Rheological Characteristics Of Blood Research Articles

Influence of thrombosis, stenosis and catheter on rheological characteristics of blood: a systematic review

Influence of thrombosis, stenosis and catheter on rheological characteristics of blood: a systematic review

Dimensional and Physiological-Biochemical Parameters of Erythrocytes and Gill and Heart Indices in Some Benthic Fish of the Black Sea Coast of the Southeastern Crimea

The dimensional and physiological-biochemical parameters of erythrocytes, as well as the gill and heart indices were studied in five species of marine benthic fish. The black scorpionfish Scorpaena porcus Linnaeus, 1758 and the shore rockling Gaidropsarus mediterraneus Linnaeus, 1758 differed from the other species in a larger mass of the heart and gill apparatus, which indicates more efficient transport capabilities of the circulatory system of these fish. The linear size characteristics of erythrocytes of a cartilaginous fish, the thornback ray Raja clavata Linnaeus, 1758, were 1.5–2 times higher than those of erythrocytes of S. porcus, which were the largest among the studied teleosts. The sizes of erythrocytes of three other teleost species differed insignificantly. The amount of hemoglobin per unit surface area of erythrocyte, which reflects the efficiency of hemoglobin saturation with oxygen, insignificantly varied (0.05 to 0.071 pg/mm2) among the bony fish stu-died. In contrast, in the thornback ray this parameter was 2.7–3.8 times lower. The intracellular glycogen concentration, which characterizes the degree to which the erythrocyte is independent of glycemic fluctuations, was highest in cells of S. porcus (305.2 ± 35.1 mg %), while it was lowest in erythrocytes of the thornback ray R. clavata (142.8 ± 15.1 mg %). The ecto-ATPase activity was higher in large erythrocytes of S. porcus, R. clavata, and Uranoscopus scaber (4.8, 3.1, and 1.6 µmol Pin/min/mL of erythrocytes, respectively) than in smaller erythrocytes of Crenilabrus tinca and Gaidropsarus mediterraneus (0.5 and 0.4, µmol Pin/min/mL of erythrocytes, respectively). This confirms the assumption that erythrocytes use the thermal energy from hydrolysis of extracellular ATP to “warm up” their own membrane, which leads to the change in the rheological characteristics of blood in the capillary blood flow.

Simulation of Blood as Fluid: A Review From Rheological Aspects.

Blood flow in the human vascular system is a complex to understand example of fluid dynamics in a closed conduit. Any irregularities in the hemodynamics may lead to lethal cardiovascular disease like heart attack, heart failure and ischemia. Numerical simulation of hemodynamics in the blood vessel can facilitate a thorough understanding of blood flow and its interaction with the adjacent vessel wall. A good simulation approach for blood flow can be helpful in early prediction and diagnosis of the mentioned disease. The simulation outcomes may also provide decision support for surgical planning and medical implants. This study reports an extensive review of various approaches adopted to analyze the influence of blood rheological characteristics in a different class of blood vessels. In particular, emphasis was given on the identification of best possible rheological model to effectively solve the hemodynamics inside different blood vessels. The performance capability of different rheological models was discussed for different classes and conditions of vessels and the best/poor performing models are listed out. The Carreau, Casson and generalized power-law models were appeared to be superior for solving the blood flow at all shear rates. In contrast, power law, Walburn-Scheck and Herchel-Bulkley model lacks behind in the purpose.

Variability of heart rhythm in patients with myocardial infarction with Q wave with standard therapy and nutritive support with organic selenium

Aim. Assessment if the interrelation of the levels of selenium, parameters of heart rate variability (HRV), biochemical and rheological characteristics of blood in patients with Q-myocardial infarction (Q-MI) taking standard medicinal therapy and dietary correction with organic selenium in different stages of the disease.
 Materials and Methods. An open comparative clinical study was conducted with involvement of 90 patients (the average age 58.31.4, of them 71 men and 19 women) diagnosed with acute coronary syndrome with elevation of Q-segment with outcome into Q-MI. The patients were divided to two comparable groups: control group that received standard therapy, and the main group that additionally received dietary product enriched with organic selenium. In acute, subacute and cicatrization stages, the dynamic series of RR intervals were recorded and mathematically analyzed on Varicard 2.51 complex, some biochemical parameters of blood, selenium status, rheological properties of blood were assessed.
 Results. In the stage of hospital treatment, reduction of the heart rate (from 68.81.7 to 64.01.3 beat/min; p0.05) was recorded in the main group. The initial level of SDNN in both groups was within the critical range (25.01.3 msec), and stress index (SI) several time exceeded the norm (1356.2390.6 conv.un.); by the end of the observation both parameters did not achieve normal values in both groups. The coefficient of variation (CV) stayed below normal values throughout the whole treatment period, although in the dynamics it showed some tendency to growth. The spectrum power of the curve enveloping the dynamic series of RR intervals (HF) almost twice increased in the control group (р0.05). Correlation analysis of the interrelation of biochemical parameters of blood, coagulogram and selenium of blood serum with different parameters of mathematical analysis of the heart rhythm revealed interrelations of different levels and direction.
 Conclusion. Use of dietary product rich in selenium having a positive effect on the trophotropic functions of an organism, in complex with standard therapy, reduces tension of adaptation mechanisms and enhances adaptation potential of an organism that improves the prognosis and reduces risks.

