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Introduction: The diagnosis and severity assessment of COPD relies on spirometry, and in particular the FEV1. However, it has been proposed that hyperinflation and air-trapping are better predictors of exercise capacity and mortality than the FEV1. Research: question: Does static hyperinflation predict exercise capacity? Methods: We conducted an observational prospective study. Patients with COPD referred to the lung function laboratory were consecutively recruited. Patients with hyperinflation (the experimental group) were compared to patients without hyperinflation (the control group). The sample sizes were determined assuming an effect size of 0.5 and a power of 0.80. Results: We recruited 124 participants, of whom 87% were male, the mean age was 66.1 ± 8.8 years. 67% were symptomatic (GOLD B or D). Airflow limitation was moderate to severe in the majority of patients (median FEV1 47%, IQR 38-65%) and 43% of patients had static hyperinflation. The median 6MWD was 479 meters (404-510) and peak workload in CPET was 64 watts (46-88) with peak VO2 1.12 L/min, 0.89-1.31 L/min. Patients with lower FEV1, DLCO and IC/TLC and higher RV/TLC had reduced exercise capacity in both 6MWT and CPET, measured as lower distance, greater desaturation and ∆Borg dyspnoea, and reduced workload, peak VO2 and peak VE and higher desaturation and ventilatory limitation (VE/MVV). An IC/TLC < 0.33 predicted reduced exercise performance (peak O2

Communication between developing progenitor cells as well as differentiated neurons and glial cells in the nervous system is made through direct cell contacts and chemical signaling mediated by different molecules. Several of these substances are synthesized and released by developing cells and play roles since early stages of Central Nervous System development. The chicken retina is a very suitable model for neurochemical studies, including the study of regulation of signaling pathways during development. Among advantages of the model are its very well-known histogenesis, the presence of most neurotransmitter systems found in the brain and the possibility to make cultures of neurons and/or glial cells where many neurochemical functions develop in a similar way than in the intact embryonic tissue. In the chicken retina, some neurotransmitters or neuromodulators as dopamine, adenosine, and others are coupled to cyclic AMP production or adenylyl cyclase inhibition since early stages of development. Other substances as vitamin C and nitric oxide are linked to the major neurotransmitter glutamate and AKT metabolism. All these different systems regulate signaling pathways, including PKA, PKG, SRC, AKT and ERK, and the activation of the transcription factor CREB. Dopamine and adenosine stimulate cAMP accumulation in the chick embryo retina through activation of D1 and A2a receptors, respectively, but the onset of dopamine stimulation is much earlier than that of adenosine. However, adenosine can inhibit adenylyl cyclase and modulate dopamine-dependent cAMP increase since early developmental stages through A1 receptors. Dopamine stimulates different PKA as well as EPAC downstream pathways both in intact tissue and in culture as the CSK-SRC pathway modulating glutamate NMDA receptors as well as vitamin C release and CREB phosphorylation. By the other hand, glutamate modulates nitric oxide production and AKT activation in cultured retinal cells and this pathway controls neuronal survival in retina. Glutamate and adenosine stimulate the release of vitamin C and this vitamin regulates the transport of glutamate, activation of NMDA receptors and AKT phosphorylation in cultured retinal cells. In the present review we will focus on these reciprocal interactions between neurotransmitters or neuromodulators and different signaling pathways during retinal development.

Introduction: Height is one of the variables used to derive reference values for respiratory function but it is not always available. To fulfil this need, different formulas are described in literature. Aim: To understand which method best estimate height in order to obtain Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1st second (FEV1) reference values. Methods: The true stature (TS) and five alternative anthropometric measures that estimate height [arm span using a regression equation (ASR), arm span using a fix correction factor (ASF), half arm span, knee height and ulnar length] were measured for all patients. To assess the differences between the TS versus the estimated heights and the respective reference values of FVC and FEV1, T Student Test and Wilcoxon test were used. Agreement was evaluated by Intraclass Correlation Coefficient and by Bland-Altman plot. Results: A total of 160 subjects were recruited but 14 patients were excluded due to skeletal deformities. The predicted FVC and FEV1 using all alternative anthropometric measures were statistically different from those calculated by TS, except for ASF. The limits of agreement were wide for all alternative measures. With the exception of ASF, predicted FVC and FEV1 were overestimated when using all other alternative measures. Conclusions: For the purpose of replacing height in order to obtain predicted values of FVC and FEV1, the ASF was shown to be the most accurate and recommendable method. However, we must be aware there is a possible degree of error.

Introduction: Six-minute walk test (6MWT) is used for evaluating functional exercise capacity. To the best of our knowledge, there are no reference equations to predict six-minute walk distance (6MWD) for the Portuguese population. The aims of the present study were to measure anthropometric data and 6MWD in a sample of healthy Portuguese population, to establish reference equations to predict 6MWD and to compare our equations with those obtained by previously published studies. Methods: We conducted an observational prospective study. We consecutively recruited 158 healthy 18–70 years old subjects from Porto district, who performed two 6MWTs using a standardized protocol. The best 6MWD was used for further analysis. Results: The mean 6MWD was 627.8 m (SD = 73.3 m). The variables that were significantly associated with the 6MWD were age, sex, BMI and ΔHR (Heart Rateat the end of the test − HRat rest). We found three explanatory models for 6MWD, the best with an explanatory power of 38%: 6MWD = 721.7 − 1.6 × Age − 4.0 × BMI + 0.9 × ΔHR + 58.4 × Sex. We verified that 6MWD decreased 1.6 m per year of age, and 4.0 m per unit of BMI and increased 0.892 m per beat per minute. Moreover, on average, males walk 58.4 m more than females (p

