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Flow cytometry (FC) analysis of erythrocyte shape and related biomechanical properties, such as osmotic fragility, have not moved from a research tool to regular clinical testing. The main reason is existing evidence that various pre-analytical factors influence the mathematical interpretation of the data obtained. With an aim to contribute to the standardization and broaden the use of FC for human erythrocyte shape assessment, freshly prepared peripheral blood erythrocytes isolated from healthy donors were incubated in iso and hypo-osmotic solutions (pure saline, saline with potassium and calcium, and phosphate buffered saline) and examined by FC using values of forward scatter (FSC) and side scatter (SSC). Kurtosis, skewness, Pearson's second skewness coefficient of dissymmetry (PCD), and spherical index, calculated from FSC distributions, were used for the erythrocyte shape evaluation. In all isotonic media FSC distribution and FSC-based morphology parameters showed huge inter-individual and inter-medium variation. With decreasing osmolality, in all media and samples, the size of the erythrocytes increased, and swelling index and kurtosis decreased. However, changes in skewness and PCD were influenced by the medium used and the sample tested. Compared to FSC, SSC signal in isotonic and its change in hypotonic media showed lower inter-individual variation and was not influenced by the type of medium. We propose a spherical index and kurtosis as FSC-based indicators of erythrocyte shape. As more resistant to the influence of the preanalytical treatment, SSC data appeared to be unfairly neglected for the assessment of erythrocyte shape, in comparison to the usually employed FSC data.

A biophysical approach was demonstrated for determining the dynamics of change in the zinc ion pool in human erythrocytes in the range from 1–1000 nM using a FluoZin-3 fluorescent probe. This method can be used in biomedical research and serve as the basis for developing diagnostic methods or predicting the course of diseases associated with a failure in zinc metabolism.

The Red-emitting nitrogen-doped carbon dots (N-CDs) are synthesized using o-phenylenediamine by a one-step method, and can serve as a fluorescent probe for "turn off" detection of hematin in human red cells. The red-emitting N-CDs can be obtained only in acidic conditions and the emission of the red-emitting N-CDs is pH-dependent, indicating proton-controlled synthesis and emission. The red-emitting N-CDs are 2.7 nm in mean size and have a uniform dispersion and exhibit a high quantum yield (12.8%) and great optical properties. The developed sensing system for hematin displays a linear response from 0.4 to 32 μM with a detection limit of 0.18 μM. Importantly, this fluorescent probe demonstrates a good potential practicability for the quantitative detection of hematin in complex matrixes. Graphical abstract ᅟ.

Nitrite is present as a noxious contaminant in drinking water and causes oxidative damage in various tissues of humans and animals. It is a well-known methemoglobin-forming agent that has been shown to damage blood cells. The protective effect of taurine, a semi-essential sulfur-containing amino acid, was studied on sodium nitrite (NaNO2)-induced oxidative damage in human erythrocytes. Erythrocytes were incubated with NaNO2, in the presence and absence of taurine, and changes in oxidative stress parameters determined. Pretreatment with taurine significantly ameliorated NaNO2-induced oxidative damage to lipids, proteins, and plasma membrane. It also reduced the NaNO2-induced increase in methemoglobin levels and ROS production. Taurine improved the antioxidant capacity of cells, restored the alterations in the activities of various metabolic enzymes, and prevented morphological changes in erythrocytes. Thus, taurine can be potentially used as a protective agent against the damaging effects of nitrite.

Purpose of Review Human erythrocytes are responsible for oxygen delivery in the body. Erythrocytes are a product of terminal differentiated erythroid cells that accumulate hemoglobin and exclude nuclei. The long-held conventional wisdom has been that mature erythrocytes lack any genetic materials. Contrary to this view, accumulating evidence from multiple groups indicates that erythrocytes contain abundant and diverse RNA species. These newly discovered genetic materials suddenly open up opportunities to re-examine many diseases affecting erythrocytes.

