Placebo and nocebo interventions impact perceived but not actual proprioceptive accuracy.

Changes in performance caused by positive and negative expectations (i.e., placebo and nocebo responses) were found to play an important role in many aspects of motor performance. This study aimed to test the impact of placebo/nocebo responses and the assumed moderating role of dispositional optimism and anxiety on proprioceptive accuracy, an essential aspect of motor functions. 78 undergraduate university students completed questionnaires assessing dispositional optimism, state anxiety, and motivation to cooperate, then were randomly assigned to three experimental groups. A sham subliminal electric stimulation was applied with claimed positive (placebo group, n = 26), negative (nocebo group, n = 26) or neutral (control group, n = 26) impact on proprioceptive accuracy. Proprioceptive accuracy was measured with active and passive versions of the Joint Position Reproduction task before and after the intervention. Expected and perceived changes in performance were also assessed; changes in state anxiety, optimism, and motivation to cooperate were used as control variables (covariates). Mixed analyses of variance indicated that the experimental manipulation did not affect actual proprioceptive accuracy but impacted expected and perceived performance. Adding the covariates to the models did not substantially change the results. Further, no significant association emerged between actual and perceived change in performance in the active test, and only a weak correlation was found in the passive test. Expected performance did not predict actual performance but predicted perceived performance in both tasks. The results suggest that only perceived (subjective) aspects of proprioceptive accuracy are susceptible to placebo and nocebo interventions.

Sensory and affective aspects of the perception of respiratory resistance.

Perception of airway resistance has a sensory and an affective aspect, i.e., perceived resistance and unpleasantness, respectively. The current study aimed to shed more light on the relationship of these aspects, as well as their malleability to trait-like aspects of body awareness. In a laboratory study, 71 young participants completed two respiratory resistive load discrimination tasks relying on sensory and affective evaluation, respectively, and filled out questionnaires assessing somatosensory amplification, anxiety sensitivity, somatic symptoms distress, and breath awareness. Frequentist and Bayesian statistical analysis revealed no differences in discrimination accuracy with respect to the sensory and affective aspect of perceived resistance. Psychological traits were not associated with accuracy scores. In conclusion, affective evaluation of respiratory load is as accurate as sensory evaluation. Neither sensory not affective accuracy is influenced by various aspects of body awareness.

Apelin promotes blood and lymph vessel formation and the growth of melanoma lung metastasis.

Apelin, a ligand of the APJ receptor, is overexpressed in several human cancers and plays an important role in tumor angiogenesis and growth in various experimental systems. We investigated the role of apelin signaling in the malignant behavior of cutaneous melanoma. Murine B16 and human A375 melanoma cell lines were stably transfected with apelin encoding or control vectors. Apelin overexpression significantly increased melanoma cell migration and invasion in vitro, but it had no impact on its proliferation. In our in vivo experiments, apelin significantly increased the number and size of lung metastases of murine melanoma cells. Melanoma cell proliferation rates and lymph and blood microvessel densities were significantly higher in the apelin-overexpressing pulmonary metastases. APJ inhibition by the competitive APJ antagonist MM54 significantly attenuated the in vivo pro-tumorigenic effects of apelin. Additionally, we detected significantly elevated circulating apelin and VEGF levels in patients with melanoma compared to healthy controls. Our results show that apelin promotes blood and lymphatic vascularization and the growth of pulmonary metastases of skin melanoma. Further studies are warranted to validate apelin signaling as a new potential therapeutic target in this malignancy.

Elimination of bacterial DNA during RNA isolation from sputum: Bashing bead vortexing is preferable over prolonged DNase treatment.