P1798Thrombocytes functional state and rheological characteristics of blood in patients with chronic heart failure due to coronary artery disease combined with chronic obstructive pulmonary disease

P1798Thrombocytes functional state and rheological characteristics of blood in patients with chronic heart failure due to coronary artery disease combined with chronic obstructive pulmonary disease

Numerical simulation of non-Newtonian models effect on hemodynamic factors of pulsatile blood flow in elastic stenosed artery

Atherosclerosis develops due to different hemodynamic factors, among which time-averaged Wall shear stress (mean WSS) and Oscillatory shear index (OSI) are two of the most important. These two factors not only depend on flow geometry, but are also influenced by rheological characteristics of blood. Since analytical solutions are limited to simple problems and since experimental tests are costly and time consuming, CFD solutions been prominently and effectively used to solve such problems. We conducted a numerical study via ADINA 8.8 software on the non-Newtonian pulsatile flow of blood through an elastic blood artery with single and consecutive stenosis. The studied stenosis cross sectional area was 70 % that of the unstenosed artery. The single stenosis results were compared with the consecutive stenosis results. The five non-Newtonian flow models, the Carreau model, the Carreau-Yasuda model, the modified Casson model, the power-law model, and the generalized power-law model, were used to model the non-Newtonian blood flow. The obtained results showed that increasing the number of stenoses would lead to reduced length of the oscillatory area after the first stenosis, thus forming another oscillatory area with a larger length after the second stenosis. Thus, a consecutive stenosis would develop a larger disease prone area. Upon examining the mean WSS and OSI, we found that, as compared with the other models, the modified Casson model and the power-law model produced predictions for the most extent of damage to endothelial cells and the most disease prone areas, respectively.

Non-Newtonian effects of blood on LDL transport inside the arterial lumen and across multi-layered arterial wall with and without stenosis

Blood non-Newtonian behavior on low-density lipoproteins (LDL) accumulation is analyzed numerically, while fluid-multilayered arteries are adopted for nonstenotic and 30%–60% symmetrical stenosed models. Present model considers non-Newtonian effects inside the lumen and within arterial layers simultaneously, which has not been examined in previous studies. Navier–Stokes equations are solved along with the mass transport convection–diffusion equations and Darcy’s model for species transport inside the luminal flow and across wall layers, respectively. Carreau model for the luminal flow and the modified Darcy equation for the power-law fluid within arterial layers are employed to model blood rheological characteristics, appropriately. Results indicate that in large arteries with relatively high Reynolds number Newtonian model estimates LDL concentration patterns well enough, however, this model seriously incompetent for regions with low WSS. Moreover, Newtonian model for plasma underestimates LDL concentration especially on luminal surface and across arterial wall. Therefore, applying non-Newtonian model seems essential for reaching to a more accurate estimation of LDL distribution in the artery. Finally, blood flow inside constricted arteries demonstrates that LDL concentration patterns along the stenoses inside the luminal flow and across arterial layers are strongly influenced as compared to the nonstenotic arteries. Additionally, among four stenosis severity grades, 40% stenosis is prone to more LDL accumulation along the post-stenotic regions.

