Rheological Properties Of Blood Research Articles

Modeling of nanoblood flow in an artery in presence of eco-friendly and biocompatible hybrid nanoparticles

Transferring biological fluid through arteries is a topic that has garnered serious interest in recent times, especially when it pertains to applications such as drug delivery. In our body, arteries serve as the primary conduits for blood flow and this study aims to model the blood flow in this situation. The working fluid is essentially pure blood, which acts as a base fluid, supplemented with nanoparticles of Titanium Dioxide (TiO2) and Gold (Au). Nanoparticles could change the thermal and rheological properties of blood which might be particularly advantageous for ensuring smoother flow or optimal distribution of drug molecules within the bloodstream. In the present work, a porous channel is considered with parallel walls that exhibit varying permeability on boundaries. Such a design enables the nanoblood to enter and exit the channel, mimicking certain natural processes like transvascular fluid exchange. Additionally, the variable height of the channel that expands and squeezes uniformly could be reminiscent of the pulsatile nature of blood flow seen in our arteries due to heartbeats. To understand the dynamics of this hybrid nanoblood flow, the governing equations are converted into a set of nonlinear ordinary differential equations using the similarity transformation approach. For solving these transformed equations, the research harnesses the BVP4C built-in function in MATLAB software. Through this computational approach, the research provides insights into the velocity and temperature profile of the fluid, the distribution of normal pressure, wall shear stress, and the Nusselt number concerning various parameters. The findings of the present study can be significant and useful in biological sciences and technologies and the detailed results are presented completely in the article’s body.

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.

Differential approach to preoperative preparations for diffuse purulent peritonitis in children

BACKGROUND: Diffuse purulent peritonitis is the most severe complication of abdominal surgical pathology accompanied by the development of serious metabolic disorders, and its elimination is a preoperative task.
 AIM: This study aimed to compare traditional preoperative preparations using a new scheme that provides a differential approach considering the stage of peritonitis, degree of endotoxicosis, child’s age, and succinate administration.
 MATERIALS AND METHODS: An analysis of the results of treatment of patients aged 1–14 years (average age 7.9 ± 3.9 years) with diffuse purulent peritonitis of various etiologies who were treated from 2006 to 2022 in the children’s surgical department of the V.D. Seredavin Samara Regional Hospital, Samara. The patients were divided into two groups. The main group included 237 patients who underwent preoperative preparation according to the proposed scheme (depending on age, peritonitis stage, and degree of endotoxemia) lasting at least 4–6 h. In addition, for intracorporeal detoxification, the antihypoxant meglumine sodium succinate was used. The control group comprised 102 children who received traditional therapy according to generally accepted approaches and national guidelines for pediatric surgery lasting 2–3 h. Changes in hemodynamic parameters, electrolytes, hematocrit, platelets, and blood gases were comprehensively examined.
 RESULTS: After preoperative preparation, a statistically significant improvement in hemodynamic parameters was observed in the main group compared with that in the control group; the indicators were close to normal values. The dynamics of hematological parameters indicated more pronounced hemodilution in patients of the main group of all ages, which proves a significant improvement in the rheological properties of blood. Electrolyte and blood gas indicators did not reach the indicators of healthy children in any groups; however, in the main group, they were closer to normal. Complications of varying severity in the main group occurred in 21 children (8.8% ± 1.4%; p 0.001), whereas in the control group, they were diagnosed in 47 patients (46.0% ± 4.6%). A statistically significant reduction in the length of stay of patients in the intensive care unit after surgery was noted in 80% of children in the main group.
 CONCLUSIONS: The proposed scheme of preoperative preparation based on a differential approach using the antihypoxant meglumine sodium demonstrated greater effectiveness than traditional treatment. The composition, volume, and duration of preoperative preparation are dependent on the state of homeostasis and the age of the patient.

