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Several attempts have been made to describe the relation that exists between tobacco smoke and emphysema, through different experimental models of the active smoker. Despite the negative effects that involuntarily inhaled tobacco smoke can have on the lung, no experimental model of the passive smoker has been proposed. In this study, an experimental model(More)
BACKGROUND The increase in the distal air spaces which takes place with age is the only sufficiently documented datum for differentiation between the senile and the adult lung. There are other pulmonary components which may be modified as the lung enters the phase of old age, but they have not as yet been sufficiently studied. The purpose of this study is(More)
The lung is an imperfect elastic body and for this reason dissipates energy. The energy applied to the lung in inspiration is not recovered in expiration. The property of dissipating energy receives the name of hysteresis. Lung hysteresis can be quantified because it applies to the area between the ascending and descending portions of the pressure-volume(More)
BACKGROUND It was hypothesized that the evolution towards the senile lung is progressive, being initiated in the adult stage; and for this reason changes similar to those described in the senile lung can be detected in the lungs of middle-aged rats. To test the hypothesis, the following design was used. The lungs of two groups of rats, adult (mean age of 16(More)
BACKGROUND A morphometric study of the rat lung was done to determine the importance, within the precision of a morphometric study, of the sample size in relation to the quality of the image and to propose a method for the quantification of lung collagen fiber. METHODS Sixty Wistar rats, divided into two age groups consisting of adult and old rats, were(More)
HYPOTHESIS The changes in pulmonary volume taking place during respiration are accompanied by the opening and closing of the alveoli, with the number of alveoli open, at the same transpulmonary pressure (TPP) differing, depending on whether the lung is insufflated or deflated. MATERIAL AND METHODS Seventy 344 Fischer rats divided into five groups. Group 1(More)
This study investigated the effect of cigarette smoke exposure and the potential protection N-acetylcysteine (NAC) in rat lungs. Forty-eight rats were exposed to cigarette smoke (CS) for 10 weeks, without (CS group) or with (CS+NAC group) oral intake of NAC 200 mg x rat(-1) x day(-1), or to fresh air (Control). All rat lungs were assessed in terms of lung(More)
During ageing, a progressive deterioration in the pulmonary function, which can be accelerated by exposure to tobacco smoke, takes place. The hypothesis that the initial age of exposure to tobacco smoke is a factor of utmost importance in the development of emphysema is proposed. Eighty-six rats, aged nineteen months at the time of sacrifice, were used and(More)
OBJECTIVE Describe the morphological changes that take place in the lung parenchyma and in the airways during the respiratory cycle with a view to establishing a relationship between them. SUBJECTS Adult Wistar rats. INTERVENTIONS The lungs were fixed at seven different points in the respiratory cycle: Inflation, 10 and 20 cm. transpulmonary pressure,(More)
The resistance to airflow that develops in most obstructive processes takes place in the small airways. The aim of the present paper is to describe bronchial hysteresis morphometrically in a respiratory cycle model. As a working hypothesis, it is proposed that the changes that take place in the respiratory tract during the respiratory cycle are related to(More)