Effects of rhythmic exercise performed to music on the rheological properties of blood in women over 60 years of age

The aim of this study was to analyze the effects of motor rehabilitation, in the form of rhythmic exercise to music, on the rheological characteristics of blood in older women. The study included 30 women (65-80 years of age), and the control group was comprised of 10 women of corresponding age. Women from the experimental group were subjected to a five-month rehabilitation program, in the form of rhythmic exercise performed to music (three 30-minute sessions per week); women from the control group were not involved in any regular physical activity. Blood samples from all the women were examined for hematological, rheological, and biochemical parameters prior to the study and five months thereafter. The rehabilitation program was reflected by a significant improvement of erythrocyte count and hematocrit. Furthermore, an improvement of erythrocyte deformability was observed by lower shear stress levels, while no significant changes were noted by the higher shear stress values. The rehabilitation resulted in a marked decrease of the aggregation amplitude while no significant changes were observed in aggregation index and total aggregation half-time. Additionally, the training regimen was reflected by a significant increase in the plasma viscosity, while no significant changes in fibrinogen levels were noted.

Obstructions in Vascular Networks: Relation Between Network Morphology and Blood Supply.

We relate vascular network structure to hemodynamics after vessel obstructions. We consider tree-like networks with a viscoelastic fluid with the rheological characteristics of blood. We analyze the network hemodynamic response, which is a function of the frequencies involved in the driving, and a measurement of the resistance to flow. This response function allows the study of the hemodynamics of the system, without the knowledge of a particular pressure gradient. We find analytical expressions for the network response, which explicitly show the roles played by the network structure, the degree of obstruction, and the geometrical place in which obstructions occur. Notably, we find that the sequence of resistances of the network without occlusions strongly determines the tendencies that the response function has with the anatomical place where obstructions are located. We identify anatomical sites in a network that are critical for its overall capacity to supply blood to a tissue after obstructions. We demonstrate that relatively small obstructions in such critical sites are able to cause a much larger decrease on flow than larger obstructions placed in non-critical sites. Our results indicate that, to a large extent, the response of the network is determined locally. That is, it depends on the structure that the vasculature has around the place where occlusions are found. This result is manifest in a network that follows Murray’s law, which is in reasonable agreement with several mammalian vasculatures. For this one, occlusions in early generation vessels have a radically different effect than occlusions in late generation vessels occluding the same percentage of area available to flow. This locality implies that whenever there is a tissue irrigated by a tree-like in vivo vasculature, our model is able to interpret how important obstructions are for the irrigation of such tissue.

Biomechanical model of cerebral vascular dynamics and their effect on CSF dynamics

With advancing age venous wall thickness increases going along with a loss of elastic properties, the arterioles curl and capillary density decreases leading to a reduction of cross sectional area [1]. Even in healthy individuals these changes influence vascular and CSF dynamics, as a reduction of total cerebral blood flow, aqueduct and cervical stroke volume are reported [2]. In NPH these dynamics seem to be altered in a different way, as aqueduct stroke volume [2] and ICP amplitude are increased and arteriovenous delay is drastically reduced compared to normal aging [3]. However it is not clear in what way the described vascular alterations influence the pressure propagation inside the vessels and impact CSF dynamics. So far no biomechanical model exists that investigates the influence of macroscopic and microscopic changes of cerebral blood vessels. That is why we put a model up for discussion that simulates vascular pressure propagation and enables the investigation of altered vascular properties in the context of NPH. A Matlab Simulink model was developed reproducing each vessel section by a distensible compartment. Therefore the cerebral vascular tree was divided into 13 sections from carotid artery to venous sinuses and the pulsatile carotid artery and sinus pressure were inputted as Fourier series. The cross sectional area was varied according to literature data and flow resistance was implemented taking into account the rheological characteristics of blood. The Windkessel function and relaxation properties of vascular walls were integrated by a Voigt model, enabling the variation of wall properties for each section individually. Due to the distensible vessel walls each section interacts with the CSF compartment and autoregulation was implemented by a simple proportional controller. After parameterisation mean pressure and pressure amplitude in the vessel sections showed good accordance with literature values [4]. We have proposed a model of vascular dynamics that is able to identify the impact of altered vascular wall properties and structural changes. Furthermore the effect of different arterial and venous input pressure profiles can be analysed. These parameter analyses are part of our ongoing research.

Development of dual micro-PIV system for simultaneous velocity measurements: optical arrangement techniques and application to blood flow measurements

Blood rheological characteristics can significantly vary with the motion of red blood cells (RBCs) in plasma. Moreover, RBCs show a complicated behavior in micro vessels. Thus, the determination of either plasma or blood cell velocity distribution has been the primary objective in blood flow analysis. However, the conditions during blood flow analyses are different from the actual physiological conditions, wherein the motion of the two distinct blood phases simultaneously occurs. In this study, we used an in vitro micro-particle image velocimetry, which is a reliable velocity field measurement technique, to evaluate the velocity distribution of plasma and blood cells simultaneously. Blood flow through a rectangular microchannel was determined using special optical filter arrangements and by assuming two different hematocrit values. Using the proposed technique, the averaged parabolic velocity profiles for the RBCs and plasma were successfully obtained and compared. The developed simultaneous measurement technique can be used to predict blood cell and plasma behaviors simultaneously with high accuracy under given clinical conditions.

