Cartas al editor / Revisión por pares

A asma é uma doença inflamatória crônica das vias aéreas responsável por considerável morbimortalidade em todo o mundo. O tratamento atualmente disponível que inclui broncodilatadores e corticosteróides, apresenta respostas variáveis e alguns pacientes não atingem o controle preconizado. Além disso, esses medicamentos apresentam efeitos colaterais indesejáveis. Assim, é necessário o desenvolvimento de novas drogas para o tratamento da asma. A Pyrostegi venusta (KerGahl.) Miers (\"cipó-de-são-joão\", Bignoniaceae), uma trepadeira amplamente distribuída no mundo inteiro e no Brasil principalmente no cerrado brasileiro, apresenta atividade anti-inflamatória e antioxidativa. Até o momento, não há descrição de estudos de P. venusta no tratamento da asma. O objetivo do estudo foi avaliar os efeitos da administração de dois extratos de P. venusta nas doses de 100 e 300mg/kg no tratamento da asma em um modelo animal e os mecanismos envolvidos. Foram realizados dois protocolos com períodos de tratamento e doses diferentes. No protocolo 1, camundongos Balb/c foram sensibilizados duas vezes com ovalbumina (OVA) intraperitoneal (ip), com uma semana cada de intervalo; após uma semana, foram desafiados com OVA intranasal (in) por três dias consecutivos, os camundongos receberam tratamento com extrato aquoso ou extrato hidroetanólico de P. venusta (100 mg/kg) por via ip, também por três dias consecutivos, durante os desafios com OVA. No protocolo 2, camundongos Balb/c foram sensibilizados duas vezes com OVA ip, com uma semana de intervalo e, após uma semana, desafiados com OVA in por quatro dias alternados. Os animais foram tratados com os extratos aquoso ou extrato hidroetanólico de P. venusta (300 mg/kg), ip, por sete dias consecutivos. Camundongos controles receberam salina nos mesmos dias. Após a sensibilização e desafios, os animais foram ventilados e foram realizadas medidas in vivo da hiper-responsividade brônquica com concentrações crescentes de metacolina. Após, foi coletado lavado broncoalveolar para contagem total e diferencial de células. O sangue foi coletado para dosagem de IgE específica para OVA e os pulmões foram retirados para dosagem de citocinas e capacidade antioxidante no homogenato pulmonar e análise histológica. No protocolo 1, houve redução de células totais, eosinófilos e da hiper- responsividade brônquica no grupo tratado com extrato aquoso quando comparado ao grupo controle. O extrato hidroetanólico não reduziu a inflamação das vias aéreas. Em relação ao protocolo 2, o grupo asmático que recebeu tratamento com extrato aquoso apresentou diminuição de células inflamatórias totais, eosinofílicas e no tecido pulmonar, além de diminuição da hiper-responsividade brônquica e aumento da capacidade antioxidante. O grupo tratado com extrato hidroetanólico apresentou redução apenas de células totais e de eosinófilos. Os extratos aquoso e hidroetanólico da P. venusta não reduziram os níveis de citocinas inflamatórias. Conclui-se que a administração do extrato aquoso de P. venusta na dose de 300mg/kg atenuou as principais características da asma em um modelo animal, provavelmente por um mecanismo antioxidante. / Asthma is a chronic inflammatory disease of the airways responsible for considerable morbidity and mortality worldwide. With the currently available treatment, including bronchodilators and corticosteroids, some patients do not reach the recommended control. Furthermore, these drugs have undesirable side effects. Thus, the development of new drugs for the treatment of asthma is needed. P. venusta (KerGahl.) Miers (\"liana-of St. John,\" Bignoniaceae), a widely distributed climbing worldwide and in Brazil mainly in the Brazilian cerrado, has anti-inflammatory and antioxidative activity. To date, there is no study of P. venusta in the treatment of asthma. The aim of the study was to evaluate the effects of administration of two extracts of P. venusta with different doses (100 and 300 mg/kg) in the treatment of asthma in an animal model and the mechanisms involved. Two protocols were conducted with different period of treatment. In protocol 1, Balb/c mice were sensitized twice with ovalbumin (OVA) intraperitoneally (ip) one week apart. After one week, mice were challenged with intranasal OVA for three consecutive days and treated with aqueous extract or hydroethanolic extract of P. venusta (100mg/kg) ip for three consecutive days, during OVA challenges. In protocol 2, Balb/c mice were sensitized ip with OVA twice with an interval of one week and after one week challenged four times with OVA intranasally in alternate days. The animals were treated with the aqueous extract or hydroethanolic extract of P. venusta (300 mg/kg) ip for seven consecutive days. Control mice received saline on the same days. After sensitization and challenge, the animals were ventilated and in vivo measurement of bronchial hyperresponsiveness was performed wiht increasing concentrations of methacholine. After, bronchoalveolar lavage was collected for total and differential cell count. The blood was collected to measure OVA specific IgE and lungs were removed for cytokines quantification in the pulmonary homogenates and histological analysis. In protocol 1, aqueous extract administration significantly reduced total and differential cells number, and bronchial hyperresponsiveness compared to the group that received no treatment. Hydroethanolic extract did not significant reduce airway inflammation. In relation to Protocol 2, the asthmatic group treated with aqueous extract had a significant decrease in total and differential inflammatory cells, lung inflammation, and bronchial hyperresponsiveness. Moreover, aqueous extract administration increased significantly antioxidant capacity. The hydroethanol extract decreased significantly only total cells and eosinophils. The aqueous and hydroethanolic extracts of P. venusta did not reduce the levels of inflammatory cytokines. We conclude that the administration P. venusta aqueous extract at a dose of 300mg/kg attenuated the main features of asthma in an animal model, probably via an antioxidant mechanism.