Membranolytic anticancer peptides represent a potential strategy in the fight against cancer. However, our understanding of the underlying structure-activity relationships and the mechanisms driving their cell selectivity is still limited. We developed a computational approach as a step towards the rational design of potent and selective anticancer peptides. This machine learning model distinguishes between peptides with and without anticancer activity. This classifier was experimentally validated by synthesizing and testing a selection of 12 computationally generated peptides. In total, 83% of these predictions were correct. We then utilized an evolutionary molecular design algorithm to improve the peptide selectivity for cancer cells. This simulated molecular evolution process led to a five-fold selectivity increase with regard to human dermal microvascular endothelial cells and more than ten-fold improvement towards human erythrocytes. The results of the present study advocate for the applicability of machine learning models and evolutionary algorithms to design and optimize novel synthetic anticancer peptides with reduced hemolytic liability and increased cell-type selectivity., Scientific Reports, 9, ISSN:2045-2322

Nuclear magnetic resonance (NMR) magnetization-transfer (MT) experiments provide a convenient tool for studying rapid sub-second membrane-transport processes in situ in metabolically active cells. These experiments are used with membrane-permeable substances when separate (resolved) NMR signals are observed from their populations inside and outside the cells. Here, we provide a description of the theory and practice of the most common NMR MT experiments that have been used to study membrane-transport processes in human erythrocytes (red blood cells; RBCs). The procedures, involved in the analysis of the experimental data for defining mechanisms of transport, and for estimating values of kinetic parameters in the corresponding mathematical models, are given special attention.

Wilson’s disease is a disease of abnormal copper metabolism in which free serum copper level is raised. The objective of the study was to determine, whether in Wilson disease, l-cysteine/l-cystine influx into RBC was decreased or not and the specific amino acid transporter affected by copper in normal human RBC. For l-cysteine/l-cystine influx, ten untreated cases, ten treated cases and ten age and sex matched healthy controls were recruited. To study the effect of copper on l-cysteine/l-cystine influx in RBC, 15 healthy subjects were selected. RBC GSH and l-cysteine/l-cystine influx were estimated by Beautler’s and Yildiz’s method respectively. In untreated cases, l-cysteine/l-cystine influx and erythrocyte GSH level were decreased showing that elevated level of free copper in serum or media decreased l-cysteine/l-cystine influx in human RBC. Copper treatment inhibited L amino acid transporter in normal RBC specifically.

Based on confocal fluorescence and bright field video microscopy, we present detailed observations on the processes of invasion and egress of erythrocytes by the apicomplexan parasite Babesia divergens. Time-lapse images reveal numerous unexpected findings associated with the dynamics of B. divergens and its ability to manipulate the erythrocyte during both processes in its asexual cycle under in vitro conditions. Despite the speed at which these processes occur and the small size of the parasite, we capture infective merozoites moving vigorously and causing striking deformations in the erythrocyte's plasma membrane during an active invasion. We also observed intraerythrocytic dynamic stages as paired pyriforms, double paired pyriforms, tetrads, unattached pyriform sister cells and multiple parasite stages resulting in the release of large numbers of merozoites over a short period. Of considerable interest is that time-lapse images reveal a novel mechanism of egress used by B. divergens to exit the human erythrocyte. The release occurs when B. divergens parasites establish contacts with the plasma membrane of the erythrocyte from within, before exiting the cell. Visualization and analysis of the images enabled us to obtain useful information and broaden our knowledge of complex and crucial events involved with parasitisation of human erythrocytes by B. divergens. This work was funded by grants from Ministerio de Economía y Competitividad from Spain (AGL2010-21774, AGL2014-56193 R to EM and LMG). E. Sevilla was awarded a research fellowship from Plan Estatal de Investigación Científica y Técnica y de Innovación, Ministerio de Economía y Competitividad, Spain. Sí

Biological model of hypoxia can be used for the diagnosis of functional changes in human erythrocytes under the effect of the hypoxic factor. The use of this model together with modern methods of scanning probe microscopy for evaluation of the severity of pulmonological disease in senile patients will help to predict treatment efficiency and outcome.

The effects of doxycycline on the morphology and function of donor erythrocytes were studied by scanning electron microscopy. The antibiotic in concentrations of 7.8 × 10(-5) and 7.8 × 10(-6) mol/liter induced heterogeneous changes in the surface architectonics in the erythrocyte population. These data indicated stimulation of erythrocyte "aging" under the effect of doxycycline.

We present the results of studies on the effect of optical radiation on thermal denaturing of oxyhemoglobin and hemolysis of human erythrocytes. We have established that low-intensity laser radiation promotes decreased structural and conformational changes and stabilizes the oxyhemoglobin molecules and erythrocytes against thermal denaturing.