Sputum often contains large amounts of contaminating bacterial DNA that, if not eliminated during RNA isolation, may interfere with gene expression studies. During RNA isolation only repeated DNase treatment can effectively remove contaminating bacterial DNA from samples, but this compromises RNA quality. In this study we tested alternative methods to facilitate the removal of DNA and improve the quality of RNA obtained. Sputum samples obtained from patients with chronic obstructive pulmonary disease were processed with dithiothreitol and subjected to various RNA isolation methods, yet with modified protocols. Modifications included prolonged DNase treatment or vortexing of sputum cells in the presence of beads prior to RNA isolation. Bacterial DNA contamination was tested by PCR using universal bacterial primers, while RNA quality was assessed by real-time PCR using GAPDH primers for amplicons of different length. We found that the RNeasy Plus Mini kit equipped with the gDNA eliminator spin column was able to completely eliminate bacterial DNA, if sputum cells were lysed in the presence of bashing beads. Notably, compared with the standard protocol, the modified procedure yielded better quality RNA as well, as indicated by improved threshold profiles of qPCR. Bead vortexing of cells was less effective when combined with other RNA isolation methods, and the repeated DNase treatment needed to completely remove contaminating DNA from the samples reduced the quality of RNA markedly. Bead vortexing in combination with certain RNA extraction methods greatly facilitates the isolation of sputum RNA that is free of contaminating bacterial DNA, and is suitable for downstream applications.

Kinetics of Exhaled Carbon Monoxide After Water-pipe Smoking Indoors and Outdoors.

BACKGROUND: Despite accumulating evidence about its adverse health effects, water-pipe tobacco smoking has become very popular among youth. The aim of this study was to compare smoke exposure and the kinetics of exhaled carbon monoxide (eCO) between water-pipe and cigarette smokers under different conditions. METHODS: Using a cross-over study design, changes in eCO and urinary cotinine levels were measured in a cohort of 32 healthy university students after sessions of water-pipe smoking indoors and outdoors. An indoor cigarette smoking session with equal amounts of tobacco was conducted for reference purposes. Both active and passive smokers participated in all sessions. RESULTS: In indoor sessions, we found that among active participants, eCO levels were approximately 7.5-fold higher in water-pipe users than cigarette smokers. eCO levels remained significantly elevated even 10 h after discontinuing water-pipe smoking. Notably, eCO levels in passive water-pipe smokers were in the same range as in active cigarette smokers. Compared with indoor sessions, eCO levels in active water-pipe users were reduced in outdoor environments. Nonetheless, levels were still higher in these subjects than those in active cigarette smokers measured in indoor sessions. Urinary cotinine levels were comparable in active water-pipe and cigarette smokers. CONCLUSIONS: Our results suggest that water-pipe smoking is associated with significantly higher toxicant exposure than cigarette smoking even in outdoor environments. Furthermore, even passive, indoor water-pipe smoke exposure may have significant health hazards compared with those of active cigarette smoking.

Assessment of the Anti-Aging Klotho Protein in Patients with COPD Undergoing Pulmonary Rehabilitation.

Chronic obstructive pulmonary disease (COPD) is associated with the accelerated aging of the lung. The protein klotho has been implicated in longevity, and there is some evidence that it might be involved in the pathomechanism of chronic respiratory diseases. Therefore, we aimed to examine whether the clinical condition of COPD patients is reflected in plasma klotho concentration. As plasma concentration of the protein is modulated by physiological factors that are generally improved during pulmonary rehabilitation, we hypothesized that a complex rehabilitation program may alter plasma klotho concentration. Blood samples were taken from 31 stable COPD patients. Clinical parameters such as respiratory function, 6-minute walking distance (6MWD), impact of disease (CAT), dyspnea, grip strength, chest expansion and breath holding time, smoking history, and body mass index (BMI) were evaluated. 19 patients who participated in a 3-week inpatient rehabilitation program had blood sample collection on the first, third, and last days of the program and had the above functional measurements before and after rehabilitation. Plasma klotho concentration was assessed by enzyme-linked immunosorbent assay. Klotho levels showed no correlation with clinical parameters (FEV1%, 6MWD, grip strength, CAT, smoking history, p > 0.05). Coefficient of variation of klotho measurements was 4.5% between Day 1 and Day 3. Although the rehabilitation resulted in significant improvements in 6MWD, CAT, grip strength, and chest expansion, klotho levels did not change significantly (510.1 ± 149.9 vs. 504.2 ± 139.8 pg/ml, p > 0.05). Plasma klotho concentration can be reliably measured in stable COPD; however, its levels are not correlated with clinical parameters of patients. Despite functional improvement, klotho level remains unchanged during the rehabilitation program.

Comparison of Airway and Systemic Malondialdehyde Levels for Assessment of Oxidative Stress in Cystic Fibrosis.