During embryogenesis, airway epithelial cells possess primary cilia, and HH signaling guides lung development. As epithelial cells mature, they produce hundreds of motile cilia and continue to produce the sonic hedgehog (SHH) ligand, which is found apically in the thin layer of liquid covering airways. However, whether ciliated airway cells express apical HH signaling components and what their function might be have remained unknown. Here we show that motile cilia are enriched for HH signaling proteins, including patched 1 and smoothened. These cilia are also enriched for proteins affecting cAMP-dependent signaling, including Gαi and adenylyl cyclase 5/6. Surprisingly, SHH in differentiated airway epithelia did not elicit the canonical SHH signaling pathway that regulates transcription during development. But instead, activating HH signaling decreases intracellular levels of cAMP, which reduces ciliary beat frequency and airway surface liquid pH, similar to changes that have been observed in the airway of people with chronic obstructive pulmonary disease (COPD). Furthermore, we observed that significant increase of SHH ligand expression in differentiated airway epithelia with COPD, suggesting a potential role of SHH signaling in the pathogenesis of airway disease. Collectively, our study indicates that airway cilia detect apical SHH to mediate airway physiology through noncanonical HH signaling. SHH may dampen defenses at the contact point between the environment and the lung, perhaps counterbalancing processes that stimulate airway defenses. This may suggest a potential role of SHH signaling in the pathogenesis of airway disease, such as COPD.

acase@tulane.edu

Cystic fibrosis (CF) is a lethal genetic disease that affects 30,000 people in the United States alone. While the disease affects organs throughout the body, it is the lung disease that is the primary cause of morbidity and mortality for people with the disease. CF lung disease is characterized by thick and sticky mucus that obstructs the airways, acute and chronic bacterial infections, and chronic inflammation and remodeling. Thanks to the creation of the CF pig, it is now possible to study the manifestations of CF lung disease at birth. The CF pig develops spontaneous lung disease, similar to that found in humans with CF, making it the ideal model for our studies. One of the critical findings that revealed in studies of the CF pig is that airway surface liquid (ASL) bactericidal activity is impaired in CF at birth, and this activity is pH dependent. Because infants and children with CF tend to suffer greater morbidity from respiratory viruses than non-CF infants and children, we sought to determine if ASL has antiviral activity and if that activity is reduced in newborn CF pigs. We found that pre-incubating either tracheal or nasal ASL from wild-type pigs reduced the infectivity of various recombinant viruses expressing an eGFP or GFP reporter gene. Those viruses include Sendai virus (SeV-eGFP), respiratory syncytial virus (RSV-GFP), the PR8 strain of influenza virus A (PR8-eGFP), and adenovirus (Ad-eGFP), indicating ASL has broad-spectrum antiviral activity. Nasal secretions from newborn CF pigs had strikingly reduced antiviral activity against SeV-eGFP and Ad-eGFP compared to nasal secretions from WT littermates. Unlike what was observed for ASL antibacterial activity, nasal secretion antiviral activity was not affected by pH, nor was it affected by bicarbonate concentration, one of the molecules that drives pH in the airways. However, when we mixed CF and WT nasal secretions at different ratios, we found the antiviral activity to follow a linear trend, with antiviral activity increasing as the percentage of WT nasal secretions increased. This suggests that one or more components of nasal secretions are found less abundantly in CF nasal secretions compared to WT nasal secretions, leading to reduced antiviral activity in CF. The CF pig has facilitated a much greater understanding of the early stages of CF lung disease. This model will allow us to determine what antiviral components are lacking in the CF airways and why they are reduced in CF.

