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1.
Cancer Sci ; 111(4): 1180-1192, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32080953

RESUMO

The onset of malignant mesothelioma (MM) is linked to exposure to asbestos fibers. Asbestos fibers are classified as serpentine (chrysotile) or amphibole, which includes the crocidolite, amosite, anthophyllite, tremolite, and actinolite types. Although few studies have been undertaken, anthophyllite has been shown to be associated with mesothelioma, and tremolite, a contaminant in talc and chrysotile, is a risk factor for carcinogenicity. Here, after characterizing the length and width of these fibers by scanning electron microscopy, we explored the cytotoxicity induced by tremolite and anthophyllite in cells from an immortalized human mesothelial cell line (MeT5A), murine macrophages (RAW264.7), and in a rat model. Tremolite and short anthophyllite fibers were phagocytosed and localized to vacuoles, whereas the long anthophyllite fibers were caught on the pseudopod of the MeT5A and Raw 264.7 cells, according to transmission electron microscopy. The results from a 2-day time-lapse study revealed that tremolite was engulfed and damaged the MeT5A and RAW264.7 cells, but anthophyllite was not cytotoxic to these cells. Intraperitoneal injection of tremolite in rats induced diffuse serosal thickening, whereas anthophyllite formed focal fibrosis and granulomas on peritoneal serosal surfaces. Furthermore, the loss of Cdkn2a/2b, which are the most frequently lost foci in human MM, were observed in 8 cases of rat MM (homozygous deletion [5/8] and loss of heterozygosity [3/8]) by array-based comparative genomic hybridization techniques. These results indicate that tremolite initiates mesothelial injury and persistently frustrates phagocytes, causing subsequent peritoneal fibrosis and MM. The possible mechanisms of carcinogenicity based on fiber diameter/length are discussed.


Assuntos
Asbestos/toxicidade , Inibidor de Quinase Dependente de Ciclina p15/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Neoplasias Pulmonares/genética , Mesotelioma/genética , Animais , Amiantos Anfibólicos/toxicidade , Asbesto Crocidolita/toxicidade , Asbestos Serpentinas/toxicidade , Hibridização Genômica Comparativa , Homozigoto , Humanos , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Mesotelioma/induzido quimicamente , Mesotelioma/patologia , Ratos , Fatores de Risco , Deleção de Sequência/genética
2.
Sci Total Environ ; 700: 134622, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31693951

RESUMO

Serpentinitic ultramafic geological environments (SUGEs) contain toxic geogenic contaminants (TGCs). Yet comprehensive reviews on the medical geology of SUGEs are still lacking. The current paper posits that TGCs occur widely in SUGEs, and pose human health risks. The objectives of the review are to: (1) highlight the nature, occurrence and behaviour of TGCs associated with SUGEs; (2) discuss the human intake pathways and health risks of TGCs; (4) identify the key risk factors predisposing human health to TGCs particularly in Africa; and (5) highlight key knowledge gaps and future research directions. TGCs of human health concern in SUGEs include chrysotile asbestos, toxic metals (Fe, Cr, Ni, Mn, Zn, Co), and rare earth elements. Human intake of TGCs occur via inhalation, and ingestion of contaminated drinking water, wild foods, medicinal plants, animal foods, and geophagic earths. Occupational exposure may occur in the mining, milling, sculpturing, engraving, and carving industries. African populations are particularly at high risk due to: (1) widespread consumption of wild foods, medicinal plants, untreated drinking water, and geophagic earths; (2) weak and poorly enforced environmental, occupational, and public health regulations; and (3) lack of human health surveillance systems. Human health risks of chrysotile include asbestosis, cancers, and mesothelioma. Toxic metals are redox active, thus generate reactive oxygen species causing oxidative stress. Dietary intake of iron and geophagy may increase the iron overload among native Africans who are genetically predisposed to such health risks. Synergistic interactions among TGCs particularly chrysotile and toxic metals may have adverse human health effects. The occurrence of SUGEs, coupled with the several risk factors in Africa, provides a unique and ideal setting for investigating the relationships between TGCs and human health risks. A conceptual framework for human health risk assessment and mitigation, and future research direction are highlighted.


