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Efeitos da desobstrução rinofaríngea retrógada isolada e associada à instilação de soro fisiológico (0,9%NACL), sobre as propriedades do muco nasal, a celularidade e as citocinas em lavado nasal e sintomas nasais de motociclistas profissionais expostos à poluição da cidade de Belo Horizonte / Effects of isolated clearance rhinopharyngeal retrograde and clearance rhinopharyngeal retrograde associated with the irrigation of isotonic saline solution (0.9% NaCl) on the nasal mucus properties, celularity, and in nasal lavage and the nasal symptoms in professional motorcyclists exposed to air pollutions in the city of Belo Horizonte, BrazilTereza Cristina Silva Brant 22 August 2014 (has links)
Introdução: A desobstrução rinofaríngea retrógrada (DRR) é uma técnica de fisioterapia respiratória aplicada em lactentes para desobstrução de vias aéreas superiores, podendo, inclusive, ser associada à irrigação nasal com salina isotônica para remoção de muco viscoso aderido às paredes das vias aéreas. Objetivo: Caracterizar o perfil de motociclistas profissionais expostos à poluição urbana no que se refere a transporte mucociliar nasal (TMCN), inflamação das vias aéreas superiores e sintomas nasais, e comparar o efeito da DRR isolada e associada à instilação de salina isotônica (DRR+S) nesta população. Métodos: Vinte e quatro voluntários divididos aleatoriamente em dois grupos (DRR e DRR+S) submeteram-se a 15 dias consecutivos de tratamento. A avaliação basal e a pós-intervenção constituíram-se da análise do teste de trânsito da sacarina, da celularidade total e diferencial do lavado nasal e dos sintomas de vias aéreas superiores por meio do questionário SNOT-20, bem como do estudo da exposição pessoal à poluição do ar, por meio da análise da concentração do NO2 de amostradores passivos. O TMCN foi avaliado pelo teste ANOVA não paramétrico com medidas repetidas e o SNOT-20 pelo teste Mann-Whitney. As correlações entre a concentração de NO2 e os desfechos das vias aéreas superiores foram testadas por meio do coeficiente de correlação de Spearman. Resultados: Os grupos apresentaram dados clínicos e demográficos semelhantes. O TMCN apresentou-se alterado em 25% dos voluntários e 100% deles apresentavam sintomas de vias aéreas superiores. Após os tratamentos, os sintomas de vias aéreas e o TMCN evidenciaram melhora significativa, apesar do aumento no número de macrófagos e células ciliadas do lavado nasal. Não houve correlação entre o NO2 e o TMCN, tampouco em relação aos sintomas de vias aéreas superiores. CONCLUSÃO: Técnicas não farmacológicas, simples e de baixo custo são efetivas para recuperar o TMCN alterado e melhorar os sintomas de vias aéreas superiores em adultos não tabagistas / Introduction: Rhinopharyngeal Retrograde Clearance (RRC) is a respiratory therapy technique applied to infants with upper airway obstruction that may also be associated with nasal irrigation with isotonic saline for removal of viscous mucus adhered to the walls of the airways. OBJECTIVE: Characterize the profile of professional motorcycles exposed to urban pollution in relation to the nasal mucociliary transport (NMCT), inflammation of the upper airways and nasal symptoms and compare the effect of DRR alone and associated with instillation of isotonic saline (RCC + S). Methods: Twenty-four volunteers were randomly divided into two groups (RCC and RCC + S) and were submitted to 15 consecutive days of treatment. The baseline and post-intervention consisted of analysis of the transit saccharin test, the total and differential cellularity nasal lavage, and symptoms of upper airway through the SNOT-20, as well as the study of personal exposure to air pollution, by analyzing the concentration of diffuse nitrogen dioxide monitoring system. The NMCT was evaluated with ANOVA for repeated measures and the SNOT-20 with the Mann-Whitney test. The correlations between the concentration of NO2 and the upper airway outcomes were tested using the Spearman correlation coefficient. Results: The groups showed similar demographic and clinical data. The NMCT was abnormal in 25% of the volunteers and 100% of the volunteers had symptoms of upper airways. After treatment the upper airway symptoms and the NMCT showed significant improvement despite the increase in the number of macrophages and ciliated cells on the nasal lavage. No correlation was observed between dioxide nitrogen and TMCN and with the symptoms of the upper airways. Conclusion: Nonpharmacological, simple and inexpensive techniques are effective to treat abnormal NMCT and improve symptoms of upper airway in nonsmoking adults