Previous studies have shown that A. lumbricoides extracts capture sialic acid (SA) from human red blood cells (RBC). The aim of this work was to study hemorheological alterations in vitro caused by parasite larvae. The biorheological action of three larva concentrates of first and second larval stage on group O erythrocytes was analyzed by incubating the erythrocyte packed together with an equal volume of larvae (treated RBC) and PBS (control RBC). Distribution and parameters of aggregation (digital image analysis), aggregation kinetics (erythroaggregameter), and viscoelasticity (erythrodeformeter) were measured. The digital image analysis showed that all the larvae diminished the isolated cells percentage and increased the size of the formed aggregates. The aggregate formation velocity was lower in the treated than in the control. The deformability index (ID) values of treated RBC did not present variations with respect to those of the control, but a decrease in the erythrocyte elastic modulus (μ(m)) and membrane surface viscosity (η(m)) values was observed, indicating that the larvae not only induced a diminution in the membrane surface viscosity of RBC but also altered the dynamic viscoelasticity of the membrane. Experiments carried out in vitro support the conclusion that the contact between larvae and RBC produces hemorheological alterations.

The action of glucose as an osmolyte in relation to blood cells is not well-characterized in the literature. This study aimed to study the influence of glucose concentration on the stability of red blood cells. The stability of erythrocytes was evaluated by the half-transition point obtained from the curves of lysis induced by glucose in the absence of salt or by increase in medium hypotonicity in the absence and the presence of different concentrations of glucose. In the presence of 0.9 g/dl NaCl, there was no hemolysis with increasing concentration of glucose from 0 to 10 g/dl. In the absence of NaCl, the dependence of hemolysis with the 0-10 g/dl glucose was described by a decreasing sigmoid, with fully lysed and fully protected cells being encountered in the presence of 0-2 and 4-10 g/dl glucose, respectively. The possible origin of such stabilization effect is discussed with base of what is known about osmostabilization of biological complexes and about the influence of glucose on the rheological properties of erythrocytes.

One new acetylated flavonoid, kaempferide-7-O-(4″-O-acetyl)-α-L-rhamnoside, and six known flavonoids were isolated from the EtOAc fraction of the leaves of Actinidia kolomikta (Rupr. et Maxim.) Planch. The chemical structures of the isolated compounds were established by application of chemical and spectroscopic analysis. The new acetylated flavonoid was screened for its protective effect on human erythrocytes against AAPH-induced hemolysis, and it can slow the hemolysis induced by AAPH.

Study was focused to effectively suppress the agglutinability of human A and B type erythrocyte by concerted chemical oxidation approach. Consequently some major bio-physiological consequences of human erythrocytes were analyzed.Concerted chemical oxidation of human A and B type erythrocyte were done by potassium permanganate (KMnO(4)) in presence of ethylene diamine tetra-acetic acid (EDTA). All the chemical reactions were carried out at 37°C temperature and pH 7.4 in phosphate buffer. Finally, suppression of agglutinability were determined by using anti-A and anti-B antisera.A marked suppression in agglutinability was observed after chemical treatment on human A and B type erythrocytes in vitro. Effective suppression of agglutinability was observed in 0.57 mM concentration of KMnO(4) in presence of 0.9 mM EDTA at optimum condition.Results showed that KMnO(4)-EDTA concerted action is feasible. The future work is directed towards the universal human erythrocytes preparation from A and B type human erythrocytes.

Glycated hemoglobin A1c (HbA1c) concentration in blood is an index of the glycemic control widely used in diabetology. The aim of the work was to validate two mathematical models of HbA1c formation (assuming irreversible or reversible glycation, respectively) and select a model, which was able to predict changes of HbA1c concentration in response to varying glycemia courses with higher accuracy. The experimental procedure applied consisted of an original combination of: in vivo continuous glucose concentration monitoring, long-term in vitro culturing of the human erythrocytes and mathematical modeling of HbA1c formation in vivo and in vitro with HbA1c values scaled according to the most specific analytical methods. Sixteen experiments were conducted in vitro using blood samples collected from healthy volunteer and stable type 1 diabetic patients whose glycemia was estimated beforehand based on long-term monitoring. The mean absolute difference of the measured and predicted HbA1c concentrations for the in vitro experiments were equal to 0.64 +/- 0.29% and 1.42 +/- 0.16% (p = 0.0007) for irreversible and for reversible model, respectively, meaning that the irreversible model was able to predict the glycation kinetics with a higher accuracy. This model was also more sensitive to a deviation of the erythrocytes life span.