Clinical and morphological features of Osler-Weber-Randu disease with signs of visceral injury

Randu-Osler-Weber disease or hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by dilated capillaries and veins, which are usually localized on the skin and mucous membranes of the oral cavity, as well as in the respiratory, urinary and digestive tracts. The anatomical basis of the disease is damage to blood vessels with degeneration and hypoplasia of the muscle and elastic layers, resulting in focal thinning of the vessel walls with further expansion of their lumen. Violation of angiogenesis persists throughout the patient's life, and is manifested by the formation of aneurysms, telangiectasias, and arteriovenous shunts. The average life expectancy of patients with burdened heredity is 63.2 years. The peak of mortality occurs at the age of 50, which is mainly associated with acute complications of the disease. However, among people suffering from Randu-Osler-Weber disease there are also long-lived people who die at the age of 70-79 years, and the cause of death is the complication of the main disease and the addition of chronic diseases. The purpose of this article is to consider in more detail possible manifestations and complications, methods of treatment of Randu-Osler-Weber disease for timely recognition of the disease and provision of timely medical assistance. This article describes a case of an abdominal form of hereditary hemorrhagic telangiectasia in an 82-year-old patient. The results of the postmortem pathomorphological examination of damaged tissues due to Randu-Osler-Weber disease are presented. During the study of micropreparations of the mucous lip, small intestine, mesentery of the small intestine and liver, groups of vessels were found, the wall of which is thinned in places and thickened in places, in the wall of these vessels there is a decrease or complete absence of muscle and elastic fibers, only endothelium is present, surrounded by loose connective tissue, postcapillary venules expand and anastomose with arterioles. In the lumen of these falsely developed vessels, mixed thrombi are determined. An elderly patient suffered from a combined pathology: hereditary hemorrhagic telangiectasia with arterio-venous malformations in the liver, heart, mesentery, small intestine, and coronary heart disease. These processes were complicated by the development of congestive heart failure, which disturbed the hemodynamic and rheological properties of blood and contributed to the occurrence of thrombosis of arterio-venous malformations in the mesentery and the wall of the small intestine. In the following, necrosis of the loops of the small intestine occurred with the development of diffuse purulent-fibrinous peritonitis and endogenous intoxication. Patients with hereditary hemorrhagic telangiectasia have a higher risk of bleeding and neurological complications, including anemia, cerebral abscess, stroke, venous thrombosis, and heart failure, because of late diagnosis of this hereditary disease. Early diagnosis is based on clinical data and careful collection of family history. In 90% of patients under the age of 40, the diagnosis of hereditary hemorrhagic telangiectasia can be established using the Curaçao criteria. This disease brings a significant amount of suffering in everyday life for both patients and their families, and requires significant attention of a multidisciplinary team of doctors at every stage of medical care.

MORPHO-FUNCTIONAL PROPERTIES OF ERYTHROCYTES AS A MARKER OF THE PROGRESS OF KIDNEY INJURIES IN PATIENTS WHO HAD CORONAVIRUS DISEASE

