Quantification of short and long asbestos fibers to assess asbestos exposure: a review of fiber size toxicity.

The fibrogenicity and carcinogenicity of asbestos fibers are dependent on several fiber parameters including fiber dimensions. Based on the WHO (World Health Organization) definition, the current regulations focalise on long asbestos fibers (LAF) (Length: L ≥ 5 μm, Diameter: D < 3 μm and L/D ratio > 3). However air samples contain short asbestos fibers (SAF) (L < 5 μm).

Role of metal oxide nanoparticles in histopathological changes observed in the lung of welders.

Background: Although major concerns exist regarding the potential consequences of human exposure to nanoparticles (NP), no human toxicological data is currently available. To address this issue, we took welders, who present various adverse respiratory outcomes, as a model population of occupational exposure to NP.The aim of this study was to evaluate if welding fume-issued NP could be responsible, at least partially, in the lung alterations observed in welders.

Differential mutation profiles and similar intronic TP53 polymorphisms in asbestos-related lung cancer and pleural mesothelioma.

Given the interest in defining biomarkers of asbestos exposure and to provide insights into asbestos-related and cell-specific mechanisms of neoplasia, the identification of gene alterations in asbestos-related cancers can help to a better understanding of exposure risk. To understand the aetiology of asbestos-induced malignancies and to increase our knowledge of mesothelial carcinogenesis, we compared genetic alterations in relevant cancer genes between lung cancer, induced by asbestos and tobacco smoke, and malignant pleural mesothelioma (MPM), a cancer related to asbestos, but not to tobacco smoke. TP53, KRAS, EGFR and NF2 gene alteration analyses were performed in 100 non-small cell lung cancer (NSCLC) patients, 50 asbestos-exposed and 50 unexposed patients, matched for age, gender, histology and smoking habits.

Pulmonary carcinoid tumors and asbestos exposure.

Objectives: The hypothesis that asbestos exposure may have more specific associations with particular histological types of lung cancer remains controversial. The aim of this study was to analyze the relationships between asbestos exposure and pulmonary carcinoid tumors.

Methods: A retrospective case-control study was conducted in 28 cases undergoing surgery for pulmonary carcinoid tumors and aged >40 years and in 56 controls with lung cancer of a different histological type, matched for gender and age, from 1994 to 1999, recruited in two hospitals in the region of Paris.

A comparative transmission electron microscopy study of titanium dioxide and carbon black nanoparticles uptake in human lung epithelial and fibroblast cell lines.

Several studies suggest that the biological responses induced by manufactured nanoparticles (MNPs) may be linked to their accumulation within cells. However, MNP internalisation has not yet been sufficiently characterised. Therefore, the aim of this study was to compare the intracellular uptake of three different MNPs: two made of carbon black (CB) and one made of titanium dioxide (TiO(2)), in 16HBE bronchial epithelial cells and MRC5 fibroblasts.

Oxidative stress and proinflammatory effects of carbon black and titanium dioxide nanoparticles: role of particle surface area and internalized amount.

The ubiquitous presence of nanoparticles (NPs) together with increasing evidence linking them to negative health effects points towards the need to develop the understanding of mechanisms by which they exert toxic effects. This study was designed to investigate the role of surface area and oxidative stress in the cellular effects of two chemically distinct NPs, carbon black (CB) and titanium dioxide (TiO(2)), on the bronchial epithelial cell line (16HBE14o-). CB and TiO(2) NPs were taken up by 16HBE cells in a dose-dependent manner and were localized within the endosomes or free in the cytoplasm.

p16INK4A inactivation mechanisms in non-small-cell lung cancer patients occupationally exposed to asbestos.

Epidemiological studies have shown that asbestos fibers constitute the major occupational risk factor and that asbestos acts synergistically with tobacco smoking to induce lung cancer. Although some somatic gene alterations in lung cancer have been linked to tobacco smoke, few data are available on the role of asbestos fibers. P16/CDKN2A is an important tumor suppressor gene that is frequently altered in lung cancer via promoter 5'-CpG island hypermethylation and homozygous deletion, and rarely via point mutation.

Impairment of NO-dependent relaxation in intralobar pulmonary arteries: comparison of urban particulate matter and manufactured nanoparticles.

Background And Objectives: Because pulmonary circulation is the primary vascular target of inhaled particulate matter (PM), and nitric oxide is a major vasculoprotective agent, in this study we investigated the effect of various particles on the NO-cyclic guanosine monophosphate (cGMP) pathway in pulmonary arteries.

Methods: We used intrapulmonary arteries and/or endothelial cells, either exposed in vitro to particles or removed from PM-instilled animals for assessment of vasomotricity, cGMP and reactive oxygen species (ROS) levels, and cytokine/chemokine release.

Results: Endothelial NO-dependent relaxation and cGMP accumulation induced by acetylcholine (ACh) were both decreased after 24 hr exposure of rat intrapulmonary arteries to standard reference material 1648 (SRM1648; urban PM).

Assessment of environmental and domestic exposure to tremolite in New Caledonia.

In this study, the authors characterized exposure to asbestos in the population of New Caledonia, an area where a high mesothelioma incidence was found to be associated with the use of a tremolite-containing whitewash on dwellings. The authors collected airborne samples from various sources. Lung tissue samples or bronchoalveolar lavage fluids were available for 80 subjects, who were interviewed regarding their residential and occupational histories.