Traditional fecal erythrocyte detection is performed via a manual operation that is unsuitable because it depends significantly on the expertise of individual inspectors. To recognize human erythrocytes automatically and precisely, automatic segmentation is very important for extraction of characteristics. In addition, multiple recognition algorithms are also essential. This paper proposes an algorithm based on morphological segmentation and a fuzzy neural network. The morphological segmentation process comprises three operational steps: top-hat transformation, Otsu's method, and image binarization. Following initial screening by area and circularity, fuzzy c-means clustering and the neural network algorithms are used for secondary screening. Subsequently, the erythrocytes are screened by combining the results of five images obtained at different focal lengths. Experimental results show that even when the illumination, noise pollution, and position of the erythrocytes are different, they are all segmented and labeled accurately by the proposed method. Thus, the proposed method is robust even in images with significant amounts of noise.

Lipid peroxide (LPO) plays pivotal roles in the process and development of many diseases. In this work, we studied the inhibitory effect of probimane (Pro), a Chinese anticancer agent, on erythrocyte LPO and the interaction of Pro with sialic acids (sia). Malondialdehyde (MDA) of erythrocytes activated by hydrogen peroxide was measured. Pro was found to inhibit the product of LPO induced by hydrogen peroxide in a non-enzyme system of both rabbit and human erythrocytes in the absence of doxorubicin. Sia were found to enhance LPO production and the activity of N-glycolylneuraminic acid (NeuGc) was about 5 times higher than that of N-acetylneuraminic acid (5AcNeu) at equivalent concentrations. Pro inhibited the increased LPO production induced by sia and the activity of Pro against LPO with 5AcNeu was almost twofold higher than that of Pro alone. It suggests that Pro be an inhibitor of LPO (free radicals) and as a functional modulator of sia in body.

To maintain a constant supply of “universal blood type”, or group O red blood cells, has benefit in specialized transfusion condition. In this study, α-galactosidase cDNA was cloned from Catimor coffee bean grown in Hainan island, China, by the RT-PCR method. We have constructed a vector for α-galactosidase cDNA expression and transferred α-galactosidase cDNA into Pichia pastoris GS115 cells by electroporation. The recombinant α-galactosidase (r-α-GalE) was purified by cation ion exchange chromatography. After studying the biochemical characters of r-α-GalE, we have succeeded in converting human erythrocytes from group B to group O. The animal experiment showed that transfusion of enzymetically converted group O red blood cells (ECORBC) was perfectly safe.

We briefly review our results of studies into the internal dynamics of proteins of isolated human erythrocyte membranes both in the native state and under the action of factors of a physical and chemical nature (temperature, ionic strength, alcohols, detergents, adhesion) at room temperature by the tryptophan phosphorescence method.

The magnetic behaviour of erythrocytes from patients suffering from beta thalassemia major was investigated. All samples exhibited diamagnetic behaviour. Measurements were made before and after blood transfusion treatment. We suggest that the amount of blood given to the patient should be controlled in a way that the diamagnetic susceptibility after blood transfusion should be equal to that for the normal erythrocytes. In this way a specific range of haemoglobin level (Hgb) should be maintained when the patient is subjected to long-term hypertransfusional treatment.

Thirty-three species of marine algae belonging to Rhodophyta, Phaeophyta and Chlorophyta from the Fujian coast were examined for agglutinins with different animal and human erythrocytes. Protein extracts from 26 species were active against at least one type of the erythrocytes tested. There were 3 species (Grateloupia imbricata, Ishige foliacea andEntermorpha prolifera) whose extracts could agglutimate all the erythrocytes used. The lowest protein concentration required to produce erythrocyte agglutination varied remarkably, from 3.1 μg/ml to 500 μg/ml. The strongest activity was found in the agglutination of rabbit erythrocytes byGloiopeltis furcata extract. Inhibition assays performed with nine mono- and bisaccharides indicated that agglutinations of rabbit erythrocytes by extracts of 7 species were inhibited by one or more types of the sugars assayed. The agglutinating activity shown by extracts of most species was not affected when the test solution was heated to 90°C, but was lost at 95°C–100°C. A few extracts lost their activity at 60°C, 65°C and 75°C, respectively.

