Analysis of heart rate variability and arterial blood pressure in different functional tests in men and women

Experiments with simultaneous recording of the heart rate, peripheral blood pressure, and respiration showed differences between the cardiovascular system parameters of men and women at rest and during various functional tests (cold, mental and physical exercise, spirometric mask testing). The results of several series of experiments using the same sample showed that women were characterized by a relationship between the state of the cardiovascular system and the psychoemotional status and well-being, as well as by a greater involvement of the central mechanisms in the regulation of the cardiovascular system when functional tests are performed. A high level of tonic activity and high reactivity of the sympathetic link of regulation of the cardiovascular system is typical of men.     

Changes in parameters of tachography and heart rate variability in students differing in the level of psychoemotional stress and type of temperament during an academic test week

Female students were examined to evaluate the effect of a test week on the parameters of tachography and heart rate variability depending on their initial psychoemotional stress level and type of temperament. A test week was shown to be a rather weak stressor, which virtually did not affect the psychological status of the students. However, their autonomic status clearly changed during the test week. This was caused by activation of the sympathetic autonomic system and was observed in both the students with a favorable psychoemotional state and choleric and sanguine subjects.     

Correction of the functional state of aircraft-carrier aviation pilots by a course of inhalation of therapeutic doses of xenon during a long sea campaign

The article considers the efficacy of the courses of xenon-oxygen inhalation for the correction of the functional state of aircraft-carrier aviation pilots in a distant sea campaign. The course of inhalation procedures was shown to stabilize the vagosympathetic balance of the body, to restore the level of the functional state of the cardiovascular system, and to retain its functional reserve at an adequate level, thus considerably improving the subjective psychoemotional state of the pilots, which manifests itself in the improvement of self-esteem, an increase in activity, well-being, and mood, as well as in an adequate decrease in the level of reactive anxiety. The results obtained give evidence of the benefits of the use of special xenon-based gas mixtures for correcting the pilots’ functional state in the most stressful periods of their professional activity. Recommendations on the application of this method by military medicine have been given.     

Influence of examination stress and psychoemotional characteristics on the blood pressure and heart rate regulation in female students

During the semester and immediately before an examination, changes in the heart rate variability, blood pressure, and state anxiety induced by examination stress, as well as the dependence of these changes on the probabilistic prediction and actual examination mark, were investigated. Before an examination, most students exhibited an increase in state anxiety, diastolic blood pressure, and heart rate; the last of these is connected with an increase in the LF/HF ratio. The behavior of the cardiovascular system of the students (who were females) under psychoemotional stress varied considerably depending on how well they were prepared for the examination and on the subjective prediction of success. The importance of the type of heart rate regulation during the semester for the progress of examination stress was established.     

Subtype-specific clinically important effects of alpha 2-adrenergic receptors

A- B- and C-subtypes of alpha 2-adrenoreceptors present in all mammals are involved in responses to currently existing subtype-nonselective ligands of these receptors widely used in medicine. Each of the subtypes has its own specific distribution in tissue and cells, onthogenetic pattern, specific regulation of activity and expression, and, as result, specific physiological functions. The latter suggests opportunities of using the subtype-specific for correction of the functions depending on this receptor. The article reviews the role of individual subtypes of alpha 2-adrenoreceptors in regulation of neurochemical transmission of cardiovascular system, psychoemotional state and development of psychic disorders, and also male sexual behaviour.     

Features of the Response of the Cardiovascular System to Geomagnetic Disturbances at Different Latitudes

The principles of multi-latitude monitoring of Heliomed-2 for obtaining new data on the impact of space weather on human health are described. The results of synchronous monitoring of responses of the cardiovascular system and psychoemotional state of healthy volunteers to changes in geomagnetic disturbances at high (Tiksi village and Yakutsk) and middle (Saratov) latitudes are presented. In all the examined groups, the effect of synchronization of the processes of repolarization of the ventricular myocardium (according to the coefficient of symmetry of the T wave of the electrocardiogram) and geomagnetic disturbances, as well as synchronization of reactive anxiety and geomagnetic disturbances was revealed. It was found that the group cardiac sensitivity and psychological sensitivity to geomagnetic disturbances coincide regardless of the latitude of residence in the same group of volunteers.

