Functional state of the cardiovascular system in 13-year-old adolescents with different types of autonomic nervous regulation

The features of the functional state of cardiovascular system in 13-year-old children with different types of autonomic nervous regulation were studied. Children with normotonic and parasympathetic types of autonomic regulation were found to have the highest adaptation capacities. The autonomic nervous system influences the bioelectrical processes in myocardium, the duration of cardiac cycle phases, and cerebral blood flow. Schoolchildren aged 13 years with higher sympathetic activity have shorter duration of the cardiac cycle, the phase of isometric contraction, and diastole. They have a lower pulse blood flow rate and a higher tone of large and medium cerebral vessels. No relationship was revealed between the initial autonomic nervous regulation of heart rate and the type of adaptation of myocardium to physical dynamic loads, as well as the type of adaptation of cerebral circulation to mental stress.     

Adult patients with congenital adrenal hyperplasia have elevated blood pressure but otherwise a normal cardiovascular risk profile

Objective

Treatment with glucocorticoids and mineralocorticoids has changed congenital adrenal hyperplasia (CAH) from a fatal to a chronic lifelong disease. Long-term treatment, in particular the chronic (over-)treatment with glucocorticoids, may have an adverse effect on the cardiovascular risk profile in adult CAH patients. The objective of this study was to evaluate the cardiovascular risk profile of adult CAH patients.

Design

Case-control study.

Patients and Measurements

In this case-control study the cardiovascular risk profile of 27 adult CAH patients and 27 controls, matched for age, sex and body mass index was evaluated by measuring ambulatory 24-hour blood pressure, insulin sensitivity (HOMA-IR), lipid profiles, albuminuria and circulating cardiovascular risk markers (PAI-1, tPA, uPA, tPA/PAI-1 complex, hsCRP, adiponectin, IL-6, IL-18 and leptin).

Results

24-Hour systolic (126.3 mmHg±15.5 vs 124.8 mmHg±15.1 in controls, P = 0.019) and diastolic (76.4 mmHg±12.7 vs 73.5 mmHg±12.4 in controls, P<0.001) blood pressure was significantly elevated in CAH patients compared to the control population. CAH patients had higher HDL cholesterol levels (P<0.01), lower hsCRP levels (P = 0.03) and there was a trend toward elevated adiponectin levels compared to controls. Other cardiovascular risk factors were similar in both groups.

Conclusion

Adult CAH patients have higher ambulatory blood pressure compared to healthy matched controls. Other cardiovascular risk markers did not differ, while HDL-cholesterol, hsCRP and adiponectin levels tended to be more favorable.     

An alternative sauropod physiology and cardiovascular system that eliminates high blood pressures

Siegwarth, J.D., Smith, C.N. & Redman, P.D. 2010: An alternative sauropod physiology and cardiovascular system that eliminates high blood pressures. Lethaia, Vol. 44, pp. 46–57. The long neck of an adult sauropod has been found structurally unsuitable for high browsing while standing on all four feet. Some juveniles might have used a tripodal stance, but an analysis of the motion of the centre of mass shows a large adult sauropod could not. We propose here that sauropods could have browsed high by sitting, squatting or even kneeling on their hind legs to elevate their heads without a sharp bend at the base of the neck. A large sauropod needs a way to deal with very high blood pressure when high browsing. Arterial pumping is suggested here as a means of avoiding the need for high blood pressure. □Blood pressure, browsing posture, cardiovascular system, form vis‐à‐vis function, neck length, physiology, sauropods, tripodal stance.     

Functional characteristics of normal and pathologic erythrocytes

Polarographic titration in a closed cell of blood samples and concentrated Hb solutions was used to study the regulation of the release of oxygen by the red cell. The effect of temperature, polyethylenglycol and metabolites normally found in the erythrocyte was determined by spectrophotometric and polarographic methods. Some pecularities of O2-transport and release in beta-thalassemia, functional hypoxia and Cooley-disease are described.     

