scholarly journals Micro-Rheological Changes of Red Blood Cells in the Presence of an Arterio-Venous Fistula or a Loop-Shaped Venous Graft in the Rat

2020 ◽  
Vol 11 ◽  
Author(s):  
Balazs Szabo ◽  
Bence Tanczos ◽  
Adam Varga ◽  
Barbara Barath ◽  
Souleiman Ghanem ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Loop Group ◽  
Erythrocyte Aggregation ◽  
Rheological Parameters ◽  
Loop Groups ◽  
Access Methods ◽  
Minimal Impact ◽  
Hind Limbs ◽  
Venous Fistula

Introduction: In case of kidney failure, hemodialysis is the primary kidney replacement technique. Several vascular access methods used for the therapy, one of which is the arterio-venous fistula (AVF). In the AVF, the blood flow is altered, which can elevate the mechanical stress on the red blood cells (RBCs). This can affect the RBC hemorheological properties, and it can further cause systemic changes. To lower the turbulence and shear stress, we performed a loop-shaped arterio-arterial venous interposition graft (loop-shaped graft) to compare its effect to the conventional AVF.Materials and Methods: Thirty male Wistar were used (permission registration Nr.: 25/2016/UDCAW). The animals were randomly divided into sham-operated, AVF, and loop groups (n = 10/each). The superficial inferior epigastric vein (SIEV) was used to create the AVF and the loop-shaped graft. Blood samples were taken before/after the surgery and at the 1st, 3rd, and 5th postoperative weeks. We measured hemorhelogical, hematological, and blood gas parameters. The microcirculation of the hind limbs was also monitored using Laser Doppler fluxmetry.Results: Hematocrit, RBC count, and hemoglobin decreased by the 1st postoperative week. The erythrocyte aggregation values significantly increased in the fistula group by the 5th week (6.43 ± 2.31 vs. 13.60; p < 0.0001; vs. before operation). At the postoperative 1st week in the loop group, the values showed a significant decrease in RBC deformability. During the maturation period, dominantly at the 5th week, all values were normalized. The operated hind limb’s skin microcirculation significantly increased in the sham and loop group by the 1st week (39 ± 10.57 vs. 73.93 ± 1.97 BFU, p < 0.01). This increase wasn’t observed in the fistula group probably due to a steal-effect.Conclusion: Unlike in the loop group, in the presence of the fistula, several rheological parameters have changed. The loop-shaped graft had only minimal impact on micro-rheological parameters.

Arterio-venous fistula for automated red blood cells exchange in patients with sickle cell disease: Complications and outcomes

2016 ◽  
Vol 92 (2) ◽  
pp. 136-140 ◽  
Author(s):  
Marianne Delville ◽  
Sandra Manceau ◽  
Nassim Ait Abdallah ◽  
Jan Stolba ◽  
Sameh Awad ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Red Blood Cells ◽  
Sickle Cell ◽  
Blood Cells ◽  
Cell Disease ◽  
Venous Fistula

The squeezing of red blood cells through capillaries with near-minimal diameters

1989 ◽  
Vol 203 ◽  
pp. 381-400 ◽  
Author(s):  
D. Halpern ◽  
T. W. Secomb
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Cell Shape ◽  
Numerical Solutions ◽  
Tube Diameter ◽  
Red Cells ◽  
Rheological Parameters ◽  
Red Cell ◽  
Red Cell Membrane ◽  
Intact Cells

An analysis is presented of the mechanics of red blood cells flowing in very narrow tubes. Mammalian red cells are highly flexible, but their deformations satisfy two significant constraints. They must deform at constant volume, because the contents of the cell are incompressible, and also at nearly constant surface area, because the red cell membrane strongly resists dilation. Consequently, there exists a minimal tube diameter below which passage of intact cells is not possible. A cell in a tube with this diameter has its critical shape: a cylinder with hemispherical ends. Here, flow of red cells in tubes with near-minimal diameters is analysed using lubrication theory. When the tube diameter is slightly larger than the minimal value, the cell shape is close to its shape in the critical case. However, the rear end of the cell becomes flattened and then concave with a relatively small further increase in the diameter. The changes in cell shape and the resulting rheological parameters are analysed using matched asymptotic expansions for the high-velocity limit and using numerical solutions. Predictions of rheological parameters are also obtained using the assumption that the cell is effectively rigid with its critical shape, yielding very similar results. A rapid decrease in the apparent viscosity of red cell suspensions with increasing tube diameter is predicted over the range of diameters considered. The red cell velocity is found to exceed the mean bulk velocity by an amount that increases with increasing tube diameter.

