Guidelines for mineral fibre analyses in biological samples: report of the ERS Working Group. European Respiratory Society

Asbestos-Related lung Cancer: An underappreciated oncological issue

Asbestos, a group of class I (WHO) carcinogenic fibers, is the main cause of mesothelioma. Asbestos inhalation also increases the risk to develop other solid tumours with lung cancer as the most prominent example [91]. The incidence of asbestos-related lung cancer (ARLC) is estimated to be to six times larger than the mesothelioma incidence thereby becoming an important health issue [86]. Although the pivotal role of asbestos in inducing lung cancer is well established, the precise causal relationships between exposures to asbestos, tobacco smoke, radon and 'particulate' (PM2.5) air pollution remain obscure and new knowledge is needed to establish appropriate preventive measures and to tailor existing screening practices[22,61,65]. We hypothesize that a part of the increasing numbers of lung cancer diagnoses in never-smokers can be explained by (historic and current) exposures to asbestos as well as combinations of different forms of air pollution (PM2.5, asbestos and silica).

Development of a protocol of isolation of nanoparticles from patients' broncho-alveolar lavages for their in vitro toxicity assessment

To investigate potential correlations between human exposure to inhaled particles and pathological effects, the biological monitoring of nanoparticles in broncho-alveolar lavages (BAL) from patients has been proposed. To better understand the underlying mechanisms of toxicity, we propose to couple this biomonitoring of nanoparticles to their in vitro toxicity assessment. However, BAL obtained from regular clinical practice are conditioned with sodium hypochlorite solution (in a 50% v/v ratio), which is toxic to cells. The aim of this study was to develop a protocol to neutralize sodium hypochlorite, allowing to properly investigate the toxicity of the nanoparticles BAL contain. We first tried to neutralize chemically the sodium hypochlorite using H2O2, ascorbic acid or sodium ascorbate but this approach was unsuccessful. In addition, standard toxicology assays (MTT, LDH) could not be used because of interference with neutralizing solutions. We thus changed strategy and used ultracentrifugation to isolate nanoparticles from the sodium hypochlorite solution, with satisfactory extraction yields (88 to 100%). We then incubated the extracted nanoparticles with macrophages from the RAW264.7 cell line and assessed the cell viability and pro-inflammatory response. This study can be used as a proof-of-concept for further study of the biological impact of nanoparticles. This approach paves the way for studies aiming at a better understanding of the aetiology of some idiopathic diseases and underlying mechanisms.

Occupational interstitial lung diseases

Millions of workers are exposed to substances known to cause occupational interstitial lung diseases (ILDs), particularly in developing countries. However, the burden of the disease is likely to be underestimated due to under-recognition, under-reporting or both. The diagnosis of occupational ILD requires a high level of suspicion and a thorough occupational history, as occupational and non-occupational ILDs may be clinically, functionally and radiologically indistinguishable, leading to delayed diagnosis and inappropriate management. A potential occupational aetiology should always be considered in the differential diagnosis of ILD, as removal from the workplace exposure, with or without treatment, is a key therapeutic intervention and may lead to significant improvement. In this article, we provide an overview of the 'traditional' inorganic dust-related ILDs but also address idiopathic pulmonary fibrosis and the immunologically mediated chronic beryllium disease, sarcoidosis and hypersensitivity pneumonitis, with emphasis on the importance of surveillance and prevention for reducing the burden of these conditions. To this end, health-care professionals should be specifically trained about the importance of occupational exposures as a potential cause of ILD.

Asbestos: Mineralogical features and fiber analysis in biological materials

Asbestos is a mineral with unique physical and chemical properties that make it highly resistant to heat, fire, and corrosion. Nevertheless, exposure to asbestos fibers has been linked to serious health problems, including lung cancer, mesothelioma, and asbestosis. Despite the ban on asbestos usage, asbestos-related diseases are still a major cause of morbidity and mortality worldwide. Analyzing the mineralogical features and fiber analysis of asbestos in biological materials is critical for scenarios where an asbestos exposure history cannot be obtained, a clinical diagnosis cannot be made, or legal aspects necessitate further investigation. This review outlines the mineralogical features and fiber analysis techniques of asbestos in biological materials.

Lung asbestos fiber burden analysis: effects of the counting rules for legal medicine evaluations

OBJECTIVES

The work shows the effect of counting rules, such as analysis magnification and asbestos fiber dimension to be count (with length ≥5 µm or also asbestos fibers with length <5 µm) in the lung asbestos fiber burden analysis for legal medicine evaluations.

METHODS

On the same lung tissue samples, two different analyses were carried out to count any asbestos fibers with length ≥1 µm and with length ≥5 µm. Results of the amphibole burden of the two analyses were compared by linear regression analysis on log10-transformed values.

RESULTS

The analysis should be carried out at an appropriate magnification and on samples prepared in such a way as they allow the counting of very fine fibers. If the analysis is limited to the asbestos fibers with length ≥5 µm, there is a high risk of not detecting possible residual chrysotile fiber burden and thinner crocidolite asbestos fibers.

CONCLUSIONS

On average we estimated that 1 amphibole fiber with length ≥5 µm corresponds to ∼8 amphibole fibers with length ≥1 µm in the lung. The values of the Helsinki criteria should be updated taking this into account.

Asbestos lung burden does not predicts survival in malignant pleural mesothelioma. A necropsy-based study of 185 cases

INTRODUCTION

Malignant pleural mesothelioma (MPM) is an asbestos-related disease with poor survival. The prognostic role of histological subtype is well established. Some studies (without a biological hypothesis) suggested that higher asbestos lung burden is associated with reduced survival.

OBJECTIVES

We performed a necropsy-based study of MPM patients to analyze the relationship between asbestos lung burden and survival.

METHODS

We selected subjects from two series of necropsies: residents in Brescia province (North-West Italy) and workers (or persons living with them) employed in the Monfalcone shipyards (North-East Italy). Asbestos fibers (AF) and bodies (AB) in lung samples were counted using a scanning electron and an optical microscope respectively. Separately in the two series, we analyzed median survival time and fitted multivariable Cox regression models (adjusted for gender, period and age at diagnosis, and morphology) to calculate hazard ratios (HR) and 95% confidence intervals (CI) for three levels of AF counts (reference: <1 million fibers per gram of dry lung tissue).

RESULTS

We analyzed 185 necropsies, 83 in Brescia and 102 in Monfalcone. Despite a much higher lung burden in Monfalcone patients, median survival was slightly shorter in Brescia (8.3 months) than in Monfalcone (10.2 months). In Brescia, for medium (1-9.9) and high (10+) fiber burden HRs were 0.91 (95% CI 0.54-1.53) and 1.23 (95% CI 0.41-3.70). In Monfalcone, the corresponding HRs were 1.18 (95% CI 0.59-2.35) and 1.63 (95% CI 0.77-3.45).

