[Dose and effect biomarkers in the diagnosis of asbestos-related diseases and health surveillance of exposed workers]. / Gli indicatori biologici di dose ed effetto nella diagnostica delle patologie asbesto-correlate e nella sorveglianza sanitaria degli ex-esposti.

The aim of the study was to assess the reliability of the indicators of dose and effect in the health monitoring of asbestos exposed workers. In 49 cases out of 158 studied workers (31%) asbestos-related diseases were diagnosed following ATS criteria (2004). Using nonparametric statistical methods (permutation tests) 6 variables were analyzed with respect to asbestos-related diseases and working sectors, demonstrating a difference in the concentration of amphiboles (p < 0.01), greater in patients with asbestosis and workers involved in asbestos removal from railway carriages. There was not a correlation between mesothelin and amphiboles, chrysotile and total fibers concentrations (Spearman test).

Measurement of asbestos fibre concentrations in fluid of repeated bro-choalveolar lavages of exposed workers.

OBJECTIVES: The aim of this study was to assess the reliability of asbestos fibre concentration in bronchoalveolar lavage fluid (BALF) by carrying out the mineralogical analysis of BALF at different times in the same patient and comparing the results. METHODS: Twenty two patients underwent diagnostic fibreoptic bronchoscopy twice: the first was to assess the past asbestos exposure and the second for different clinical reasons. Mineralogical analysis of BALF was carried out. RESULTS: In 16 patients (72.7%), a reduction of concentration in BALF of all asbestos fibres was observed. The concentrations of both chrysotile and amphiboles in the first bronchoalveolar lavage (BAL) were related to their concentrations in the second BAL and the observed differences were not statistically significant. A significant decrease in asbestos body concentration between the first and the second BAL was found (Wilcoxon test, P < 0.01). CONCLUSIONS: The reliability of the fibre concentration in BALF as a marker of past asbestos exposure seems quite good. In most cases, it allows us to distinguish workers in different classes of exposure and gives useful information on the pattern of exposure. Uncertainties related in general to lung residues and in particular to mineralogical analysis of BALF (mainly due to the high coefficient of variation (CV) at low fibre concentrations and the results of the statistical analysis on total fibres) suggest that this biomarker is more likely suitable for a qualitative/categorical approach to exposure assessment than a quantitative one.

[Estimate of the previous exposure to asbestos through mineralogical examination of the bronchoalveolar lavage (BAL) fluid in a population working in a sugar industry]. / Stima della pregressa esposizione ad asbesto mediante esame mineralogico del liquido di lavaggio broncoalveolare in una popolazione di lavoratori di uno zuccherificio.

In this study the past professional exposure and the health state of sugar refinery workers in Arezzo (Italy) are reviewed. The medical examinations, confirmed by chest CT, showed asbestos pleural thickening and one asbestosis case. Mineralogical analysis of bronchoalveolar lavage fluid (BALF) was carried out in this population to measure the pulmonary burden. Total fiber's concentration was not different in either subjects with or without asbestos-related disease. Notably, comparison between total fiber's concentration in sugar refinery workers and subjects employed in other industries, revealed a lower professional exposure of the former with respect to shipyard workers and electric plants. In other groups of Italian sugar refinery workers, a concentration of asbestos fibers higher than in the studied population was found. Thus, the study highlights the necessity to develop standardized methodologies to carry out health intervention programmes in workers previously exposed to asbestos.

[Assessment of asbestos exposure via mineralogical analysis of bronchoalveolar lavage fluid]. / Stima dell'esposizione ad asbesto mediante analisi mineralogica del liquido di lavaggio broncoalveolare.

BACKGROUND: Mineralogical analysis of bronchoalveolar lavage fluid (BALF) by electron microscopy could be the most suitable method for assessing asbestos exposure. However, it has been claimed that there is not a standardized or systematic approach to the subject of mineralogical analysis. OBJECTIVES: The aim of the study was to evaluate mineralogical analysis of BALF by transmission electron microscopy (TEM) as biomarker of asbestos fibre load. METHODS: BALF was examined in 193 exposed workers (189 men and 4 women) and in 84 patients (65 men and 19 women) who underwent diagnostic fibreoptic bronchoscopy for various clinical purposes. Asbestos bodies (AB) in BALF were counted with a phase contrast microscope, while fibres were counted and analysed by TEM. RESULTS: Fibre counting by TEM showed a significant difference in the two populations (two tailed Mann-Whitney U test, p=0.0044), since it was positive in all exposed subjects. Only 75.1% of the exposed population was positive for asbestos bodies (AB). Subjects who had been exposed over a long time period had higher concentrations of fibres than subjects who had been exposed more recently probably because of higher exposure in the past. CONCLUSIONS: The study confirms the results of a previous study on a limited number of subjects. Fibre concentrations in BALF can be considered as a reliable biomarker of past asbestos exposure even after many years after cessation of exposure.

