Vitaliy Maksymenko - Academia.edu (original) (raw)
Papers by Vitaliy Maksymenko
Біомедична інженерія і технологія, 2021
Проблематика. Метод групового урахування аргументів є доволі недооціненим інструментом для отрима... more Проблематика. Метод групового урахування аргументів є доволі недооціненим інструментом для отримання високоточних прогностичних моделей. Перший варіант штучної нейронної мережі (які користуються величезною популярністю в світі машинного навчання) був отриманий в 1965 році українським вченим Олексієм Івахненко, який як раз використовував метод групового урахування аргументів для навчання мережі. Відомо, що даний підхід має місце фактично в будь-якій проблематиці, і не виключенням є задача розпізнавання ішемічної хвороби серця по відеоданим спекл-трекінг ехокардіографії. Вирішення подібної задачі є актуальним, оскільки це надасть можливість аналізувати ехокардіограми навіть якщо вони не оснащені технологією спекл-трекінг. Мета. Методом групового урахування аргументів за даними спекл-трекінг ехокардіографії побудувати класифікаційні алгоритми діагностики порушень кінематики скорочень лівого шлуночка серця у хворих на ішемічну хворобу серця в умовах стану спокою, та при застосуванні ехо...
Fiziolohichnyĭ zhurnal (Kiev, Ukraine : 1994), 2009
In the article a possibility of definition of level of the mitochondrial factor (MF) for early di... more In the article a possibility of definition of level of the mitochondrial factor (MF) for early diagnostics of the myocardial ischemic damages at patients during heart surgery was investigated. The reperfusion damages of heart were manifested by MPTP activation and MF release. The rising of MF level during a cardioplegia is comparable to level, which has been noted at patients with angina before operation of aorto-coronary shunting. The beginning of reperfusion, practically did not change MF level, but 5 minutes after restoration of a blood flow and warm reductions it increased to the maximum values. Thus, it closely correlated with a level of a myocardial contractility depression and data of biochemical researches, which are traditionally used in clinic for diagnostics of damages of a heart. It allows to confirm, what exactly reperfusion is a major factor damaging of a myocardium. Its important that, change of MF level we registered at first minutes of heart reperfusion, those are m...
Fiziolohichnyĭ zhurnal (Kiev, Ukraine : 1994), 1996
General properties of cardiovascular system functioning in the groups of postoperative patients i... more General properties of cardiovascular system functioning in the groups of postoperative patients in the cardiac surgery clinic were studied using the information technology (IT), combined the methods of cluster and nonlinear regression analysis and computer simulation. It was shown, that in all five separated groups of observations (clusters) the direct dependency of cardiac (CI) and stroke (SI) indexes on central venous pressure (CVP) was determined by the variations of total peripheral resistance and reactions of venous tone (u), contractility (E) and heart rate (HR), oriented on the stabilisation of mean aortic pressure (AP) on approximately the same level. Significant differences between the characteristics CI(CVP), SI(CVP) in the groups were determined by the level of E (especially of the right ventricle) and diastolic tone of the heart. Correlation of the cardiac (E,HR) and vascular (u) components of Ap regulation changed correspondingly the heart functional state. Proposed app...
International Journal of Physiology and Pathophysiology, 2014
Fiziolohichnyĭ zhurnal (Kiev, Ukraine : 1994), 2006
The model of ischemia/reperfusion was reproduced on 9 unconscious dogs. Simultaneously with regis... more The model of ischemia/reperfusion was reproduced on 9 unconscious dogs. Simultaneously with registration of indexes heart work, hemodynamic and mitochondrial factor (MF) in venous blood from right atrium was defined. Measures were done by spectrophotometria. We have also performed spectrophotometric determination of MF in 11 patients in course of operation with blood cardioplegia. Samples of mixed venous blood from the right atrium were taken on different stages of artificial blood circulation: ischemia and reperfusion. Besides that, patients' level of enzymes was defined: creatine kinase (CK), mv-creatine kinase (mv-CK), lactatedehydrogenase (LDG), aspartataminotransferase (AST), within first day of postoperative period, and also ECG-recording within pre- and after operative period were done. Maximal MF level correlates with frequency and severity of cardiac rhythm disturbance, severity of myocardial hypoxia (r = 0.81). Maximum MF level also demonstrated correlation with KK (r ...
The analysis of the urgent tasks of biomedical engineering is carried out andquestions are formul... more The analysis of the urgent tasks of biomedical engineering is carried out andquestions are formulated that need to be addressed at the state level, which will significantlyincrease the efficiency, safety and quality of healthcare, increase the profitability of operatingexpensive equipment, and will contribute to the revival of domestic production of medicalequipment and materials and the implementation of EU regulations.