CONCLUSION

No relationship between asbestos lung burden and survival was found. Histological subtype was the strongest prognostic determinant.

Asbestos danger in central Europe is not yet over - the situation in the Czech Republic

OBJECTIVES

In the Czech Republic, asbestos has been classified as a known human carcinogen since 1984. The use of asbestos-containing products was limited to scenarios where the use of other materials was not possible. Since 1997, the manufacture of asbestos materials has been forbidden, and in 1999, the import, manufacture and distribution of all types of asbestos fibres was legally banned by Act No. 157/1998 Coll. Although the use of asbestos is forbidden, the risk of exposure still exists given the ongoing demolition and reconstruction of buildings in which asbestos has been used. In addition, a novel risk has arisen through the quarrying of asbestos-containing aggregates and their subsequent use. The aim of this paper was to describe and evaluate asbestos in terms of history, legislation, current risk of occupational exposure and its health consequences in the Czech Republic over the last three decades.

METHODS

This retrospective descriptive study used the collected data on occupational exposure and occupational diseases. The counts of workers occupationally exposed to asbestos were obtained from the Registry of Work Categorization; the numbers and structure of occupational diseases caused by asbestos were taken from the Czech National Registry of Occupational Diseases. Data on the total number of mesothelioma cases recorded in the Czech National Cancer Registry was provided by the Institute of Health Information and Statistics of the Czech Republic.

RESULTS

A total of 13,112 subjects were registered as occupationally exposed to asbestos during the period 2001-2020. A total of 687 cases of asbestos-related occupational diseases were reported in the period 1991-2020 in the Czech Republic, comprising 178 cases of asbestosis, 250 cases of pleural hyalinosis, 168 cases of pleural or peritoneal mesothelioma, 90 cases of lung cancer, and one case of laryngeal cancer. The data from the Czech National Cancer Registry, available for a shorter period (1991-2018), reveal 1,389 cases of mesothelioma, of which only ~11% were recognised as occupational, despite the fact that the occupational causality of mesotheliomas is estimated to be up to 90% of mesotheliomas. Moreover, the latency of mesotheliomas since the last occupational exposure reached up to 50 years and this trend is still slightly increasing, unlike asbestosis, where a high cumulative dose of inhaled asbestos is needed. The real proportion of occupational lung cancers may obviously be even higher, especially in smokers, where occupational causes including asbestos are not suspected by most physicians.

CONCLUSION

Czech data on asbestos-related occupational diseases, especially cancers, are grossly underestimated, which is most apparent through the low proportion of mesotheliomas diagnosed as occupational. Asbestos materials in older buildings remained in situ and may represent a danger during reconstruction works. The current source of exposure appears to be quarrying of asbestos-containing aggregate and its subsequent use. Awareness of the professional community is therefore crucial, not only for the possibility of compensating those affected, but also for the early detection of the diseases through the dispensary of exposed persons.

Experimental and Computational Nanotoxicology-Complementary Approaches for Nanomaterial Hazard Assessment

The growing development and applications of nanomaterials lead to an increasing release of these materials in the environment. The adverse effects they may elicit on ecosystems or human health are not always fully characterized. Such potential toxicity must be carefully assessed with the underlying mechanisms elucidated. To that purpose, different approaches can be used. First, experimental toxicology consisting of conducting in vitro or in vivo experiments (including clinical studies) can be used to evaluate the nanomaterial hazard. It can rely on variable models (more or less complex), allowing the investigation of different biological endpoints. The respective advantages and limitations of in vitro and in vivo models are discussed as well as some issues associated with experimental nanotoxicology. Perspectives of future developments in the field are also proposed. Second, computational nanotoxicology, i.e., in silico approaches, can be used to predict nanomaterial toxicity. In this context, we describe the general principles, advantages, and limitations especially of quantitative structure–activity relationship (QSAR) models and grouping/read-across approaches. The aim of this review is to provide an overview of these different approaches based on examples and highlight their complementarity.

Relationship between Occupational Exposure to Airborne Nanoparticles, Nanoparticle Lung Burden and Lung Diseases

The biomonitoring of nanoparticles in patients’ broncho-alveolar lavages (BAL) could allow getting insights into the role of inhaled biopersistent nanoparticles in the etiology/development of some respiratory diseases. Our objective was to investigate the relationship between the biomonitoring of nanoparticles in BAL, interstitial lung diseases and occupational exposure to these particles released unintentionally. We analyzed data from a cohort of 100 patients suffering from lung diseases (NanoPI clinical trial, ClinicalTrials.gov Identifier: NCT02549248) and observed that most of the patients showed a high probability of exposure to airborne unintentionally released nanoparticles (>50%), suggesting a potential role of inhaled nanoparticles in lung physiopathology. Depending on the respiratory disease, the amount of patients likely exposed to unintentionally released nanoparticles was variable (e.g., from 88% for idiopathic pulmonary fibrosis to 54% for sarcoidosis). These findings are consistent with the previously performed mineralogical analyses of BAL samples that suggested (i) a role of titanium nanoparticles in idiopathic pulmonary fibrosis and (ii) a contribution of silica submicron particles to sarcoidosis. Further investigations are necessary to draw firm conclusions but these first results strengthen the array of presumptions on the contribution of some inhaled particles (from nano to submicron size) to some idiopathic lung diseases.

Evaluation of Deposition and Clearance of Asbestos (Detected by SEM-EDS) in Lungs of Deceased Subjects Environmentally and/or Occupationally Exposed in Broni (Pavia, Northern Italy)

Biodurability is one of the main determinants of asbestos hazardousness for human health. Very little is known about the actual persistence of asbestos in lungs and its clearance, nor about differences in this regard between the different mineralogical types of asbestos. The aim of the present study was to evaluate the amount, the dimensional characteristics and the mineralogic kinds of asbestos in lungs (measured using SEM-EDS) of a series of 72 deceased subjects who were certainly exposed to asbestos (mainly crocidolite and chrysotile) during their life. Moreover, we investigated possible correlations between the lung burden of asbestos (in general and considering each asbestos type), as well as their dimension (length, width, and l/w ratio) and the duration of exposure, the latency- in case of malignant mesothelioma (MM), the survival and the time since the end of exposure. In 62.5% of subjects, asbestos burden in lungs was lower that the threshold considered demonstrative for occupational exposure. In 29.1% of cases no asbestos was found. Chrysotile was practically not detected. The mean length of asbestos fibers and the length to width ratio were significantly related to the duration of exposure to asbestos. No other statistically significant correlations were found between the amount and dimensional characteristics of asbestos (nor with the relative amount of each asbestos type) and the other chronological variables considered. In conclusion, it was pointed out that chrysotile can be completely removed from human lungs in <8 years and, instead, amphiboles persist much more time. The present results suggest, as well, that the finding of no asbestos in lungs cannot rule out the attribution of MM to asbestos (in particular, chrysotile) inhaled in an occupational setting. This point is of crucial importance from a legal point of view.

