Abstract Throughout their life span, circulating red blood cells (RBCs) transport oxygen (O(2)) primarily from the lungs to tissues and return with carbon dioxide (CO(2)) from respiring tissues for final elimination by lungs. This simplistic view of RBCs as O(2) transporter has changed in recent years as other gases, for ...

Over 25 years ago Francis reported an association between blood transfusion and worsened cancer prognosis. Subsequently there has been much debate over whether there is in fact such an association, and if so, what is its underlying mechanism. Allogeneic blood transfusion is the most frequent allo-transplantation procedure performed on a routine ...

Interstitial laser thermotherapy was used to treat rat liver tumours. The aim was to investigate the influence of temperature and temporary hepatic inflow occlusion on tumour growth and blood perfusion. Liver tumours were treated at 44°C at the tumour border for 30 minutes, hepatic inflow occlusion only, or a combination of ...

Cancers of the brain are intrinsically more complicated to treat than systemic malignancies due to the unique anatomical features of the brain. The blood-brain barrier prevents chemotherapeutic agents from reaching brain neoplasms, and angiogenesis occurs as the metabolic needs of the tumour increase, thus further complicating treatment. The newly formed ...

Anemia is a serious problem in critically ill neonates. To investigate the pathophysiology of anemia and responses to red blood cell (RBC) transfusions and erythropoietin therapy, repeated measurement of red blood cell volume (RCV) and blood volume is useful. To extend our previous sheep study in which RBCs were labeled ...

To investigate the pathophysiology of anemia and responses to red blood cell (RBC) transfusions and erythropoietin, repeated measurement of the circulating red blood cell volume (RCV) would be useful. Ovine erythropoiesis is similar to human erythropoiesis. Accordingly, a method for measuring RCV using either human or sheep RBCs labeled at ...

During storage of red blood cell (RBCs) before transfusion, RBCs undergo a series of structural and functional changes that include the exposure of phosphatidylserine (PS), a potent removal signal. It was postulated that, during blood bank storage, the susceptibility to stress-induced PS exposure increases, thereby rendering a considerable fraction of ...

Safe, accurate methods permitting simultaneous and/or repeated measurement of red blood cell (RBC) survival (RCS) are important to investigate pathophysiology and therapy of anemia. Methods using chromium 51 ((51) Cr)-labeled RBCs are unacceptable for infants, children, and pregnant women. We report RCS measured in vivo using RBCs labeled with several ...

The mechanisms involved in the formation of red blood cell (RBC) microparticles in vivo as well as during erythrocyte storage are reviewed, and the potential role of microparticles in transfusion medicine is described. Microparticles release is an integral part of the erythrocyte ageing process, preventing early removal of RBCs. Proteomics ...

Blood is a concentrated suspension of red blood cells (RBCs). Motion and deformation of RBCs can be analyzed based on knowledge of their mechanical characteristics. Axisymmetric models for single-file motion of RBCs in capillaries yield predictions of apparent viscosity in good agreement with experimental results for diameters up to about ...

A high-precision microfluidic viscometer with a microfluidic channel array composed of 100 indicating channels is demonstrated in this study. The relative viscosity of the sample fluid could be measured by simply counting the number of the indicating channels occupied by the sample and the reference fluids. Using lumped parameter modeling, ...

Usually, investigations of erythrocyte aggregation at rest are focused on effects of the strength of erythrocyte-erythrocyte attractive interactions and the volume fraction of the cells, whereas the role of prior flow velocity has not been thoroughly investigated. The aim of this study is to fill this gap. The main conclusions ...

The spatial characteristics of blood viscosity were investigated by combining a newly developed constitutive equation with shear deformation fields calculated from velocity measurements obtained by a μPIV based technique. Blood at physiological hematocrit levels and in the presence of aggregation was sheared in a narrow gap plate-plate geometry and the ...

Whole-blood viscosity is increasingly being recognized as a factor implicated in the vascular disease progression in high-risk chronic kidney disease patients. Intermittent hemodialysis and hemodiafiltration sessions, characterized by rapid volume changes and anemia correction by erythropoietin stimulating agents, are favorable conditions for enhancing whole-blood viscosity changes and consequently triggering cardiovascular ...

A disposable on-chip whole blood/plasma separator, which is able to separate plasma from whole human blood by capillary force through a bead-packed microchannel, has been designed, fabricated and characterized in this work. Various sizes of silica beads were slurry-packed through a microchannel using a bump structure which held beads in ...

Hypoxia is a major cause of painful vaso-occlusive crisis in sickle cell disease (SCD). Simple transfusion and red blood cell (RBC) exchange are commonly used as preventive therapies whose aim is to dilute hemoglobin (Hb)S-containing RBCs (SS-RBCs) with normal RBCs (AA-RBCs) to prevent sickling. We hypothesized that the effectiveness of ...

Viscosity of blood substitutes is among the important determinants to restore microcirculation. Sodium alginate (SA) is always mentioned as "viscosity modifier" in creating blood substitutes. In the present study, the whole blood was diluted using SA solutions to final hematocrits of 10%, 20%, and 35%, respectively. The whole blood viscosity ...