scholarly journals Changes in the morphology of erythrocytes after in vitro exposure of blood to carbon monoxide

2019 ◽  
Vol 47 (7) ◽  
pp. 669-678
Author(s):  
E. K. Kozlova ◽  
V. A. Sergunova ◽  
A. P. Kozlov ◽  
E. A. Sherstyukova ◽  
O. E. Gudkova
Keyword(s):  
Carbon Monoxide ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Structural Damage ◽  
Test Tube ◽  
Erythrocyte Aggregation ◽  
Erythrocyte Membranes ◽  
Blood Levels ◽  
Cell Diameter

Background: One of the pathological effects of carbon monoxide (CO) on blood is the formation of carboxyhemoglobin. Carboxyhemoglobin completely blocks oxygen transfer; therefore, there is a net decrease in oxygen transport by red blood cells potentially resulting in tissue hypoxia. The effects of CO on blood can also damage cell membranes. Atomic force microscopy (AFM) has been recognized as effective for investigation into the mechanisms of structural damage in erythrocyte membranes. Aim: By means of AFM, to identify characteristics of changes in morphology and aggregation of erythrocytes exposed to CO in vitro.Materials and methods: All experiments were performed in vitro. We studied the morphology of erythrocytes and their aggregates with AFM. Blood sampling (150 μl) in microvettes with EDTA (Sarstedt AG & Co., Germany) was carried out during a prophylactic work-up of 5 volunteers. To obtain CO in a test tube, formic acid was mixed with sulfuric acid 1:1. Blood levels of carboxyhemoglobin were measured by spectrophotometry. A nonlinear fitting method of the experimental spectra was used to calculate the concentrations of hemoglobin derivatives in blood. Statistical analysis was done with the Origin software (OriginLab Corporation, Northampton, MA, USA).Results: After CO exposure, a shift in peaks was observed. At exposure time t₂=320 s, the percentage of carboxyhemoglobin (CHbCO) was 88±2%. As a result of blood exposure to CO, at t₁=160 s 10% of the cells differed in their shape from discocytes, whereas at t₂=320 s their proportion was 38%. With increasing duration of exposure to CO, erythrocyte aggregation occurred with formation of their large conglomerates up to 30 μm in size. In the control smear, the proportion of discocytes was 96±2%, and the remaining 4±1% of the cells had the form of echinocytes. The cell diameter (Dcont) was in the range 7.5±0.8 μm. After blood exposure to CO at t₁=160 s in the monolayer, 28±5% of cells had a diameter less than<5.7 μm. After CO exposure at t₂=320 s, the proportion of cells with a diameter of less than<5.7 μm increased to 72±11%.Conclusion: The experiments have shown that blood exposure to CO changed the morphology of erythrocytes. The formation of interconnected structures made of red blood cells was observed. With increased time of exposure, erythrocytes demonstrated aggregation with conglomerate formation.

Effects of contrast media on erythrocyte aggregation during sedimentation

2003 ◽  
Vol 81 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Xuequn Huang ◽  
Akio Yoshikoshi ◽  
Kunihiro Hirano ◽  
Akio Sakanishi
Keyword(s):  
Contrast Media ◽  
Stationary Phase ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Erythrocyte Aggregation ◽  
Collision Rate ◽  
Autologous Plasma ◽  
Erythrocyte Sedimentation ◽  
Rbc Aggregation ◽  
In Cells

To evaluate the effects of contrast media (CMs) on erythrocyte aggregation, we measured the erythrocyte sedimentation with Westergren method at 25°C. CMs were diatrizoate (Urografin® 76%) for ionic CM and iopamidol (Iopamiron® 370) for nonionic CM. Swine red blood cells (RBCs) were suspended in autologous plasma containing diatrizoate (URO), iopamidol (IOP), and saline (SAL) at 6.7% w/w, as well as in plasma alone (PLA), at 40% of the hematocrit. Sigmoid sedimentation curves were fitted to the Puccini et al. (1977) equation, and the average number of RBCs per aggregate m was calculated by Stokes' law against the time t. According to the Murata–Secomb (1988) theory we estimated the collision rate K between two aggregates from dm/dt in the stationary phase during sedimentation. Corresponding to the maximal ESR, the dm/dt (in cells/s) was 0.52 in PLA, 0.09 in SAL, 0.06 in URO and 0.03 in IOP, so that K also decreased in proportion to dm/dt from 145 fL/s in PLA to 8 fL/s in IOP. Both the ionic and nonionic CMs tend to inhibit the RBC aggregation more than that in SAL; the latter iopamidol appears to be inhibitory more than the former diatrizoate in autologous plasma.Key words: erythrocyte sedimentation, RBC aggregation, contrast media, diatrizoate, iopamidol.