Chemo-physical properties of asbestos bodies in human lung tissues studied at the nano-scale by non-invasive, label free x-ray imaging and spectroscopic techniques

In the lungs, asbestos develops an Fe-rich coating (Asbestos Body, AB) that becomes the actual interface between the foreign fibers and the host organism. Conventional approaches to study ABs require an invasive sample preparation that can alter them. In this work, a novel combination of x-ray tomography and spectroscopy allowed studying unaltered lung tissue samples with chrysotile and crocidolite asbestos. The thickness and mass density maps of the ABs obtained by x-ray tomography were used to derive a truly quantitative elemental analysis from scanning x-ray fluorescence spectroscopy data. The average mass density of the ABs is compatible with that of highly loaded ferritin, or hemosiderin. The composition of all ABs analyzed was similar, with only minor differences in the relative elemental fractions. Silicon concentration decreased in the core-to-rim direction, indicating a possible partial dissolution of the inner fiber. The Fe content in the ABs was higher than that possibly contained in chrysotile and crocidolite. This finding opens two opposite scenarios, the first with Fe coming from the fiber bulk and concentrating on the surface as long as the fiber dissolves, the second where the Fe that takes part to the formation of the AB originates from the host organism Fe-pool.

Asbestos bodies count and morphometry in bulk lung tissue samples by non-invasive X-ray micro-tomography

The number of the Asbestos Bodies (AB), i.e. asbestos that developed an iron-protein coating during its permanence in biological tissues, is one of the most accessible markers of asbestos exposure in individuals. The approaches developed to perform AB count in biological tissues are based on the manual examination of tissue digests or histological sections by means of light or electron microscopies. Although these approaches are well established and relatively accessible, manual examination is time-consuming and can be reader-dependent. Besides, approximations are applied because of the limitations of 2D readings and to speed up manual counts. In addition, sample preparation using tissue digests require an amount of tissue that can only be obtained by invasive surgery or post-mortem sampling. In this paper, we propose a new approach to AB counting based on non-destructive 3D imaging, which has the potential to overcome most of the limitations of conventional approaches. This method allows automating the AB count and determining their morphometry distribution in bulk tissue samples (ideally non-invasive needle biopsies), with minimal sample preparation and avoiding approximations. Although the results are promising, additional testing on a larger number of AB-containing biological samples would be required to fully validate the method.

Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples

Increased mortality due to malignant mesothelioma has been demonstrated by several epidemiologic studies in the area around Broni (a small town in Lombardy, northern Italy), where a factory producing asbestos cement was active between 1932 and 1993. Until now, the inorganic fiber burden in lungs has not been investigated in this population. The aim of this study is to assess the lung fiber burden in 72 individuals with previous occupational and/or anthropogenic environmental exposure to asbestos during the activity of an important asbestos cement factory. Inorganic fiber lung burden was assessed in autoptic samples taken from individuals deceased from asbestos-related diseases using a scanning electron microscope equipped with an energy-dispersive spectrometer. Significant differences in the detected amount of asbestos were pointed out among the three types of exposure. In most lung samples taken from patients who died of mesothelioma, very little asbestos (or, in some cases, no fibers) was found. Such subjects showed a significantly lower median amount of asbestos as compared to asbestosis. Almost no chrysotile was detected in the examined samples. Overall, crocidolite was the most represented asbestos, followed by amosite, tremolite/actinolite asbestos, and anthophyllite asbestos. There were significant differences in the amount of crocidolite and amosite fibers according to the kind of exposure. Overall, these findings provide novel insights into the link between asbestos exposure and mesothelioma, as well as the different impacts of the various types of asbestos on human health in relation to their different biopersistences in the lung microenvironment.

Lung Asbestos Fibre Burden and Pleural Mesothelioma in Women with Non-occupational Exposure

BACKGROUND

Malignant pleural mesothelioma (MPM) due to environmental and familial (domestic) asbestos exposure is well recognized. However, information on cumulative asbestos dose in subjects affected by MPM is limited.

OBJECTIVES

To evaluate the residual lung asbestos fibre and asbestos body burden in women with MPM with past environmental and/or familial asbestos exposure.

METHODS

We collected lung samples from autopsies regarding 15 non-occupationally asbestos-exposed MPM cases, divided in three groups: (i) familial exposure from the Fincantieri shipyards in Monfalcone (No. 7), (ii) environmental and familial asbestos exposure from the asbestos-cement plant Fibronit in Broni (No. 6), and (iii) environmental exposure from the Fibronit plant (No. 2). Asbestos body (AB) and fibres (AF) per gram of dry lung tissue were counted by optical and scanning electron microscopy, respectively, and expressed as geometric means and standard deviations (GM, GSD).

RESULTS

GM/GSD of AB counts were 6123/9.6 (Group 1), 13 800/10.4 (Group 2), and 8400/1.1 (Group 3); GM/GSD of AF were 0.6/2.1 (Group 1), 7.9/2.1 (Group 2), and 6.0/2.3 (Group 3) million. Pleural plaques were observed in 12 cases.

CONCLUSIONS

Exclusive familial exposure to asbestos determined cumulative doses close to those observed in moderate occupational exposure circumstances. Our results also suggest that combined environmental and familial exposures may cause unexpectedly high cumulative fibre doses.

Discrepancies of asbestos body and fiber content between formalin-fixed and corresponding paraffin embedded lung tissue

BACKGROUND

Formalin-fixed lung tissue and paraffin blocks containing peripheral lung tissue obtained from subjects with an occupational asbestos exposure are both regarded to be suitable to determine asbestos load. Because sample preparation of paraffin blocks requires a more intense treatment than formalin-fixed tissue, we tested whether asbestos analysis of formalin-fixed lung tissue and paraffin blocks obtained from the same patients deliver comparable results.

MATERIALS AND METHODS

We determined numbers of asbestos bodies (AB) and amphibole asbestos fibers (AF) in formalin-fixed lung tissue and corresponding paraffin blocks from 36 patients. For AB counts, samples were digested in sodium hypochlorite. For AF analysis, tissue was freeze-dried and then ashed. Results were reported as numbers of AB and AF per gram dry lung tissue.

RESULTS

Both AB counts as well as AF counts were lower in paraffin blocks than formalin-fixed lung tissue. Compared to formalin-fixed tissue, the limit of detection was higher for paraffin blocks, rendering more results from paraffin blocks not interpretable than from formalin-fixed tissue (8 samples versus 1 for AB and 15 samples versus 4 for AF).