We have investigated the presence of total, free, protein-bound and peptide-bound hydroxyproline (Hyp) in the erythrocytes of different mammals namely, camel, bovine, sheep, human, rabbit and rat. Sheep erythrocytes had the highest concentration of free Hyp, followed by camel, bovine, rat, human and rabbit. The concentration of peptide-bound Hyp was the highest in camel erythrocytes followed by bovine, sheep (p

To add an additional aspect to the process of recognition and removal of senescent human erythrocytes from the circulation, the binding of wheat germ agglutinin (WGA) to separated young, old and sialidase-treated human erythrocytes is evaluated with the immune-electron microscopical method. WGA/gold conjugate binding to old erythrocytes was lower (27%) than to young erythrocytes and even lower following treatment with sialidase (82%), exhibiting a clustered, non-continuous labeling pattern in all three erythrocyte populations, thus showing a possible redistribution of WGA binding sites. The decrease in bound WGA/gold particles correlates well with the previously reported decrease in surface sialic acid on old erythrocytes. The binding of WGA/gold are indicative of the changes occurring on erythrocyte membrane surfaces when interacting with different agglutinins.

A novel approach based on atomic force microscopy (AFM) for exploring the elastic properties of the membrane-skeleton complex in living cells is presented. Three major elements constitute the basis for the proposed method: (a) Pulling the cell membrane by increasing the adhesion of the tip to the cell surface provided by the appropriate tip modification; (b) Measuring force-distance curves with the emphasis on the selection of the appropriate withdraw regions for analysis; and (c) Fitting of the theoretical model based on the bending deformation of an elastic plate to the experimental curve in the withdraw region, prior to the detachment point of the tip from the cell membrane. This approach, applied to human erythrocytes, suggests a complementary technique to the commonly used indentation method. The presented method enables us to avoid certain important problems relating to the measurements of elastic characteristics of biological objects by the indentation technique. Firstly, in the range of the pulling technique, it is not necessary to define a “point of contact”. A spurious definition of this point can produce significant errors in the estimation of elastic constants. Secondly, the problem of interference with the substrate is eliminated in the AFM pulling technique. The last feature is important when probing the elastic properties of thin soft samples like a thin flat cells or protein layers.

The light and photodynamic actions on acetylcholinesterase activity from human erythrocytes were studied. After light irradiation (670 nm, semiconducting low power laser) the maximum reaction rate increased from 13.3 to 14.8 mumol per ml packed cells per min for an energy dose 9 J, and above that dose it decreased (10.8 mumol per ml packed cells per min for an energy dose of 15 J). The Michaelis-Menten constant changed in the opposite direction. After irradiation of erythrocyte suspension in the presence of zinc phthalocyanine the reaction rate increased, reaching the maximum for energy dose of 0.75 J (16.85 in comparison to the control value of 14.7 mumol per ml packed cells per min. Similarly, the Michaelis-Menten constant decreased reaching a minimum for an energy dose of 0.75 J (0.04 mM compared to 0.07 mM for control). Incubation of erythrocytes with the dye in the dark increased the reaction rate from 13.3 to 14.7 mumol per ml packed cells per min. Neither the incubation in the dark nor irradiation with laser light caused changes of enzyme activity in the presence of chloroaluminium or metal-free phthalocyanine.

Although extensive studies have been performed on human erythrocytes, there is a shortage of information on marsupial erythrocytes. Studies on haematology and biochemistry are useful in the ecomanagement of these animals especially those in wildlife parks and zoos. The present review summarises our findings from ∼30 species of marsupials. As marsupials show great diversity in physical and behavioural characteristics, it is not surprising that examination of their red blood cells reveals variation in the biochemical features. Many variations in red cell biochemistry appear to be species specific and, although interesting, are too numerous to list here and have been discussed in the relevant sections. Red blood cells of several species of marsupial differ from those in placental mammals by having higher haemoglobin concentration and haematocrit, lower ATP and higher 2,3-diphosphoglycerate concentrations. These features are consistent across the majority of marsupial species, but the relevance of these variations from red cell metabolism in the placental mammals is unknown.

Although extensive studies have been performed on human erythrocytes, there is a shortage of information on marsupial erythrocytes. Studies on haematology and biochemistry are useful in the ecomanagement of these animals especially those in wildlife parks and zoos. The present review summarises our findings from ∼30 species of marsupials. As marsupials show great diversity in physical and behavioural characteristics, it is not surprising that examination of their red blood cells reveals variation in the biochemical features. Many variations in red cell biochemistry appear to be species specific and, although interesting, are too numerous to list here and have been discussed in the relevant sections. Red blood cells of several species of marsupial differ from those in placental mammals by having higher haemoglobin concentration and haematocrit, lower ATP and higher 2,3-diphosphoglycerate concentrations. These features are consistent across the majority of marsupial species, but the relevance of these variations from red cell metabolism in the placental mammals is unknown.

