Effect of orthostasis on the regulation of skin blood flow in upper and lower extremities in human.

OBJECTIVE: The research is aimed to investigate interactions between cardiovascular signals and to assess contributions of central and local mechanisms to skin blood flow regulation in upper and lower extremities at rest and under orthostasis. METHODS: Heart rate variability, respiration, forearm, and foot skin blood flow were assessed at rest and during postural test in 25 healthy volunteers. Spectral analysis was performed. Phase synchronization degree of analyzed signals was determined by group phase wavelet coherence function. RESULTS: Skin blood flow was lower on foot at rest and during postural test than on forearm. High-frequency component of heart rate variability was higher at ~0.3 Hz during postural test versus rest. Blood flow oscillation amplitudes on the foot were lower in frequency range including respiratory interval at rest than on forearm. Postural exposure increased amplitude of foot blood flow oscillations in respiratory interval and decreased amplitudes in cardiac interval versus rest. Orthostasis increased group wavelet phase coherence between foot blood flow and heart rate variability or respiration, as well as between forearm and foot blood flow at 0.3 Hz corresponding to respiration. CONCLUSIONS: The contribution of central mechanisms associated with respiration to blood flow regulation increased in lower extremities during orthostasis.

Delayed kinetics of phagocytosis related respiratory burst in blood is a distinctive feature of moderate exacerbation of bronchial asthma.

Atopic bronchial asthma based on allergy history and chronic inflammation is hazardous to patients due to the risk of exacerbation. The sign of severe exacerbation is considered an abundant number and high activity of granulocytes in respiratory system and blood. Relationships between the ability of cells in blood to produce reactive radicals and their metabolites and the severity of asthma remain largely unclear. Kinetics of respiratory burst evoked by microbe particles in blood samples of patients was studied to reveal the most significant predictors distinguishing states of moderate exacerbation and out of exacerbation. Asthmatic patients with exacerbation (n = 18) or out of exacerbation (n = 62) and healthy individuals (n = 43) were characterized on respiratory function, cell count in blood and kinetics of generation of reactive radicals and their metabolites during phagocytosis. Mean values of respiratory parameters forced expiratory volume in 1 s and peak expiratory flow rate in patients with exacerbation were significantly differed compared with same of patients out of exacerbation and healthy individuals. Mean values of cell count in blood did not significantly differed in patients with exacerbation and out of exacerbation. Receiver operating characteristic analysis showed that both cell count and respiratory indexes did not discriminate patients with exacerbation from out of exacerbation. A delayed response to opsonized zymosan was revealed in patients with exacerbation compared to other examinees: lengthened lag-time and Tmax, reduced production of reactive species. Tmax was the most statistically significant predictor to discriminate bronchial asthma exacerbation from bronchial asthma out of exacerbation (area under curve >90%, p < 10-5) and controls (area under curve >80%, p < 10-5). Thus kinetic parameters of the phagocyte response to opsonized zymosan in the whole blood are the best predictors of bronchial asthma exacerbation in comparison with respiratory parameters and blood cell count. This test can be used for immunological monitoring of bronchial asthma status to prevent exacerbation.

The influence of the DNA torque on the dynamics of transcription bubbles in plasmid PTTQ18.

In this work, we study numerically the influence of the DNA torque on the movement of transcription bubbles in the potential field formed by the sequence of plasmid PTTQ18. To imitate the movement, we apply a modified sine-Gordon equation with the two additional terms that describe the effects of dissipation and the action of the DNA torsion torque, and with the coefficients that depend on the sequence of bases. We obtain the trajectories of the transcription bubbles and investigate the dependence of the trajectories on the initial bubble velocity and the DNA torsion torque. It is shown that not the initial bubble velocity but the DNA torsion torque governs the trajectories of the transcription bubbles.

Accelerated reactivity of blood granulocytes in patients with atopic bronchial asthma out of exacerbation.

Reactive oxygen species (ROS) are important in bronchial asthma (BA) pathogenesis owing to accumulation of activated granulocytes in the lungs. But the ROS-producing activity of the cells is insufficiently understood in the blood of BA patients. This study analyzes the kinetics of phagocyte respiratory burst in the blood to improve the methods of BA patients monitoring. Patients with atopic BA out of exacerbation (n=60) and healthy controls (n=43) were recruited. The time-course of respiratory response to opsonized zymosan (OZ) was recorded in the whole blood using luminol-dependent chemiluminescence (CL), and its activation kinetics (lag-time, rate, amplitude, ROS production) was calculated. The discriminative power of ROS generation kinetics was defined by Receiver Operating Characteristic (ROC) curve analysis. Standard physiological respiratory parameters of patients did not differ from the controls. More rapid response to OZ was recorded in BA patient samples versus the controls. The primed state of phagocytes in the blood of BA patients was corroborated by significant weakening formyl peptide priming effect. The adhesion of granulocytes to cultured human endothelial cells was two-fold higher in BA patients versus controls. ROC curve analysis exhibited good discriminative effectiveness of the CL kinetics to compare BA individuals with the controls. The highest power (86% sensitivity and 90% specificity) was achieved at a linear combination of the parameters. We assume that the assessment of phagocyte reactivity based on the analysis of the response kinetic profile is a good test for monitoring of the state in BA patients.

