Protocol of Lung Particulate Analysis by Electron Transmission Microscopy for Decoding Occupational History From Lung Retention

Although measurement of lung ‘fiber burden’ has been used in a variety of occupational studies, few protocols have been developed to assess systematically the quantity and type of both fibrous and non-fibrous particles of occupational origin. Such a protocol was designed to relate total lung paniculate content to detailed job-matrices derived from exposure histories in a series of cancer patients interviewed prior to death. Fragments of tissue that had been formalin-fixed or embedded in paraffin were used after tissue identification by two pathologists. The preparation and analytical protocols were optimized so that a statistically representative number of particles excluding endogenous particles could be counted and reasonably characterized according to their morphology and chemical composition by transmission electron microscopy. The average log-values of dust burden for certain minerals that were extracted from lung tissue samples of subjects belonging to the asbestos, silica and metals groups of exposure were statistically different.