Najla; Bouoni, Zouhour; Sakly, Mohsen; Ben Rhouma, Khémais

2012-05-01

Juice from the fruit of the cactus Opuntia ficus indica is claimed to possess several health-beneficial properties. The present study was carried out to determine whether O. ficus indica f. inermis fruit extract might have a protective effect upon physiological and morphological damages inflicted to erythrocytes membrane by chronic ethanol poisoning, per os, in rat. Chemical analysis of the extract revealed the presence of polyphenols, flavonoids, ascorbic acid, carotenoids, and betalains. Ethanol administration (3 g/kg b.w, per day for 90 days) induced an increase of malondialdehyde (MDA) and carbonylated proteins levels and a decrease of glutathione (GSH) level in erythrocyte. Ethanol administration also reduced the scavenging activity in plasma and enhanced erythrocytes hemolysis, as compared to control rats. In addition, ethanol intake increased the erythrocyte shape index by +895.5% and decreased the erythrocyte diameter by -61.53% as compared to controls. In animals also given prickly pear juice during the same experimental period, the studied parameters were much less shifted. This protective effect was found to be dose-dependent. It is likely that the beneficial effect of the extract is due to the high content of antioxidant compounds. Copyright © 2012 Elsevier Inc. All rights reserved.

Multiple extrafoveal macular holes following internal limiting membrane peeling

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Hussain N

2018-05-01

Full Text Available Nazimul Hussain, Sandip Mitra Department of Ophthalmology, Al Zahra Hospital, Sharjah, United Arab Emirates Objective: Internal limiting membrane (ILM peeling has been the standard of treatment for macular holes. Besides, causing retinal nerve fiber layer surface abnormality, postoperative extrafoveal multiple retinal holes is a rare phenomenon following ILM peeling. We report an unusual complication of eight extrafoveal macular holes occurring following ILM peeling.Case presentation: A 60-year-old male presented with complaints of decreased and distorted vision in the right eye. He was diagnosed as having epiretinal membrane with lamellar macular hole. He underwent 23G pars plana vitrectomy, brilliant blue assisted ILM peeling and fluid gas exchange. Intraoperatively, ILM was found to be adherent to the underlying neurosensory retina. One month after cataract surgery, he underwent YAG capsulotomy in the right eye. He complained of visual distortion. His fundus evaluation in the right eye showed multiple (eight extrafoveal retinal holes temporal to the macula clustered together.Conclusion: This case demonstrated that peeling of ILM, especially when it is adherent to the underlying neurosensory retina, may cause unwanted mechanical trauma to the inner retina. Glial apoptosis and neuronal degeneration may presumably play a role in delayed appearance of multiple (eight extrafoveal macular holes, which has not been reported earlier. Keywords: internal limiting membrane, lamellar macular hole, full thickness macular holes, epiretinal membrane

[Ceruloplasmin receptor on human erythrocytes].

Science.gov (United States)

Saenko, E L; Basevich, V V; Iaropolov, A I

1988-08-01

The structural fragments of the human ceruloplasmin (CP) molecule and of erythrocyte receptors which provide for the specific interaction of CP with erythrocytes were identified, and their properties were investigated. The interaction of CP with erythrocytes, both intact and treated with neuroaminidase and proteolytic enzymes (trypsin, chymotrypsin, papaine, pronase E) is described. Experiments with CP reception were performed at 4 degrees C, using [125I]CP and [125I]asialo-CP. The parameters of binding were determined in Scatchard plots. It was demonstrated that the specific binding of CP to erythrocyte receptors is determined by its interaction with two structural sites of the carbohydrate moiety of the CP molecule, i.e., the terminal residues of sialic acids and a site, (formula; see text) located at a large distance from the chain terminus.

Investigations into the binding of 125I-calmodulin to CA++ transport ATPase of human erythrocytes

International Nuclear Information System (INIS)

Sterk, V.

1983-01-01

The study described was carried out in order to investigate the binding of 125 I-calmodulin to Ca ++ transport ATPase using different Ca ++ concentrations and temperatures. The data obtained from these experiments were subsequently analysed in such as a way as to yield meaningful information relating to the mechanisms underlying the attachment of calmodulin to Ca ++ transport ATPase, the % proportion of membrane protein that was attributable to the enzyme as well as the number of calmodulin receptor sites on the individual erythrocytes, etc. Comparisons with data from the relevant literature permitted conclusions to be drawn concerning the mode of Ca ++ transport at the level of the erythrocytes. A new methodology and processing technique had to be developed prior to the beginning of the experiments. (orig./MG) [de

In-Depth, Label-Free Analysis of the Erythrocyte Cytoplasmic Proteome in Diamond Blackfan Anemia Identifies a Unique Inflammatory Signature.

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Esther N Pesciotta

Full Text Available Diamond Blackfan Anemia (DBA is a rare, congenital erythrocyte aplasia that is usually caused by haploinsufficiency of ribosomal proteins due to diverse mutations in one of several ribosomal genes. A striking feature of this disease is that a range of different mutations in ribosomal proteins results in similar disease phenotypes primarily characterized by erythrocyte abnormalities and macrocytic anemia, while most other cell types in the body are minimally affected. Previously, we analyzed the erythrocyte membrane proteomes of several DBA patients and identified several proteins that are not typically associated with this cell type and that suggested inflammatory mechanisms contribute to the pathogenesis of DBA. In this study, we evaluated the erythrocyte cytosolic proteome of DBA patients through in-depth analysis of hemoglobin-depleted erythrocyte cytosols. Simple, reproducible, hemoglobin depletion using nickel columns enabled in-depth analysis of over 1000 cytosolic erythrocyte proteins with only moderate total analysis time per proteome. Label-free quantitation and statistical analysis identified 29 proteins with significantly altered abundance levels in DBA patients compared to matched healthy control donors. Proteins that were significantly increased in DBA erythrocyte cytoplasms included three proteasome subunit beta proteins that make up the immunoproteasome and proteins induced by interferon-γ such as n-myc interactor and interferon-induced 35 kDa protein [NMI and IFI35 respectively]. Pathway analysis confirmed the presence of an inflammatory signature in erythrocytes of DBA patients and predicted key upstream regulators including mitogen activated kinase 1, interferon-γ, tumor suppressor p53, and tumor necrosis factor. These results show that erythrocytes in DBA patients are intrinsically different from those in healthy controls which may be due to an inflammatory response resulting from the inherent molecular defect of ribosomal

Extracellular histones induce erythrocyte fragility and anemia.

Science.gov (United States)

Kordbacheh, Farzaneh; O'Meara, Connor H; Coupland, Lucy A; Lelliott, Patrick M; Parish, Christopher R

2017-12-28

Extracellular histones have been shown to play an important pathogenic role in many diseases, primarily through their cytotoxicity toward nucleated cells and their ability to promote platelet activation with resultant thrombosis and thrombocytopenia. In contrast, little is known about the effect of extracellular histones on erythrocyte function. We demonstrate in this study that histones promote erythrocyte aggregation, sedimentation, and using a novel in vitro shear stress model, we show that histones induce erythrocyte fragility and lysis in a concentration-dependent manner. Furthermore, histones impair erythrocyte deformability based on reduced passage of erythrocytes through an artificial spleen. These in vitro results were mirrored in vivo with the injection of histones inducing anemia within minutes of administration, with a concomitant increase in splenic hemoglobin content. Thrombocytopenia and leukopenia were also observed. These findings suggest that histones binding to erythrocytes may contribute to the elevated erythrocyte sedimentation rates observed in inflammatory conditions. Furthermore, histone-induced increases in red blood cell lysis and splenic clearance may be a significant factor in the unexplained anemias seen in critically ill patients. © 2017 by The American Society of Hematology.

The mechanism of erythrocyte sedimentation. Part 2: The global collapse of settling erythrocyte network.

Science.gov (United States)

Pribush, A; Meyerstein, D; Meyerstein, N

2010-01-01

Results reported in the companion paper showed that erythrocytes in quiescent blood are combined into a network followed by the formation of plasma channels within it. This study is focused on structural changes in the settling dispersed phase subsequent to the channeling and the effect of the structural organization on the sedimentation rate. It is suggested that the initial, slow stage of erythrocyte sedimentation is mainly controlled by the gravitational compactness of the collapsed network. The lifetime of RBC network and hence the duration of the slow regime of erythrocyte sedimentation decrease with an increase in the intercellular pair potential and with a decrease in Hct. The gravitational compactness of the collapsed network causes its rupture into individual fragments. The catastrophic collapse of the network transforms erythrocyte sedimentation from slow to fast regime. The size of RBC network fragment is insignificantly affected by Hct and is mainly determined by the intensity of intercellular attractive interactions. When cells were suspended in the weak aggregating medium, the Stokes radius of fragments does not differ measurably from that of individual RBCs. The proposed mechanism provides a reasonable explanation of the effects of RBC aggregation, Hct and the initial height of the blood column on the delayed erythrocyte sedimentation.

Transbilayer distribution and mobility of phosphatidylcholine in intact erythrocyte membranes. A study with phosphatidylcholine exchange protein

NARCIS (Netherlands)

van Meer, G.|info:eu-repo/dai/nl/068570368; Poorthuis, B.J.H.M.; Wirtz, K.W.A.|info:eu-repo/dai/nl/068427956; op den Kamp, J.A.F.; van Deenen, L.L.M.

1980-01-01

The exchange of phosphatidylcholine between intact human or rat erythrocytes and rat liver microsomes was greatly stimulated by phosphatidylcholine-specific exchange proteins from rat liver and beef liver. It was found, however, that compared to the exchange reaction between phospholipid vesicles

Erythrocyte fluorescence and lead intoxication.

Science.gov (United States)

Clark, K G

1976-01-01

Blood samples from people exposed to inorganic lead were examined by fluorescence microscopy for excess erythrocyte porphyrin. With continued lead absorption, fluorescent erythrocytes appeared in the circulation of workers handling this metal or its compounds, and they progressively increased in number and brilliance. These changes ensued if the blood lead concentration was maintained above 2-42 mumol/l (50 mug/100 ml), and preceded any material fall in the haemoglobin value. At one factory, 62-5% of 81 symptomless workers showed erythrocyte fluorescence attributable to the toxic effects of lead. Excess fluorocytes were found in blood samples from a child with pica and three of her eight siblings. These four were subsequently shown to have slightly increased blood lead concentrations (2-03 to 2-32 mumol/l). Fluorescence microscopy for excess erythrocyte porphyrin is a sensitive method for the detection of chronic lead intoxication. A relatively slight increase in the blood lead is associated with demonstrabel changes in erythrocyte porphyrin content. The procedure requires little blood, and may be performed upon stored samples collected for lead estimation. The results are not readily influenced by contamination, and provide good confirmatory evidence for the absorption of biochemically active lead. PMID:963005

Mechanism of membrane damage by El Tor hemolysin of Vibrio cholerae O1.

Science.gov (United States)

Ikigai, H; Akatsuka, A; Tsujiyama, H; Nakae, T; Shimamura, T

1996-08-01

El Tor hemolysin (ETH; molecular mass, 65 kDa) derived from Vibrio cholerae O1 spontaneously assembled oligomeric aggregates on the membranes of rabbit erythrocyte ghosts and liposomes. Membrane-associated oligomers were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting into two to nine bands with apparent molecular masses of 170 to 350 kDa. ETH assembled oligomers on a liposomal membrane consisting of phosphatidylcholine and cholesterol, but not on a membrane of phosphatidylcholine alone. Cholesterol could be replaced with diosgenin or ergosterol but not with 5alpha-cholestane-3-one, suggesting that sterol is essential for the oligomerization. The treatment of carboxyfluorescein-encapsulated liposomes with ETH caused a rapid release of carboxyfluorescein into the medium. Because dextrin 20 (molecular mass, 900 Da) osmotically protected ETH-mediated hemolysis, this hemolysis is likely to be caused by pore formation on the membrane. The pore size(s) estimated from osmotic protection assays was in the range of 1.2 to 1.6 nm. The pore formed on a rabbit erythrocyte membrane was confirmed morphologically by electron microscopy. Thus, we provide evidence that ETH damages the target by the assembly of hemolysin oligomers and pore formation on the membrane.

Erythrocyte Osmotic Fragility and Excitability Score in Rabbit fed Hibiscus Sabdariffa in Graded Level.

Science.gov (United States)

Adenkola, A Y; Oluremi, O I A

2014-12-29

This study was conducted for 10 weeks with the aim of investigating the erythrocyte membrane integrity as measured by erythrocyte osmotic fragility and excitability scores of rabbits fed graded level of Hibiscus sabdariffa calyx (HSC). Twenty weaners' rabbit of both sexes were used for the study and were placed on four experimental diets which contain the following percentages of HSC 0 %, 25 %, 50 %, 75 %, as feed additive and were added at 0 g, 62.5 g, 125 g, 187.5 g designated as T1, T2, T3 and T4 experimental diets. Excitability scores were measured weekly as described by Voisnet et al. (1997). At the end of the experiment, the rabbits were slaughtered by severing the jugular vein. A Blood sample (2 ml) was collected from each rabbit into sampled bottles, containing the Na EDTA as anticoagulant for hematological analysis. Packed cell volume (PCV) Haemoglobin concentration (Hb), Total red blood cell (RBC) count, Total leukocyte count as well as differential leukocyte was determined using standard method. The percentage haemolysis recorded at 0.3 % to 0.8 % was significantly (P < 0.05) higher in rabbits in T1 compared to the remaining 3 diets. The result of excitability score shows that rabbit on diet 1 and 2 had a lower value which was significantly (P < 0.05) lower than rabbits on diets 3 and 4 with a value of 65.5 ± 5.0 and 70.00 ± 5.50 % respectively. In conclusion this study demonstrated for the first time that chronic administration of HSC improves haematological parameters, brain mood and function as well as maintaining erythrocyte membrane integrity.

Transbilayer distribution and mobility of phosphatidylcholine in intact erythrocyte membranes. A study with phosphatidylcholine exchange protein

NARCIS (Netherlands)

van Meer, G.; Poorthuis, B. J.; Wirtz, K. W.; Op den Kamp, J. A.; van Deenen, L. L.

1980-01-01

1. The exchange of phosphatidylcholine between intact human or rat erythrocytes and rat liver microsomes was greatly stimulated by phosphatidylcholine-specific exchange proteins from rat liver and beef liver. It was found, however, that compared to the exchange reaction between phospholipid vesicles

Changes in haematology, plasma biochemistry and erythrocyte ...

African Journals Online (AJOL)

The results suggest that maintaining wild birds in captivity for a prolonged period could be stressful as shown by the heterophil/lymphocytes ratio and reduced erythrocyte osmotic resistance, and could lead to decreases in erythrocyte parameters and muscle wasting. Keywords: Haematological parameters, erythrocyte ...

Effect of phosphatidylinositol and inside-out erythrocyte vesicles on autolysis of mu- and m-calpain from bovine skeletal muscle.

Science.gov (United States)

Zalewska, Teresa; Thompson, Valery F; Goll, Darrel E

2004-08-23

The finding that phospholipid micelles lowered the Ca2+ concentration required for autolysis of the calpains led to a hypothesis suggesting that the calpains are translocated to the plasma membrane where they interact with phospholipids to initiate their autolysis. However, the effect of plasma membranes themselves on the Ca2+ concentration required for calpain autolysis has never been reported. Also, if interaction with a membrane lowers the Ca2+ required for autolysis, the membrane-bound-calpain must autolyze itself, because it would be the only calpain having the reduced Ca2+ requirement. This implies that the autolysis is an intramolecular process, although several studies have shown that autolysis of the calpains in an in vitro assay and in the absence of phospholipid is an intermolecular process. Inside-out vesicles prepared from erythrocytes had no effect on the Ca2+ concentration required for autolysis of either mu- or m-calpain, although phosphatidylinositol (PI) decreased the Ca2+ concentration required for autolysis of the same calpains. The presence of a substrate for the calpains, beta-casein, reduced the rate of autolysis of both mu- and m-calpain both in the presence and in the absence of PI, suggesting that mu- and m-calpain autolysis is an intermolecular process in the presence of PI just as it is in its absence. Because IOV have no effect on the Ca2+ concentration required for calpain autolysis, association with the plasma membrane, at least with erythrocyte plasma membranes, does not initiate calpain autolysis by reducing the Ca2+ concentration required for autolysis as suggested by the membrane-activation hypothesis. Interaction with a membrane may serve to bind calpains to their substrates rather than promoting autolysis.

Detergent-resistant membranes in human erythrocytes and their ...

Indian Academy of Sciences (India)

Unknown

SLP, stomatin-like-protein-2; TX-100, Triton X-100. ... via electrostatic interactions that can be disrupted by the simultaneous increase in pH and ionic strength of the solubilization .... dentified components of the DRMs and the membrane ..... Analysis of proteins and cholesterol in 6 ... Band 3, the main integral protein of the.

Cisplatin combined with hyperthermia kills HepG2 cells in intraoperative blood salvage but preserves the function of erythrocytes.

Science.gov (United States)

Yang, Jin-ting; Tang, Li-hui; Liu, Yun-qing; Wang, Yin; Wang, Lie-ju; Zhang, Feng-jiang; Yan, Min

2015-05-01

The safe use of intraoperative blood salvage (IBS) in cancer surgery remains controversial. Here, we investigated the killing effect of cisplatin combined with hyperthermia on human hepatocarcinoma (HepG2) cells and erythrocytes from IBS in vitro. HepG2 cells were mixed with concentrated erythrocytes and pretreated with cisplatin (50, 100, and 200 μg/ml) alone at 37 °C for 60 min and cisplatin (25, 50, 100, and 200 μg/ml) combined with hyperthermia at 42 °C for 60 min. After pretreatment, the cell viability, colony formation and DNA metabolism in HepG2 and the Na(+)-K(+)-ATPase activity, 2,3-diphosphoglycerate (2,3-DPG) concentration, free hemoglobin (Hb) level, osmotic fragility, membrane phosphatidylserine externalization, and blood gas variables in erythrocytes were determined. Pretreatment with cisplatin (50, 100, and 200 μg/ml) combined with hyperthermia (42 °C) for 60 min significantly decreased HepG2 cell viability, and completely inhibited colony formation and DNA metabolism when the HepG2 cell concentration was 5×10(4) ml(-1) in the erythrocyte (P2,3-DPG level, phosphatidylserine externalization, and extra-erythrocytic free Hb were significantly altered by hyperthermia plus high concentrations of cisplatin (100 and 200 μg/ml) (P0.05). In conclusion, pretreatment with cisplatin (50 μg/ml) combined with hyperthermia (42 °C) for 60 min effectively eliminated HepG2 cells from IBS but did not significantly affect erythrocytes in vitro.

Photoaffinity labeling of the human erythrocyte monosaccharide transporter with an aryl azide derivative of D-glucose

International Nuclear Information System (INIS)

Shanahan, M.F.; Wadzinski, B.E.; Lowndes, J.M.; Ruoho, A.E.

1985-01-01

A photoreactive, radioiodinated derivative of glucose, N-(4-iodoazidosalicyl)-6-amido-6-deoxyglucopyranose (IASA-glc), has been synthesized and used as a photoaffinity label for the human erythrocyte monosaccharide transporter. Photoinactivation and photoinsertion are both light-dependent and result in a marked decrease in the absorption spectra of the compound. When [ 125 I]IASA-glc was photolyzed with erythrocyte ghost membranes, photoinsertion of radiolabel was observed in three major regions, spectrin, band 3, and a protein of 58,000 daltons located in the zone 4.5 region. Of the three regions which were photolabeled, only labeling of polypeptides in the zone 4.5 region was partially blocked by D-glucose. In the non-iodinated form, N-(4-azidosalicyl)-6-amido-6-deoxy-glucopyranose inhibited the labeling of the transporter by [ 125 I]IASA-glc more effectively than D-glucose. The ability to synthesize this [ 125 I]containing photoprobe for the monosaccharide transporter at carrier-free levels offers several new advantages for investigating the structure of this transport protein in the erythrocyte

Conjugated Bilirubin Triggers Anemia by Inducing Erythrocyte Death

Science.gov (United States)

Lang, Elisabeth; Gatidis, Sergios; Freise, Noemi F; Bock, Hans; Kubitz, Ralf; Lauermann, Christian; Orth, Hans Martin; Klindt, Caroline; Schuier, Maximilian; Keitel, Verena; Reich, Maria; Liu, Guilai; Schmidt, Sebastian; Xu, Haifeng C; Qadri, Syed M; Herebian, Diran; Pandyra, Aleksandra A; Mayatepek, Ertan; Gulbins, Erich; Lang, Florian; Häussinger, Dieter; Lang, Karl S; Föller, Michael; Lang, Philipp A

2015-01-01

Hepatic failure is commonly associated with anemia, which may result from gastrointestinal bleeding, vitamin deficiency, or liver-damaging diseases, such as infection and alcohol intoxication. At least in theory, anemia during hepatic failure may result from accelerated clearance of circulating erythrocytes. Here we show that bile duct ligation (BDL) in mice leads to severe anemia despite increased reticulocyte numbers. Bilirubin stimulated suicidal death of human erythrocytes. Mechanistically, bilirubin triggered rapid Ca2+ influx, sphingomyelinase activation, formation of ceramide, and subsequent translocation of phosphatidylserine to the erythrocyte surface. Consistent with our in vitro and in vivo findings, incubation of erythrocytes in serum from patients with liver disease induced suicidal death of erythrocytes in relation to their plasma bilirubin concentration. Consistently, patients with hyperbilirubinemia had significantly lower erythrocyte and significantly higher reticulocyte counts compared to patients with low bilirubin levels. Conclusion: Bilirubin triggers suicidal erythrocyte death, thus contributing to anemia during liver disease. (Hepatology 2015;61:275–284) PMID:25065608

Spin Label Studies of the Hemoglobin-Membrane Interaction During Sickle Hemoglobin Polymerization

International Nuclear Information System (INIS)

Falcon Dieguez, Jose E.; Rodi, Pablo; Lores Guevara, Manuel A.; Gennaro, Ana Maria

2009-12-01

An enhanced hemoglobin-membrane association has been previously documented in Sickle Cell Anemia. However, it is not known how this interaction is modified during the hemoglobin S polymerization process. In this work, we use a model of reconstituted erythrocytes from ghost membranes whose cytoskeleton proteins had been previously labeled with the 4-maleimido Tempo spin label, and that were subsequently resealed with hemoglobin S or A solutions. Using EPR spectroscopy, we studied the time dependence of the spectral W/S parameter, indicative of the conformational state of cytoskeleton proteins (mainly spectrin) under spontaneous deoxygenation, with the aim of detecting the eventual effects due to hemoglobin S polymerization. The differences observed in the temporal behaviour of W/S in erythrocytes reconstituted with both hemoglobins were considered as experimental evidence of an increment in hemoglobin S-membrane interaction, as a result of the polymerization process of hemoglobin S under spontaneous deoxygenation. (author)

Sickle erythrocytes inhibit human endothelial cell DNA synthesis

International Nuclear Information System (INIS)

Weinstein, R.; Zhou, M.A.; Bartlett-Pandite, A.; Wenc, K.