Research Bulletin of the National Technical University of Ukraine "Kyiv Politechnic Institute", Dec 28, 2017
Background. Optic nerve head astrocytes (ONHAs) are the major glia cell type in the non-myelinate... more Background. Optic nerve head astrocytes (ONHAs) are the major glia cell type in the non-myelinated optic nerve head where they contribute to extracellular matrix synthesis. Pathological changes in glaucoma include reactive astrocytosis, a process characterized by altered astrocyte gene and protein expression and extracellular matrix remodeling. ONHAs are highly sensitive to mechanical and oxidative stress resulting in the initiation of axon damage early during pathogenesis. Furthermore, ONHAs are crucial for the maintenance of retinal ganglion cell physiology and function. Therefore, glioprotective strategies with the goal to preserve and/or restore the structural and functional viability of ONHA to slow glaucoma and related pathologies are of high clinical relevance. Objective. The aim of the paper is the development of standardized methods for the systematic advancement of glioprotective strategies using plate reader-based assays determining cellular viability, plate-reader based proliferation and the intracellular redox state. Methods. In our work we used primary culture of OHNAs as a model system. The oxidative stress was induced by tBHP. Reactive oxygen species (ROS) were measured by the DCDFA assay. For cell viability tests we used the optimized lactate dehydrogenase (LDH) release assay, as well as the MTT and Calcein-AM uptake assays. Results. The half-maximal effect (EC 50) of tBHP on OHNAs ROS levels in the DCFDA assay was 192.1 15.7 μM. The measurement of cellular viability of OHNAs after tBHP-induced oxidative stress showed EC 50 156.9 3.8 μM in the Calcein-AM uptake assay. In the MTT assay, the EC 50 for tBHP was 138.1 1.4 μM, and shifted to 192.7 2.8 μM with 100 μM Trolox pre-treatment of OHNA. In the LDH release assay, the EC 50 for tBHP was 146.9 4.9 μM and 246.3 7.3 μM for the control and Trolox conditions respectively. Conclusions. Our results provide feasibility data for the plate-reader based screening for novel glioprotectants using primary ONHA culture.
The article deals with the construction of the norm-pathology states classifiers according to sta... more The article deals with the construction of the norm-pathology states classifiers according to statistical features of the ultrasound images texture in diffuse liver diseases. A number of new features are proposed to distinguish the texture of classes. Classifiers are constructed in the form of analytical expressions using the GMDH Shell DS software and in the form of a forest, the trees of which are obtained in accordance with the GMDH principles. The work was performed on data, had provided by the Nuclear Medicine and Radiation Diagnostics Institute of the National Academy of Medical Sciences of Ukraine.
Background. The numerical heat transfer model for a system of myocardium coronary vessels is cons... more Background. The numerical heat transfer model for a system of myocardium coronary vessels is considered.Objective. The goal is to develop a discrete model for the physical system of myocardium and coronary vessels that would make it possible to explore the process of hypo- and hyperthermia with cardiopulmonary bypass.Methods. To solve the differential equation of heat conduction in the MSC Sinda thermal system the network method (TNM – Thermal Network Method) is used, in which system of heat equations is presented in the form of cellular-centered nodes and resistances between the nodes using the finite difference method. In constructing the model of myocardial in the MSC Sinda system the thermal contact between three-dimensional bodies is implemented – the myocardium, coronary arteries, a liquid cooling of heart.Results. Implementation of the model of heat exchange in the MSC Sinda system for infarction cooling process gives on the final process step in establishing the heat balance...
In this article a three-dimensional mathematical model of radiofrequency ablation during open-hea... more In this article a three-dimensional mathematical model of radiofrequency ablation during open-heart surgery is presented. It was developed to study temperature field distribution into myocardial tissue. This model uses an anatomically correct 3D model for the left atrium, obtained by magnetic resonance imaging (MRI) processing of a patient; takes into account thermoelectric characteristic differences depending on the area of electric current application; considers cooling by the air flow. An ex-vivo experiment on the pig's heart was performed where the depth of myocardium tissue damage was measured for the model validation. It was shown that the deviation of the model data from the experiment is within the limits of instrumental measurement error. The developed model is proposed to be used for heart ablation procedures planning, or new equipment development.
2020 IEEE 15th International Conference on Computer Sciences and Information Technologies (CSIT), 2020
The article deals with the construction of the norm-pathology states classifiers according to sta... more The article deals with the construction of the norm-pathology states classifiers according to statistical features of the ultrasound images texture in diffuse liver diseases. A number of new features are proposed to distinguish the texture of classes. Classifiers are constructed in the form of analytical expressions using the GMDH Shell DS software and in the form of a forest, the trees of which are obtained in accordance with the GMDH principles. The work was performed on data, had provided by the Nuclear Medicine and Radiation Diagnostics Institute of the National Academy of Medical Sciences of Ukraine.