Flow and anastomosis in vascular networks

We analyze the effect that the geometrical place of anastomosis in the circulatory tree has on blood flow. We introduce an idealized model that consists of a symmetric network for the arterial and venous vascular trees. We consider that the network contains a viscoelastic fluid with the rheological characteristics of blood, and analyze the network hydrodynamic response to a time-dependent periodic pressure gradient. This response is a measurement of the resistance to flow: the larger the response, the smaller the resistance to flow. We find that for networks whose vessels have the same radius and length, the outer the level of the branching tree in which anastomosis occurs, the larger the network response. Moreover, when anastomosis is incorporated in the form of bypasses that bridge vessels at different bifurcation levels, the further apart are the levels bridged by the bypass, the larger the response is. Furthermore, we apply the model to the available information for the dog circulatory system and find that the effect that anastomosis causes at different bifurcation levels is strongly determined by the structure of the underlying network without anastomosis. We rationalize our results by introducing two idealized models and approximated analytical expressions that allow us to argue that, to a large extent, the response of the network with anastomosis is determined locally. We have also considered the influence of the myogenic effect. This one has a large quantitative impact on the network response. However, the qualitative behavior of the network response with anastomosis is the same with or without consideration of the myogenic effect. That is, it depends on the structure that the underlying vessel network has in a small neighborhood around the place where anastomosis occurs. This implies that whenever there is an underlying tree-like network in an in vivo vasculature, our model is able to interpret the anastomotic effect.

Effect of levamisole on biological behavior of red blood cells after fracture

Objective To investigate the influence of levamisole (LMS) on the biological behavior of red blood cells (RBC) after fracture, in order to suggest a new strategy for prevention and therapy of traumatic deep venous thrombosis (DVT) . Methods Thirty male rabbits were divided randomly into 2 equal groups, control group A and experimental group B. After anesthesia, fractures were created 3 cm below the entotrochanter and then fixed with plates and screws in both groups. Blood samples were harvested from the 2 groups to analyze blood rheological characteristics respectively at 30 min before operation, 30 min, 1, 4 and 7 days after operation. Malondialdehyde (MDA), rigid index, accumulation index and distortion index, C3b receptor rate (RC3bRR), circulating immune complexes rate (RICR) and natural tumor erythrocyte rosette rate (NTERR) of RBCs were measured. Results RBC immunity: The rates of RC3BRR and NTERR in group B were higher than in the control group (group A) (P < 0.05) at 30 min, 1 and 4 days after operation. However, the rate of RICR was higher in group A than in group B (P < 0.05). There were significant dif-ferences between pre- and post-operation in group A, but not in group B. RBC lipid peroxidation: The post-operative MDA values of RBCs at 30 min, 1 and 4 days in both groups were higher than the preoperative one. The differences were statistically significant (P < 0.05) in group A, but not in group B. The MDA was lower in group B than in group A (P < 0.05). Conclusions Trauma can weaken the RBC immune function, increase the lipid perexidation, and worsen the blood rheological property. LMS can obviously improve the biological behavior of RBC, suggesting it may be useful in prevention and therapy of DVT after fracture. Key words: Immunologic factors; Erythrocyte; Venous thrombosis (DVT); Wounds and traumas; Fracture

Steady laminar flow of blood through successive restrictions in circular conduits of small diameter

In this paper, numerical results on steady laminar flow of blood through an artery having two successive identical axisymmetric restrictions are presented, at varying degrees of restrictions. Physically, such a flow has features in common with steady blood flow through an artery with multiple stenoses. Additionally, results are presented for the blood flow through an artery in the presence of a single restriction, for comparison. The artery has been modelled as a tube with a rigid wall. The rheological characteristics of blood have been assumed both as Newtonian and non-Newtonian. Three different non-Newtonian models of blood — power law, Quemada, and Carreau—Yasuda models — have been considered in the analysis. The haemodynamic effects of the restrictions on the axial velocity distribution, recirculation zones formed downstream to the restrictions, the wall shear stress, and the pressure drop in the artery have been analysed. The irreversible pressure loss coefficient is calculated from the pressure drop and its variation with the degree of stenosis is obtained.