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Estudo de um modelo experimental para o desenvolvimento de enfisema pulmonar induzido por elastase e fumo em camundongos / An experimental model of elastase and cigarette smoke-induced emphysema in miceRubia Rodrigues 26 June 2015 (has links)
Os modelos experimentais têm sido utilizados para o estudo dos mecanismos fisiopatológicos envolvidos no desenvolvimento da Doença Pulmonar Obstrutiva Crônica (DPOC). O modelo que melhor mimetiza a doença em humanos é o que utiliza a exposição à fumaça de cigarro. No entanto, a utilização deste modelo experimental requer um longo tempo de exposição (6 meses) e a lesão do parênquima obtida é considerada leve. O desequilíbrio protease/anti-protease é considerado um importante mecanismo fisiopatológico envolvido no desenvolvimento da DPOC. Desta forma, neste estudo propomos o desenvolvimento de um modelo experimental no qual associamos a instilação de elastase previamente ao início da exposição ao fumo na tentativa de obter um maior grau de lesão tecidual em um menor espaço de tempo. Para tanto, camundongos C57Bl/6 foram divididos em quatro grupos: Controle, Elastase, Fumo, Fumo/Elastase 1 dose e Fumo/Elastase 2 doses e analisados após dois meses de exposição. Os animais do grupo Fumo/Elastase 1 dose e 2 doses foram submetidos à instilação intranasal de elastase pancreática de porco (0,33UI) e expostos a fumaça de cigarro por dois meses. O grupo controle recebeu o mesmo tratamento com solução fisiológica (NaCl 0.9%). A exposição ao fumo foi feita por 30min, 2 vezes/dia, 5 dias da semana. Após dois meses, os animais foram sacrificados e observamos aumento de LM no grupo Fumo/Elastase 1 dose e 2 doses comparado aos grupos Controle e Fumo; aumento de células positivas para MAC-2 no parênquima (Fumo/Elastase 2 doses) e vias aéreas (Fumo/Elastase 1 dose e 2 doses), MMP-12 no parênquima pulmonar (Fumo/Elastase 2 doses), GP91 no parênquima (Fumo/Elastase 1 dose e 2 doses) e vias aéreas (Fumo e Fumo/Elastase 1 dose) e aumento de proporção de fibras elásticas no parênquima pulmonar do grupo Fumo/Elastase 1 dose e do grupo Fumo, caracterizando presença de enfisema pulmonar. A instilação de elastase pancreática de porco juntamente com a exposição à fumaça de cigarro aumentou a susceptibilidade ao desenvolvimento do enfisema / Experimental models have been used to study the pathophysiological mechanisms involved in the development of COPD. Cigarette Smoke exposure (CS) is considered the best model to mimetize the disease in humans. However, the CS requires a long exposure time (6 months) and the parenchymal destruction obtained is considered mild. The protease / anti - protease imbalance is considered an important pathophysiological mechanism involved in the development of COPD. Thus, in this study we propose the development of an experimental model in which we associate instillation of elastase before the start of exposure to smoke, trying to increase the parenchymal destruction degree in a shorter time. For that, C57BL / 6 mice were divided into four groups: Control, Elastase, Smoke and Smoke/Elastase 1 dose and Smoke/Elastase 2 doses and analyzed in two months after the CS exposition. The Smoke/Elastase 1 dose and 2 doses animals group received an intranasal instillation of porcine pancreatic elastase (0.33 IU) and exposed to cigarette smoke for two months. The control group received the same treatment with saline (NaCl 0.9 %). Animals were exposed to CS for 30min, 2 times / day, 5 days a week. After two months, we observed increased mean linear intercept (LM) and positive cells for MAC-2, MMP-12 and GP91 in the airways and lung parenchyma and increase of elastic fibers in the lung parenchyma characterizing the presence of pulmonary emphysema. The instillation of porcine pancreatic elastase along the exposure to cigarette smoke increased susceptibility to the development of emphysema
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Avaliação dos efeitos pulmonares e sistêmicos agudos em resposta à injeção intrapleural de talco de diferentes tamanhos de partículas / Pulmonary and systemic response following intrapleural instillation of talc with different particle sizeViviane Rossi Figueiredo 16 January 2007 (has links)