Pathology of the morpho-functional state of erythrocytes affects the rheological properties of blood and various regulatory processes that ensure microcirculation in the kidneys. Changes in the morpho-functional state of erythrocytes are the cause of pathological effects on the membranes and receptors of kidney cells. It leads to adverse disorders of vital activity and functioning of the kidneys.Aim. The paper aims to investigate the morpho-functional state of erythrocytes in patients with kidney damage who were sick with COVID-19. Material and methods. 75 patients aged 45-65 years with kidney damage who suffered from moderate COVID 8-12 months ago were examined. Research groups and control groups were formed (patients with appropriate nosology who did not suffer from COVID): I – glomerulonephritis; II – pyelonephritis; ІІІ – diabetic nephropathy of the 4th century. All patients had a protocol examination of nephrological patients, and we also examined the morpho-functional properties of erythrocytes (the deformability index of erythrocytes, peroxide hemolysis of erythrocytes and the relative viscosity of the erythrocyte suspension using filtration methods.Results. Changes in the morpho-functional properties of erythrocytes may indicate the progressive course of kidney diseases in patients who have undergone COVID. It manifested by a decrease in the deformability index of erythrocytes, by more than 40% in patients with glomerulonephritis and twice in patients with diabetic nephropathy, as well as a probable increase in the relative viscosity of the erythrocyte suspension, which was 2 times higher in the group with glomerulonephritis and 3 times higher in the group with diabetic nephropathy compared with pyelonephritis. An inverse correlation between daily proteinuria and the index of deformability of erythrocytes in patients with chronic kidney disease (CKD) after COVID (r=-0.59) (р=0.041), as well as a direct correlation between peroxide hemolysis of erythrocytes and daily proteinuria (r=0.68) ( p=0.038) and between the relative viscosity of the erythrocyte suspension with daily proteinuria (r=0.76) (p=0.035) were detected.Conclusions. Changes in the morpho-functional properties of erythrocytes were more profound in patients with diabetic nephropathy and glomerulonephritis after experiencing COVID than in patients with pyelonephritis. A correlation was found between indicators of morpho-functional properties of erythrocytes and daily proteinuria. Indicators of the morpho-functional properties of erythrocytes can be markers of the progression of CKD in patients who have experienced moderate COVID.

DENTAL STATUS OF PATIENTS WITH NEW CORONAVIRUS INFECTION COVID-19.

The aim of the investigation was to clarify the features of the clinical symptoms of patients with the new coronavirus infection COVID-19.
 Material and methods: A total of 156 patients undergoing treatment in COVID-hospitals were examined. The examination included the determination of the prevalence of: COVID 19 clinical symptoms, COVID 19 clinical manifestations in the oral cavity, concomitant diseases.
 Results. In the structure of general symptoms, complaints of hyperthermia, general weakness and cough (more often dry) played a leading role, which were noted by the overwhelming majority of the examined. Two-thirds of the patients reported body pain. The leading symptoms were also anosmia (in 68.6% of cases) and sweating (64.1%).More than half of the patients complained of shortness of breath (60.2%), difficulty in nasal breathing (55.1%), a feeling of tickling (58.3%) and pain (60.2%) in the throat. Among dental pathology, loss of taste (57.5%) and hyposalivation (38.5%) were the most common in patients. Bleeding gums were detected in 22.4% of the examined patients, which is most likely due to violations of the rheological properties of blood and changes in the hemodynamic provision of the periodontal during Covid19. Clinical manifestations of periodontal pathology do not occur immediately, but in the form of long-term complications. In this regard, it seems necessary to dynamically monitor the condition of patients who have undergone COVID-19 in different time periods.
 Conclusions. Hemostasis disorders characteristic of the new COVID-19 coronavirus infection certainly have an impact on the state of dental status, further destroying periodontal tissues. However, clinical manifestations of pathological effects may not occur immediately, but in the form of long-term complications. In this regard, it is necessary to dynamically monitor the condition of patients who have undergone COVID-19 in different time periods.

Histomorphology of the ovaries of rabbits does during ovulation induced by the combined use of gonadotropins