     

Characteristics of amaranth oil effect on the antioxidant system of the liver and blood in mice with malignant lymphoma growth

The dynamics of functioning of the lipid peroxidation <--> antioxidant activity system was studied during the tumor growth in the blood, liver and NK/Ly cells in mice fed with amaranth oil (100 microL/100 g, once a day, 10 days before inoculation and during tumor growth for 14 days). Different effects on antioxidant activity were demonstrated. Activity of the antioxidant enzymes in hepatocytes of mice fed with amaranth oil was aimed at maintenance of antioxidant defence in tumor growth. This effect was achieved owing to the marked increase in superoxide dismutase, preserved catalase and decreased glutathione peroxidase activities with simultaneous increase in hydroperoxides levels and decrease of thiobarbituric acid-reactive subspecies. Changes observed in NK/Ly lymphoma cells were directed to providing a higher prooxidant activity than in the liver cells. Modification of antioxidant activity induced by amaranth oil can maintain oxygen homeostasis, morphofunctional state and inhibit tumor cells proliferation.     

Autonomic control of blood pressure in mice: basic physiology and effects of genetic modification

Control of blood pressure and of blood flow is essential for maintenance of homeostasis. The hemodynamic state is adjusted by intrinsic, neural, and hormonal mechanisms to optimize adaptation to internal and environmental challenges. In the last decade, many studies showed that modification of the mouse genome may alter the capacity of cardiovascular control systems to respond to homeostatic challenges or even bring about a permanent pathophysiological state. This review discusses the progress that has been made in understanding of autonomic cardiovascular control mechanisms from studies in genetically modified mice. First, from a physiological perspective, we describe how basic hemodynamic function can be measured in conscious conditions in mice. Second, we focus on the integrative role of autonomic nerves in control of blood pressure in the mouse, and finally, we depict the opportunities and insights provided by genetic modification in this area.     

Metabolic system of acid-base homeostasis in the human and animal body

Peculiarities of carbohydrate, lipid, amino acid nucleotide metabolism, of the tricarboxylic acid cycle functioning and of the oxidative phosphorylation have been studied in man and animals under conditions of changes in the acid-base equilibrium (ABE) state in the organism. The results of studies are analyzed and generalized. Strictly defined peculiarities of changes in the mentioned aspects of metabolism depending on the ABE state in the organism are revealed. Basing on a new interpretation of the experimental data and detected regularities in the metabolism, the author has drawn a conclusion on the existence of the previously unknown system of acid-base homeostasis in tissues. The physiological sense of this system functioning is the regulation of the intracellular acid-base equilibrium stability. The regulation mechanisms promoting functioning of this system are discussed. The system is shown to be of great applied significance for improvement of methods to cure a number of human and animal diseases as well as for an increase of the productivity of animals.     

A genome-wide screen in yeast identifies specific oxidative stress genes required for the maintenance of sub-cellular redox homeostasis

Maintenance of an optimal redox environment is critical for appropriate functioning of cellular processes and cell survival. Despite the importance of maintaining redox homeostasis, it is not clear how the optimal redox potential is sensed and set, and the processes that impact redox on a cellular/organellar level are poorly understood. The genetic bases of cellular redox homeostasis were investigated using a green fluorescent protein (GFP) based redox probe, roGFP2 and a pH sensitive GFP-based probe, pHluorin. The use of roGFP2, in conjunction with pHluorin, enabled determination of pH-adjusted sub-cellular redox potential in a non-invasive and real-time manner. A genome-wide screen using both the non-essential and essential gene collections was carried out in Saccharomyces cerevisiae using cytosolic-roGFP2 to identify factors essential for maintenance of cytosolic redox state under steady-state conditions. 102 genes of diverse function were identified that are required for maintenance of cytosolic redox state. Mutations in these genes led to shifts in the half-cell glutathione redox potential by 75-10 mV. Interestingly, some specific oxidative stress-response processes were identified as over-represented in the data set. Further investigation of the role of oxidative stress-responsive systems in sub-cellular redox homeostasis was conducted using roGFP2 constructs targeted to the mitochondrial matrix and peroxisome and E(GSH) was measured in cells in exponential and stationary phase. Analyses allowed for the identification of key redox systems on a sub-cellular level and the identification of novel genes involved in the regulation of cellular redox homeostasis.     

Central cholinergic signal-mediated neuroendocrine regulation of vasopressin and oxytocin in ovine fetuses

Background  

The hypothalamic-neurohypophysial system plays a fundamental role in the maintenance of body fluid homeostasis by secreting arginine vasopressin (AVP) and oxytocin (OT) in response to a variety of signals, including osmotic and nonosmotic stimuli. It is well established that central cholinergic mechanisms are critical in the regulation of cardiovascular responses and maintenance of body fluid homeostasis in adults. Our recent study demonstrated that intracerebroventricular (i.c.v.) injection of carbachol elicited an increase of blood pressure in the near-term ovine fetuses. However, in utero development of brain cholinergic mechanisms in the regulation of the hypothalamic neuropeptides is largely unknown. This study investigated AVP and OT neural activation in the fetal hypothalamus induced by central carbachol.     

