Machine learning aids clinical decision making in patients presenting with angina and non-obstructive coronary artery disease

Aims The current gold-standard comprehensive assessment of coronary microvascular dysfunction (CMD) is through a limited-access invasive catheterization lab procedure. We aimed to develop a point-of-care tool to assist clinical guidance in patients presenting with chest pain and/or an abnormal cardiac functional stress test and with non-obstructive coronary artery disease (NOCAD). Methods and Results This study included 1,893 NOCAD patients (<50% angiographic stenosis) who underwent CMD evaluation as well as an ECG up to 1-year prior. Endothelial-independent CMD was defined by coronary flow reserve (CFR)≤2.5 in response to intracoronary adenosine. Endothelial-dependent CMD was defined by a maximal percent increase in coronary blood flow (%ΔCBF) ≤50% in response to intracoronary acetylcholine infusion. We trained algorithms to distinguish between the following outcomes: CFR ≤ 2.5, %ΔCBF ≤ 50, and the combination of both. Two classes of algorithms were trained, one depending on ECG waveforms as input, and another using tabular clinical data. Mean age was 51 ± 12 years and 66% were females (n = 1,257). AUC values ranged from 0.49–0.67 for all the outcomes. The best performance in our analysis was for the outcome CFR ≤ 2.5 with clinical variables. AUC and accuracy were 0.67 and 60%. When decreasing the threshold of positivity, sensitivity and NPV increased to 92% and 90% respectively, while specificity and PPV decreased to 25% and 29% respectively. Conclusion An AI-enabled algorithm may be able to assist clinical guidance by ruling out CMD in patients presenting with chest pain and/or an abnormal functional stress test. This algorithm needs to be prospectively validated in different cohorts.

Extracytoplasmic Function σ Factors as Tools for Coordinating Stress Responses

The ability of bacterial core RNA polymerase (RNAP) to interact with different σ factors, thereby forming a variety of holoenzymes with different specificities, represents a powerful tool to coordinately reprogram gene expression. Extracytoplasmic function σ factors (ECFs), which are the largest and most diverse family of alternative σ factors, frequently participate in stress responses. The classification of ECFs in 157 different groups according to their phylogenetic relationships and genomic context has revealed their diversity. Here, we have clustered 55 ECF groups with experimentally studied representatives into two broad classes of stress responses. The remaining 102 groups still lack any mechanistic or functional insight, representing a myriad of systems yet to explore. In this work, we review the main features of ECFs and discuss the different mechanisms controlling their production and activity, and how they lead to a functional stress response. Finally, we focus in more detail on two well-characterized ECFs, for which the mechanisms to detect and respond to stress are complex and completely different: Escherichia coli RpoE, which is the best characterized ECF and whose structural and functional studies have provided key insights into the transcription initiation by ECF-RNAP holoenzymes, and the ECF15-type EcfG, the master regulator of the general stress response in Alphaproteobacteria.

Assessment of heart rate variability and adaptive capacity in children with type I diabetes

Annotation. Heart damage in type I diabetes in children is an understudied and at the same time dangerous complication. The aim of the study was to examine heart rate variability (HRV) and changes in adaptive capacity in children with type 1 diabetes mellitus (DM) depending on the duration of the disease. 38 children (16 boys and 22 girls) aged 6 to 17 years with type I diabetes were examined. Daily ECG monitoring with HRV analysis using the software and hardware complex “DiaCard-1” and the program “CardioBiorhythm” (JSC Solveig, Kyiv) was performed. Indicators of statistical (time domain) and spectral (frequency domain) analysis were evaluated: Mean, SDNN-i, rMSSD, pNN50, IN, AMо, VLF, LF, HF, LF/HF, activity index of regulatory systems. All children with type I diabetes had a statistically significant decrease in the mean values of Mean, SDNN-i, pNN50 (and in girls rMSSD and SDANN) and increased tension index (Baevsky) and fashion amplitude (AMo). Correlation analysis of all cases (Spearman's rank correlation) revealed a correlation between IN and AMo with the duration of the disease. PARS significantly exceed the limits of physiological values. It is established that the vast majority of patients in both groups are in a state of functional stress of adaptive capacity. With increasing duration of the disease, heart rate increases, parasympathetic and sympathetic influences weaken, the tension of adaptive mechanisms increases, the function of heart rate scattering weakens and the function of rhythm concentration increases, which indicates the transformation of functional autonomic disorders into autonomic. Thus, in children with type I diabetes mellitus, a progressive decrease in heart rate variability, progressive lesion of the parasympathetic link of the VNS, decrease in heart rate dislocation function and increase in rhythm concentration function and functional stress of adaptive mechanisms are determined.

