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PubMedDate not supplied

Recent data on cancer due to asbestos in Germany.

The Authors evaluate the risk of lung cancer and mesothelioma among asbestos workers in Germany. 3,988 workers (3,372 male and 616 female) were included in the study, which took into consideration the branch of the asbestos industry in which they had worked, the duration of their employment and also their smoking habits. At the end of the 12 year follow-up, 3,315 workers were alive and 673 dead. The analysis of cause of death showed an increased risk of dying from lung cancer and pleural and peritoneal mesothelioma, in men as well as in women. The risk was shown to be greatest among workers in the asbestos textile industry and among insulators. A probable multiplicative effect of asbestos exposure and smoking on lung cancer causation was noted.

Adult↗

PubMedDate not supplied

Mesotheliomas following exposure to asbestos used in sugar refineries: report of 12 Italian cases.

Twelve Italian cases of mesothelioma (all the cases but one from the Emilia Romagna Region), following exposure to asbestos used in sugar refinery plants, are reported. Eleven cases arose in workers occupationally exposed, and one in the daughter of an exposed worker, following family contact. Eleven of the cases were pleural and one peritoneal. In the 11 cases following occupational exposure the average latency time was 36.0 (range 23-48) years, and the average age at onset was 63.4 years. In the case which followed family contact, the latency time and the age of the onset were 37 years. This represents the largest series of cases of mesothelioma due to the asbestos present in sugar refinery plants reported to date in the scientific literature. While these cases demonstrate the risk of asbestos mesothelioma in the sugar refinery industry, they in no way give the dimension of the pathological effects of asbestos (and man-made mineral fibres) used in this industry. To assess this risk further research is suggested.

Adult↗

PubMed1996

[Mortality from malignant neoplasms in men occupationally exposed to asbestos dust].

The authors present the results of cancer risk evaluation in the cohort of men occupationally exposed to chrysotile asbestos dust in the plant involved in the production of asbestos packings, uneven fabric, yarn, cords, asbestos and rubber cardboards and friction materials. A retrospective observation, carried out till 31 December 1990, covered 2,403 men employed during the years 1945-73. The cohort accessibility accounted for 90.5%. Cancer risk was evaluated on the basis of standardized mortality ratio (SMR) calculated according to the person-years method. A slightly higher mortality from malignant neoplasms was found in the cohort than in the general population (160 deaths; SMR = 108). A significant excess mortality applied only to one site, namely large intestine (9 deaths; SMR = 232). In the subcohort of workers exposed to a high dose of asbestos dust, a significant increase in total cancer risk was revealed (30 deaths; SMR = 150), including neoplasm of stomach (8 deaths; SMR = 223), large intestine (3 deaths, SMR = 582) and liver (3 deaths, SMR = 373). No significant increase in mortality from lung cancer was observed.

Adult↗

PubMed1996

Malignant peritoneal mesothelioma following asbestos exposure.

Clinical, epidemiological, and pathological studies have demonstrated that asbestosis plays a major role in the etiology of mesothelioma. The direct exposure of workers in industrialized countries to asbestos fibers and nonoccupational household contact elevate the risk of malignant mesothelioma. An increased risk has been found in certain geographic areas of Turkey due to the presence of asbestos deposits and the use of the material known as "white soil" as an insulation. We present a malignant mesothelioma case from rural eastern Turkey with a history of asbestos exposure from using "white soil". We review the epidemiological aspects of asbestos as they relate to mesothelioma.

Asbestos↗

PubMedDate not supplied

[Optical and electron microscopic methods for counting respirable fibers of asbestos: considerations on relative standards].

The paper reports experience of the use of optical and electronic microscope methods for assessment of the concentration of airborne asbestos fibres and their respective identification. The results described are derived from the extensive experience of three Italian university institutes, which have used optical methods of observation for over 35 years (phase contrast technique, at times associated with the use of polarized light) and have examined altogether about 11,000 samples of airborne dust and fibres. After considering in more detail certain values of asbestos fibre concentrations in various environments, measured parallely with optical and electronic microscope, and assessing their basic comparability, attention is drawn to a number of ambiguities and contradictions contained in Law D.M. 6/9/1994, which tends to discourage the use of the optical microscope (especially using the phase contrast technique), without however taking into consideration the improved cost/benefit ratio in the assessment of respirable asbestos fibres present in working and living environments. On this topic, attention is drawn to the fact that the limits for occupational exposure to asbestos, proposed and/or adopted in the international scientific literature, are based on the numerical count of fibres with the optical microscope using the phase contrast technique (MOCF).

Air Pollutants↗

PubMedDate not supplied

Asbestos-related mortality in Italy: a geographical approach.

