Browsing by Author "Lisboa, C"

Now showing 1 - 5 of 5
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    Bleomycin-induced chronic lung damage does not resemble human idiopathic pulmonary fibrosis
    (AMER THORACIC SOC, 2001) Borzone, G; Moreno, R; Urrea, R; Meneses, M; Oyarzun, M; Lisboa, C
    Administration of bleomycin into the lungs of experimental animals has been utilized as a model to understand human pulmonary fibrosis. Most of the studies, however, have focused on early stages of the lung reaction. We hypothesized that chronic stages of the model may not mimic idiopathic pulmonary fibrosis, since in preliminary studies, lung volume and compliance were not decreased. Eight male Sprague-Dawley rats receiving intratracheal bleomycin (0.5 U/100 g body weight) underwent measurement of FRC, inspiratory capacity, and lung compliance 120 d later. Lung histologic changes were evaluated using light microscopy. Eight rats without intervention served as controls. Results show that our model, in early stages, has histologic changes no different from those previously described elsewhere. In chronic stages, however, the model does not behave as a restrictive syndrome: FRC is normal or increased, whereas lung compliance is normal. Focal peribronchiolar inflammation and fibrosis associated with paracicatricial emphysematous changes are the main histologic features of long-term lung remodeling after bleomycin. We conclude that while the chronic stages of the model may be informative in understanding mechanisms of fibrosis, care should be taken not to extrapolate to human idiopathic pulmonary fibrosis. We speculate that the model might resemble a particular subgroup of human interstitial lung disease, namely, those involving peribronchiolar structures.
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    Breathing pattern and gas exchange at peak exercise in COPD patients with and without tidal flow limitation at rest
    (EUROPEAN RESPIRATORY SOC JOURNALS LTD, 2001) Diaz, O; Villafranca, C; Ghezzo, H; Borzone, G; Leiva, A; Milic Emili, J; Lisboa, C
    Expiratory flow limitation (FL) at rest is frequently present in chronic obstructive pulmonary disease (COPD) patients. It promotes dynamic hyperinflation with a consequent decrease in inspiratory capacity (IC), Since in COPD resting IC is strongly correlated with exercise tolerance, this study hypothesized that this is due to limitation of the maximal tidal volume (VT,(max)) during exercise by the reduced IC, The present study investigated the role of tidal FL at rest on: 1) the relationship of resting IC to VT,(max) and 2) on gas exchange during peak exercise in COPD patients.
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    Effect of inspiratory muscle training with an intermediate load on inspiratory power output in COPD
    (MUNKSGAARD INT PUBL LTD, 1998) Villafranca, C; Borzone, G; Leiva, A; Lisboa, C
    There is very little information about the effect of inspiratory muscle training on inspiratory how (V'I) and thus an power output (PO) in patients with chronic obstructive pulmonary disease (COPD). In this study me aimed to evaluate the changes induced by training on the determinants of pg),
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    Effects of noninvasive ventilation on lung hyperinflation in stable hypercapnic COPD
    (EUROPEAN RESPIRATORY SOC JOURNALS LTD, 2002) Diaz, O; Begin, P; Torrealba, B; Jover, E; Lisboa, C
    Two previous uncontrolled studies have suggested that noninvasive mechanical ventilation (NIMV) in patients with hypercapnic chronic obstructive pulmonary disease (COPD) improves arterial blood gas tensions by decreasing lung hyperinflation with the consequent reduction in inspiratory loads and changes in ventilatory pattern. The aim of this randomised placebo-controlled study was to determine whether these mechanisms play a pivotal role in the effects of NIMV on arterial blood gases.
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    Physiological and clinical effects of diurnal noninvasive ventilation in hypercapnic COPD
    (EUROPEAN RESPIRATORY SOC JOURNALS LTD, 2005) Diaz, O; Begin, P; Andresen, M; Prieto, ME; Castillo, C; Jorquera, J; Lisboa, C
    To assess the clinical impact of noninvasive mechanical ventilation (NIMV) on stable hypercapnic chronic obstructive pulmonary disease, changes in exercise capacity, dyspnoea and simple physiological parameters were evaluated. The time course of these effects during treatment and recovery was also assessed.