DISCUSSION AND CONCLUSION

Asbestos analysis of paraffin blocks may lead to underestimation of asbestos exposure. This should be considered when assessing occupational asbestos exposure through lung dust analysis in medico-legal evaluation.

Radiographic change over 11 years in a patient with asbestos-related pleural disease

Asbestos-related pulmonary conditions such as benign asbestos pleural effusion (BAPE) and diffuse pleural thickening (DPT) can develop after many years of asbestos exposure. These conditions cause progressing constrictive deficit in pulmonary function which may lead to respiratory failure and death. We report the case of a 72-year-old man with asbestos-related BAPE and DPT which developed approximately 40 years after occupational asbestos exposure, leading to chronic respiratory failure and death. We were able to observe his clinical course including computed tomography (CT) scan evaluation over 11 years. In addition to this observation, moderate asbestos body concentration was confirmed in autopsy-derived lung tissue. There are few case reports that showed radiographic course of asbestos-related pulmonary disorder initiated as BAPE, followed by unilateral DPT and later bilateral DPT that was histologically proven with asbestos body. We consider his clinical course is important in managing this disease, especially in early phase.

Wild rats as urban detectives for latent sources of asbestos contamination

Based on a large body of evidence asbestos minerals have been classified as carcinogens. Despite the Italian ban on asbestos in 1992 and the subsequent remediation activities, latent sources of contamination may still represent a hazard where asbestos were particularly used. Using wild rats as sentinel animals, this study aimed at uncovering sites with the greatest potential for non-occupational exposure to asbestos in the city of Casale Monferrato (Piedmont Region, Italy), where the largest Italian manufacturing plant of asbestos-cement had been active. During the study period (2013-2015) a total of 40 wild rats were captured from 16 sampling capture points. The lungs of wild rats have been investigated by using scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The SEM-EDS detected the presence of asbestos fibers (tremolite/actinolite, amosite, and chrysotile) in rats' lungs from 11 sampling points. The hypothetical rats' home-range and the observed site-specific concentration of asbestos fibers per gram of dry lung tissue were used to identify areas to be targeted by additional search of latent sources of asbestos. In conclusion, our results showed that the use of wild rats as sentinel animals may effectively integrate the strategies currently in use to reduce the exposure to asbestos.

Reactive mesothelial hyperplasia mimicking mesothelioma in an African green monkey (Chlorocebus aethiops)

A spontaneous reactive mesothelial hyperplasia occurred in a female, 15.7-year-old African green monkey (grivet; Chlorocebus aethiops). At necropsy, massive effusions were found in the abdomen, the thorax, and the pericardium. Additionally, multiple small, beige-gray nodules were detected on the serosal surfaces of the abdominal organs. Histopathologically, the mesothelial cells resembled the epithelioid subtype of a mesothelioma, but no infiltrative or invasive growth could be demonstrated. The mesothelial cells on the thoracis, liver, and intestinal serosa were accompanied by chronic serositis. Mesothelial cells expressed cytokeratin, vimentin, calretinin, desmin, Wilms Tumor 1 (WT-1) protein, and epithelial membrane antigen (EMA). Cells were negative for carcinoembryonic antigen (CEA), cluster of differentiation 15 (CD15), and podoplanin. Ultrastructurally, cells revealed a moderate amount of microvilli of medium length, perinuclear tonofilament bundles, and long desmosomes. In fluorescence in situ hybridization (FISH) for the detection of characteristic gene loss (p16; CDKN2A), NF2, and MTAP, no deletions were detected. No asbestos fibers and no presence of Simian virus 40 antigen (SV40) could be demonstrated.

Respirable inorganic fibers dispersed in air and settled in human lung samples: Assessment of their nature, source, and concentration in a NW Italy large city

The present investigation represents a new approach useful to evaluate the general population risk correlated with environmental exposure to air dispersed inorganic fibers. The used method is based on the evaluation of the respirable inorganic fibers both air dispersed in a big city and contained in lungs of the general population following their respiration. Moreover, these data allow to identify the sources of dispersion (anthropogenic or natural) in air of the inorganic fibers and therefore to apply strategies to improve air quality. To describe this approach, we investigated air samples from a big city in NW Italy and lung inorganic burden of people here lived. This paper reports the data of the airborne inorganic fibers detected in two sampling campaign (2014 and 2016), in 24 districts of Torino (Piemonte - NW Italy), and in some autoptic lungs of general population lived here. The airborne fibers (collected on mixed-cellulose esters membrane) were characterized by SEMEDS. The identified inorganic fiber species were assigned to 5 classes, one of these including 2 types of asbestos. These last are grouped as tremolite/actinolite asbestos. They are dispersed from natural sources (i.e. certain kinds of rocks outcropping in the city surrounding areas). In no-one of the 24 districts of Torino their concentration highlighted a situation of asbestos pollution in place. A correlation with inorganic fibers (collected on mixed-cellulose esters membrane and characterized by SEM-EDS) detected in lung tissue samples of 10 subjects lived in Torino all their life and without professional exposure to asbestos were attempted. The only types of fibers identified as asbestos are tremolite/actinolite asbestos, and they match those detected in air sampling. The number of fibers per 1 g of tissue dry weight is lower than the quantities reported as indicative of significant asbestos exposure. We observed interesting gender differences.

Asbestos, Smoking and Lung Cancer: An Update

This review updates the scientific literature concerning asbestos and lung cancer, emphasizing cumulative exposure and synergism between asbestos exposure and tobacco smoke, and proposes an evidence-based and equitable approach to compensation for asbestos-related lung cancer cases. This update is based on several earlier reviews written by the second and third authors on asbestos and lung cancer since 1995. We reevaluated the peer-reviewed epidemiologic studies. In addition, selected in vivo and in vitro animal studies and molecular and cellular studies in humans were included. We conclude that the mechanism of lung cancer causation induced by the interdependent coaction of asbestos fibers and tobacco smoke at a biological level is a multistage stochastic process with both agents acting conjointly at all times. The new knowledge gained through this review provides the evidence for synergism between asbestos exposure and tobacco smoke in lung cancer causation at a biological level. The evaluated statistical data conform best to a multiplicative model for the interaction effects of asbestos and smoking on the lung cancer risk, with no requirement for asbestosis. Any asbestos exposure, even in a heavy smoker, contributes to causation. Based on this information, we propose criteria for the attribution of lung cancer to asbestos in smokers and non-smokers.