The present contribution describes two studies of asbestos-related cancer mortality in Italy: an analysis of the geographical distribution of mortality from pleural neoplasms and an investigation into the relationship between pleural and lung cancer mortality in an Italian region, Piedmont. Mortality from malignant pleural neoplasms (ICD-IX Revision 163.0-163.9) has been studied in Italy in the 20 regions and the over 8000 municipalities for the years 1988-92: restriction of analysis to municipalities with at least three observed deaths and statistically significant increases led to identification of areas where occupational and/or environmental exposure to asbestos can have occurred. The analysis of pleural and lung cancer mortality was carried out for the years 1980-87 in Piedmont using an empirical Bayes method for small-area disease mapping; the results showed that the proportion of lung cancer mortality attributable to asbestos exposure was 5.6 and 5.7 percent respectively in men and women. While analyses of routinely collected data are no substitute for ad hoc individual based studies, notwithstanding the limitations of geographical approaches to the study of asbestos-related mortality, investigations carried out at the level of small area populations appear to provide informative results, which might be of value in terms of public health.

Asbestos↗

PubMed1997

[Lung and pleural changes caused by exposure to asbestos].

Asbestos exposure results in an increased risk of nonmalignant as well as of malignant pulmonary and pleural disease. The asbestos-related disease are inexorably progressive (cancer) or insidious (fibrosis), untreatable and widespread in the industrialized and urban world. The identification of these diseases is important because therapy and prognosis differ from the other pulmonary fibrosis. The case reports indicate that careful clinical and histologic examination allows proper diagnosis. Two patients with asbestos-related disease after asbestos exposure are described.

Asbestos↗

PubMed1998

p53 gene mutations in asbestos associated cancers.

The accumulation of mutant p53 protein in cancer cells was observed by immunohistochemistry analysis. DNA was extracted from paraffin-embedded tissue. Exons 5, 7 and 8 were amplified and studied by PCR-SSCP and sequencing analysis. Ten cases of asbestos associated cancer tissue were studied, of which five cases had adenocarcinoma, and the other five had mesothelioma, squamous carcinoma, small cell lung cancer, adenosquamous carcinoma and malignant lymphoma respectively. Employing monoclonal antibody PAb1801, five cases were found to be mutant p53 protein positive. Seven cases were found to have mutations by PCR-SSCP. A total of 7 cases (8 mutations) were found to be positive and 4 cases were found to be positive by both of these analyses. Of the 8 mutations found by SSCP analysis, 4(50%, 4/8) were clustered in exon 8. A high mutation frequency was noticed in adenocarcinoma (80%, 4/5). Sequencing analysis on two specimens revealed two hotspot mutations. In codon 234, TAC for tyrosin was mutated to AAC for asparagine by a T to A transversion of the first letter. In codon 273, CGT for arginine was mutated to AGT for serine by a C to A transversion of the first letter. In conclusion, the mutation of p53 gene is common in asbestos associated cancers. However, the mutational spectrum of asbestos associated cancers might be different from that of non-asbestos associated cancers.

Adenocarcinoma↗

PubMed1998

South African asbestos: production, exports, and destinations, 1959-1993.

Production and export figures of South African asbestos were analyzed over 1959-1993. They show stable sales of chrysotile. Those of crocidolite and amosite reached their peaks in the mid-1970s, after which trade fell drastically, crocidolite to 5% of its earlier peak and amosite to nil. Factors responsible for these virtual collapses were health issues, stricter legislation in First World countries, and litigation. In 1992, 21 countries continued to import crocidolite, although in reduced quantities. In the early 1960s, Europe and North America were the major recipients of South African asbestos. By 1989-91, these regions were surpassed by the Far East, which took over 90% of chrysotile and 70% of amosite. For crocidolite at that time, the Middle East took nearly 40%, Europe 28%, and Africa 21%. This implies that the newly importing countries can confidently expect an increase in asbestos-related disease and death well into the twenty-first century, even if the trade ceased now.

Asbestos↗

PubMed1984

Asbestos catalyzes hydroxyl and superoxide radical generation from hydrogen peroxide.

To understand chemical characteristics of the asbestos minerals which might contribute to tissue damage, the catalytic properties of three different varieties were studied. Using spin trapping techniques it was determined that crocidolite, chrysotile, and amosite asbestos were all able to catalyze the generation of toxic hydroxyl radicals from a normal byproduct of tissue metabolism, hydrogen peroxide. The iron chelator desferroxamine inhibits this reaction, indicating a major role for iron in the catalytic process, and suggesting a possible mechanism by which asbestos toxicity might be reduced.