Pacientes com comprometimento pleural por neoplasias malignas freqüentemente apresentam derrame pleural recidivante. Nestes casos, a sínfise das membranas pleurais (pleurodese) com a finalidade de evitar o acúmulo de líquido no espaço pleural deve ser considerada. O talco é o agente mais utilizado indicado para essa finalidade. Entretanto, seu uso terapêutico continua controverso devido aos efeitos deletérios que podem advir de sua utilização. O mais grave entre todos é a insuficiência respiratória aguda, que pode evoluir para a síndrome do desconforto respiratório agudo (SDRA). Essa complicação pode estar relacionada com a composição, com o tamanho das partículas de talco e com a resposta inflamatória desencadeada pelas mesmas. O objetivo deste estudo foi avaliar os efeitos pulmonares e sistêmicos em resposta à injeção intrapleural (IIP) de talco de partículas pequenas (TP) e de partículas de tamanhos diversos (TM). Cem coelhos foram submetidos à IIP com talco. Metade dos animais foi injetada com TP (diâmetro médio= 6,41 mm) e outra metade com TM (diâmetro médio= 21,15 mm), que é o talco usado na prática clínica. Quinze coelhos compuseram o grupo controle. Foram avaliados a celularidade, os níveis de desidrogenase lática (DHL), proteína C reativa (PCR), interleucina-8 (IL-8) e fator de crescimento endotelial vascular (VEGF) no sangue e no lavado broncoalveolar (LBA) às 6, 24, 48, 72 e 96 horas após a IIP. Realizou-se também a quantificação de partículas de talco e a análise histológica dos pulmões. Utilizamos o teste t e Anova na análise estatística, considerando p< 0,05 como significância estatística. A maioria dos parâmetros avaliados apresentou níveis mais elevados no sangue e no LBA dos animais injetados com TP ou TM quando comparados ao grupo controle, sugerindo uma resposta sistêmica e pulmonar à IIP de talco. Com relação aos grupos de talco, os níveis de PCR e de IL-8 apresentaram-se mais elevados no sangue e no LBA dos animais injetados com TP. Partículas de talco foram observadas em todas as lâminas examinadas, sem diferenças significativas entre os grupos. Os pulmões dos animais injetados com TP apresentaram infiltrado linfomononuclear mais exuberante que no grupo TM. A resposta inflamatória pulmonar antecedeu (24 h) a resposta sistêmica (48 h), sugerindo que o pulmão é o principal órgão da resposta sistêmica aguda. Estes achados estudo nos permitem concluir que o talco calibrado com partículas maiores deva ser utilizado na prática clínica, objetivando uma pleurodese mais segura. / Talc has been the pleurodesis agent of choice for the local treatment of recurrent pleural diseases. However, serious concerns exist about its safety. The acute respiratory failure is considered its most serious complication. The physiopathologic mechanisms involved are still unclear. It has been attributed to the systemic dissemination of small talc particles, to the composition of talc and to the inflammatory response. The purpose of this study was to evaluate the systemic and pulmonary response following intrapleural instillation of small particles talc (ST) and mixed particles talc (MT). One hundred rabbits received intrapleural instillation of talc as follows: fifty rabbits were instilled with ST (mean diameter=6,41 microns), and 50 rabbits with MT (mean diameter= 21,15 microns). As control (without talc instillation) were used 15 animals. We studied the pulmonary and systemic inflammatory response (total cell count and differential, levels of lactate dehydrogenase (LD), C-reactive protein (PCR), interleukin-8 (IL-8) and human vascular endothelial growth factor (VEGF) in serum and bronchoalveolar lavage (BAL). Histologic analysis of both lungs and quantitation of talc particles were done at 6, 24, 48, 72 and 96h. ST group showed higher pulmonary and systemic inflammatory response than did the MT group. PCR and IL-8 concentrations were higher in serum and BAL of ST group than the MT group. Many talc particles were observed in the pulmonary tissue of both talc groups, but without statistical significance. We also observed a predominance of cellular infiltrates (lymphomononuclear cells) in the lungs of ST group. The pulmonary inflammatory response (increased IL-8 in BAL) was earlier (24h) than the systemic inflammatory response (48 h). These observations suggest that the main organ in the systemic inflammatory acute response is lung. So, we recommend the clinical use of mixed talc without small particles to induce safety pleurodesis.
