Apelin as a Potential Regulator of Peak Athletic Performance.

Apelin, as a cardiokine/myokine, is emerging as an important regulator of cardiac and skeletal muscle homeostasis. Loss of apelin signaling results in premature cardiac aging and sarcopenia. However, the contribution of apelin to peak athletic performance remains largely elusive. In this paper, we assessed the impact of maximal cardiorespiratory exercise testing on the plasma apelin levels of 58 male professional soccer players. Circulating apelin-13 and apelin-36, on average, increased transiently after a single bout of treadmill exercise; however, apelin responses (Δapelin = peak - baseline values) showed a striking interindividual variability. Baseline apelin-13 levels were inversely correlated with those of Δapelin-13 and Δapelin-36. Δapelin-13 showed a positive correlation with the maximal metabolic equivalent, relative maximal O2 consumption, and peak circulatory power, whereas such an association in the case of Δapelin-36 could not be detected. In conclusion, we observed a pronounced individual-to-individual variation in exercise-induced changes in the plasma levels of apelin-13 and apelin-36. Since changes in plasma apelin-13 levels correlated with the indicators of physical performance, whole-body oxygen consumption and pumping capability of the heart, apelin, as a novel exerkine, may be a determinant of peak athletic performance.

Adrenal, Gonadal and Peripherally Steroid Changes in Response to Extreme Physical Stress for Characterizing Load Capacity in Athletes.

Athletes are often exposed to extreme physical stress during training or competitions. The consequent activation of the hypothalamus-hypophysis-adrenal (HPA) axis results in intensified steroid hormone production in the adrenal cortex. We determined the impact of an acute extreme physical stress on adrenal and gonadal steroidogenesis in healthy male professional athletes (n = 40). The subjects underwent an extreme physical load test until total voluntary fatigue between 14:00 and 18:00 when the hormone levels are relatively stable. Blood was taken before the start (baseline), at the peak load (peak), and 30 min following completion of the exercise (recovery). The vital parameters, lactate levels, and blood levels of the 14 steroid hormones were recorded. The multivariate statistical analysis of the results revealed that all monitored hormone levels increased upon stress. Significant changes in steroid concentrations were detected at peak versus baseline, peak versus recovery, and at baseline versus recovery. The mineralocorticoid (including aldosterone and corticosterone), glucocorticoid (11-deoxycortisol and cortisol), and androgen (androstenedione, dehydroepiandrosterone, and dehydroepiandrosterone sulfate) pathways, as well as gonadal testosterone synthesis are activated simultaneously under extreme physical load. The profiling of adrenal and gonadal steroid biosynthesis in athletes may help the characterization of their loading capacity.

Comparison of the Cardiovascular Effects of Extreme Psychological and Physical Stress Tests in Male Soccer Players.

BACKGROUND: The purpose of our study was to compare the physiological effects of extreme physical and psychological stress tests in male soccer players, since these two types of stress apply to athletes with high performance requirements. METHODS: A total of 63 healthy male soccer players participated in this study, all of whom underwent both of the tests. A physical stress test was carried out in an exercise physiology laboratory, where subjects completed an incremental treadmill running test to full exhaustion, and a psychological test was performed in a military tactical room, where subjects met a street offence situation. Heart rate variability (HRV) and blood pressure (BP) were recorded directly before, immediately after, and 30 min after the stress tests. RESULTS: The majority of HRV indices changed significantly in both stress protocols. Inverse, significant changes (positive for the physical test, negative for the psychological test, p < 0.001) were found when comparing the alterations of HRV indices between the tests. Significant differences were found in the changes in systolic (p = 0.003) and diastolic (p < 0.001) BP between the test protocols, and also between the baseline and post-test measurements (p < 0.001). CONCLUSION: Both HRV and BP are sensitive physiological parameters to measure the impact of extreme physical and/or psychological stress.

[Diagnostic challenges in pediatric cow's milk protein allergy]. / A gyermekkori tehéntejfehérje-allergia diagnosztikai kihívásai.

Introduction and aim: The aim of our research is to evaluate and compare commonly performed diagnostic tests, and to examine the psychological disorders induced by this food allergy. Children with symptoms suggesting cow's milk protein allergy were included in this study (n = 47). Blood and saliva samples were collected from the participants. Parents were asked to fill in a questionnaire constructed by the research team (containing the DSM-5 symptoms checklist about attention deficit hyperactivity disorder). Method: One of the most widely used diagnostic tool is the skin allergy test, which was performed in 47 subjects (n = 47, mean age: 7.36 years); only 2 children showed positive test result for cow's milk. Lymphocyte transformation test was observed to be positive in 8 children (17%), 4 subjects demonstrated questionable results. In our sub-study about psychological symptoms (n = 43, mean age: 7.88 years), the score was according to the attention deficit hyperactivity disorder symptom checklist before the diet (6.88, SD: 4.43) and showed significant decrease after 3 months of the elimination diet (4.48, SD: 3.69, p = 0.001). Scores of children with sleep disorder (10.62, SD: 4.23) also represented a significant reduction after 3 months of the diet (6.69, SD: 4.59, p = 0.009). Salivary cortisol levels did not show significant changes before and after elimination diet. Results: According to our data, skin allergy testing and lymphocyte transformation test are not reliable diagnostic tools for establishing the diagnosis. Conclusion: We conclude that a significant improvement in clinical symptoms can only be achieved with a strict elimination diet. Orv Hetil. 2019; 160(33): 1311-1318.

Advanced online mass spectrometry detection of proteins separated by capillary isoelectric focusing after sequential injection.

Capillary isoelectric focusing hyphenated with mass spectrometry detection, following the sequential injection of the carrier ampholytes and the sample zone, is highly efficient for the characterization of proteins. The main advantage of the sequential injection protocol is that ampholytes, with pH ranges, which are not supposed to cover the isoelectric points of the sample components, can be used for separation. The method then allows online mass spectrometry detection of separated analytes either in the absence (substances that have left the pH gradient) or in the presence of low-level ampholytes (substances that are migrating within the pH gradient). The appearance of the substances within, or outside the pH gradient depends on, e.g., the composition of the ampholytes (broad or narrow pH range) or on the composition of electrolyte solutions. The experiments performed in coated capillaries (with polyvinyl alcohol or with polyacrylamide) show that the amount and the injection length of the ampholytes influence the length of the pH gradient formed in the capillary.