Asbestos↗

PubMed2003

An asbestos job exposure matrix to characterize fiber type, length, and relative exposure intensity.

The relationship between asbestos exposure and disease has been well documented, although questions persist as to variation in risk by the type and length of fiber. For a series of jobs with potential asbestos exposure, the primary fiber type (e.g., amosite, anthophylite, chrysotile, crocidolite, or tremolite) and fiber length were identified and the relative exposure intensity was estimated. The resulting job exposure matrix may be useful in epidemiological studies where asbestos is an exposure of interest.

Asbestos↗

PubMed1995

The sizes, shapes, and mineralogy of asbestos structures that induce lung tumors or mesothelioma in AF/HAN rats following inhalation.

Data from inhalation studies in which AF/HAN rats were exposed to nine different types of asbestos dusts (in 13 separate experiments) are employed in a statistical analysis to determine if a measure of asbestos exposure (expressed as concentrations of structures with defined sizes, shapes and mineralogy) can be identified that satisfactorily predicts the observed lung tumor or mesothelioma incidence in the experiments. Due to limitations in the characterization of asbestos structures in the original studies, new exposure measures were developed from samples of the original dusts that were re-generated and analyzed by transmission electron microscopy using a direct transfer technique. This analysis provided detailed information on the mineralogy (i.e., chrysotile, amosite, crocidolite or tremolite), type (i.e., fiber, bundle, cluster, or matrix), size (length and width) and complexity (i.e., number of identifiable components of a cluster or matrix) of each individual structure. No univariate measure of exposure was found to provide an adequate description of the lung tumor responses observed among the inhalation studies, although the measure most highly correlated with tumor incidence is the concentration of structures > or = 20 microns in length. Multivariate measures of exposure were identified that do adequately describe the lung tumor responses. Structures contributing to lung tumor risk appear to be long (> or = 5 microns) thin (0.4 microns) fibers and bundles, with a possible contribution by long and very thick (> or = 5 microns) complex clusters and matrices. Potency appears to increase with increasing length, with structures longer than 40 microns being about 500 times more potent than structures between 5 and 40 microns in length. Structures < 5 microns in length do not appear to make any contribution to lung tumor risk. This analysis did not find a difference in the potency of chrysotile and amphibole toward the induction of lung tumors. However, mineralogy appears to be important in the induction of mesothelioma with chrysotile being less potent than amphibole.

Administration, Inhalation↗

PubMed1991

Fibre distribution in the lungs and pleura of subjects with asbestos related diffuse pleural fibrosis.

The lungs from 13 cases of diffuse pleural fibrosis associated with a history of exposure to asbestos were examined. Samples were taken from the visceral pleura and central and subpleural zones of the lungs for histopathological and mineralogical studies. The fibre type, size, and number were estimated for each of these regions by transmission electron microscopy and energy dispersive x ray analysis. Amphibole fibre counts were raised when compared with a non-occupationally exposed group and matched those seen in cases of pleural plaques, mild asbestosis, and mesothelioma. A wide case to case variation of distribution was seen. No significant difference was apparent between central and subpleural zones, whereas low asbestos counts were found in the pleura; these were mainly short chrysotile fibres. Within the lungs more (45%) of the longer (greater than 4 microns) and thinner (less than 0.25 micron) amphibole fibres were retained in keeping with other studies implicating such fibre profiles in the pathogenesis of asbestos related disease.

Aged↗

PubMed1980

Acid and alkaline phosphatase in macrophages of Tenebrio molitor larvae stimulated with asbestos.

The authors studied the activity of acid and alkaline phosphatase in macrophages of Tenebrio molitor larvae stimulated with various types of asbestos: A and B chrysotile, crocidolite, amosite and anthophylite. The activity of the two enzymes increased, as did those of beta-galactosidase and N-acetyl-beta-D-glucosaminidase, two previously assayed enzymes. The increase indicates the toxic action of various types of asbestos and correlates to variations in the mortality curves. The increases of the enzymatic activity and the macrophage response vary with the type of asbestos.

Acid Phosphatase↗

PubMed2002

Cancer incidence among workers in the asbestos-cement producing industry in Norway.