1990-01-01

Patients with sickle cell anemia experience severe vascular occlusive phenomena including acute pain crisis and cerebral infarction. Obstruction occurs at both the microvascular and the arterial level, and the clinical presentation of vascular events is heterogeneous, suggesting a complex etiology. Interaction between sickle erythrocytes and the endothelium may contribute to vascular occlusion due to alteration of endothelial function. To investigate this hypothesis, human vascular endothelial cells were overlaid with sickle or normal erythrocytes and stimulated to synthesize DNA. The erythrocytes were sedimented onto replicate monolayers by centrifugation for 10 minutes at 17 g to insure contact with the endothelial cells. Incorporation of 3H-thymidine into endothelial cell DNA was markedly inhibited during contact with sickle erythrocytes. This inhibitory effect was enhanced more than twofold when autologous sickle plasma was present during endothelial cell labeling. Normal erythrocytes, with or without autologous plasma, had a modest effect on endothelial cell DNA synthesis. When sickle erythrocytes in autologous sickle plasma were applied to endothelial monolayers for 1 minute, 10 minutes, or 1 hour and then removed, subsequent DNA synthesis by the endothelial cells was inhibited by 30% to 40%. Although adherence of sickle erythrocytes to the endothelial monolayers was observed under these experimental conditions, the effect of sickle erythrocytes on endothelial DNA synthesis occurred in the absence of significant adherence. Hence, human endothelial cell DNA synthesis is partially inhibited by contact with sickle erythrocytes. The inhibitory effect of sickle erythrocytes occurs during a brief (1 minute) contact with the endothelial monolayers, and persists for at least 6 hours of 3H-thymidine labeling

Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome.

Science.gov (United States)

Lange, Philipp F; Huesgen, Pitter F; Nguyen, Karen; Overall, Christopher M

2014-04-04

A goal of the Chromosome-centric Human Proteome Project is to identify all human protein species. With 3844 proteins annotated as "missing", this is challenging. Moreover, proteolytic processing generates new protein species with characteristic neo-N termini that are frequently accompanied by altered half-lives, function, interactions, and location. Enucleated and largely void of internal membranes and organelles, erythrocytes are simple yet proteomically challenging cells due to the high hemoglobin content and wide dynamic range of protein concentrations that impedes protein identification. Using the N-terminomics procedure TAILS, we identified 1369 human erythrocyte natural and neo-N-termini and 1234 proteins. Multiple semitryptic N-terminal peptides exhibited improved mass spectrometric identification properties versus the intact tryptic peptide enabling identification of 281 novel erythrocyte proteins and six missing proteins identified for the first time in the human proteome. With an improved bioinformatics workflow, we developed a new classification system and the Terminus Cluster Score. Thereby we described a new stabilizing N-end rule for processed protein termini, which discriminates novel protein species from degradation remnants, and identified protein domain hot spots susceptible to cleavage. Strikingly, 68% of the N-termini were within genome-encoded protein sequences, revealing alternative translation initiation sites, pervasive endoproteolytic processing, and stabilization of protein fragments in vivo. The mass spectrometry proteomics data have been deposited to ProteomeXchange with the data set identifier .

Allosensibilisation to erythrocyte antigens (literature review

Directory of Open Access Journals (Sweden)

N. V. Mineeva

2015-01-01

Full Text Available In this article literature review of the causes of allosensibilisation to erythrocyte antigens are presented. It is shown that the ability to produce antierythrocyte antibodies is affected by many factors, principal of whom it is difficult to identify. For the allosensibilisation development requires genetically determined differences in erythrocyte antigens phenotypes of donor and recipient, mother and fetus, which can lead to immune response and antibodies production. The biochemical nature of erythrocyte antigens, antigen dose (the amount of transfused doses, the number of antigens determinants on donor and fetus erythrocytes, the number of pregnancies are important. Individual patient characteristics: age, gender, diseases, the use of immunosuppressive therapy and the presence of inflammatory processes, are also relevant. Note that antibody to one erythrocyte antigens have clinical value, and to the other – have no. The actual data about frequency of clinically significant antibodies contribute to the development of post-transfusion hemolytic complications prophylaxis as well as the improvement of laboratory diagnosis of hemolytic disease of the newborn in the presence of maternal antierythrocyte antibodies.

Vitamin-E reduces the oxidative damage on delta-aminolevulinic dehydratase induced by lead intoxication in rat erythrocytes.

Science.gov (United States)

Rendón-Ramirez, A; Cerbón-Solórzano, J; Maldonado-Vega, M; Quintanar-Escorza, M A; Calderón-Salinas, J V

2007-09-01

Lead intoxication induces oxidative damage on lipids and proteins. In the present paper we study in vivo and in vitro the antioxidant effect of vitamin-E and trolox, on the oxidative effects of lead intoxication in rat erythrocytes. Vitamin-E simultaneously administered to erythrocytes treated with lead was capable to prevent the inhibition of delta-aminolevulinic dehydratase activity and lipid oxidation. Partial but important protective effects were found when vitamin-E was administered either after or before lead exposure in rats. In vitro, the antioxidant trolox protected delta-ALA-D activity against damage induced by lead or menadione. These results indicate that vitamin-E could be useful in order to protect membrane-lipids and, notably, to prevent protein oxidation produced by lead intoxication.

An effective intracellular delivery system of monoclonal antibody for treatment of tumors: erythrocyte membrane-coated self-associated antibody nanoparticles

Science.gov (United States)

Gao, Lipeng; Han, Lin; Ding, Xiaoling; Xu, Jiaojiao; Wang, Jing; Zhu, Jianzhong; Lu, Weiyue; Sun, Jihong; Yu, Lei; Yan, Zhiqiang; Wang, Yiting

2017-08-01

Antibody-based drugs have attracted much attention for their targeting ability, high efficacy and low toxicity. But it is difficult for those intrabodies, a kind of antibody whose targets are intracellular biomarkers, to become effective drugs due to the lack of intracellular delivery strategy and their short circulation time in blood. Human telomerase reverse transcriptase (hTERT), an important biomarker for tumors, is expressed only in cytoplasm instead of on cell membrane. In this study, the anti-hTERT blocking monoclonal antibody (mAb), as the model intrabody, was used to prepare nanoparticles (NPs), followed by the encapsulation of erythrocyte membrane (EM), to obtain the EM-coated anti-hTERT mAb NPs delivery system. The final NPs showed a z-average hydrodynamic diameter of about 197.3 nm. The in vitro cellular uptake by HeLa cells confirmed that compared with free anti-hTERT mAb, the EM-coated anti-hTERT mAb NPs exhibited a significantly increased uptake by tumor cells. Besides, the pharmacokinetic study confirmed that the EM encapsulation can remarkably prolong the circulation time and increase the area under curve (AUC) of NPs in blood. The EM-coated anti-hTERT mAb NPs exhibited a remarkably decreased uptake by macrophages than uncoated NPs, which may be responsible for the prolonged circulation time and increased AUC. Furthermore, the frozen section of tumor tissue was performed and proved that the EM-coated anti-hTERT mAb NPs can be more effectively accumulated in tumor tissues than the free mAb and uncoated NPs. In summary, this study indicated that EM-coated anti-hTERT mAb NPs are an effective delivery system for the long circulation and intracellular delivery of an intrabody, and make it possible for the intracellular biomarkers to become the potential targets of drugs.

Metallic mercury uptake by catalase Part 1 In Vitro metallic mercury uptake by various kind of animals' erythrocytes and purified human erythrocyte catalase

OpenAIRE

劒持,堅志

1980-01-01

The uptake of metallic mercury was studied using erythrocytes with different catalase activities taken from various kind of animals. The results were: 1) The uptake of metallic mercury by erythrocytes paralleled the activity of catalase in the erythrocytes with and without hydrogen peroxide, suggesting that the erythrocyte catalase activity is related to the uptake of metallic mercury. 2) The uptake of metallic mercury occurred not only with purified human erythrocyte catalase but also with h...

Biophysics of malarial parasite exit from infected erythrocytes.

Science.gov (United States)

Chandramohanadas, Rajesh; Park, YongKeun; Lui, Lena; Li, Ang; Quinn, David; Liew, Kingsley; Diez-Silva, Monica; Sung, Yongjin; Dao, Ming; Lim, Chwee Teck; Preiser, Peter Rainer; Suresh, Subra

2011-01-01

Upon infection and development within human erythrocytes, P. falciparum induces alterations to the infected RBC morphology and bio-mechanical properties to eventually rupture the host cells through parasitic and host derived proteases of cysteine and serine families. We used previously reported broad-spectrum inhibitors (E64d, EGTA-AM and chymostatin) to inhibit these proteases and impede rupture to analyze mechanical signatures associated with parasite escape. Treatment of late-stage iRBCs with E64d and EGTA-AM prevented rupture, resulted in no major RBC cytoskeletal reconfiguration but altered schizont morphology followed by dramatic re-distribution of three-dimensional refractive index (3D-RI) within the iRBC. These phenotypes demonstrated several-fold increased iRBC membrane flickering. In contrast, chymostatin treatment showed no 3D-RI changes and caused elevated fluctuations solely within the parasitophorous vacuole. We show that E64d and EGTA-AM supported PV breakdown and the resulting elevated fluctuations followed non-Gaussian pattern that resulted from direct merozoite impingement against the iRBC membrane. Optical trapping experiments highlighted reduced deformability of the iRBC membranes upon rupture-arrest, more specifically in the treatments that facilitated PV breakdown. Taken together, our experiments provide novel mechanistic interpretations on the role of parasitophorous vacuole in maintaining the spherical schizont morphology, the impact of PV breakdown on iRBC membrane fluctuations leading to eventual parasite escape and the evolution of membrane stiffness properties of host cells in which merozoites were irreversibly trapped, recourse to protease inhibitors. These findings provide a comprehensive, previously unavailable, body of information on the combined effects of biochemical and biophysical factors on parasite egress from iRBCs.

[Erythrocyte blood groups and geographic pathology (author's transl)].

Science.gov (United States)

Salmon, C

1979-01-01

Blood groups are an obstacle to reproduction, transfusion and transplantation. There are immunological abortions due to the antibodies of "p" phenotype women; and Rh haemolytic disease of the new-born is in direct proportion to the frequency of the "r" gene in a given population; the problem of transfusional allo-immunisation is completely parallel. Certain membrane anomalies (due to exceptional erythrocyte blood groups--Rh null, Rh mod or McLeod, for example), can provoke hemolytic anaemias, but in these cases the subjects are scattered throughout the world. An important problem is that of the relationships between Duffy antigens and malaria: from what is known about plasmodium Knowlesi, Fya and Fyb antigens are related to the erythrocyte receptors for this plasmodium: the Fy(a-b-) red cells, even of exceptional non-blacks, are not infested with parasites. Two kinds of receptors are postulated: one for adherence and another for penetration. In contrast, plasmodium falciparum does not recognise the same receptors as plasmodium Knowlesi. Experiments carried out on man have led to the conclusion that plasmodium vivax also used Fya and Fyb antigens to penetrate the red cell. These recent facts give rise to the problem of a possible natural selection by plasmodium vivax, which would eradicate polymorphism, whilst until now, the facts concerning plasmodium falciparum have explained the balance of polymorphism.

Effects of Rambutan Peel Extract to The Number of Erythrocytes and Haemoglobin in Rats Exposed to Cigarette Smoke

Science.gov (United States)

Lisdiana; Dewi, F. K.

2017-04-01

Cigarette smoke is one of the exogenous free radicals sources. When it is inhaled, its activity may damage the structure of erythrocyte membrane function. The impacts of free radicals can be reduced through the provision of antioxidants. Rambutan fruit peel contains the phenolic compound in the form of polyphenols that are antioxidants. The purpose of this study is to determine the effect of rambutan fruit peel extracts to the number of erythrocytes and haemoglobin in rats exposed to cigarette smoke. This design used Post Test Control Group Design. A sample of 25 rats was divided into five groups, each group consisting of 5 rats. The positive control group (K+) were given a standard food and drinking water. The negative control group (K) by three cigarettes, the treatment group (KP1, KP2, KP3) by three cigarettes and skin extract of rambutan each treatment group with a dose 15 mg/kg, 30 mg/kg and 45 mg/kg for 30 days. Data on the number of erythrocytes and haemoglobin in rat blood was analysed with LSD and to determine the optimum dosage was analysed by using regression test. Research results shown that the content of rambutan fruit peel extract may increase the number of erythrocytes and haemoglobin of blood. Conclusions from this research are the rambutan fruit peel extract at a dose of 45 mg/kg body weight can increase and maintain the number of erythrocytes and haemoglobin in the blood of rat exposed to cigarette smoke.

P-gp expression levels in the erythrocytes of brown trout: a new tool for aquatic sentinel biomarker development.

Science.gov (United States)

Valton, Emeline; Wawrzyniak, Ivan; Amblard, Christian; Combourieu, Bruno; Bayle, Marie-Laure; Desmolles, François; Kwiatkowski, Fabrice; Penault-Llorca, Frédérique; Bamdad, Mahchid

2017-09-01

P-glycoprotein (P-gp) is a ubiquitous membrane detoxification pump involved in cellular defence against xenobiotics. Blood is a hub for the trade and transport of physiological molecules and xenobiotics. Our recent studies have highlighted the expression of a 140-kDa P-gp in brown trout erythrocytes in primary cell culture and its dose-dependent response to Benzo[a]pyrene pollutant. The purpose of this study was focused on using P-gp expression in brown trout erythrocytes as a biomarker for detecting the degree of river pollution. abcb1 gene and P-gp expression level were analysed by reverse transcriptase-PCR and Western blot, in the erythrocytes of brown trouts. The latter were collected in upstream and downstream of four rivers in which 17 polycyclic aromatic hydrocarbons and 348 varieties of pesticides micro-residues were analysed by liquid chromatography and mass spectrometry. The abcb1 gene and the 140-kDa P-gp were not expressed in trout erythrocytes from uncontaminated river. In contrast, they are clearly expressed in contaminated rivers, in correlation with the river pollution degree and the nature of the pollutants. This biological tool may offer considerable advantages since it provides an effective response to the increasing need for an early biomarker.

Invasion of erythrocytes by Babesia bovis

NARCIS (Netherlands)

Gaffar, Fasila Razzia

2004-01-01

In this thesis we investigated the invasion of erythrocytes taking place during the asexual erythrocytic blood stage of the apicomplexan parasites Babesia bovis parasite. Host cell invasion by apicomplexan parasites is a complex process requiring multiple receptor-ligand interactions, involving

Cell membrane as a possible site of Fröhlich's coherent oscillations

Science.gov (United States)

Blinowska, K. J.; Lech, W.; Wittlin, A.

1985-05-01

The microwave absorption spectra of erythrocytes and their ghosts have a resonant structure and reveal a close resemblance, indicating that the cell membrane is the primary site of Fröhlich's coherent oscillations.

HCIV-1 and Other Tailless Icosahedral Internal Membrane-Containing Viruses of the Family Sphaerolipoviridae

Directory of Open Access Journals (Sweden)

Tatiana A. Demina

2017-02-01

Full Text Available Members of the virus family Sphaerolipoviridae include both archaeal viruses and bacteriophages that possess a tailless icosahedral capsid with an internal membrane. The genera Alpha- and Betasphaerolipovirus comprise viruses that infect halophilic euryarchaea, whereas viruses of thermophilic Thermus bacteria belong to the genus Gammasphaerolipovirus. Both sequence-based and structural clustering of the major capsid proteins and ATPases of sphaerolipoviruses yield three distinct clades corresponding to these three genera. Conserved virion architectural principles observed in sphaerolipoviruses suggest that these viruses belong to the PRD1-adenovirus structural lineage. Here we focus on archaeal alphasphaerolipoviruses and their related putative proviruses. The highest sequence similarities among alphasphaerolipoviruses are observed in the core structural elements of their virions: the two major capsid proteins, the major membrane protein, and a putative packaging ATPase. A recently described tailless icosahedral haloarchaeal virus, Haloarcula californiae icosahedral virus 1 (HCIV-1, has a double-stranded DNA genome and an internal membrane lining the capsid. HCIV-1 shares significant similarities with the other tailless icosahedral internal membrane-containing haloarchaeal viruses of the family Sphaerolipoviridae. The proposal to include a new virus species, Haloarcula virus HCIV1, into the genus Alphasphaerolipovirus was submitted to the International Committee on Taxonomy of Viruses (ICTV in 2016.

Effects of an angelica extract on human erythrocyte aggregation, deformation and osmotic fragility.

Science.gov (United States)

Wang, X; Wei, L; Ouyang, J P; Muller, S; Gentils, M; Cauchois, G; Stoltz, J F

2001-01-01

In Chinese traditional medicine, angelica is widely used for its known clinical effects of ameliorating blood microcirculation. But the mechanism of these beneficial effects still remains unclear. In this work the rheological behaviour of human erythrocytes treated by angelica was studied in vitro. Normal RBCs incubated with an angelica extract at different concentrations (5, 10 or 20 mg/ml) for 60 min at 37 degrees C and then their aggregation, deformation and osmotic fragility were measured with different recently developed optical techniques, namely Erythroaggregometer (Regulest, Florange, France), LORCA (Mechatronics, Amsterdam) and Fragilimeter (Regulest, Florange, France). Experimental results show that angelica (20 mg/ml) significantly decreased normal RBCs' aggregation speed (p<0.01) and could inhibit the hyperaggregability caused by dextran 500. However, the strength of normal RBCs aggregates were not influenced by angelica. When a calcium ionophore A23187 (1.9 microM) was used to harden cell membrane, angelica (20 mg/ml) could significantly (p<0.01) protect erythrocytes against the loss of their deformability even it had no effects on normal RBCs deformation. Finally angelica (5 and 10 mg/ml) decreased significantly (p<0.01) normal RBCs osmotic fragility. In conclusion angelica plays a rheologically active role on human erythrocytes, and this study suggests a possible mechanism for angelica's positive effects against certain cardiovascular diseases.

The malaria parasite RhopH protein complex interacts with erythrocyte calmyrin identified from a comprehensive erythrocyte protein library.

Science.gov (United States)

Miura, Toyokazu; Takeo, Satoru; Ntege, Edward H; Otsuki, Hitoshi; Sawasaki, Tatsuya; Ishino, Tomoko; Takashima, Eizo; Tsuboi, Takafumi

2018-06-02

Malaria merozoite apical organelles; microneme and rhoptry secreted proteins play functional roles during and following invasion of host erythrocytes. Among numerous proteins, the rhoptries discharge high molecular weight proteins known as RhopH complex. Recent reports suggest that the RhopH complex is essential for growth and survival of the malaria parasite within erythrocytes. However, an in-depth understanding of the host-parasite molecular interactions is indispensable. Here we utilized a comprehensive mouse erythrocyte protein library consisting of 443 proteins produced by a wheat germ cell-free system, combined with AlphaScreen technology to identify mouse erythrocyte calmyrin as an interacting molecule of the rodent malaria parasite Plasmodium yoelii RhopH complex (PyRhopH). The PyRhopH interaction was dependent on the calmyrin N-terminus and divalent cation capacity. The finding unveils a recommendable and invaluable usefulness of our comprehensive mouse erythrocyte protein library together with the AlphaScreen technology in investigating a wide-range of host-parasite molecular interactions. Copyright © 2018 Elsevier Inc. All rights reserved.