Changes of Rheological and Hematological Parameters in Rats of Wistar and SHR Lines at Single and Multiple Tredmill Running

In experiments on rats of the Wistar line and on spontaneously hypertensive animals of the SHR line, a complex study was performed of rheological (deformability and aggregation properties) and hematological parameters of erythrocytes at the single (40 min) and multiple (20–30 min for 7 and 14 days) exercise load (a forced tredmill running at a rate of 14 m/min). It has been shown that rats of both lines respond to the single, sufficiently light exercise load by a manifestation of stress-reaction. After the repeated exercise load, all stress-induced changes were leveled and replaced by adaptation to this action in Wistar rats, but not in the SHR line rats. The hypertensive rats were characterized by a greater fatigue and refusal of the tredmill running; therefore, this load to them had to be shortened to 20 min. For the 1st week of running, no statistically significant differences in the studied parameters were found between rats of the Wistar and SHR lines; however, by the 14th day of training, substantial differences between these lines were noticed: the Wistar rats were easily adapted to the tredmill running, whereas the SHR animals completely refused to run. At the single running, the stress-polycythemia, an increased hematocrit, a decreased hemoglobin concentration per erythrocyte, an increased plasma corticosterone level, and changes of blood rheological characteristics were shown, the erythrocyte deformability and the spontaneous aggregation rate under the stress conditions being in the direct positive correlational dependence that was absent in control. The Wistar rat training to the exercise load for 14 days led to normalization of the parameters, which indicates a favorable effect of trainings on the animal health state.

Relationship between Electrolyte Balance and Hemorheological Characteristics in Athletes

The relationships between some parameters of electrolyte balance and blood rheological characteristics are studied in healthy young subjects and athletes. In the total group of subjects (n = 41), the viscosity of whole blood is positively correlated with the sodium ion concentration and negatively correlated with the inorganic phosphorus concentration. The blood concentration of inorganic phosphorus is increased in the athletes and is positively correlated with deformability of erythrocytes and negatively with their aggregability. The serum concentration of potassium ions is related, via its relationship with MCV, to erythrocyte deformability. In the athletes (n = 27), the erythrocyte deformability is decreased and the blood concentrations of iron and magnesium are increased. It is conceivable that the state of electrolyte balance in healthy young humans is related to their blood rheology.

Haematological and rheological characteristics of blood in seven marine mammal species: physiological implications for diving behaviour

The haeniatological and rheological characteristics of blood from seven marine mammal species have been examined to determine the relationship between increased haematocrit. which is correlated with the ability to increase aerobic dive limits. and blood viscosity. The species examined reflect adaptations to a variety of marine niches ranging from coastal to pelagic to iceedge environments. and exhibit a wide range of diving behaviours. Average haematocrits ranged from43–45% in bottlenose dolphins. killer whales and California sea lions to more than 60% in the deeper diving species (beluga whales and northern elephant seals). Whole blood viscosity () increased exponentially with haematocrit (= 0.96*e0‐0335*Hct). representin a two‐fold increase from 4.1 cP for killer whale blood to 8.9 cP for northern elephant seal. There was no apparent compensatory mechanism to reduce viscosity at any shear rate. The optimal haematocrit for oxygen transport was calculated to be40–50% for all species tested. The species with lower haematocrits were within optimal values for oxygen transport. while the two species with the highest haematocrits (beluga whales and northern elephant seals) were above predicted optimal oxygen transport values. On the basis of comparisons of the diving behaviour of these seven species, we suggest that marine mammal species with the greatest adaptation for increased oxygen stores via increased haematocrit have the capacity for deep, long‐duration dives, but a limited oxygen transport capacity. We predict that this compromise precludes fast sustainable swimming behaviour in these species.

Rheological characteristics of blood through the menstrual cycle.

Rheological characteristics of blood through the menstrual cycle.

Diffusion of oxygen and carbon dioxide through blood flowing in a channel

The numerical solutions of diffusion equations have been obtained for the cases of oxygen and carbon dioxide diffusing through blood flowing between two porous parallel planes. It is assumed that at the entrance to the channel the concentration profiles are uniform and the velocity profile is fully developed. The rheological characteristics of blood are described by the Casson equation. The computations have been made employing the explicit finite-difference forward-marching procedure. The results have been obtained for a wide range of yield numbers, inlet partial pressures, pH, membrane resistances and haemoglobin concentrations.