Recent studies have established that urea alters the activity of several volume-sensitive cation transport pathways. However, it has remained unclear whether urea has any effect on transport pathways that are not volume-sensitive. We examined the effect of urea on Na-K pump in the human erythrocytes. In cells from nine subjects, 500 mM urea inhibited 52 +/- 10% of the pump activity measured as the ouabain-sensitive (OS) K influx. Urea inhibited the OS K influx reversibly, in a concentration-dependent manner. [3H] oubain binding, a measure of the number of Na-K pump sites remained unchanged with urea. Urea decreased the Vmax for ouabain-sensitive K influx, but did not alter the apparent K(m) for external K. Furthermore, urea did not alter the apparent K(m) for intracellular Na. The ion turnover per pump site was decreased in the presence of urea. Thus, physiologically relevant urea concentration inhibit the Na-K pump in human erythrocyte. The inhibition of the Na-K pump by urea suggests that the effects of urea may not be limited to volume-sensitive transporters, but may be more widespread.

Cigarette smoking is an adverse prognostic factor for health. Its damaging effects on many enzymatic and cellular activities are well known. The present study was carried out to evaluate whether there is a difference in the binding of bilirubin to the erythrocytes from healthy smokers and non-smokers. The results suggest that the binding of bilirubin to the erythrocytes from healthy smokers as well as in vitro smoked erythrocytes is significantly higher than that of healthy non-smokers.

Blackgram (Vigna mungo L. Hepper) seeds contain two galactose-specific lectins, BGL-I and BGL-II. BGL-I was partially purified into two monomeric lectins which were designated as BGL-I-1 (94 kDa) and BGL-I-2 (89 kDa). BGL-II is a monomeric lectin of 83 kDA. The purified lectins were associated with galactosidase activities. BGL-I-1 and BGL-II were copurified with α-galactosidase activity while BGL-I-2 was largely associated with β-galactosidase activity. These lectins agglutinate trypsin treated rabbit erythrocytes, but not the human erythrocytes of A, B or O groups. They were stable between pH 3·5 and 7·5 for their agglutination. The lectins did not show any metalion requirement. They were inactivated at 50°C. The lectin activity was inhibited by D-galactose (0·1 mM). The Scatchard plots of galactose binding to these lectins are nonlinear and biphasic curves indicative of multiple binding sites. The data show that the monomeric lectins have both lectin and galactosidase activities suggestive of a bifunctional protein.

For studies of the charge characteristics of human erythrocytes loaded with cryoglobulins the cells should be stored in Alsever solution with 0.1% sodium azide no longer than 1 week after blood collection. Erythrocytes should be loaded with cryoglobulins by incubation during at least 4 h, the final concentration of cryoproteins in the solution being no lower than 30 microg/ml.

Effects of cadmium on glucose transport in rat adipocytes and human erythrocytes: stimulation of GLUT1 catalytic activity

Iotrolan is a non-ionic hexa-iodinated dimeric contrast agent suitable for Ct enhancement, angiography, urography and the opacofocation of body cavities. It is more hydrophilic than any other X-ray contrast agent and is sweet to tast. Iotrolan 280 is isotnoc to blood and its pharmacokinetics are almost identical to other urographic contrast agents. The experiments reported in this review show very little protein binding, enzyme inhibition or injury to membranes of human erythrocytes, rat mast cells or cultured human enfothelial cells. Osmotically induced side effects, such as vascular pain, endothelial damage, disturbance of the blood-brain barner, vaso-contruction and hemodilution are greatly reduced or absent. In various studies in rats and dogs, the mechanical and electrical function of the heart and myocardial perfusion remained almost unaffected. In rats, renal tolerance of iotrolan was superior to that of a non-ionic monomer when the contrast agents were-infused into the renal arteries. The renal tolerance after intravenous injection depends on the anomal species and experimental conditions, with favorable results in most cases. The intravenous, LD 50 is very high and seems to be restricted more by physical overload of the animals tahn b osmotic or chemotoxic effects. Due to reduced osmotic diultion the contrast efficacy is slightly better than higher osmolality agents.

The haemolytic effects of a series of amphiphilic calix-arene derived Solid LipidNanoparticles (SLNs) have been measured on human erythrocytes. The effectsof both the hydrophobic chain length and the nature of the polar head-groups on theamphiphilic calix[4]arene have been investigated. For all systems, no haemolyticeffects are observed.