Malignant peritoneal mesothelioma in a boar who lived in Calabria (Italy): Wild animal as sentinel system of human health

Mesothelioma is a tumor of the serosal membranes described both in human and veterinary medicine. While in humans the relationship between mesothelioma and exposure to asbestos and some other asbestiform minerals is well known, in animals it is still difficult to establish. In this paper a case of malignant peritoneal mesothelioma probably related to asbestos exposure in a wild boar is described. At post-mortem evaluation the peritoneum, diaphragm and serosal surface of liver and kidneys showed isolated to coalescent multiple nodular lesions. Samples from diaphragm, liver and lung were collected to perform microbiological and histological investigations. To assess the presence of asbestos and/or other asbestiform minerals, SEM-EDS investigations were performed on organs and soil samples collected from the area where the wild boar lived. Microbiological investigations were negative for Mycobacterium species. Gross and histological examination were compatible with a biphasic mesothelioma, with nodules composed of epithelioid and sarcomatoid elements with high pleomorphism. Immunohistochemistry revealed only multifocal scattered positivity for WT-1 and D2-40. Asbestos fibres were detected in all samples (organs and soil) by SEM-EDS, demonstrating a potential relationship between the neoplasia and the exposure to naturally occurring asbestos (NOA). In conclusion, the results of the present study are further confirmation that wild animals, such as the boar, are suitable sentinels to indicate the risk of environmental exposure to asbestos for human populations.

Asbestos-related disease in upholsterers

Before its use was banned in developed countries, asbestos was widely applied in upholstery. However, the risk of asbestos diseases among upholsterers has only rarely been reported. In this case series, we present a first series of 6 workers employed in small workshops who developed several asbestos-related diseases, including pleural plaques, pleural fibrosis, and asbestosis. Exposures were intermittent and difficult to quantify, but lung asbestos content assessed by bronchoalveolar lavage was high in the 3 patients evaluated. In conclusion, upholstery work should be considered an at-risk occupation for developing asbestos-related diseases during the 20th century.

A method for the quantitative extraction of gold nanoparticles from human bronchoalveolar lavage fluids through a glycerol gradient

Bronchoalveolar lavage (BAL) is a diagnostic procedure which samples the cellular and non-cellular components of the pulmonary epithelial surface. The inherent biological noise of BAL fluids inhibits their direct mineralogical analysis while currently available particle retrieval protocols are suspected to impose quantitative and qualitative bias on the studied particle load. This study presents a simple method for the near-lossless extraction of citrate-capped gold nanoparticles from human BAL fluids at sub-ppm levels which enables their quantitation and surface characterization. This procedure was modeled according to fundamental principles of particle sedimentation and liquid-liquid interdiffusion and was evaluated by a battery of analytical techniques. The extraction yield of gold nanoparticles ranged from 61 to 86%, with a quantitation limit at 0.5 μg ml^-1, as measured by inductively-coupled optical emission spectroscopy. Dynamic light scattering could resolve the hydrodynamic size distribution of extracted particles which returned significantly different photon count rates at various concentrations. Their shape and primary size were easily observable by electron microscopy while atomic force microscopy, Auger electron spectroscopy and X-ray photoelectron spectroscopy could respectively probe the particles' biomolecular corona, detect surface-adsorbed S- and N- species, and identify carbon-based covalent bonds.

Asbestos fibre burden in gallbladder: A case study

The methods conventionally used to determine the burden of asbestos fibres inhaled/incorporated in lung require chemical digestion of the biological matrix before counting/characterising the inorganic fibrous phases under scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS). Asbestos fibres can also be present in extra-pulmonary organs, and we set out to quantify the fibres in gallbladder. Although the standardised procedure requires approximately 5 × 10^-1 g of wet tissue, this amount of tissue is not always available. We applied the procedure on about 9 × 10^-4 g of gallbladder from a patient with known environmental and workplace exposure to asbestos. The patient died of malignant pleural mesothelioma and was also affected by severe bile-tract problems. The traditional procedure of digesting tissue samples in NaClO and filtering the resulting suspension was carried out. The filter was then examined under SEM/EDS using two methods 1. following the standardised procedure to assess the fibre burden in lung by investigating only 2 mm² of the filter (660 microscopic fields), and 2. analysing all the microscopic fields in one-quarter of the filter (about 82 mm²). In parallel, histological sections (prepared in the usual way for medical diagnosis) were analysed without digestion or manipulation of the sample using variable pressure SEM/EDS. The fibre counts obtained using the two methods were of the same order of magnitude, i.e., ∼10⁵ fibres/g of wet tissue. We showed that the counting of fibres in human tissue may be successfully carried out even when a limited amount of tissue is available. We also found that, when exposure to asbestos is considerable, the number of asbestos fibres accumulating in the gallbladder may be significant.

First Identification of Pulmonary Asbestos Fibres in a Spanish Population

INTRODUCTION

This study aimed to characterize, for the first time in Spain, the type of asbestos fibres (AF) in the lungs of exposed and non-exposed populations.

MATERIALS AND METHODS

Lung samples from 38 subjects living in Barcelona and Ferrol, Spain, were studied, which were divided into three groups: Group A-five subjects without known respiratory disease; Group B-20 ex-shipyard workers and Group C-13 patients with lung cancer. After eliminating the organic material, the inorganic residue was analysed using electronic microscopy (EM). To identify the type of fibre, the samples were analysed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX).

RESULTS

All the fibres identified corresponded to amphiboles (crocidolite 45%, anthophyllite 22%, tremolite 16%, amosite 15% and actinolite 3%). In 14 patients (37%), a single type of asbestos was found in the lungs (amosite in two, actinolite in one, anthophyllite in four, crocidolite in five and tremolite in two). Forty-six percent of the AF analysed had a length > 5 µm and a diameter < 0.2 µm.

CONCLUSIONS

The results of this study provide the first data on the type of asbestos retained in the lung of Spanish population. A particularly striking finding is the exclusive retention of amphiboles, which suggests that chrysotile is eliminated after inhalation. Our findings support estimations considering Spain and other southern European countries with similar asbestos imports and consumption at a high risk to develop asbestos-related diseases in the years to come.

The asbestos fibre burden in human lungs: new insights into the chrysotile debate

The traceability of asbestos fibres in human lungs is a matter of discussion especially for chrysotile. This issue is of high significance for differential diagnosis, risk assessment and occupational compensation. At present no intra-individual longitudinal information is available. This study addresses the question whether the asbestos fibre burden in human lungs decreases with time after exposure cessation.

The database of the German Mesothelioma Register was screened for patients with asbestos body counts of at least 500 fibres per gram of wet lung, which had been analysed twice from different tissue excisions at minimum intervals of 4 years.

Twelve datasets with individual longitudinal information were discovered with a median interval of about 8 years (range 4–21 years). Both examinations were performed after exposure cessation (median: surgery, 9.5 years; autopsy, 22 years). Pulmonary asbestos fibre burden was stable between both examinations (median 1623/4269 asbestos bodies per gram wet lung). Electron microscopy demonstrated a preponderance of chrysotile (median 80%).