The model for the physical system of myocardium and coronary vessels are realized on basis RC-the... more The model for the physical system of myocardium and coronary vessels are realized on basis RC-thermal network in the MSC Sinda system for the heat transfer model, which allows you to explore the process of hypo- and hyperthermia with cardiopulmonary bypass.
Purpose: Today radiofrequency heart ablation is gold standard for the radical surgical treatment ... more Purpose: Today radiofrequency heart ablation is gold standard for the radical surgical treatment of different types of heart rhythm disturbances.The purpose of the research is a comparative analysis of monopolar and bipolar electrodes for ablation during open heart surgery (Cox-Maze ablation). Methods: The analysis is made based on clinical data and mathematical modeling. By the use of system of electro-anatomical mapping of radiofrequency ablation zones a three-dimensional model of left atrium is created. Then a potential map, which represents the amplitude of myocardium activity, is imposed on this model. The amplitude of myocardium activity, the width and depth of the electro-thermal destruction zone and the ablation line continuity are main parameters of clinical data analysis. For mathematical modeling the COMSOL Multiphysics 5.4 software is used. Two variation of mathematical model for monopolar and bipolar ablation are created. Main analysis parameters of mathematical modelin...
Innovative Biosystems and Bioengineering, 2021
Background. Recent studies show that cardiovascular diseases, including coronary heart disease, a... more Background. Recent studies show that cardiovascular diseases, including coronary heart disease, are the leading causes of death and one of the main factors of disability worldwide. The detection of cases of this type of disease over the past 30 years has increased from 271 million to 523 million and the number of deaths – from 12.1 million to 18.6 million. Cardiovascular diseases are the main cause of death among the population of Ukraine and, according to this indicator, the country remains one of the world leaders. Coronary heart disease is the leading factor in the loss of health in Ukraine and modern diagnostic methods, including machine learning algorithms, are increasingly being used for timely detection. Objective. According to the data of speckle-tracking echocardiography using the random forest method, construct classification algorithms for diagnosing violations of the kinematics of left ventricular contractions in patients with coronary heart disease at rest, and when usi...
Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, 2016
Method of destruction of the pathological excitation sources in the heart by original monopolar e... more Method of destruction of the pathological excitation sources in the heart by original monopolar electrode. Purpose. This work is devoted to the study of destruction of the pathological excitation sources in the heart by the original monopolar electrode and the high-frequency electrosurgical generator Erbe VIO-100 S (Germany) in the coagulation mode in order to optimize technology of their using in surgical practice for Maze surgery. Methodology. Experimental study of the effect of electric current on the myocardium were performed in the laboratory on the endocardial part of four remote pig hearts in the cold hibernation state. Temperature evaluation of myocardial contact with the electrode was carried out using mathematical modeling of temperature fields of radio frequency current interaction with the tissue in the program Comsol Multiphysics. Results. Safe and effective destruction size, nature of histological and temperature changes in the interaction region of myocardial tissue with a source of electrical current depending on the duration and power application to stop the spread of pathological excitation sources in the heart were defined. Originality. The recommendations on the choice of the optimal parameters for the application of the generator Erbe and the original monopolar electrode were developed and adapted to radiofrequency ablation of myocardial tissue in the open heart for the arrhythmias treatment in order to reduce the total duration of surgery with cardiopulmonary bypass. Practical value. The results have been introduced in surgical practice of the State Institution «M.M. Amosov National Institute of Cardiovascular Surgery Ukraine NAMS of Ukraine». The work has great practical importance, because the expanding of the functional range of generator Erbe VIO-100 S (Germany) applications and reducing of the cost of radio frequency ablation procedure in comparison with the use of specialized disposable bipolar electrodes.
Kibernetika i vyčislitelʹnaâ tehnika, 2019
THE METHOD OF DETERMINING CONDUCTIBILITY FOR CORONARY VESSELS BY TERMOGRAPHY Introduction. The ch... more THE METHOD OF DETERMINING CONDUCTIBILITY FOR CORONARY VESSELS BY TERMOGRAPHY Introduction. The character of the distribution of temperature in the heart is determined by the process of heat exchange between the myocardium and coronary vessels, as well as the state of microhemodynamics of the coronary vessels of the heart. For quantitative estimation of changes in temperature distribution on the surface of the heart, the algorithm for calculating a quantitative criterion, that may be an objective marker for effective protection of the heart and brain, is proposed. The method of determining the conductibity of coronary vessels is implemented on the basis of the algorithm for determining the thermal contours, calculated from the gradients of the temperature field on the image of the heart in the infrared spectrum. The improvement of the previously developed method for determining the thermal contours on the basis of Canny's algorithm consists of the transition from qualitative to quantitative assessment of the rate of change in temperature on the surface of the myocardium. The purpose of this study is to evaluate the conductibity of coronary vessels for the study of blood flow in the surface layer of the myocardium during warming up and cooling of the heart in conditions of cardiopulmonary bypass. Results. The numerical value of the quantitative criterion obtained is calculated by determining the difference in temperature between the blood and the myocardium, calculated as the difference between the geometric areas under the temperature distribution curves in the temperature field equation for the constant and the current fluxing temperature. The contouring method for determining the conductibity of coronary vessels allows to select areas on the surface of the myocardium, in which the change in temperature significantly lags behind the average temperature on the surface during warming or cooling of the heart, which indirectly allows evaluating the state of small coronary vessels in the myocardium.
