Publications

We investigated whether stimulation of vagal afferent nerve fibers with inhaled capsaicin could induce a nonadrenergic inhibitory reflex in nine mild asthmatic subjects. Changes in total respiratory resistance (Rrs) were measured with a forced oscillation technique. First we induced a rise of 71 +/- 15% in Rrs (P less than 0.001) after leukotriene D4 aerosol. Subsequent inhalation of capsaicin (2 nmol) caused no significant change in mean Rrs of -1.1 +/- 8.2%. After the muscarinic receptor antagonist ipratropium bromide (120 micrograms) was inhaled, leukotriene D4 increased Rrs by 103 +/- 9% (P less than 0.001). Capsaicin subsequently caused bronchodilation in all subjects (Rrs = -22.3 +/- 2.7%, P less than 0.001). Ethanol-saline (diluent) alone caused a nonsignificant fall in Rrs (-9.9 +/- 4.7%) but a deep breath and coughing resulted in bronchodilation (-16.9 +/- 6.1%, P less than 0.05 and -11.6 +/- 2.9%, P less than 0.01, respectively). As observed in normal subjects, capsaicin may initiate an inhibitory reflex, presumably of nonadrenergic origin. This reflex could not be distinguished from that caused by coughing or by deep inhalation. A defect in nonadrenergic mechanisms, at least in mild asthma, seems unlikely.

Accumulation of nitrated protein is seen in peripheral lung and cells from patients with chronic obstructive pulmonary disease (COPD). Nitrated protein causes abnormal protein function, but the nitration was believed to be an irreversible process. However, there are accumulating evidences that this process is reversible by an active denitration pathway. The aim of this study is to detect denitration activity in protein extracts from peripheral lung tissue of COPD and to compare with those in healthy subjects.Peripheral lung tissue from 4 healthy, 4 smokers without COPD, 4 GOLD stage 1 and 4 GOLD stage 2 were used for denitration assay. Denitration activity was determined as reduction of nitro-tyrosine level of nitrated histone protein after incubation with protein extracts from peripheral lung, which was determined by western blotting. In addition, RNA is extracted from peripheral lung of 8 healthy, 7 smoking control, 8 stage 1 and 2 COPD and 10 stage 3 and 4 COPD and nitrate reductase mRNA expression was determined by real time RT-PCR.Peripheral lung protein extracts from healthy subjects reduced nitro-tyrosine level of nitrated histone. Thus, we were able to show denitration activity in peripheral lungs. The denitration activity was slightly reduced in smoking controls, and significantly reduced in COPD patients. We also showed that the expression of the human homologue of nitrate reductase (chytochrome β2 reductase), a potential candidate of denitrase, was significanty reduced in COPD lung.This study suggests that accumulation of nitrated protein in lung tissue of COPD may, at least in part, be induced by a reduction in denitration activity or nitrate reductase.

Wall shear stress (WSS) estimated in models reconstructed from intravascular imaging and 3-dimensional-quantitative coronary angiography (3D-QCA) data provides important prognostic information and enables identification of high-risk lesions. However, these analyses are time-consuming and require expertise, limiting WSS adoption in clinical practice. Recently, a novel software has been developed for real-time computation of time-averaged WSS (TAWSS) and multidirectional WSS distribution. This study aims to examine its inter-corelab reproducibility. Sixty lesions (20 coronary bifurcations) with a borderline negative fractional flow reserve were processed using the CAAS Workstation WSS prototype to estimate WSS and multi-directional WSS values. Analysis was performed by two corelabs and their estimations for the WSS in 3 mm segments across each reconstructed vessel was extracted and compared. In total 700 segments (256 located in bifurcated vessels) were included in the analysis. A high intra-class correlation was noted for all the 3D-QCA and TAWSS metrics between the estimations of the two corelabs irrespective of the presence (range: 0.90-0.92) or absence (range: 0.89-0.90) of a coronary bifurcation, while the ICC was good-moderate for the multidirectional WSS (range: 0.72-0.86). Lesion level analysis demonstrated a high agreement of the two corelabls for detecting lesions exposed to an unfavourable haemodynamic environment (WSS > 8.24 Pa, κ = 0.77) that had a high-risk morphology (area stenosis > 61.3%, κ = 0.71) and were prone to progress and cause events. The CAAS Workstation WSS enables reproducible 3D-QCA reconstruction and computation of WSS metrics. Further research is needed to explore its value in detecting high-risk lesions.