Paired Chicken and Mammalian Erythrocyte Indicator Systems for ...

African Journals Online (AJOL)

Three levels of erythrocytes suspensions, 1.5%, 1% and 0.5% respectively from goat and guinea pig, were compared to conventional 0.5% chicken erythrocytes, in an attempt to investigate the suitability for the two sources of mammalian erythrocytes as indicators for Newcastle disease virus haemagglutination (HA) tests.

Unchanged Erythrocyte Profile After Exposure to Cryogenic Temperatures in Elder Marathon Runners

Directory of Open Access Journals (Sweden)

Jadwiga Szymura

2018-05-01

Full Text Available Objective: Endurance runners may experience “sports anemia” resulting from intravascular hemolysis. In addition, aging has negative impact on hematopoiesis and rheological properties of blood, and erythrocyte membranes in older people are more vulnerable to oxidative damage, which together can lead to anemia. Whole-body cryostimulation (WBCST is increasingly used in the elderly as a method of biological regeneration of athletes or therapy and preventive treatment. That is why the aim of the study was to determine whether repeated WBCST had an effect on the erythrocyte system in master marathon runners, compared to non-training men.Methods: Ten marathon runners (men aged 55.9 ± 5.5 years, training experience 6.71 ± 5.79 years and 10 non-training (men aged 62.0 ± 5.8 years were subjected to a series of 24 WBCST (3 min, -130°C performed every other day. Erythrocyte levels, interleukin-3 (IL-3, erythropoietin (EPO, haptoglobin, bilirubin, and extracellular hemoglobin (HGBecf concentrations were determined in the blood before and after 12, 24 WBCST, as well as 7 days after their completion.Results: The concentrations of EPO and IL-3 were significantly increased 7 days after the completion of WBCST in both groups (P < 0.05. The erythrocyte content and indicators, the bilirubin, haptoglobin, and HGBecf levels in each group did not change as a result of WBCST. In order to document hemolytic changes and/or factors affecting the severity of erythropoiesis, correlations between growth erythropoietic factors, erythrocyte and hemolytic factors as well as mutual correlations between hemolytic indexes were calculated. There was a positive correlation (P < 0.05 between the EPO and IL-3, bilirubin, mean corpuscular hemoglobin, and red blood cell distribution width – standard deviation. There was also a positive correlation between the concentrations of bilirubin and HGBecf, and a negative correlation between haptoglobin and HGBecf as well as bilirubin

Erythrocyte-derived nano-probes functionalized with antibodies for targeted near infrared fluorescence imaging of cancer cells

OpenAIRE

Anvari, Bahman; Mac, Jenny T.; Nunez, Vicente; Burns, Joshua M.; Guerrero, Yadir A.

2016-01-01

Constructs derived from mammalian cells are emerging as a new generation of nano-scale platforms for clinical imaging applications. Herein, we report successful engineering of hybrid nano-structures composed of erythrocyte-derived membranes doped with FDA-approved near infrared (NIR) chromophore, indocyanine green (ICG), and surface-functionalized with antibodies to achieve molecular targeting. We demonstrate that these constructs can be used for targeted imaging of cancer cells in vitro. The...

Plasmodium falciparum Adhesins Play an Essential Role in Signalling and Activation of Invasion into Human Erythrocytes.

Directory of Open Access Journals (Sweden)

Wai-Hong Tham

2015-12-01

Full Text Available The most severe form of malaria in humans is caused by the protozoan parasite Plasmodium falciparum. The invasive form of malaria parasites is termed a merozoite and it employs an array of parasite proteins that bind to the host cell to mediate invasion. In Plasmodium falciparum, the erythrocyte binding-like (EBL and reticulocyte binding-like (Rh protein families are responsible for binding to specific erythrocyte receptors for invasion and mediating signalling events that initiate active entry of the malaria parasite. Here we have addressed the role of the cytoplasmic tails of these proteins in activating merozoite invasion after receptor engagement. We show that the cytoplasmic domains of these type 1 membrane proteins are phosphorylated in vitro. Depletion of PfCK2, a kinase implicated to phosphorylate these cytoplasmic tails, blocks P. falciparum invasion of red blood cells. We identify the crucial residues within the PfRh4 cytoplasmic domain that are required for successful parasite invasion. Live cell imaging of merozoites from these transgenic mutants show they attach but do not penetrate erythrocytes implying the PfRh4 cytoplasmic tail conveys signals important for the successful completion of the invasion process.

Biochemical responses to cadmium exposure in Oncorhynchus mykiss erythrocytes.

Science.gov (United States)

Orlando, Patrick; Silvestri, Sonia; Ferlizza, Enea; Andreani, Giulia; Carpenè, Emilio; Falcioni, Giancarlo; Tiano, Luca; Isani, Gloria

2017-11-01

Cd is known for its carcinogenic effects, however its mechanism of toxicity and in particular its ability to promote oxidative stress is debated. In fact, although it is considered a redox-inactive metal, at high concentration Cd was shown to promote indirectly oxidative stress. In this study we investigated metal accumulation in ex vivo exposed trout (Oncorhynchus mykiss) erythrocytes and Cd dose-dependent effect in terms of RBC viability, cytosolic and mitochondrial ROS levels as well as its effects on mitochondrial membrane depolarization, hemoglobin stability and precipitation. In the concentration range used, Cd did not affect cell viability. However, metal accumulation was associated with an increase in all oxidative indexes evaluated, except mitochondrial superoxide anion production that, on the contrary, was significantly decreased, probably due to a lowered respiration rate associated with interference of Cd with complex I, II and III, as suggested by the observed Cd-dependent mitochondrial membrane depolarization. On the other hand, hemoglobin destabilisation seems to be the major trigger of oxidative stress in this cell type. Copyright © 2017. Published by Elsevier Inc.

Enzymatic assay for methotrexate in erythrocytes

DEFF Research Database (Denmark)

Schrøder, H; Heinsvig, E M

1985-01-01

Methotrexate (MTX) accumulates in erythrocytes in MTX-treated patients. We present a modified enzymatic assay measuring MTX concentrations between 10 and 60 nmol/l in erythrocytes, adapted for a centrifugal analyser (Cobas Bio). About 40 patient's samples could be analysed within 1 h. The detection...

a Study of the Electrical Impedance of Erythrocyte Membranes the Effects of Temperature and Radiation.

Science.gov (United States)

Gerig, Lee Harvey

The purpose of this work was to investigate the electrical impedance properties of Human Erythrocytes suspended in normal saline and specifically how radiation and temperature affected these properties. The cells were obtained by venepuncture from normal adult volunteers, washed three times and resuspended in phosphate buffered saline. The cells were irradiated by ('60)Co gamma rays to doses varying from 500 to 20,000 rads. The electrical impedance was measured using a computerized measurement and data acquisition system developed in the Biophysics Laboratory, School of Physics, University of New South Wales. The measurements were performed employing a four terminal technique and a digitally synthesized sine wave. The measurements revealed that nonirradiated blood from any specific individual had reproducible electrical properties from day to day and that there were only small differences in the electrical properties of blood from the various individuals sampled. This data displayed complex structure in both the capacitance versus frequency and conductance versus frequency curves. Of great interest was the dependence on the time post venesection, indicating a continual change in the state of the cells after removal from their natural environment. The experiments also revealed a non linear temperature dependence and a significant change in the suspension impedance as a function of absorbed dose. A model of the system was introduced which was able to emulate most of the measured phenomena. Studies of how the model can be adapted to fit the measured data for various cases (eg. time, temperature, radiation dose) suggested various physiological processes occurring within the membrane. The results were indicative of effects such as radiation induced changes in the lipid hydrocarbon region, the presence of a complex protein structure, the dissociation of charge within the protein, the presence of electrogenic pumps, and the destruction of the lipid matrix by radiation

Double-Skinned Forward Osmosis Membranes for Reducing Internal Concentration Polarization within the Porous Sublayer

KAUST Repository

Wang, Kai Yu

2010-05-19

A scheme to fabricate forward osmosis membranes comprising a highly porous sublayer sandwiched between two selective skin layers via phase inversion was proposed. One severe deficiency of existing composite and asymmetric membranes used in forward osmosis is the presence of unfavorable internal concentration polarization within the porous support layer that hinders both (i) separation (salt flux) and (ii) the performance (water flux). The double skin layers of the tailored membrane may mitigate the internal concentration polarization by preventing the salt and other solutes in the draw solution from penetrating into the membrane porous support. The prototype double-skinned cellulose acetate membrane displayed a water flux of 48.2 L·m-2·h -1 and lower reverse salt transport of 6.5 g·m -2·h-1 using 5.0 M MgCl2 as the draw solution in a forward osmosis process performed at 22 °C. This can be attributed to the effective salt rejection by the double skin layers and the low water transport resistance within the porous support layer. The prospects of utilizing the double-selective layer membranes may have potential application in forward osmosis for desalination. This study may help pave the way to improve the membrane design for the forward osmosis process. © 2010 American Chemical Society.

Double-Skinned Forward Osmosis Membranes for Reducing Internal Concentration Polarization within the Porous Sublayer

KAUST Repository

Wang, Kai Yu; Ong, Rui Chin; Chung, Tai-Shung

2010-01-01

A scheme to fabricate forward osmosis membranes comprising a highly porous sublayer sandwiched between two selective skin layers via phase inversion was proposed. One severe deficiency of existing composite and asymmetric membranes used in forward osmosis is the presence of unfavorable internal concentration polarization within the porous support layer that hinders both (i) separation (salt flux) and (ii) the performance (water flux). The double skin layers of the tailored membrane may mitigate the internal concentration polarization by preventing the salt and other solutes in the draw solution from penetrating into the membrane porous support. The prototype double-skinned cellulose acetate membrane displayed a water flux of 48.2 L·m-2·h -1 and lower reverse salt transport of 6.5 g·m -2·h-1 using 5.0 M MgCl2 as the draw solution in a forward osmosis process performed at 22 °C. This can be attributed to the effective salt rejection by the double skin layers and the low water transport resistance within the porous support layer. The prospects of utilizing the double-selective layer membranes may have potential application in forward osmosis for desalination. This study may help pave the way to improve the membrane design for the forward osmosis process. © 2010 American Chemical Society.

Internalization of components of the host cell plasma membrane during infection by Trypanosoma cruzi

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Carvalho TMU

1999-01-01

Full Text Available Epimastigote and trypomastigote forms of Trypanosoma cruzi attach to the macrophage surface and are internalized with the formation of a membrane bounded vacuole, known as the parasitophorous vacuole (PV. In order to determine if components of the host cell membrane are internalized during formation of the PV we labeled the macrophage surface with fluorescent probes for proteins, lipids and sialic acid residues and then allowed the labeled cells to interact with the parasites. The interaction process was interrupted after 1 hr at 37ºC and the distribution of the probes analyzed by confocal laser scanning microscopy. During attachment of the parasites to the macrophage surface an intense labeling of the attachment regions was observed. Subsequently labeling of the membrane lining the parasitophorous vacuole containing epimastigote and trypomastigote forms was seen. Labeling was not uniform, with regions of intense and light or no labeling. The results obtained show that host cell membrane lipids, proteins and sialoglycoconjugates contribute to the formation of the membrane lining the PV containing epimastigote and trypomastigote T. cruzi forms. Lysosomes of the host cell may participate in the process of PV membrane formation.

The Effects of Changing Membrane Compositions and Internal Electrolytes on the Respon of Potassium Ion Sensor

OpenAIRE

Ulianas, Alizar; Heng, Lee Yook

2015-01-01

A study on the changing of membrane compositions and internal solution towards the response potassium ion sensor was carried out. Potassium ion sensor based on photocured cross linking poly(n-butyl acrylate) membranes with varying composition of valinomycin (val), sodium tetrakis [3.5-bis(trifluoro-methyl) phenyl] borat (NaTFPB), types ion of internal solution were investigated. Effects of varying composition of val, NaTFPB, types and concentration of internal solution were observed on potass...

Internal humidifying of PEM [Proton Exchange Membrane] fuel cells

Energy Technology Data Exchange (ETDEWEB)

Staschewski, D [Karlsruhe Research Center (FZK), Karlsruhe (Germany). Inst. for Neutron Physics and Reactor Technics

1996-12-01

Hydrogen fuel cells (FC) for vehicular traction should stand out for a car-specific lightweight design. As regards PEMFC systems containing proton exchange membranes, this quality can be considerably improved by introducing porous bipolar plates which are conditioned by a water loop and deliver hot humidifying water to the adjacent membrane-electrode assembly (MEA). According to the principle of internal humidification here indicated special fuel cells based on sintered fiber and powder graphite were manufactured at FZK on a semi-technical scale. Self-made Pt/C electrodes hotpressed onto Nafion resulted in currents up to 200 A with pure oxygen as oxidant, providing the precondition for detailed studies of turnover and drainage rates within a monocell test arrangement. (author)

Plasma membrane cholesterol level and agonist-induced internalization of δ-opioid receptors; colocalization study with intracellular membrane markers of Rab family.

Science.gov (United States)

Brejchova, Jana; Vosahlikova, Miroslava; Roubalova, Lenka; Parenti, Marco; Mauri, Mario; Chernyavskiy, Oleksandr; Svoboda, Petr

2016-08-01

Decrease of cholesterol level in plasma membrane of living HEK293 cells transiently expressing FLAG-δ-OR by β-cyclodextrin (β-CDX) resulted in a slight internalization of δ-OR. Massive internalization of δ-OR induced by specific agonist DADLE was diminished in cholesterol-depleted cells. These results suggest that agonist-induced internalization of δ-OR, which has been traditionally attributed exclusively to clathrin-mediated pathway, proceeds at least partially via membrane domains. Identification of internalized pools of FLAG-δ-OR by colocalization studies with proteins of Rab family indicated the decreased presence of receptors in early endosomes (Rab5), late endosomes and lysosomes (Rab7) and fast recycling vesicles (Rab4). Slow type of recycling (Rab11) was unchanged by cholesterol depletion. As expected, agonist-induced internalization of oxytocin receptors was totally suppressed in β-CDX-treated cells. Determination of average fluorescence lifetime of TMA-DPH, the polar derivative of hydrophobic membrane probe diphenylhexatriene, in live cells by FLIM indicated a significant alteration of the overall PM structure which may be interpreted as an increased "water-accessible space" within PM area. Data obtained by studies of HEK293 cells transiently expressing FLAG-δ-OR by "antibody feeding" method were extended by analysis of the effect of cholesterol depletion on distribution of FLAG-δ-OR in sucrose density gradients prepared from HEK293 cells stably expressing FLAG-δ-OR. Major part of FLAG-δ-OR was co-localized with plasma membrane marker Na,K-ATPase and β-CDX treatment resulted in shift of PM fragments containing both FLAG-δ-OR and Na,K-ATPase to higher density. Thus, the decrease in content of the major lipid constituent of PM resulted in increased density of resulting PM fragments.

Calcium-dependent binding of Escherichia coli alpha-hemolysin to erythrocytes

International Nuclear Information System (INIS)

Boehm, D.F.

1989-01-01

Alpha hemolysin (AH), a protein secreted by certain strains of Escherichia coli, causes lysis of erythrocytes (RBCs) and is cytotoxic for other cells. The primary structure of AH contains an eight amino acid sequence tandemly repeated 13 times near the C-terminus. These repeated sequences are essential for hemolytic activity. AH also requires an unknown modification by an accessory protein, Hly C, for hemolytic activity. The role of calcium in the interaction of Ah with RBCs was investigated using recombinant strains which produced active and inactive forms of the toxin. Hemolytic activity was calcium-dependent. Osmotic protection experiments and immunoblots of SDS-PAGE separated proteins from washed, toxin-treated RBCs showed that the binding of active AH to RBCs was calcium-dependent. Binding of active AH to RBCs increased the calcium permeability of RBC membranes and resulted in changes in membrane protein profiles. The changes in membrane proteins did not cause the lysis of the cells. These results were consistent with a mechanism of lysis involving the formation of cation-selective pores in the membranes of target cells. 45 Ca-autoradiography of the recombinant hemolysins separated by SDS-PAGE and transferred to nitrocellulose showed that active AH bound calcium. The domain involved in binding calcium was identified as the tandemly repeated sequences since a deletion hemolysin missing 11 of the 13 repeated sequences did not bind calcium. This deletion hemolysin was non-hemolytic and did not bind to RBC membranes. Hemolysin lacking the Hly C modification was also non-hemolytic and did not bind to RBC membranes. This unmodified AH contained the repeated sequences and bound calcium as efficiently as active AH

Longxuetongluo Capsule Improves Erythrocyte Function against Lipid Peroxidation and Abnormal Hemorheological Parameters in High Fat Diet-Induced ApoE−/− Mice

Directory of Open Access Journals (Sweden)

Jiao Zheng

2016-01-01

Full Text Available Chinese dragon’s blood, the red resin of Dracaena cochinchinensis, one of the renowned traditional medicines, has been used to facilitate blood circulation and disperse blood stasis for thousands of years. Phenolic compounds are considered to be responsible for its main biological activities. In this study, total phenolic compounds of Chinese dragon’s blood were made into capsule (Longxuetongluo Capsule, LTC and their effects on the abnormal hemorheological properties were examined by high fat diet (HFD induced ApoE−/− mice. Compared to the model group, LTC recovered the abnormal hemorheological parameters in HFD-induced ApoE−/− mice by reducing whole blood viscosity (WBV at high rate and improving erythrocyte function. In conclusion, LTC could ameliorate erythrocyte deformability and osmotic fragility through the reduction of lipid peroxidation on plasma and erythrocyte membranes in HFD-induced ApoE−/− mice, which supported the traditional uses of Chinese dragon’s blood as an effective agent for improving blood microcirculation in hypercholesterolemia.

Erythrocyte Na+/K+ ATPase activity measured with sup 23 Na NMR

Energy Technology Data Exchange (ETDEWEB)

Ouwerkerk, R.; van Echteld, C.J.; Staal, G.E.; Rijksen, G. (University Hospital, Utrecht (Netherland))

1989-11-01

A {sup 23}Na NMR assay for measurement of erythrocyte Na+/K+ ATPase activity is presented. Using the nonpermeant shift reagent dysprosium tripolyphosphate the signals of intra- and extracellular sodium are separated, enabling measurement of sodium fluxes nondestructively, without the need to physically separate the cells from their environment. By increasing membrane permeability with nystatin we have shown that the assay allows the detection of differences in membrane permeability. With low doses of nystatin the ouabain-sensitive sodium flux increased more than twofold. With high doses of nystatin the Na+/K+ pump could not prevent an almost total equilibration of intra- and extracellular sodium. All sodium that entered the cells remained NMR visible, proving that sodium influx can be measured quantitatively. {sup 31}P NMR spectra taken before and after the assay revealed a slight acidification of the cells and no significant change in ATP concentration. No evidence of Dy3+ entering the cell was observed.

The effect of MLS laser radiation on cell lipid membrane.

Science.gov (United States)

Pasternak, Kamila; Wróbel, Dominika; Nowacka, Olga; Pieszyński, Ireneusz; Bryszewska, Maria; Kujawa, Jolanta

2018-03-14

Authors of numerous publications have proved the therapeutic effect of laser irradiation on biological material, but the mechanisms at cellular and subcellular level are not yet well understood. The aim of this study was to assess the effect of laser radiation emitted by the MLS M1 system (Multiwave Locked System) at two wavelengths (808 nm continuous and 905 nm pulsed) on the stability and fluidity of liposomes with a lipid composition similar to that of human erythrocyte membrane or made of phosphatidylocholine. Liposomes were exposed to low-energy laser radiation at surface densities 195 mW/cm2 (frequency 1,000 Hz) and 230 mW/cm2 (frequency 2,000 Hz). Different doses of radiation energy in the range 0-15 J were applied. The surface energy density was within the range 0.46 - 4.9 J/cm 2. The fluidity and stability of liposomes subjected to such irradiation changed depending on the parameters of radiation used. Since MLS M1 laser radiation, depending on the parameters used, affects fluidity and stability of liposomes with the lipid content similar to erythrocyte membrane, it may also cause structural and functional changes in cell membranes.

