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.

[Exposition markers: mineralogical analysis in the sputum and the bronchoalveolar lavage--asbestos bodies--uncoated fibres].

The aim of mineralogical analysis of lung tissue, bronchoalveolar lavage (BAL) and sputum is to characterize individuals' exposure to asbestos fibres by identifying markers of this; asbestos bodies (AB) and uncoated fibres. The techniques of mineralogical analysis, habitually used to identify AB and uncoated fibres, are respectively optical microscopy (OM) and analytical electronic microscopy (EM). Correlations between levels of retention of AB in lung tissue, BAL and sputum have been established and validated threshold values indicating a high probability of significant exposure exist.

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.

[Exposure to asbestos and the indoor environment].

A link between the inhalation of asbestos fibres and the outcome of benign and malignant respiratory diseases has been established from numerous epidemiological data in occupational settings. Occupational exposure limit values have been established with a gradual lowering of these over time. Conversely, there are few epidemiological data dealing with exposure in the indoor environment.

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.

Anthracofibrosis attributed to mixed mineral dust exposure: report of three cases.

Anthracofibrosis, defined as bronchial luminal narrowing with black pigmentation of the overlying mucosa, has been attributed to tuberculosis. Three patients with anthracofibrosis without mycobacterial infection are described who had previous occupational exposure to mixed dusts. CT scans showed calcified hilar lymph nodes in two patients.

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.

Occupational exposures and lung cancer in New Caledonia.

Aims: To study the associations between occupational exposures and the risk of lung cancer in New Caledonia.

Methods: All cases diagnosed between January 1993 and December 1995 (228 lung cancers) and 305 population controls were included. Detailed information on lifetime job history, smoking, and other potential risk factors was collected by interview.

[Bronchial anthracosis and pulmonary mica overload].

Introduction: The discovery of anthracotic plaques generally suggests either a history of tuberculosis or occupational exposure to dust. Other etiologies should, however, be considered.

Case Reports: A 60-year-old Iranian woman presented with a history of dyspnoea and with chest radiography demonstrating calcified hilar lymph nodes and interstitial lung disease.

Asbestos bodies in the sputum of asbestos workers: correlation with occupational exposure.

A cross-sectional medical survey including collection of three consecutive sputum samples was carried out among 270 retired workers of a textile and friction materials factory, in order to investigate the relationship between asbestos body identification and asbestos exposure. The individual cumulative asbestos exposure, determined by means of a plant-specific job-exposure matrix based on asbestos air measurements in the workshops, proved to be heavy with a mean cumulative exposure of 217 fibres x mL(-1) x yr. Macrophages and asbestos bodies were identified in sputum samples by light microscopy.

[Measurement of asbestos fibers in the air: description and limitations of the measuring techniques used].

Since the beginning of this century a wide range of methods were used to evaluate the asbestos exposure of workers. Instruments such as the konimeter, thermal precipitator, impinger or tyndallometer were employed to collect dust samples. Currently, the membrane filter method associated with phase contrast optical microscopy is widely accepted.

Environmental exposure to tremolite and respiratory cancer in New Caledonia: a case-control study.

A case-control study on respiratory cancers was conducted in New Caledonia (South Pacific), where a high incidence of malignant pleural mesothelioma had been observed. The disease pattern suggested an environmental exposure to asbestos. The first results showed that, in some areas, tremolite asbestos derived from local outcroppings was used as whitewash (locally named "pö").

[The assessment of asbestos exposure].

The aim of the study is to present the principles of assessing asbestos exposure in two different contexts: that of a patient suffering from pleuropulmonary pathology that could be attributed to asbestos and that of a group possible exposed to asbestos. In the first case this evaluation concerns past exposure and depends typically on information obtained during the course of an interview with the patient. In the second case, the exposure is assessed by atmospheric analysis.

The use of a new static device based on the collection of the thoracic fraction for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy.

A new static device, the CATHIA sampling head, based on the collection of the thoracic fraction is proposed for the assessment of the airborne concentration of asbestos fibres by transmission electron microscopy. By comparison with a standard aerosol sampling head, it has been shown that this sampler reduces the total mass concentration, but does not introduce any change in the most common index used to characterize an asbestos aerosol fibre, that is the concentration of fibres with length greater than 5 microns, diameter less than 3 microns and length to diameter ratio greater than 3. The homogeneity of the deposited dust on the collection filter favours the use of this sampling head with both the indirect and direct preparation methods.

[Retrospective study of pneumoconiosis in Champagne-Ardenne].

This study was carried out in two departments of Champagne-Ardenne. The aim was to assess the level of retrieval in patient population suffering from pneumoconiosis who were hospitalised with this disorder, compared to another population who had contracted the same disease in the working environment and were known to the local social security benefit office in the North East (CRAMNE). A list of 77 names of hospitalised patients had been obtained following requests for mineralogical analysis addressed to a specialised national laboratory.

[Potential role of environmental and domestic exposure to tremolite in pleural cancer in New Caledonia].

A previous study of respiratory cancers in New Caledonia (1978-1987) showed an excess risk of pleural cancer in this South Pacific French Territory, leading to the identification of an environmental pollution. In some villages, the residents use for their houses a whitewash made from a rock derived from local outcroppings. Analysis of samples of rock and whitewash showed that they consisted of tremolite asbestos.

Biopersistence of nonfibrous mineral particles in the respiratory tracts of subjects following occupational exposure.

Transmission electron microscopy analysis (TEMA) was used to analyze the bronchoalveolar lavage fluid (BALF) of 262 subjects occupationally exposed (OE) to nonfibrous mineral particles (NFMP) and 42 controls not occupationally exposed to mineral dusts. OE subjects were divided into three groups according to the lapse of time since last exposure: < or = 1 year and < 10 years (E2), > or = 10 years (E3). The total BALF mineral particle concentration was significantly higher in OE patients than in controls and was closely related to the time lapse since last exposure to NFMP (median values for OE, 7.

Environmental asbestotic pleural plaques in northeast Corsica: correlations with airborne and pleural mineralogic analysis.

We report a prevalence study of environmental pleural plaques in subjects over 50 years old from the northeastern Corsican village of Murato, built on asbestos surface deposits. The percentage of plaques was 41%, versus 7.5% in the control village of Vezzani.

Retention of asbestos bodies in the lungs of welders.

Examination of asbestos bodies (AB) retained in the lungs is a useful way of assessing past occupational exposure to this material. AB retention has been extensively studied in workers directly exposed to asbestos, but less so in those end users, such as welders, who use asbestos-containing products. We therefore retrospectively studied AB retention in 211 welders, for whom biological testing procedures had been requested by a chest physician, between 1988 and 1991.