INTRODUCTION: Oxidative stress plays a pivotal role in the pathogenesis of cystic fibrosis (CF). In this study, airway and systemic oxidative stress was investigated in CF using malondialdehyde (MDA), an established by-product of polyunsaturated fatty acid peroxidation. METHODS: Exhaled breath condensate (EBC), sputum, and plasma were collected from 40 stable CF patients during routine clinical visits and from 25 healthy controls. MDA was measured by high-performance liquid chromatography. RESULTS: MDA levels in sputum (279.8 ± 14.7 vs. 92.7 ± 9.2 nmol/L, p < 0.0001), EBC (139.9 ± 6.7 vs. 71.5 ± 4.3 nmol/L, p < 0.0001), and plasma (176.1 ± 15.9 vs. 129.6 ± 12.9 nmol/L, p < 0.05) were increased in patients with CF compared to healthy controls. MDA measurement in sputum [area under receiver operating characteristic curve (AUC): 0.977, p < 0.0001] or EBC (AUC: 0.94, p < 0.0001) discriminated between patients and controls with greater accuracy than in plasma (AUC: 0.677, p < 0.05). Sputum and EBC MDA levels were elevated in patients with severe pulmonary dysfunction [forced expiratory volume in 1 s (FEV1) <50 % predicted] compared to those with mild-to-moderate functional impairment (FEV1 ≥50 % predicted) (p < 0.05). MDA concentrations in CF patients colonized either with Pseudomonas aeruginosa or with other bacteria were similar (p = NS). The intra- and inter-assay repeatabilities of MDA measurements was similar in all the three types of samples, while the between-visit variability was higher in plasma. CONCLUSIONS: MDA is a potential new airway marker of oxidative stress in patients with CF. Sputum MDA differentiates best between patients and healthy subjects.

Sputum eicosanoid profiling in exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: Eicosanoids are small lipid molecules with diverse biological functions in the airways. OBJECTIVES: The aim of this study was to investigate changes in leukotriene B4 (LTB4), 8-isoprostane, prostaglandin E2 (PGE2) and cysteinyl-leukotriene (cys-LT) levels in the sputum of patients with chronic obstructive pulmonary disease (COPD) at the onset of a severe exacerbation and during the course of recovery. METHODS: Thirty-seven ex-smoker COPD patients suffering an episode of acute exacerbation were enrolled. Samples were taken (i) on hospital admission and (ii) after regular treatment. Twenty-five stable ex-smoker COPD patients served as controls. Eicosanoids were determined by enzyme immunoassay. RESULTS: Sputum PGE2 [39.8 (13.3-103.3) vs. 5.05 (2.3-12.1) pg/ml, p < 0.001], 8-isoprostane [89.5 (36.9-184.7) vs. 29.7 (13.8-68.8) pg/ml, p < 0.01] and LTB4 [587.7 (252.9-774.8) vs. 276.1 (105.4-594.7) pg/ml, p < 0.05] levels were increased in patients with exacerbation compared to stable subjects. After treatment only PGE2 levels decreased significantly [at discharge: 19.6 (4.6-52.5) pg/ml, p < 0.01], the levels of other eicosanoids remained elevated (p = NS). Sputum cys-LT levels were similar in stable patients and in those with exacerbation and treatment did not influence cys-LTs either. There was a significant correlation between PGE2 and sputum neutrophil and lymphocyte cell counts in patients with exacerbation. CONCLUSIONS: Our results suggest that 8-isoprostane, LTB4 and PGE2 but not cys-LTs may be involved in exacerbation-associated inflammatory processes in the airways of patients with COPD. Validation of PGE2 for use as a biomarker of recovery from an exacerbation requires further studies.

Monitoring oxidative stress during chronic obstructive pulmonary disease exacerbations using malondialdehyde.