PSYCHOPHYSIOLOGICAL STATUS OF MEN AND WOMEN IN COMBAT SPORTS

Aim. The article aims to assess the psychophysiological characteristics of skilled athletes in combat sports (boxing, freestyle wrestling, judo). Materials and methods. 18–23-year-old skilled combat athletes were examined. All athletes were divided into the following groups: the first group - female athletes (n = 15); the second group - male athletes (n = 17); the third and fourth groups - control groups consisted of males and females of the same age and not involved in sports (15 people each). The following methods were used: a pulse measurement, psychological tests, self-assessment of the psychoemotional status, electroencephalography, cardiointervalography with the calculation of statistical indicators of heart rate. Examinations were performed before and after the relaxation exercise, which was a three-minute concentration of attention at a specific point on the body. Results. The results revealed that female athletes had lower indicators of psychoemotional status than males but higher than untrained females. The indicators of psychoemotional stress were lower in female athletes than in male athletes and untrained women. For example, the indicator of personal anxiety in female athletes was 41.0 ± 1.8 versus 47.2 ± 2.5 in untrained women (P < 0.05). In female athletes, heart rate, the amplitude of the mode and voltage index (77.15 ± 2.05) in the structure of heart rate were slightly higher than in males (73.10 ± ± 1.07), which indicated greater functional stress of the heart. Relaxation led to favorable changes in EEG indicators and decreased functional stress of the heart in all subjects. Conclusion. It is recommended to extend the terms of sports training in female combat athletes to ensure a smooth transition to sports specialization and reduce injuries.

Evaluation of the functional tension of foreign medical student’s organisms in adapting to educational activities

The use of mathematical modeling methods allowed us to develop criteria for functional stress for assessing and predicting the level of functional stress of foreign students in the process of adaptation to the educational process.

NEUROPHYSIOLOGICAL MECHANISMS OF LOGONEUROSIS IN PRESCHOOL CHILDREN DURING FUNCTIONAL STRESS

The changes in the electrical activity of the brain of boys with different tempo-rhythmic characteristics of speech during functional stress have been studied, namely, a series of flashes of light of a certain frequency – rhythmic photostimulation have been used. The bioelectrical activity of the brain has been studied using a computer electroencephalography system. Also, according to the methodology of zonal distribution of normalized spectral power (SP) of the rhythm of the main frequency of the EEGranges, the particles (in percent) of the normalized SP of electrogenesis in each of the four main ranges (δ, θ, α, β) have been determined. As a result of comparison of the light flashing frequency assimilation among boys in the studied groups, it has been found, that in the group of children with logoneurosis slow rhythms (5 Hz,) lying within the theta-range of the EEG, were better assimilated. The rhythm is assimilated in the low frequency range among the children with logoneurosis. The relative spectral power of theta-rhythm significantly decreased on the EEG of children with tempo and rhythm speech disorder at low-frequency photostimulation in comparison with the corresponding indicators of the background electroencephalogram; the corresponding indicators in the beta-range, anterior and posterior leads in the alpha-rangeincreased. Based on the obtained data, it has been found, that children with logoneurosis have insufficient response to photostimulation. Such data are associated with insufficient inhibitory effect of the cortex on the subcortical structures. The reduced reactivity and functional insufficiency of the activating system of the brain stem have been noted. Neurophysiological mechanisms of logoneurosis are due to the state of insufficient formation of brain structures, which is confirmed by the results of electroencephalography during rhythmic photostimulation. Changes in the tempo and rhythm of speech during logoneurosis of preschool children provoke stress of the brain mechanisms of regulation, which become apparent by special characteristics of the electrical activity of the brain, both at rest and during load.

How does an athlete’s heart react to studying at university?

2 groups of participants have been studied: I – student-athletes; II – students and postgraduate students, not involved in sport. The functional status of the heart has been studied in three conditions: at rest, during the cognitive test, and under local static load (the wrist dynamometer). The electroencephalography has also been applied. Results demonstrated a statistical decrease in wrist endurance in all participants during the academic year. They proved fatigue development. A pronounced increase of heart rate and arterial blood pressure, as well as the increase of heart rate variability mode and stress index under local load and during the cognitive test, proved the development of the heart functional stress, especially in athletes. Electroencephalography data prove the central origin of adaptation reactions both to mental and to local muscular activity. Disease prevention and health improvement measures are necessary for university students actively involved in sport. One of such measures is relaxation exercises aimed at a decrease in functional stress.