The role of multi-enzyme complexes in the integration of cell metabolism

General properties of enzymes and structurally ordered multienzyme complexes as controllable systems are discussed: the spatial isolation of working sites and sites of control and the realization of control mechanisms with the participation of "external" factors which provide the optimal functioning of the controllable system in the biological system of higher level of complexity. The basic mechanisms of the control of soluble enzymes are isosteric and allosteric mechanisms which directed to the maintenance of cellular homeostasis. The mechanism of functioning of a multienzyme complex as a whole which is realized with the participation of second messengers is classified as a mechanism for tracing of the signals from higher levels of the control of metabolism (from nervous, hormonal and immune systems). When discussing the control of functioning of the multienzyme complexes, special attention was paid to the complex of glycolytic enzymes formed on the structural proteins of skeletal muscles and on the membranes. An order of assembly of the complex of glycolytic enzymes is proposed. The possible localization of this complex in myofibrils is discussed.     

The role of glucose homeostasis on immune function in response to exercise: The impact of low or higher energetic conditions

Immune cells are bioenergetically expensive during activation, which requires tightly regulated control of metabolic pathways. Both low and high glycemic conditions can modulate immune function. States of undernourishment depress the immune system, and in the same way, excessive intake of nutrients, such as an obesity state, compromise its functioning. Multicellular organisms depend on two mechanisms to survive: the regulation and ability to store energy to prevent starvation and the ability to fight against infection. Synergic interactions between metabolism and immunity affect many systems underpinning human health. In a chronic way, the breakdown of glycemic homeostasis in the body can influence cells of the immune system and consequently contribute to the onset of diseases such as type II diabetes, obesity, Alzheimer's, and fat and lean mass loss. On the contrary, exercise, recognized as a primary strategy to control hyperglycemic disorders, also induces a coordinated immune-neuro-endocrine response that acutely modulates cardiovascular, respiratory, and muscle functions and the immune response to exercise is widely dependent on the intensity and volume that may affect an immunodepressive state. These altered immune responses induced by exercise are modulated through the “stress hormones” adrenaline and cortisol, which are a threat to leukocyte metabolism. In this context, carbohydrates appear to have a positive acute response as a strategy to prevent depression of the immune system by maintaining plasma glucose concentrations to meet the energy demand from all systems involved during strenuous exercises. Therefore, herein, we discuss the mechanisms through which exercise may promotes changes on glycemic homeostasis in the metabolism and how it affects immune cell functions under higher or lower glucose conditions.     

Emotional Stress in Students during Examinations

The psychoemotional reactions of students caused by examinations were studied on the basis of a modern theory of emotions by means of a complex of modern psychophysiological methods. To study the role of probabilistic forecasting of results in the development of the psychoemotional state, each student was asked to predict his or her mark. Groups were formed based on the difference between the expectations and the actual mark. In general, examination-induced emotional stress in students was characterized by a complex of psychophysiological and autonomic changes depending on the probabilistic estimation of the mark, preparedness for the examination, and the result. The theoretic aspect of the study was related to the development of the concept of emotion genesis. The practical aspect included educational process optimization in order to improve the psychoemotional status of students.     

Regulation of cholesterol metabolism in the ethionine-induced premalignant rat liver

The early premalignant liver provides a model in which to study metabolic alterations that may be permissive for the development of full malignancy. Although there are biochemical changes in this model, there are no detectable morphological ones when compared with a normal, fully differentiated liver. The maintenance of cholesterol homeostasis, essential for proper functioning of mammalian cells, is known to be altered in malignancy. We used the ethionine-induced premalignant liver model to study the effects of the premalignant state on cellular parameters involved in the maintenance of hepatic cholesterol homeostasis. Cholesterol synthesis was elevated about twofold in the livers of rats treated with ethionine as was the activity of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, its rate limiting enzyme. There was no change in reductase activation state. Acyl coenzyme A:cholesterol acyl-transferase (ACAT) was decreased about 30%, and cholesterol 7 alpha-hydroxylase, about 50%. There was no significant change in neutral cholesteryl ester hydrolase activity, but acid hydrolase activity was decreased. There was little change in low density lipoprotein receptor protein as determined by immunoblotting. Biliary lipid secretion was in the normal range when expressed per gram liver; however, bile flow was doubled. The ethionine-fed animals were mildly hypocholesterolemic and had an altered serum lipoprotein pattern. Cholesterol synthesis and HMG-CoA reductase activity exhibited decreased sensitivities to inhibition by dietary cholesterol when compared to control livers. However, sensitivity to intragastrically administered mevalonolactone was not altered. Although ACAT activity was increased by mevalonolactone administration to levels similar to those in untreated animals, it was not increased in the ethionine-fed animals by feeding cholesterol. The ethionine-induced premalignant liver responded to ethinyl estradiol treatment in a manner similar to that of the control, i.e., profound hypolipidemia, increased low density lipoprotein receptors, decreased reductase activity, and increased cholesterol esterification. Thus, these livers retained their estrogen responsiveness. Taken together, the data demonstrate that the major elements involved in maintaining hepatic cholesterol homeostasis are present in the premalignant liver, although in some cases at levels that are different from the control. However, the susceptibility to regulation was altered in these livers to suggest markedly decreased availability of cholesterol of exogenous origin to the regulatory compartment(s). Further, coupling of the different elements involved in maintenance of hepatic cholesterol homeostasis appeared to have been changed.     