Journal of Cardiology & Current Research, 2017
Intraoperative infrared thermography (IRT) of the heart attracted the attention of scientists and... more Intraoperative infrared thermography (IRT) of the heart attracted the attention of scientists and clinicians for many years. IRT thermography of the heart in the experiments confirmed the importance of the diagnostic information obtained. The aim was expansion of available information about protection of the myocardium and the state of its vascular bed using heat transfer model based on the pericardial temperature propagation in circumstances of CPB.
Research Bulletin of the National Technical University of Ukraine "Kyiv Politechnic Institute", 2017
Background. The numerical heat transfer model for a system of myocardium coronary vessels is cons... more Background. The numerical heat transfer model for a system of myocardium coronary vessels is considered. Objective. The goal is to develop a discrete model for the physical system of myocardium and coronary vessels that would make it possible to explore the process of hypo-and hyperthermia with cardiopulmonary bypass. Methods. To solve the differential equation of heat conduction in the MSC Sinda thermal system the network method (TNM-Thermal Network Method) is used, in which system of heat equations is presented in the form of cellular-centered nodes and resistances between the nodes using the finite difference method. In constructing the model of myocardial in the MSC Sinda system the thermal contact between three-dimensional bodies is implementedthe myocardium, coronary arteries, a liquid cooling of heart. Results. Implementation of the model of heat exchange in the MSC Sinda system for infarction cooling process gives on the final process step in establishing the heat balance the temperature difference at the boundary between the myocardium and coronary vessels not more than 0,5 C. However, in the areas of the myocardium that are removed from the coronary vessels the temperature difference exceeds 1,0 C. The use of additional cooling for hearts allows for the cooling of myocardium with using of ice surface, that provides the unevenness reduction of the heart temperature during its cooling with cardiopulmonary bypass. This result allows exploring the dynamics of the process of hypo-and hyperthermia with cardiopulmonary bypass. Conclusions. The discrete 3D-model of heat transfer in the layer structure of the myocardium and coronary vessels allows us to investigate the process of hypo-and hyperthermia with cardiopulmonary bypass. The simulation results also make it possible to perform the analysis of the temperature distribution on the surface of the myocardium provided free convection of heat between the layers.
2015 IEEE 35th International Conference on Electronics and Nanotechnology (ELNANO), 2015
The work is devoted to research of catheter radiofrequency ablation modes (CRFA) in the treatment... more The work is devoted to research of catheter radiofrequency ablation modes (CRFA) in the treatment of the heart pathways disease. Lesions sizes of myocardial tissue during CRFA have been obtained in the experiment depending on output of the generator power, the electrode temperature, the size of electrode tip, duration of RF exposure. The work gives suggestions for optimal catheter radiofrequency ablation modes.
2015 IEEE 35th International Conference on Electronics and Nanotechnology (ELNANO), 2015
The possibility of noninvasive localization of the focus of ectopic ventricular activity and depe... more The possibility of noninvasive localization of the focus of ectopic ventricular activity and dependence of its accuracy on the used heart and torso model were examined. Body surface potentials were measured in 62 leads in two patients with idiopathic extrasystoles having the focus in different ventricular regions assessed by intracardiac electrophysiological study. Integral maps over the initial period of the premature ventricular activation and inhomogeneous torso model were used as input for an inverse solution to find noninvasively the focus of the premature activation represented by a single dipole. Three torso models representing the individual patient torso with different fidelity were attempted. The best agreement between the focus positions obtained from the inverse solution and from the electrophysiological study was achieved when the torso and heart model based on whole-torso CT was used. The use of an individually adjusted general torso model and properly positioned heart model obtained from CT gave less accurate but still acceptable location of the ectopic focus. If the same adjusted general torso model was used with simplified geometric heart model, the fidelity of its shape and position significantly influenced the inverse solution and the results varied from acceptable focus locations to locations scattered in a wide range of the ventricular volume. From the obtained results it can be presumed that by inverse solution based on dipolar cardiac generator model, measured body surface potential maps and CT-based torso model the initial location of the ectopic premature activity can be obtained. In addition, if the whole-torso CT is not available a model with a general torso shape adjusted to patient chest dimensions and with properly positioned heart model based on CT-scan of the heart area can still give acceptable location of the ectopic activity.