Hormonal stimulation of folliculogenesis is a general method of increasing reproductive capacity in rabbits; however, studying the safety of the developed protocols remains an urgent scientific task. The use of hormonal agents is due to the physiological characteristics of rabbits, primarily coitus-dependent mechanisms of ovulation. Applying gonadotropin-releasing analogs depends on mature follicles ready for ovulation in the ovary. It, therefore, has limited effectiveness for rabbits of the “zero” cycle that have not yet given birth. Therefore, such females are recommended to use medications based on gonadotropins obtained from the serum of foal mares (eCG) or human chorionic gonadotropin (hCG). There is limited data on the combined use of gonadotropins, especially the long-term administration in different doses. Thus, the research aimed to conduct a morphological evaluation of rabbit's ovaries with combined serum and chorionic gonadotropins to stimulate folliculogenesis before artificial insemination to assess the safety of the proposed dosages and long-term administration. Stimulation of ovulation in rabbits of experimental groups was caused by the combined use of serum and chorionic gonadotropins (eCG – 400 IU; hCG – 200 IU) for experimental groups 1 and 2 at a dose of 40 IU and 24 IU, respectively. Females of the control group were induced to ovulate by subcutaneous injection of 0.2 ml of gonadotropin-releasing hormone analog. Ovaries were collected on the seventh day of gestation after the euthanasia of the rabbit with prior premedication. After dissection and macroscopic examination, the ovaries were fixed in a 10% aqueous solution of neutral formalin. Histological slides were made according to the general method by pouring in paraffin and subsequent staining with hematoxylin and eosin. The research has established that repeated (during five reproductive cycles) combined use of serum and chorionic gonadotropins has dose-dependent effectiveness and can cause dysfunction of ovaries and blood circulation. Pathological changes may acquire a systemic character with the manifestation of critical conditions for the health and life of rabbits. The stimulating effect of the combined use of eCG and hCG was detected at a dose of 40 IU, and the inhibition of folliculogenesis was observed at 24 IU. Since the premises for the hyperandrogenism were found microscopically, it was essential to investigate the level of androgens in the blood of rabbits after using a dose of 24 IU. At the same time, both doses of gonadotropins affect the reactivity of the endothelium, which is manifested by the presence of intravascular vesicles and changes in the rheological properties of blood.

GESTATIONAL PYELONEPHRITIS ACCORDING TO SAMARKAND INDICATORS

In pyelonephritis, the pathogenic factor affecting the chronic stage of inflammation loses its leading role; processes that influence changes in the rheological properties of blood and microcirculation play an important role, which leads to the development of a chronic condition. occurs -the causes of this disease are a risk factor for the mother and fetus, leading to perinatal losses.In patients with acute pyelonephritis, significant changes are observed in the hemostatic system, clinical and laboratory parameters. The above changes intensify during the transition from the serous stage of kidney inflammation to the purulent stage.

Rheological properties of blood in multiple myeloma patients.

Multiple myeloma (MM) is considered to be one of the hematological malignancies formed by excessive and abnormal proliferation of plasmocytes. Among other parameters, several blood tests are used to diagnose multiple myeloma. The hemorheological profile in multiple myeloma is not widely studied. Hemorheology includes the study of measuring the deformability and aggregation of erythrocytes, blood viscosity, and sedimentation rate. The degree of deformability of blood cells is necessary to maintain proper vital functions. Proper deformability of red blood cells ensures proper blood circulation, tissue oxidation and carbon dioxide uptake. The aim of the study was to compare morphology and blood rheology parameters in patients with MM and healthy individuals. The study included 33 patients with MM, and 33 healthy subjects of the same age. The hematological blood parameters were evaluated using ABX MICROS 60 hematology analyzer. The LORCA Analyzer to study erythrocyte aggregation and deformability. Patients with MM had lower red blood cells count (RBC) (9.11%) (p < 0.001) and half time of total aggregation (T1/2) (94.29%) (p < 0.001) values and higher mean corpuscular volume (MCV) (5.50%) (p < 0.001), aggregation index (AI) (68.60%) (p < 0.001), total extent of aggregation (AMP) (87.92%) (p < 0.001) values than the healthy control group. Aggregation in patients with MM is different compared to healthy individuals. It was observed that the percentage of cell aggregation is almost 50% higher than in the control group. The study of morphology, aggregation and deformability of erythrocytes in patients with suspected MM may be helpful in making clinical decisions.

Decreased erythrocyte aggregation in Glenn and Fontan: univentricular circulation as a rheologic disease model.

In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation. We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences. Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation. Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss. Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.

Wobenzyme: correction of coronary disease yhearts and possiblemechanisms of action

The effect of Wobenzym on hemostasis, rheological properties of blood, and the clinical course of the disease when included in the complex therapy of angina pectoris was studied. It has been established that Wobenzym improves the rheologicalproperties of blood by reducing the aggregation ability of erythrocytes and platelets andincreasing the deform- ability of erythrocyte membranes. Wobenzym helps optimize the activity of the fibrinolytic and coagulation systems of the blood, improves the clinical course of angina pectoris and the quality of life of patients. The use of Wobenzym as part of complex therapy for patients with angina pectoris of functional class II is clinically justified, effective and safe.

