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The growing number of studies on cerebral venous circulation disorders associated with extrinsic stenosis of the internal jugular veins, as well as attempts to surgically influence the restoration of blood flow, are an indicator of the importance of this problem. Studies show that extracranial outflow disorders are associated with a wide range of neurological clinical manifestations and may contribute to the development of congestive intracranial hypertension. Anatomical variants of the development of the extracranial venous system, constitutional insufficiency and stenosis often play similar roles in the development of disorders of the cerebral venous outflow, but differ parametrically. There are no standard diagnostic criteria for differential diagnosis, normal and pathological parameters are contradictory, and the diagnosis largely depends on the combined use of imaging techniques. The history of attempts to study disorders of the cerebral venous circulation is quite long, associated with the technical innovations in every period of time. The most non-invasive, accessible and safe tools for diagnosing non-thrombotic lesions and anomalies of the internal jugular veins are currently recognized as ultrasound scanning and MR venography in tandem. Researchers note both local hemodynamic disturbances at the level of stenosis and changes in the overall picture of the venous vascular network of the neck with certain patterns of its remodeling. The pathological significance of the compensatory expansion of nonjugular outflow tracts (vertebral, paraspinal collateral, spinal epidural veins, etc.) is still a controversial issue. MRI and ultrasound combined show a high degree of agreement between the results, which should stimulate further research into the pathophysiology and differentiation of various causes and severity of non-thrombotic lesions of the jugular veins.

Purpose: to determine objective echographic criteria for the differential diagnosis of anterior ischemic optic neuropathy (AION) and optic neuritis (ON).Material and methods. The research involved 60 patients aged 40 to 60 years, including 30 patients with suspected AION and 30 patients with suspected ON. The control group consisted of 40 healthy volunteers. In addition to the standard ophthalmological examination, all patients underwent ultrasound optic nerve s examination with measurement of the optic nerve thickness and acoustic density (AD) of the parenchyma and optic nerve sheets. Assessment of blood flow in retrobulbar vessels was carried out in the modes of Color Doppler Imaging and pulse dopplerography.Results. There were no statistically significant differences in average echographic parameters of the optic nerve s thickness between the groups of patients with AION and ON. In patients with ON there was a statistically significant decrease in the average AD index compared to that in patients with AION and in healthy volunteers (106.02 ± 5.40 y. e., 146.58 ± 9.70 y.e. and 135.3 ± 2.1 y. e., accordingly). The AD values in all patients with AION exceeded 133 y. e., in patients with ON this index was less than 132 y. e. Evaluation of hemodynamic parameters in the vessels of the eye demonstrated a statistically significant decrease in the peak systolic velocity (Vsyst) and end-diastolic velocity (Vdiast) blood flow in the central retinal artery and medial and lateral short posterior ciliary arteries in patients with AION (in 2-fold) compared with ON and normal indices (p < 0.001). There were no statistically significant differences between parameters of blood flow in patients with ON and in healthy volunteers. In addition, there were no significant intergroup differences of hemodynamic parameters of the ophthalmic artery (p > 0.05).Conclusions. AD of the optic nerve and parameters of blood flow velocities (Vsyst and Vdiast) in medial and lateral short posterior ciliary arteries can be attributed to the diagnostic criteria of the AION and ON.

The review presents information about the basic knowledge about the regulation of blood flow in the retina, based on data obtained in animal experiments using invasive methods. Along with the well-known instrumental methods for diagnosing vascular pathology of the eye, new high-tech methods for studying the microcirculation of the eye are used, which make it possible to most reliably assess the degree of circulatory disorders in the vessels of the eyeball. Thanks to the development of non-invasive ultrasound research methods, it became possible to study in more detail the state of blood flow in the vessels of the eyeball in people with vascular pathology of the eye. An important feature of the eye hemodynamics is its dependence on intraocular pressure and the presence of self-regulation of blood flow in the retina, including changes in the illumination of the retina, blood pressure, and so on. The blood supply to the eye can also be affected by pharmacological agents that are commonly used in the treatment of systemic diseases.

The paper describes the effect of para-pharmaceutical features of Virilis containing Cordyceps sinensis, Fructus Liccii, Coix Lachrima jobi and Royal jelli on blood supply to the male reproductive system (MRS) in patients with erectile dysfunction (ED) and chronic prostatitis. The technique is Doppler ultrasound blood vessels of the penis, prostate, testicular after a single and five weeks reception of Virilis. A significant increase in blood flow of velocity of integral indicators MEAs is viewed. Research justifies the use of Virilis in patients with erectile dysfunction and hemodynamic prostatopathy.