Біомедична інженерія і технологія, 2021
Проблематика. Метод групового урахування аргументів є доволі недооціненим інструментом для отрима... more Проблематика. Метод групового урахування аргументів є доволі недооціненим інструментом для отримання високоточних прогностичних моделей. Перший варіант штучної нейронної мережі (які користуються величезною популярністю в світі машинного навчання) був отриманий в 1965 році українським вченим Олексієм Івахненко, який як раз використовував метод групового урахування аргументів для навчання мережі. Відомо, що даний підхід має місце фактично в будь-якій проблематиці, і не виключенням є задача розпізнавання ішемічної хвороби серця по відеоданим спекл-трекінг ехокардіографії. Вирішення подібної задачі є актуальним, оскільки це надасть можливість аналізувати ехокардіограми навіть якщо вони не оснащені технологією спекл-трекінг. Мета. Методом групового урахування аргументів за даними спекл-трекінг ехокардіографії побудувати класифікаційні алгоритми діагностики порушень кінематики скорочень лівого шлуночка серця у хворих на ішемічну хворобу серця в умовах стану спокою, та при застосуванні ехо...
Fiziolohichnyĭ zhurnal (Kiev, Ukraine : 1994), 2009
In the article a possibility of definition of level of the mitochondrial factor (MF) for early di... more In the article a possibility of definition of level of the mitochondrial factor (MF) for early diagnostics of the myocardial ischemic damages at patients during heart surgery was investigated. The reperfusion damages of heart were manifested by MPTP activation and MF release. The rising of MF level during a cardioplegia is comparable to level, which has been noted at patients with angina before operation of aorto-coronary shunting. The beginning of reperfusion, practically did not change MF level, but 5 minutes after restoration of a blood flow and warm reductions it increased to the maximum values. Thus, it closely correlated with a level of a myocardial contractility depression and data of biochemical researches, which are traditionally used in clinic for diagnostics of damages of a heart. It allows to confirm, what exactly reperfusion is a major factor damaging of a myocardium. Its important that, change of MF level we registered at first minutes of heart reperfusion, those are m...
Fiziolohichnyĭ zhurnal (Kiev, Ukraine : 1994), 1996
General properties of cardiovascular system functioning in the groups of postoperative patients i... more General properties of cardiovascular system functioning in the groups of postoperative patients in the cardiac surgery clinic were studied using the information technology (IT), combined the methods of cluster and nonlinear regression analysis and computer simulation. It was shown, that in all five separated groups of observations (clusters) the direct dependency of cardiac (CI) and stroke (SI) indexes on central venous pressure (CVP) was determined by the variations of total peripheral resistance and reactions of venous tone (u), contractility (E) and heart rate (HR), oriented on the stabilisation of mean aortic pressure (AP) on approximately the same level. Significant differences between the characteristics CI(CVP), SI(CVP) in the groups were determined by the level of E (especially of the right ventricle) and diastolic tone of the heart. Correlation of the cardiac (E,HR) and vascular (u) components of Ap regulation changed correspondingly the heart functional state. Proposed app...
International Journal of Physiology and Pathophysiology, 2014
Fiziolohichnyĭ zhurnal (Kiev, Ukraine : 1994), 2006
The model of ischemia/reperfusion was reproduced on 9 unconscious dogs. Simultaneously with regis... more The model of ischemia/reperfusion was reproduced on 9 unconscious dogs. Simultaneously with registration of indexes heart work, hemodynamic and mitochondrial factor (MF) in venous blood from right atrium was defined. Measures were done by spectrophotometria. We have also performed spectrophotometric determination of MF in 11 patients in course of operation with blood cardioplegia. Samples of mixed venous blood from the right atrium were taken on different stages of artificial blood circulation: ischemia and reperfusion. Besides that, patients' level of enzymes was defined: creatine kinase (CK), mv-creatine kinase (mv-CK), lactatedehydrogenase (LDG), aspartataminotransferase (AST), within first day of postoperative period, and also ECG-recording within pre- and after operative period were done. Maximal MF level correlates with frequency and severity of cardiac rhythm disturbance, severity of myocardial hypoxia (r = 0.81). Maximum MF level also demonstrated correlation with KK (r ...
The analysis of the urgent tasks of biomedical engineering is carried out andquestions are formul... more The analysis of the urgent tasks of biomedical engineering is carried out andquestions are formulated that need to be addressed at the state level, which will significantlyincrease the efficiency, safety and quality of healthcare, increase the profitability of operatingexpensive equipment, and will contribute to the revival of domestic production of medicalequipment and materials and the implementation of EU regulations.