Computational analysis of patient-specific pulsatile blood flow: The influence of non-Newtonian models on wall shear stress assessment

Blood is a sophisticated biological fluid with components like erythrocytes that give it non-Newtonian behavior. Hemodynamic factors such as velocity magnitude, pressure, and wall shear stress descriptors are the most important factors in the development of atherosclerosis. The wall shear stress descriptors are regulated not only by flow geometry but also by blood rheological properties. In the current study, we carried out a numerical analysis of the non-Newtonian pulsatile blood flow while taking into account a patient-specific geometry and transient boundary conditions. Non-Newtonian blood flow is modeled using the four non-Newtonian models: the power-law model, the Carreau model, the Casson model, and the Quemada model, and compared with the Newtonian model. Streamline analysis vividly illustrates velocity patterns, revealing the presence of recirculation zones near sinus regions. The study suggests the significance of selecting appropriate viscosity models for accurate assessments, particularly in regions with low time-average wall shear stress values, such as those associated with atherosclerotic plaques. The differences in the time-averaged wall shear stress between the four non-Newtonian models were found to be the highest in the Quemada model. The study concluded that the non-Newtonian model is required when the focus is on the low-time-averaged wall shear stress area.

Changes in rheological parameters of blood, microcirculation, and accumulation of antibiotic in the focus of acute inflammation of patients with maxillofacial phlegmon

BACKGROUND: Despite the modern development of dentistry, the frequency of purulent inflammatory diseases of complicated caries tends to increase. Up to 60%–70% of patients had odontogenic phlegmon in maxillofacial hospitals. With the spread of the process to the neck and mediastinum, mortality reaches 60%, and with the generalization of infection leading to septic shock, it increases to 90%. This study aimed to examine the state of rheological parameters and blood microcirculation in cases of acute purulent inflammation in patients with maxillofacial phlegmon based on blood viscosity, analysis of the microcirculatory bed according to laser Doppler flowmetry, and concentration of the antibiotics in the blood. This study will allow us to analyze pathophysiological changes and coordinate adequate drug therapy.&#x0D; AIM: To examine the state and rheological properties of blood in the microcirculation and antibiotic concentration in cases acute purulent inflammation in patients with maxillofacial phlegmon to improve the effectiveness of treatment.&#x0D; MATERIALS AND METHODS: The study enrolled 20 patients. Their age ranged from 28 to 62 years, and there were 13 (65%) men and 7 (35%) women. The average body weight of the patients in the study group was 79–95 kg. All patients under endotracheal anesthesia underwent phlegmon dissection. During the operation and treatment, microcirculation, blood viscosity, and laser Doppler flowmetry were evaluated, and the antibiotic concentration in the inflammation area was assessed.&#x0D; RESULTS: The results of the study of 20 patients were analyzed. As a result of studying the rheological parameters of blood obtained from the peripheral vein in patients with phlegmon of the maxillofacial region of various localization, changes in blood viscosity towards thickening compared with normal values were revealed.&#x0D; CONCLUSION: With acute purulent inflammation of the maxillofacial region, pathophysiological changes occur in the microcirculatory bed, which must be considered when prescribing adequate antibacterial therapy.

Role of Goldenberry (Fruits with Husk) Extract in Ameliorating the Architecture and Osmotic Fragility of Red Blood Cells in Obese Rats.