A finite element modelling of the process of the heat transfer from blood to the wall of an arterial vessel was carried out in order to solve a more general problem of determining the relationship between the amplitude-frequency characteristics of fluctuations in the volumetric blood flow velocity in peripheral vessels with temperature oscillations on the skin surface. A model was built in the ANSYS software with Fluid Flow CFX module which includes domains related to blood, the wall of a cylindrical vessel, and skin (bio-tissue). The model takes into account the convective heat transfer from blood to the vessel wall and thermal conductivity in the skin. The corresponding boundary value problem is posed which includes the Navier – Stokes equation and the Fourier heat equation. Dependences of the temperature oscillations of the vessel wall on the amplitude of fluctuations in the volumetric blood flow velocity in a wide frequency range of 0.01–1 Hz were obtained. The selected frequency range covers all currently known rhythms of hemodynamic fluctuations: endothelial, neurogenic, myogenic, respiratory and cardiac. A function is proposed that approximates the dependence of the amplitude of vessel wall temperature oscillations on the amplitude of the oscillations of the volumetric blood flow at various values of the blood flow velocity modulation frequency. The use of the introduced approximating function together with the solution of the heat equation for a thermal wave opens up the possibility of solving the inverse problem of determining the dynamics of volumetric blood flow in an arterial vessel based on the data on the temperature dynamics on the skin surface.

Introduction. Cerebral small vessel disease (CSVD), associated with age and vascular risk factors, as well as the main cause of vascular and degenerative mixed cognitive impairment (CI). Previously established microstructural predictors of CI (axial diffusion in normal-appearing periventricular white matter of the posterior left frontal lobe, the right midcingulate cortex, and the middle posterior part of the corpus callosum) can be used to calculate an integrative factor, exceeding the threshold value for which indicates the presence of CI. The use of this factor in the diagnosis of CI in CSVD is supported by the fact that leading mechanisms of CSVD are involved in the damage to areas of the brain that are strategic for CI. The aim of this study was to clarify the link between the known microstructural predictors of CI in CSVD and MRI findings that correspond to the main mechanisms of CSVD. Materials and methods. Patients (n = 74; including 48 women; average age 60.6 6.9 years) with CSVD and CI of varying severity underwent phase-contrast MRI and voxel-based morphometry (3T) to assess arterial, venous and CSF flow, as well as atrophy. Results. The established microstructural predictors of CI correlated with measures of arterial and venous blood flow, as well as atrophy. Linear regression models allow us to estimate cognitive impairment (CI) predictors in cerebral small vessel disease (CSVD), based on increased arterial velocity pulse index, CSF flow at the level of the cerebral aqueduct, cerebral aqueduct area and lateral ventricles volume, when there is reduced blood flow in the superior sagittal sinus and the overall arterial blood flow. Conclusion. The ability to calculate microstructural predictors of CI due to CSVD, based on MRI findings, indicates the validity of using an integrative measure of microstructural predictors of CI as a diagnostic tool of CI in CSVD.

This study aims to determine the existing pathways of collateral cerebral circulation in parasagittal meningiomas that cause superior sagittal sinus occlusion based on literature review and analysis of own clinical observations. Results of clinical and instrumental examination of 221 patients treated in Dnipropetrovsk Regional Clinical Hospital named after I.I. Mechnikov from 2000 to 2021 were subjected to retrospective and prospective analysis. Inclusion criteria were:patient age of 18+, parasagittal extracerebral tumor according to computed tomography/magnetic resonance imaging, histologically verified meningioma, superior sagittal sinus occlusion (type V-VI according to M.P. Sindou and J.E. Alvernia) according to selective cerebral angiography. This study is based on the analysis of examination of 43 patients who met the inclusion criteria. The selected patients were analyzed for demography (sex, age), brain computed tomography/magnetic resonance imaging before and after intravenous contrast enhancement, and computed tomography angiography and selective cerebral angiography data. Transformed venous drainage pathways were analyzed depending on the location of superior sagittal sinus occlusion by parasagittal meningioma: anterior, middle, or posterior third of the superior sagittal sinus. It was determined that preoperative diagnosis of parasagittal meningiomas that, based on brain computed tomography/magnetic resonance imaging, has signs of type V or VI superior sagittal sinus invasion according M.P. Sindou and J.E. Alvernia, must include selective cerebral angiography. Dynamic images of selective cerebral angiography in the venous phase allows to fully assess the established pathways of collateral blood flow and the blood flow direction. Information on collateral venous circulation in case of superior sagittal sinus occlusion by parasagittal meningioma is extremely important in a surgery planning. It helps avoiding iatrogenic damage to eloquent veins, which increases radical tumor removal with maintaining/improving a patient’s functional state in the early postoperative period and improving long-term treatment outcomes. [ABSTRACT FROM AUTHOR]

