Resting heart rate as a predictor of metabolic dysfunctions in obese children and adolescents

Background: Recent studies have identified that a higher resting heart rate (RHR) is associated with elevated blood pressure, independent of body fatness, age and ethnicity. However, it is still unclear whether RHR can also be applied as a screening for other risk factors, such as hyperglycemia and dyslipidemia. Thus, the purpose of the presented study was to analyze the association between RHR, lipid profile and fasting glucose in obese children and adolescents. Methods: The sample was composed of 180 obese children and adolescents, aged between 7-16 years. Whole-body and segmental body composition were estimated by Dual-energy X-ray absorptiometry. Resting heart rate (RHR) was measured by heart rate monitors. The fasting blood samples were analyzed for serum triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and glucose, using the colorimetric method. Results: Fasting glucose, TC, triglycerides, HDL-C, LDL-C and RHR were similar in both genders. The group of obese subjects with a higher RHR presented, at a lower age, higher triglycerides and TC. There was a significant relationship between RHR, triglycerides and TC. In the multivariate model, triglycerides and TC maintained a significant relationship with RHR independent of age, gender, general and trunk adiposity. The ROC curve indicated that RHR has a high potential for screening elevated total cholesterol and triglycerides as well as dyslipidemia. Conclusion: Elevated RHR has the potential to identify subjects at an increased risk of atherosclerosis development.

Effects of circuit-based exercise programs on the body composition of elderly obese women

Aim: The aim of this study was to investigate the impact of circuit-based exercise on the body composition in obese older women by focusing on physical exercise and body weight (BW) gain control in older people. Methods: Seventy older women (>60 years old) voluntarily took part in the study. Participants were randomized into six different groups according to body mass index (BMI): appropriate weight (AW) control (AWC) and trained (AWT) groups, overweight (OW) control (OWC) and trained (OWT) groups, and obesity (O) control (OC) and trained (OT) groups. The exercise program consisted of 50 minutes of exercise three times per week for 12 weeks. The exercises were alternated between upper and lower body using rest between sets for 40 seconds with intensity controlled by heart rate (70% of work). The contraction time established was 5 seconds to eccentric and concentric muscular action phase. The following anthropometric parameters were evaluated: height (m), body weight (BW, kg), body fat (BF, %), fat mass (FM, kg), lean mass (LM, kg), and BMI (kg/m(2)). Results: The values (mean +/- standard deviation [SD]) of relative changes to BW (-8.0% +/- 0.8%), BF (-21.4% +/- 2.1%), LM (3.0% +/- 0.3%), and FM (-31.2% +/- 3.0%) to the OT group were higher (P < .05) than in the AWT (BW: -2.0% +/- 1.1%; BF: -4.6% +/- 1.8%; FM: -7.0% +/- 2.8%; LM: 0.2% +/- 1.1%) and OWT (BW: -4.5% +/- 1.0%; BF: -11.0% +/- 2.2%; FM: -16.1% +/- 3.2%; LM: -0.2% +/- 1.0%) groups; additionally, no differences were found for C groups. While reduction (P < .03) in BMI according to absolute values was observed for all trained groups (AWT: 22 +/- 1 versus 21 +/- 1; OWT: 27 +/- 1 versus 25 +/- 1, OT: 34 +/- 1 versus 30 +/- 1) after training, no differences were found for C groups. Conclusion: In summary, circuit-based exercise is an effective method for promoting reduction in anthropometrics parameters in obese older women.

Learning generalization in problem solving by a blue-fronted parrot (Amazona aestiva)

Pepperberg (The Alex studies: cognitive and communicative abilities of gray parrots. Harvard University Press, Cambridge;1999) showed that some of the complex cognitive capabilities found in primates are also present in psittacine birds. Through the replication of an experiment performed with cotton-top tamarins (Saguinus oedipus oedipus) by Hauser et al. (Anim Behav 57:565-582; 1999), we examined a blue-fronted parrot`s (Amazona aestiva) ability to generalize the solution of a particular problem in new but similar cases. Our results show that, at least when it comes to solving this particular problem, our parrot subject exhibited learning generalization capabilities resembling the tamarins`.

Semi-supervised learning guided by the modularity measure in complex networks

Semi-supervised learning techniques have gained increasing attention in the machine learning community, as a result of two main factors: (1) the available data is exponentially increasing; (2) the task of data labeling is cumbersome and expensive, involving human experts in the process. In this paper, we propose a network-based semi-supervised learning method inspired by the modularity greedy algorithm, which was originally applied for unsupervised learning. Changes have been made in the process of modularity maximization in a way to adapt the model to propagate labels throughout the network. Furthermore, a network reduction technique is introduced, as well as an extensive analysis of its impact on the network. Computer simulations are performed for artificial and real-world databases, providing a numerical quantitative basis for the performance of the proposed method.