Eosinophils (EOS) may play an important role in the pathophysiology of bronchial asthma because they can release oxygen free radicals and several basic proteins which are cytotoxic to bronchial epithelium. We have studied the response of EOS isolated from the blood of atopic subjects with symptoms of asthma (AS, n = 7) or rhinitis (AR, n = 4) or without symptoms (AA, n = 5) and of subjects with the hypereosinophilic syndrome (HES, n = 5). EOS were separated using metrizamide density gradients and activated in vitro with platelet-activating factor (PAF, 100 nM) or phorbol 12-myristate-13-acetate (PMA, 100 nM). Oxygen free radical generation was assessed by a lucigenin-enhanced chemiluminescence (CL) assay. EOS purity was 83 +/- 1.7% (mean +/- SEM) with greater than 95% viability. Background CL responses of EOS from HES were significantly higher than those from AA (p less than 0.01) and AR (p less than 0.05). Normodense EOS from AS (PAF-induced CL = 90 +/- 27 mV) were more responsive to PAF than were those from AR (17 +/- 13 mV, p less than 0.01) and from AA (23 +/- 14 mV, p less than 0.01). Similar results were obtained with PMA. Hypodense EOS from HES subjects were as responsive as normodense EOS from AS to PMA and PFA. Thus, EOS from AS have an enhanced potential for activation, particularly by PAF; this may represent an important mechanism for the perpetuation of the inflammatory response in asthma, since EOS can also release PAF.

We have recently reported that protein phosphate 2A (PP2A) inactivation resulted in increased phosphorylation of the mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase 1 (JNK1) and glucocorticoid receptors (GR) at Ser226, thereby reducing GR nuclear translocation and causing corticosteroid insensitivity in severe asthmatics. Protein tyrosine phosphatases (PTPs) are also known to be critically involved in the regulation of MAPKs, such as JNK and therefore potentially associated with GR function. The aim of study was to elucidate the involvement of MAPK-PTPs (PTP-RR, PTP-N5 and PTP-N7), which can dephosphorylate MAPKs, in the regulation of corticosteroid sensitivity. Corticosteroid sensitivity, GR nuclear translocation, phosphorylation levels of GR-Ser226, JNK1 and PP2A catalytic subunit (PP2AC)-Tyr307 and protein expression levels and activities of PTP-RR and PP2AC were evaluated in U937 cells and/or peripheral blood mononuclear cells (PBMCs). Knock-down effects of MAPK-PTPs using siRNA were also evaluated. Knock-down of PTP-RR, but not of PTP-N5 or PTP-N7 impaired corticosteroid sensitivity, induced GR-Ser226 phosphorylation and reduced GR nuclear translocation. Under IL-2/IL-4-induced corticosteroid insensitivity, PTP-RR expression, activity and associations with JNK1 and GR were reduced but PTP-RR activity was restored by formoterol. Also in PBMCs from severe asthmatic patients, PTP-RR and JNK1 expression were reduced and GR-Ser226 phosphorylation increased. Furthermore, PTP-RR was associated with PP2A. PTP-RR reduction enhanced PP2AC-Tyr307 phosphorylation leading to impairment of PP2A expression and activity. We demonstrated that with corticosteroid insensitivity PTP-RR fails to reduce phosphorylation of JNK1 and GR-Ser226, resulting in down-regulation of GR nuclear translocation. Reduced PTP-RR may represent a novel cause of corticosteroid insensitivity in severe asthmatics.

No abstract is provided for this article.

BACKGROUND: Analysis of bronchoalveolar lavage fluid has improved our understanding of the pathogenesis of asthma. Safety issues and access to expert resources limit this techniques as a research tool. Induced sputum is a non-invasive method of collecting airway fluid which is applicable to subjects with a range of severity of airflow obstruction. The method of sputum collection and processing differs between groups. A study was undertaken to compare induced sputum with bronchoscopically collected fluid. METHODS: Sixteen patients with mild stable asthma underwent both sputum induction and bronchoscopic examination with bronchial washings and bronchoalveolar lavage (BAL) in random order, with each procedure being separated by an interval of 12 days. Airway fluid was processed and stained for differential cell counting. RESULTS: Induced sputum was relatively rich in neutrophils and eosinophils compared with bronchial washings and BAL fluid (mean (SE) 1.3 (0.4)%, 5.0 (2.7)%, and 36.4 (3.7)% neutrophils and 0.6 (0.1)%, 1.6 (0.6)%, and 3.3 (1.1)% eosinophils in BAL fluid, bronchial washings, and induced sputum, respectively). The proportions of cells obtained at sputum induction correlated with those in bronchial washings but not BAL fluid (r = 0.6 and 0.7 for neutrophils and eosinophils, respectively, p < 0.05). By contrast, induced sputum had a lower proportion of lymphocytes and macrophages than bronchial washings or BAL fluid, without any correlation. CONCLUSION: Induced sputum is rich in neutrophils and eosinophils and poor in lymphocytes, suggesting an origin in the larger airways. Induced sputum adequately reflects the findings in fluid collected by direct bronchoscopy.