The aim. To assess the hemodynamic parameters of the hepatic and visceral blood flow in patients with compensated and decompensated liver cirrhosis. Materials and methods. 290 patients with liver cirrhosis were examined: 206 had gastrointestinal bleeding, 84 had diuretic-resistant ascites. Ultrasonic scanning, Doppler sonography, esophagogastroduodenoscopy, angiography, radioisotope scintigraphy were performed to assess blood flow in the portal, splenic and superior mesenteric veins and in the hepatic, splenic and superior mesenteric arteries. Results. Change in the hepatic microcirculatory blood flow in the natural course of liver cirrhosis was characterized by decreased portal and increased arterial blood flow, “arterialization” of hepatic blood flow based on scintigraphy. Decompensation of the disease was associated with progressive reduction in both portal and arterial hepatic blood flow, which were correlated with the severity of functional liver disorders regardless of the complication nature. The portal blood flow in the natural course of liver cirrhosis was characterized by 3.5–4.5 times increased volume of visceral blood. Decompensation of the disease was accompanied by a decrease in blood flow in the portal vein as compared to the splenic and superior mesenteric veins by 1.8–2.2 and 1.5–2.7 times, respectively. Arterial blood flow in the natural course of liver cirrhosis was characterized by a relatively increased hepatic arterial flow. The ultrasound criterion of hepatic blood flow “arterialization” was an increase in hepatic-splenic arterial index, which can be used as a sign to differentiate between different forms of portal hypertension. Decompensation of the disease was characterized by an average of 8.2 % decreased arterial blood flow in the hepatic artery compared to the splenic artery in dynamics. Prognostically unfavorable signs were the progression of splenomegaly degree, the increase in the portal vein diameter with the decreased velocity characterizing the increase in congestive index by 2.4–2.6 times, the decrease in the hepatic artery diameter and velocity in it over time.Conclusions. The hepatic and visceral blood flow characteristics should be considered when choosing method of conservative, surgical or minimally invasive treatment of liver cirrhosis complications. Based on the hepatic hemodynamic characteristics, the mismatch between portal perfusion (reduced) and visceral blood flow (increased) is the essence of portal hypertension in liver cirrhosis. Accordingly, the criterion of treatment effectiveness in decompensated liver cirrhosis should be improved portal liver perfusion and (or) reduced volume of visceral blood flow.

Purpose To explore the value of ultrasound in the treatment of bone union at the docking site by accordion technique. Methods Sixteen patients were recruited. The accordion operation was performed at the docking site after bone transport. The specific operation process was compression, suspension of adjustment, distraction, retraction. Ultrasound was used to monitor the hematoma, blood flow and callus in and around the docking site at each stage. Results (1) At the compression, there were 14 cases with hematoma and 2 cases without hematoma. (2) The size of hematoma was negatively correlated with the bone healing time of the docking site and the blood flow resistance index. (3) The Adler grading of blood flow gradually increased before the retraction, and then gradually decreased. But the degree of callus mineralization continued to rise. Conclusion (1) Ultrasound can dynamically monitor the change trend of hematoma, blood flow and new callus at the docking site during accordion operation, so as to predict the tendency of bone healing at the docking site. (2) This study can preliminarily demonstrate that the compression stress applied in accordion technique can promote the bone healing at the docking site.