This study is the first to present longitudinal intra-individual data about the asbestos fibre burden in living human lungs. The high biopersistence of amphiboles, but also of chrysotile, offers mechanistic explanations for fibre toxicity, especially the long latency period of asbestos-related diseases.

Intra-individual longitudinal data display: the asbestos fibre burden in living human lungs is stable over many yearshttp://ow.ly/VtPF30bRETz

The utility of electron microscopy in detecting asbestos fibers and particles in BALF in diffuse lung diseases

Background

In patients with diffuse lung diseases, differentiating occupational lung diseases from other diseases is clinically important. However, the value of assessing asbestos and particles in bronchoalveolar lavage fluid (BALF) in diffuse lung diseases by electron microscopy (EM) remains unclear. We evaluated the utility of EM in detecting asbestos fibers and particles in patients with diffuse lung diseases.

Methods

The BALF specimens of 107 patients with diffuse lung diseases were evaluated. First, detection of asbestos by EM and light microscopy (LM) were compared. Second, the detection of asbestos using surgically obtained lung tissues of 8 of 107 patients were compared with the results of EM and LM in BALF. Third, we compared the results of mineralogical components of particles in patients with (n = 48) and without (n = 59) a history of occupational exposure to inorganic dust.

Results

BALF asbestos were detected in 11 of 48 patients with a history of occupational exposure by EM; whereas asbestos as asbestos bodies (ABs) were detected in BALF in 4 of these 11 patients by LM. Eight of 107 patients in whom lung tissue samples were surgically obtained, EM detected BALF asbestos at a level of >1,000 fibers/ml in all three patients who had ABs in lung tissue samples by LM at a level of >1,000 fibers/g. The BALF asbestos concentration by EM and in lung tissue by LM were positively correlated. The particle fractions of iron and phosphorus were increased in patients with a history of occupational exposure and both correlated with a history of occupational exposure by a multiple regression analysis.

Conclusions

EM using BALF seemed to be superior to LM using BALF and displayed a similar sensitivity to LM using surgically-obtained lung tissue samples in the detection of asbestos. Our results also suggest that detection of elements, such as iron and phosphorus in particles, is useful for evaluating occupational exposure. We conclude that the detection of asbestos and iron and phosphorus in particles in BALF by EM is very useful for the evaluation of occupational exposure.

New insights on the biomineralisation process developing in human lungs around inhaled asbestos fibres

Once penetrated into the lungs of exposed people, asbestos induces an in vivo biomineralisation process that leads to the formation of a ferruginous coating embedding the fibres. The ensemble of the fibre and the coating is referred to as asbestos body and is believed to be responsible for the high toxicological outcome of asbestos. Lung tissue of two individuals subjected to prolonged occupational exposure to crocidolite asbestos was investigated using synchrotron radiation micro-probe tools. The distribution of K and of elements heavier than Fe (Zn, Cu, As, and Ba) in the asbestos bodies was observed for the first time. Elemental quantification, also reported for the first time, confirmed that the coating is highly enriched in Fe (~20% w/w), and x-ray absorption spectroscopy indicated that Fe is in the 3+ oxidation state and that it is present in the form of ferritin or hemosiderin. Comparison of the results obtained studying the asbestos bodies upon removing the biological tissue by chemical digestion and those embedded in histological sections, allowed unambiguously distinguishing the composition of the asbestos bodies, and understanding to what extent the digestion procedure altered their chemical composition. A speculative model is proposed to explain the observed distribution of Fe.

Recommendations for the Diagnosis and Management of Asbestos-Related Pleural and Pulmonary Disease

Asbestos is the term used for a set of mineral silicates that tend to break up into fibers. Its use has been associated with numerous diseases affecting the lung and pleura in particular, all of which are characterized by their long period of latency. Asbestos, moreover, has been recognized by the WHO as a Group IA carcinogen since 1987 and its use was banned in Spain in 2002. The publication in 2013 of the 3rd edition of the specific asbestos health monitoring protocol, together with the development of new diagnostic techniques, prompted the SEPAR EROM group to sponsor publication of guidelines, which review the clinical, radiological and functional aspects of the different asbestos-related diseases. Recommendations have also been made for the diagnosis and follow-up of exposed patients. These recommendations were drawn up in accordance with the GRADE classification system.

Utility of Bronchoalveolar Lavage for the Diagnosis of Asbestos-Related Diseases

INTRODUCTION

Bronchoalveolar lavage (BAL) analysis has been proposed as an objective technique for confirming asbestos exposure. However, the reliability and diagnostic yield of this procedure has not been studied in Spain. The aim of this study was to assess the usefulness of the analysis of asbestos bodies (AB) in bronchoalveolar lavage (BAL) for the diagnosis of asbestos-related diseases (ARD).

METHODS

BAL samples from 72 patients (66 male, mean age 66 years) undergoing bronchoscopy were analyzed. Lung tissue from 23 of these patients was also analyzed. Asbestos exposure was assessed by anamnesis and a review of the patient's medical records. BAL and lung samples were processed and AB count was determined by light microscopy. The accepted threshold value to diagnose asbestos-related diseases was 1 AB/ml BAL or 1000 AB/gr dry tissue.

RESULTS

Thirty-nine patients reported exposure to asbestos. Of these, 13 (33%) presented AB values above 1 AB/ml BAL. In the 33 non-exposed patients, 5 (15%) presented AB values above 1 AB/ml BAL. There was a significant difference between the AB levels of exposed and non-exposed patients (P=.006). The ROC curve showed that a value of 0.5 AB/ml BAL achieved the most satisfactory sensitivity, 46%, and a specificity of 83%. The correlation between AB levels in BAL and lung was 0.633 (P=.002).

CONCLUSIONS

BAL study provides objective evidence of exposure to asbestos. The good correlation between the AB counts in BAL and lung tissue indicates that both techniques are valid for the analysis of asbestos content.

Residual fibre lung burden among patients with pleural mesothelioma who have been occupationally exposed to asbestos

OBJECTIVES

To evaluate the lungs asbestos fibres concentration in participants with malignant pleural mesothelioma (MPM) who have been occupationally exposed.

METHODS

The lung samples were obtained from pleuropneumonectomies or autopsies of 271 male MPMs. The lung samples were examined through scanning electron microscopy. Retrospective assessment was used to assess for asbestos exposure. This study includes 248 MPMs with an occupational exposure defined as either 'definite' or 'probable' or 'possible'.

RESULTS

The participants had finished working in asbestos exposure conditions more than 20 years ago (on average 26.1±11.0 years). The fibre burden resulted with a geometric mean equal to 2.0 (95% CI 1.6 to 2.4) million fibres per gram of dry lung tissue. The burden was higher among participants employed in asbestos textiles industry and in shipyards with insulation material, if compared with construction workers or non-asbestos textile workers or participants working in chemicals or as auto mechanics. 91.3% of MPMs had a detectable amount of amphibole fibres. A strong lung clearance capability was evident among workers exposed to chrysotile fibres. Owing to that, the 1997 Helsinki Criteria for occupational exposure were reached in <35% of cases among participant working in construction, in metallurgical industry, in chemical or textile industry and among those performing brake repair activities.

