Relationships between ferruginous bodies and uncoated asbestos fibers in lung tissue

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.

Malignant Mesothelioma in a Motor Vehicle Mechanic

Case reports remain an important source of data in the debate over the carcinogenic effect of asbestos-containing automotive friction products. This report documents a case of pleural mesothelioma accompanied by asbestos bodies in the lung tissue of a career auto mechanic with no other known sources of exposure. Previously unreported historical and contemporary exposure data are also discussed in the context of providing additional support for the proposition that work with asbestos-containing automotive products presents a risk of significant exposure. While there remains a body of negative epidemiology that fails to find an increased risk of disease among auto workers, those data must be approached with caution. Many of those studies have drawn technical criticisms, which are beyond the scope of this report, but they remain a key part of the legal defense mounted by defendant-companies who are involved in asbestos-related litigation. This ongoing debate provides the context for the continued relevance of case reports such as this one, as well as the presentation of new and previously unpublished exposure data.

Elemental composition of ferruginous bodies and occupational categories: analyses and case studies in Mexico

Inorganic fibers form part of the complex mixture of environmental pollutants in Mexico City and in general locations. Upon entering the lungs, some of those fibers are transformed into ferruginous bodies (FB) that can be used as biological markers of exposure to fibers. Hence, the objectives of this study were, first, to describe the most frequent types of FB found in the lungs, and second, to determine the elemental composition of the cores of some of those FB. A total of 264 lung samples collected from autopsies performed at the National Institutes of Health in Mexico City were analyzed. The FB were obtained by digesting the samples in commercial bleach and all the FB were then collected in 0.45 µm Millipore membranes. All the FB obtained from each case were counted directly under bright field microscopy, and then classified by morphology. Results showed from 14.5 FB/g in Category 1 (housewives), to 50.2 FB/g for samples from Category 5 (construction workers), and 152 FB/g for Category 6 (miners). Significant differences were found upon comparing samples from Categories 5/6 to Category 1 (p < 0.05). Type 1 FB were the most frequent ones seen in the samples from Categories 1 to 5. Elemental analyses of the cores of several FB found aluminosilicates, fiberglass, tremolite and amosite asbestos among others. In conclusion, residents of Mexico show exposures to a variety of fibers that induce FB including asbestos.

Mesothelioma and analysis of tissue fiber content

The strong relationship between mesothelioma and asbestos exposure is well established. The analysis of lung asbestos burden by light and electron microscopy assisted to understand the increased incidence of mesothelioma in asbestos mining and consuming nations.The data on the occupational exposure to asbestos are important information for the purpose of compensation of occupational disease No. 4105 (asbestos-associated mesothelioma) in Germany.However, in many cases the patients have forgotten conditions of asbestos exposure or had no knowledge about the used materials with components of asbestos. Mineral fiber analysis can provide valuable information for the research of asbestos-associated diseases and for the assessment of exposure. Because of the variability of asbestos exposure and long latency periods, the analysis of asbestos lung content is a relevant method for identification of asbestos-associated diseases. Also, sources of secondary exposure, so called "bystander exposition" or environmental exposure can be examined by mineral fiber analysis.Household contacts to asbestos are known for ten patients (1987-2009) in the German mesothelioma register; these patients lived together with family members working in the asbestos manufacturing industry.Analysis of lung tissue for asbestos burden offers information on the past exposure. The predominant fiber-type identified by electron microscopy in patients with mesothelioma is amphibole asbestos (crocidolite or amosite). Latency times (mean 42.5 years) and mean age at the time of diagnose in patients with mesothelioma are increasing (65.5 years). The decrease of median asbestos burden of the lung in mesothelioma patients results in disease manifestation at a higher age.Lung dust analyses are a relevant method for the determination of causation in mesothelioma. Analysis of asbestos burden of the lung and of fiber type provides insights into the pathogenesis of malignant mesothelioma. The most important causal factor for the development of mesothelioma is still asbestos exposure.