Asbestos exposure assessment by mineralogical analysis of bronchoalveolar lavage fluid.

Mineralogical analysis of bronchoalveolar lavage fluid (BALF) by electron microscopy can represent the most suitable method for assessing asbestos exposure. However, it has been claimed that no standardized or systematic approach to the subject of mineralogical analysis exists. This study aimed to evaluate BALF mineralogical analysis by transmission electron microscopy as biomarker of asbestos fiber load. BALF was examined in 108 exposed workers and 57 patients who underwent diagnostic fiberoptic bronchoscopy for various clinical purposes. Asbestos bodies in BALF were counted with a phase-contrast microscope. Fibers were counted and analyzed by transmission electron microscopy, which showed a significant difference between the two populations and positive results for all exposed subjects. Only 82.2% of the exposed population tested positive for asbestos bodies. Subjects with long-term exposure had higher concentrations of fibers than did those with more recent exposure, probably because of the higher workplace exposure levels in the past. The results of the study confirm that fiber concentration in BALF can be considered as a reliable biomarker of past asbestos exposure, even many years after the end of exposure.

[Reactive oxygen species produced by the addition of sepiolite and vermiculite (expanded or not) to suspensions of human polymorphonuclear phagocytes and bovine alveolar macrophages]. / Specie reattive dell'ossigeno indotte dall'addizione di sepiolite e vermiculite (espansa e non) a sospensioni di fagociti, polimorfonucleati umani e macrofagi alveolari bovini.

We have studied a sample of commercial sepiolite and two samples of commercial vermiculite, which are clay minerals advised to replace asbestos. We have in vitro tested their abilities to produce reacting oxygen species (ROS) after they have been added to suspension of human polymorphonuclear leukocytes and bovine alveolar macrophages. The behaviour of sepiolite and vermiculite have been compared with those of asbestos fibres given by Unione Internationale contre le Cancer (UICC) and with kaolin and illite. Sepiolite was not able to induce ROS production, while vermiculite was able to induce a relevant ROS generation, even if the values were always lower than that obtained from chrysotile. Kaolin was able to generate a high ROS production.

Solubilization of lead from crystal dust in protein solution (pseudointerstitial fluid) and gastric juice.

Since several workers engaged in polishing and engraving crystal articles were found to have higher than average blood levels of lead (560 micrograms/liter, range 80-560 micrograms/liter), we investigated the hypothesis that crystal dust releases lead in the human body. To test the hypothesis, two types of crystal polishing dusts, having different lead contents, were mixed with human serum diluted 1:3 (pseudointerstitial fluid), gastric juice, and phosphate buffer at pH 9. After 14 days of contact, the diluted serum had extracted 0.620% of the lead in the crystal dust (particle size < 20 microns) containing 25.2% lead and 0.425% of that containing 19.9% lead. After 48 hr in gastric juice, 0.235 and 0.556% of the lead was extracted from crystal dusts (unsieved crystal dusts) containing 25.2 and 19.9% lead, respectively. After 28 days in alkaline solution, 0.358 and 0.304% of the lead was extracted respectively from the same two crystal dusts (unsieved crystal dusts).

Respiratory disease as a result of talc inhalation.

Three cases of respiratory disease in workers with occupational exposure to talc containing asbestos fibers are reported. Standard chest roentgenographs, high-resolution computed tomography, respiratory function tests, morphologic study of bronchoalveolar lavage fluid (BAL), light microscopic examination, and mineralogical analysis by transmission electron microscopy (TEM) of BAL was performed. All subjects showed bilateral pleural plaques, and in two subjects the study of BAL revealed lymphocytic alveolitis with an increased T4/T8 ratio. Mineralogical analysis of BAL detected asbestos-fiber concentrations of 510, 2039, and 3392 fibers/mL and many asbestos bodies. In one patient, mineralogical analysis of lung tissue was also performed; a concentration of 3,659,000 fibers/g dry tissue was found. Simultaneously, we performed a mineralogical study of 12 commercial talc samples, including those used by the patients during the last phase of their working lives. TEM revealed asbestos fibers in five samples. Two subjects used two of these talc powders. The study presented here confirms the need to perform all relevant clinical tests together with the study of BAL and mineralogical analysis of the materials to which the patients are or were exposed to determine occupational exposure to fibers, including those associated with talc, which are often misidentified.

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.