CONCLUSIONS

The MPM cases are now occurring in Italy in participants who ceased occupational asbestos exposure decades before the analysis. A large majority still shows a residual content of amphibole fibres, but given the lung clearance capability, attribution to occupational exposure cannot rely only on fibres detection.

Diagnosis of Asbestos-Related Diseases: The Mineralogist and Pathologist's Role in Medicolegal Field

Because asbestos diseases represent a complex pattern of legal, social, and political issue, the involvement of the mineralogist and pathologist for a multidisciplinary assessment of its diagnosis helps investigate the relationship between mesothelioma or lung cancer and occupational or environmental asbestos exposure.In the present study, we consider the concentrations of asbestos bodies (ABs) detected by optical microscopy (OM) and scanning electron microscopy (SEM) and the burden of different kinds of mineral fibers (among which is asbestos) identified by SEM combined with an energy dispersive spectrometer (EDS), in 10 lung tissue samples of subjects with occupational and nonoccupational exposure to asbestos.In all subjects with occupational exposure to asbestos, more than 1000 ABs per gram of dry weight were detected both with OM and SEM; this concentration is internationally accepted as suggesting high probability of past occupational exposure to asbestos.In 9 lung samples of the 10 investigated by SEM-EDS different inorganic fibers were found. Asbestos fibers have been identified too, and more than 100,000 fibers per gram of dry weight were detected in subjects with occupational exposure; this concentration is internationally accepted as suggesting high probability of past occupational exposure to asbestos.Instead, when the ABs burden is low or moderate (such as in subjects with absent or probable asbestos exposure), the correlation between ABs concentration determined by OM and those determined by SEM is lost. Therefore, when the ABs value in OM is borderline, the SEM investigation became essential. Furthermore, the mineralogical analysis by SEM-EDS (identification and quantification of inorganic fibers in general and asbestos in particular) of the fibers detected in the lung tissues is very useful, if not necessary, to complete the pathological diagnosis of asbestos-related malignancies in medicolegal field.

Focused X-Ray Histological Analyses to Reveal Asbestos Fibers and Bodies in Lungs and Pleura of Asbestos-Exposed Subjects

Asbestos bodies are the histological hallmarks of asbestos exposure. Both conventional and advanced techniques are used to evaluate abundance and composition in histological samples. We previously reported the possibility of using synchrotron X-ray fluorescence microscopy (XFM) for analyzing the chemical composition of asbestos bodies directly in lung tissue samples. Here we applied a high-performance synchrotron X-ray fluorescence (XRF) set-up that could allow new protocols for fast monitoring of the occurrence of asbestos bodies in large histological sections, improving investigation of the related chemical changes. A combination of synchrotron X-ray transmission and fluorescence microscopy techniques at different energies at three distinct synchrotrons was used to characterize asbestos in paraffinated lung tissues. The fast chemical imaging of the XFM beamline (Australian Synchrotron) demonstrates that asbestos bodies can be rapidly and efficiently identified as co-localization of high calcium and iron, the most abundant elements of these formations inside tissues (Fe up to 10% w/w; Ca up to 1%). By following iron presence, we were also able to hint at small asbestos fibers in pleural spaces. XRF at lower energy and at higher spatial resolution was afterwards performed to better define small fibers. These analyses may predispose for future protocols to be set with laboratory instruments.

Asbestos bodies in bronchoalveolar lavage in the 21st century: a time-trend analysis in a clinical population

OBJECTIVES

Asbestos bodies (AB) in bronchoalveolar lavage (BAL) can be detected by light microscopy and their concentration is indicative of past cumulative asbestos exposure. We assessed clinical and exposure characteristics, as well as possible time trends, among patients in whom AB had been quantified in BAL.

METHODS

BAL samples obtained from 578 participants between January 1997 and December 2014 were available for analysis. The processing of samples and the microscopic analysis were performed by a single expert and 76% of samples came from a single tertiary care hospital, allowing clinical and exposure data to be extracted from patient files.

RESULTS

The study population (95% males) had a mean age of 62.5 (±12.4) years. AB were detected in 55.2% of the samples, giving a median concentration of 0.5 AB/mL (95th centile: 23.6 AB/mL; highest value: 164.5 AB/mL). The AB concentration exceeded 1 AB/mL in 39.4% and 5 AB/mL in 17.8%. A significant decrease from a geometric mean of 0.93 AB/mL in 1997 to 0.2 AB/mL in 2014 was apparent. High AB concentrations generally corresponded with occupations with (presumed) high asbestos exposure. AB concentrations were higher among patients with asbestosis and pleural plaques, when compared with other disease groups. Nevertheless, a substantial proportion of participants with likely exposure to asbestos did not exhibit high AB counts.

CONCLUSIONS

This retrospective study of a large clinical population supports the value of counting AB in BAL as a complementary approach to assess past exposure to asbestos.

The association among ferruginous body, uncoated fibers, asbestos and non-asbestos fibers in lung tissue in terms of length

To demonstrate the correlations between the concentrations of ferruginous body as well as uncoated fiber both of which can be observed with phase-contrast microscope and the concentration of various inorganic fibers including asbestos which requires the observation with TEM or SEM, we measured those indices among Japanese and Korean cases. Though the concentration of ferruginous body in lung tissue is an important index of asbestos exposure, uncoated fibers observed with phase-contrast microscope might be another index especially in such cases with relatively low exposure due to their history of living in a general environment. However, to establish the reliability of uncoated fibers as an index of asbestos exposure, analysis with more cases and from various backgrounds must be carried out.

Anthophyllite asbestos: state of the science review

Anthophyllite is an amphibole form of asbestos historically used in only a limited number of products. No published resource currently exists that offers a complete overview of anthophyllite toxicity or of its effects on exposed human populations. We performed a review focusing on how anthophyllite toxicity was understood over time by conducting a comprehensive search of publicly available documents that discussed the use, mining, properties, toxicity, exposure and potential health effects of anthophyllite. Over 200 documents were identified; 114 contained relevant and useful information which we present chronologically in this assessment. Our analysis confirms that anthophyllite toxicity has not been well studied compared to other asbestos types. We found that toxicology studies in animals from the 1970s onward have indicated that, at sufficient doses, anthophyllite can cause asbestosis, lung cancer and mesothelioma. Studies of Finnish anthophyllite miners, conducted in the 1970s, found an increased incidence of asbestosis and lung cancer, but not mesothelioma. Not until the mid-1990s was an epidemiological link with mesothelioma in humans observed. Its presence in talc has been of recent significance in relation to potential asbestos exposure through the use of talc-containing products. Characterizing the health risks of anthophyllite is difficult, and distinguishing between its asbestiform and non-asbestiform mineral form is essential from both a toxicological and regulatory perspective. Anthophyllite toxicity has generally been assumed to be similar to other amphiboles from a regulatory standpoint, but some notable exceptions exist. In order to reach a more clear understanding of anthophyllite toxicity, significant additional study is needed. Copyright © 2016 John Wiley & Sons, Ltd.