Diabetes mellitus and angiographic coronary artery disease complexity are intertwined and unfavorably affect prognosis after percutaneous coronary interventions, but their relative impact on long-term outcomes after percutaneous coronary intervention with drug-eluting stents remains controversial. This study determined drug-eluting stents outcomes in relation to diabetic status and coronary artery disease complexity as assessed by the Synergy Between PCI With Taxus and Cardiac Surgery (SYNTAX) score.In a patient-level pooled analysis from 4 all-comers trials, 6081 patients were stratified according to diabetic status and according to the median SYNTAX score ≤11 or >11. The primary end point was major adverse cardiac events, a composite of cardiac death, myocardial infarction, and clinically indicated target lesion revascularization within 2 years. Diabetes mellitus was present in 1310 patients (22%), and new-generation drug-eluting stents were used in 4554 patients (75%). Major adverse cardiac events occurred in 173 diabetics (14.5%) and 436 nondiabetic patients (9.9%; P<0.001). In adjusted Cox regression analyses, SYNTAX score and diabetes mellitus were both associated with the primary end point (P<0.001 and P=0.028, respectively; P for interaction, 0.07). In multivariable analyses, diabetic versus nondiabetic patients had higher risks of major adverse cardiac events (hazard ratio, 1.25; 95% confidence interval, 1.03-1.53; P=0.026) and target lesion revascularization (hazard ratio, 1.54; 95% confidence interval, 1.18-2.01; P=0.002) but similar risks of cardiac death (hazard ratio, 1.41; 95% confidence interval, 0.96-2.07; P=0.08) and myocardial infarction (hazard ratio, 0.89; 95% confidence interval, 0.64-1.22; P=0.45), without significant interaction with SYNTAX score ≤11 or >11 for any of the end points.In this population treated with predominantly new-generation drug-eluting stents, diabetic patients were at increased risk for repeat target-lesion revascularization consistently across the spectrum of disease complexity. The SYNTAX score was an independent predictor of 2-year outcomes but did not modify the respective effect of diabetes mellitus.URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00297661, NCT00389220, NCT00617084, and NCT01443104.

Bronchiectasis is characterized by chronic inflammation in one or more bronchi, but the extent of inflammation is difficult to monitor. The concentration of nitric oxide (NO) in exhaled air is increased in asthmatic patients, possibly as a result of the chronic inflammatory process. We have measured exhaled NO in patients with documented bronchiectasis and investigated whether the concentration of exhaled NO is related to the extent of disease as defined by computed tomography (CT) and lung function. In 20 patients with bronchiectasis who were not taking inhaled steroids, the peak concentration of NO in exhaled air, measured by a modified chemiluminescence analyzer, was significantly elevated (285 +/- 49.0 ppb) as compared with values for 79 normal subjects (89 +/- 2.7 ppb, p < 0.01) and 19 patients with bronchiectasis treated with inhaled steroids (88 +/- 13.4 ppb, p < 0.01). Thin-section CT was used to quantify the extent of bronchiectasis in the 19 patients. There was a significant correlation between the CT score and FEV1 (r = 0.73, p < 0.01). In patients not treated with inhaled steroids there was a significant relationship between CT score and peak exhaled NO (r = 0.81, n = 12, p < 0.02), but this was not the case for patients treated with regular inhaled steroids (n = 7). We conclude that untreated bronchiectasis is associated with an increase in exhaled NO, and that this is correlated with disease severity, whereas patients treated with inhaled steroids have levels of exhaled NO within the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

This in vitro study was designed to assess the contribution of three currently investigated coronary stents to the densitometrlc measurement of a known stenosis contained within two different sized plexiglass phantoms. These studies were performed at two concentrations of the contrast agent iopamidol (50 and 100%). The calculated minimal luminal cross‐sectional area values in the control phanton ranged from 0–18% higher than the theoretical values. Insertion of a stainless steel stent (Wallstent™, Schneider, Zürich or Palmaz‐Schatz™, Johnson and Johnson, Warren, NJ) resulted in further minor increases (≤8%) in the calculated minimal luminal cross‐sectional area, except in the smaller phantom filled with 50% contrast medium. The Wiktor™ (tantalum) stent (Medtronic, Minneapolis, MN) had the largest impact of the three stents depending on the concentration of iopamidol (100% contrast medium: 9–13% values above control; 50% contrast medium; 23–56% higher). We conclude that although densitometry may overestimate the minimal luminal cross‐sectional area in stented vessels, this effect is usually minor with stainless steel stents. However, tantalum‐containing stents may result in serious overestimation of lesion area, particularly if contrast is diluted or the vessel Is not well filled.