Electron-conformational transformations in nanoscopic RyR channels govern both the heart's contraction and beating

We show that a simple biophysically based electron-conformational model of RyR channel is able to explain and describe on equal footing the oscillatory regime of the heart's cell release unit both in sinoatrial node (pacemaker) cells under normal physiological conditions and in ventricular myocytes under Ca$^{2+}$ SR overload.Comment: 6 pages, 3 figure

Classification Model of Heart Transplant Outcomes Based on Features of Left Ventricular Functional Geometry

The function of the transplanted heart can be significantly affected by acute allograft rejection, chronic rejection, high blood pressure. These factors may induce cardiac remodelling with further adverse consequences for the patients. Dynamic change in the configuration of the left ventricle (LV) from end diastole to end systole (LV functional geometry) is an important factor of the heart pump function. The objective of this study is to evaluate the time dependent changes in parameters of LV functional geometry in the transplanted heart and to assess relations between the changes and adverse outcomes of the heart transplantation (HT). We used linear discriminant analysis (LDA) to build classification models based on either the standard echocardiographic parameters of LV systolic function and global longitudinal strain (GLS) or LV function geometry indexes. The training set for model building included data from patients with different degrees of systolic dysfunction. Using the models, we retrospectively classified data from 31 patients after orthotropic HT. In contrast to the LDA models based on the standard echocardiographic characteristics and GLS, the model based on the LV functional geometry data showed high accuracy in predicting allograft rejection and development of the heart failure in the HT patients. © 2018 Creative Commons Attribution

The activated charcoal adsorption of phenol

The problems of treatment of the waste water were considered in this work. The main method of the activated charcoal adsorption of phenol was investigated. The adsorption properties of the adsorbent were also considered. Along with it Langmuir's and Friendlich's adsorption isotherm has been studied and analyzed

Role of myocardial properties and pacing lead location on ECG in personalized paced heart models

Personalised cardiac models were built from the computed tomography imaging data for two patients with implanted cardiac resynchronisation therapy devices. The cardiac models comprised a biventricular model of myocardial electrophysiology coupled with a model of the torso to simulate the body surface potential map. The models were verified against electrocardiogams (ECG) recorded in the patients from 240 leads on the body surface under left ventricular pacing. The simulated ECG demonstrated a significant sensitivity to the myocardial anisotropy and location of the pacing electrode tip in the models. An apicobasal cellular heterogeneity was shown to be less significant for the ECG pattern at the paced-ventricle activation than that showed earlier by Keller and co-authors (2012) for the normal activation sequence. © 2017 IEEE Computer Society. All rights reserved.This study was supported by the RAS Presidium Programme I.33Π, and Government of the Russian Federation (agreement 02.A03.21.0006). We used the computational clusters of Ural Federal University and ”URAN” of Institute of Mathematics and Mechanics (Ekaterinburg)

Integrative Modeling of Electrical Properties of Pacemaker Cardiac Cells

This work represents modeling of electrical properties of pacemaker (sinus) cardiac cells. Special attention is paid to electrical potential arising from transmembrane current of Na{+}, K{+} and Ca{2+} ions. This potential is calculated using the NaCaX model. In this respect, molar concentration of ions in the intercellular space which is calculated on the basis of the GENTEX model is essential. Combined use of two different models allows referring this approach to integrative modeling

Effects of Lead Position, Cardiac Rhythm Variation and Drug-induced QT Prolongation on Performance of Machine Learning Methods for ECG Processing

Machine learning shows great performance in various problems of electrocardiography (ECG) signal analysis. However, collecting a dataset for biomedical engineering is a very difficult task. Any dataset for ECG processing contains from 100 to 10,000 times fewer cases than datasets for image or text analysis. This issue is especially important because of physiological phenomena that can significantly change the morphology of heartbeats in ECG signals. In this preliminary study, we analyze the effects of lead choice from the standard ECG recordings, variation of ECG during 24-hours, and the effects of QT-prolongation agents on the performance of machine learning methods for ECG processing. We choose the problem of subject identification for analysis, because this problem may be solved for almost any available dataset of ECG data. In a discussion, we compare our findings with observations from other works that use machine learning for ECG processing with different problem statements. Our results show the importance of training dataset enrichment with ECG signals acquired in specific physiological conditions for obtaining good performance of ECG processing for real applications. © 2020 IEEE.The reported study was supported by RFBR research project No. 19-37-50079 and supported by the IIF UrB RAS theme №AAAA-A18-118020590031-8, RF Government Act #211 of March 16, 2013, the Program of the Presidium RAS

Electron-Conformational Transformations in Nanoscopic RyR Channels Governing Both the Heart's Contraction and Beating

We show that a simple biophysically based electron-conformational model of RyR channel can explain and describe on equal footing the oscillatory regime of the heart's cell release unit both in sinoatrial node (pacemaker) cells under normal physiological conditions and in ventricular myocytes under Ca2+ sarcoplasmic reticulum overload. © 2011 Pleiades Publishing, Ltd.This work was supported by the Ural Branch, Russian Academy of Sciences, project no. 09 M 14 2001