The most important factors in the development of chronic haemorrhoids today are considered to be the combination of two factors (vascular and mechanical) that lead to the development of hemorrhoids. The underlying vascular factor is the vascular dysfunction, providing arterial blood flow through the arteries to the cavernous bodies and outflow through the cavernous veins, which leads to dilation of cavernous bodies and the formation of vascular malformations.There were performed clinical examination and treatment of 140 patients with chronic hemorrhoids of stage III-IV according to Goligher. The features of arterial blood supply of the anal canal were evaluated by transrectal ultrasound examination.It was found that there was no clear linear relationship between the number of anal arteries with increased blood flow and the number of hemorrhoidal nodes in the patient. Each node was supplied with blood from one or two arteries: the node placed at 11 o'clock had blood supply from the arteries visualized at 10 and 11 o'clock, the node at 3 o'clock - arteries at 3 and 5 o'clock, the node at 7 o'clock - arteries at 7 and 9 o'clock. The arteries were most frequently visualized at the first (89.4%), the third (93.3%), the seventh (88.8%) and the eleventh (93.4%) hours. With less frequency the hemodynamically significant arteries were visualized at the fifth (65.0%), the ninth (62.8%) and the tenth (66.7%) hours. The arteries that were suppliing blood hemorrhoidal vessels were located in the internal sphincter at a depth of 5 to 10 mm. In the area of 3, 7 and 11 hours, they overlapped with a mosaic pattern that corresponded to the localization of the cavernous body and resembled an arteriovenous fistula according to the СDS.

Relevance. The ocular surface is composed of various tissue components, and all of these components work together to maintain the integrity and normal function of the ocular surface.Aim of the work: to study of indicators of the blood flow of the bulbar conjunctiva and the state of the corneal epithelium in a group of conventionally healthy individuals and assessment of their physiological relationship.Materials and methods. The study involved 20 apparently healthy people (40 eyes) of the Caucasian race, aged from 25 to 53, without concomitant ophthalmopathology. During the examinations, the state of the cornea (thickness of the cornea, epithelium) and bulbar conjunctiva were determined. The study of patients was carried out for 5 months from May to October 2020 on the basis of the Department of Eye Diseases of the State Institution "Zaporozhye Medical Academy of Postgraduate Education of the Ministry of Health ofUkraine" in the Department of Eye Microsurgery inZaporizhzhiaRegionalClinicalHospital.Results. With the help of angio-optical coherence tomography, the density of vessels of the superficial and deep plexuses of the conjunctiva were studied and the normative base of conventionally healthy patients was formed. The density of the vessels of the superficial plexus at a distance of 1, 2 and 3 mm from the limbus did not differ significantly and averaged 50.7 µm. The density of the vessels of the deep plexus on average was 55.7 µm, but did not differ significantly from the indices of the superficial plexus. In the study of the density of the vascular bed of the deep plexus, statistically significant (pConclusions. The proposed normative reference values of a group of healthy individuals will allow both to adequately assess the functional ability of the corneal epithelium, to assess the density of blood flow of the bulbar conjunctiva and episclera, and to timely rationally select personally pathogenetically justified treatment and rehabilitation measures, taking into account the severity of pathological changes in the cornea at the subclinical stage.

The article analyzes the state of patients visual acuity after successful surgical treatment of retinal detachment. On the basis of gathered data, it was concluded that in case of detachment of the macula only in 50% of cases it is possible to increase visual acuity to 0.4 and higher. Restoration of visual functions continues for at least 6 months after the operation and is determined by the restoration of the structure of the outer segments of the photoreceptor cells. During this time, it is advisable to conduct drug therapy aimed at normalizing blood flow and functional activity of the retina. Visual functions recovery continues for at least 6 months after the operation and is connected with the restored structure of the outer segments of the photoreceptor cells. Important prognostic factors of central vision restoration in the postoperative period are visual acuity before surgery, duration of existence and height of macular detachment. Data on which of the methods of surgical treatment of retinal detachment allows to achieve higher visual acuity are contradictory. There is practically no data on the comparison of the effect on visual acuity of scleral buckling and vitrectomy in the long-term period, in patients with phakic eyes and with artiphakia. On visual acuity after fitting detachment of the macula may affect macular edema, epiretinal membrane formation and retinal folds, and edema of the peripapillary optic nerve head, progressive deterioration of blood flow in the basin of the central retinal artery, short posterior ciliary arteries and ophthalmic artery. It is believed that these factors are significantly more pronounced after scleral buckling than after vitrectomy. Some indicators of optical coherence tomography correlate with visual acuity after surgical treatment of retinal detachment: the state of the articulation line of the external and internal segments of the photoreceptors, as well as the state of the external limiting membrane.