Local anesthetics: interaction with human erythrocyte membranes as studied by {sup 1}H and {sup 31}P nuclear magnetic resonance; Anestesicos locais: interacao com membranas de eritrocitos de sangue humano, estudada por ressonancia magnetica nuclear de {sup 1}H e {sup 31}P

Energy Technology Data Exchange (ETDEWEB)

Fraceto, Leonardo Fernandes; Paula, Eneida de [Universidade Estadual de Campinas, SP (Brazil). Inst. de Biologia. Dept. de Bioquimica]. E-mail: depaula@unicamp.br

2004-02-01

The literature carries many theories about the mechanism of action of local anesthetics (LA). We can highlight those focusing the direct effect of LA on the sodium channel protein and the ones that consider the interaction of anesthetic molecules with the lipid membrane phase. The interaction between local anesthetics and human erythrocyte membranes has been studied by {sup 1}H and {sup 31}P nuclear magnetic resonance spectroscopy. It was found that lidocaine (LDC) and benzocaine (BZC) bind to the membranes, increase the mobility of the protons of the phospholipids acyl chains, and decrease the mobility and/or change the structure of the polar head groups. The results indicate that lidocaine molecules are inserted across the polar and liquid interface of the membrane, establishing both electrostatic (charged form) and hydrophobic (neutral form) interactions. Benzocaine locates itself a little deeper in the bilayer, between the interfacial glycerol region and the hydrophobic core. These changes in mobility or conformation of membrane lipids could affect the Na{sup +}-channel protein insertion in the bilayer, stabilizing it in the inactivated state, thus causing anesthesia. (author)

Synthetic nanoparticles camouflaged with biomimetic erythrocyte membranes for reduced reticuloendothelial system uptake

International Nuclear Information System (INIS)

Rao, Lang; Xu, Jun-Hua; Cai, Bo; Liu, Huiqin; Li, Ming; Jia, Yan; Xiao, Liang; Guo, Shi-Shang; Liu, Wei; Zhao, Xing-Zhong

2016-01-01

Suppression of the reticuloendothelial system (RES) uptake is one of the most challenging tasks in nanomedicine. Coating stratagems using polymers, such as poly(ethylene glycol) (PEG), have led to great success in this respect. Nevertheless, recent observations of immunological response toward these synthetic polymers have triggered a search for better alternatives. In this work, natural red blood cell (RBC) membranes are camouflaged on the surface of Fe 3 O 4 nanoparticles for reducing the RES uptake. In vitro macrophage uptake, in vivo biodistribution and pharmacokinetic studies demonstrate that the RBC membrane is a superior alternative to the current gold standard PEG for nanoparticle ‘stealth’. Furthermore, we systematically investigate the in vivo potential toxicity of RBC membrane-coated nanoparticles by blood biochemistry, whole blood panel examination and histology analysis based on animal models. The combination of synthetic nanoparticles and natural cell membranes embodies a novel and biomimetic nanomaterial design strategy and presents a compelling property of functional materials for a broad range of biomedical applications. (paper)

Hydroxychloroquine binding to cytoplasmic domain of Band 3 in human erythrocytes: Novel mechanistic insights into drug structure, efficacy and toxicity.

Science.gov (United States)

Nakagawa, Mizuki; Sugawara, Kotomi; Goto, Tatsufumi; Wakui, Hideki; Nunomura, Wataru

2016-05-13

Hydroxychloroquine (HCQ) is a widely used drug in the treatment of autoimmune diseases, such as arthritis and systemic lupus erythematosus. It has also been prescribed for the treatment of malaria owing to its lower toxicity compared to its closely related compound chloroquine (CQ). However, the mechanisms of action of HCQ in erythrocytes (which bind preferentially this drug) have not been documented and the reasons underlying the lower side effects of HCQ compared to CQ remain unclear. Here we show that, although the activity of erythrocyte lactate dehydrogenase (LDH), but not GAPDH, was inhibited by both HCQ and CQ in vitro, LDH activity in erythrocytes incubated with 20 mM HCQ was not significantly reduced within 5 h in contrast to CQ did. Using HCQ coupled Sepharose chromatography (HCQ-Sepharose), we identified Band 3, spectrin, ankyrin, protein 4.1R and protein 4.2 as HCQ binding proteins in human erythrocyte plasma membrane. Recombinant cytoplasmic N-terminal 43 kDa domain of Band 3 bound to HCQ-Sepharose and was eluted with 40 mM (but not 20 mM) HCQ. Band 3 transport activity was reduced by only 23% in the presence of 20 mM HCQ. Taken together, these data demonstrate that HCQ binds to the cytoplasmic N-terminal domain of Band 3 in human erythrocytes but does not inhibit dramatically its transport activity. We hypothesize that the trapping of HCQ on Band 3 contributes to the lower side effects of the drug on energy production in erythrocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

Erythrocyte membrane-encapsulated celecoxib improves the cognitive decline of Alzheimer's disease by concurrently inducing neurogenesis and reducing apoptosis in APP/PS1 transgenic mice.

Science.gov (United States)

Guo, Jing-Wen; Guan, Pei-Pei; Ding, Wei-Yan; Wang, Si-Ling; Huang, Xue-Shi; Wang, Zhan-You; Wang, Pu

2017-11-01

Alzheimer's disease (AD) is characterized by the loss of neurogenesis and excessive induction of apoptosis. The induction of neurogenesis and inhibition of apoptosis may be a promising therapeutic approach to combating the disease. Celecoxib (CB), a cyclooxygenase-2 specific inhibitor, could offer neuroprotection. Specifically, the CB-encapsulated erythrocyte membranes (CB-RBCMs) sustained the release of CB over a period of 72 h in vitro and exhibited high brain biodistribution efficiency following intranasal administration, which resulted in the clearance of aggregated β-amyloid proteins (Aβ) in neurons. The high accumulation of the CB-RBCMs in neurons resulted in a decrease in the neurotoxicity of CB and an increase in the migratory activity of neurons, and alleviated cognitive decline in APP/PS1 transgenic (Tg) mice. Indeed, COX-2 metabolic products including prostaglandin E2 (PGE 2 ) and PGD 2 , PGE 2 induced neurogenesis by enhancing the expression of SOD2 and 14-3-3ζ, and PGD 2 stimulated apoptosis by increasing the expression of BIK and decreasing the expression of ARRB1. To this end, the CB-RBCMs achieved better effects on concurrently increasing neurogenesis and decreasing apoptosis than the phospholipid membrane-encapsulated CB liposomes (CB-PSPD-LPs), which are critical for the development and progression of AD. Therefore, CB-RBCMs provide a rational design to treat AD by promoting the self-repairing capacity of the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Erythrocyte and platelet fatty acids in retinitis pigmentosa.

Science.gov (United States)

Stanzial, A M; Bonomi, L; Cobbe, C; Olivieri, O; Girelli, D; Trevisan, M T; Bassi, A; Ferrari, S; Corrocher, R

1991-05-01

The fatty acid composition and the glutathione-peroxidase activity (GSH-Px) of erythrocytes and platelets, the production of malondialdehyde (MDA) by platelets and the activity of the main systems of transmembrane cation transport in erythrocyte have been studied in 12 patients (5 males and 7 females) affected by retinitis pigmentosa (RP). A remarkable increase of saturated fatty acids (SFA), particularly of stearic acid (C18:0), has been noted in these patients. The reduced unsaturated/saturated fatty acids ratio (PUFA/SFA) observed in both erythrocytes and platelets and the decrease of arachidonic acid in platelets may depend by an active peroxidation process as documented by the increase of MDA. Platelet glutathione-peroxidase (PTL-GSH-PX) and plasma retinol were in the normal range, whereas erythrocyte glutathione-peroxidase (E-GSH-PX), MDA and plasma alfa-toco-pherol were increased in patients with RP. The activities of Na(+)-K+ pump, cotransport and Na(+)-Li+ countertransport were normal in RP erythrocytes.

Hepatic or splenic targeting of carrier erythrocytes: a murine model

International Nuclear Information System (INIS)

Zocchi, E.; Guida, L.; Benatti, U.; Canepa, M.; Borgiani, L.; Zanin, T.; De Flora, A.

1987-01-01

Carrier mouse erythrocytes, i.e., red cells, subjected to a dialysis technique involving transient hypotonic hemolysis and isotonic resealing were treated in vitro in three different ways: (a) energy depletion by exposure for 90 min at 42 degrees C; (b) desialylation by incubation with neuroaminidase; and (c) oxidative stress by incubation with H 2 O 2 and NaN3. Procedure (c) afforded maximal damage, as shown by analysis of biochemical properties of the treated erythrocytes. Reinfusion in mice of the variously manipulated erythrocytes following their 51 Cr labeling showed extensive fragilization as indicated by rapid clearance of radioactivity from the circulation. Moreover, both the energy-depleted and the neuraminidase-treated erythrocytes showed a preferential liver uptake, reaching 50 and 75%, respectively, within 2 h. On the other hand, exposure of erythrocytes to the oxidant stress triggered a largely splenic removal, accounting for almost 40% of the reinjected cells within 4 h. Transmission electron microscopy of liver from mice receiving energy-depleted erythrocytes demonstrated remarkable erythrocyte congestion within the sinusoids, followed by hyperactivity of Kupffer cells and by subsequent thickening of the perisinusoidal Disse space. Concomitantly, levels of serum transaminase activities were moderately increased. Each of the three procedures of manipulation of carrier erythrocytes may prove applicable under conditions where selective targeting of erythrocyte-encapsulated chemicals and drugs to either the liver or the spleen has to be achieved

Human erythrocytes inhibit complement-mediated solubilization of immune complexes by human serum

International Nuclear Information System (INIS)

Dorval, B.L.

1987-01-01

The aim of this study was to develop an autologus human system to evaluate the effects of human erythrocytes on solubilization of immune complex precipitates (IC) by human serum. Incubation of IC with fresh human serum or guinea pig serum resulted in solubilization of IC. When packed erythrocytes were added to human serum or guinea pig serum binding of IC to the erythrocyte occurred and IC solubilization was inhibited significantly (p <.025). Sheep erythrocytes did not bind IC or inhibit IC solubilization. To evaluate the role of human erythrocyte complement receptor (CR1) on these findings, human erythrocytes were treated with trypsin or anti-CR1 antibodies. Both treatments abrogated IC binding to human erythrocytes but did not affect the ability of the human erythrocyte to inhibit IC solubilization. Radioimmunoassay was used to measure C3, C4 and C5 activation in human serum after incubation with IC, human erythrocytes, human erythrocytes plus IC, whole blood or in whole blood plus IC

Kinetics of viral load and erythrocytic inclusion body formation in pacific herring artificially infected with erythrocytic necrosis virus

Science.gov (United States)

Glenn, Jolene A.; Emmenegger, Eveline J.; Grady, Courtney A.; Roon, Sean R.; Gregg, Jacob L.; Conway, Carla M.; Winton, James R.; Hershberger, Paul K.

2012-01-01

Viral erythrocytic necrosis (VEN) is a condition that affects marine and anadromous fish species, including herrings and salmonids, in the Atlantic and Pacific oceans. Infection is frequently associated with severe anemia and causes episodic mortality among wild and hatchery fish when accompanied by additional stressors; VEN can be presumptively diagnosed by (1) light microscopic identification of a single characteristic—a round, magenta-colored, 0.8-μm-diameter inclusion body (IB) within the cytoplasm of erythrocytes and their precursors on Giemsa-stained blood films; or (2) observation (via transmission electron microscopy [TEM]) of the causative iridovirus, erythrocytic necrosis virus (ENV), within erythrocytes or their precursors. To better understand the kinetics of VEN, specific-pathogen-free Pacific herring Clupea pallasii were infected with ENV by intraperitoneal injection. At 1, 4, 7, 10, 14, 21, and 28 d postexposure, samples of blood, spleen, and kidney were collected and assessed (1) via light microscopy for the number of intracytoplasmic IBs in blood smears and (2) via TEM for the number of virions within erythrocytes. The mean prevalence of intracytoplasmic IBs in the blood cells increased from 0% at 0–4 d postexposure to 94% at 28 d postexposure. Viral load within circulating red blood cells peaked at 7 d postexposure, fell slightly, and then reached a plateau. However, blood cells observed within the kidney and spleen tissues demonstrated high levels of ENV between 14 and 28 d postexposure. The results indicate that the viral load within erythrocytes does not correlate well with IB prevalence and that the virus can persist in infected fish for more than 28 d.

Factors influencing erythrocyte choline concentrations.

Science.gov (United States)

Miller, B L; Jenden, D J; Tang, C; Read, S

1989-01-01

Choline concentrations in human erythrocytes increase after freezing and thawing, during incubation in Krebs-phosphate for 30 min or on storage at 0 degrees C for 3-24 hr. The increase is prevented by protein precipitation by 10% perchloric acid, 10% zinc hydroxide, 10% sodium tungstate or boiling in water. It is not prevented by EDTA (10 mM) and is increased by oleate (5 mM). We suggest that the increase is due to the action of phospholipase D on erythrocyte phospholipids.

Bioassessment of the Effluents Discharged from Two Export Oriented Industrial Zones Located in Kelani River Basin, Sri Lanka Using Erythrocytic Responses of the Fish, Nile Tilapia (Oreochromis niloticus).

Science.gov (United States)

Hemachandra, C K; Pathiratne, A

2017-10-01

Complex effluents originating from diverse industrial processes in industrial zones could pose cytotoxic/genotoxic hazards to biota in the receiving ecosystems which cannot be revealed by conventional monitoring methods. This study assessed potential cytotoxicity/genotoxicity of treated effluents of two industrial zones which are discharged into Kelani river, Sri Lanka combining erythrocytic abnormality tests and comet assay of the tropical model fish, Nile tilapia. Exposure of fish to the effluents induced erythrocytic DNA damage and deformed erythrocytes with serrated membranes, vacuolations, nuclear buds and micronuclei showing cytotoxic/genotoxic hazards in all cases. Occasional exceedance of industrial effluent discharge regulatory limits was noted for color and lead which may have contributed to the observed cytotoxicity/genotoxicity of effluents. The results demonstrate that fish erythrocytic responses could be used as effective bioanalytical tools for cytotoxic/genotoxic hazard assessments of complex effluents of industrial zones for optimization of the waste treatment process in order to reduce biological impacts.

Erythrocytes labelling for to value bleeding of digestive tract in pediatrics

International Nuclear Information System (INIS)

Mora, R.

2002-01-01

The erythrocytes labelling has been facilitated by several factors: a) They are the cellular elements more abundant in the blood (5 x 10 9 / ml blood). b) They are easy to be isolated and manipulated In vitro and they are not very sensitive to the physical or chemical damages. c) They do not depend on energy or nutritious requirements as another cellular elements In vitro. d) With respect to another cells they show an easier labelling with radionuclides due to the availability of a variety of transporter mechanisms and of internal hemoglobin which is rich in active metal with multiple union sites. The erythrocytes are biconcave disks without nucleus composed by a 65% water, 32% hemoglobin and a 3% by lipids and proteins which form the stroma.The hemoglobin is the most important component of erythrocytes, it contains 4 heme groups and one globin molecule (with molecular weight of 68000) and fix iron covalently with 4 atoms of nitrogenated porfyrin. The oxygen is reversibly joined to iron. The hemoglobin does not experiment re-synthesis or degradation during its lifetime in the erythrocyte. It has been stipulated that the diagnostic applications in nuclear medicine are: a) That the radionuclide should have a high intensity of emission with an adequate energy for the image, with minimum particulate radiation and a half life time average similar to the length of the study that is carried out. b) That the radionuclide is joined firmly to the In vivo cells without altering physical and biochemical properties of the cells and their function In vitro. c) That the radionuclide once incorporated to the interior of cell must not be liberated during the study neither reused after of destruction. A quick procedure is now found available for labelling erythrocytes with 99m Tc offering a high performance and quality labelling. This is narrowly related to the 99m Tc chemistry understanding. (Author)

Induction of transient radioresistance in human erythrocytes

International Nuclear Information System (INIS)

Krokosz, Anita; Szweda-Lewandowska, Zofia

2006-01-01

Human erythrocytes suspended in an isotonic Na-phosphate buffer, pH 7.4 (hematocrit of 2%), were irradiated with γ-rays with single and split doses under air or N 2 O in order to determine the physicochemical changes caused by the dose inducing an increase in resistance to radiation-induced hemolysis. The obtained results showed that under the applied irradiation conditions, the dose of 0.4 kGy induced changes in erythrocytes, which were responsible for temporary resistance of erythrocytes to hemolysis. We concluded that the observed resistance is caused mainly by the structural changes in proteins

Diminution of Oxidative Damage to Human Erythrocytes and Lymphocytes by Creatine: Possible Role of Creatine in Blood.

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Neha Qasim

Full Text Available Creatine (Cr is naturally produced in the body and stored in muscles where it is involved in energy generation. It is widely used, especially by athletes, as a staple supplement for improving physical performance. Recent reports have shown that Cr displays antioxidant activity which could explain its beneficial cellular effects. We have evaluated the ability of Cr to protect human erythrocytes and lymphocytes against oxidative damage. Erythrocytes were challenged with model oxidants, 2, 2'-azobis(2-amidinopropane dihydrochloride (AAPH and hydrogen peroxide (H2O2 in the presence and absence of Cr. Incubation of erythrocytes with oxidant alone increased hemolysis, methemoglobin levels, lipid peroxidation and protein carbonyl content. This was accompanied by decrease in glutathione levels. Antioxidant enzymes and antioxidant power of the cell were compromised while the activity of membrane bound enzyme was lowered. This suggests induction of oxidative stress in erythrocytes by AAPH and H2O2. However, Cr protected the erythrocytes by ameliorating the AAPH and H2O2 induced changes in these parameters. This protective effect was confirmed by electron microscopic analysis which showed that oxidant-induced cell damage was attenuated by Cr. No cellular alterations were induced by Cr alone even at 20 mM, the highest concentration used. Creatinine, a by-product of Cr metabolism, was also shown to exert protective effects, although it was slightly less effective than Cr. Human lymphocytes were similarly treated with H2O2 in absence and presence of different concentrations of Cr. Lymphocytes incubated with oxidant alone had alterations in various biochemical and antioxidant parameters including decrease in cell viability and induction of DNA damage. The presence of Cr attenuated all these H2O2-induced changes in lymphocytes. Thus, Cr can function as a blood antioxidant, protecting cells from oxidative damage, genotoxicity and can potentially increase their

α2-macroglobulin can crosslink multiple Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) molecules and may facilitate adhesion of parasitized erythrocytes

DEFF Research Database (Denmark)

Stevenson, Liz; Laursen, Erik; Cowan, Graeme J

2015-01-01

-macroglobulin (α2M), which is both required and sufficient for rosetting mediated by the PfEMP1 protein HB3VAR06 and some other rosette-mediating PfEMP1 proteins. We map the α2M binding site to the C terminal end of HB3VAR06, and demonstrate that α2M can bind at least four HB3VAR06 proteins, plausibly....... Together, our results are evidence that P. falciparum parasites exploit α2M (and IgM) to expand the repertoire of host receptors available for PfEMP1-mediated IE adhesion, such as the erythrocyte carbohydrate moieties that lead to formation of rosettes. It is likely that this mechanism also affects IE...

Comparison of the oxime-induced reactivation of rhesus monkey, swine and guinea pig erythrocyte acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity.

Science.gov (United States)

Herkert, Nadja M; Lallement, Guy; Clarençon, Didier; Thiermann, Horst; Worek, Franz

2009-04-28

Recently, a dynamically working in vitro model with real-time determination of membrane-bound human acetylcholinesterase (AChE) activity was shown to be a versatile model to investigate oxime-induced reactivation kinetics of organophosphate- (OP) inhibited enzyme. In this assay, AChE was immobilized on particle filters which were perfused with acetylthiocholine, Ellman's reagent and phosphate buffer. Subsequently, AChE activity was continuously analyzed in a flow-through detector. Now, it was an intriguing question whether this model could be used with erythrocyte AChE from other species in order to investigate kinetic interactions in the absence of annoying side reactions. Rhesus monkey, swine and guinea pig erythrocytes were a stable and highly reproducible enzyme source. Then, the model was applied to the reactivation of sarin- and paraoxon-inhibited AChE by obidoxime or HI 6 and it could be shown that the derived reactivation rate constants were in good agreement to previous results obtained from experiments with a static model. Hence, this dynamic model offers the possibility to investigate highly reproducible interactions between AChE, OP and oximes with human and animal AChE.

Erythrocyte metallothionein as an index of zinc status in humans

International Nuclear Information System (INIS)

Grider, A.; Bailey, L.B.; Cousins, R.J.

1990-01-01

Metallothionein concentrations in erythrocyte lysates derived from human subjects were measured by an ELISA procedure. IgG obtained from serum of sheep injected with human metallothionein 1 was used in this competitive assay. Subjects were fed a semipurified zinc-deficient diet for an 8-day depletion period after 3 days of acclimation. Fasting plasma zinc concentrations were reduced ∼7%. Metallothionein in the erythrocyte lysates was significantly decreased to 59% of the initial level by the end of the depletion period. Supplementation of these depleted subjects with zinc did not increase erythrocyte metallothionein levels within 24 hr. Daily supplementation of control subjects with zinc increased erythrocyte metallothionein to a 7-fold maximum within 7 days. These levels were reduced by 61% within 14 days after zinc supplementation was terminated. Incubation of rat [ 35 S]metallothionein with human erythrocyte lysate showed a time-dependent increase in 35 S soluble in 20% trichloroacetic acid, indicating degradation of the labeled protein, presumably via protease activity in the lysate. It is proposed that zinc supplementation induces erythrocyte metallothionein during erythropoiesis and that low zinc intake decreases synthesis and/or accelerates degradation of the protein in reticulocytes/erythrocytes. Metallothionein levels in erythrocytes may provide a useful index upon which to assess zinc status in humans

Cell activation and cellular-cellular interactions during hemodialysis: effect of dialyzer membrane.

