Objectives: To estimate exposures to asbestos fibers of specific sizes among asbestos textile manufacturing workers exposed to essentially pure chrysotile using data from transmission electron microscopy (TEM) and to evaluate the extent to which the risk of lung cancer varies with fiber length and diameter. Methods: 3803 workers employed for at least 1 day between 1 January 1950 and 31 December...

The control of DNA integrity in mammalian cells is important to maintain the cell homeostasis and prevent neoplastic transformation. Control of cell division and cell death permits repair or elimination of damaged cells. Since asbestos fibers can produce DNA damage, chromosome alterations and apoptosis in several sorts of cells, including mesothelial cells, it was interesting to investigate cel...

The mechanism of carcinogenic action of asbestos remains unclear but the physical properties of the fiber appear to be important in this process. Asbestos may cause multinucleate giant cell formation primarily by interfering with the normal course of mitosis. We evaluated the cytotoxicity and multinucleate giant cell formation induced by crocidolite and chrysotile in Chinese hamster lung fibrob...

The aim of this work was to inspect the presence asbestos fibers in colon tissue from a patient, with history indirect exposure and affected by cancer, who underwent surgery. Variable pressure scanning electron microscopy, coupled energy dispersive spectroscopy (VP-SEM/EDS), used for identification inorganic their morphological—chemical characterization. Fresh samples both, healthy area close n...

Binding of asbestos fibers to the cell surface appears to be important in the initiation of intracellular signaling events as well as in initiation of particle uptake by the cell. We have previously shown that cigarette smoke increases the uptake of asbestos fibers by tracheal epithelial cells in explant culture. Whether smoke acts by increasing surface binding of fibers is not known. In this s...

Inhaled asbestos fibers may contribute to three-fourths of malignant mesotheliomas diagnosed in men and almost 40% of cases diagnosed in women. Bans on the manufacture and sale of amphibole asbestos fibers are expected to reduce the incidence of mesothelioma, but the long latency period from initial exposure to clinical disease means that people exposed before bans were enacted will continue to...

Asbestos-related risks have been estimated on the basis of extrapolations from the past, when high-dose occupational exposures were frequent. The linear no-threshold (LNT) dose-response pattern has generally been assumed for the low exposure levels. However, applicability of the LNT hypothesis to low asbestos exposures has never been proven. Asbestos fibers are present in the natural environmen...

There has been a longstanding debate about the potential contribution of chrysotile asbestos fibers to mesothelioma risk. The failure to resolve this debate has hampered decisive risk communication in the aftermath of the collapse of the World Trade Center towers and has influenced judgments about bans on asbestos use. A firm understanding of any health risks associated with natural chrysotile ...

This study compared pulmonary effects of para-aramid respirable-sized, fiber-shaped particles (RFP) (p-aramid fibrils) and chrysotile asbestos fiber exposures in rats. Additional p-aramid inhalation studies were conducted in hamsters to compare species responses. The hamster results are preliminary. The parameters studied were clearance/biopersistence of inhaled p-aramid RFP or size-separated a...

Asbestos induces a constellation of biological responses in cells of the respiratory tract that are similar to those of classical tumor promoters. In this regard, induction of ornithine decarboxylase (ODC) activity and increased incorporation of |3H]thymidine have been documented after addition of crocidolite and chrysotile asbestos to a hamster trachea! epithelial cell line (J. M. Landesman an...