Protoplasmodynamic moments in the clinic of cardiovascular patients

In search of a satisfactory explanation of the pathogenesis of heart failure, the clinic has not been satisfied for a long time with one account of changes in the contractility of the heart muscle and changes in valves, but turns its attention to peripheral circulation.

PHYSICAL ACTIVITY TO IMPROVE THE PHYSIOLOGICAL INDEX OF CARDIOVASCULAR EFFECT

ABSTRACT Introduction: Physical exercise can enhance the body's ability to adapt to the external environment and improve the contractility of the heart. At the same time, it can help improve blood circulation and increase lung capacity. Objective: This article explores the critical role of sports in the prevention of cardiovascular diseases. Methods: This article conducts tests on related physiological indicators such as hemodynamic rheology for students who regularly participate in physical exercise and those who do not participate in physical exercise. Results: Students who exercise regularly and those who do not exercise mobilize faster cardiovascular function at the beginning of work. This shows good adaptability to sports. Conclusion: The use of fitness exercise prescription by students who exercise comprehensively has the most pronounced effect on improving vascular function. Level of evidence II; Therapeutic studies - investigation of treatment results.

Cardiomyocyte Proliferation as a Source of New Myocyte Development in the Adult Heart

Cardiac diseases such as myocardial infarction (MI) can lead to adverse remodeling and impaired contractility of the heart due to widespread cardiomyocyte death in the damaged area. Current therapies focus on improving heart contractility and minimizing fibrosis with modest cardiac regeneration, but MI patients can still progress to heart failure (HF). There is a dire need for clinical therapies that can replace the lost myocardium, specifically by the induction of new myocyte formation from pre-existing cardiomyocytes. Many studies have shown terminally differentiated myocytes can re-enter the cell cycle and divide through manipulations of the cardiomyocyte cell cycle, signaling pathways, endogenous genes, and environmental factors. However, these approaches result in minimal myocyte renewal or cardiomegaly due to hyperactivation of cardiomyocyte proliferation. Finding the optimal treatment that will replenish cardiomyocyte numbers without causing tumorigenesis is a major challenge in the field. Another controversy is the inability to clearly define cardiomyocyte division versus myocyte DNA synthesis due to limited methods. In this review, we discuss several studies that induced cardiomyocyte cell cycle re-entry after cardiac injury, highlight whether cardiomyocytes completed cytokinesis, and address both limitations and methodological advances made to identify new myocyte formation.

The dilatation factor of left atrium in remote period after the mitral valve prosthesis

Objective. Studying of the morphometry indices and contractility of the heart left compartments in the left atrium reduction after prosthesis of a mitral valve. Materials and methods. Into the investigation 634 consequently operated patients with isolated mitral failure were included, who were surgically treated in Amosov National Institute of Cardiovascular Surgery from the 1st of January to the 1st of January 2007 yr. In all the patients the mitral valve prosthesis was performed. In the left atrium dilatation in 49 (7.7%) patients additionally its reduction was done, using paraanular plication of posterior wall of left atrium with the aim to achieve its size lesser than 5,0 cm. Results. Of 49 patients, suffering constant form of atrial fibrillation, thromboembolic complications have occurred in 3 (6.1%) while performance of paraanular plasty of left atrium with simultaneous elimination of its auricle. All thromboembolic complications were nonsevere, and a left atrium size did not exceeded 5.5 sm. Conclusion. The left atrium reduction and elimination of its auricle in the left-sided atriomegaly constitutes a significant element of the result improvement in the mitral valve prosthesis in late period of follow-up.

Hypertrophic cardiomyopathy mutations at the folded-back sequestered β-cardiac myosin S1-S2 and S1-S1 interfaces release sequestered heads and increase myosin enzymatic activity

Hypertrophic cardiomyopathy (HCM) affects 1 in 500 people and leads to hyper-contractility of the heart. Nearly 40 percent of HCM-causing mutations are found in human β-cardiac myosin. Previous studies looking at the effect of HCM mutations on the force, velocity and ATPase activity of the catalytic domain of human β-cardiac myosin have not shown clear trends leading to hypercontractility at the molecular scale. Here we present functional data showing that four separate HCM mutations located at the myosin head-tail (R249Q, H251N) and head-head (D382Y, R719W) interfaces of a folded-back sequestered state referred to as the interacting heads motif lead to a significant increase in the number of heads functionally accessible for interaction with actin. These results provide evidence that HCM mutations can modulate myosin activity by disrupting intramolecular interactions within the proposed sequestered state, thereby leading to hypercontractility at the molecular level.