Effects of erythrocyte aggregation and venous network geometry on red blood cell axial migration

2001 ◽  
Vol 281 (2) ◽  
pp. H939-H950 ◽  
Author(s):  
Jeffrey J. Bishop ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Cell Aggregation ◽  
Erythrocyte Aggregation ◽  
Segment Length ◽  
Branch Points ◽  
Glass Tubes ◽  
A Cell

Axial migration of red blood cells in small glass tubes can cause blood viscosity to be effectively independent of shear rate. However, this phase separation may not occur to the same degree in the venous network due to infusion of cells and aggregates at branch points. To investigate this hypothesis, we followed trajectories of fluorescently labeled red blood cells in the venular network of the rat spinotrapezius muscle at normal and reduced flow with and without red blood cell aggregation. Cells traveling near the wall of an unbranched venular segment migrated ∼1% of the longitudinal path length without aggregation and migrated slightly more with aggregation. Venular segment length between branch points averaged three to five times the diameter. Cells in the main vessel were shifted centrally by up to 20% of diameter at branch points, reducing the migration rate of cells near the opposite wall to <1% even in the presence of aggregation. We conclude that formation of a cell-free marginal layer in the venular network is attenuated due to the time dependence of axial migration and the frequent branching of the network.

scholarly journals PRELIMINAR STUDY OF THE EFFECTS OF GAMMA RADIATIONS ON HUMAN RED BLOOD CELLS

Anales AFA ◽  
2020 ◽  
Vol 31 (2) ◽  
pp. 51-54
Author(s):  
E. Estrada ◽  
H. Castellini ◽  
A. Acosta ◽  
L. Di Tullio ◽  
J. Borraz ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Membrane Surface ◽  
Erythrocyte Aggregation ◽  
Blood Samples ◽  
Human Red Blood Cells ◽  
Aggregation Parameters ◽  
Gamma Radiations ◽  
Different Levels ◽  
Different Doses

In this study, the alterations in viscoelastic and aggregation parameters of red blood cells were analyzed for usual gamma irradiation procedures for transfusion purposes. In order to determine possible hemorheological changes that may affect the health of patients and their relationship with the biochemical changes observed, the blood samples were irradiated at different doses. The results show alterations in the erythrocyte aggregation time, in the membrane surface viscosity and in the size of the aggregates in the irradiated samples, suggesting that the damage produced by the ionizing radiation affects the physical properties of red blood cell membrane at different levels.

scholarly journals Monitoring system of biophysical properties of the red blood cells of patients for medical diagnosis purposes

2020 ◽  
pp. 13-20
Author(s):  
Л.В. Батюк ◽  
Н.М. Кізілова
Keyword(s):  
Artificial Intelligence ◽  
Red Blood Cells ◽  
Monitoring System ◽  
Blood Cells ◽  
Medical Diagnostics ◽  
Erythrocyte Aggregation ◽  
High Tech ◽  
Physical Parameters ◽  
Mathematical Methods ◽  
Laboratory Equipment

Modern medical diagnostics is impossible without high-tech means of collecting information about the patient's condition, in particular, the biochemical properties of blood and other tissues, physiological signals in the format of time series, and medical images as well. Extensive use of automatic methods of information processing and decision-making based on mathematical models, expert systems, and artificial intelligence is an integral part of the tomorrow’s medicine. Such approaches significantly increase the accuracy of diagnosis and the effectiveness of the prescribed treatment, but this requires the availability of properly structured databases with the results of both successful / unsuccessful treatments, and a complete set of necessary analyses and tests for each patient. This paper discusses the most important components of such database and public health monitoring system. The main issues are the standardization of data format, approaches, methods and laboratory equipment used to unify monitoring, diagnosis and control over the treatment. The importance of using additional physical parameters of blood cells and tissues to increase the efficiency of medical diagnostics with artificial intelligence is shown. The sedimentation curves corresponding to stable normal, stable increased and unstable erythrocyte aggregation rate are given. It is shown that the time to reach the maximum cell sedimentation rate can be calculated on a 2-phase model of blood suspension, indicators of which could be accumulated in the database, which will allow the extraction of additional diagnostic information using novel statistical and mathematical methods. Typical dependences of erythrocyte dielectric constant curves on temperature for oncology patients are given. It is shown that storage in the database the values of dielectric permittivity of red blood cells measured at different temperature and  frequencies of electromagnetic fields applied in the dielectrometer, provides significant material for a more detailed study of the patterns of development of various diseases and finding the most sensitive indices for their timely detection.