Assuntos
Monitoramento Ambiental , Substâncias Perigosas/análise , Medição de Risco , África , Animais , Asbestos Serpentinas , Asbestose , Exposição Ambiental , Geologia , Humanos , Ferro , Neoplasias Pulmonares , Mesotelioma , Metais Pesados , Metais Terras Raras , Mineração
3.
PLoS One ; 14(12): e0225929, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31830070

RESUMO

Endolithic microbial communities survive nutrient and energy deficient conditions while contributing to the weathering of their mineral substrate. This study examined the mineral composition and microbial communities of fully serpentinized weathered rock from 0.1 to 6.5 m depth at a site within the Khalilovsky massif, Orenburg Region, Southern Ural Mountains, Russia. The mineral composition includes a major content of serpentinite family (mostly consisting of lizardite and chrysotile), magnesium hydrocarbonates (hydromagnesite with lesser amounts of hydrotalcite and pyroaurite) concentrated in the upper layers, and clay minerals. We found that the deep-seated weathered serpentinites are chrysotile-type minerals, while the middle and surface serpentinites mostly consist of lizardite and chrysotile types. Microbial community analysis, based on 16S rRNA gene sequencing, showed a similar diversity of phyla throughout the depth profile. The dominant bacterial phyla were the Actinobacteria (of which unclassified genera in the orders Acidimicrobiales and Actinomycetales were most numerous), Chloroflexi (dominated by an uncultured P2-11E order) and the Proteobacteria (predominantly class Betaproteobacteria). Densities of several groups of bacteria were negatively correlated with depth. Occurrence of the orders Actinomycetales, Gaiellales, Solirubrobacterales, Rhizobiales and Burkholderiales were positively correlated with depth. Our findings show that endolithic microbial communities of the Khalilovsky massif have similar diversity to those of serpentine soils and rocks, but are substantially different from those of the aqueous environments of actively serpentinizing systems.


Assuntos
Asbestos Serpentinas/análise , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Microbiota , Minerais/análise , Microbiologia do Solo , Biodiversidade , Biologia Computacional/métodos , Metagenoma , Metagenômica/métodos , Filogenia , RNA Ribossômico 16S/genética , Federação Russa , Análise Espectral
4.
Inhal Toxicol ; 31(8): 325-342, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31690138

RESUMO

Grinding and drilling of chrysotile asbestos-containing brake pads during the 20th century led to release of chrysotile, resulting in varying levels of workplace exposures of mechanics. Despite exposures, excess risk of mesothelioma remains in doubt. Objectives: The toxicity of particulates is primarily derived through a combination of physicochemical properties and dose and as such this study aimed to determine properties of asbestos-containing brake debris (BD) which may influence pathogenicity and potential of mesothelioma. Materials and Methods: Chrysotile-containing brake pads were ground - to reflect occupational activities, aerosolized, and size-fractionated to isolate respirable fractions. Analysis of morphology, biodurability, surface charge, and interactions with macrophages were undertaken. Results: The respirable fraction of BD contained ∼15-17% free chrysotile fibers thereby constituting a small but relevant potential long fiber dose. Acellular biodurability studies showed rapid dissolution and fragmentation of chrysotile fibers that was consistent for pure chrysotile control and BD samples. Conclusions: The long, free, respirable chrysotile fibers were present in BD, yet were of low bio-durability; incubation in artificial lysosomal fluid led to destruction of free fibers.


