Blood Viscosity Research Articles

Hemodynamic Characteristics of Tortuous Microvessels Using High-Fidelity Red Blood Cell Resolved Simulations

Introduction: Tortuous microvessels are characteristic of microvascular remodeling associated with numerous physiological and pathological scenarios. These vessels have unique morphology compared to straight vessels, the latter being the subject of extensive flow modeling studies over the past few decades. Three-dimensional hemodynamics in tortuous microvessels influenced by red blood cell (RBCs), however, remain largely unknown and important questions remain. Is blood viscosity influenced by vessel tortuosity? Do RBC flow dynamics cause localized hematocrit variations in tortuous vessels? How do these dynamics affect wall shear stress patterns and the near-wall cell-free layer? Previous work has connected physiological function to tortuosity1, while other recent work has shown how RBC dynamics and vessel complexity can influence hemodynamics2. Such findings drive our hypothesis that unique hemodynamic characteristics exist in tortuous microvessels compared to straight vessels. Revealing such differences and answering the above questions requires 3D RBC-resolved simulations. The objective of this work is to investigate the hemodynamic characteristics of tortuous microvessels using high-fidelity red blood cell (RBC) resolved simulations and real image data. Methods: High fidelity RBC resolved simulations were performed using a 3D immersed boundary method (IBM) based fluid dynamic solver3. A tortuous microvessel is constructed in 3D based on imaging of a rat mesenteric microvascular network post angiogenic remodeling. The diameter and length of the vessel are 20 μm and 930 μm, respectively. Simulations were performed spanning a range of physiological shear rates (SR) and overall hematocrit levels (Ht). Output simulation data is used to parametrically quantify characteristics of apparent viscosity, local hematocrit variations, time-averaged wall shear stress (TAWSS) and cell free layer (CFL) patterns due to vessel tortuosity. Data and Results: The findings show how curvature can increase apparent viscosity to different degrees based on overall Ht & SR (max 236% increase), with local variations occurring over the vessel length at sites of curvature changes (max 2.25cP change). Because of RBC flow patterns, local variations in tube hematocrit are found to occur which result in local curvature-dependent variations in the Fahraeus effect. We further characterize dependencies of the CFL and TAWSS on Ht & SR and resultant lengthwise 3D spatial variations along the vessel, and demonstrate correlation patterns between these two quantities as influenced by tortuosity. Conclusions: New findings from this work reveal significant dependency of hemodynamic parameters and spatial variations on vessel tortuosity. The results provide new information to better understand the role of vessel tortuosity in physiological and pathological processes, as well as help improve reduced-order models. NSF CBET 2309559, NIH R21HL159501, and Expanse at the San Diego Supercomputer Center per NSF Accelerate Award BIO230073. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mildronate ameliorates kidney injury and reduces inflammation in Sickle Cell Disease mice