From the definition of silicosis at the 1930 Johannesburg conference to the blurred boundaries between pneumoconioses, sarcoidosis, and pulmonary alveolar proteinosis (PAP)

The 1930 International Labour Office Conference on silicosis in Johannesburg identified silicosis by setting a medicolegal framework to its nosology: as with other occupational illnesses, its medical content was fixed under economic pressure. This article follows a reading of all the proceedings of this conference (debates and reports of experts) to examine their potential impact on the etiology and nosology of other diseases, specifically sarcoidosis and pulmonary alveolar proteinosis (PAP), "idiopathic" diseases in which inorganic particles may be involved. We propose renewed study of the role of inorganic particles in these diseases. To do this, we propose to mobilize detection means such as mineralogical analysis and electron microscopy and in depth interviewing that are currently seldom used in France, in order to establish diagnosis and the potential occupational and environmental origin of these diseases.

The pathologist's view of silicosis in 1930 and in 2015. The Johannesburg Conference legacy

The 1930 International Labour Office Conference on silicosis in Johannesburg was a turning point in the history of silicosis and in the recognition of the associated pathologic patterns. Since 1930, pneumoconioses such as silicosis have become much rarer in developed countries and can now be diagnosed at an early stage based on clinical and radiologic criteria. However, in spite of these advances, pathologists must remember to look for silica in tissues, particularly when clinical and radiologic findings are more uncertain. Furthermore, nowadays pathologists essentially observe silicotic lesions as incidental findings adjacent to lung cancers. In addition to identifying the characteristic lesions, pathologists must also try to identify their causative agent, in the case of crystalline silica firstly by using polarized light examination, followed as appropriate by more sophisticated devices. Finally, pathologists and clinicians must always keep in mind the various implications of exposure to silica compounds in a wide range of diseases.

Asbestos Lung Burden in Necroscopic Samples from the General Population of Milan, Italy

The present study analysed the asbestos lung burden in necroscopic samples from 55 subjects free from asbestos-related diseases, collected between 2009 and 2011 in Milan, Italy. Multiple lung samples were analysed by light microscopy (asbestos bodies, AB) and EDXA-scanning electron microscopy (asbestos fibres and other inorganic fibres). Asbestos fibres were detected in 35 (63.6%) subjects, with a higher frequency for amphiboles than for chrysotile. Commercial (CA) and non-commercial amphiboles (NCA) were found in roughly similar frequencies. The estimated median value was 0.11 million fibres per gram of dry lung tissue (mf g(-1)) for all asbestos, 0.09 mf g(-1) for amphiboles. In 44 (80.0%) subjects no chrysotile fibres were detected. A negative relationship between asbestos mass-weighted fibre count and year of birth (and a corresponding positive increase with age) was observed for amphiboles [-4.15%, 95% confidence interval (CI) = -5.89 to -2.37], talc (-2.12%, 95% CI = -3.94 to -0.28), and Ti-rich fibres (-3.10%, 95% CI = -5.54 to -0.60), but not for chrysotile (-2.84%, 95% CI = -7.69 to 2.27). Residential district, birthplace, and smoking habit did not affect the lung burden of asbestos or inorganic fibres. Females showed higher burden only for amphiboles (0.12 versus 0.03 mf g(-1) in males, P = 0.07) and talc fibres (0.14 versus 0 mf g(-1) in males, P = 0.03). Chrysotile fibres were shorter and thinner than amphibole fibres and NCA fibres were thicker than CA ones. The AB prevalence was 16.4% (nine subjects) with concentrations ranging from 10 to 110 AB g(-1) dry, well below the 1000 AB g(-1) threshold for establishing occupational exposure. No AB were found in subjects younger than 30 years. Our study demonstrated detectable levels of asbestos fibres in a sample taken from the general population. The significant increase with age confirmed that amphibole fibres are the most representative of cumulative exposure.

Significant relationship between the extent of pleural plaques and pulmonary asbestos body concentration in lung cancer patients with occupational asbestos exposure

BACKGROUND

The aim of this study was to elucidate whether there is a relationship between the extent of pleural plaques and pulmonary asbestos body concentration (PABC).

METHODS

The subjects were 207 lung cancer patients with occupational asbestos exposure. We determined the plaque extent by findings on chest images using our own criteria. PABCs were measured in resected or autopsy lung specimens.

RESULTS

There was a significant relationship between plaque extent and PABC. Seventy-five percent of the patients determined to have extensive plaques based on our criteria had a PABC of ≥5,000 asbestos bodies per gram of dry lung tissue, which is one of the certification criteria of lung cancer caused by asbestos for workers' compensation in Japan.

CONCLUSIONS

In lung cancer patients, the plaque extent had a significant positive relationship with the PABC. The plaque extent would be useful as a proxy for PABC for lung cancer compensation purposes.

The wild rat as sentinel animal in the environmental risk assessment of asbestos pollution: a pilot study

Asbestos has been banned in many countries, including Italy. However, sources of exposure may still exist, due to asbestos in-situ or past disposal of asbestos-containing waste. In an urban area with past high environmental exposure, like Casale Monferrato, the lung fiber burden in sentinel animals may be useful to identify such sources. A pilot study was conducted to assess the feasibility of its determination in wild rats, a suitable sentinel species never used before for environmental lung asbestos fiber burden studies. Within the framework of pest control campaigns, 11 adult animals from 3 sites in the urban area of Casale Monferrato and 3 control rats from a different, unexposed town were captured. Further, 3 positive and 3 negative control lung samples were obtained from laboratories involved in breeding programs and conducting experimental studies on rats. Tissue fiber concentration was measured by scanning electron microscopy with energy dispersive spectrometry. Asbestos (chrysotile and crocidolite) was identified in the lungs from rats from Casale Monferrato, but not in control rats and in negative control lung samples. Asbestos grunerite at high concentration was found in positive control lung samples. Measurement of the lung fiber burden in wild rats has proved feasible: it was possible not only to detect, but also to characterize asbestos fibers both qualitatively and quantitatively. The pilot study provides the rationale for using wild rats as sentinels of the soil contamination level in Casale Monferrato, to identify areas with the possible presence of previously unrecognized asbestos sources.