Research Bulletin of the National Technical University of Ukraine "Kyiv Politechnic Institute", Dec 28, 2017
Background. Optic nerve head astrocytes (ONHAs) are the major glia cell type in the non-myelinate... more Background. Optic nerve head astrocytes (ONHAs) are the major glia cell type in the non-myelinated optic nerve head where they contribute to extracellular matrix synthesis. Pathological changes in glaucoma include reactive astrocytosis, a process characterized by altered astrocyte gene and protein expression and extracellular matrix remodeling. ONHAs are highly sensitive to mechanical and oxidative stress resulting in the initiation of axon damage early during pathogenesis. Furthermore, ONHAs are crucial for the maintenance of retinal ganglion cell physiology and function. Therefore, glioprotective strategies with the goal to preserve and/or restore the structural and functional viability of ONHA to slow glaucoma and related pathologies are of high clinical relevance. Objective. The aim of the paper is the development of standardized methods for the systematic advancement of glioprotective strategies using plate reader-based assays determining cellular viability, plate-reader based proliferation and the intracellular redox state. Methods. In our work we used primary culture of OHNAs as a model system. The oxidative stress was induced by tBHP. Reactive oxygen species (ROS) were measured by the DCDFA assay. For cell viability tests we used the optimized lactate dehydrogenase (LDH) release assay, as well as the MTT and Calcein-AM uptake assays. Results. The half-maximal effect (EC 50) of tBHP on OHNAs ROS levels in the DCFDA assay was 192.1 15.7 μM. The measurement of cellular viability of OHNAs after tBHP-induced oxidative stress showed EC 50 156.9 3.8 μM in the Calcein-AM uptake assay. In the MTT assay, the EC 50 for tBHP was 138.1 1.4 μM, and shifted to 192.7 2.8 μM with 100 μM Trolox pre-treatment of OHNA. In the LDH release assay, the EC 50 for tBHP was 146.9 4.9 μM and 246.3 7.3 μM for the control and Trolox conditions respectively. Conclusions. Our results provide feasibility data for the plate-reader based screening for novel glioprotectants using primary ONHA culture.
The article deals with the construction of the norm-pathology states classifiers according to sta... more The article deals with the construction of the norm-pathology states classifiers according to statistical features of the ultrasound images texture in diffuse liver diseases. A number of new features are proposed to distinguish the texture of classes. Classifiers are constructed in the form of analytical expressions using the GMDH Shell DS software and in the form of a forest, the trees of which are obtained in accordance with the GMDH principles. The work was performed on data, had provided by the Nuclear Medicine and Radiation Diagnostics Institute of the National Academy of Medical Sciences of Ukraine.
Background. The numerical heat transfer model for a system of myocardium coronary vessels is cons... more Background. The numerical heat transfer model for a system of myocardium coronary vessels is considered.Objective. The goal is to develop a discrete model for the physical system of myocardium and coronary vessels that would make it possible to explore the process of hypo- and hyperthermia with cardiopulmonary bypass.Methods. To solve the differential equation of heat conduction in the MSC Sinda thermal system the network method (TNM – Thermal Network Method) is used, in which system of heat equations is presented in the form of cellular-centered nodes and resistances between the nodes using the finite difference method. In constructing the model of myocardial in the MSC Sinda system the thermal contact between three-dimensional bodies is implemented – the myocardium, coronary arteries, a liquid cooling of heart.Results. Implementation of the model of heat exchange in the MSC Sinda system for infarction cooling process gives on the final process step in establishing the heat balance...
In this article a three-dimensional mathematical model of radiofrequency ablation during open-hea... more In this article a three-dimensional mathematical model of radiofrequency ablation during open-heart surgery is presented. It was developed to study temperature field distribution into myocardial tissue. This model uses an anatomically correct 3D model for the left atrium, obtained by magnetic resonance imaging (MRI) processing of a patient; takes into account thermoelectric characteristic differences depending on the area of electric current application; considers cooling by the air flow. An ex-vivo experiment on the pig's heart was performed where the depth of myocardium tissue damage was measured for the model validation. It was shown that the deviation of the model data from the experiment is within the limits of instrumental measurement error. The developed model is proposed to be used for heart ablation procedures planning, or new equipment development.
2020 IEEE 15th International Conference on Computer Sciences and Information Technologies (CSIT), 2020
The article deals with the construction of the norm-pathology states classifiers according to sta... more The article deals with the construction of the norm-pathology states classifiers according to statistical features of the ultrasound images texture in diffuse liver diseases. A number of new features are proposed to distinguish the texture of classes. Classifiers are constructed in the form of analytical expressions using the GMDH Shell DS software and in the form of a forest, the trees of which are obtained in accordance with the GMDH principles. The work was performed on data, had provided by the Nuclear Medicine and Radiation Diagnostics Institute of the National Academy of Medical Sciences of Ukraine.