INTRODUCTION: Sickle cell disease (SCD) is a hereditary hemoglobin disorder characterized by hemolytic anemia, vaso-occlusive crisis and chronic inflammation that affects multiple organs including kidney, liver, brain, spleen, and heart. Renal disease, the most common complication in SCD, is a progressive disease that begins in childhood as glomerular hyperfiltration, then advances to albuminuria, following by a fast decline in glomerular filtration. It may further progress to a renal failure in adults. More than 50% of SCD patients develop chronic kidney disease (CKD), and 14-18% progress to the end-stage kidney disease. Renal injury in SCD results from a cascade of events starting with chronic red blood cells sickling and hemolysis leading to increased blood viscosity, microvascular obstruction and dilation, hypoxia in the medulla, oxidative stress, and inflammation. Mildronate (meldonium) is an anti-ischemic and anti-inflammatory medication approved in Eastern Europe. HYPOTHESIS: We hypothesized that mildronate administration reduces renal medullary hypoxia and decreases oxidative stress and inflammation ameliorating renal injury in SCD mice. METHODS: The study was approved by the Howard University IACUC. Townes SCD mice, expressing human HbS, and control mice, expressing human HbA, were injected with mildronate (400 mg/kg in saline) intraperitoneally or saline as vehicle control over the course of ten days. Blood was collected and used for hematological parameters analysis. Cytokines were measured by Bio-Plex suspension array in plasma. Hypoxyprobe Biotin kit (Hypoxyprobe Inc) was used for visualization of organ hypoxia. The effect of Mildronate on systemic and renal oxidative stress was measured by malondialdehyde (MDA) using ELISA (Abcam). Urinary KIM-1 was measured by TIM-1/KIM-1 ELISA kit (R&D Systems). RESULTS: Mildornate injections did not affect hematological parameters of SCD mice including hematocrit, MCV, MCH, CMCH, erythrocytes and hemoglobin. Mildronate administration resulted in a significant reduction of the circulating pro-inflammatory cytokines IFN-γ, IL-1β and TNF-α and a trend toward reduction of IL-6, and IL-17 in SCD mice. We found higher level of hypoxia in the medulla of SCD mice compared to control mice. Mildronate injections did not reduced hypoxia in renal medulla of SCD mice. Also, mildronate injections did not change MDA levels in plasma or kidney of SCD mice. We found a significant reduction of proteinuria in SCD mice injected with mildronate compared to SCD mice injected with vehicle. Analysis of H&E-stained kidneys showed significant reduction of glomerular size and medullar congestion areas in the mildronate injected SCD mice. Urinary KIM-1 levels were reduced by mildronate administration. CONCLUSIONS: Our results demonstrate that mildronate ameliorates glomerular and tubular injury in SCD mice and reduces capillary congestion. Mildronate improves renal function, in part by reducing inflammation but not through the reduction of hypoxia or oxidative stress. In future, we plan to assess the mildronate’s impact on kidney function and vessel inflammation. This work was supported by NIH grants R01HL125005, U54MD007597, and SC1HL150685. We thank Xiaomei Niu for helping with the Bio-Plex assay. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Blood Rheology and Hemodynamics: Still Illuminating after 20 Years.

Blood Rheology and Hemodynamics: Still Illuminating after 20 Years.

Fiber Optic Assisted Optofluidic Viscometer for Biomedical Applications

Fiber Optic Assisted Optofluidic Viscometer for Biomedical Applications

On a Parameter-controlled Method for Multiple Zeros

For a parameter-controlled Newton-secant method, we investigate the complex dynamics with the stability surfaces and parameter spaces using Möbious conjugacy map applied to the form $((z-A) (z-B))^m$. The basins of attraction of test functions is illustrated according to the color palette. The nonlinear equation related to blood rheology model has been employed to show the basins of attraction.

Numerical simulation of cellular blood flow in curved micro-vessels with saccular aneurysms: Effect of curvature degree and hematocrit level.

The dynamics of cellular blood flow in curved vessels considerably differ from those in straight vessels. It is reported that clotting development is significantly affected by vessel shape irregularities. Thus, the current study aims to investigate the effect of curvature degree and hematocrit level on cellular blood flow in a curved micro-vessel with a saccular aneurysm. Accordingly, a three-dimensional numerical simulation is performed using a validated code developed for cellular blood flow problems. The obtained results show that the cell-free layer thickness is highly dependent on the curvature degree and hematocrit level, which may have a remarkable impact on the apparent viscosity of blood as well as the dynamics of other particles such as drug particulates. The near-wall region exhibits the highest degree of cell deformation, whereas the red blood cells within the aneurysm zone remain nearly undeformed. Meanwhile, the velocity of the red blood cells decreases with the increase in curvature degree, which can affect the quality of the oxygenation process. Because of the saccular aneurysm, a considerable decrease in plasma velocity is predicted. Moreover, no secondary flows are detected in the curved vessel except in the aneurysm zone. An increase in the curvature degree is expected to reduce the blood flow rate by about 10%. Furthermore, low wall shear stress values are predicted in the straight case compared to the values at the apex of the curved vessel, which may affect the structure and function of the endothelial cells of the vessel wall and, hence, increase the aneurysm rupture possibility.

Mendelian randomization study of whole blood viscosity and cardiovascular diseases.