Goldenberry (GB) is a promising fruit that can be a constituent in many possible nourishments. No notifications were obtained regarding the impact of exposure to goldenberry extract in the viewpoint of blood rheological properties as well as erythrocyte osmotic fragility of red blood cells (RBCs) in obese rats. A substantial reduction in plasma triglyceride, total cholesterol, and LDL, with a considerable increment in HDL levels relative to the obese group (p ≤ 0.05), was observed in rats receiving low and high doses of GB, accompanied by restoration of SOD activity and GSH levels. Rheological parameters of rats' blood have been studied over a wide range of shear rates (225-1875 s-1). A significant decrease in blood viscosity in rats who received low and high doses of GB extract was compatible with every shear rate compared to the control group. The shear stress values of the obese rats reduced appreciably (p ≤ 0.05) in all values of shear rate (from 75 to 500 s-1) proportional to the control group, while in the groups that received low and high doses of GB extract, shear stress was restored to the control values. Finally, administration of GB extract significantly decreased yield stress and indices of whole blood aggregation, with an extremely substantial increment in flow rate, in rats given low or high doses of GB compared to obese ones. The result also showed a decrease in both the average raised osmotic fragility and the hemolysis rate in rats after supplementation with low and high doses of GB extract.

Effect of Heparin on the Formation and Healing of Gastric Ulcers Induced by Acetic Acid Application on the Gastric Mucosa in Rats

The key factor in maintaining the integrity of the gastric mucosa is its normal blood supply, respectively, the use of drugs that improve it, including through a positive effect on the rheological properties of blood, is in demand for the treatment of gastric ulcer. These drugs include the anticoagulant heparin. The aim of the work is to study the effect of heparin on the formation and healing of gastric ulcers induced by the application of 60% acetic acid to the gastric mucosa in rats, while assessing the possible risk of bleeding. After application of acetic acid (day 0), the area of gastric ulcers was assessed on the 4th day (formation of the ulcers) and the 7th day (healing of the ulcers). To assess the effect on ulcer formation, heparin (1000 IU/kg/day, subcutaneously) was administered from days 0 to 3, and on the healing from days 4 to 6 after acid application. To check for possible bleeding under the influence of heparin, the level of hemoglobin in the blood was tested before acid application (basal), on the 4th and 7th days after application. The degree of bleeding was assessed based on the relative decrease in hemoglobin levels. The administration of heparin led to a decrease in the average area of ulcers both on the 4th and on the 7th day compared with that in control rats (heparin vehicle). In control rats, both on the 4th and on the 7th day, the hemoglobin level was reduced compared to the corresponding basal level. Heparin had no effect on the hemoglobin level at day 4, but potentiated the decrease in mean hemoglobin level at day 7, increasing the number of animals having a greater relative decrease in hemoglobin level compared to the corresponding control group. Thus, heparin may have a gastroprotective effect, manifested both in the weakening of the formation of an ulcer and in the acceleration of its healing, however, there is a risk of bleeding when the ulcer heals.

Modelling blood flow in coronary arteries: Newtonian or shear-thinning non-Newtonian rheology?

BackgroundThe combination of medical imaging and computational hemodynamics is a promising technology to diagnose/prognose coronary artery disease (CAD). However, the clinical translation of in silico hemodynamic models is still hampered by assumptions/idealizations that must be introduced in model-based strategies and that necessarily imply uncertainty. This study aims to provide a definite answer to the open question of how to properly model blood rheological properties in computational fluid dynamics (CFD) simulations of coronary hemodynamics. MethodsThe geometry of the right coronary artery (RCA) of 144 hemodynamically stable patients with different stenosis degree were reconstructed from angiography. On them, unsteady-state CFD simulations were carried out. On each reconstructed RCA two different simulation strategies were applied to account for blood rheological properties, implementing (i) a Newtonian (N) and (ii) a shear-thinning non-Newtonian (non-N) rheological model. Their impact was evaluated in terms of wall shear stress (WSS magnitude, multidirectionality, topological skeleton) and helical flow (strength, topology) profiles. Additionally, luminal surface areas (SAs) exposed to shear disturbances were identified and the co-localization of paired N and non-N SAs was quantified in terms of similarity index (SI). ResultsThe comparison between paired N vs. shear-thinning non-N simulations revealed remarkably similar profiles of WSS-based and helicity-based quantities, independent of the adopted blood rheology model and of the degree of stenosis of the vessel. Statistically, for each paired N and non-N hemodynamic quantity emerged negligible bias from Bland-Altman plots, and strong positive linear correlation (r > 0.94 for almost all the WSS-based quantities, r > 0.99 for helicity-based quantities). Moreover, a remarkable co-localization of N vs. non-N luminal SAs exposed to disturbed shear clearly emerged (SI distribution 0.95 [0.93, 0.97]). Helical flow topology resulted to be unaffected by blood rheological properties. ConclusionsThis study, performed on 288 angio-based CFD simulations on 144 RCA models presenting with different degrees of stenosis, suggests that the assumptions on blood rheology have negligible impact both on WSS and helical flow profiles associated with CAD, thus definitively answering to the question “is Newtonian assumption for blood rheology adequate in coronary hemodynamics simulations?”.