Introduction and objectives: Tracheal stenosis is a rare and challenging disease. Bronchoscopy is the gold standard for diagnosis and assessment but brings inherent risks. Spirometry is commonly used to access obstructions but is not always feasible due to patient related factors. We therefore considered impulse oscillometry (IOS) as a non-invasive method to quantify airway obstruction and its potential use for diagnosis and follow-up of tracheal stenosis. Materials and methods: Patients with confirmed tracheal stenosis were recruited between January 1st, 2015 and December 31st, 2016. Before bronchoscopy, all subjects underwent IOS and spirometry; for patients submitted to interventional bronchoscopy the same techniques were also performed after the procedure. We assessed the correlation between IOS measurements and airway narrowing as well as between IOS and spirometry values. Results: Twenty-one patients were included. Tracheal narrowing was inversely correlated with X5% (r −0.442, p 0.045) and positively correlated with FEV1/PEF (r 0.467, p 0.033). The stenosis length was inversely correlated with PEF and PEF% (r −0.729, p = 0.001 and r −0.707, p = 0.002, respectively). There was a strong correlation between spirometric and IOS values. We did not find any significant differences between pre- and post-intervention IOS values for patients assessed after interventional bronchoscopy. Conclusions: Our study showed a weak correlation between X5% and tracheal narrowing making it unclear whether IOS can be used for physiological assessment of patients with tracheal stenosis. Stenosis length correlated with PEF making it a potential predictor of successful surgical approach. The correlation between IOS and spirometric values makes IOS a potential alternative in patients with suspected tracheal stenosis who are not able to perform spirometry. Larger scale studies should clarify the role of IOS in this pathology. Keywords: Impulse oscillometry, Spirometry, Bronchoscopy, Tracheal stenosis

Chronic Obstructive Pulmonary Disease (COPD) exacerbations play a central role in the disease natural history of the disease, affecting its overall severity, decreasing pulmonary function, worsening underlying co-morbidities, impairing quality of life (QoL) and leading to severe morbidity and mortality. Therefore, identification and correct assessment of COPD exacerbations is paramount, given it will strongly influence therapy success. For the identification of exacerbations, several questionnaires exist, with varying degrees of complexity. However, most questionnaires remain of limited clinical utility, and symptom scales seem to be more useful in clinical practice. In the assessment of exacerbations, the type and degree of severity should be ascertained in order to define the management setting and optimize treatment options. Still, a consensual and universal classification system to assess the severity and type of an exacerbation is lacking, and there are no established criteria for less severely ill patients not requiring hospital assessment. This might lead to under-reporting of minor to moderate exacerbations, which has an impact on patients’ health status.There is a clear unmet need to develop clinically useful questionnaires and a comprehensive system to evaluate the severity of exacerbations that can be used in all settings, from primary health care to general hospitals. Keywords: COPD, Assessment, Severity, Questionnaire, Exacerbations

Introduction: Erectile dysfunction (ED) is the inability to achieve or maintain an erection for satisfactory sexual activity. Recent studies have shown an association between ED and chronic obstructive pulmonary disease (COPD). However, this issue is often ignored. We aimed to evaluate the ED prevalence in COPD patients and its risk factors and to study the impact of dyspnea in sexual activity. Methods: Cross-sectional study that included sexually active male patients with COPD. The International Index of Erectile Function (IIEF-5) questionnaire evaluated ED and the Respiratory Experiences with Sexuality Profile (RESP) was used to evaluate the impact of dyspnea on sexual activity. Risk factors for mild-moderate or moderate ED were determined using logistic regression. Results: 84 patients were consecutively assessed for eligibility, 67 were included (median age: 65 years, 13% never-smokers). Twenty two percent had COPD 2011-GOLD A; 22% GOLD B, 14% GOLD C and 42% GOLD D. Fifty-eight patients (87%) had some degree of ED: 26 (45%) mild, 20 (34%) mild-moderate and 12 (21%) moderate ED. ED occurred in all GOLD stages of COPD, mainly in GOLD B and D stages. Higher CAT score was independently associated to mild-moderate/moderate ED. Most patients (85%) reported dyspnea during their sexual activity but 72% had never talked about it with their physician. Conclusions: ED is highly prevalent among COPD patients and it is more severe in patients with higher CAT scores. Dyspnea affects their sexual activity but this is not a topic often discussed between patients and doctors, something which needs to be improved. Keywords: Chronic obstructive pulmonary disease, Erectile dysfunction, Sexual activity

Vocal cord dysfunction (VCD) is a disorder characterized by unintentional paradoxical adduction of the vocal cords, resulting in episodic shortness of breath, wheezing and stridor. Due to its clinical presentation, this entity is frequently mistaken for asthma. The diagnosis of VCD is made by direct observation of the upper airway by rhinolaryngoscopy, but due to the variable nature of this disorder the diagnosis can sometimes be challenging. We report the case of a 41-year old female referred to our Allergology clinics with the diagnosis of asthma. Thorough investigation revealed VCD as the cause of symptoms.