Background and Objectives  Conventional quality control studies of the shelf life of RBC units do not consider cold chain interruptions that occur during cross-matching or between the release of RBCs from the blood bank and their return from the ward. These interruptions may, however, lead to a considerable loss of ...

There has recently been a great deal of interest in noninvasive high-frequency ultrasound imaging of small animals such as rats due to their being the preferred animal model for gene therapy and cancer research. Improving the interpretation of the obtained images and furthering the development of the imaging devices require ...

From the flow properties of dense granular suspensions on an inclined plane, we identify a mesoscopic length scale strongly increasing with volume fraction. When the flowing layer height is larger than this length scale, a diverging Newtonian viscosity is determined. However, when the flowing layer height drops below this scale, ...

Red blood cell (RBC) product wastage in hospitals is reported to range from 0.1% to 6.7%. Wastage at our institution averaged 4.4% of 63,000 issued RBC products. Data indicated that approximately 87% of wasted RBC units were either individual units that were out of blood bank for more than 30 ...

Many countries use cooling plates to actively cool collected whole blood (WB) to room temperature. Until now, no paired comparison had been performed, and it was our aim to compare the effect of active versus no active cooling on the in vitro quality of WB and subsequently prepared blood components. ...

As the predominant cell type in blood, red blood cells (RBCs) and their biomechanical properties largely determine the rheological and hemodynamic behavior of blood in normal and disease states. In sickle cell disease (SCD), mechanically fragile, poorly deformable RBCs contribute to impaired blood flow and other pathophysiological aspects of the ...

OBJECTIVE: To evaluate N-hydroxysuccinimide (NHS)-biotin labeling of equine RBCs and determine posttransfusion survival of autologous equine RBCs stored in citrate phosphate dextrose adenine-1 (CPDA-1) for 0, 1, 14, and 28 days. ANIMALS: 13 healthy adult Thoroughbreds. PROCEDURES: Serial dilutions of biotin and streptavidin-phycoerythrin (PE) were evaluated in vitro in blood ...

Tissue occlusion and the hyperaemic response upon reperfusion can be used as a tool to assess microvascular function in various vascular diseases. Currently, laser Doppler flowmetry (LDF) is applied most often to measure hyperaemic responses. In this study, we have applied tissue viability imaging (TiVi) and LDF to measure the ...

BACKGROUND: Salvage and return of unwashed shed blood (USB) after total knee replacement (TKR) is an established blood-saving technique, but some authors question its efficacy and safety and suggest that the shed blood be washed before returning. We evaluated a colloid-based sedimentation method for improving and standardizing the quality of ...

We use a simple model of micro-vascular blood flow to explore conditions that give rise to multiple equilibrium states in a three-node micro-vascular network. The model accounts for two primary rheological effects: the Fåhraeus-Lindqvist effect, which describes the apparent viscosity of blood in a vessel, and the plasma skimming effect, ...

Transverse and longitudinal dispersion in gravity stable, favourable viscosity ratio flows are investigated and compared with earlier data obtained for miscible fluids and for tracer flow. Data from laboratory measurements of longitudinal dispersion in low viscosity ratio (8.63×10(-)(4)) and high density contrast (471kgm(-)(3)) displacements are compared with literature data for ...

Like most teleosts, sablefish (Anoplopoma fimbria Pallas 1814) blood exhibits a moderate Root effect (~35% maximal desaturation), where a reduction in blood pH dramatically reduces O(2) carrying capacity, a mechanism important for oxygenating the eye and filling the swim bladder (SB) in teleosts. Although sablefish lack a SB, we observed ...

In micromixer studies, compared with the design, modeling and characterization, the influence of the fluid properties on mixing has been less discussed. This topic is of practical significance as the properties of diverse biological and chemical liquids to be mixed have large variations. Here, we report a microfluidic mixer for ...

In this study, we investigated the differences between pulsatile cardiopulmonary bypass (CPB) procedure and nonpulsatile CPB procedure in terms of their effects on hemolysis and deformability of red blood cells (RBCs) under various shear stress conditions. In order to research the effects on hemolysis and deformability, four parameters--free hemoglobin (fHb) ...

The rigidity of red blood cells (RBCs) plays an important role in whole blood viscosity and is correlated with several cardiovascular diseases. Two chemical agents that are commonly used to study cell deformation are diamide and glutaraldehyde. Despite diamide's common usage, there are discrepancies in the literature surrounding diamide's effect ...

Psychological factors, such as stress, anxiety, depression, as well as immuno-inflammatory processes may influence blood rheology. On the other hand, these factors may be involved in triggering, aggravating or maintenance of urticaria symptoms. The present study was designed to compare blood rheological properties of patients with chronic urticaria with positive ...