Copyright of Otorhinolaryngology (25288253) is the property of Ukrainian Oto-Rhino-Laryngological Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: classical methods of determining arterial blood supply of the graft following orthotopic liver transplantation (OLT) reflect the presence of blood flow in the trunk and large branches of the A. hepatica, without the characteristic of completeness of blood filling of peripheral sections, which is very important for objective evaluation of function. The aim of this study is to establish the diagnostic value of a direct perfusion study (IFlow) of the graft. Materials and methods. From 1998 to 2019, 245 OLTs were conducted. From 2015 to 2019, arterial changes were detected in 24 (23%) patients after 104 OLTs. A perfusion study was performed in 9 patients with suspected arterial graft failure. According to the IFlow study, liver hypoperfusion due to stenosis and/or splenic steal syndrome was detected in 8 cases and became an indication for therapeutic intervention. Results. Hepatic stenting and/or splenic artery embolization was performed to improve arterial blood supply to the liver. Endovascular procedures performed restored the perfusion index from 0.24 (0.01–0.89) to 0.61 (0.35–0.98). Conclusion. Absence of ultrasound and multispiral computed tomography signs of arterial complications does not rule out the need for perfusion angiography. Perfusion angiography allows to objectify the angiography data and perform corrective intervention in good time.

Background and Objectives: Interest in the study of the human’s sweat glands activity is due to the close relationship of their activity with human body’s peripheral regions sympathetic innervation. The increased activity of sweat glands and secretion occurs not only due to thermoregulation, but also is a response to the psychoemotional load and the physiological and drug tests. Sweat gland activity’s disruption manifests itself in pathologies such as diabetes mellitus, chronic heart failure, hyperhidrosis, thyrotoxicosis, and Parkinson’s disease. Thus, the search for a method for quantifying the sweat glands activity on the surface of a human body based on physical methods is relevant for biomedical diagnosis. Materials and Methods: The primary thermographic data were recorded using a ThermaCam SC 3000 thermal imaging camera, FLIR Systems (Sweden) with a 34/100 macro lens, in the spectral range of 8–9 μm with a temperature sensitivity of 0.02°C and a resolution of 320  240 pixels with a frequency 5 frames per second. The measurements were performed in laboratory conditions with a stable ambient temperature of 23 ± 0.2°C and the absence of forced convection. Simultaneously with temperature measurements, the volumetric blood flow was monitored using a KL-72001 photoplethysmographic sensor (Taiwan) at a wavelength of 800 nm. Results: The both hands reaction to a breathing test was observed. The dynamics of changes in the active sweat pore count, temperature and blood flow was analyzed. Using an algorithm for processing thermograms that implements the suppression of low-frequency and high-frequency spatial components of temperature fluctuations, and the subsequent detection of local minima, makes it possible using the infrared thermography method to study not only the temperature dynamics, but also the sweat glands activity. Conclusion: Thus, the thermographic recording of the limb’s reaction to a respiratory test using the algorithm for detecting the sweat pore count can be positioned as a tool for studying the body’s sympathetic response to a functional load. The method is interest for the prophylactic detection of small vessel’s neuropathy’s various forms in diabetes mellitus, thyroid disorders and Raynaud’s syndrome.

We studied the changes in central hemodynamics in the early recovery period after physical load in 28 young men. Dynamic loading was induced using a modified Martine functional test, static loading - by maintaining on the standing dynamometer DS-200 muscle effort in the amount of 50% of maximum standing force. The change in central hemodynamic parameters was recorded by tetrapolar thoracic impedance rheoplethysmogram using a computerized diagnostic complex «Cardio +». Dynamic exercise during early recovery did not lead to a significant increase in heart rate, however, it caused a decrease in the resistance of resistive blood vessels and an increase in pulse blood pressure. The increase in minute blood volume in our study is mainly due to an increase in stroke volume, pointing for high functional reserves of the heart. In the case of static physical activity, the adaptive reactions of central hemodynamics and the course of the processes of early recovery of the circulatory system are radically different from similar indicators during dynamic physical activity. In subjects with a normodynamic type of response of the cardiovascular system to dynamic load, no significant changes in the minute volume of blood flow were registered at a similar volume of active muscle mass static load. In subjects with a normodynamic type of cardiovascular response to dynamic load, no significant changes in cardiac output were observed at a similar static load in terms of active muscle mass. However, during early recovery period, the total peripheral vascular resistance and systolic arterial pressure were increased. The increase in total peripheral resistance may be due to reactive hyperemia in ischemic skeletal muscle caused by increased blood flow to the capillaries after muscle relaxation and delayed outflow into the veins. The significant increase in systolic blood pressure can be explained by the mechanical obstruction of blood flow in the muscle capillaries during prolonged static contraction. [ABSTRACT FROM AUTHOR]

The article provides the reader with a number of strategies to the research of blood vessels and tissues of human eye by contactless optical methods. Techniques and apparatus for measuring of geometric parameters of the blood vessels, blood flow velocity and concentrations of ocular tissues chromophores are described. The research is aimed to reveal the most effective diagnostic criteria of vascular abnormalities by means of affordable to measure indicators.