Doctor of Philosophy (PhD) / It is well recognised that both genetic and environmental factors determine an individual’s predisposition to asthma. In recent years, the airway smooth muscle (ASM) cell has come to the attention of researchers to, not merely be a contractile cell of the airway, but one that orchestrates events affecting airway remodelling and proliferation. Experiments described in this thesis have, for the first time, examined genes that are associated with various aspects of the pathogenesis of asthma by using the candidate gene approach and a genome wide search. Genes have not only been identified to be differentially expressed in ASM cells derived from asthmatic and non-asthmatic participants, but have also been linked with a functional consequence of asthma. The three genes found to be differentially regulated between ASM cells derived from asthmatic and non-asthmatic participants were Peroxisome Proliferator-Activated Receptor- gamma (PPARγ), mimecan and fibulin-1. Expression of the anti-proliferative transcriptional factor PPARγ, found by the candidate gene approach, was elevated in ASM cells derived from asthmatic participants. Whilst elevated, the anti-proliferative effect of PPARγ was absent in ASM cells derived from asthmatic participants. By microarray analysis, mimecan, an anti-proliferative agent was identified. Mimecan levels, although not different basally in ASM cells, were upregulated by transforming growth factor β (TGFβ) only in asthmatic derived ASM cells. Silencing mimecan, by the use of specific oligonucleotides, increased proliferation of ASM cells. This suggested that by increasing mimecan expression, the proliferation of ASM cells may be halted. Fibulin-1, also found by microarray analysis and the final gene examined in this thesis, was found in elevated levels in BAL fluid, serum and ASM cells obtained from asthmatic participants. In addition, ASM cells derived from asthmatic participants, for the first time were shown to have faster wound healing rates compared with nonasthmatics. The elevated fibulin-1 levels in ASM cells derived from asthmatic participants, in the presence of TGFβ, were demonstrated to contribute to this increased wound healing. Specifically, fibulin-1 was found to affect wound healing by increasing proliferation rather than migration. The current available treatments for asthma, target the contractility and inflammatory conditions in the airway. Through this thesis, novel genes discovered to be associated with proliferation may be potential therapeutic targets to treat asthma. In particular, the fibulin-1 gene is outstandingly promising, as it was shown that silencing fibulin-1 resulted in slower wound healing rates through decreased cell proliferation, to possibly inhibit the airway remodelling observed in asthma, and furthermore, corticosteroid therapy was demonstrated not to affect to this gene.

<p>The purpose of this study was to explore nurses' experiences of obstructed airways in the prehospital work.</p><p>A qualitative interview study with a descriptive and explorative design was used. The sample consisted of nine registered nurses whereof three were women and six were men, with or without further education and varying length of experience in the ambulance service.</p><p>Prehospital personnel builds up a vast plan of action based on the emergency information provided by SOS. Simple methods for managing obstructed airways were stated often enough. Problems with obstructed airways are considered so unusual that it never becomes a routine. Several factors affect the identification and managing of obstructed airways, both external factors and the different patient categories are considered important. The study found that the bystanders rarely perceived to be performing actions for the creation of a free airway. While obstructed airways perceived to be stressful for ambulance nurses, however, they are not worried to face such a situation. For the coping of what has happened during an emergency, ambulance crew talk through the whole situation of what could have been done better or if something could be done differently. Many factors affect the identification and managing of obstructed airways in prehospital nurses' work. While obstructed airways perceived to be stressful for ambulance nurses they are not concerned to face such a situation. The tools and techniques available for managing airways are usually considered to be adequate and well-functioning</p>