Sublethal Effects of Solanum nigrum Fruit Extract and Its Pure Glycoalkaloids on the Physiology of Tenebrio molitor (Mealworm)

Background: Solanaceae plants produce glycoalkaloids (GAs) that affect various physiological processes of herbivorous insects and they are being tested as potential alternatives for synthetic pesticides. They cause lethal and sublethal effects. Nevertheless, their mode of action remains unclear. Therefore, we examined the effects of Solanum nigrum fruit extracts and pure glycoalkaloids on a model beetle, Tenebrio molitor. Methods: Plant extracts or pure alkaloids were added to the food of the larvae for three days. The lipid, glycogen, and protein content in the fat body and the midgut were determined, and the contractility of the heart, hindgut, and oviduct muscles was tested using the video-microscopy technique. Finally, the ultrastructure of the fat body and the midgut was observed using electron microscopy. Results: No lethal effects were noted. Sublethal changes were observed in the content of biomolecules, malformations of organelles, chromatin condensation, and heart and oviduct contractility. The observed effects differed between the tested glycoalkaloids and the extract. Conclusions: Both the extract and pure GAs have a wide range of effects that may result in impaired development, food intake, and reproduction. Some early effects may be used as bioindicators of stress. The effects of the extract and pure alkaloids suggest that the substances produced by the plant may act additively or synergistically.

Frank-Starling Mechanism and Short-Term Adjustment of Cardiac Flow

The Frank-Starling Law of the heart is a filling-force mechanism, a positive relationship between the distension of a ventricular chamber and its force of ejection. The functioning of the cardiovascular system is usually described by means of two intersecting curves: the cardiac and vascular functions, the former related to the contractility of the heart and the latter related to the after-load imposed to the ventricle. The crossing of these functions is the so-called operation point, and the filling-force mechanism is supposed to play a stabilizing role for the short-term variations in the working of the system. In the present study, we analyze whether the filling-force mechanism is responsible for such a stability within two different settings: one-ventricle, as in fishes, and two-ventricle hearts, as in birds and mammals. Each setting was analyzed under two scenarios: presence of the filling-force mechanism and its absence. To approach the query, we linearized the region around an arbitrary operation point and put forward a dynamical system of differential equations to describe the relationship among volumes of ventricular chambers and volumes of vascular beds in face of blood flows governed by pressure differences between adjacent compartments. Our results show that the filling-force mechanism is not necessary to give stability to an operation point. The results indicate that the role of the filling-force mechanism is related to decrease the controlling effort over the circulatory system, to smooth out perturbations and to guarantee faster transitions among operation points.Summary StatementWe address the role of the Frank-Starling mechanism and show that it has no role in the stability of the circulatory system. Rather, it accounts for decreasing the controlling effort and speeding up changes in cardiac output.

Direct interaction between troponin and myosin enhances the ATPase activity of heavy meromyosin

Contractility of the heart muscle is a result of sliding movements between thick and thin filaments, produced by interactions between actin and myosin during the cross-bridge cycle. Activation of the myofilament is triggered by Ca

Nuclear Cardiac Imaging

Nuclear cardiac imaging refers to cardiac radiological diagnostic techniques performed with the aid of radiopharmaceuticals, which are perfused into the myocardium as markers. These imaging studies provide a wide range of information about the heart, including the contractility of the heart, the amount of blood supply to the heart and whether parts of the heart muscle are alive or dead. This is essential information for cardiologists, and nuclear imaging has become an increasingly important part of the cardiologist's armamentarium. Chapters in Nuclear Cardiac Imaging cover historical, technical and physiological considerations, diagnosis and prognosis, conditions other than Coronary Artery Disease (CAD), advanced cardiac imaging, and challenges and opportunities. New to the fifth edition are key point summaries at the start of each chapter, clinical cases with videos, and a question and answer chapter on practical issues. This title is ideal for nuclear cardiologists in training and nuclear clinicians alike who are searching for quick answers to important clinical and technical questions.