Effect of Terahertz Laser Irradiation on Erythrocyte Aggregation in Healthy Blood

2013 ◽  
Vol 8 (2) ◽  
pp. 117-123
Author(s):  
Alina Munzarova ◽  
Evgeny Zelentsov ◽  
Aleksandr Kozlov
Keyword(s):  
Red Blood Cells ◽  
Terahertz Radiation ◽  
Blood Cells ◽  
Average Power ◽  
Erythrocyte Aggregation ◽  
Colloidal System ◽  
Specific Effects ◽  
The Individual ◽  
The Impact

The study is devoted to a topical field of research – the interaction of terahertz radiation with biological structures. This paper examines the impact of the Novosibirsk terahertz free electron laser on the aggregation and morphology of red blood cells of prepared blood samples in vitro. The aim of this study was to determine the safe action of the laser radiation on red blood cells and the identification of specific effects that arise in the erythrocytes under the action of terahertz radiation and lead to non-destructive disaggregation of individual cells of erythrocytes. The methodology of sample preparation of the objects, obtaining and analyzing micrographs based on the classification of red blood cells and particles model colloidal system of the area into classes corresponding to the individual and aggregate particles, was developed. Found that 5sec exposure of 200 mkl sample of red blood cells by the terahertz radiation with wavelength of 130–146 mm and an average power density of 8–10 W/cm2 does not lead to visible changes in cell morphology and the number of aggregated particles. The exposure of more than 25 seconds can lead to lysis of erythrocytes. When exposed for 10–15 sec the average number of erythrocytes in the aggregates is reduced by 10–15 % in some cases – up to 80 %

Gender differences in the expression of erythrocyte aggregation in relation to Bβ-fibrinogen gene polymorphisms in apparently healthy individuals

2006 ◽  
Vol 95 (03) ◽  
pp. 428-433 ◽  
Author(s):  
Einor Assayag ◽  
Irena Bova ◽  
Shlomo Berliner ◽  
Hava Peretz ◽  
Sali Usher ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Functional Change ◽  
Plasma Fibrinogen ◽  
Erythrocyte Aggregation ◽  
Healthy Individuals ◽  
Slide Test ◽  
Red Blood Cell Count ◽  
Blood Erythrocyte ◽  
Apparently Healthy

SummaryAn increased erythrocyte aggregation (EA) is associated with capillary slow flow, tissue hypoxemia and endothelial dysfunction. Fibrinogen is a major determinant in the formation of aggregated red blood cells. It has been suggested that the Bβ-fibrinogen –455G/A polymorphism is associated with erythrocyte hyperaggregability in men with coronary artery disease.The purpose of this study was to investigate the influence of the β-fibrinogen –455G/A polymorphism on erythrocyte aggregation in apparently healthy individuals. Plasma fibrinogen, red blood cell count, serum lipids, erythrocyte sedimentation rate, and the genotype of the Bβ-fibrinogen –455G/A polymorphism were examined in a cohort of 545 apparently healthy individuals and those with atherothrombotic risk factors. A whole blood erythrocyte aggregation test was performed by using a simple slide test and image analysis. In men, EA levels and plasma fibrinogen levels were significantly higher in subjects carrying the –455A allele compared to subjects with the –455 GG genotype.This association did not exist in women carrying the fibrinogen –455A allele.The –455GA/AA men presented significantly higher correlation between the plasma fibrinogen concentrations and EA. This observation raises the prospect of possible change in the functional properties of the –455GA/AA fibrinogen, enhancing its ability to induce EH. This study suggests that the Bβ-fibrinogen –455A allele is related to EH in men only. Putative mechanism could be hyperfibrinogenemia anda functional change in the fibrinogen molecule that alters its ability to interact with red blood cells and supports the aggregability of these cells.

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