Science.gov (United States)

Sirolli, V; Ballone, E; Di Stante, S; Amoroso, L; Bonomini, M

2002-06-01

During hemodialysis (HD), circulating blood cells can be activated and also engage in dynamic interplay. These phenomena may be important factors behind dialysis membrane bio(in)compatibility. In the present prospective cross-over study, we have used flow cytometry to evaluate the influence of different dialysis membranes on the activation of circulating blood cells (leukocytes, platelets) and their dynamic interactions (formation of circulating platelet-leukocyte and platelet-erythrocyte aggregates) during in vivo HD. Each patient (n = 10) was treated with dialyzers containing membranes of cellulose diacetate, polysulfone and ethylenevinylalcohol (EVAL) in a randomized order. Upregulation of adhesion receptor expression (CD15s, CD11b/CD18) occurred mainly with the cellulosic membrane, though an increase in CD11b/CD18 circulating on neutrophils was also found with both synthetic membranes. Circulating activated platelets (P-selectin/CD63-positive platelets) increased during HD sessions with cellulose diacetate and polysulfone. An increased formation of platelet-neutrophil aggregates was found at 15 and 30 min during dialysis with cellulose diacetate and polysulfone but not with EVAL. Platelet-erythrocyte aggregates also increased with cellulose diacetate and at 15 min with polysulfone as well. Generally in concomitance with the increase in platelet-neutrophil coaggregates, there was an increased hydrogen peroxide production by neutrophils. The results of this study indicate that cellular mechanisms can be activated during HD largely depending on the membrane material, EVAL causing less reactivity than the other two membranes. It appears that each dialysis membrane has multiple and different characteristics that may contribute to interactions with blood components. Our results also indicate that derivatizing cellulose (cellulose diacetate) may be a useful way to improve the biocompatibility of the cellulose polymer and that there may be great variability in the

ABO Blood Groups Influence Macrophage-mediated Phagocytosis of Plasmodium falciparum-infected Erythrocytes

Science.gov (United States)

Branch, Donald R.; Hult, Annika K.; Olsson, Martin L.; Liles, W. Conrad; Cserti-Gazdewich, Christine M.; Kain, Kevin C.

2012-01-01

Erythrocyte polymorphisms associated with a survival advantage to Plasmodium falciparum infection have undergone positive selection. There is a predominance of blood group O in malaria-endemic regions, and several lines of evidence suggest that ABO blood groups may influence the outcome of P. falciparum infection. Based on the hypothesis that enhanced innate clearance of infected polymorphic erythrocytes is associated with protection from severe malaria, we investigated whether P. falciparum-infected O erythrocytes are more efficiently cleared by macrophages than infected A and B erythrocytes. We show that human macrophages in vitro and mouse monocytes in vivo phagocytose P. falciparum-infected O erythrocytes more avidly than infected A and B erythrocytes and that uptake is associated with increased hemichrome deposition and high molecular weight band 3 aggregates in infected O erythrocytes. Using infected A1, A2, and O erythrocytes, we demonstrate an inverse association of phagocytic capacity with the amount of A antigen on the surface of infected erythrocytes. Finally, we report that enzymatic conversion of B erythrocytes to type as O before infection significantly enhances their uptake by macrophages to observed level comparable to that with infected O wild-type erythrocytes. These data provide the first evidence that ABO blood group antigens influence macrophage clearance of P. falciparum-infected erythrocytes and suggest an additional mechanism by which blood group O may confer resistance to severe malaria. PMID:23071435

Isolation and Characterization of Glycophorin from Carp Red Blood Cell Membranes

Directory of Open Access Journals (Sweden)

Takahiko Aoki

2014-08-01

Full Text Available We isolated a high-purity carp glycophorin from carp erythrocyte membranes following extraction using the lithium diiodosalicylate (LIS-phenol method and streptomycin treatment. The main carp glycophorin was observed to locate at the position of the carp and human band-3 proteins on an SDS-polyacrylamide gel. Only the N-glycolylneuraminic acid (NeuGc form of sialic acid was detected in the carp glycophorin. The oligosaccharide fraction was separated into two components (P-1 and P-2 using a Glyco-Pak DEAE column. We observed bacteriostatic activity against five strains of bacteria, including two known fish pathogens. Fractions from the carp erythrocyte membrane, the glycophorin oligosaccharide and the P-1 also exhibited bacteriostatic activity; whereas the glycolipid fraction and the glycophorin fraction without sialic acid did not show the activity. The carp glycophorin molecules attach to the flagellum of V. anguillarum or the cell surface of M. luteus and inhibited bacterial growth.

Increase in average foveal thickness after internal limiting membrane peeling

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Kumagai K

2017-04-01

Full Text Available Kazuyuki Kumagai,1 Mariko Furukawa,1 Tetsuyuki Suetsugu,1 Nobuchika Ogino2 1Department of Ophthalmology, Kami-iida Daiichi General Hospital, 2Department of Ophthalmology, Nishigaki Eye Clinic, Aichi, Japan Purpose: To report the findings in three cases in which the average foveal thickness was increased after a thin epiretinal membrane (ERM was removed by vitrectomy with internal limiting membrane (ILM peeling.Methods: The foveal contour was normal preoperatively in all eyes. All cases underwent successful phacovitrectomy with ILM peeling for a thin ERM. The optical coherence tomography (OCT images were examined before and after the surgery. The changes in the average foveal (1 mm thickness and the foveal areas within 500 µm from the foveal center were measured. The postoperative changes in the inner and outer retinal areas determined from the cross-sectional OCT images were analyzed.Results: The average foveal thickness and the inner and outer foveal areas increased significantly after the surgery in each of the three cases. The percentage increase in the average foveal thickness relative to the baseline thickness was 26% in Case 1, 29% in Case 2, and 31% in Case 3. The percentage increase in the foveal inner retinal area was 71% in Case 1, 113% in Case 2, and 110% in Case 3, and the percentage increase in foveal outer retinal area was 8% in Case 1, 13% in Case 2, and 18% in Case 3.Conclusion: The increase in the average foveal thickness and the inner and outer foveal areas suggests that a centripetal movement of the inner and outer retinal layers toward the foveal center probably occurred due to the ILM peeling. Keywords: internal limiting membrane, optical coherence tomography, average foveal thickness, epiretinal membrane, vitrectomy

Decreased erythrocyte superoxide dismutase in elderly men with early nuclear cataract

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Rose Rose

2015-12-01

Full Text Available BACKGROUND Imbalance between oxidative processes and antioxidant defenses has been considered to play a role in cataractogenesis, particularly in diabetes patients. Superoxide dismutase (SOD is an important precursor for oxidative stress in the human lens, and its activity is mainly dependent on the copper and zinc levels in the body. The aim of this study was to compare erythrocyte SOD, erythrocyte zinc and total serum testosterone levels in male patients with early senile nuclear cataract and evaluate the correlations between the parameters in all subjects. METHODS A community-based study of cross-sectional design was conducted at Cilandak District Primary Health Center where 52 adult and 17 elderly men with early senile nuclear cataract were chosen as the study subjects. Erythrocyte SOD, erythrocyte zinc, serum testosterone, and fasting blood glucose (FBG levels were measured in all subjects. Nuclear cataract stage was assessed with the Pentacam® instrument (Oculus, Germany. Independent Student t test and Pearson’s correlation were used to analyze the results. RESULTS Erythrocyte SOD level was significantly decreased in elderly men compared to adult men (p=0.014. Erythrocyte zinc, serum testosterone and FBG did not differ significantly in adult and elderly males (at p=0.304; p=0.145;and p=0.376, respectively. Erythrocyte SOD activity was significantly associated with erythrocyte zinc level (r=0.486; p=0.048. CONCLUSIONS Lower erythrocyte SOD activity was found in elderly males than in adult males with early nuclear cataract. There was a relationship between erythrocyte SOD and erythrocyte zinc level in elderly males with early nuclear cataract.

Decreased erythrocyte superoxide dismutase in elderly men with early nuclear cataract

Directory of Open Access Journals (Sweden)

Rose

2014-04-01

Full Text Available BACKGROUND Imbalance between oxidative processes and antioxidant defenses has been considered to play a role in cataractogenesis, particularly in diabetes patients. Superoxide dismutase (SOD is an important precursor for oxidative stress in the human lens, and its activity is mainly dependent on the copper and zinc levels in the body. The aim of this study was to compare erythrocyte SOD, erythrocyte zinc and total serum testosterone levels in male patients with early senile nuclear cataract and evaluate the correlations between the parameters in all subjects. METHODS A community-based study of cross-sectional design was conducted at Cilandak District Primary Health Center where 52 adult and 17 elderly men with early senile nuclear cataract were chosen as the study subjects. Erythrocyte SOD, erythrocyte zinc, serum testosterone, and fasting blood glucose (FBG levels were measured in all subjects. Nuclear cataract stage was assessed with the Pentacam® instrument (Oculus, Germany. Independent Student t test and Pearson’s correlation were used to analyze the results. RESULTS Erythrocyte SOD level was significantly decreased in elderly men compared to adult men (p=0.014. Erythrocyte zinc, serum testosterone and FBG did not differ significantly in adult and elderly males (at p=0.304; p=0.145;and p=0.376, respectively. Erythrocyte SOD activity was significantly associated with erythrocyte zinc level (r=0.486; p=0.048. CONCLUSIONS Lower erythrocyte SOD activity was found in elderly males than in adult males with early nuclear cataract. There was a relationship between erythrocyte SOD and erythrocyte zinc level in elderly males with early nuclear cataract.

The 10 kDa domain of human erythrocyte protein 4.1 binds the Plasmodium falciparum EBA-181 protein

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Coetzer Theresa L

2006-11-01

Full Text Available Abstract Background Erythrocyte invasion by Plasmodium falciparum parasites represents a key mechanism during malaria pathogenesis. Erythrocyte binding antigen-181 (EBA-181 is an important invasion protein, which mediates a unique host cell entry pathway. A novel interaction between EBA-181 and human erythrocyte membrane protein 4.1 (4.1R was recently demonstrated using phage display technology. In the current study, recombinant proteins were utilized to define and characterize the precise molecular interaction between the two proteins. Methods 4.1R structural domains (30, 16, 10 and 22 kDa domain and the 4.1R binding region in EBA-181 were synthesized in specific Escherichia coli strains as recombinant proteins and purified using magnetic bead technology. Recombinant proteins were subsequently used in blot-overlay and histidine pull-down assays to determine the binding domain in 4.1R. Results Blot overlay and histidine pull-down experiments revealed specific interaction between the 10 kDa domain of 4.1R and EBA-181. Binding was concentration dependent as well as saturable and was abolished by heat denaturation of 4.1R. Conclusion The interaction of EBA-181 with the highly conserved 10 kDa domain of 4.1R provides new insight into the molecular mechanisms utilized by P. falciparum during erythrocyte entry. The results highlight the potential multifunctional role of malaria invasion proteins, which may contribute to the success of the pathogenic stage of the parasite's life cycle.

Photolabeling and radioligand binding of human erythrocyte NaK-ATPase with 125I-derivatives of cymarin and digitoxigenin

International Nuclear Information System (INIS)

Lowndes, J.M.

1988-01-01

NaK-ATPase is an enzyme which maintains Na + and K + gradients across the plasma membrane of eukaryotic cells, and is specifically inhibited by cardiac glycosides. The cardiac glycoside binding site is located primarily on the catalytic α subunit but the glycoprotein β and proteolipid-γ subunits may also contribute to the structure of the site. In order to label the cardiac glycoside binding site of human erythrocytes, four photoaffinity ligands with very high specific radioactivity were synthesized. The compounds, which are abbreviated [ 125 I]AISC, [ 125 I]AIPP-GluD, [ 125 I]AIPP-GalD and [ 125 I]IA-GalD, were all effective photolabels for NaK-ATPase as shown by ouabain-protectable, covalent labeling of the α, β, and proteolipid-γ subunits. In order to study the possible existence of a very high affinity binding site in erythrocyte NaK-ATPase, a carrier-free radioligand, [ 125 I]I-TASC, was synthesized; this compound had the same structure as [ 125 I]AISC except that a light-sensitive azide group was replaced with a hydroxyl group. Competitive binding assays with cymarin against 0.2 nM [ 125 I]I-TASC suggested two classes of erythrocyte binding sites. Scatchard analysis of direct [ 125 I]I-TASC binding indicated that the very high affinity, low capacity class of erythrocyte bindings sites had a K D of 54 pM and a B max of 23 fmol/mg protein

Erythrocyte zinc levels in children with bronchial asthma.

Science.gov (United States)

Arik Yilmaz, E; Ozmen, S; Bostanci, I; Misirlioglu, E Dibek; Ertan, U

2011-12-01

Zinc deficiency may be suspected to play a role in the pathogenesis, control, and severity of asthma because of its antioxidant, antiapoptotic, and anti-inflammatory effects. We aimed to investigate whether there was any relationship between erythrocyte zinc levels and childhood asthma. The erythrocyte zinc levels of 67 asthmatic and 45 healthy children were analyzed in this case-control study. The mean concentrations of erythrocyte zinc were 1215.8 ± 145.1 µg/dl in asthma patients and 1206.9 ± 119.5 µg/dl in controls with no significant difference (P = 0.472). The erythrocyte zinc level was below 1,000 µg/dl in 6 asthmatic patients (8.9%) and 2 control group patients (4.4%). There was no relationship between erythrocyte zinc levels and duration of follow-up, severity, and control of the asthma (P > 0.05). On the other hand, patients hospitalized for an asthma attack had significantly lower erythrocyte zinc levels compared with nonhospitalized patients and the control group (P = 0.000 and P = 0.004 respectively). This study's findings indicate that asthmatic children are not a risk group for zinc deficiency. We emphasize that checking zinc levels in children who are hospitalized for an asthma attack may be useful. Copyright © 2011 Wiley Periodicals, Inc.

Altitude Acclimatization and Blood Volume: Effects of Exogenous Erythrocyte Volume Expansion

National Research Council Canada - National Science Library

Sawka, M

1996-01-01

...: (a) altitude acclimatization effects on erythrocyte volume and plasma volume; (b) if exogenous erythrocyte volume expansion alters subsequent erythrocyte volume and plasma volume adaptations; (c...

Deformability of Erythrocytes and Oxidative Damage in Alzheimer Disease

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Mukerrem Betul Yerer

2012-04-01

Full Text Available Purpose: A lowered cerebral perfusion as a consequence of hemodynamic microcirculatory insufficiency is one of the factors underlying in Alzheimer's disease, which is a neurodegenerative disorder leading to progressive cognitive impairment. Erythrocyte deformability is one of the major factors affecting the microcirculatory hemodynamics which is closely related to the oxidative damage. The aim of this study is to investigate the relationship between the erythrocyte deformability, nitric oxide levels and oxidative stress in Alzheimer's disease. Methods: The blood samples of 30 elderly people in three groups consisting of healthy control and different severities of the disease (low and severe were used. Then the erythrocytes were isolated and the deformability of erythrocytes was determined by Rheodyne SSD evaluating the elongation indexes of the erythrocytes under different shear stress. The catalase, glutathione peroxidase and plasma nitric oxide levels were measured spectrophotometric ally. Results: The plasma nitric oxide levels, catalase activities were found significantly higher and glutathione peroxidase activity was significantly lower in severe Alzheimer's disease patients compared to the control group. However, the deformability of erythrocytes was not significantly affected from these alterations. Conclusion: the oxidant-antioxidant status is dramatically changed in Alzheimer's disease patients with the severity of the disease and similar alterations were seen in the nitric oxide levels without any significant change in erythrocyte deformability. [Cukurova Med J 2012; 37(2.000: 65-75

Synergistic Effect of Rapamycin and Metformin Against Age-Dependent Oxidative Stress in Rat Erythrocytes.

Science.gov (United States)

Singh, Abhishek Kumar; Garg, Geetika; Singh, Sandeep; Rizvi, Syed Ibrahim

2017-10-01

Erythrocytes are particularly vulnerable toward age-dependent oxidative stress-mediated damage. Caloric restriction mimetics (CRMs) may provide a novel strategy for the maintenance of redox balance as well as effective treatment of age-associated diseases. Herein, we have investigated the beneficial effect of cotreatment with CRM-candidate drugs, rapamycin (an immunosuppressant drug and inhibitor of mammalian target of rapamycin) and metformin (an antidiabetic biguanide and activator of adenosine monophosphate kinase), against aging-induced oxidative stress in erythrocytes and plasma of aging rats. Male Wistar rats of age 4 (young) and 24 months (old) were coexposed to rapamycin (0.5 mg/kg body weight [b.w.]) and metformin (300 mg/kg b.w.), and data were compared with the response of rats receiving an independent exposure to these chemicals at similar doses. The exposure of individual candidate drugs significantly reversed the age-dependent alterations in the endpoints associated with oxidative stress such as reactive oxygen species, ferric reducing ability of plasma, malondialdehyde, reduced glutathione, plasma membrane redox system, plasma protein carbonyl, and acetyl cholinesterase in erythrocytes and plasma of aging rats. However, the cotreatment with rapamycin and metformin showed a significant augmented effect compared with individual drug interventions on reversal of these age-dependent biomarkers of oxidative stress, suggesting a synergistic response. Thus, the findings open up further possibilities for the design of new combinatorial therapies to prevent oxidative stress- and age-associated health problems.

Ferrokinetic and erythrocyte survival studies in healthy and anemic cats

Energy Technology Data Exchange (ETDEWEB)

Madewell, B.R.; Holmes, P.H.; Onions, D.E.

1983-03-01

Erythrocyte survival and ferrokinetic studies were adapted to the cat. For 5 clinically healthy 4- to 9-month-old cats, mean /sup 51/Cr-labeled erythrocyte survival was 144 hours, and mean plasma /sup 59/Fe-labeled transferrin disappearance halftime was 51 minutes. Erythrocyte use of radioiron was rapid and efficient, with 50% to 80% of labeled iron incorporated into the erythron by 100 hours after injection into the cat. Six cats with feline leukemia virus infection were studied. For 2 cats with erythroid aplasia associated with C subgroup of feline leukemia virus, erythrocyte survival times were similar to those determined for the healthy cats, but plasma radioiron disappearance half time and erythrocyte use of radioiron were markedly diminished.

Ferrokinetic and erythrocyte survival studies in healthy and anemic cats

International Nuclear Information System (INIS)

Madewell, B.R.; Holmes, P.H.; Onions, D.E.

1983-01-01

Erythrocyte survival and ferrokinetic studies were adapted to the cat. For 5 clinically healthy 4- to 9-month-old cats, mean 51 Cr-labeled erythrocyte survival was 144 hours, and mean plasma 59 Fe-labeled transferrin disappearance halftime was 51 minutes. Erythrocyte use of radioiron was rapid and efficient, with 50% to 80% of labeled iron incorporated into the erythron by 100 hours after injection into the cat. Six cats with feline leukemia virus infection were studied. For 2 cats with erythroid aplasia associated with C subgroup of feline leukemia virus, erythrocyte survival times were similar to those determined for the healthy cats, but plasma radioiron disappearance half time and erythrocyte use of radioiron were markedly diminished

The Red Blood Cell Membrane of Preterm Infants in the Early Neonatal Period

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S. A. Perepelitsa

2014-01-01

Full Text Available Objective: to study the nanostructure of red blood cell membranes and erythrocyte index in preterm neonatal infants.Subjects and methods. The trial enrolled 47 neonatal infants, including 33 preterm infants who were included in a study group and 14 fullterm infants who formed a comparative group. The gestational age of the preterm infants was 33.3±1.9 weeks and the birth weight was 2065.4±304.8 g. Red blood cell counts, hemoglobin, and erythrocyte indices were estimat ed and the red blood cells were examined using an atomicforce microscope.Results. At birth, the preterm infants showed macrocytosis, intrauterine poikylocytosis, and the impaired nanostructure of red blood cell membranes. Intrauterine hypoxia affects the red blood cell membrane nanostructures: a phospholipid bilayer and a spectrin matrix, without damaging the membrane protein component. The detected changes are reversible and directed to maintaining the functional ability of red blood cells in a critical situation. At birth, gestational age, a baby's weight, hemoglobin, and blood cholesterol and standard bicarbonate levels influence the parameters of a red blood cell component. The early neonatal period was characterized by an active process on the red blood cell membranes and a change of morphological forms, suggesting the continuing postnatal rearrangement of erythropoiesis and a preterm infant's adaptation to new environmental conditions.

Determination of electric field threshold for electrofusion of erythrocyte ghosts. Comparison of pulse-first and contact-first protocols.

OpenAIRE

Wu, Y; Montes, J G; Sjodin, R A

1992-01-01

Rabbit erythrocyte ghosts were fused by means of electric pulses to determine the electrofusion thresholds for these membranes. Two protocols were used to investigate fusion events: contact-first, and pulse-first. Electrical capacitance discharge (CD) pulses were used to induce fusion. Plots of fusion yield vs peak field strength yielded curves that intersected the field strength axis at positive values (pseudothresholds) which depended on the protocol and decay half time of the pulses. It wa...

Design and evaluation of antimalarial peptides derived from prediction of short linear motifs in proteins related to erythrocyte invasion.

