Acta physiologica Hungarica最新文献

Expiratory flow limitation can develop in parallel with the progression of COPD, and as a consequence, dynamic hyperinflation and lung mechanical abnormalities can develop. Dynamic hyperinflation can cause increased breathlessness and reduction in exercise tolerance. Achievement of critical inspiratory reserve volume is one of the main factors in exercise intolerance. Obesity has specific lung mechanical effects. There is also a difference concerning gender and dyspnoea. Increased nerve activity is characteristic in hyperinflation. Bronchodilator therapy, lung volume reduction surgery, endurance training at submaximal intensity, and heliox or oxygen breathing can decrease the degree of dynamic hyperinflation.

Unlabelled: Mitochondrial functions have a major impact on T-cell functionality. In this study we characterized whether mitochondrial function in the neonatal T-cells differs from that in the adult T-cells during short T-cell activation.

Methods: We used flow cytometry methods to test mitochondrial mass and to monitor mitochondrial Ca²⁺ levels, mitochondrial potential and superoxide generation in parallel with cytoplasmic Ca²⁺ levels during phythohaemagglutinine-induced activation of CD4+ and CD8+ T-cells of 12 term neonates and 11 healthy adults.

Results: Baseline mitochondrial mass of CD4+ and CD8+ cells was lower in the neonate than in the adult. In comparison with the adult, neonatal resting CD4+ T-cells had lower cytoplasmic Ca²⁺ levels and this was associated with normal activation induced Ca²⁺-response. During short-term activation cytoplasmic Ca²⁺-response was lower in neonatal than in adult CD8+ T-cells. Mitochondrial Ca²⁺ uptake was increased in CD4+ neonatal T cells while it decreased in CD8+ T-cells. Mitochondrial depolarization was increased in CD4+ and decreased in CD8+ neonatal T-cells compared to adults. Superoxide generation was higher and equal in neonatal CD4+ and CD8+ cells, respectively, compared to the adult ones.

Conclusion: Our data suggest that neonatal T-cells exhibit marked differences in mitochondrial function and superoxide generation compared to adult T-cells.

The purpose of this study was to determine whether tissue oxygen indices (TOIs) in two muscle groups oscillated and were synchronized in repetition of impulse exercise with high intensity. Five impulse exercises of 400 watts for 10 s were repeated with intervals of 6 min. During this period, TOI was determined by near-infrared spectroscopy in the vastus lateralis and gastrocnemius muscles. TOIs in the two muscles oscillated at rest. The TOIs rapidly decreased during each impulse exercise and then recovered and overshot after each impulse. The TOIs oscillated during each interval period. During this test period, coherent and phase differences were determined. There was high coherence between TOIs in the two muscles with a peak value at 0.019 Hz. There was a phase difference of -45 ± 32.4 degrees between TOIs in the two muscles. This phase difference corresponded to about 6 s in time scale. It seemed from this time delay that impulse exercise was not a trigger factor for the starting point of TOIs in the two muscles. It has been concluded that TOIs oscillate and are synchronized between two muscles in repetition of impulse exercise with high intensity.

Unlabelled: Left atrial (LA) distension has been demonstrated to be linked with aortic stiffness in different patient populations. Three-dimensional (3D) speckle-tracking echocardiography (STE) seems to be a promising tool for volumetric and functional evaluation of the LA. The aim of the present study was to determine whether correlations exist between 3DSTE-derived LA volume-based and strain parameters characterizing all phasic functions of the LA and echocardiographic aortic elastic properties in healthy subjects. The study included 19 healthy volunteers (mean age: 37.9 ± 11.4 years, 11 men) who had undergone complete two-dimensional (2D) Doppler transthoracic echocardiography extended with the assessment of aortic elastic properties and 3DSTE.

Results: None of LA volumes correlated with echocardiographic aortic elastic properties. Active atrial stroke volume correlated with aortic stiffness index (ASI, r = 0.45, p = 0.05). None of other volume-based functional properties significantly correlated with aortic stiffness parameters. Global peak 3D strain correlated with aortic strain (r = ‒0.46, p = 0.05). global radial pre-atrial contraction strain correlated with ASI (r = ‒0.49, p = 0.04) and AS (r = ‒0.50, p = 0.04).

Conclusions: Correlations exist between 3DSTE-derived LA functional parameters and eschocardiographic aortic elastic properties in healthy subjects.

Purpose: Deformability/rheologic behavior of erythrocytes are related to near-surface membrane fluidity. Specific agents can increase erythrocyte membrane fluidity in order to adjust hemodynamics in cardiovascular diseases. Grapefruit flavanone naringenin has been proposed for potential use in an alternative therapy of cardiovascular conditions. In respect to this, we assessed here effects of two nutritionally relevant concentrations of naringenin (0.1 and 1 μg/ml) on near-surface membrane fluidity in human erythrocytes.

Methods: We used electron paramagnetic resonance spectroscopy and fatty acid spin probes (5-DS and 7-DS), the spectra of which are dependent on membrane fluidity.

Results: The results showed a significant (p = 0.029) increase of membrane fluidity near the hydrophilic surface in erythrocytes treated with higher concentration of naringenin. In the deeper layer, just below the erythrocyte membrane phospholipid heads, both lower and higher concentration of naringenin significantly increased membrane fluidity (p = 0.036 and p = 0.028, respectively).

Conclusions: These data document the positive and dose dependent effect of naringenin on near-surface membrane fluidity in human erythrocytes, recommending its use in the cardiovascular conditions characterized by disturbed hemodynamics.

Unlabelled: Tissue level myocardial perfusion is one of the most important prognostic factors after successful recanalisation of the occluded coronary artery in patients suffering acute ST elevation myocardial infarction (STEMI). The primary objective of the present study was to examine the relationship between videodensitometric myocardial perfusion parameters as assessed on coronary angiograms directly following successful recanalization therapy and magnetic resonance imaging (MRI)-derived myocardial tissue loss late after STEMI. The study comprised 29 STEMI patients. Videodensitometric parameter G(max)/T(max) was calculated to characterize myocardial perfusion, derived from the plateau of grey-level intensity (G(max)), divided by the time-to-peak intensity (Tmax). Myocardial loss index (MLI) was assessed by cardiac MRI following 376 ± 254 days after PCI.

Results: Significant correlations could be demonstrated between MLI and G(max) (r = 0.36, p = 0.05) and G(max)/T(max) (r = 0.40, p = 0.03) using vessel masking. Using receiver operating characteristic curve analysis, G(max)/T(max) < 2.17 predicted best MLI = 0.3, 0.4, 0.5 and 0.6 with good sensitivity and specificity data, while G(max)/T(max) < 3.25 proved to have a prognostic role in the prediction of MLI = 0.7.

Conclusions: Selective myocardial tissue level perfusion quantitative measurement method is feasible and can serve as a good predictor of myocardial tissue loss following STEMI and revascularization therapy.