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Ultrastructural and functional characterization of myofibroblasts in lung diseasesKarvonen, H. (Henna) 18 February 2014 (has links)
Abstract
Pulmonary fibrosis, lung cancer and chronic obstructive pulmonary disease (COPD) are severe diseases and common death causes worldwide. Due to the lack of an effective therapy, the investigation of cell biological mechanisms behind these diseases is essential.
An activation of stromal cells, including myofibroblasts, is a main feature found in the pathogenesis of lung diseases. Myofibroblasts express alpha-smooth muscle actin (α-SMA), have specific ultrastructure, produce extracellular matrix proteins and possess contractile capacity. Detailed structure and function of myofibroblasts and their roles in healthy and diseased lung are not yet wholly understood. The investigation of the myofibroblasts may further offer novel tools for the acquisition of proper diagnosis, prognosis and medical treatment.
The study aimed to characterize the ultrastructural, functional and disease-specific features of stromal cells, particularly myofibroblasts, in interstitial and malignant lung diseases. The functional properties evaluated here were differentiation, invasive and contractile properties. The study material included in vitro stromal cells cultured from bronchoalveolar lavage (BAL) fluids. The appearance and location of myofibroblasts in different lung compartments of non-smokers and the COPD-patients were examined in vivo. The cells were investigated by light and electron microscopy. The α-SMA expression was analysed by gene or protein assays.
The study demonstrated that stromal cells could be cultured from diagnostic BAL fluid samples and lung tissues. Cultured cells were a mixture of fibroblasts and myofibroblasts. A small proportion of cells exhibited progenitor-like features. Myofibroblasts revealed differential features in electron microscopy and invasive or contractile assays. When studying tissues from healthy and COPD lungs, myofibroblasts were located both in alveoli and airways. In alveoli myofibroblasts localized in widened alveolar tips which were newly described structures and locations of myofibroblasts in healthy and diseased lung. The amount of myofibroblasts in large airways, but not in peripheral lung, was increased in COPD. We concluded that myofibroblasts have several locations in normal and COPD lung, which suggests a function both in pulmonary regeneration and the pathogenesis of COPD. Smoking altered the phenotype of myofibroblasts regardless of its origin. / Tiivistelmä
Keuhkofibroosi, keuhkosyöpä ja keuhkoahtaumatauti (COPD) ovat kansallisesti ja maailmanlaajuisesti yleisiä ja kuolemaan johtavia sairauksia. Taudinmääritys ja hoito ovat vaativia, eikä kaikille potilaille ole parantavaa hoitoa. Keuhkosairauksien kaikkia solubiologisia mekanismeja ei vielä tunneta, mikä on yksi syy lääkekehityksen ongelmiin.
