INFLUENCE OF DIABETES MELLITUS ON THE ACTIVITY OF METABOLIC ENZYMES AND SERCA2A EXPRESSION IN CARDIOMIOCYTES AND ITS RELATION WITH INOTROPIC REACTIONS OF THE MYOCARDIUM OF PATIENTS WITH CORONARY HEART DISEASE

The work was performed on the biopsy material of the heart with chronic coronary heart disease (CHD), and patients with CHD combined with type 2 diabetes mellitus. It was shown that the activity of succinate dehydrogenase (LDH) enzymes in the myocardium of patients with CHD was higher than in patients with combined pathology. Both groups had patients with both “high” and “low” SERCA2a protein. In addition, the inotropic myocardial response of patients in each group also divided into 2 subgroups. At the same time, the “high content” of the SERCA2a protein corresponded to the positive dynamics of the force-interval relationship, and the “low content” of the protein studied corresponded to the negative dynamics of the force-interval relationship (mechanical restitution). At the combined development of CHD and diabetes mellitus with a short duration of the disease, the positive dynamics of the force-interval relationship is more pronounced and corresponds to a higher level of SERCA2a expression than in the development of CHD only.

THE EQUIVALENCE BETWEEN FEEDBACK AND DISSIPATION IN IMPACT OSCILLATORS

We analyze an important class of engineering systems characterized by the discontinuous motion of a spring-mass constrained by the motion of a feedback-assisted actuator. We show that the combined effects of mechanical restitution coefficient and displacement feedback can be exactly represented by a single equivalent dissipation coefficient. We also show that the topological properties of the surfaces of section of orbits generated by impact oscillators which possess differing proportions of restitution and feedback levels, but whose equivalent dissipation coefficients are equal, are equivalent and universally scalable. The scaling law allows us to interchange the effects of restitution and feedback coefficients and so, effectively, eliminate one of these parameters from the equations of motion. Thus, the topological properties of dissipative feedback-assisted systems can be seen as scaled versions of either purely dissipative, or purely feedback-assisted, oscillators.