We have compared effects of dimethylsulfoxide (Me2SO) and two polyols on the Ca(2+)-ATPase purified from human erythrocytes. As studied under steady-state conditions over a broad solute concentration range and temperature, Me2SO, glycerol, and xylitol do not inhibit the Ca(2+)-ATPase activity; this is in contrast to numerous other organic solutes that we have investigated. Under specific experimental conditions, Me2SO (but not glycerol) substantially increases Ca(2+)-ATPase activity, suggesting a possible facilitation of enzyme oligomerization. The activation is more pronounced at low Ca2+ concentrations. In contrast to glycerol, Me2SO shows no protective effect on enzyme structure as assessed by determining residual Ca(2+)-ATPase activity after exposing the enzyme to thermal denaturation at 45 degrees C. Under these conditions several other organic solutes strongly enhance the denaturating effect of temperature. Because of the temperature dependence of its effect on the Ca(2+)-ATPase activity we believe that Me2SO activates the Ca(2+)-ATPase by indirect water-mediated interactions.

Vesiculation of the plasmalemma followed by fragmentation to microvesicles and formation of microspherocytes are shown to be the main phenomena during aging in rat erythrocytes. In human erythrocytes microvesiculation from the apexes of echinocyte spicules and hemolysis in echinocytes II–IV are predominant. Hemolysis, vesiculation, and microvesiculation are observed in rabbit, and hemolysis and microvesiculation in canine erythrocytes. An increased level of free fatty acids (about 30% per hour) in human and rat erythrocytes is also detected.

Background Plasmodium falciparum is the most malignant agent of human malaria. It belongs to the taxon Laverania, which includes other ape-infecting Plasmodium species. The origin of the Laverania is still debated. P. falciparum exports pathogenicity-related proteins into the host cell using the Plasmodium export element (PEXEL). Predictions based on the presence of a PEXEL motif suggest that more than 300 proteins are exported by P. falciparum, while there are many fewer exported proteins in non-Laverania. Results A whole-genome approach was applied to resolve the phylogeny of eight Plasmodium species and four outgroup taxa. By using 218 orthologous proteins we received unanimous support for a sister group position of Laverania and avian malaria parasites. This observation was corroborated by the analyses of 28 exported proteins with orthologs present in all Plasmodium species. Most interestingly, several deviations from the P. falciparum PEXEL motif were found to be present in the orthologous sequences of non-Laverania. Conclusion Our phylogenomic analyses strongly support the hypotheses that the Laverania have been founded by a single Plasmodium species switching from birds to African great apes or vice versa. The deviations from the canonical PEXEL motif in orthologs may explain the comparably low number of exported proteins that have been predicted in non-Laverania.

Blood stages of Plasmodium falciparum cause the pathology of malaria; however, the progression of the parasite through this complex part of the life cycle has never been visualized. In this study, we use four-dimensional imaging to show for the first time the development of individual parasites in erythrocytes and the concomitant host cell modifications. Our data visualize an unexpectedly dynamic parasite, provide a reference for this life cycle stage and challenge the model that protein export in P. falciparum is linked to the biogenesis of host cell modifications termed Maurer's clefts. Our results provide a novel view of the blood-stage development, Maurer's cleft development and protein export in malaria parasites, and open the door to study dynamic processes, drug effects and the phenotype of mutants.

Raman spectra were used to study the effects of the phosphorylated amino acids on the erythrocyte membrane. It was found that some phosphorylated amino acids might cause the polar part of the membrane phospholipid to become less ordered, the packing of the chains to become looser, and the end of the chain more ordered. Some of the phosphoamino acids cause the phospholipids' all-trans/gauche ratio to increase and some cause them to decrease. This could give some clues to the function of phosphorylated proteins in the biological process concerning the change in membrane mobility.