The blood flow in the skin of the temporal region and the functional state of the muscles were investigated using the speckle-optical method. It is shown that the speckle-optical method can be used to objectify the skin blood flow and to evaluate vascular reactivity during breath-holding and hyperventilation. Obtained objective data of the tonic state of the anterior tibial muscle of healthy people can be used as indicators of the norm in the clinic for comparison with the results of examinations of patients with diseases of the motor sphere and the pathology of the neuromuscular apparatus, as well as in sports medicine.

Methodical and software has designed to implement the method of speckle visualization. The treatment options has experimentally grounded. They are the most optimal from the point of view of compliance with the space-time resolution and computation time.

Results of large eddy simulation of three-dimensional flow in a model of the blood vessel with a one-side 70% stenosis at a Reynolds number of 1800 are presented. The Germano-Lilly model was used for subgrid viscosity evaluation. It has been established that the time-averaged flow behind the stenosis is characterized by the presence of two zones of recirculation flow: (i) an extensive zone that arises just behind the stenosis and has a length of about five vessel diameters, and (ii) a relatively small zone positioned near the opposite wall at a distance of about four calibers from the stenosis center. When a high-velocity jet is formed within the stenosis region, a secondary flow also forms as a pair of counter-rotating vortices, which are similar to the Dean vortices in a curved tube flow. The vortex pair arisen in the stenosis leads to a bifurcation of the high-velocity jet and induces also a cross-flow in the reverse flow zone behind the stenosis. The cross-flow almost completely disappears at a distance of less than ten calibers from the stenosis. Hydrodynamic instabilities that are peculiar to the high-gradient mixing layer, which is formed at the boundary of the jet and the reverse flow zone, initiate turbulence occurring with formation of three-dimensional vortex structures of different scales. These structures fill the entire cross-section of the vessel near the flow reattachment point. Turbulent shear stresses are significant in magnitude only at a flow section of about four-caliber length in the vicinity of the reattachment point. Further downstream, the flow relaminarises.

The study of the physiological and pathophysiological processes in the cardiovascular system is one of the important contemporary issues, which is addressed in many works. In this work, several approaches to the mathematical modelling of the blood flow are considered. They are based on the spatial order reduction and/or use a steady-state approach. Attention is paid to the discussion of the assumptions and suggestions, which are limiting the scope of such models. Some typical mathematical formulations are considered together with the brief review of their numerical implementation. In the first part, we discuss the models, which are based on the full spatial order reduction and/or use a steady-state approach. One of the most popular approaches exploits the analogy between the flow of the viscous fluid in the elastic tubes and the current in the electrical circuit. Such models can be used as an individual tool. They also used for the formulation of the boundary conditions in the models using one dimensional (1D) and three dimensional (3D) spatial coordinates. The use of the dynamical compartment models allows describing haemodynamics over an extended period (by order of tens of cardiac cycles and more). Then, the steady-state models are considered. They may use either total spatial reduction or two dimensional (2D) spatial coordinates. This approach is used for simulation the blood flow in the region of microcirculation. In the second part, we discuss the models, which are based on the spatial order reduction to the 1D coordinate. The models of this type require relatively small computational power relative to the 3D models. Within the scope of this approach, it is also possible to include all large vessels of the organism. The 1D models allow simulation of the haemodynamic parameters in every vessel, which is included in the model network. The structure and the parameters of such a network can be set according to the literature data. It also exists methods of medical data segmentation. The 1D models may be derived from the 3D Navier - Stokes equations either by asymptotic analysis or by integrating them over a volume. The major assumptions are symmetric flow and constant shape of the velocity profile over a cross-section. These assumptions are somewhat restrictive and arguable. Some of the current works paying attention to the 1D models validation, to the comparing different 1D models and the comparing 1D models with clinical data. The obtained results reveal acceptable accuracy. It allows concluding, that the 1D approach can be used in medical applications. 1D models allow describing several dynamical processes, such as pulse wave propagation, Korotkovs tones. Some physiological conditions may be included in the 1D models: gravity force, muscles contraction force, regulation and autoregulation.