Association between whole blood viscosity (WBV) and an increased risk of cardiovascular disease (CVD) has been reported. However, the causal relationship between WBV and CVD remains not thoroughly investigated. The aim of this study was to investigate the causal relation between WBV and CVD. Two-sample Mendelian randomization (MR) was employed, with inverse variance weighting (IVW) as the primary method, to investigate the casual relationship between WBV and CVD. The calculated WBV and medical records of 378,210 individuals participating in the UK Biobank study were divided into halves and analyzed. The means of calculated WBVs were 16.9 (standard deviation: 0.8) and 55.1 (standard deviation: 17.2) for high shear rate (HSR) and low shear rate (LSR), respectively. 37,859 (10.0%) major cardiovascular events (MACE) consisted of 23,894 (6.3%) cases of myocardial infarction (MI), 9,245 (2.4%) cases of ischemic stroke, 10,377 (2.7%) cases of revascularization, and 5,703 (1.5%) cases of coronary heart disease-related death. In the MR analysis, no evidence was found indicating a causal effect of WBV on MACE (IVW p-value for HSR = 0.81, IVW p-value for LSR = 0.47), MI (0.92, 0.83), ischemic stroke (0.52, 0.74), revascularization (0.71, 0.54), and coronary heart disease-related death (0.83, 0.70). The lack of sufficient evidence for causality persisted in other MR methods, including weighted median and MR-egger. The Mendelian randomization analysis conducted in this study does not support a causal relationship between calculated WBV and CVD.

Effects of magnesium sulfate combined with labetalol on inflammatory stress and pregnancy outcome of patients with gestational hypertension.

Gestational hypertension (GH) is a common disorder during pregnancy that can cause adverse pregnancy outcomes. In the present study, magnesium sulfate (MgSO4) combined with labetalol was used for clinical treatment. Randomized controlled trial was conducted in 100 patients with GH, documented in the Department of Obstetrics and Gynecology (Taicang TCM Hospital) grouped into the experimental (Expt) and control (Ctrl) groups (n=50 cases/group). The Ctrl group was treated with MgSO4, whereas the Expt group was treated with MgSO4 + labetalol. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the Expt group were not significantly different from those in the Ctrl group (P>0.05). By contrast, the SBP and DBP were significantly lower after treatment than those before treatment in both groups (P<0.05). Whole blood viscosity, plasma viscosity and hematocrit were significantly lower in the Expt group compared with those in the Ctrl group after treatment (P<0.05). High mobility group box-1 protein, homocysteine and serum cystatin C levels in the Expt group were also markedly lower than those in the Ctrl group after treatment (P<0.05). In the Expt group, the rate of spontaneous vaginal delivery was much higher, whereas the rates of cesarean section and postpartum hemorrhage were markedly lower than those in the Ctrl group (P<0.05). The occurrence of fetal intrauterine distress, placental abruption, neonatal asphyxia, premature birth and neonatal death were also significantly lower in the Expt group than those in the Ctrl group (P<0.05). In conclusion, MgSO4 + labetalol could improve inflammatory stress and the hemodynamics of patients with GH, and may have a marked antihypertensive effect. Thus, it may improve pregnancy outcome and reduce perinatal complications.

A bio-fabricated tesla valves and ultrasound waves-powered blood plasma viscometer.

Introduction: There is clinical evidence that the fresh blood viscosity is an important indicator in the development of vascular disorder and coagulation. However, existing clinical viscosity measurement techniques lack the ability to measure blood viscosity and replicate the in-vivo hemodynamics simultaneously. Methods: Here, we fabricate a novel digital device, called Tesla valves and ultrasound waves-powered blood plasma viscometer (TUBPV) which shows capacities in both viscosity measurement and coagulation monitoring. Results: Based on the Hagen-Poiseuille equation, viscosity analysis can be faithfully performed by a video microscopy. Tesla-like channel ensured unidirectional liquid motion with stable pressure driven that was triggered by the interaction of Tesla valve structure and ultrasound waves. In few seconds the TUBPV can generate an accurate viscosity profile on clinic fresh blood samples from the flow time evaluation. Besides, Tesla-inspired microchannels can be used in the real-time coagulation monitoring. Discussion: These results indicate that the TUBVP can serve as a point-of-care device in the ICU to evaluate the blood's viscosity and the anticoagulation treatment.

