RESUMO
The effect of tobacco smoke on the central and peripheral airways were assessed in humans and rats by direct and indirect methods. In both species tobacco smoke affected the central and peripheral airways. In humans there were apparent decreases in the 1-second forced expiratory volume, peak expiratory flow rate and significant increases in closing volume and closing capacity (P less than 0.001). In rats significant changes were seen in specific airway resistance from the 6th week of exposure onwards. Similarly, airway luminal diameter decreased markedly in tobacco-exposed animals to subthreshold concentrations of acetylcholine (10(-8) M). This decrease was also exposure time dependent. The increased responsiveness of the respiratory system has been attributed to inter alia: (1) increased vagal activity; (2) increased mucus production leading to decreased airway lumen; (3) mucosal swelling due to changed ionic constellation; (4) disturbance of the lungs' defense mechanism; (5) imbalance in and easy accessibility to the adrenoceptors. (AU)
Assuntos
Humanos , Adulto , Pessoa de Meia-Idade , Ratos , 21003 , Masculino , Feminino , Resistência das Vias Respiratórias , Volume de Oclusão , Pulmão/fisiopatologia , Medidas de Volume Pulmonar , Fumaça , Tabagismo , Tabaco , Pulmão/anatomia & histologia , Pico do Fluxo Expiratório , Ratos EndogâmicosRESUMO
Pneometric parameters and closing volume were measured in 950 Afro-Jamaicans of both sexes. Prediction formulae relating each measurement to age and height were constructed. Based on these formulae it is concluded that differences in compartments of the lung exist in Afro-Jamaicans. Closing volume measurements yielded higher values for Afro-Jamaicans than is observed in white populations. It is suggested that in the absence of baseline values an erroneous diagnosis of small airway disease could result. The possibility that the observed differences may have been due to environmental rather than genetic factors is discussed. (AU)
Assuntos
Feminino , Humanos , Masculino , Medidas de Volume Pulmonar , Capacidade Vital , Negro ou Afro-Americano , Fatores Sexuais , JamaicaRESUMO
Prediction equations have been evolved for the assessment of vital capacity, total lung capacity, and the single breath carbon monoxide transfer factor in haemoglobin SS and haemoglobin SC disease. These relationships take account of the growth disorder and anaemia in the sickle-cell states. The results suggest that, in the clinically stable state, and effects of alveolar capillary sickling and haemoconcentration and any altered reactivity of haemoglobins S and C with the test gas are of no significance for clinical respiratory physiology. Sex differences in lung function appear independent of haemoglobin type. (AU)