The literature review contains information on the anatomical and physiological features of the vessels of the conjunctiva, iris, ciliary body. There are data on the development and application of new non-invasive methods for the study of hemodynamics in the microvessels of anterior eye segment. To study the blood flow of the anterior segment of the eye, biomycroscopy, photography and videobiomicroscopy, television biomicroscopy of vessels, darkfield visualization, application fluorescence angiography, photoacoustic angiography, orthogonal polarization spectroscopy, laser Doppler flowmetry and OCT-angiography were used in recent years. These methods allow to determine the qualitative and quantitative characteristics of conjunctiva, iris, ciliary body microcirculation. They are highly informative for assess of various drugs effect on the vascular eye system. Investigation of hemodynamics in the eye microvessels is necessary for a fundamental approach to the study of the pathophysiology of systemic circulatory pathologies (with arterial hypertension, diabetes, etc.) and changes in regional blood flow in organ of vision disease. Monitoring of anterior segment microcirculation in clinical practice makes possible to monitor the effectiveness of drug and surgical treatment.

The aim of the study was to perform a series of in vitro tests of a prototype of the developing heart valve prosthesis to evaluate its functional characteristics. Materials and methods. In this work we have used the frames and full prototypes of the prosthesis, consisting of a stent-like stainless steel support frame with mounted biological leaflets and cover. The authors evaluated the calculated and experimental forces necessary for the displacement of the sutureless implanted prosthesis using the test machine under uniaxial tension. The risk of defects and damages to the supporting framework as a result of implantation was evaluated by scanning electron microscopy. The hydrodynamic characteristics of the prosthesis were investigated under physiological conditions and «valvein-valve» implantation. Evaluation of the ergonomics and applicability of the proposed construction on the cadaver heart model of cattle was carried out. Results. As a result of the forces assessment, it was found that the force required to shear the prosthesis was 3.12 ± 0.37 N, while the calculated value was 1.7 N, which is significantly lower than the obtained value. The comparison of the images obtained with small and large magnifications demonstrated the absence of critical surface defects. Additional analysis under the super-large magnifications also did not reveal problem areas. During the hydrodynamic study, it was shown that the average transplant gradient increased slightly from 2.8–3.4 to 3.2–4.5 mm Hg for the initial prosthesis and the «valve-in-valve» complex, respectively. The decrease of the effective orifice area was 6–9% relative to the initial one. Evaluation of the implantation technique demonstrated the consistency of the approach: the use of the developed holder in combination with the balloon implantation system made it possible to position the prosthesis throughout the procedure. Conclusion. The series of tests demonstrates the consistency of the developed design, intended for the replacement of a failed prosthetic valve of the heart with the «valve-in-valve» implantation.

The purpose of research was to develop a mathematical model for pulsating blood flow in the part of aorta with their branches. Since the deformation of this most solid part of the aorta is small during the passage of the pulse wave, the blood vessels were considered as non-deformable curved cylinders. The article describes the internal structure of blood and some internal structural effects. This analysis shows that the blood, which is essentially a suspension, can only be regarded as a non-Newtonian fluid. In addition, the blood can be considered as a liquid only in the blood vessels, diameter of which is much higher than the characteristic size of blood cells and their aggregate formations. As a non-Newtonian fluid the viscous liquid with the power law of the relationship of stress with shift velocity was chosen. This law can describe the behaviour not only of liquids but also dispersions. When setting the boundary conditions at the entrance into aorta, reflecting the pulsating nature of the flow of blood, it was decided not to restrict the assignment of the total blood flow, which makes no assumptions about the spatial velocity distribution in a cross section. In this regard, it was proposed to model the surface envelope of this spatial distribution by a part of a paraboloid of rotation with a fixed base radius and height, which varies in time from zero to maximum speed value. The special attention was paid to the interaction of blood with the walls of the vessels. Having regard to the nature of this interaction, the so-called semi-slip condition was formulated as the boundary condition. At the outer ends of the aorta and its branches the amounts of pressure were given. To perform calculations the tetrahedral computer network for geometric model of the aorta with branches has been built. The total number of meshes is 9810. The calculations were performed with use of the software package ABACUS, which has also powerful tools for creating geometry of the model and visualization of calculations. The result is a distribution of velocities and pressure at each time step. In areas of branching vessels was discovered temporary presence of eddies and reverse currents. They were born via 0.47 s from the beginning of the pulse cycle and disappeared after 0.14 s.

