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This research deals with the study of blood microcirculation peculiarities. Materials and methods. 72 students of Bogdan Khmelnytsky Melitopol State Pedagogical University, aged 18–19, were examined. The experimental research consisted of the study of blood microcirculation functional state by means of Laser Doppler flowmetry (LDF) method. It helped to evaluate the state of tissue blood-circulation and to detect individual-typological peculiarities of blood microcirculation under the influence of physical activity (before and after exercise). Results.Three types of blood microcirculation were identified by using LDF-metry. The normoemic type of blood microcirculation, characterized by the superposition of oscillatory rhythms and reflected the balance of the mechanisms of regulation of microcirculation. The hyperemic type, characterized by a «monotonous» LDF-gram with a high parameter of microcirculation, which reflects the relative predominance of metabolic mechanisms in the regulation of microcirculation. The hypoemic type, characterized by a «monotonous» LDF-gram with a low parameter of the microcirculation parameter, which reflects the decrease of vasomotor mechanisms in the regulation of microcirculation. According to the LDF-metric data, the examined students under intensive physical activity have a significant increase in microcirculatory status: by 6 % of the microcirculation parameter, by 28 % of the mean square deviation and by 45 % of the initial value of the coefficient of variation. Conclusions.This dynamics of microcirculation shows that under the influence of physical exertion, a person creates significant functional reserves for the redistribution of blood flow and for more perfect intraorgan capillary blood flow. It was found, that in the process of physical activity, morpho-functional rearrangements of the human cardiovascular system occur. This reaction is formed by several components of blood microcirculation: blood flow in the transport direction, regulating blood supply in accordance with the needs of tissues and the exchange component of the histochemical barrier

In modern clinical practice, the assessment of the state of blood microcirculation and the diagnosis of microcirculatory disorders are extremely relevant in a variety of diseases: in cardiology, diabetology, oncology, dermatology, dentistry, surgery and resuscitation. Microcirculatory disorders are very diverse both in their pathogenesis and in clinical manifestations. Therefore, in the pattern of various diseases and extreme conditions, as well as in the correction of microcirculatory disorders the methods are needed for both operative assessment of the state of blood flow at tissue level and for its long-term monitoring. The interest in the study of the microvascular bed of the circulatory system is sparked by the significant role of capillaries in the implementation of the basic processes of the body's vital activity, in the trophic support of organs and their direct participation in tissue and cellular respiration. The health and life expectancy of a person depend on the coordinated work of the heart, large blood lines, and microcirculation vessels. The authors have studied modern optical methods for diagnosing microcirculation. The feasibility of using the speckle imaging method for noninvasive rapid assessment of the state of the microvasculature of human surface biological tissues has been substantiated. To implement the speckle-visualization method, methodological and software have been developed. The processing parameters that are most optimal from the point of view of the ratio of spatiotemporal resolution and computation time have been experimentally substantiated. The purpose of this work is the experimental testing of the developed methodological and hardware speckle imaging for the diagnosis of microcirculation of human surface biological tissues. The authors have carried out the studies of the state of microcirculation in the superficial blood vessels of the skin during physiotherapeutic procedures and in the imitation of pathology. The results of the studies have proved the feasibility of using the developed software for a high-quality diagnosis of the state of microcirculation of human surface biological tissues: primary changes in microcirculation are revealed, further changes to occur during physiotherapeutic procedures are visualized.

Blood rheology is a challenging subject owing to the fact that blood is a mixture of a fluid (plasma) and of cells, among which red blood cells make about 50% of the total volume. It is precisely this circumstance that originates the peculiar behavior of blood flow in small vessels (i.e., roughly speaking, vessel with a diameter less than half a millimeter). In this class we find arterioles, venules, and capillaries. The phenomena taking place in microcirculation are very important in supporting life. Everybody knows the importance of blood filtration in kidneys, but other phenomena, of not less importance, are known only to a small class of physicians. Overviewing such subjects reveals the fascinating complexity of microcirculation.