AGE INFLUENCE ON THE HEART RATE BEHAVIOR ON THE REST-EXERCICIO TRANSITION: AN ANALYSIS BY DELTAS AND LINEAR REGRESSION

Background: Changes in heart rate during rest-exercise transition can be characterized by the application of mathematical calculations, such as deltas 0-10 and 0-30 seconds to infer on the parasympathetic nervous system and linear regression and delta applied to data range from 60 to 240 seconds to infer on the sympathetic nervous system. The objective of this study was to test the hypothesis that young and middle-aged subjects have different heart rate responses in exercise of moderate and intense intensity, with different mathematical calculations. Methods: Seven middle-aged men and ten young men apparently healthy were subject to constant load tests (intense and moderate) in cycle ergometer. The heart rate data were submitted to analysis of deltas (0-10, 0-30 and 60-240 seconds) and simple linear regression (60-240 seconds). The parameters obtained from simple linear regression analysis were: intercept and slope angle. We used the Shapiro-Wilk test to check the distribution of data and the "t" test for unpaired comparisons between groups. The level of statistical significance was 5%. Results: The value of the intercept and delta 0-10 seconds was lower in middle age in two loads tested and the inclination angle was lower in moderate exercise in middle age. Conclusion: The young subjects present greater magnitude of vagal withdrawal in the initial stage of the HR response during constant load exercise and higher speed of adjustment of sympathetic response in moderate exercise.

Protein quality control disruption by PKC beta II in heart failure: rescue by the selective PKC beta II inhibitor, beta IIV5-3

Myocardial remodeling and heart failure (HF) are common sequelae of many forms of cardiovascular disease and a leading cause of mortality worldwide. Accumulation of damaged cardiac proteins in heart failure has been described. However, how protein quality control (PQC) is regulated and its contribution to HF development are not known. Here, we describe a novel role for activated protein kinase C isoform beta II (PKC beta II) in disrupting PQC. We show that active PKC beta II directly phosphorylated the proteasome and inhibited proteasomal activity in vitro and in cultured neonatal cardiomyocytes. Importantly, inhibition of PKC beta II, using a selective PKC beta II peptide inhibitor (beta IIV5-3), improved proteasomal activity and conferred protection in cultured neonatal cardiomyocytes. We also show that sustained inhibition of PKC beta II increased proteasomal activity, decreased accumulation of damaged and misfolded proteins and increased animal survival in two rat models of HF. Interestingly, beta IIV5-3-mediated protection was blunted by sustained proteasomal inhibition in HF. Finally, increased cardiac PKC beta II activity and accumulation of misfolded proteins associated with decreased proteasomal function were found also in remodeled and failing human hearts, indicating a potential clinical relevance of our findings. Together, our data highlights PKC beta II as a novel inhibitor of proteasomal function. PQC disruption by increased PKC beta II activity in vivo appears to contribute to the pathophysiology of heart failure, suggesting that PKC beta II inhibition may benefit patients with heart failure. (218 words)

Aging reduces complexity of heart rate variability assessed by conditional entropy and symbolic analysis

Increasing age is associated with a reduction in overall heart rate variability as well as changes in complexity of physiologic dynamics. The aim of this study was to verify if the alterations in autonomic modulation of heart rate caused by the aging process could be detected by Shannon entropy (SE), conditional entropy (CE) and symbolic analysis (SA). Complexity analysis was carried out in 44 healthy subjects divided into two groups: old (n = 23, 63 +/- A 3 years) and young group (n = 21, 23 +/- A 2). It was analyzed SE, CE [complexity index (CI) and normalized CI (NCI)] and SA (0V, 1V, 2LV and 2ULV patterns) during short heart period series (200 cardiac beats) derived from ECG recordings during 15 min of rest in a supine position. The sequences characterized by three heart periods with no significant variations (0V), and that with two significant unlike variations (2ULV) reflect changes in sympathetic and vagal modulation, respectively. The unpaired t test (or Mann-Whitney rank sum test when appropriate) was used in the statistical analysis. In the aging process, the distributions of patterns (SE) remain similar to young subjects. However, the regularity is significantly different; the patterns are more repetitive in the old group (a decrease of CI and NCI). The amounts of pattern types are different: 0V is increased and 2LV and 2ULV are reduced in the old group. These differences indicate marked change of autonomic regulation. The CE and SA are feasible techniques to detect alteration in autonomic control of heart rate in the old group.