Interstitiaaleissa ja pahanlaatuisissa keuhkosairauksissa esiintyy paljon aktiivisia sidekudossoluja, kuten muuntuneita fibroblasteja eli myofibroblasteja. Ne tunnistetaan hienorakenteesta, jota voidaan tutkia elektronimikroskoopilla. Myofibroblastit ilmentävät myös solun sisäistä sileän lihaksen alfa-aktiinia (α-SMA), tuottavat sidekudoksen proteiineja ja kykenevät supistumaan. Myofibroblastien hienorakenteen ja toiminnan selvittäminen voi antaa lisätietoa keuhkosairauksien syntymekanismeista, jolloin diagnostiikkaa, ennustetta sekä hoitoja voidaan arvioida paremmin.
Väitöskirjassa selvitettiin myofibroblastien hienorakennetta ja toimintaa eri keuhkosairauksissa. Tutkitut toiminnalliset ominaisuudet olivat erilaistumispotentiaali, invasiivisuus ja supistumiskyky. Sairauksien kliinistä käyttäytymistä ja potilaiden tupakointitottumuksia tarkasteltiin suhteessa solubiologiatason havaintoihin. Tutkimusmateriaali kerättiin taudinmäärityksen yhteydessä interstitiaalisia keuhkosairauksia, keuhkoahtaumatautia tai keuhkosyöpää sairastavilta potilailta.
Tulosten mukaan bronkoalveolaarihuuhtelunesteestä (BAL) ja keuhkokudospaloista voidaan soluviljelymenetelmin kasvattaa ja ylläpitää solulinjoja. Viljellyt solut muodostivat sekasolupopulaatiota, joissa esiintyi pääosin fibroblasteja ja vaihteleva osuus myofibroblasteja. Pieni osa soluista ilmensi kantasoluille tyypillisiä piirteitä. Myofibroblastien tyyppipiirteet ja toiminnalliset ominaisuudet vaihtelivat taudeittain. Kudoksessa myofibroblasteja ilmentyi sekä keuhkorakkuloissa että ilmateissä. Keuhkorakkulatasolla myofibroblastit sijoittuivat irrallisten alveoliseinämien laajentuneisiin päihin, joita ei ole aiemmin tutkittu tieteellisessä kirjallisuudessa myofibroblastien yhteydessä. Keuhkoahtaumatauti ja tupakointi vähensivät näiden rakenteiden määrää perifeerisessä keuhkossa, kun taas suurissa ilmateissä keuhkoahtaumatauti lisäsi myofibroblasteja. Päättelimme, että myofibroblastit edistävät keuhkoahtaumataudin syntyä isoissa ilmateissä, mutta saattavat osallistua keuhkojen korjaukseen keuhkorakkuloissa ja pienissä ilmateissä.
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Desenvolvimento de um ensaio do tipo ELISA indireto utilizando anti-soro policlonal produzido em coelho contra a proteína SP-A suína para quantificar SP-A no lavado broncoalveolar humano. / Development of an indirect ELISA using porcine pulmonary SP-A polyclonal antibody to measure human pulmonary surfactant protein A concentration on bronchoalveolar lavage.Dirce Sakauchi 25 March 2008 (has links)
As colectinas pulmonares SP-A e SP-D são marcadores específicos de doenças pulmonares. A determinação destas proteínas por ensaios imunoenzimáticos permite aos clínicos correlacionarem seu papel funcional durante o desenvolvimento do processo patológico baseado nas anormalidades de suas concentrações. Como o lavado broncoalveolar (BAL) é uma amostra que permite estudar as proteínas secretadas pelo epitélio pulmonar em quaisquer circunstâncias, foi proposto o desenvolvimento de um ELISA indireto capaz de detectar SP-A no BAL humano usando um anti-soro policlonal contra SP-A suína produzido em coelho. SP-A suína foi purificada por protocolo que acopla precipitação ácida do extrato pulmonar suíno e cromatografia de afinidade. O anti-soro reagiu com as duas espécies de SP-A testadas: humana e suína. A curva padrão foi otimizada utilizando como calibrador a SP-A purificada de pacientes com artrite reumatóide. A faixa selecionada da curva de calibração foi de 0,312 to 5,0 mg/mL usando a diluição 1:1000 do anticorpo. O limite de detecção da curva foi de 0,625 mg/mL. / The lung collectins SP-A and SP-D are specific markers for lung diseases. Determination of amounts of these proteins using polyclonal and monoclonal antibodies on ELISA assays enabled clinicians to predict their role in the course of the lung disease process based on abnormalities on their concentrations. As the bronchoalveolar lavage (BAL) is a sample that permits to study the proteins secreted by the lung epithelium at any conditions, we proposed to develop an indirect ELISA able to detect SP-A in the BAL using polyclonal rabbit antiserum, raised against porcine SP-A. Porcine SP-A was purified by a protocol that includes an acid precipitation of the porcine pulmonary extract before affinity chromatography. The antiserum reacted with the two tested species porcine and human. The calibration curve were optimized, using human SP-A purified from patients with rheumatoid arthritis as human antigen calibrator. The selected calibration curve range was 0.312 to 5.0 mg/mL using the antiboby dilution 1:1.000. The detection limit of the standard curve was 0.625 mg/mL.