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Alessandra Bianchin

Full Text Available The purpose of this study was to investigate the blood stage of the malaria causing parasite, Plasmodium falciparum, to predict potential protein interactions between the parasite merozoite and the host erythrocyte and design peptides that could interrupt these predicted interactions. We screened the P. falciparum and human proteomes for computationally predicted short linear motifs (SLiMs in cytoplasmic portions of transmembrane proteins that could play roles in the invasion of the erythrocyte by the merozoite, an essential step in malarial pathogenesis. We tested thirteen peptides predicted to contain SLiMs, twelve of them palmitoylated to enhance membrane targeting, and found three that blocked parasite growth in culture by inhibiting the initiation of new infections in erythrocytes. Scrambled peptides for two of the most promising peptides suggested that their activity may be reflective of amino acid properties, in particular, positive charge. However, one peptide showed effects which were stronger than those of scrambled peptides. This was derived from human red blood cell glycophorin-B. We concluded that proteome-wide computational screening of the intracellular regions of both host and pathogen adhesion proteins provides potential lead peptides for the development of anti-malarial compounds.

Deformation-induced release of ATP from erythrocytes in a poly(dimethylsiloxane)-based microchip with channels that mimic resistance vessels.

Science.gov (United States)

Price, Alexander K; Fischer, David J; Martin, R Scott; Spence, Dana M

2004-08-15

The ability of nitric oxide to relax smooth muscle cells surrounding resistance vessels in vivo is well documented. Here, we describe a series of studies designed to quantify amounts of adenosine triphosphate (ATP), a known stimulus of NO production in endothelial cells, released from erythrocytes that are mechanically deformed as these cells traverse microbore channels in lithographically patterned microchips. Results indicate that micromolar amounts of ATP are released from erythrocytes flowing through channels having cross sectional dimensions of 60 x 38 micron (2.22 +/- 0.50 microM ATP). Microscopic images indicate that erythrocytes, when being pumped through the microchip channels, migrate toward the center of the channels, leaving a cell-free or skimming layer at the walls of the channel, a profile known to exist in circulatory vessels in vivo. A comparison of the amounts of ATP released from RBCs mechanically deformed in microbore tubing (2.54 +/- 0.15 microM) vs a microchip (2.59 +/- 0.32 microM) suggests that channels in microchips may serve as functional biomimics of the microvasculature. Control studies involving diamide, a membrane-stiffening agent, suggest that the RBC-derived ATP is not due to cell lysis but rather physical deformation.

Use of 86Rb and 22Na in assaying active and cotransport activities in hum erythrocytes in a biracial population

International Nuclear Information System (INIS)

Sharma, C.; Dalferes, E.R. Jr; Freedman, D.S.; Asamoah, A.; Berenson, G.S.

1988-01-01

A defect in Na/sup +/-K/sup +/ transport across the red cell membrane has been shown to be associated with essential hypertension. A sensitive assay system to measure active, co- and countertransport systems in erythrocytes from normotensive adults was developed. Active, co- and countertransport systems in the erythrocytes were assayed by measuring the influx of radioactive /sup 22/Na/sup +/ and /sup 86/Rb/ sup +/. In the biracial (black-white) population group studied, analysis of variance of the active transport showed a significant race effect. Cotransport activity showed age by race interaction and age by sex. Cotransport activity was significantly higher in whites than blacks. The results suggest a subtle difference in Na/sup +/-K/sup +/ transport systems between blacks and whites, and these variations may be related to differences for susceptibility to essential hypertension

Morphometric analysis of erythrocytes from patients with thalassemia using tomographic diffractive microscopy

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Lin, Yang-Hsien; Huang, Shin-Shyang; Wu, Shang-Ju; Sung, Kung-Bin

2017-11-01

Complete blood count is the most common test to detect anemia, but it is unable to obtain the abnormal shape of erythrocytes, which highly correlates with the hematologic function. Tomographic diffractive microscopy (TDM) is an emerging technique capable of quantifying three-dimensional (3-D) refractive index (RI) distributions of erythrocytes without labeling. TDM was used to characterize optical and morphological properties of 172 erythrocytes from healthy volunteers and 419 erythrocytes from thalassemic patients. To efficiently extract and analyze the properties of erythrocytes, we developed an adaptive region-growing method for automatically delineating erythrocytes from 3-D RI maps. The thalassemic erythrocytes not only contained lower hemoglobin content but also showed doughnut shape and significantly lower volume, surface area, effective radius, and average thickness. A multi-indices prediction model achieved perfect accuracy of diagnosing thalassemia using four features, including the optical volume, surface-area-to-volume ratio, sphericity index, and surface area. The results demonstrate the ability of TDM to provide quantitative, hematologic measurements and to assess morphological features of erythrocytes to distinguish healthy and thalassemic erythrocytes.

Bio-field array: a dielectrophoretic electromagnetic toroidal excitation to restore and maintain the golden ratio in human erythrocytes.

Science.gov (United States)

Purnell, Marcy C; Butawan, Matthew B A; Ramsey, Risa D

2018-06-01

Erythrocytes must maintain a biconcave discoid shape in order to efficiently deliver oxygen (O 2 ) molecules and to recycle carbon dioxide (CO 2 ) molecules. The erythrocyte is a small toroidal dielectrophoretic (DEP) electromagnetic field (EMF) driven cell that maintains its zeta potential (ζ) with a dielectric constant (ԑ) between a negatively charged plasma membrane surface and the positively charged adjacent Stern layer. Here, we propose that zeta potential is also driven by both ferroelectric influences (chloride ion) and ferromagnetic influences (serum iron driven). The Golden Ratio, a function of Phi φ, offers a geometrical mathematical measure within the distinct and desired curvature of the red blood cell that is governed by this zeta potential and is required for the efficient recycling of CO 2 in our bodies. The Bio-Field Array (BFA) shows potential to both drive/fuel the zeta potential and restore the Golden Ratio in human erythrocytes thereby leading to more efficient recycling of CO 2 . Live Blood Analyses and serum CO 2 levels from twenty human subjects that participated in immersion therapy sessions with the BFA for 2 weeks (six sessions) were analyzed. Live Blood Analyses (LBA) and serum blood analyses performed before and after the BFA immersion therapy sessions in the BFA pilot study participants showed reversal of erythrocyte rheological alterations (per RBC metric; P = 0.00000075), a morphological return to the Golden Ratio and a significant decrease in serum CO 2 (P = 0.017) in these participants. Immersion therapy sessions with the BFA show potential to modulate zeta potential, restore this newly defined Golden Ratio and reduce rheological alterations in human erythrocytes. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Effect of internal limiting membrane peeling on the development of epiretinal membrane after pars plana vitrectomy for primary rhegmatogenous retinal detachment.

Science.gov (United States)

Nam, Ki Yup; Kim, Jung Yeul

2015-05-01

To investigate the difference in the occurrence of postoperative epiretinal membranes (ERMs) in vitrectomy for rhegmatogenous retinal detachment with and without peeling of the internal limiting membrane (ILM). The medical records of the 135 patients, who underwent vitrectomy for primary rhegmatogenous retinal detachment from November 2007 to August 2011, were analyzed retrospectively. Of the subjects, 70 patients underwent ILM peeling during the surgery and 65 did not. The best-corrected visual acuity, fundus photograph, and optical coherence tomography were collected 3, 6, and 12 months postoperatively. The relationship between ILM peeling and the preoperative findings of rhegmatogenous retinal detachment and development of a postoperative ERM was analyzed. No ERM occurred in the ILM peeling group, whereas an ERM occurred in 14 of 65 patients who underwent vitrectomy without ILM peeling (21.5%). This difference was significant (P peeling group and was significantly higher 12 months postoperatively (P = 0.03). Internal limiting membrane peeling seems to prevent the occurrence of a postoperative ERM in patients with primary rhegmatogenous retinal detachment.

The Role and Mechanism of Erythrocyte Invasion by Francisella tularensis

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Deanna M. Schmitt

2017-05-01

Full Text Available Francisella tularensis is an extremely virulent bacterium that can be transmitted naturally by blood sucking arthropods. During mammalian infection, F. tularensis infects numerous types of host cells, including erythrocytes. As erythrocytes do not undergo phagocytosis or endocytosis, it remains unknown how F. tularensis invades these cells. Furthermore, the consequence of inhabiting the intracellular space of red blood cells (RBCs has not been determined. Here, we provide evidence indicating that residing within an erythrocyte enhances the ability of F. tularensis to colonize ticks following a blood meal. Erythrocyte residence protected F. tularensis from a low pH environment similar to that of gut cells of a feeding tick. Mechanistic studies revealed that the F. tularensis type VI secretion system (T6SS was required for erythrocyte invasion as mutation of mglA (a transcriptional regulator of T6SS genes, dotU, or iglC (two genes encoding T6SS machinery severely diminished bacterial entry into RBCs. Invasion was also inhibited upon treatment of erythrocytes with venom from the Blue-bellied black snake (Pseudechis guttatus, which aggregates spectrin in the cytoskeleton, but not inhibitors of actin polymerization and depolymerization. These data suggest that erythrocyte invasion by F. tularensis is dependent on spectrin utilization which is likely mediated by effectors delivered through the T6SS. Our results begin to elucidate the mechanism of a unique biological process facilitated by F. tularensis to invade erythrocytes, allowing for enhanced colonization of ticks.

Single-Molecule Fluorescence Studies of Membrane Transporters Using Total Internal Reflection Microscopy.

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Goudsmits, Joris M H; van Oijen, Antoine M; Slotboom, Dirk J

2017-01-01

Cells are delineated by a lipid bilayer that physically separates the inside from the outer environment. Most polar, charged, or large molecules require proteins to reduce the energetic barrier for passage across the membrane and to achieve transport rates that are relevant for life. Here, we describe techniques to visualize the functioning of membrane transport proteins with fluorescent probes at the single-molecule level. First, we explain how to produce membrane-reconstituted transporters with fluorescent labels. Next, we detail the construction of a microfluidic flow cell to image immobilized proteoliposomes on a total internal reflection fluorescence microscope. We conclude by describing the methods that are needed to analyze fluorescence movies and obtain useful single-molecule data. © 2017 Elsevier Inc. All rights reserved.

Dietary olive oil effect on antioxidant status and fatty acid profile in the erythrocyte of 2,4-D- exposed rats

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Nakbi Amel

2010-08-01

Full Text Available Abstract Background Oxidative stress produced by reactive oxygen species (ROS has been linked to the development of several diseases such as cardiovascular, cancer, and neurodegenerative diseases. This study investigates the possible protective effect of extra virgin olive oil (EVOO, lipophilic fraction (OOLF and hydrophilic fraction (OOHF on oxidative stress and fatty acid profile of erythrocytes in 2,4-D treated rats. Methods Male Wistar rats were divided randomly into eight groups: control (C, (2,4-D at a dose of 5 mg/kg b.w., (2,4-D/EVOO was given 2,4-D plus EVOO, (2,4-D/OOHF that received 2,4-D plus hydrophilic fraction, (2,4-D/OOLF treated with 2,4-D plus lipophilic fraction, (EVOO that received only EVOO, (OOHF was given hydrophilic fraction and (OOLF treated with lipophilic fraction. These components were daily administered by gavages for 4 weeks. Results 2,4-D treatment lead to decrease of antioxidant enzyme activities, namely, superoxide dismutase (SOD, catalase (CAT, glutathione peroxidase (GPx and glutathione reductase (GR associated with a higher amount of MDA level. Erythrocyte membranes' fatty acid composition was also significantly modified with 2,4-D exposure. EVOO and hydrophilic fraction supplemented to rats with or not 2,4-D treatment enhanced the antioxidant enzyme activities and reduced the MDA level. However, lipophilic fraction did not show any improvement in oxidative damage induced by 2,4-D in spite its richness in MUFA and vitamins. Conclusion EVOO administered to 2,4-D-treated rats protected erythrocyte membranes against oxidative damage by means of preventing excessive lipid peroxidation to increase the MUFA composition and increase maintaining antioxidants enzymes at normal concentrations.

Interaction of lectins with membrane receptors on erythrocyte surfaces.

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Sung, L A; Kabat, E A; Chien, S

1985-08-01

The interactions of human genotype AO erythrocytes (red blood cells) (RBCs) with N-acetylgalactosamine-reactive lectins isolated from Helix pomatia (HPA) and from Dolichos biflorus (DBA) were studied. Binding curves obtained with the use of tritium-labeled lectins showed that the maximal numbers of lectin molecules capable of binding to human genotype AO RBCs were 3.8 X 10(5) and 2.7 X 10(5) molecules/RBC for HPA and DBA, respectively. The binding of one type of lectin may influence the binding of another type. HPA was found to inhibit the binding of DBA, but not vice versa. The binding of HPA was weakly inhibited by a beta-D-galactose-reactive lectin isolated from Ricinus communis (designated RCA1). Limulus polyphemus lectin (LPA), with specificity for N-acetylneuraminic acid, did not influence the binding of HPA but enhanced the binding of DBA. About 80% of LPA receptors (N-acetylneuraminic acid) were removed from RBC surfaces by neuraminidase treatment. Neuraminidase treatment of RBCs resulted in increases of binding of both HPA and DBA, but through different mechanisms. An equal number (7.6 X 10(5) of new HPA sites were generated on genotypes AO and OO RBCs by neuraminidase treatment, and these new sites accounted for the enhancement (AO cells) and appearance (OO cells) of hemagglutinability by HPA. Neuraminidase treatment did not generate new DBA sites, but increased the DBA affinity for the existing receptors; as a result, genotype AO cells increased their hemagglutinability by DBA, while OO cells remained unagglutinable. The use of RBCs of different genotypes in binding assays with 3H-labeled lectins of known specificities provides an experimental system for studying cell-cell recognition and association.

The role of blood cell membrane lipids on the mode of action of HIV-1 fusion inhibitor sifuvirtide

International Nuclear Information System (INIS)

Matos, Pedro M.; Freitas, Teresa; Castanho, Miguel A.R.B.; Santos, Nuno C.

2010-01-01

Research highlights: → Sifuvirtide interacts with erythrocyte and lymphocyte membrane in a concentration dependent manner by decreasing its dipole potential. → Dipole potential variations in lipid vesicles show sifuvirtide's lipid selectivity towards saturated phosphatidylcholines. → This peptide-membrane interaction may direct the drug towards raft-like membrane domains where the receptors used by HIV are located, facilitating its inhibitory action. -- Abstract: Sifuvirtide is a gp41 based peptide that inhibits HIV-1 fusion with the host cells and is currently under clinical trials. Previous studies showed that sifuvirtide partitions preferably to saturated phosphatidylcholine lipid membranes, instead of fluid-phase lipid vesicles. We extended the study to the interaction of the peptide with circulating blood cells, by using the dipole potential sensitive probe di-8-ANEPPS. Sifuvirtide decreased the dipole potential of erythrocyte and lymphocyte membranes in a concentration dependent manner, demonstrating its interaction. Also, the lipid selectivity of the peptide towards more rigid phosphatidylcholines was confirmed based on the dipole potential variations. Overall, the interaction of the peptide with the cell membranes is a contribution of different lipid preferences that presumably directs the peptide towards raft-like domains where the receptors are located, facilitating the reach of the peptide to its molecular target, the gp41 in its pre-fusion conformation.

Erythrocyte signal transduction pathways, their oxygenation dependence and functional significance.

Science.gov (United States)

Barvitenko, Nadezhda N; Adragna, Norma C; Weber, Roy E

2005-01-01

Erythrocytes play a key role in human and vertebrate metabolism. Tissue O2 supply is regulated by both hemoglobin (Hb)-O2 affinity and erythrocyte rheology, a key determinant of tissue perfusion. Oxygenation-deoxygenation transitions of Hb may lead to re-organization of the cytoskeleton and signalling pathways activation/deactivation in an O2-dependent manner. Deoxygenated Hb binds to the cytoplasmic domain of the anion exchanger band 3, which is anchored to the cytoskeleton, and is considered a major mechanism underlying the oxygenation-dependence of several erythrocyte functions. This work discusses the multiple modes of Hb-cytoskeleton interactions. In addition, it reviews the effects of Mg2+, 2,3-diphosphoglycerate, NO, shear stress and Ca2+, all factors accompanying the oxygenation-deoxygenation cycle in circulating red cells. Due to the extensive literature on the subject, the data discussed here, pertain mainly to human erythrocytes whose O2 affinity is modulated by 2,3-diphosphoglycerate, ectothermic vertebrate erythrocytes that use ATP, and to bird erythrocytes that use inositol pentaphosphate. Copyright 2005 S. Karger AG, Basel.

Macular Hole Surgery with Internal Limiting Membrane Peeling Facilitated by Membrane-Blue® versus Membrane-Blue-Dual®: A Retrospective Comparative Study

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Uri Soiberman

2016-01-01

Full Text Available Background. This study aims to compare the outcome of macular hole (MH surgery with internal limiting membrane (ILM peeling facilitated by two different vital dyes. Methods. This was a retrospective chart review. The group designated “group-MB” underwent pars plana vitrectomy with ILM peeling facilitated by Membrane-Blue (MB, whereas in “group-MBD,” the vital dye used was Membrane-Blue-Dual (MBD. Results. Seventy-four eyes comprised the study population: 53 in group-MB and 21 in group-MBD. There was no difference in the rate of macular hole closure in group-MB or group-MBD: 71.2% closed MHs compared to 66.7%, respectively (p=0.7. Postoperative visual improvement was of a higher magnitude in the MBD group compared to the MB group: −0.34±0.81 logMAR versus 0.01±0.06 logMAR, respectively (p=0.003. Conclusions. In this study, MBD led to better visual results that may be related to better staining characteristics or lesser toxicity compared to MB.

Paired Chicken and Mammalian Erythrocyte Indicator Systems for ...

African Journals Online (AJOL)

A retrospective flock health analysis revealed that the higher titres were associated with confirmable Newcastle Disease (ND) outbreaks in the affected flocks. These findings therefore suggested that the use of standardised guinea pig erythrocytes in parallel with chicken erythrocytes as indicators, might facilitate field ND ...

Erythrocyte survival studies in a rat myelogenous leukemia

International Nuclear Information System (INIS)

Derelanko, M.J.; Meagher, R.C.; Lobue, J.; Khouri, J.A.; Gordon, A.S.

1982-01-01

To determine the extent intrinsic erythrocyte defects and/or extrinsic factors were involved in anemia of rats bearing Shay chloroleukemia (SCL), survival of 3 H-DFP labeled erythrocytes was studied in leukemic and nonleukemic hosts. Red blood cells labeled before induction of leukemia, were rapidly lost from the peripheral circulation of SCL rats in terminal stages of disease. However, labeled erythrocytes from terminal SCL animals displayed normal lifespans when transfused into nonleukemic controls. Thus the anemia of this leukemia probably resulted from extrinsic factors associated with the leukemic process. Hemorrhage appeared to be primarily responsible for the anemia of this disease

Change of the NADPH depending superoxide producing and ferri hemoglobin reducing activities of cytochrome b558 from spleen cells and erythrocytes membranes induced by the radiation of different character

International Nuclear Information System (INIS)

Melkonyan, L.G.; Simonyan, R.M.; Simonyan, M.A.; Sekoyan, E.S.

2009-01-01

After the X radiation, UVA radiation and ultrasound radiation of new isoforms of cytochrome cyt b 5 58 from rats erythrocyte membranes - EM (cyt b 5 58III) and from spleen cell membranes (SCM) in vitro, as well as after the radiation of EM ex vivo, the suppression of both NADPH depending O 2 - producing and ferrihemoglobin (ferriHb)-reducing activities of cyt b 5 58 from EM and SCM in homogeneous (in solution) and heterogeneous phases (in EM and SCM) at various scopes takes place. These changes are associated with the destabilization of EM and SCM, conditioned by the change of the aggregation degree of these hemoproteins in EM and SCM, hemoproteins as a result of the influence of the hydrogen peroxide formed during radiolysis and photolysis of the water medium. After He-Ne laser radiation of the cyt b 5 58 from EM and SCM in vitro an increase of the NADPH depending O 2 - producing and ferriHb-reducing activities of the cyt b 5 58 from EM and SCM in homogenous and heterogeneous phases (in membranes) takes place. It is supposed that the suppression (by X-, UVA- and US-radiation) and the stimulation (by He-Ne laser radiation) of the immune system activity and the oxygen homeostasis are associated with the corresponding decrease and increase of the NADPH depending O 2 - producing and ferriHb-reducings activity of the new isoforms of cyt b 5 58 from EM and SCM in homogeneous and heterogeneous phases

[Optical coherence tomography and microperimetry after internal limiting membrane peeling for epiretinal membrane].

