Pathogenic features of cell death in myocardial alterations of different genesis

In the present work the features of initiation of cardiomyocyte regulated cell death at the early stages of cardiac alteration of different etiology were studied. The experiments were performed on male rabbits in which we modeled acute ischemia of the left ventricle, hemodynamic overload of the left ventricle and a diffuse toxic damage of the myocardium. Мechanisms of cardiomyocyte autophagy and apoptosis were evaluated by means of morphological and immunohistochemical investigation of the myocardium. Cardiomyocyte autophagy was studied by estimation of protein BECN1 expression, apoptotic process in cardiomyocytes – by estimation of proapoptotic protein BAX and antiapoptotic protein BCL-2. It was found that mechanisms mediating realization of some types of cardiomyocyte regulated death may have different properties depending on the character of myocardial damage. It was shown that under acute myocardial ischemia the activity of BECN1-induced cardiomyocyte autophagy is increased and on the 1-st day there is also activation of mitochondrial pathway of cardiomyocyte apoptotic death. Acute toxic damage and acute overload of the left ventricle are accompanied by inhibition of cardiomyocyte autophagy.

Functional characteristic of chronostructure of the cardio-vascular system in the dynamics of genetic hypertension

In the present work some indices characterizing functional state of the cardio-vascular system under long-term hypertension were studied. As a target of research we used spontaneously hypertensive rats (SHR) and normotensive Wistar rats (control) in which we implanted (surgically) radio-transmitters monitoring BP, ECG and motion activity for several months continuously. The obtained data were processed with computer programs: Dataquest A.R.T.4.2 Gold (USA) и ChronosFit (Germany). It was found that maximal daily systolic BP significantly increased at the stable stage of hypertension; inhibition of the chronotropic function of the myocardium at the late terms of the experiment was also typical. It was shown that rhythmic characteristics of the investigated indices were gradually suppressed as hypertension was developing which was also accompanied by disorganization of their circadian profiles.

Of the dissertation «Electrophysiological and Сhronobiological characteristics of myocardial damage (in outpatient practice in Lebanon and the Russian Federation)»

The purpose of research is to evaluate the diagnostic capabilities of measuring ECG signal microalternations as a new component among the set of diagnostic tests that assess abnormalities in the electrophysiological properties of the myocardium. The work is based on the survey data and observation of 362 subjects who conducted a total of 488 surveys across the five series of studies.This defined the reference parameters for the common range of fluctuations of ECG signal microalternations in the healthy and sick population of Lebanon. During the screening, the DK-ECG method showed a high diagnostic value in detecting myocardial damage. Particularly, and based on a value of the index "Myocardium" of 15% , the "normal" and "pathological" classification showed a sensitivity of 82.5% and a specificity of 58.1% for the analysis dataset. The work then focused on the borderline values for assessing the electrophysiological status of the myocardium according to DM for both the daily and the annual monitoring in the Lebanese population. It was established that the indicators of T-wave microalternations taken at three points (T1, T2 and T3) during the year in the young subjects group (age 20-40 45 years) are lower than the same indicators in the older subjects group (41-60 years). Moreover, the average difference value in the amplitudes of T2-T1 in the older group is 0.5-1.0 mV higher than that in the young group. The research also identified a number of previously unknown annual rhythm characteristics of the cardiovascular system that could potentially have important theoretical as well as clinical implications. The work demonstrated the presence of seasonal changes in DM indicators and the effect of various test actions on the parameters of the ECG signal microalternations in a group of healthy individuals. Furthermore, by analyzing the dispersion parameters of low amplitude ECG signal vibration during the depolarization/repolarization phases, it was noted that a set of deviations and predefined changes in these parameters can be observed in patients with cardiovascular disease. The work highlight the utility of capitalizing on daily and annual monitoring in clinical practice to expand the diagnostic capabilities of the DM method. The obtained data emphasize the feasibility of using DM-Holter indicators in the field of medicine (chronobiology) as a new tool in evaluating the myocardium electrophysiological state. It is finally argued that the study of biorhythms carries a considerable promise for various fields of medicine including diagnosis, ambulance organization, occupational health, profession screening, evaluation of adaptive human capabilities, as well as correction of therapy of patients with regard to their biorhythms.