正常大鼠植入高血压大鼠肾脏后动脉血压的变化

本实验对12周龄的自发性高血压大鼠(spontaneouslyhypertensiverat,SHR)及其对照组WistarKyoto(WKY)大鼠进行了肾脏移植的研究,并观察受肾移植大鼠动脉血压的变化以及免疫抑制剂对动脉血压的影响。用尾套法对接受同窝另一同胞WKY大鼠肾脏移植且存活5周的6只WKY大鼠(A组)及接受SHR肾脏移植且存活5周的6只WKY大鼠(B组)的尾动脉收缩压进行检测,移植前A、B两组受肾移植大鼠的尾动脉收缩压分别为180±093和183±068kPa,无统计学显著差异(P>005);移植后3、4、5周时,B组大鼠的尾动脉收缩压显著高于A组大鼠,移植后5周时,A,B两组大鼠的收缩压分别为190±071和230±069kPa(P<0001);所用剂量的免疫抑制剂CsA对双侧肾脏完整以及右侧肾脏切除的SHR、WKY大鼠的动脉血压无显著影响。以上结果表明,SHR的肾脏在高血压的形成中可能起重要作用     

Morphofunctional characteristics of young rowers with increased blood pressure

The morphofunctional characteristics of 47 young athletes (rowers) were studied. Stage I essential hypertension was found in 25.6% of the young athletes and high normal blood pressure (BP) in 8.5% of the athletes. Detailed clinical and functional observation has shown that, in the group of rowers with an elevated BP, the weight of the left ventricle myocardium was increased and the functional reserve was reduced as compared to the group of athletes with a normal BP level.     

Functional characteristics of hemodynamics in adolescents under the conditions of different motor activities

The formation of functional systems in correspondence with the conditions of natural activity is the most important issue of developmental physiology. In this study, data on the assessment of the state of central and cerebral hemodynamics, as well as indices of spectral analysis of the heart rate’s variability (HRV) in adolescents depending on the level of motor activity has been collected and systematized. The possibility of integration of methods of rheoencephallography and cardiorythmography for the assessment of the characteristics of the ontogenetic formation of the cardiovascular system has been studied. Analysis of the formation of indices of hemodynamics during an academic year and the training cycle in swimmers and healthy adolescents who do not enroll in sports classes has been made. Changes in, and correlations between, the parameters of central hemodynamics and cerebral circulation, as well as parameters of HRV, have been detected. Analysis of the changes in the statistical indices of the cardiac rhythm in adolescents during an academic year on the basis of the qualitative and quantitative characteristics of the state of regulatory systems, as well as the determination of the direction of the response to the combination of academic loads and the factor of physical training, permitted a detailed study of changes that take place in some hemodynamic parameters in athletes and students, which is of particular importance for the diagnosis of their functional state.     

A model of human cardiovascular system containing a loop for the autonomic control of mean blood pressure

We propose a model for the human cardiovascular system that describes the cardiac cycle, the autonomic regulation of heart and vessels, the baroreflex, and the formation of blood pressure. The model also allows for the influence of respiration on these processes. It has been found that an allowance for nonlinearity and insertion of a loop for the autonomic control of mean blood pressure (having the form of selfoscillating time-delay system) enables obtaining model signals with statistical and spectral characteristics that are qualitatively and quantitatively similar to those for experimental signals. The model reproduces the phenomenon of synchronization of the loop for mean blood pressure regulation with a basic frequency of approximately 10 s by the signal of respiration.     

Effect of prolactin on blood pressure and cardiovascular responsiveness in the rat

