Angular and fibrous particles in lung in relation to silica-induced diseases

Introduction: The lung concentration of angular and fibrous particles was measured in cases of lung fibrosis only, in cases of lung fibrosis and lung cancer, and in cases of lung cancer only. These patients worked in different trades (mining, foundries, construction and were not a homogeneous group of exposed workers. Material and methods: Particles, both angular and fibrous, were extracted from lung parenchyma by a bleach digestion method, mounted on copper microscopic grids by a carbon replica technique, and analyzed by transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS). The quartz concentration was also determined by X-ray diffraction (XRD) on a silver membrane filter after extraction from the lung parenchyma. Results: (1) Lung cancer and lung fibrosis cases retained more metal-rich particles (P=0.02) and more angular particles of all sorts (P=0.009) than did lung fibrosis cases only, and the differences were statistically significant. (2) However, more quartz was retained in the lungs in lung fibrosis cases than in lung fibrosis or lung cancer cases, but the difference in the concentrations was not statistically significant. (3) More ferruginous bodies were retained in the lungs in lung cancer and lung fibrosis cases than in cases of lung fibrosis only, and the difference in the concentrations was statistically significant (P=0.02). Conclusion: Results obtained from lung tissue must always be interpreted cautiously. However, these results are consistent with the hypothesis that workers in some trades such as foundries were exposed not only to quartz but also to asbestos, ceramic fibers, metal-rich non fibrous particles, and other likely carcinogenic chemicals. The wide range of particle types identified in the lungs of these workers illustrates the complexity of trying to determine disease origins in these work environments. Epidemiology studies have to control for the exposure to these carcinogens as well as for smoking habits. Received: 8 April 1997 / Accepted: 11 December 1997     

“Rinse and trickle”: a protocol for TEM preparation and investigation of inorganic fibers from biological material

The purpose of this work is to define a sample preparation protocol that allows inorganic fibers and particulate matter extracted from different biological samples to be characterized morphologically, crystallographically and chemically by transmission electron microscopy-energy dispersive spectroscopy (TEM-EDS). The method does not damage or create artifacts through chemical attacks of the target material. A fairly rapid specimen preparation is applied with the aim of performing as few steps as possible to transfer the withdrawn inorganic matter onto the TEM grid. The biological sample is previously digested chemically by NaClO. The salt is then removed through a series of centrifugation and rinse cycles in deionized water, thus drastically reducing the digestive power of the NaClO and concentrating the fibers for TEM analysis. The concept of equivalent hydrodynamic diameter is introduced to calculate the settling velocity during the centrifugation cycles. This technique is applicable to lung tissues and can be extended to a wide range of organic materials. The procedure does not appear to cause morphological damage to the fibers or modify their chemistry or degree of crystallinity. The extrapolated data can be used in interdisciplinary studies to understand the pathological effects caused by inorganic materials.     

利用焦锑酸钾沉淀法和电镜—能谱技术研究失血心肌细胞内Ca~（2＋）的分布

利用焦锑酸钾沉淀法和电镜－能谱技术研究失血心肌细胞内的Ｃａ（２＋）的分布。结果表明：在失血心肌细胞的线粒体和内质网内的Ｃａ（２＋）明显增多。这一结果对探讨失血肌细胞损伤机理具有一定意义。