A sensitive and specific lateral flow assay for rapid detection of antibodies against glycoprotein B of Aujeszky's disease virus.

A direct double antibody lateral flow assay (DDA-gB-LFA) for the detection of antibodies against the glycoprotein B (gB) of Aujeszky's disease virus (ADV) in swine sera was developed. A native ADV gB was used for the preparation of a conjugate with colloidal gold particles and the immobilization on the strip membrane. The gB purified from ADV virions by immunoaffinity chromatography retained its native epitope structure after adsorption on the nitrocellulose membrane and the surface of colloidal gold particles. The diagnostic specificity and sensitivity of the DDA-gB-LFA were evaluated using 236 field swine sera. The diagnostic specificity and sensitivity of the DDA-gB-LFA compared to a commercially available gB-based ELISA were 98.0% and 98.6%, respectively, when determined with the use of the reader-detection mode, and 98.0% and 93.5%, respectively, when determined using visual detection. The DDA-gB-LFA provides a rapid, sensitive, and specific determination of ADV gB-directed antibodies in sera and can be used for the detection of ADV-exposed swine.

Nicotinic receptor involvement in regulation of functions of mouse neutrophils from inflammatory site.

Participation of nicotinic acetylcholine receptors (nAChRs) in functioning of polymorphonuclear neutrophils (PMNs) isolated from inflammatory site of mice and expression of different nAChR subunits were studied. Nicotine and acetylcholine (ACh) modified respiratory burst induced by a chemotactic peptide N-formyl-MLF in neutrophils of male (but not female) mice. Antagonists of nAChRs α-cobratoxin (αCTX), α-conotoxins MII and [A10L]PnIA at concentrations of 0.01-5µM, 0.2µM and 1µM, respectively, eliminated nAChR agonist effects. ACh also affected adhesion of PMNs, this effect was also prevented by αCTX (100nM) and MII (1nM). Neutrophils of female mice after chronic nicotine consumption acquired sensitivity to nAChR agonists. Changes of free intracellular Ca(2+) concentration in neutrophils under the action of nAChR ligands were analyzed. In cells with no Ca(2+) oscillations and relatively low resting level of intracellular Ca(2+), nicotine triggered Ca(2+)-spikes, the lag of the response shortened with increasing nicotine concentration. A nicotinic antagonist caramiphen strongly decreased the effect of nicotine. RT-PCR analysis revealed mRNAs of α2, α3, α4, α5, α6, α7, α9, ß2, ß3, and ß4 nAChR subunits. Specific binding of [(125)I]-α-bungarotoxin was demonstrated. Thus in view of the effects and binding characteristics the results obtained suggest a regulatory role of α7, α3ß2 or α6* nAChR types in specific functions of PMNs.

Wavelet phase coherence analysis of the skin blood flow oscillations in human.

The wavelet phase coherence of oscillations in the peripheral blood flow of contralateral skin sites was studied in 20 healthy subjects. Skin perfusion was registered simultaneously on similar regions of the outer sides of the right and left forearms by the laser Doppler flowmetry technique. To estimate the reliability of the obtained wavelet phase coherence values we applied the comparative method using amplitude-adjusted Fourier transform surrogates. High median values (0.63 and 0.59) of the wavelet phase coherence were obtained for the frequency intervals of respiratory (0.145-0.6Hz) and cardiac (0.6-2Hz) rhythms in 18 and 20 participants, respectively. In all the 20 participants we detected high and reliable values (Ме=0.72) of the wavelet phase coherence for skin blood flow oscillations in the myogenic interval (0.052-0.145Hz). Additionally, we demonstrated high wavelet phase coherence in the neurogenic (0.021-0.052Hz) and endothelial (0.0095-0.021Hz) intervals in 8 and 7 participants, respectively. The corresponding medians of the reliable wavelet phase coherence values for these intervals were 0.74 and 0.82. The obtained results suggest that the microvascular blood flow possesses not only the local mechanisms of generating low-frequency blood flow oscillations, but also a central mechanism, which is likely to synchronize low-frequency oscillations throughout the whole cardiovascular system.