Current affairs in the use of medical ozone. Biological effects. Mechanisms of action

Introduction. Oxygen-ozone therapy stands as a medically endorsed practice confirmed by numerous international clinical studies. Various authors have illustrated the beneficial clinical outcomes of ozone therapy in terms of its capacity to regulate redox balance, cellular inflammatory responses, and adaptation to ischemia/reperfusion processes. Ozone therapy extends to encompass a range of viral infections, inflammatory disorders, and degenerative ailments, used as both monotherapy and as an adjunct to unified conventional therapies. Material and methods. Narrative literature review study. Bibliographic search was conducted using the PubMed, Hinari, and SpringerLink databases, as well as the National Center of Biotechnology Information and Medline. Articles published between 1990 and 2022 were selected using various combinations of keywords, including “ozone”, “ozone therapy”, “mechanisms of ozone action”, “biological effects of ozone”, “antioxidant effect”, “anti-inflammatory effect” and “immunomodulatory effect.” Information regarding ozone’s mechanisms of action was identified and processed. Following the database information processing and search criteria, a total of 475 full-text articles were found. The final bibliography consists of 52 relevant sources that were deemed representative of the materials published on the topic of this synthesis article. Results. The effects of ozone on oxygen metabolism are explained by changes in the rheological properties of blood, including inhibition of erythrocyte aggregation and stimulation of 2,3-diphosphoglycerate in erythrocytes, favoring the transport and delivery of oxygen to tissues while facilitating the substantial elimination of nitric oxide and increasing blood flow. Intracellular triatomic oxygen enhances the oxidative carboxylation of pyruvate, stimulating ATP production, which also contributes to reducing peripheral vascular resistance. Conclusions. Ozone generates a moderate oxidative stress. Yet, it can set off several beneficial biochemical mechanisms that reactivate both the intra- and extracellular antioxidant systems and reverse chronic oxidative stress in various inflammatory and degenerative processes. Ozone induces a mild activation of the immune system by triggering neutrophil activation and stimulating the synthesis of certain cytokines (IL-2, TNF-α, IL-6, and IFN-γ), thereby initiating a complete cascade of immune responses. Ozone therapy yields the following biological reactions: optimization of blood circulation and oxygen delivery to ischemic tissue, regulation of cellular antioxidant enzymes, initiation of a slight immune system activation, and enhancing the release of growth factors.