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Sequentielle Genotypisierung von Pseudomonas aeruginosa-Isolaten und Übereinstimmung von bakteriologischen Proben aus dem oberen und unteren Respirationstrakt von Patienten mit cystischer FibroseJung, Andreas 26 October 2005 (has links)
Die Frage nach adäquaten mikrobiologischen und molekulargenetischen Methoden, um die Kolonisation des Respirationstrakts von Mukoviszidose-Patienten mit Pseudomonas aeruginosa nachzuweisen und zu charakterisieren, wird kontrovers diskutiert. Von 38 klinisch stabilen Patienten mit cystischer Fibrose (CF) wurden sequentiell im Abstand von 18 Monaten Proben aus Rachenabstrich, Sputum und Bronchiallavage (BAL) entnommen und bezüglich Pseudomonas-Nachweis untersucht. Die Pseudomonas-Stämme wurden mittels Random Amplified Polymorphic DNA (RAPD)-Analyse und Pulsfeld-Gelelektrophorese (PFGE) von DNA-Makrorestriktionsfragmenten typisiert und bezüglich der Frage nach genetisch divergierenden Isolaten innerhalb des selben Individuums sowie nach möglichen longitudinalen genetischen Veränderungen evaluiert. Sensitivität, negative und positive prädiktive Werte und Spezifität, um eine P. aeruginosa-Besiedlung zu erkennen, waren 36%, 74%, 83% und 96% im Falle der Kulturen aus dem Oropharynx von nicht-expektorierenden Patienten und 92%, 94%, 100% und 100% für Sputumkulturen von expektorierenden Probanden. RAPD-Analyse und PFGE waren in der Lage, zwischen unterschiedlichen Pseudomonas-Stämmen zu diskriminieren, wobei nur die DNA-Makrorestriktion zwischen Subtypen unterscheiden konnte. Die Genotypen der Pseudomonas-Isolate aus Rachenabstrich und Sputum divergierten in 55% und 40% zu den Isolaten der BAL. Longitudinale Variationen des Genotyps wurden in 62% der Fälle beobachtet, die Hälfte davon war nur mittels bronchoskopisch gewonnener Proben erkennbar. Zusammengefasst besitzen Sputumproben bezüglich des Pseudomonas-Nachweises dieselbe Wertigkeit wie Kulturen aus der BAL, während Rachenabstriche in einer frühen Krankheitsphase für die Charakterisierung der bakteriellen Flora des unteren Respirationstrakts wenig geeignet sind. Die Methode der DNA-Makrorestriktion kann als zuverlässige Technik für epidemiologische Untersuchungen empfohlen werden. Unterschiedliche Genotypen innerhalb desselben Individuums und longitudinale genetische Alterationen sind häufig, jedoch unter Umständen nur bronchoskopisch nachweisbar. / There is controversy about adequate specimen to detect and characterise colonisation of cystic fibrosis (CF) airways by Pseudomonas aeruginosa. Oropharyngeal, sputum and bronchoalveolar lavage (BAL) samples were evaluated sequentially from 38 stable CF patients for the detection of P. aeruginosa. Pseudomonas strains were typed by random amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis (PFGE) of DNA macrorestriction fragments. The occurrence of genetically different isolates within the same host and longitudinal variations in the genotype during repeated examinations was assessed. Sensitivity, negative and positive predictive values and specificity to detect P. aeruginosa were 36%, 74%, 83% and 96% for oropharyngeal cultures in non-expectorating patients and 92%, 94%, 100% and 100% for sputum cultures from expectorating patients, respectively. RAPD analysis and PFGE were suitable to characterize P. aeruginosa CF isolates, although only DNA macrorestriction was able to distinguish between identical and closely related strains. Genotypes of Pseudomonas isolates recovered from oropharyngeal swabs and sputum differed to the strains