The regulatory mechanisms of oxygen regime in muscle cell by O2 free diffusion from the microcirculatory to tissue and intracellular diffusion O2 transport to the mitochondria were considered. Diffusion O2 pathway to tissue is divided on 2 parts the first - convective intravessel O2 flow and its leak from microvessels to tissue, the second - intracellular diffusion O2 to mitochondria. The analysis of mathematical modeling and literature data showed: in skeletal muscle there is a functional nutritional network, which changes its structure and properties depending on blood flow velocity and the density of microcirculation in skeletal muscle (1), the self-regulation of the diffusion O2 transport from blood to tissue counteracts hyperoxia at rest and hypoxia under workload (2). Tissue oxygen regime under circulatory, gemic and hypoxic hypoxia was studied. Mean value of cell O2 uptake (VO2) shown to be preserved at hypoxia if mitochondrial oxidative power is distributed according to VO2 gradients. Uneven intracellular distribution of mitochondria reduces the diffusion barriers inside the cell and regulates cellular oxygen regime by weakening tissue hypoxia and counteracting the suppression of tissue respiration, [ABSTRACT FROM AUTHOR]

The authors presented results of blood flow examination in soft and bone tissues masses of lower extremities. Qualitative and quantitative blood flow indices were studied compared and systematized using color-coded Doppler technique and spectral dopplerography.

Introduction. The knee osteoarthrosis leads to a significant reduction of working ability. as well as to disability of working-age people. Arthroplasty is dominated the main method in treatment of such patients. However, many orthopedists are more and more inclined to the surgeries which allow to preserve the knee anatomic-and-functional integrity and to delay the surgery of the knee total replacement for later periods. Subchondral tunnelization with infusing autologous blood with bone marrow elements is one of such methods. of treatment for the patients of this category.Purpose to study the dynamics of the blood flow in the tibial epiphyseal subchondral zone after tunnelization and infusing autologous blood with bone marrow elements and its effect on the rehabilitation process of patients with gonarthrosis.Material and methods. The work was based on the results of studying 26 patients with Degree grade 2-3 gonarthrosis. Surgical treatment included performing tunnelization of femoral and tibial condyles with infusing autologous blood containing bone marrow elements. Circulation of tibial subchondral epiphyseal zone was studied in the operation room, before surgery, after tunnelization and after infusing autologous blood. Blood flow registered using high-frequency ultrasonic Dopplerography. The patient functional condition and the pathology severity analyzed using complex index score.Results. The significant (42-108%, р

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Hemostatic system serves the organism for urgent repairs of damaged blood vessel walls. Its main components - platelets, the smallest blood cells, - are constantly contained in blood and quickly adhere to the site of injury. Platelet migration across blood flow and their hit with the wall are governed by blood flow conditions and, in particular, by the physical presence of other blood cells - erythrocytes. In this review we consider the main regularities of this influence, available mathematical models of platelet migration across blood flow and adhesion based on "convection-diffusion" PDEs, and discuss recent advances in this field. Understanding of the mechanisms of these processes is necessary for building of adequate mathematical models of hemostatic system functioning in blood flow in normal and pathological conditions.

To assess the functional characteristics of erythrocytes in healthy young 109 people 22-35 years are not physically practicing regularly.The lack of physical activity among young people 22-35 years old leads to negative changes in lipid composition of red blood cells, increase in their lipid peroxidation, contributing to decrease the content in the bloodstream of their discoid shapes. This is accompanied by thickening of blood over the potential dilution, gradually growing to 35 years old.

With the help of innovative research methods (such as probing and scanning electronic microscopy, transmission microscopy) the examination of placenta, umbilical cord, endometrium, myometrium and maternal blood for the presence of severe preeclampsia was held. It was shown that poor circulation in the structural components of the studied tissues and organs, as well as changes in cytoarchitectonics and functional properties of red blood cells may be a component of ICE launch - a syndrome with subsequent breach of maternal and fetal life. Application of dipyridamole (Curantil®) improves maternal-placental blood flow, increasing the risk of weakening the blood coagulation and helping to improve blood flow to the capillaries of the placenta and myometrium.