BACKGROUND AND OBJECTIVE: Oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). In this longitudinal study changes in the level of malondialdehyde (MDA), an end product of polyunsaturated fatty acid peroxidation, were investigated in the airways of patients with acute exacerbation of COPD (AECOPD). METHODS: Levels of MDA were measured in sputum and exhaled breath condensate (EBC) of 34 COPD patients at the time of hospital admission due to an acute exacerbation of the disease, and again following treatment at the time of hospital discharge. MDA was also assessed in 21 stable patients with COPD and 20 healthy controls. Measurements were performed using high-performance liquid chromatography. RESULTS: Sputum MDA levels were significantly increased in AECOPD (220.0 ± 17.5 nmol/L) compared with stable disease (144.6 ± 14.3 nmol/L, P < 0.01) and healthy controls (85.9 ± 11.3 nmol/L, P < 0.001). MDA levels decreased after treatment (190.7 ± 16.3 nmol/L, P < 0.05). In contrast to sputum, EBC MDA levels were comparable between controls, stable COPD patients and AECOPD patients (73.1 ± 5.1 nmol/L, 96.1 ± 11.6 nmol/L and 93.3 ± 7.6 nmol/L, P = NS). Measurement of MDA had good repeatability in both sputum and EBC, but the between-day variability was considerably higher in EBC. Sputum induction did not influence MDA levels. CONCLUSIONS: MDA in sputum, but not in EBC, appears to be a useful marker for monitoring exacerbation-associated oxidative stress in AECOPD.

Changes in synaptic efficacy in rat brain slices following extremely low-frequency magnetic field exposure at embryonic and early postnatal age.

An earlier study demonstrated changes in synaptic efficacy and seizure susceptibility in adult rat brain slices following extremely low-frequency magnetic field (ELF-MF) exposure. The developing embryonic and early postnatal brain may be even more sensitive to MF exposure. The aim of the present study was to determine the effects of a long-term ELF-MF (0.5 and 3 mT, 50 Hz) exposure on synaptic functions in the developing brain. Rats were treated with chronic exposure to MF during two critical periods of brain development, i.e. in utero during the second gestation week or as newborns for 7 days starting 3 days after birth, respectively. Excitability and plasticity of neocortical and hippocampal areas were tested on brain slices by analyzing extracellular evoked field potentials. We demonstrated that the basic excitability of hippocampal slices (measured as amplitude of population spikes) was increased by both types of treatment (fetal 0.5 mT, newborn 3 mT). Neocortical slices seemed to be responsive mostly to the newborn treatment, the amplitude of excitatory postsynaptic potentials was increased. Fetal ELF-MF exposure significantly inhibited the paired-pulse depression (PPD) and there was a significant decrease in the efficacy of LTP (long-term potentiation induction) in neocortex, but not in hippocampus. On the other hand, neonatal treatment had no significant effect on plasticity phenomena. Results demonstrated that ELF-MF has significant effects on basic neuronal functions and synaptic plasticity in brain slice preparations originating from rats exposed either in fetal or in newborn period.

Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) and electrosensibility (ES) - are they connected?

INTRODUCTION: The tendency of experiencing unpleasant symptoms in the proximity of working electric devices is called idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF). Evidence about psychophysiological backgrounds of the phenomenon (i.e., detection ability and mechanisms of symptom generation) is not yet conclusive. METHODS: Participants of the provocation experiment were 29 individuals with self-reported IEI-EMF and 42 control persons. Participants completed questionnaires (symptom expectations, somatosensory amplification - SSAS, modern health worries radiation subscale - MHW-R), and attempted to detect the presence of 50 Hz 0.5 mT magnetic field (MF) directed to their right arm in 20 subsequent 1-min sessions. Heart rate was also recorded and various indices of heart rate variability (HF, LF/HF, SDNN) were calculated. RESULTS: Using the methodology of the signal detection theory, individuals with IEI-EMF as opposed to the control group showed a higher than random detection performance (d' differed slightly but statistically significantly from zero), and they used a significantly lower criterion (ß value) when deciding about the presence of the MF. Detection sessions followed by correct decisions (hits or correct rejections) were characterized by higher HRV (SDNN and HF indices) than periods followed by errors (misses or false alarms). Previous expectations and affiliation to the IEI-EMF group were significant predictors of symptoms reported following exposure. IEI-EMF was closely related to MHW-R and SSAS scores. CONCLUSION: Detection of MF might be possible for people with IEI-EMF to some extent. Although heightened sensibility to MFs may play a role in the development and/or in the perpetuance of the IEI-EMF phenomenon, symptoms attributed to the MF seem to be mainly of psychogenic origin.