The model for the physical system of myocardium and coronary vessels are realized on basis RC-the... more The model for the physical system of myocardium and coronary vessels are realized on basis RC-thermal network in the MSC Sinda system for the heat transfer model, which allows you to explore the process of hypo- and hyperthermia with cardiopulmonary bypass.
Purpose: Today radiofrequency heart ablation is gold standard for the radical surgical treatment ... more Purpose: Today radiofrequency heart ablation is gold standard for the radical surgical treatment of different types of heart rhythm disturbances.The purpose of the research is a comparative analysis of monopolar and bipolar electrodes for ablation during open heart surgery (Cox-Maze ablation). Methods: The analysis is made based on clinical data and mathematical modeling. By the use of system of electro-anatomical mapping of radiofrequency ablation zones a three-dimensional model of left atrium is created. Then a potential map, which represents the amplitude of myocardium activity, is imposed on this model. The amplitude of myocardium activity, the width and depth of the electro-thermal destruction zone and the ablation line continuity are main parameters of clinical data analysis. For mathematical modeling the COMSOL Multiphysics 5.4 software is used. Two variation of mathematical model for monopolar and bipolar ablation are created. Main analysis parameters of mathematical modelin...
Innovative Biosystems and Bioengineering, 2021
Background. Recent studies show that cardiovascular diseases, including coronary heart disease, a... more Background. Recent studies show that cardiovascular diseases, including coronary heart disease, are the leading causes of death and one of the main factors of disability worldwide. The detection of cases of this type of disease over the past 30 years has increased from 271 million to 523 million and the number of deaths – from 12.1 million to 18.6 million. Cardiovascular diseases are the main cause of death among the population of Ukraine and, according to this indicator, the country remains one of the world leaders. Coronary heart disease is the leading factor in the loss of health in Ukraine and modern diagnostic methods, including machine learning algorithms, are increasingly being used for timely detection. Objective. According to the data of speckle-tracking echocardiography using the random forest method, construct classification algorithms for diagnosing violations of the kinematics of left ventricular contractions in patients with coronary heart disease at rest, and when usi...
Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia, 2016
Method of destruction of the pathological excitation sources in the heart by original monopolar e... more Method of destruction of the pathological excitation sources in the heart by original monopolar electrode. Purpose. This work is devoted to the study of destruction of the pathological excitation sources in the heart by the original monopolar electrode and the high-frequency electrosurgical generator Erbe VIO-100 S (Germany) in the coagulation mode in order to optimize technology of their using in surgical practice for Maze surgery. Methodology. Experimental study of the effect of electric current on the myocardium were performed in the laboratory on the endocardial part of four remote pig hearts in the cold hibernation state. Temperature evaluation of myocardial contact with the electrode was carried out using mathematical modeling of temperature fields of radio frequency current interaction with the tissue in the program Comsol Multiphysics. Results. Safe and effective destruction size, nature of histological and temperature changes in the interaction region of myocardial tissue with a source of electrical current depending on the duration and power application to stop the spread of pathological excitation sources in the heart were defined. Originality. The recommendations on the choice of the optimal parameters for the application of the generator Erbe and the original monopolar electrode were developed and adapted to radiofrequency ablation of myocardial tissue in the open heart for the arrhythmias treatment in order to reduce the total duration of surgery with cardiopulmonary bypass. Practical value. The results have been introduced in surgical practice of the State Institution «M.M. Amosov National Institute of Cardiovascular Surgery Ukraine NAMS of Ukraine». The work has great practical importance, because the expanding of the functional range of generator Erbe VIO-100 S (Germany) applications and reducing of the cost of radio frequency ablation procedure in comparison with the use of specialized disposable bipolar electrodes.
Kibernetika i vyčislitelʹnaâ tehnika, 2019
THE METHOD OF DETERMINING CONDUCTIBILITY FOR CORONARY VESSELS BY TERMOGRAPHY Introduction. The ch... more THE METHOD OF DETERMINING CONDUCTIBILITY FOR CORONARY VESSELS BY TERMOGRAPHY Introduction. The character of the distribution of temperature in the heart is determined by the process of heat exchange between the myocardium and coronary vessels, as well as the state of microhemodynamics of the coronary vessels of the heart. For quantitative estimation of changes in temperature distribution on the surface of the heart, the algorithm for calculating a quantitative criterion, that may be an objective marker for effective protection of the heart and brain, is proposed. The method of determining the conductibity of coronary vessels is implemented on the basis of the algorithm for determining the thermal contours, calculated from the gradients of the temperature field on the image of the heart in the infrared spectrum. The improvement of the previously developed method for determining the thermal contours on the basis of Canny's algorithm consists of the transition from qualitative to quantitative assessment of the rate of change in temperature on the surface of the myocardium. The purpose of this study is to evaluate the conductibity of coronary vessels for the study of blood flow in the surface layer of the myocardium during warming up and cooling of the heart in conditions of cardiopulmonary bypass. Results. The numerical value of the quantitative criterion obtained is calculated by determining the difference in temperature between the blood and the myocardium, calculated as the difference between the geometric areas under the temperature distribution curves in the temperature field equation for the constant and the current fluxing temperature. The contouring method for determining the conductibity of coronary vessels allows to select areas on the surface of the myocardium, in which the change in temperature significantly lags behind the average temperature on the surface during warming or cooling of the heart, which indirectly allows evaluating the state of small coronary vessels in the myocardium.