recovered by bronchoscopy in 55% and 40%, respectively. In 62% longitudinal variations in the genotype occurred. Half of these alterations were only detectable from bronchoscopically obtained samples. In conclusion, sputum samples have the same value as specimens from BAL to detect P. aeruginosa colonisation, whereas cultures from the oropharynx are not suitable for characterising the bacterial conditions in the CF lungs in an early disease state. DNA macrorestriction is recommended as an excellent tool for epidemiological investigations. Different genotypes within the same host and longitudinal genetic alterations are common and may be detectable in the BAL fluid exclusively.
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Comparison of the effects of low dose and high dose inhaled corticosteroid treatment of mild to moderate asthma in adults.Baraket, Melissa, mbaraket@med.usyd.edu.au January 2008 (has links)
Doctor of Philosophy (PhD) / Asthma is a chronic inflammatory disease of the airways. Corticosteroid medication is the most effective currently available treatment. Complications of corticosteroid therapy are dose-dependent, however, the clinical efficacy of varying doses of inhaled corticosteroids has been studied with mixed results. A randomized, double-blind, parallel group study was used to evaluate the inhaled corticosteroid dose-response relationship for clinical endpoints and in vitro parameters of underlying airway inflammation and remodelling. The mannitol provocation test with Forced Oscillation Technique (FOT) was used to derive potential dose-differentiating endpoints. In vitro inflammatory markers were measured in alveolar macrophages from bronchoalveolar lavage. Basement membrane thickness was measured from bronchial biopsies. Eleven nonasthmatic subjects were enrolled for comparison. This thesis addresses the null hypothesis that there is no significant difference in clinical and biological effects between low dose (200mcg/day, n=11) and high dose (1000mcg/day, n=11) treatment (for 6-7 weeks) with inhaled fluticasone propionate (FP) for a range of clinical outcomes and in vitro markers of airway inflammation and remodelling. Significant changes after FP included increased FEV1, reduced airway hyperresponsiveness (AHR) (by FOT and FEV1), exhaled nitric oxide and Juniper symptom score. In addition, significant reductions occurred in expression of GM-CSF, TNF-alpha and IL-1ra in macrophages. A lower baseline FOT-derived respiratory system conductance was predictive of a greater degree of improvement in symptoms. No statistically significant differences in the changes after treatment between low and high dose FP were found in spirometry, exhaled nitric oxide, symptom scores, AHR, alveolar macrophage cytokine levels (GM-CSF, TNF-alpha, IL-1ra, IL-10) and basement membrane thickness, although there were trends towards greater improvements in many of the parameters after high dose FP. Basement membrane thickness appeared to be reduced by high dose FP, although this reduction was not statistically significant. There was a weak, but statistically significant, negative correlation between basement membrane thickness and FOT-derived conductance (r2=0.135, p=0.042). With the recognition of the limitations in the interpretation of these data, the results suggest that, in previously steroid naïve mild to moderate asthmatics, there may be only minimal benefit derived from an additional 800µg/day of inhaled fluticasone above the low dose of 200µg/day.
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