To reveal the features of microcirculatory parameters in compensated and decompensated type 2 diabetes mellitus (T2DM).A total of 196 patients with T2DM were examined and divided into 2 groups: 1) 52 patients (40.4% of men) aged 52.8±8.7 years with compensated T2DM (glycated hemoglobin (HbA1с), 6.3±0.5%); 2) 68 patients (38.2% of men) aged 52.8±8.1 years with decompensated T2DM (HbA1с, 9.4±1.7%). Both patient groups had concomitant hypertension (its prevalence, degree, stage of hypertension were comparable). A control group consisted of 76 volunteers (40.8% of men) aged 52.2±8.7 years with normal carbohydrate metabolism and without signs of cardiovascular disease (HbA1с, 5.3±0.49%). Capillary blood flow in the finger nail-fold area was investigated in all the participants. A digital optical capillaroscope with image-processing software was used to obtain quantitative blood microcirculatory parameters. The diameters of arterial and venous capillary segments were measured, by calculating the remodeling rate. The degree of capillary tortuosity, network density, and polymorphism and the size of the perivascular zone (PZ) were estimated. Blood rheological properties and capillary blood flow velocity were also investigated.The decompensated T2DM group compared to the compensated T2DM group was found to have a narrowing of the arterial capillary segment diameter (8.4±2.0 µm; p=0.009) and an increase in remodeling rates (1.47±0.22; p=0.000). The tendency of the PZ size to be larger in patients with decompensated T2DM compared to those with compensated T2DM (p=0.080) and the increase in this indicator compared to the control group (p=0.001) reflect the presence of edema syndrome in Group 2, as laboratory confirmed by a statistically significantly elevated sodium level (p=0.000; p=0.006). The enlarged venous capillary segment demonstrates involvement of the venous component in microcirculatory disorders in T2DM. The reduction in the density of the capillary network and the increase in capillary tortuosity and polymorphism, which were also observed in the patients of both groups versus the control group, are referred to as disorders that are characteristic of T2DM.In decompensated T2DM, capillary bed structural and functional changes are found as a narrowing of the arterial capillary segment, an increase in the rate of remodeling, and enlargement of the PZ. Digital capillaroscopy opens up new possibilities for assessing the magnitude of changes in the microcirculatory system in DM and can simultaneously evaluate the efficiency of treatment, by monitoring the status of the microvasculature.Цель исследования. Выявить особенности параметров микроциркуляции при компенсированном и декомпенсированном сахарном диабете 2-го типа (СД-2). Материалы и методы. Обследовали 196 человек. Пациентов с СД-2 разделили на 2 группы: в 1-ю включили 52 пациентов с компенсированным СД-2 (52,8±8,7 года, 40,4% мужчин, уровень гликированного гемоглобина - HbA1с 6,3±0,5%), во 2-ю - 68 пациентов с декомпенсированным СД-2 (52,8±8,1 года, 38,2% мужчин, HbA1с 9,4±1,7%). В обеих группах у пациентов имелась сопутствующая артериальная гипертония - АГ (распространенность, степень, стадия АГ сопоставимы). Контрольную группу составили 76 добровольцев с нормальным углеводным обменом и без признаков сердечно-сосудистой патологии (52,2±8,70 года, 40,8% мужчин, HbA1с 5,3±0,49%). У всех участников исследовали капиллярный кровоток в области ногтевого ложа пальцев кисти. Применяли цифровой оптический капилляроскоп с использованием программы обработки изображений для получения количественных характеристик параметров микроциркуляции крови. Выполнены измерения диаметров в артериальном, венозном отделах капилляра с расчетом коэффициента ремоделирования. Оценены степень извитости, плотность сети, полиморфизм капилляров, величина периваскулярной зоны (ПЗ). Кроме того, исследованы реологические свойства крови, скорость капиллярного кровотока. Результаты. В группе пациентов с декомпенсированным СД-2 по сравнению с группой компенсированных по СД-2 больных выявлены сужение диаметра артериального отдела капилляра (8,4±2,0 мкм; р=0,009) и повышение коэффициента ремоделирования (1,47±0,22; р=0,000). Тенденция к увеличению размера ПЗ у пациентов с декомпенсированным СД-2 по сравнению с компенсированным (р=0,080) и увеличение этого показателя по сравнению с контрольной группой (р=0,001) отражают наличие отечного синдрома во 2-й группе, что лабораторно подтверждено статистически значимым повышением уровня натрия (р=0,000; р=0,006). Расширение венозного отдела капилляра демонстрирует участие венозного компонента в микроциркуляторных нарушениях при СД-2. Снижение плотности капиллярной сети, повышение извитости и полиморфизма капилляров, выявленные у пациентов обеих групп при сравнении с контрольной, относит их к нарушениям, характерным для СД-2. Заключение. При декомпенсации СД-2 выявлены структурные и функциональные изменения капиллярного русла в виде сужения артериального отдела капилляра, увеличения коэффициента ремоделирования, увеличения ПЗ. Цифровая капилляроскопия открывает новые возможности для оценки степени изменений в системе микроциркуляции при СД и одновременно позволяет оценить эффективность лечения, контролируя состояние микроциркуляторного русла.

