RESUMEN
Occupational injuries are decreasing due to the improvement in occupational management in the workplace in recent years. However, pneumoconiosis and its complications remain important occupational diseases. Based on the report 'survey on classification for supervision of pneumoconiosis in Japan' performed in 1994, this study compared age, number of years at the job and pulmonary function tests among work types, and examined the characteristics of cases in which pulmonary function results were worse than expected from the chest X-ray findings. In the comparison among work types, mean age was higher and %VC was lower among workers exposed to silica or asbestos, and FEV1.0% appeared to be lower among silica-exposed workers. Multiple regression analysis showed that silica or asbestos-exposed work environments strongly affected %VC. Some cases showed dissociation between the X-ray findings and pulmonary function tests, which appeared to be caused by certain types of work environments. In this study, all the subjects had findings of pneumoconiosis in their chest X-ray. It is necessary to perform a longitudinal survey on pneumoconiosis-free subjects to clarify the precise association of lung function tests with chest X-ray.
Asunto(s)
Polvo , Pulmón/diagnóstico por imagen , Exposición Profesional/efectos adversos , Neumoconiosis/diagnóstico , Pruebas de Función Respiratoria , Amianto/toxicidad , Estudios Transversales , Flujo Espiratorio Forzado , Humanos , Japón/epidemiología , Persona de Mediana Edad , Exposición Profesional/análisis , Exposición Profesional/prevención & control , Neumoconiosis/diagnóstico por imagen , Neumoconiosis/epidemiología , Radiografía , Factores de Riesgo , Dióxido de Silicio/toxicidad , Capacidad VitalRESUMEN
Alveolar macrophages are considered to play a major role in the pathophysiology of lung diseases caused by exposure to various kinds of pathogens and particles. In this study, the cytotoxic effect of different shapes of titanium dioxide (TiO(2)) was evaluated on macrophages using a unique magnetometry method and was compared with conventional methods of lactate dehydrogenase (LDH) release, apoptosis measurement, and morphological observations. Alveolar macrophages obtained from Fischer rats (F344) by bronchoalveolar lavage were incubated in vitro for 18 h with Fe(3)O(4) as a magnetometric indicator and fibrous and particulate forms of TiO(2) as test materials. In the control and particulate exposed group, rapid attenuation of the residual magnetic field, so-called "relaxation," was observed immediately after cessation of the external magnetic field. In comparison, a delay of relaxation was observed in alveolar macrophages exposed to fibrous TiO(2). LDH released into serum-free medium induced by exposure to TiO(2) increased significantly in a concentration-dependent manner in macrophages exposed to fibrous TiO(2), while negligible LDH release was observed in macrophages exposed to particulate TiO(2). The DNA ladder detection method and morphological examination detected no apoptosis in macrophages exposed to 60 micro g/ml of fibrous or particulate TiO(2). Electron microscopic examination revealed vacuolar changes and cell surface damage in macrophages exposed to fibrous TiO(2), but no significant changes in macrophages exposed to particulate TiO(2). The results of magnetometry, LDH release, and electron microscopy suggest that cytotoxicity of TiO(2) depends on the shape of the material.