Science.gov (United States)

Grimbert, P; Lebreton, O; Weber, M

2014-06-01

To evaluate the anatomical and functional consequences of internal limiting membrane (ILM) peeling in epiretinal membrane (ERM) surgery. Retrospective single-center study including consecutive patients operated on for idiopathic ERM. The integrity of the ILM was assessed by ILM Blue® staining after removal of the ERM: either the peeling was spontaneous (group 1) or a complementary peeling was required (group 2). Pre- and post-operatively (1 and 6 months), all patients were analyzed using visual acuity, SD-OCT (Spectralis HRA OCT, Heidelberg, Germany) and microperimetry (OPKO/OTI, Miami, USA). Twenty-one eyes of 21 patients were included: 12 "active ILM peelings" and 9 "spontaneous peelings". In both groups, visual acuity increased significantly after surgery. Microperimetry revealed more microscotomata at 1 and 6 months for active peeling (Ppeeling is frequently performed to reduce ERM recurrence. Despite lack of effect on visual acuity, active ILM peeling increases the incidence of microscotomas related to the site where the ERM or ILM is grasped. Active ILM peeling may be responsible for postoperative visual discomfort related to microscopic trauma during peeling. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Red Blood Cell Membrane-Cloaked Nanoparticles For Drug Delivery

Science.gov (United States)

Carpenter, Cody Westcott

Herein we describe the development of the Red Blood Cell coated nanoparticle, RBC-NP. Purified natural erythrocyte membrane is used to coat drug-loaded poly(lacticco-glycolic acid) (PLGA). Synthetic PLGA co-polymer is biocompatible and biodegradable and has already received US FDA approval for drug-delivery and diagnostics. This work looks specifically at the retention of immunosuppressive proteins on RBC-NPs, right-sidedness of natural RBC membranes interfacing with synthetic polymer nanoparticles, sustained and retarded drug release of RBC-NPs as well as further surface modification of RBC-NPs for increased targeting of model cancer cell lines.

3D visualization of the internal nanostructure of polyamide thin films in RO membranes

KAUST Repository

Pacheco Oreamuno, Federico

2015-11-02

The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.

3D visualization of the internal nanostructure of polyamide thin films in RO membranes

KAUST Repository

Pacheco Oreamuno, Federico; Sougrat, Rachid; Reinhard, Martin; Leckie, James O.; Pinnau, Ingo

2015-01-01

The front and back surfaces of fully aromatic polyamide thin films isolated from reverse osmosis (RO) membranes were characterized by TEM, SEM and AFM. The front surfaces were relatively rough showing polyamide protuberances of different sizes and shapes; the back surfaces were all consistently smoother with very similar granular textures formed by polyamide nodules of 20–50 nm. Occasional pore openings of approximately the same size as the nodules were observed on the back surfaces. Because traditional microscopic imaging techniques provide limited information about the internal morphology of the thin films, TEM tomography was used to create detailed 3D visualizations that allowed the examination of any section of the thin film volume. These tomograms confirmed the existence of numerous voids within the thin films and revealed structural characteristics that support the water permeance difference between brackish water (BWRO) and seawater (SWRO) RO membranes. Consistent with a higher water permeance, the thin film of the BWRO membrane ESPA3 contained relatively more voids and thinner sections of polyamide than the SWRO membrane SWC3. According to the tomograms, most voids originate near the back surface and many extend all the way to the front surface shaping the polyamide protuberances. Although it is possible for the internal voids to be connected to the outside through the pore openings on the back surface, it was verified that some of these voids comprise nanobubbles that are completely encapsulated by polyamide. TEM tomography is a powerful technique for investigating the internal nanostructure of polyamide thin films. A comprehensive knowledge of the nanostructural distribution of voids and polyamide sections within the thin film may lead to a better understanding of mass transport and rejection mechanisms in RO membranes.

Identification of Stages of Erythroid Differentiation in Bone Marrow and Erythrocyte Subpopulations in Blood Circulation that Are Preferentially Lost in Autoimmune Hemolytic Anemia in Mouse.

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Sreoshi Chatterjee

Full Text Available Repeated weekly injections of rat erythrocytes produced autoimmune hemolytic anemia (AIHA in C57BL/6 mice after 5-6 weeks. Using the double in vivo biotinylation (DIB technique, recently developed in our laboratory, turnover of erythrocyte cohorts of different age groups during AIHA was monitored. Results indicate a significant decline in the proportion of reticulocytes, young and intermediate age groups of erythrocytes, but a significant increase in the proportion of old erythrocytes in blood circulation. Binding of the autoantibody was relatively higher to the young erythrocytes and higher levels of intracellular reactive oxygen species (ROS were also seen in these cells. Erythropoietic activity in the bone marrows and the spleen of AIHA induced mice was examined by monitoring the relative proportion of erythroid cells at various stages of differentiation in these organs. Cells at different stages of differentiation were enumerated flow cytometrically by double staining with anti-Ter119 and anti-transferrin receptor (CD71 monoclonal antibodies. Erythroid cells in bone marrow declined significantly in AIHA induced mice, erythroblast C being most affected (50% decline. Erythroblast C also recorded high intracellular ROS level along with increased levels of membrane-bound autoantibody. No such decline was observed in spleen. A model of AIHA has been proposed indicating that binding of autoantibodies may not be a sufficient condition for destruction of erythroid cells in bone marrow and in blood circulation. Last stage of erythropoietic differentiation in bone marrow and early stages of erythrocytes in blood circulation are specifically susceptible to removal in AIHA.

In Vitro Protective Effect of Phikud Navakot Extraction on Erythrocyte

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Kanchana Kengkoom

2016-01-01

Full Text Available Phikud Navakot (PN, Thai herbal remedy in National List of Essential Medicines, has been claimed to reduce many cardiovascular symptoms especially dizziness and fainting. Apart from blood supply, erythrocyte morphology, in both shape and size, is one of the main consideration factors in cardiovascular diseases and may be affected by vascular oxidative stress. However, little is known about antioxidative property of PN on erythrocyte to preserve red blood cell integrity. In this study, 1,000 μM hydrogen peroxide-induced oxidative stress was conducted on sheep erythrocyte. Three doses of PN (1, 0.5, and 0.25 mg/mL and 10 μM of ascorbic acid were compared. The released hemoglobin absorbance was measured to demonstrate hemolysis. Electron microscopic and immunohistochemical studies were also performed to characterize dysmorphic erythrocyte and osmotic ability in relation to aquaporin- (AQP- 1 expression, respectively. The results revealed that all doses of PN and ascorbic acid decreased the severity of dysmorphic erythrocyte, particularly echinocyte, acanthocyte, knizocyte, codocyte, clumping, and other malformations. However, the most effective was 0.5 mg/mL PN dosage. In addition, hydrostatic pressure may be increased in dysmorphic erythrocyte in association with AQP-1 upregulation. Our results demonstrated that PN composes antioxidative effect to maintain the integrity and osmotic ability on sheep erythrocyte.

A sequence in subdomain 2 of DBL1α of Plasmodium falciparum erythrocyte membrane protein 1 induces strain transcending antibodies.

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Karin Blomqvist

Full Text Available Immunity to severe malaria is the first level of immunity acquired to Plasmodium falciparum. Antibodies to the variant antigen PfEMP1 (P. falciparum erythrocyte membrane protein 1 present at the surface of the parasitized red blood cell (pRBC confer protection by blocking microvascular sequestration. Here we have generated antibodies to peptide sequences of subdomain 2 of PfEMP1-DBL1α previously identified to be associated with severe or mild malaria. A set of sera generated to the amino acid sequence KLQTLTLHQVREYWWALNRKEVWKA, containing the motif ALNRKE, stained the live pRBC. 50% of parasites tested (7/14 were positive both in flow cytometry and immunofluorescence assays with live pRBCs including both laboratory strains and in vitro adapted clinical isolates. Antibodies that reacted selectively with the sequence REYWWALNRKEVWKA in a 15-mer peptide array of DBL1α-domains were also found to react with the pRBC surface. By utilizing a peptide array to map the binding properties of the elicited anti-DBL1α antibodies, the amino acids WxxNRx were found essential for antibody binding. Complementary experiments using 135 degenerate RDSM peptide sequences obtained from 93 Ugandan patient-isolates showed that antibody binding occurred when the amino acids WxLNRKE/D were present in the peptide. The data suggests that the ALNRKE sequence motif, associated with severe malaria, induces strain-transcending antibodies that react with the pRBC surface.

Recurrence rate and need for reoperation after surgery with or without internal limiting membrane removal for the treatment of the epiretinal membrane.

Science.gov (United States)

De Novelli, Fernando José; Goldbaum, Mauro; Monteiro, Mario Luiz Ribeiro; Aggio, Fabio Bom; Nóbrega, Mario Junqueira; Takahashi, Walter Yukihiko

2017-01-01

To compare the recurrence rate and need for reoperation after epiretinal membrane surgery with and without removal of the internal limiting membrane. In this retrospective study, 125 patients operated for epiretinal membrane removal were evaluated, with a minimum 6-month follow-up. Removal of the epiretinal membrane (ERM) was performed in 78 patients, while 47 had removal of the epiretinal membrane associated with internal limiting membrane peeling (ERM + ILM). The mean age in the ERM group was 65.8 years old, ranging from 41 to 80 years old. In the ERM + ILM group, the mean age was 67.2 years old, ranging from 52 to 82 years old. The mean preoperative visual acuity in the ERM group was 20/80p, and in the ERM + ILM group, it was 20/80. The mean postoperative visual acuity in both groups was 20/30. The mean preoperative macular thickness in the ERM group was 467 µm ranging from 281 to 663 µm; in the ERM + ILM group, the preoperative macular thickness was 497 µm, ranging from 172 to 798 µm. After surgery, a reduction in macular thickness was observed in both groups. In the ERM group, the mean macular thickness reduction was 361 ± 101. µm, whereas in the ERM + ILM group, it was 367 ± 75.2 µm. Twenty-two patients presented with a recurrence of epiretinal membrane, of which 16 (20.5%) were from the ERM group and 6 (12.8%) were from the ERM + ILM group (p = 0.39); one patient (2%) was retreated in the ERM + ILM group, whereas 5 patients (6%) where retreated in the ERM group. We postulate that ILM peeling for the treatment of epiretinal membrane is not a relevant factor either for visual recovery or macular thickness reduction, but it may reduce the recurrence and reoperation rate.

Dietary indicaxanthin from cactus pear (Opuntia ficus-indica L. Mill) fruit prevents eryptosis induced by oxysterols in a hypercholesterolaemia-relevant proportion and adhesion of human erythrocytes to endothelial cell layers.

Science.gov (United States)

Tesoriere, Luisa; Attanzio, Alessandro; Allegra, Mario; Livrea, Maria A

2015-08-14

Toxic oxysterols in a hypercholesterolaemia-relevant proportion cause suicidal death of human erythrocytes or eryptosis. This process proceeds through early production of reactive oxygen species (ROS), release of prostaglandin (PGE2) and opening of PGE2-dependent Ca channels, membrane phosphatidylserine (PS) externalisation, and cell shrinkage. The present study was the first to reveal that a bioavailable phytochemical, indicaxanthin (Ind) from cactus pear fruit, in a concentration range (1.0-5.0 μM) consistent with its plasma level after a fruit meal, prevents PS externalisation and cell shrinkage in a dose-dependent manner when incubated with isolated healthy human erythrocytes exposed to an oxysterol mixture for 48 h. Dietary Ind inhibited ROS production, glutathione (GSH) depletion, PGE2 release and Ca2+ entry. Ind alone did not modify the erythrocyte redox environment or affect other parameters. Ex vivo spiking of normal human blood with the oxysterol mixture for 48 h induced eryptosis, resulting in the production of ROS and decreased levels of GSH, which was prevented by concurrent exposure to 5 μm-Ind. The adherence of eryptotic erythrocytes to the endothelium causes vascular tissue injury. Erythrocytes isolated from blood incubated with the oxysterol mixture plus 5 μm-Ind did not adhere to endothelial cell monolayers. Eryptotic erythrocytes may contribute to thrombotic complications in hypercholesterolaemia. Our findings suggest the positive effects of diets containing Ind on erythrocytes in hypercholesterolaemic subjects.

Erythrocyte nanovesicles: Biogenesis, biolo

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Gamaleldin I. Harisa

2017-01-01

Full Text Available Nanovesicles (NVs represent a novel transporter for cell signals to modify functions of target cells. Therefore, NVs play many roles in both physiological and pathological processes. This report highlights biogenesis, composition and biological roles of erythrocytes derived nanovesicles (EDNVs. Furthermore, we address utilization of EDNVs as novel drug delivery cargo as well as therapeutic target. EDNVs are lipid bilayer vesicles rich in phospholipids, proteins, lipid raft, and hemoglobin. In vivo EDNVs biogenesis is triggered by an increase of intracellular calcium levels, ATP depletion and under effect of oxidative stress conditions. However, in vitro production of EDNVs can be achieved via hypotonic treatment and extrusion of erythrocyte. NVs can be used as biomarkers for diagnosis, monitoring of therapy and drug delivery system. Many therapeutic agents are suggested to decrease NVs biogenesis.

Fabrication of hybrid graphene oxide/polyelectrolyte capsules by means of layer-by-layer assembly on erythrocyte cell templates

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Joseba Irigoyen

2015-12-01

Full Text Available A novel and facile method was developed to produce hybrid graphene oxide (GO–polyelectrolyte (PE capsules using erythrocyte cells as templates. The capsules are easily produced through the layer-by-layer technique using alternating polyelectrolyte layers and GO sheets. The amount of GO and therefore its coverage in the resulting capsules can be tuned by adjusting the concentration of the GO dispersion during the assembly. The capsules retain the approximate shape and size of the erythrocyte template after the latter is totally removed by oxidation with NaOCl in water. The PE/GO capsules maintain their integrity and can be placed or located on other surfaces such as in a device. When the capsules are dried in air, they collapse to form a film that is approximately twice the thickness of the capsule membrane. AFM images in the present study suggest a film thickness of approx. 30 nm for the capsules in the collapsed state implying a thickness of approx. 15 nm for the layers in the collapsed capsule membrane. The polyelectrolytes used in the present study were polyallylamine hydrochloride (PAH and polystyrenesulfonate sodium salt (PSS. Capsules where characterized by transmission electron microscopy (TEM, atomic force microscopy (AFM, dynamic light scattering (DLS and Raman microscopy, the constituent layers by zeta potential and GO by TEM, XRD, and Raman and FTIR spectroscopies.

Epigallocatechin-3-Gallate Protects Erythrocyte Ca2+-ATPase and Na+/K+-ATPase Against Oxidative Induced Damage During Aging in Humans

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Prabhanshu Kumar

2014-10-01

Full Text Available Purpose: The main purpose of this study was to investigate the protective role of epigallocatechin-3-gallate on tertiary butyl hydroperoxide induced oxidative damage in erythrocyte during aging in humans. Methods: Human erythrocyte membrane bound Ca2+-ATPase and Na+/K+-ATPase activities were determined as a function of human age. Protective role of epigallocatechin-3-gallate was evaluated by in vitro experiments by adding epigallocatechin-3-gallate in concentration dependent manner (final concentration range 10-7M to 10-4M to the enzyme assay medium. Oxidative stress was induced in vitro by incubating washed erythrocyte ghosts with tertiary butyl hydroperoxide (10-5 M final concentration. Results: We have reported concentration dependent effect of epigallocatechin-3-gallate on tertiary butyl hydroperoxide induced damage on activities of Ca2+-ATPase and Na+/K+-ATPase during aging in humans. We have detected a significant (p < 0.001 decreased activity of Ca2+-ATPase and Na+/K+ -ATPase as a function of human age. Epigallocatechin-3-gallate protected ATPases against tertiary butyl hydroperoxide induced damage in concentration dependent manner during aging in humans. Conclusion: Epigallocatechin-3-gallate is a powerful antioxidant that is capable of protecting erythrocyte Ca2+-ATPase and Na+/K+ -ATPase against oxidative stress during aging in humans. We may propose hypothesis that a high intake of catechin rich diet may provide some protection against development of aging and age related diseases.

21 CFR 864.6700 - Erythrocyte sedimentation rate test.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Erythrocyte sedimentation rate test. 864.6700 Section 864.6700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6700 Erythrocyte...

Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions.

Science.gov (United States)

Casella, S; Piccione, D; Ielati, S; Bocchino, E G; Piccione, G

2013-06-01

The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3. Copyright © 2012 John Wiley & Sons, Ltd.

Isolation and characterization of cDNA clones for human erythrocyte β-spectrin

International Nuclear Information System (INIS)

Prchal, J.T.; Morley, B.J.; Yoon, S.H.; Coetzer, T.L.; Palek, J.; Conboy, J.G.; Kan, Y.W.

1987-01-01

Spectrin is an important structural component of the membrane skeleton that underlies and supports the erythrocyte plasma membrane. It is composed of nonidentical α (M/sub r/ 240,000) and β (M/sub r/ 220,000) subunits, each of which contains multiple homologous 106-amino acid segments. The authors report here the isolation and characterization of a human erythroid-specific β-spectrin cDNA clone that encodes parts of the β-9 through β-12 repeat segments. This cDNA was used as a hybridization probe to assign the β-spectrin gene to human chromosome 14 and to begin molecular analysis of the gene and its mRNA transcripts. RNA transfer blot analysis showed that the reticulocyte β-spectrin mRNA is 7.8 kilobases in length. Southern blot analysis of genomic DNA revealed the presence of restriction fragment length polymorphisms (RFLPs) within the β-spectrin gene locus. The isolation of human spectrin cDNA probes and the identification of closely linked RFLPs will facilitate analysis of mutant spectrin genes causing congenital hemolytic anemias associated with quantitative and qualitative spectrin abnormalities

Subcutaneous administration of carrier erythrocytes: slow release of entrapped agent

International Nuclear Information System (INIS)

DeLoach, J.R.; Corrier, D.E.

1988-01-01

Carrier erythrocytes administered subcutaneously in mice release encapsulated molecules at the injection site and through cells that escape the injection site. One day postinjection, the efflux of encapsulated [ 14 C]sucrose, [ 3 H]inulin, and 51 Cr-hemoglobin from the injection site was 45, 55, and 65%, respectively. Intact carrier erythrocytes escaped the injection site and entered the blood circulation carrying with them the encapsulated molecules. Most of the encapsulated [ 3 H]inulin that reached whole blood circulated within erythrocytes. Small but measurable numbers of encapsulated molecules were trapped within lymph nodes. Subcutaneous injection of carrier erythrocytes may allow for limited extravascular tissue targeting of drugs

Intraspecific variation in erythrocyte sizes among populations of Hypsiboas cordobas (Anura: Hylidae

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Mariana Baraquet

2013-12-01

Full Text Available We studied the morphology and size of erythrocytes of H. cordobae, and analysed the geographic variation of this character along the distribution of the species, in relation to the latitudinal and altitudinal distances. Erythrocyte shape of the H. cordobae is ellipsoidal and the nuclei are also ellipsoidal and centrally oriented. Erythrocyte and nuclear size showed significant differences among populations, with the highest mean size corresponding to the population of Achiras (low altitude site and the lowest mean size to Los Linderos (high altitude site. There was no significant relationship between the latitude of each population and the both erythrocyte and nuclear size. The altitudinal variation in erythrocyte cell size may be attributable to the surface available for gas exchange; a small erythrocyte offers a possibility of greater rate of exchange than a larger one. Our results are consistent with studies of other amphibians, where intraspecific comparisons of populations at different altitudes show that individuals at higher altitudes are characterized by smaller erythrocytes.

Photoreceptor change and visual outcome after idiopathic epiretinal membrane removal with or without additional internal limiting membrane peeling.

Science.gov (United States)

Ahn, Seong Joon; Ahn, Jeeyun; Woo, Se Joon; Park, Kyu Hyung

2014-01-01

To compare the postoperative photoreceptor status and visual outcome after epiretinal membrane removal with or without additional internal limiting membrane (ILM) peeling. Medical records of 40 eyes from 37 patients undergoing epiretinal membrane removal with residual ILM peeling (additional ILM peeling group) and 69 eyes from 65 patients undergoing epiretinal membrane removal without additional ILM peeling (no additional peeling group) were reviewed. The length of defects in cone outer segment tips, inner segment/outer segment junction, and external limiting membrane line were measured using spectral domain optical coherence tomography images of the fovea before and at 1, 3, 6, and 12 months after the surgery. Cone outer segment tips and inner segment/outer segment junction line defects were most severe at postoperative 1 month and gradually restored at 12 months postoperatively. The cone outer segment tips line defect in the additional ILM peeling group was significantly greater than that in the no additional peeling group at postoperative 1 month (P = 0.006), and best-corrected visual acuity was significantly worse in the former group at the same month (P = 0.001). There was no significant difference in the defect size and best-corrected visual acuity at subsequent visits and recurrence rates between the two groups. Patients who received epiretinal membrane surgery without additional ILM peeling showed better visual and anatomical outcome than those with additional ILM peeling at postoperative 1 month. However, surgical outcomes were comparable between the two groups, thereafter. In terms of visual outcome and photoreceptor integrity, additional ILM peeling may not be an essential procedure.

Interaction of cationic carbosilane dendrimers and their complexes with siRNA with erythrocytes and red blood cell ghosts.

Science.gov (United States)

Wrobel, Dominika; Kolanowska, Katarzyna; Gajek, Arkadiusz; Gomez-Ramirez, Rafael; de la Mata, Javier; Pedziwiatr-Werbicka, Elżbieta; Klajnert, Barbara; Waczulikova, Iveta; Bryszewska, Maria

2014-03-01

We have investigated the interactions between cationic NN16 and BDBR0011 carbosilane dendrimers with red blood cells or their cell membranes. The carbosilane dendrimers used possess 16 cationic functional groups. Both the dendrimers are made of water-stable carbon-silicon bonds, but NN16 possesses some oxygen-silicon bonds that are unstable in water. The nucleic acid used in the experiments was targeted against GAG-1 gene from the human immunodeficiency virus, HIV-1. By binding to the outer leaflet of the membrane, carbosilane dendrimers decreased the fluidity of the hydrophilic part of the membrane but increased the fluidity of the hydrophobic interior. They induced hemolysis, but did not change the morphology of the cells. Increasing concentrations of dendrimers induced erythrocyte aggregation. Binding of short interfering ribonucleic acid (siRNA) to a dendrimer molecule decreased the availability of cationic groups and diminished their cytotoxicity. siRNA-dendrimer complexes changed neither the fluidity of biological membranes nor caused cell hemolysis. Addition of dendriplexes to red blood cell suspension induced echinocyte formation. Copyright © 2013 Elsevier B.V. All rights reserved.