MUC4 is a heterodimeric mucin glycoprotein expressed in the epithelia of tissues. Previous studies in our laboratory demonstrated that MUC4 protein expression is regulated by exogenous growth factors and that MUC4 is found in complex with the receptor tyrosine kinase ErbB2. MUC4 protein expression in airway epithelia was evaluated using molecular biology techniques. The impact of the protein on ErbB2 activation was evaluated post mechanical wounding of airway epithelia, and upon MUC4 RNA silencing. MUC4 levels were increased with exposure to the differentiating agent retinoic acid and decreased upon exposure to epidermal growth factor, a proliferative agent. In the absence of MUC4, ErbB2 phosphorylation was diminished. These results support the hypothesis that MUC4 expression is enhanced during differentiation of epithelia. Furthermore these findings provide evidence for an additional level of ErbB regulation in airway injury and subsequent epithelial wound healing.

DOES INCREASING FLOW TO A HIGH FLOW NASAL CANNULA AFFECT MEAN AIRWAY PRESSURE IN AN IN VITRO MODEL? Introduction: High-flow nasal cannulas (HFNC) have become popular with many institutions for administration of oxygen (O2). HFNCs are also being used in pediatric and neonatal populations for administration of continuous positive airway pressure (CPAP) as a treatment for respiratory distress. Adult patients are being treated with HFNCs in a effort to provide a high percentage of O2 and correct hypoxemia and other related conditions. The purpose of this study was to examine the effect of increasing flow via a HFNC to an in vitro model to examine the effect of flow on mean airway pressure (MPAW). Method: An in vitro model to simulate non-labored and labored spontaneous breathing was developed using a Michigan Instrument Laboratory Test and Training Lung (MIL TTL) driven by a Hamilton Galileo ventilator to produce a negatively based, inspired tidal volume. Flow was introduced to the MIL TTL via a 41 French double lumen endotracheal tube. Airway pressure measurements were observed via a pressure monitoring port placed between the MIL TTL and the endotracheal tube and connected to the auxiliary pressure monitoring port located on the front of the Galileo ventilator. A Vapotherm 2000i with adult transfer chamber and adult cannula, a Fisher Paykel Optiflow, and a generic HFNC consisting of a concha column and a Salter labs high-flow cannula were tested at 20, 30, and 40LPM flowrates. Data was recorded using two respiratory rates (12 and 24) and two peak flowrates (35 and 65LPM) to simulate non-labored and labored breathing. All other parameters were unchanged and the I:E ratio was consistent. Data Analysis: SPSS 16.0 for Windows was used to analyze all data for this study. Descriptive statistics, one-way analysis of variance (ANOVA), and post hoc Bonferroni was used for this study. A p value less than 0.05 were considered significant. Results: Average MPAW for all devices were increased at all three flowrates. MPAW was highest at 40LPM flow producing 3.1cmH2O averaged for all HFNCs and both respiratory patterns. The difference in MPAW produced by the three HFNCs were also significant with at p=0.000 at all flow rates. Post hoc Bonferroni adjusted probabilities further showed all device comparisons significant except for Vapotherm-Vapotherm Labored at 30 and 40 LPM flow rates and Vapotherm-Generic Labored at 20 LPM at p<0.05. These three comparisons were at p>0.05 and were statistically equal. The generic HFNC produced the highest MPAW (3.5cmH2O). Conclusion: Increased flow via a HFNC does increase MPAW. The Vapotherm, Optiflow, and generic HFNC did not produce the same level of MPAW in this study.

Thesis (M.Sc.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Medical Sciences - Orthodontics. Title from pdf file main screen (viewed on November 29, 2009). Includes bibliographical references.