Background Magnetic fractionation of erythrocytes infected with Plasmodium falicparum has several research uses including enrichment of infected cells from parasite cultures or enhanced detection of P. falciparum gametocytes. The aim of the present study was to quantitatively characterize the magnetic fractionation process and thus enable optimization of protocols developed for specific uses. Methods Synchronized cultures of P. falciparum parasites incubated with human erythrocytes were magnetically fractionated with commercially available columns. The timing of the fractionation experiments was such that the parasites were in second half of their erythrocytic life cycle with parasite densities ranging from 1 to 9%. Fractionations were carried out in a single pass through the columns. Cells were enumerated and differentiated in the initial samples as well as in the positive and negative fractions. The capture of cells by the fractionation column was described by a saturation binding model. Results The magnetic binding affinity to the column matrix was approximately 350 times greater for infected cells compared with uninfected cells. The purity of infected cells in the captured fraction was generally >80% but decreased rapidly (to less than 50%) when the number of infected cells that passed through the column was substantially decreased (to less than 9 ± 5 × 105 cells). The distribution of captured parasite developmental stages shifted to mature stages as the number of infected cells in the initial samples and flow rate increased. The relationship between the yield of infected cells in the captured fraction and flow rate of cells conformed to a complementary cumulative log-normal equation with flow rates >1.6 × 105 cells per second resulting in yields Conclusions A detailed quantitative analysis of a batchwise magnetic fractionation process for malaria infected erythrocytes using high gradient magnetic fractionation columns was performed. The models applied in this study allow the prediction of capture efficiency if the initial infected cell concentration and the flow rate are known.

Human erythrocytes were exposed to extracts of Codium fragile ssp. tomentosoides, Ascophyllum nodosum, Dolichos biflorus seeds and a solution of purified polyphenols from Ascophyllum nodosum. In each case the erythrocytes appeared to agglutinate. Agglutinates were examined by scanning electron microscopy. Photomicrographs of the erythrocytes exposed to lectin-containing extracts of C. fragile and D. biflorus showed the typical appearance of agglutinated cells. Photomicrographs of the erythrocytes exposed to the crude extract and purified polyphenols from A. nodosum were similar to each other, but quite different in appearance to erythrocytes agglutinated by the lectins from C. fragile and D. biflorus. This evidence adds further support to the contention that lectin presence recorded in brown algal extracts is largely due to ‘pseudoagglutination’ produced by polyphenols contained in these extracts.

At dextran (Mw approximately 500,000) concentrations from 2 to approximately 10%, suspensions of normal human erythrocytes flocculate in small convex agglutinates. At dextran concentrations greater than 10%, the erythrocytes resegregate in a stable monodisperse suspension. At all these dextran concentrations, the erythrocytes are coated with considerable amounts of dextran. It can be argued that at dextran concentrations from 2 to 10%, as well as at dextran concentrations greater than 10%, there is a thin layer, which is depleted of dextran, between the dextran layer adsorbed onto the erythrocytes and the bulk dextran solution. It can also be shown that there is a repulsive interaction between the two layers of dextran: one adsorbed and one free. When the adsorbed dextran layer is the most concentrated, stability must ensue, and when the dextran in free solution is the most concentrated, flocculation should occur. Below 7% dextran, the concentration of free dextran is higher than the adsorbed concentration; above 10% dextran that situation is reversed. These data correlate well with the depletion flocculation predicted for the lower concentration and the depletion stabilization predicted for the higher dextran concentration.

The interaction of galactose oxidase with native and desialylated glycophorin A was studies by oxidizing human erythrocytes and globoside/phospholipid vesicles with the enzyme. Oxidation of the glycolipid was improved in the presence of vesicle-incorporationted glycophorin A. Although galactose oxidase is a very basic protein, it was not adsorbed on native human erythrocytes. Instead, neuraminidase-treated cells bound a substantial amount of galactose oxidase, but the enzyme seemed to be released into the buffer when desialylated glycoproteins had been oxidized.

The effect of native venom of red (spitting) cobra (Naja pallida) on human erythrocytes is studied using the methods of electron microscopy and filtration through Millipore filters. Morphological analysis reveals marked transformation of discoid erythrocytes to echinocytes. More prolonged contact of the blood with the venom impairs the deformability of erythrocytes and induces hemolysis and the sludge syndrome. The results indicate a potent cytotoxic effect of native venom of red cobra.

It is shown that a helium pressure of 100 kgs/cm2 (9.81 MPa) inhibits acetylcholinesterase of erythrocytes within nonsaturation concentrations of the substrate and has no effect within saturation conditions. This effect is assumed to be one of the possible mechanisms of biological action of hyperbaria.

It is found that 3-deoxy-3-iodine-glucose (3D-I-glucose) enters both erythrocytes and tumor cells at a rate close to that of glucose entry. For tumor cells the total uptake of the preparation was 6-fold higher than for erythrocytes (1500 and 250 μM/mln. cells, respectively). Phosphorylated products of 3D-I-glucose were not detected; however, the total amount of preparation in the probes dropped during incubation, indicating that it is metabolized by the cells.