Аневризмы почечных артерий

Renal artery aneurysms are a rare condition and are usually found when other abdominal organ diseases are being searched. Among the causes of renal artery aneurysms, atherosclerosis and fibromuscular dysplasia predominate. However, they can also be observed in congenital Ehlers-Danlos syndrome, neurofibromatosis, arteritis, and due to traumatic effects. Most patients have an asymptomatic course of the disease. Literature data suggest slow growth of aneurysms, and their progression is associated with arterial hypertension, absence of wall calcification and pregnancy in young women. The aim of surgical treatment is to prevent aneurysm rupture, eliminate the risk of renal parenchyma embolism and correct arterial hypertension. Most authors believe that surgical treatment is indicated for asymptomatic course of the disease when the aneurysm is over 20 mm in diameter, aneurysm growth is over 5 mm within a year, arterial hypertension resistant to drug therapy, renal artery dissection and aneurysm presence in women of childbearing age. There are a number of surgical and endovascular techniques to restore renal blood flow. Both open and endovascular interventions are used for renal artery trunk surgery. For aneurysms of the renal artery branches, aortorenal shunting by autovenous or internal iliac artery as well as extracorporeal surgeries are more often used. The use of endografts is most appropriate for localization of aneurysms in the renal artery trunk, while embolization with microspirals and glue is most effective for saccular aneurysms. The embolization technique can cause embolization of the renal parenchyma itself as a potential complication, which aggravates arterial hypertension. The authors present the literature and their own data on various techniques to restore the renal blood flow. Up to 80-90% of the operated kidneys can be saved in the long term. Reconstructive surgery reduces the level of arterial pressure and reduces the number of antihypertensive drugs used and the need for renal replacement therapy.Аневризмы почечных артерий относятся к редким заболеваниям и, как правило, обнаруживаются при поиске других заболеваний органов брюшной полости. Среди причин возникновения аневризм почечных артерий преобладают атеросклероз и фиброзно-мышечная дисплазия. Однако они могут наблюдаться и при врожденном синдроме Элерса – Данлоса, нейрофиброматозе, артериитах и вследствие травматических воздействий. Большинство пациентов имеют асимптомное течение заболевания. Литературные данные свидетельствуют о медленном росте аневризм, а их прогрессирование связывают с артериальной гипертензией, отсутствием кальцификации стенки и беременностью у молодых женщин. Целью хирургического лечения являются профилактика разрыва аневризмы, устранение риска эмболии почечной паренхимы и коррекция артериальной гипертензии. Большинство авторов считают, что при асимптомном течении заболевания оперативное лечение показано при диаметре аневризмы более 20 мм, росте аневризмы более 5 мм в течение года, артериальной гипертензии, резистентной к медикаментозной терапии, диссекции почечной артерии и наличии аневризмы у женщин детородного возраста. Существует ряд хирургических и эндоваскулярных методик, позволяющих восстановить почечный кровоток. Для хирургии ствола почечной артерии используется методика как открытых, так и эндоваскулярных вмешательств. При аневризмах ветвей почечной артерии чаще используется аорторенальное шунтирование аутовеной или внутренней подвздошной артерией, а также экстракорпоральные операции. Использование эндографтов наиболее целесообразно при локализации аневризм в стволе почечной артерии, в то время как эмболизация микроспиралями и клеем наиболее эффективна при мешотчатых аневризмах. Методика эмболизации в качестве потенциальных осложнений может вызывать эмболию самой почечной паренхимы, что усугубляет артериальную гипертензию. В статье авторы приводят литературные и собственные данные о различных методиках восстановления почечного кровотока. В отдаленные сроки удается сохранить до 80–90% оперированных почек. Реконструктивные операции снижают уровень артериального давления и уменьшают количество использованных антигипертензивных препаратов и необходимость почечной заместительной терапии

Meshless electrophysiological modeling of cardiac resynchronization therapy—benchmark analysis with finite-element methods in experimental data

Computational models of cardiac electrophysiology are promising tools for reducing the rates of non-response patients suitable for cardiac resynchronization therapy (CRT) by optimizing electrode placement. The majority of computational models in the literature are mesh-based, primarily using the finite element method (FEM). The generation of patient-specific cardiac meshes has traditionally been a tedious task requiring manual intervention and hindering the modeling of a large number of cases. Meshless models can be a valid alternative due to their mesh quality independence. The organization of challenges such as the CRT-EPiggy19, providing unique experimental data as open access, enables benchmarking analysis of different cardiac computational modeling solutions with quantitative metrics. We present a benchmark analysis of a meshless-based method with finite-element methods for the prediction of cardiac electrical patterns in CRT, based on a subset of the CRT-EPiggy19 dataset. A data assimilation strategy was designed to personalize the most relevant parameters of the electrophysiological simulations and identify the optimal CRT lead configuration. The simulation results obtained with the meshless model were equivalent to FEM, with the most relevant aspect for accurate CRT predictions being the parameter personalization strategy (e.g., regional conduction velocity distribution, including the Purkinje system and CRT lead distribution). © 2022 by the authors. Licensee MDPI, Basel, Switzerland