Heterologous desensitization of adenylate cyclase from pigeon erythrocytes under the action of the catalytic subunit of cAMP-dependent protein kinase

International Nuclear Information System (INIS)

Popov, K.M.; Bulargina, T.V.; Severin, E.S.

1985-01-01

Preincubation of the plasma membranes from pigeon erythrocytes with the catalytic subunit of cAMP-dependent protein kinase leads to desensitization of adenylate cyclase of the erythrocytes. The adenylate cyclase activity, measured in the presence of 10 μM isoproterenol and 50 μM GTP-γ-S, is decreased by 40% in 10 min of incubation, while the activity in the presence of 50 μM GTP-γ-S is decreased by 35% in 20 min. The decrease in the adenylate cyclase activity is due to an increase in the lag phase of activation of the enzyme in the presence of a GTP analog stable to hydrolysis and a decrease in the activity in the steady-state phase of activation. Heterologous desensitization of adenylate cyclase under the action of cAMP-dependent protein kinase is coupled with a decrease in the number of β-adrenoreceptors capable of passing into a state of high affinity for antagonists in the absence of guanylic nucleotides. The influence of the catalytic subunit on adenylate cyclase entirely models the process of desensitization of the enzyme absorbed in the influence of isoproterenol or cAMP on erythrocytes

Effect of high linear energy transfer radiation on biological membranes

International Nuclear Information System (INIS)

Choudhary, D.; Srivastava, M.; Kale, R.K.; Sarma, A.

1998-01-01

Cellular membranes are vital elements, and their integrity is extremely essential for the viability of the cells. We studied the effects of high linear energy transfer (LET) radiation on the membranes. Rabbit erythrocytes (1 x 10 7 cells/ml) and microsomes (0.6 mg protein/ml) prepared from liver of rats were irradiated with 7 Li ions of energy 6.42 MeV/u and 16 O ions of energy 4.25 MeV/u having maximum LET values of 354 keV/μm and 1130 keV/μm, respectively. 7 Li- and 16 O-induced microsomal lipid peroxidation was found to increase with fluence. The 16 O ions were more effective than 7 Li ions, which could be due to the denser energy distribution in the track and the yield of free radicals. These findings suggested that the biological membranes could be peroxidized on exposure to high-LET radiation. Inhibition of the lipid peroxidation was observed in the presence of a membrane-active drug, chlorpromazine (CPZ), which could be due to scavenging of free radicals (mainly HO. and ROO.), electron donation, and hydrogen transfer reactions. The 7 Li and 16 O ions also induced hemolysis in erythrocytes. The extent of hemolysis was found to be a function of time and fluence, and showed a characteristic sigmoidal pattern. The 16 O ions were more effective in the lower fluence range than 7 Li ions. These results were compared with lipid peroxidation and hemolysis induced by gamma-radiation. (orig.)

[Modification of the pattern of fatty acids of erythrocytes’ membranes due to the acetone intoxication].

Science.gov (United States)

Momot, T V; Kushnerova, N F; Rakhmanin, Yu A

Results of the study of the impact of acetone intoxication on the fatty acids pattern of the general lipids of erythrocytes’ membranes in rats are presented. The inhalation exposure of acetone was carried out in the inoculation chamber with the volume of 100 liters. The chamber was designed for the type of B.A. Kurlyandsky with self-contained system of purification and air regeneration and specified parameters of temperature (20-22С) and air humidity. The flow rate of the air and aerosolized acetone passed through the chamber accounted of 10 liters/min. Concentration of acetone in the chamber was sustained at the level of 206 ± 3,9 mg/m that corresponds to maximum permissible concentration for acetone vapor in the air of a working area. The time of exposure was 6 hours per day for 3 weeks in a monotonous mode, excluding weekend, and was based upon specific parameters of environment simulation in industry. The acetone impact was shown to be accompanied by the gain in the quantity of all kinds of saturated fatty acids and the fall of unsaturated fatty acids in general lipids of erythrocytes ’ membranes in rats and in the structure ofphospholipid fractions. In the content of phosphatydilcholine and phosphatydilethanolamine, as a basic structural phospholipids of biological membranes, there was noted the increase in palmitic and stearic acids. In the range offatty acids of the n-6 family the amount of linoleic and arachidonic acids decreased. In the array of fatty acids of the n-3 family the content of linolenic, eicosapentaenoic and docosahexaenoic acids (n-3 family) declined. Redistribution of fatty acids in the erythrocytes membrane towards to such alteration in quantity as the increasing of saturation and decreasing of the unsaturated fatty acids supposes the change of its physical and chemical properties, permeability, lability and complexity of passing erythrocyte via microcircular channels.

Internal hydration of a metal-transporting ATPase is controlled by membrane lateral pressure

Energy Technology Data Exchange (ETDEWEB)

Fahmy, Karim [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Fischermeier, E. [Technische Univ. Dresden (Germany); Pospisil, P. [A.S.C. R., Prague (Czech Republic). J. Heyrovsky Inst. Physical Chemistry; Solioz, M. [Bern Univ. (Switzerland); Sayed, A.; Hof, M.

2017-07-01

The active transport of ions across biological mem branes requires their hydration shell to interact with the interior of membrane proteins. However, the influence of the external lipid phase on internal dielectric dynamics is hard to access by experiment. Using the octahelical transmembrane architecture of the copper-transporting P{sub 1B}-type ATPase from Legionella pneumophila (LpCopA) as a model structure, we have established the site-specific labeling of internal cysteines with a polarity-sensitive fluorophore. This enabled dipolar relaxation studies in a solubilized form of the protein and in its lipid-embedded state in nano-discs (NDs). Time-dependent fluorescence shifts revealed the site-specific hydration and dipole mobility around the conserved ion-binding motif. The spatial distribution of both features is shaped significantly and independently of each other by membrane lateral pressure.

Internal hydration of a metal-transporting ATPase is controlled by membrane lateral pressure

International Nuclear Information System (INIS)

Fahmy, Karim; Pospisil, P.; Sayed, A.; Hof, M.

2017-01-01

The active transport of ions across biological mem branes requires their hydration shell to interact with the interior of membrane proteins. However, the influence of the external lipid phase on internal dielectric dynamics is hard to access by experiment. Using the octahelical transmembrane architecture of the copper-transporting P_1_B-type ATPase from Legionella pneumophila (LpCopA) as a model structure, we have established the site-specific labeling of internal cysteines with a polarity-sensitive fluorophore. This enabled dipolar relaxation studies in a solubilized form of the protein and in its lipid-embedded state in nano-discs (NDs). Time-dependent fluorescence shifts revealed the site-specific hydration and dipole mobility around the conserved ion-binding motif. The spatial distribution of both features is shaped significantly and independently of each other by membrane lateral pressure.

Isolation and Characterization of Erythrocyte and Parasite Membranes from Rhesus Red Cells Infected with P. knowlesi.

Science.gov (United States)

1981-06-01

initiated experiments to separate and isolate the vacuolar membrane and the parasite plasma menbrane . For this, the surfaces of intact schizonts...controlled nitrogen decompression (1) is surrounded by two membranes, its own plasma membrane and the membrane of the parasitophorous vacuole. We have

Cryo scanning electron microscopy of Plasmodium falciparum-infected erythrocytes

DEFF Research Database (Denmark)

Hempel, Casper

2017-01-01

Plasmodium falciparum invades erythrocytes as an essential part of their life cycle. While living inside erythrocytes, the parasite remodels the cell's intracellular organization as well as its outer surface. Late trophozoite-stage parasites and schizonts introduce numerous small protrusions...

Plasmodium falciparum-infected erythrocytes do not adhere well to C32 melanoma cells or CD36 unless rosettes with uninfected erythrocytes are first disrupted.

OpenAIRE

Handunnetti, S M; Hasler, T H; Howard, R J

1992-01-01

Plasmodium falciparum malaria parasites modify the human erythrocytes in which they grow so that some parasitized erythrocytes (PE) can cytoadhere (C+) to host vascular endothelial cells or adhere in rosettes (R+) to uninfected erythrocytes. These C+ and R+ adherence properties of PE appear to mediate much of the pathogenesis of severe malaria infections, in part by blocking blood flow in microvessels. From one parasite strain, PE were selected in vitro for C+ R+ or C+ R- adherence properties...

Delayed effects of radiation on enzymes in erythrocytes

International Nuclear Information System (INIS)

Li Jinying; Zhang Weiping; Liu Benti

1998-01-01

Objective: To study the delayed effects of radiation on the enzymes in erythrocytes. Methods: The activity of 8 enzymes, related glycolysis, hexose monophosphate shunt, nucleotide metabolism, redox reaction and esterase in erythrocytes of five patients with bone marrow form of acute radiation sickness (ARS) were assayed at 1,2,3 and 6 years after exposure to 60 Co radiation. Results: The decreased activities of glucose-6-phosphate dehydrogenase (G6PD), pyruvate kinase (PK), NADH-methemoglobin reductase (MR) during the stage of crisis and of acetylcholinesterase (ACE) during the stage of convalescence were recovered to varying extent, whereas the lowered activities of the first three enzymes in some cases remained unchanged. There was no correlation between the enzyme activity and the radiation dose as well as the age of the patients. Conclusion: It is demonstrated that the delayed effects of radiation damage to erythrocyte enzymes are most significant in PK of glycolysis, G6PD of hexose monophosphate shunt and MR of redox reaction. It is suggested that the genes related to the synthesis of erythrocyte enzymes may be damaged by radiation

Analyzing Plasmodium falciparum erythrocyte membrane protein 1 gene expression by a next generation sequencing based method

DEFF Research Database (Denmark)

Jespersen, Jakob S.; Petersen, Bent; Seguin-Orlando, Andaine

2013-01-01

at identifying PfEMP1 features associated with high virulence. Here we present the first effective method for sequence analysis of var genes expressed in field samples: a sequential PCR and next generation sequencing based technique applied on expressed var sequence tags and subsequently on long range PCR......, encoded by ~60 highly variable 'var' genes per haploid genome. PfEMP1 is exported to the surface of infected erythrocytes and is thought to be fundamental to immune evasion by adhesion to host and parasite factors. The highly variable nature has constituted a roadblock in var expression studies aimed...

Adenosine deaminase activity of erythrocytes in hyperuricemia

International Nuclear Information System (INIS)

Krueger, W.; Richter, V.; Beenken, O.; Weinhold, D.; Hirschberg, K.; Rotzsch, W.; Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung)

1982-01-01

Erythrocytic adenosine deaminase (ADA) activity was determined in 55 patients with primary hyperuricemia and in 37 healthy control persons. Unlike the controls, the ADA activity in the patient group showed a two-peak response. Hyperuricemia patients with high ADA activity also exhibited increased uric acid excretion and elevated 15 N incorporation into uric acid. High activity values of erythrocytic ADA can be interpreted as an uric acid overproduction, giving hints for a therapeutic plan. (author)

Ninth International Workshop on Plant Membrane Biology

Energy Technology Data Exchange (ETDEWEB)

1993-12-31

This report is a compilation of abstracts from papers which were discussed at a workshop on plant membrane biology. Topics include: plasma membrane ATP-ases; plant-environment interactions, membrane receptors; signal transduction; ion channel physiology; biophysics and molecular biology; vaculor H+ pumps; sugar carriers; membrane transport; and cellular structure and function.

Eccentric Macular Hole after Pars Plana Vitrectomy for Epiretinal Membrane Without Internal Limiting Membrane Peeling: A Case Report.

Science.gov (United States)

Garnavou-Xirou, Christina; Xirou, Tina; Kabanarou, Stamatina; Gkizis, Ilias; Velissaris, Stavros; Chatziralli, Irini

2017-12-01

Postoperative eccentric macular hole formation is an uncommon complication after pars plana vitrectomy (PPV) without internal limiting membrane (ILM) peeling for the treatment of epiretinal membrane (ERM). We present a case of eccentric macular hole formation after PPV for ERM without ILM peeling. A 68-year-old male patient presented with ERM and visual acuity of 6/24 in his left eye. He underwent 23-gauge PPV without ILM peeling for treatment of ERM. One week postoperatively the retina was attached and the epiretinal membrane was successfully removed, while visual acuity was 6/9. One month after PPV, a single eccentric retinal hole below the macula was detected using fundoscopy and subsequently confirmed by optical coherence tomography. At this time the visual acuity was 6/9 and the patient reported no symptoms. No further intervention was attempted and at the 9-month follow-up, the visual acuity and the size of the eccentric macular hole remained stable. Eccentric macular holes can be developed after PPV even without ILM peeling and are usually managed conservatively by observation.

Physiological variations in levels of 2,3-diphosphoglycerate in horse erythrocytes.

Science.gov (United States)

Lewis, I M; McLan, J G

1975-03-01

The levels of 2,3-diphosphoglycerate (2,3-DPG), which affects the transport of oxygen by haemoglobin, were examined in horse blood. Resting levels of erythrocyte 2,3-DPG were established in thoroughbred horses, and levels of 2,3-DPG together with haemoglobin levels, were examined in a variety of conditions. A negative correlation was observed between erythrocyte 2,3-DPG and haemoglobin levels. Mares had higher erythrocyte 2,3-DPG levels was observed during training, and this variation may have a significant effect on haemoglobin oxygen transport. Erythrocyte 2,3-DPG levels were not affected by age or exercise.

Ultraviolet- and sunlight-induced lipid peroxidation in liposomal membrane

International Nuclear Information System (INIS)

Mandal, T.K.; Chatterjee, S.N.

1980-01-01

Ultraviolet radiation and sunlight caused lipid peroxidation in the liposomal membrane (as detected by measurement of the oxidation index, A 233 /A 215 , and the amount of malondialdehyde formed) and made the membrane leaky (as revealed by the release of the trapped chromate anions). The oxidation index and the formation of malondialdehyde increased linearly with increasing dose of radiation and depended significantly on the dose rate. The effects were smaller in liposomes derived from Vibrio cholerae phospholipid than in those derived from egg lecithin. The effects of the radiation dose and dose rate on hemolysis and peroxidation (MDA formation) of the erythrocyte membrane followed a similar pattern. A direct correlation between the percentage leakage of chromate (Y) and the oxidation index (X) of the liposomal system was obtained as Y = 236.5 x X

Retinal thinning after internal limiting membrane peeling for idiopathic macular hole.

Science.gov (United States)

Imamura, Yutaka; Ishida, Masahiro

2018-03-01

To determine the changes in retinal thickness and whether they correlate with the size of the macular hole (MH) after vitrectomy with internal limiting membrane peeling. Retrospective, interventional case series METHODS: Consecutive patients with an MH and undergoing pars plana vitrectomy with internal limiting membrane peeling were studied. The retinal thicknesses in the inner 4 sectors as defined by the Early Treatment of Diabetic Retinopathy Study were measured using spectral-domain optical coherence tomography (SD-OCT) before and at 2 weeks and 1, 3, 6, and 12 months after the surgery. The basal and minimum diameters of the MHs were measured. The correlations between the retinal thicknesses and the size of the MH were determined. Thirty-three eyes of 32 consecutive patients (18 women; mean age, 64.2 ± 8.8 years) with an MH were studied. Thirteen eyes had a stage-2 MH; 12 eyes, a stage-3 MH; and 8 eyes, a stage-4 MH. The mean retinal thickness in the temporal sector was 362.8 ± 29.9 µm preoperatively, 337.9 ± 20.6 µm at 2 weeks postoperatively, and 307.6 ± 20.2 µm at 12 months postoperatively (P peeling.

Staphylococcus aureus α-toxin-dependent induction of host cell death by membrane-derived vesicles.

Directory of Open Access Journals (Sweden)

Bernard Thay

Full Text Available Staphylococcus aureus causes a wide spectrum of infections in humans, ranging from superficial cutaneous infections, infections in the circum-oral region, to life-threatening bacteremia. It was recently demonstrated that Gram-positive organisms such as S. aureus liberate membrane-derived vesicles (MVs, which analogously to outer membrane vesicles (OMVs of Gram-negative bacteria can play a role in delivering virulence factors to host cells. In the present study we have shown that cholesterol-dependent fusion of S. aureus MVs with the plasma membrane represents a route for delivery of a key virulence factor, α-toxin (α-hemolysin; Hla to human cells. Most S. aureus strains produce this 33-kDa pore-forming protein, which can lyse a wide range of human cells, and induce apoptosis in T-lymphocytes. Our results revealed a tight association of biologically active α-toxin with membrane-derived vesicles isolated from S. aureus strain 8325-4. Concomitantly, α-toxin contributed to HeLa cell cytotoxicity of MVs, and was the main vesicle-associated protein responsible for erythrocyte lysis. In contrast, MVs obtained from an isogenic hla mutant were significantly attenuated with regards to both causing lysis of erythrocytes and death of HeLa cells. This is to our knowledge the first recognition of an S. aureus MV-associated factor contributing to host cell cytotoxicity.

Desickling of Sickle Cell Erythrocytes by Pulsed RF Fields.

Science.gov (United States)

1986-09-16

spectrophotometery. Field induced menbrane potential which causes the L partyl breakdown of the memrbrane and the formation of pores was calculated... plasma . Fig.5 shows the photographs of sickled and desickled SS erythrocytes which are suspended in Hank’s solution. As shown, desickled erythrocytes

Flow and fouling in membrane filters: Effects of membrane morphology

Science.gov (United States)

Sanaei, Pejman; Cummings, Linda J.

2015-11-01

Membrane filters are widely-used in microfiltration applications. Many types of filter membranes are produced commercially, for different filtration applications, but broadly speaking the requirements are to achieve fine control of separation, with low power consumption. The answer to this problem might seem obvious: select the membrane with the largest pore size and void fraction consistent with the separation requirements. However, membrane fouling (an inevitable consequence of successful filtration) is a complicated process, which depends on many parameters other than membrane pore size and void fraction; and which itself greatly affects the filtration process and membrane functionality. In this work we formulate mathematical models that can (i) account for the membrane internal morphology (internal structure, pore size & shape, etc.); (ii) fouling of membranes with specific morphology; and (iii) make some predictions as to what type of membrane morphology might offer optimum filtration performance.

Oxidative stress and damage to erythrocytes in patients with chronic obstructive pulmonary disease--changes in ATPase and acetylcholinesterase activity.

Science.gov (United States)

Bukowska, Bożena; Sicińska, Paulina; Pająk, Aneta; Koceva-Chyla, Aneta; Pietras, Tadeusz; Pszczółkowska, Anna; Górski, Paweł; Koter-Michalak, Maria

2015-12-01

The study indicates, for the first time, the changes in both ATPase and AChE activities in the membrane of red blood cells of patients diagnosed with COPD. Chronic obstructive pulmonary disease (COPD) is one of the most common and severe lung disorders. We examined the impact of COPD on redox balance and properties of the membrane of red blood cells. The study involved 30 patients with COPD and 18 healthy subjects. An increase in lipid peroxidation products and a decrease in the content of -SH groups in the membrane of red blood cells in patients with COPD were observed. Moreover, an increase in the activity of glutathione peroxidase and a decrease in superoxide dismutase, but not in catalase activity, were found as well. Significant changes in activities of erythrocyte membrane enzymes in COPD patients were also evident demonstrated by a considerably lowered ATPase activity and elevated AChE activity. Changes in the structure and function of red blood cells observed in COPD patients, together with changes in the activity of the key membrane enzymes (ATPases and AChE), can result from the imbalance of redox status of these cells due to extensive oxidative stress induced by COPD disease.

Life cycle-dependent cytoskeletal modifications in Plasmodium falciparum infected erythrocytes.

Directory of Open Access Journals (Sweden)

Hui Shi

Full Text Available Plasmodium falciparum infection of human erythrocytes is known to result in the modification of the host cell cytoskeleton by parasite-coded proteins. However, such modifications and corresponding implications in malaria pathogenesis have not been fully explored. Here, we probed the gradual modification of infected erythrocyte cytoskeleton with advancing stages of infection using atomic force microscopy (AFM. We reported a novel strategy to derive accurate and quantitative information on the knob structures and their connections with the spectrin network by performing AFM-based imaging analysis of the cytoplasmic surface of infected erythrocytes. Significant changes on the red cell cytoskeleton were observed from the expansion of spectrin network mesh size, extension of spectrin tetramers and the decrease of spectrin abundance with advancing stages of infection. The spectrin network appeared to aggregate around knobs but also appeared sparser at non-knob areas as the parasite matured. This dramatic modification of the erythrocyte skeleton during the advancing stage of malaria infection could contribute to the loss of deformability of the infected erythrocyte.