RBC aggregation, deformation and adhesion to endothelium: Role of nitric oxide derived from L-Arginine and sodium nitroprusside

Red blood cells (RBCs) are the most abundant human blood cells. RBC aggregation and deformation strongly determine blood viscosity which impacts hemorheology and microcirculation. In turn, RBC properties depend on different endogenous and exogenous factors. One such factor is nitric oxide (NO), which is mainly produced by endothelial cells (EC) from L-arginine amino acid in the circulatory system. Since the mechanisms of the RBC-endothelium interplay are not clear up to date and considering its possible clinical importance, the aims of this study are to investigate in vitro: (1) The effect of L-arginine induced NO on RBC aggregation and adhesion to endothelium; (2) the NO effect on RBC aggregation and deformation induced by L-arginine and sodium nitroprusside without the presence of endothelium in the samples. The RBC aggregation and adhesion to a monolayer of EC were studied using optical tweezers (OT). The RBC deformability and aggregation without endothelium in the samples were studied using the flow chamber method and Myrenne aggregometer. We confirmed that NO increases deformability and decreases aggregation of RBCs. We showed that the soluble guanylate cyclase pathway appears to be the only NO signaling pathway involved. In the samples with the endothelium, the “bell-shaped” dependence of RBC aggregation force on L-arginine concentration was observed, which improves our knowledge about the process of NO production by endothelium. Additionally, data related to L-arginine accumulation by endothelium were obtained: Necessity of the presence of extracellular L-arginine stated by other authors was put under question. In our study, NO decreased the RBC-endothelium adhesion, however, the tendency appeared to be weak and was not confirmed in another set of experiments. To our knowledge, this is the first attempt to measure the forces of RBC adhesion to endothelium monolayer with OT.

Mechanism of hypoxia-induced damage to the mechanical property in human erythrocytes-band 3 phosphorylation and sulfhydryl oxidation of membrane proteins.

Introduction: The integrity of the erythrocyte membrane cytoskeletal network controls the morphology, specific surface area, material exchange, and state of erythrocytes in the blood circulation. The antioxidant properties of resveratrol have been reported, but studies on the effect of resveratrol on the hypoxia-induced mechanical properties of erythrocytes are rare. Methods: In this study, the effects of different concentrations of resveratrol on the protection of red blood cell mor-phology and changes in intracellular redox levels were examined to select an appropriate concentration for further study. The Young's modulus and surface roughness of the red blood cells and blood viscosity were measured via atomic force microsco-py and a blood rheometer, respectively. Flow cytometry, free hemoglobin levels, and membrane lipid peroxidation levels were used to characterize cell membrane damage in the presence and absence of resveratrol after hypoxia. The effects of oxida-tive stress on the erythrocyte membrane proteins band 3 and spectrin were further investigated by immunofluorescent label-ing and Western blotting. Results and discussion: Resveratrol changed the surface roughness and Young's modulus of the erythrocyte mem-brane, reduced the rate of eryptosis in erythrocytes after hypoxia, and stabilized the intracellular redox level. Further data showed that resveratrol protected the erythrocyte membrane proteins band 3 and spectrin. Moreover, resistance to band 3 pro-tein tyrosine phosphorylation and sulfhydryl oxidation can protect the stability of the erythrocyte membrane skeleton net-work, thereby protecting erythrocyte deformability under hypoxia. The results of the present study may provide new insights into the roles of resveratrol in the prevention of hypoxia and as an antioxidant.

Correlation Analysis Between Echinocytosis Stages and Blood Viscosity During Oxygenator Perfusion: An In Vitro Study.

The study aimed to investigate the effect of red blood cell (RBC) morphology on oxygenator perfusion, focusing on stages of echinocytosis and their correlation with blood viscosity. A test circuit with an oxygenator and human RBC mixtures was used to induce changes in RBC shape by increasing sodium salicylate concentrations (0, 10, 20, 30, 60, and 120 mmol/L), while hematocrit, blood temperature, and anticoagulation were maintained. Blood viscosity was measured using a continuous blood viscosity monitoring system based on pressure-flow characteristics. Under a scanning electron microscope, the percentages of discocytes, echinocytes I-III, spheroechinocytes, and spherocytes were determined from approximately 400 cells per RBC sample. Early echinocytes, mainly discocytes and echinocytes I and II in the range of 0-30 mmol/L were predominant, resulting in a gradual increase in blood viscosity from 1.78 ± 0.12 to 1.94 ± 0.12 mPa s. At 60 mmol/L spherocytes emerged, and at 120 mmol/L, spheroidal RBCs constituted 50% of the population, and blood viscosity sharply rose to 2.50 ± 0.15 mPa s, indicating a 40% overall increase. In conclusion, the presence of spherocytes significantly increases blood viscosity, which may affect oxygenator perfusion.