Assessment of skin blood flow is an important clinical task which is required to study mechanisms of microcirculation regulation including thermoregulation. Contactless assessment of vasomotor reactivity in response to thermal exposure is currently not available. The aim of this study is to show the applicability of the imaging photoplethysmography (IPPG) method to measure quantitatively the vasomotor response to local thermal exposure. Seventeen healthy subjects aged 23 &plusmn, 7 years participated in the study. A warm transparent compress applied to subject&rsquo, s forehead served as a thermal impact. A custom-made IPPG system operating at green polarized light was used to monitor the subject&rsquo, s face continuously and simultaneously with skin temperature and electrocardiogram (ECG) recordings. We found that the thermal impact leads to an increase in the amplitude of blood pulsations (BPA) simultaneously with the skin temperature increase. However, a multiple increase in BPA remained after the compress was removed, whereas the skin temperature returned to the baseline. Moreover, the BPA increase and duration of the vasomotor response was associated with the degree of external heating. Therefore, the IPPG method allows us to quantify the parameters of capillary blood flow during local thermal exposure to the skin. This proposed technique of assessing the thermal reactivity of microcirculation can be applied for both clinical use and for biomedical research.

Intraoperative evaluation of blood perfusion in the brain cortex is an important but hitherto unresolved problem. Our aim was to demonstrate the feasibility of cerebral microcirculation assessment during open brain surgery by using camera-based photoplethysmography (cbPPG) synchronized with an electrocardiograph. Cortical blood flow was monitored in five patients with different diagnoses. Two cases (tumor resection and extra-intracranial bypass grafting) are presented in detail. Blood-flow parameters were visualized after processing cortex images recorded under green-light illumination before and after surgical intervention. In all cases, blood flow was successfully visualized in &gt, 95% of open brain. Distributions of blood pulsation amplitude, a parameter related to cortical blood perfusion, pulse arrival time, and blood-pressure-pulse shape were calculated with high spatial resolution (in every pixel). Changes in cerebral blood supply caused by surgical intervention were clearly revealed. We have shown that the temporal spread of pulse arrival time and the spatiotemporal variability of pulse shape are very sensitive markers of brain circulatory disturbances. The green-light cbPPG system offers a new approach to objective assessment of blood-flow changes in the brain during surgical intervention. The proposed system allows for contactless monitoring of cortex blood flow in real time with high resolution, thus providing useful information for surgery optimization and minimization of brain tissue damage.

The experimental research included the study of the functional state of blood microcirculation by means of laser Doppler flowmetry (LDF). It is allowed to assess the condition of tissue blood flow and to detect the early signs of changes in the microcirculation under the influence on breath-holding test. The obtained results showed that at most of students high-amplitude LDF with the expressed vasomotors` waves of the second order mainly was registered