OBJECTIVES: The incidence of cancer among employees of a Norwegian asbestos-cement factory was studied in relation to duration of exposure and time since first exposure. The factory was active in 1942-1968. Most of the asbestos in use was chrysotile, but for technical reasons 8% amphiboles was added. METHODS: For the identification of cancer cases, a cohort of 541 male workers was linked to the Cancer Registry of Norway. The analysis was based on the comparison between the observed and expected number of cancer cases. Standardized incidence ratios (SIR) and 95% confidence intervals (95% CI) were estimated. Period of first employment, duration of employment, and time since first employment were used as indicators of exposure. Poisson regression analysis was used for the internal comparisons. RESULTS: The standardized incidence ratio was 52.5 (95% CI 31.1-83.0) for pleural mesothelioma, on the basis of 18 cases. The highest standardized incidence ratio was found for workers first employed in the earliest production period (SIR 99.0, 95% CI 51.3-173). No peritoneal mesothelioma was found. The standardized incidence ratio for lung cancer was 3.1 (95% CI 2.14.3), but no dose-response effect was observed. The ratio of mesothelioma to lung cancer cases was 1:2. CONCLUSIONS: This study showed a high incidence of mesothelioma and a high ratio of mesothelioma to lung cancer among asbestos-cement workers. The high incidence of mesothelioma was probably due to the fact that a relatively high proportion of amphiboles was used in the production process.

Aged↗

PubMedDate not supplied

[An approach to the classification and assessment of asbestos-containing wastes: description of a survey conducted in an industrial area].

A survey was conducted in a unused textile plant, located in an urban area, where large quantities of solid wastes were stocked. They resulted from the dismantling of the heating system and contained different types of asbestos. The aim of the survey was to classify the wastes according to the criteria established by Italian law (Presidential Decree No. 915, 1982), which requires that "dusts and free fibres" be accounted for when determining the concentration of asbestos in waste. This legislation leaves two main questions open: i) the choice of the analytical method for asbestos determination that should be used to obtain basic information for waste classification; ii) the criteria to be used to define "free fibres" in waste. A general approach to the solution of these issues is offered and applied to the case in question as a possible practical model of environmental control in this specific field.

Asbestos↗

PubMed1984

Fiber size and number in amphibole asbestos-induced mesothelioma.

Numbers and sizes of fibers from the lungs of 10 patients who had an amphibole asbestos-induced malignant pleural mesothelioma were analyzed. Amosite was found in 10 lungs and crocidolite in 9; the average ratio of amosite to crocidolite was approximately 14:1. In the 8 patients who were not long-time asbestos insulators , the mean number of amosite fibers was 2.3 X 10(6) fibers/g dry lung, and of crocidolite fibers, 0.2 X 10(6)/g; these values represent an approximately 250-fold increase over those found in the general population. Crocidolite fibers were significantly narrower than amosite fibers (mean width, 0.13 versus 0.23 mu), were significantly shorter (mean length, 4.0 versus 5.8 mu), and had a significantly higher mean aspect (length to width) ratio (48 versus 34). Aspect ratios in general increased with increasing fiber length and decreasing fiber width, but the highest values were found for thin amosite fibers at about 13 mu in length, and thin crocidolite fibers at 8 or 15-17 mu in length. Comparison with data from other asbestos-exposed populations indicates that mesothelioma can be induced by relatively small numbers of amphibole fibers and also indicates that amosite is an effective mesothelial carcinogen in humans. Comparison of these data with epidemiologic and experimental predictions of carcinogenic size ranges for mesothelioma induction implies that either the carcinogenic size range is much broader than has been claimed (in particular, fibers considerably shorter than 8 mu and broader than 0.05 mu can produce mesothelioma), or, alternately, that extraordinarily small absolute numbers of fibers in certain size ranges can induce tumors in humans.

Aged↗

PubMed1995

In vitro biological effects of clay minerals advised as substitutes for asbestos.

We studied one sample of commercial sepiolite and two samples of commercial vermiculite--clay minerals proposed as replacements for asbestos--and tested in vitro their abilities to activate complement, to lyse erythrocytes, and to elicit the production of reactive oxygen species (ROS) with human polymorphonuclear leukocytes (PMN) or bovine alveolar macrophages (AM); their behavior was compared with that of asbestos fibers obtained from the Union International Contra Cancer (UICC) as reference standards, as well as with kaolinite and illite, main members of the clay mineral family. Since in short-term in vitro tests the biological activity of mineral particles seems especially related to the active sites on their surface, we first measured the specific surface area of each mineral. Sepiolite was unreactive in two of the three tests we used (complement activation and ROS production) and able to lyse a minimal percentage of red blood cells. Vermiculite was shown to be incapable of activating complement, to have a moderate hemolytic activity and a high ability to elicite ROS production, although lower than that of chrysotile. Sepiolite, therefore, might be of more interest than vermiculite, given the low level of biological effects detected during the tests used to compare both clay minerals with asbestos fibres. The ROS production does not seem to require phagocytosis. A high ROS production was observed with kaolinite: this result casts doubt on the ability of pathogenic mineral dusts in vitro to induce a greater release of ROS than nonpathogenic mineral dusts.

Acridines↗