Qilong capsule prevents myocardial ischemia/reperfusion injury by inhibiting platelet activation via the platelet CD36 signaling pathway

Ethnopharmacological relevanceQilong capsule (QC) is developed from the traditional Chinese medicine formula Buyang Huanwu Decoction, which has been clinically used to invigorate Qi and promote blood circulation to eliminate blood stasis. Myocardial ischemia‒reperfusion injury (MIRI) can be attributed to Qi deficiency and blood stasis. However, the effects of QC on MIRI remain unclear. Aim of the studyThis study aimed to investigate the protective effect and possible mechanism of QC on platelet function in MIRI rats. Materials and methodsThe left anterior descending artery of adult Sprague‒Dawley rats was ligated for 30 min and then reperfused for 120 min with or without QC treatment. Then, the whole blood viscosity, plasma viscosity, coagulation, platelet adhesion rate, platelet aggregation, and platelet release factors were evaluated. Platelet CD36 and its downstream signaling pathway-related proteins were detected by western blotting. Furthermore, the active components of QC and the molecular mechanism by which QC regulates platelet function were assessed via molecular docking, platelet aggregation tests in vitro and BLI analysis. ResultsWe found that QC significantly reduced the whole blood viscosity, plasma viscosity, platelet adhesion rate, and platelet aggregation induced by ADP or AA in rats with MIRI. The inhibition of platelet activation by QC was associated with reduced levels of β-TG, PF-4, P-selectin and PAF. Mechanistically, QC effectively attenuated the expression of platelet CD36 and thus inhibited the activation of Src, ERK5, and p38. The active components of QC apparently suppressed platelet aggregation in vitro and regulated the CD36 signaling pathway. ConclusionsQC improves MIRI-induced hemorheological disorders, which might be partly attributed to the inhibition of platelet activation via CD36-mediated platelet signaling pathways.

Whole Blood Viscosity and Thromboembolic Events in Hospitalized Patients with COVID-19: Post hoc Analysis of the ATTACC/ACTIV-4a Trial.

Whole Blood Viscosity and Thromboembolic Events in Hospitalized Patients with COVID-19: Post hoc Analysis of the ATTACC/ACTIV-4a Trial.

Effect of a single immersion in cold water below 4 °C on haemorheological properties of blood in healthy men

Cold water immersion (CWI) involves rapid cooling of the body, which, in healthy individuals, triggers a defence response to an extreme stimulus, to which the body reacts with stress. The aim of the study was to determine the effect of CWI on hemorheological blood indicators. The study group consisted of 13 young males. Blood samples were collected before and after CWI. The assessed parameters included the complete blood count, fibrinogen, hs-C-reactive protein (CRP), proteinogram, and blood rheology factors, such as erythrocyte elongation index (EI), half-time of total aggregation, and aggregation index. Additionally, the effect of reduced temperature on primary human vascular endothelium was investigated in vitro. CWI resulted in the decrease of body temperature to 31.55 ± 2.87 °C. After CWI, neutrophil count and mean corpuscular volume (MCV) were significantly increased in the study group, while lymphocyte count was significantly decreased. Significantly higher levels of total blood protein and albumin concentration were detected after the immersion. Among hemorheological characteristics, erythrocyte EIs at shear stress values ranging from 2.19 to 60.30 Pa were significantly lower after CWI. No significant changes in other rheological, morphological or biochemical parameters were observed. In vitro, human umbilical vein endothelial cells responded to 3 h of temperature decrease to 25 °C with unchanged viability, but increased recruitment of THP-1 monocytic cells and changes in cell morphology were observed. This was the first study to evaluate the effect of single CWI on rheological properties of blood in healthy young men. The results indicate that a single CWI may increase blood protein concentrations and worsen erythrocyte deformability parameters.