The effects of chronic ovine PRL (oPRL) infusion on resting systolic blood pressure (BP), heart rate, and pressor responsiveness to acute administration of norepinephrine and angiotensin were studied in adult male Sprague-Dawley rats. oPRL was administered over 7 days, via osmotic pump implanted ip on Day 1, at rates of 0, 0.15, 0.30, 0.60, 1.20, and 4.80 micrograms/hr. Resting BP and heart rate were indirectly determined in conscious rats by tail cuff technique on Days 1, 4, and 7 following pump implantation. In addition, acute pressor responses to ia norepinephrine (4.3 micrograms) and angiotensin (1.25 micrograms) were directly measured via arterial cannula in halothane-anesthetized rats on Day 7 of oPRL administration. oPRL infusion did not alter resting BP or heart rate over the 7 days. However, oPRL increased the BP response to norepinephrine at infusion rates of 0.60 and 4.80 micrograms/hr (P less than 0.01 vs controls). Body weight increases during the study were also greater in groups receiving 0.15, 0.30, 0.60, and 4.80 micrograms oPRL/hr (P less than 0.05) than those in control animals. oPRL decreased pressor responses to angiotensin at infusion rates of 0.30 and 1.20 micrograms/hr (P less than 0.01). These data suggest that, although the vascular effects of oPRL may not be evident under resting conditions, oPRL enhances vascular reactivity to norepinephrine infusion and depresses vascular reactivity to angiotensin infusion. Furthermore, at oPRL infusion rates which affect pressor responses to norepinephrine, oPRL increases body weight gain. These findings support a role for PRL in cardiovascular regulation during conditions of altered sympathetic activity.     

CXCL5 polymorphisms are associated with variable blood pressure in cardiovascular disease-free adults

Age-related macular degeneration (AMD) is a complex and multifaceted disease involving contributions from both genetic and environmental influences. Previous work exploring the genetic contributions of AMD has implicated numerous genomic regions and a variety of candidate genes as modulators of AMD susceptibility. Nevertheless, much of this work has revolved around single-nucleotide polymorphisms (SNPs), and it is apparent that a significant portion of the heritability of AMD cannot be explained through these mechanisms. In this review, we consider the role of common variants, rare variants, copy number variations, epigenetics, microRNAs, and mitochondrial genetics in AMD. Copy number variations in regulators of complement activation genes (CFHR1 and CFHR3) and glutathione S transferase genes (GSTM1 and GSTT1) have been associated with AMD, and several additional loci have been identified as regions of potential interest but require further evaluation. MicroRNA dysregulation has been linked to the retinal pigment epithelium degeneration in geographic atrophy, ocular neovascularization, and oxidative stress, all of which are hallmarks in the pathogenesis of AMD. Certain mitochondrial DNA haplogroups and SNPs in mitochondrially encoded NADH dehydrogenase genes have also been associated with AMD. The role of these additional mechanisms remains only partly understood, but the importance of their further investigation is clear to elucidate more completely the genetic basis of AMD.     

Performance characteristics of conditioned blood pressure elevations in the baboon

Operant conditioning of diastolic blood pressure elevation was accomplished in six baboons (Papio sp.) by a procedure using food delivery when diastolic pressure was maintained above a prespecified level, and shock delivery when diastolic pressure remained below that level. Data from steady-state performance indicated a rise in diastolic pressure by a median 22 mm Hg when the daily session was begun. Elevated levels of diastolic blood pressure and low shock frequencies were maintained throughout the 12-hour session. The frequency and duration of shifts in diastolic pressure to below criterion level were found to be variable during the first 1–2 hours but were stable throughout the remainder of the session. Heart rate had a phasic temporal pattern over the 12-hour session, characterized for most subjects by a rate increase at session onset followed by a rate decrease. Analysis of individual performance records showed that the blood pressure increases could occur without concomitant elevations in heart rate.This research was supported by grant No. 2R01HL17958-05 from the National Heart, Lung, and Blood Institute. The authors wish to thank J. V. Brady and I. Iversen for helpful editorial suggestions.     

Functional development of the vegetative regulation of the cardiovascular system in human ontogenesis

Using the functional tests method, it was shown that the ontogenetic course of development of the cardiovascular system vegetative regulation after the age 6 years might be conditionally divided into some periods. About the age of 13-14 years, the spectral structure of heart rate variability reached the level of adult humans but is accompanied with features of functional strengthening in regulative systems. About the age of 15-16 years, maturation of indices received in quiet state (heart rate, stroke volume, spectral and statistical parameters of heart rate variability) is reached. At the same time, the functional maturation of heart rate regulating systems was complete thereby providing adaptive response of the organism during the implementation of functional tests. Functional maturation of peripheral blood pressure and the systems of its regulation completed after 16 years.