ИЗМЕНЕНИЕ РЕОЛОГИЧЕСКИХ СВОЙСТВ КРОВИ У БОЛЬНЫХ С РИНОСИНУСИТАМИ ПОСЛЕ КОРОНАВИРУСНОЙ ИНФЕКЦИИ

Introduction. The study of the pathogenesis of purulent-inflammatory diseases of the nose and paranasal sinuses is impossible without a comprehensive analysis of various factors of homeostasis and, above all, the state of microcirculation, which largely depends on the rheological properties of blood Under the law common to all forms of fluid movement, as the viscosity of the medium increases, the speed of movement decreases, and the energy costs for its movement increase. Consequently, the deterioration of the rheological properties of blood and microcirculation are directly related. Violation of microcirculation always significantly affects the development of pathological processes. The aim of the study rheological properties of blood in patients with rhinosinusitis after coronavirus infection. Materials and methods. The studying the rheological properties of blood in 55 patients with rhinosinusitis after coronavirus infection are presented. The following main indicators were determined in patients: blood viscosity, erythrocyte aggregation coefficient, degree of deformability of erythrocytes, average volume of one erythrocyte, hematocrit, fibrinogen, morphological properties of erythrocytes. Results and discussion. In all examined patients with rhinosinusitis after coronavirus infection, the rheological properties of blood are sharply impaired. The severity of violations of the rheological properties of blood depended not only on the type of disease, but on its severity and the degree of intoxication of the body. A change in blood viscosity was detected in all examined patients. Blood viscosity indices increased sharply in proportion to the severity and prevalence of the inflammatory process and the severity of destructive changes in the affected organs. Conclusion. The analysis of the conducted studies shows that one of the main manifestations of a violation of the rheological properties of blood in rhinosinusitis after coronavirus infection is intravascular aggregation of erythrocytes, as well as a violation of the ability of erythrocytes to reversible deformation.

Impact of thermal radiation and internal heat generation on Casson nano-fluid flowing by a curved stretchable surface with suspension of carbon nanotubes (CNTs)

The function of present work is to inspect heat transmission of radiative nanofluid in regard to boundary layer description. Carbon nanotubes (CNTs) dependent fluid is being evaluated and it flows overtop a curved stretching surface. Special features, like thermal radiation and internal heat generation, which corresponds to heat transmission along the flow have been incorporated. Dual nature of carbon nanotubes, that is, single walled carbon nanotubes (SWCNTs) as well as multiple walled carbon nanotubes (MWCNTs) together with blood (base fluid) have been utilized for the composition of nanofluid. The rheological properties of blood have been captured using Casson fluid model. Appropriate transformations have been applied to reduce the modeled system of nonlinear partial differential equations into a system of ordinary differential equations (ODEs). To achieve the desired numerical solution of obtained system of ODEs, NDSolve technique is employed using Mathematica. Numerous parameters appearing in governing equations, exert influence on focused physical quantities. Graphs have been engaged to capture these variations for both SWCNTs and MWCNTs. Likewise, numeric charts have been displayed to investigate impressions on skin friction coefficient and Nusselt number for distinct parameters.

Morphoimmunohistochemical changes in the coronary arteries early after stenting

Introduction: Modern methods of surgical treatment for coronary heart disease include stenting and bypass surgery. In this regard, a morphoimmunohistochemical study of the state of the coronary arteries in the early stages after stenting will make it possible to predict postoperative complications. Materials and methods: The protocols of autopsies of 20 deceased were studied (10 men, mean age 64.7 years, 10 women, mean age 76.9 years). In 85 %, progressive stenosing atherosclerosis of the mouth of the left coronary artery (CA) and the anterior interventricular branch was noted. Taking into account the development of complications after stenting, three chronological groups were identified: 1) up to 3 days; 2) 37 days; 3) 715 days. The computer program ImageJ (US National Institutes of Health, USA) was used for CA morphometry. Statistical processing of the obtained results was carried out on a personal computer using the statistical tools of the Statistica 10 program. Result : It was shown that during the first 3 days after stenting of coronary arteries, acute damage to endothelial cells in the form of desquamation, dystrophic and necrobiotic processes, intramural hemorrhages in the areas of atheromas localization are observed in their walls. After 37 days and later, 715 days after stenting of the coronary artery, parietal mixed (fibrin-leukocytic), fibrin thrombi with signs of organization are observed in the lumens of the coronary artery, which is combined with the phenomena of neoangiogenesis of the artery wall. Conclusions: Damage to endothelial cells and related disturbances in the rheological properties of blood due to the expression of von Willebrand factor can initiate endothelial dysfunction with the development of thrombosis, thromboembolism of small coronary branches, which can cause myocardial perfusion disorders with the development of acute infarction.