THE ANALYSIS OF THE FLOW OF BLOOD IN A STENOSED ARTERY THROUGH SIMULATION: A COMPARISON AMONG VARIOUS NON-NEWTONIAN MODELS

This paper focuses on the dual quality of blood, Newtonian and non-Newtonian, in particular by exploring the energy curves. Careful investigation of the dual property of blood has been made by considering two different geometries to represent a stenosed arterial segment. We present a cautious assessment of non-Newtonian blood rheology impacts in arterial stream simulations by coupling the Newtonian and non-Newtonian models. The flow of energy through the two flow dimensions is meticulously investigated using velocity (kinetic energy), pressure, and wall shear stress (pressure energy). Besides, the proper implementation of an interface boundary condition (IBC) was emphasized to ensure consistency with the flow conditions downstream of a backward-facing step. The integration of the Newtonian and non-Newtonian models adjoins the novelty of the current research. The energy curves are obtained by implementing five different non-Newtonian models to designate a suitable non-Newtonian model for blood flow investigations. The combination of the non-Newtonian models enforced in this research is novel and particular attention is paid to the energy curves obtained. The conclusion was to elect the Carreau model as a suitable non-Newtonian rheological model for the blood flow study. This study was able to finalize the fact that the coupling of Newtonian and non-Newtonian models is necessary to obtain accurate results. For the sinusoidal waveform considered for the velocity, Carreau and the Power law models yield better results, eliminating the other non-Newtonian models from the list. With a better inlet condition imposed in the form of the Fourier series for pressure and velocity, the Carreau model yields the best results.

Investigation of Zinc on hemorheological parameters in a rat model of diabetes

Diabetes mellitus (DM) is a complex, chronic metabolic disorder characterized by impaired regulation of blood glucose levels. Zinc (Zn) is an essential trace elements that plays a role in various physiological processes within the body, including those related to diabetes. The current study was investigated the effect of Zn supplementation on hemorheological parameters in a rat model of DM. After induction of DM, 32 male Wistar albino rats were divided into four groups: control, Zn, DM, and Zn+DM. Whole blood viscosity (WBV) was determined by using digital cone and plate viscometer and plasma viscosity (PV) was determined by a Coulter Harkness capillary viscometer. The rats in the DM Group showed a decrease in both Zn levels and body weight, as well as an increase in glucose levels when compared to the control group. Diabetic rats supplemented with Zn displayed lower blood glucose levels and higher concentrations of Zn compared to the DM Group. The higher PV and lower hematocrit level were measured in DM Group than control group and lower PV, higher hematocrit level were measured in Zn+DM group than DM Group. The WBV was measured at four different shear rates (57.6–115.2 - 172.8–230.4 s −1). A statistically significant increase was observed in the DM group compared to the control group. Additionally, a statistically significant decrease was observed in the Zn+DM Group compared to the DM Group at a shear rate of 230.4 s−1. Erythrocyte rigidity index (Tk) and oxygen delivery index (ODI) were computed under conditions of high shear rate. The rats in the DM group exhibited a reduction in ODI and an elevation in Tk in comparison to the control group. Conversely, the diabetic rats supplemented with Zn exhibited decreased Tk and increased ODI compared to the DM Group. Zn supplementation seems to have a potential beneficial effect for protecting adverse affect of diabetes on hemorheogical parameters and for maintaining vascular health.

On viscoelastic blood in a locally narrow artery with magnetic field: application of distributed-order time fractional Maxwell model

Purpose. The study of hemorheology of heterogeneous vessels is of importance for the therapy of cardiovascular diseases. The present paper aims to investigate the effects of the height parameter of the stenosis, the Reynolds number, the relaxation time and the Hartmann number on the blood flow by applying distributed order time fractional Maxwell model. Methodology. Distributed order time fractional Maxwell constitutive fluid model is used to simulate viscoelastic blood flowing in a narrowing blood vessel with uniform magnetic field. The continuity and momentum equations are established in two-dimensional cylindrical coordinate system for calculation. With vorticity-stream function method, the finite difference technique, combined with the fractional derivative L1 interpolation approximation, is utilized to obtain numerical solutions of velocity and wall shear stress. The effectiveness of the numerical method is verified. Outcomes. It reveals the choice of relaxation time in the governing equation has an influence on the results. The numerical results show that an appropriate increase of Reynolds number can reduce the possibility of vessel damage. Furthermore, when the height parameter of the stenosis increases, the damage to the vessel wall is getting serious. Besides, the wall shear stress along the blood vessel increases with the increase of the magnetic field, but the wall shear stress in the narrowest part of the blood vessel changes little.