Phase Synchronization of Hemodynamic Variables at Rest and after Deep Breathing Measured during the Course of Pregnancy

Background

The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations.

Methodology

Continuous monitoring of heart rate (R-R interval; derived from the 3-lead electrocardiography), blood pressure, and thoracic impedance was carried out in thirty-six women at six time-points throughout pregnancy. In order to quantify in addition to the longitudinal effects on baseline levels throughout gestation the immediate adaptive heart rate and blood pressure changes at each time point, a simple reflex test, deep breathing, was applied. Consequently, heart rate variability and blood pressure variability in the low (LF) and high (HF) frequency range, respiration and baroreceptor sensitivity were analyzed in resting conditions and after deep breathing. The adjustment of the rhythms of the R-R interval, blood pressure and respiration partitioned for the sympathetic and the parasympathetic branch of the autonomic nervous system were quantified by the phase synchronization index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators.

Results

Heart rate and LF/HF ratio increased throughout pregnancy and these effects were accompanied by a continuous loss of baroreceptor sensitivity. The increases in heart rate and LF/HF ratio levels were associated with an increasing decline in the ability to flexibly respond to additional demands (i.e., diminished adaptive responses to deep breathing). The phase synchronization index γ showed that the observed effects could be explained by a decreased coupling of respiration and the cardiovascular system (HF components of heart rate and blood pressure).

Conclusions/Significance

The findings suggest that during the course of pregnancy the individual systems become increasingly independent to meet the increasing demands placed on the maternal cardiovascular and respiratory system.     

Role of thyroid hormones-induced oxidative stress on cardiovascular physiology

Thyroid hormones (THs) play an essential role in the maintenance of cardiovascular homeostasis and are involved in the modulation of cardiac contractility, heart rate, diastolic function, systemic vascular resistance, and vasodilation. THs have actions on cardiovascular physiology through the activation or repression of target genes or the activation of intracellular signals through non-genomic mechanisms. Hyperthyroidism alters certain intracellular pathways involved in the preservation of the structure and functionality of the heart, causing relevant cardiovascular disorders. Reactive oxygen species (ROS) play an important role in the cardiovascular system, but the exacerbated increase in ROS caused by chronic hyperthyroidism together with regulation on the antioxidant system have been associated with the development of cardiovascular dysfunction. In this review, we analyze the role of THs-induced oxidative stress in the cellular and molecular changes that lead to cardiac dysfunction, as well as the effectiveness of antioxidant treatments in attenuating cardiac abnormalities developed during hyperthyroidism.     

Use of principles of prenosological diagnosis for assessing the functional state of the body under stress conditions as exemplified by bus drivers

The functional state of the body was assessed in healthy subjects performing their daily work under stress conditions. The study sample comprised bus drivers aged 25–65 years. A prenosological approach was used to assess the borderline between the physiologically normal state and pathological conditions. At the first stage of the study (prenosological screening), the subjects were divided into four groups with different adaptive capacities of the body. At the second stage of the study, a detailed prenosological examination was performed to determine the causes and mechanisms of evolution of prenosological conditions into premorbid conditions and further into adaptation failure, resulting in diseases. It was found that the bus drivers experienced chronic occupational stress leading to the overtension and exhaustion of regulatory mechanisms and to the rapid development of cardiovascular pathology. Long-term mental and psychoemotional tension in drivers associated with occupational stress leads to the activation of suprasegmental structures involved in the control of physiological functions; to a decrease in the functional reserves; and, consequently, to the worsening of the psychophysiological and cardiorespiratory function of the body. As a result of the study, a group of bus drivers with an increased risk of diseases, including cardiovascular, was determined and recommendations on workforce health protection were developed for the managers of the motor transport enterprise.