Journal of Cardiology & Current Research, 2017
Intraoperative infrared thermography (IRT) of the heart attracted the attention of scientists and... more Intraoperative infrared thermography (IRT) of the heart attracted the attention of scientists and clinicians for many years. IRT thermography of the heart in the experiments confirmed the importance of the diagnostic information obtained. The aim was expansion of available information about protection of the myocardium and the state of its vascular bed using heat transfer model based on the pericardial temperature propagation in circumstances of CPB.
Research Bulletin of the National Technical University of Ukraine "Kyiv Politechnic Institute", 2017
Background. The numerical heat transfer model for a system of myocardium coronary vessels is cons... more Background. The numerical heat transfer model for a system of myocardium coronary vessels is considered. Objective. The goal is to develop a discrete model for the physical system of myocardium and coronary vessels that would make it possible to explore the process of hypo-and hyperthermia with cardiopulmonary bypass. Methods. To solve the differential equation of heat conduction in the MSC Sinda thermal system the network method (TNM-Thermal Network Method) is used, in which system of heat equations is presented in the form of cellular-centered nodes and resistances between the nodes using the finite difference method. In constructing the model of myocardial in the MSC Sinda system the thermal contact between three-dimensional bodies is implementedthe myocardium, coronary arteries, a liquid cooling of heart. Results. Implementation of the model of heat exchange in the MSC Sinda system for infarction cooling process gives on the final process step in establishing the heat balance the temperature difference at the boundary between the myocardium and coronary vessels not more than 0,5 C. However, in the areas of the myocardium that are removed from the coronary vessels the temperature difference exceeds 1,0 C. The use of additional cooling for hearts allows for the cooling of myocardium with using of ice surface, that provides the unevenness reduction of the heart temperature during its cooling with cardiopulmonary bypass. This result allows exploring the dynamics of the process of hypo-and hyperthermia with cardiopulmonary bypass. Conclusions. The discrete 3D-model of heat transfer in the layer structure of the myocardium and coronary vessels allows us to investigate the process of hypo-and hyperthermia with cardiopulmonary bypass. The simulation results also make it possible to perform the analysis of the temperature distribution on the surface of the myocardium provided free convection of heat between the layers.
2015 IEEE 35th International Conference on Electronics and Nanotechnology (ELNANO), 2015
The work is devoted to research of catheter radiofrequency ablation modes (CRFA) in the treatment... more The work is devoted to research of catheter radiofrequency ablation modes (CRFA) in the treatment of the heart pathways disease. Lesions sizes of myocardial tissue during CRFA have been obtained in the experiment depending on output of the generator power, the electrode temperature, the size of electrode tip, duration of RF exposure. The work gives suggestions for optimal catheter radiofrequency ablation modes.
2015 IEEE 35th International Conference on Electronics and Nanotechnology (ELNANO), 2015
The possibility of noninvasive localization of the focus of ectopic ventricular activity and depe... more The possibility of noninvasive localization of the focus of ectopic ventricular activity and dependence of its accuracy on the used heart and torso model were examined. Body surface potentials were measured in 62 leads in two patients with idiopathic extrasystoles having the focus in different ventricular regions assessed by intracardiac electrophysiological study. Integral maps over the initial period of the premature ventricular activation and inhomogeneous torso model were used as input for an inverse solution to find noninvasively the focus of the premature activation represented by a single dipole. Three torso models representing the individual patient torso with different fidelity were attempted. The best agreement between the focus positions obtained from the inverse solution and from the electrophysiological study was achieved when the torso and heart model based on whole-torso CT was used. The use of an individually adjusted general torso model and properly positioned heart model obtained from CT gave less accurate but still acceptable location of the ectopic focus. If the same adjusted general torso model was used with simplified geometric heart model, the fidelity of its shape and position significantly influenced the inverse solution and the results varied from acceptable focus locations to locations scattered in a wide range of the ventricular volume. From the obtained results it can be presumed that by inverse solution based on dipolar cardiac generator model, measured body surface potential maps and CT-based torso model the initial location of the ectopic premature activity can be obtained. In addition, if the whole-torso CT is not available a model with a general torso shape adjusted to patient chest dimensions and with properly positioned heart model based on CT-scan of the heart area can still give acceptable location of the ectopic activity.