Koala, a marsupial, and echidna, a monotreme, are mammals native to Australia. Blood viscosity (62.5-1250s(-1)), red blood cell (RBC) deformability, RBC aggregation, aggregability and surface charge, and hematological parameters were measured in blood samples from six koalas and six echidnas and compared to adult human blood. Koala had the largest ...

To approach the real haemolytic process of jellyfish toxins, both in vitro and in vivo haemolysis of tentacle-only extract (TOE) from jellyfish Cyanea capillata has been studied. Dose-response curves of the haemolytic activity of TOE in vitro were sigmoid shaped in both erythrocyte suspension and diluted whole blood, with the ...

BACKGROUND/PURPOSE: Betel quid (BQ) chewing is a popular oral masticatory activity, and there are approximately 600 million BQ chewers worldwide. Although chewing BQ has been linked to the patho-genesis of oral cancer, leukoplakia, and oral submucous fibrosis. The question whether the mixed constituents present in areca nut, which may exert ...

Dendrimers are global macromolecules with promising biomedical application. In order to investigate their blood compatibility, different generations of polyamidoamine (PAMAM) dendrimers terminated with different types of surface functional groups were incubated with red blood cells (RBC) for time course of haemolysis assay and RBC morphology observation. Cationic PAMAM dendrimers demonstrated ...

Employing high-speed camera laser-scanning confocal microscopy with RBC-tracking software, we previously showed that RBC velocities in intraparenchymal capillaries of rat cerebral cortex are distributed over a wide range. In the present work, we measured RBC velocities in mice, whose body weights are less than one-tenth of that of rats. In ...

Decreasing blood viscosity has been proposed since the advent of hemodilution as a means for increasing perfusion in many pathological conditions, and increased plasma viscosity is associated with the presence of pathological conditions. However, experimental studies show that microvascular functions as represented by functional capillary density in conditions of significantly ...

Some studies indicate that obesity is associated with rheological disturbances. Because there are usually sex differences in the type of obesity we decided to evaluate rheological differences between male and female obese patients. We studied 18 morbidly obese men, mean age 43.66 +/- 11.32 years, mean body mass index (BMI) ...

In recent years, the engineering of blood viscometers for the diagnosis, prognosis, and prevention of cardiovascular and other diseases has been the subject of significant research interest. Conventional blood viscometers such as rotational viscometers and capillary viscometers typically rely on mechanical techniques in quantifying whole-blood viscosity, a process in which ...

Mechanical and electrical properties of red blood cells (RBC) suspensions in dextran 70 (Dx70), dextran 150 (Dx150), dextran 500 (Dx500) and polyethileneglycol (PEG) 35,000 with different concentrations were evaluated through apparent viscosity and conductivity measurements under steady and unsteady flow conditions. RBCs suspensions of the washed RBS in PBS (control) ...

Biochemical solutions have a wide range of hydrophilicity (contact angle and surface tension) and viscosity. A critical challenge is that microfluidic systems typically need expensive or complex pumps to control the various parallel biochemical streams. In this study, without using any pumps, we present a simple scheme that controls the ...

The aim of our study was to compare hemorheological consequences of hemotransfusion and recombinant human erythropoetin treatment in anemic cancer patients. Forty anemic patients with solid nonmyeloid malignancies were enrolled in this prospective, open-label study. Both prior to and following treatment (epoetin beta, 10,000 units subcutaneously thrice weekly, for four ...

Whole blood viscosity is affected by a number of factors, among which plasma proteins are a major component. They exert their effects either directly or through their influence on red cell aggregation. Changes in fibrinogen and in immunoglobulins, under both physiologic and pathologic conditions can increase whole blood viscosity. Blood ...

The flow properties of blood and its components vary widely throughout the animal kingdom. Even if nucleated avian and reptile red blood cells (RBC) are excluded from the analysis, RBC exhibit different rheological behavior among mammalian species. Both RBC aggregation and cellular deformability have been reported to vary among species, ...

BACKGROUND: The structural and biochemical changes to erythrocytes during storage, called 'storage lesion', are important factors that contribute to decreases in the efficacy and safety of blood transfusions. However, the biochemical mechanisms are only partly understood. STUDY DESIGN AND METHODS: Fresh whole blood in citrate phosphate dextrose anticoagulant was preserved ...

Our aim was to perform a preliminary study of blood flow in the peripheral microcirculation in patients with heart failure. Cardiac patients were investigated to establish possible microcirculatory changes due to this pathology. We evaluated 16 patients (non-smokers, dislipidemic with hypercholesterolemia), receiving oral treatment and in NYHA class 2.3 +/- ...

The present work aims to study the effects of the blood-microstructure on the electrical conduction from two different but correlated properties: Electrical and mechanical (viscosity), and to derive useful parameters for the evaluation of electrical conduction as a function of the blood viscosity. ac-conductivity and dielectric constant of normal and ...

BACKGROUND: Hemorheologic factors such as red blood cell (RBC) aggregation and deformability differ according to species. In many comparative hemorheologic studies, only venous blood samples have been used for measurements. There is little published information comparing arterial and venous blood differences between species. We compared hemorheologic factors in arterial and ...