Sleeping difficulties reported by patients with heart failure

The study aimed to describe the reports of heart failure patients on the factors that cause difficulties to sleep and the association of these factors with the quality of sleep. This cross-sectional study involved a non-probabilistic sample of 400 patients (mean age 57.8 years, 64.8% were men, average education of 6.1 years, 82.5% in functional class II or III) with heart failure. The main factors associated with sleeping difficulty were: nocturia, interrupted sleep at night and breathing difficulty. Sleeping difficulties in heart failure patients are diverse and there is an association between these difficulties and quality of sleep. Most of these disorders warrant professional nursing interventions.

Global and Regional Ventricular Repolarization Study by Body Surface Potential Mapping in Patients with Left Bundle-Branch Block and Heart Failure Undergoing Cardiac Resynchronization Therapy

Background: The controversial effects promoted by cardiac resynchronization therapy (CRT) on the ventricular repolarization (VR) have motivated VR evaluation by body surface potential mapping (BSPM) in CRT patients. Methods: Fifty-two CRT patients, mean age 58.8 +/- 12.3 years, 31 male, LVEF 27.5 +/- 9.2, NYHA III-IV heart failure with QRS181.5 +/- 14.2 ms, underwent 87-lead BSPM in sinus rhythm (BASELINE) and biventricular pacing (BIV). Measurements of mean and corrected QT intervals and dispersion, mean and corrected T peak end intervals and their dispersion, and JT intervals characterized global and regional (RV, Intermediate, and LV regions) ventricular repolarization response. Results: Global QTm (P < 0.001) and QTcm (P < 0.05) were decreased in BIV; QTm was similar across regions in both modes (P = ns); QTcm values were lower in RV/LV than in Intermediate region in BASELINE and BIV (P < 0.001); only RV/Septum showed a significant difference (P < 0.01) in the BIV mode. QTD values both of BASELINE (P < 0.01) and BIV (P < 0.001) were greater in the Intermediate than in the LV region. CRT effect significantly reduced global/regional QTm and QTcm values. QTD was globally decreased in RV/LV (Intermediate: P = ns). BIV mode significantly reduced global T peak end mean and corrected intervals and their dispersion. JT values were not significant. Conclusions: Ventricular repolarization parameters QTm, QTcm, and QTD global/regional values, as assessed by BSPM, were reduced in patients under CRT with severe HF and LBBB. Greater recovery impairment in the Intermediate region was detected by the smaller variation of its dispersion.

Pulmonary hypertension diagnosed by right heart catheterisation in sickle cell disease

Recent studies have recognised the importance of pulmonary hypertension (PH) in sickle cell disease (SCD). The aim of this study was to determine the prevalence and prognostic impact of PH and its features in patients with SCD. 80 patients with SCD underwent baseline clinical evaluation, laboratory testing, 6-min walk tests (6MWTs) and echocardiography. Patients with a peak tricuspid regurgitant jet velocity (TRV) of >= 2.5 m.s(-1) were further evaluated through right heart catheterisation (RHC) to assure the diagnosis of PH. Our study evidenced a 40% prevalence of patients with elevated TRV at echocardiography. RHC (performed in 25 out of 32 patients) confirmed PH in 10% (95% CI 3.4-16.5%) of all patients, with a prevalence of post-capillary PH of 6.25% (95% CI 0.95-11.55%) and pre-capillary PH of 3.75% (95% CI -0.4-7.9%). Patients with PH were older, had worse performance in 6MWTs, and more pronounced anaemia, haemolysis and renal dysfunction. Survival was shorter in patients with PH. Our study reinforced the use of echocardiography as a screening tool for PH in SCD and the mandatory role of RHC for proper diagnosis. Our findings confirmed the prognostic significance of PH in SCD as its association to pronounced haemolytic profile.

Bias and learning in temporal binding: intervals between actions and outcomes are compressed by prior bias

It has consistently been shown that agents judge the intervals between their actions and outcomes as compressed in time, an effect named intentional binding. In the present work, we investigated whether this effect is result of prior bias volunteers have about the timing of the consequences of their actions, or if it is due to learning that occurs during the experimental session. Volunteers made temporal estimates of the interval between their action and target onset (Action conditions), or between two events (No-Action conditions). Our results show that temporal estimates become shorter throughout each experimental block in both conditions. Moreover, we found that observers judged intervals between action and outcomes as shorter even in very early trials of each block. To quantify the decrease of temporal judgments in experimental blocks, exponential functions were fitted to participants’ temporal judgments. The fitted parameters suggest that observers had different prior biases as to intervals between events in which action was involved. These findings suggest that prior bias might play a more important role in this effect than calibration-type learning processes.