Clinical study on treatment of cervical spondylotic radiculopathy (Qi stagnation and blood stasis syndrome) with Gao's nape needle and Shentong Zhuyu decoction.

Cervical spondylotic radiculopathy is currently one of the common orthopedic diseases, mainly characterized by neck pain, stiffness, limited mobility, and related symptoms of nerve root compression, which seriously troubles people's work and life. Ninety cases of cervical spondylotic radiculopathy (Qi stagnation and blood stasis syndrome) were randomly divided into treatment group and control group, 45 cases in each group. The control group was treated with western medicine (nerve nutrition, pain relief, and circulation improvement drugs), and the treatment group was treated with Gao's nape needle combined with modified Shentong Zhuyu decoction on the basis of the control group. Before and after 2 weeks, TCM syndrome score, TCM curative effect, visual analogue scale score, numbness score, neck disability index score, related serum inflammatory factors (interleukin-10 [IL-10], interleukin-6 [IL-6], tumor necrosis factor-α [TNF-α]), related hemorheological indexes (plasma viscosity, high shear whole blood viscosity, low shear whole blood viscosity level) were used as evaluation indexes to evaluate the effect. After treatment, the total effective rate of the treatment group was 91.11%, which was better than that of the control group (78.78%), and the TCM syndrome scores of the 2 groups were decreased, the treatment group was better than that of the control group, and the differences were statistically significant (P < .05). After treatment, the visual analogue scale score, numbness score, and neck disability index score were decreased in both groups, and the decrease in the treatment group was more significant than that in the control group, and the differences were statistically significant (P < .05). After treatment, the related serum inflammatory factors (IL-10, IL-6, TNF-α) and related hemorheological indexes (plasma viscosity, high-shear whole blood viscosity, low-shear whole blood viscosity) were decreased in both groups, and the decrease in the treatment group was more significant than that in the control group, and the differences were statistically significant (P < .05). The treatment of cervical spondylotic radiculopathy (Qi stagnation and blood stasis syndrome) with Gao's nape needle and modified Shentong Zhuyu decoction can improve the curative effect of traditional Chinese medicine, improve the related discomfort symptoms (neck tenderness, adverse activity, numbness, etc), improve the neck function, reduce IL-10, IL-6, TNF-α, and other related serum inflammatory factors, and improve hemorheological indicators.

Redefining hyperviscosity in acute leukemia: Potential implications for red cell transfusions in the microvasculature.

Hyperleukocytosis is an emergency of acute leukemia leading to blood hyperviscosity, potentially resulting in life-threatening microvascular obstruction, or leukostasis. Due to the high number of red cells in the circulation, hematocrit/hemoglobin levels (Hct/Hgb) are major drivers of blood viscosity, but how Hct/Hgb mediates hyperviscosity in acute leukemia remains unknown. In vivo hemorheological studies are difficult to conduct and interpret due to issues related to visualizing and manipulating the microvasculature. To that end, a multi-vessel microfluidic device recapitulating the size-scale and geometry of the microvasculature was designed to investigate how Hct/Hgb interacts with acute leukemia to induce "in vitro" leukostasis. Using patient samples and cell lines, the degree of leukostasis was different among leukemia immunophenotypes with respect to white blood cell (WBC) count and Hct/Hgb. Among lymphoid immunophenotypes, severe anemia is protective against in vitro leukostasis and Hct/Hgb thresholds became apparent above which in vitro leukostasis significantly increased, to a greater extent with B-cell acute lymphoblastic leukemia (ALL) versus T-cell ALL. In vitro leukostasis in acute myeloid leukemia was primarily driven by WBC with little interaction with Hct/Hgb. This sets the stage for prospective clinical studies assessing how red cell transfusion may affect leukostasis risk in immunophenotypically different acute leukemia patients.