Synergistic effect of air pollution and habitual smoking on the retention of inorganic fibers identified as ferruginous bodies in autopsy cases in Mexico City

In order to evaluate the synergistic effect of habitual smoking and air pollution in Mexico City on the retention of inorganic fibers, ferruginous bodies (FB) were quantified as markers of exposure to inorganic fibers in lung digests from 426 autopsy cases. FB were isolated from 426 lung digests from cases with several lung diseases. The results revealed more retention of FB in the smokers group than in non-smokers: 38 FB per gram (FB/g) versus 11.2 FB/g, respectively (p < 0.05). Male smokers living in Mexico City increased their median to 54 FB/g. This contrasts with the median of outside residents: 11.2 FB/g (p < 0.002). Housewives and manual laborers increased their medians when the smoking habit was positive: from 11 to 14 FB/g, and from 16 to 21.5 FB/g, respectively. There is an effect of tobacco smoke on the retention of more fibers identified as FB when the individuals are males and Mexico City residents.

Stability of ferruginous bodies in human lung tissue following death, embalmment, and burial

The identification of asbestos bodies in tissue sections is an indicator of past exposure to longer asbestos fibers. These structures are formed in lung tissue as a consequence of interactions with pulmonary macrophages resulting in the deposition of a ferroprotein (ferruginous) coating on the fiber. While the process of ferruginous body formation is known to take months in animal tissue, there is no published information on the stability of ferruginous bodies in tissue following death. The material assessed in the present study was obtained from lung material collected from an exhumed body approximately 8(1/2) mo after death, embalmment, and burial. Tissue sections were reviewed for the presence of asbestos bodies. Additional pieces of lung tissue were digested, with the digestate being evaluated by light microscopy for ferruginous bodies and by electron microscopy for uncoated asbestos fibers and core analysis of asbestos bodies. Classical ferruginous (asbestos) bodies were found in abundance in the tissue sections including in areas with fibrosis. The levels of uncoated asbestos fibers and classical appearing ferruginous bodies (asbestos bodies) were consistent with occupational levels of tissue burden. The data from this study indicate that ferruginous bodies remain morphologically stable within the tissue for months following death, embalmment, and burial. Thus the lung tissue from this exhumed individual was usable not only to pathologically confirm asbestosis but also to provide quantitative data of occupational exposure to asbestos.

Tyler asbestos workers: mortality experience in a cohort exposed to amosite

OBJECTIVES

To examine the causes of death among 1130 former workers of a plant in Tyler, Texas dedicated to the manufacture of asbestos pipe insulation materials. This cohort is important and unusual because it used amosite as the only asbestiform mineral in the production process. High level exposure of such a specific type was documented through industrial hygiene surveys in the plant.

METHODS

Deaths were ascertained through various sources including data tapes from the Texas Department of Health and the national death index files. As many death certificates as possible were secured (304/315) and cause of death assigned. After select exclusions, 222 death certificates were used in the analysis. Causes of death were compared with age, race, and sex specific mortalities for the United States population with a commercial software package (OCMAP Version 2.0).

RESULTS

There was an excess of deaths from respiratory cancer including the bronchus, trachea, and lung (standardised mortality ratio (SMR) 277 with 95% confidence interval (95% CI) 193 to 385). Four pleural mesotheliomas and two peritoneal mesotheliomas were identified. The analysis also showed an increasing risk of respiratory malignancy with increased duration of exposure including a significant excess of total deaths from respiratory cancer with less than six months of work at the plant (SMR 268 with 95% CI 172 to 399).

CONCLUSIONS

The importance of the cohort lies with the pure amosite exposure which took place in the plant and the extended period of latency which has followed. The death certificate analysis indicates the pathogenicity of amosite, the predominant commercial amphibole used in the United States. These data confirm a link between amosite asbestos and respiratory malignancy as well as mesothelioma.