Assuntos
Poluentes Ocupacionais do Ar/química , Asbestos Serpentinas/química , Macrófagos/efeitos dos fármacos , Automóveis , Humanos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Espécies Reativas de Oxigênio/análise , Células THP-1
5.
Environ Res ; 178: 108723, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31539822

RESUMO

In California, the metamorphic blueschist occurrences within the Franciscan Complex are commonly composed of glaucophane, which can be found with a fibrous habit. Fibrous glaucophane's potential toxicity/pathogenicity has never been determined and it has not been considered by the International Agency for Research on Cancer (IARC) as a potential carcinogen to date. Notwithstanding, outcrops hosting fibrous glaucophane are being excavated today in California for building/construction purposes (see for example the Calaveras Dam Replacement Project - CDRP). Dust generated by these excavation activities may expose workforces and the general population to this potential natural hazard. In this work, the potential toxicity/pathogenicity of fibrous glaucophane has been determined using the fibre potential toxicity index (FPTI). This model has been applied to a representative glaucophane-rich sample collected at San Anselmo, Marin County (CA, USA), characterized using a suite of experimental techniques to determine morphometric, crystal-chemical parameters, surface reactivity, biodurability and related parameters. With respect to the asbestos minerals, the FPTI of fibrous glaucophane is remarkably higher than that of chrysotile, and comparable to that of tremolite, thus supporting the application of the precautionary approach when excavating fibrous glaucophane-rich blueschist rocks. Because fibrous glaucophane can be considered a potential health hazard, just like amphibole asbestos, it should be taken into consideration in the standard procedures for the identification and assessment of minerals fibres in soil and air samples.


Assuntos
Amiantos Anfibólicos/toxicidade , Fibras Minerais/toxicidade , Asbestos , Asbestos Serpentinas , California , Humanos , Testes de Toxicidade , Virulência
6.
Environ Monit Assess ; 191(9): 564, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31414237

RESUMO

The objective of this study was to determine eco-edaphic characteristics and influence of different substrates on mineral characteristics of facultative serpentinophyte. The total concentration of 20 elements Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Se, and Zn in soil samples and aboveground parts of medicinal plant species Teucrium montanum from various calcareous and serpentinite habitats in the territory of Serbia was determined. The concentration of the elements was established by inductively coupled plasma optical emission spectrometry-ICP-OES. The obtained results showed that the quantities of certain elements Al, As, B, Ca, Cd, Cu, K, Li, P, Se, and Zn were detected more in the soil samples from calcareous habitats in comparison to the quantities of other metals Co, Cr, Fe, Mg, Mn, Na, Ni, which were more frequently found in the soil samples from the serpentinite habitats. Analyzed plant samples from calcareous habitats contained higher concentrations of Al, Ca, Li, and Zn as opposed to serpentinite containing higher concentrations of Co, Cr, Fe, Mg, Mn, Na, Ni, and Se. Examined species can accumulate macro- and microelements in different quantities, depending on the substrate type. Differences in the concentration of certain elements in the soil samples and aboveground parts of the T. montanum from calcareous and serpentinite habitats indicate significant phenotypic plasticity of the investigated species as well as the existence of specific serpentinite ecotypes developed by the activity of various edaphic factors.


Assuntos
Asbestos Serpentinas/análise , Carbonato de Cálcio/análise , Solo/química , Teucrium/metabolismo , Ecossistema , Monitoramento Ambiental/métodos , Íons , Metais/análise , Minerais/análise , Sérvia
7.
Crit Rev Toxicol ; 49(5): 430-444, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31380709

RESUMO

Following a previously published (2012) evaluation of the potential health hazards related to the use of asbestos-containing drywall accessory products, additional information regarding asbestos exposures during the use of accessory products, as well as studies of chrysotile asbestos risk as a function of exposure, have been published in the peer-reviewed literature. The purpose of this analysis is to update the original evaluation with this new information. It was previously estimated that a professional drywaller performing joint compound-associated tasks could have a lifetime cumulative chrysotile exposure of 12-26 f/cc-year. Using conservative assumptions regarding airborne asbestos levels during different drywalling tasks, task duration, and job tenure, we found that a range of 4.3-36.3 f/cc-year is a plausible estimate of a career drywaller's cumulative asbestos exposure from historical joint compound use. The estimated range for bystander exposures would be below (sometimes significantly below) this range depending on the frequency and duration of work near drywallers. Further, the estimated drywaller and bystander total fiber exposures were well below a recently published "no-observed adverse effect level, best estimate" for predominately chrysotile exposures of 89-168 f/cc-year for lung cancer and 208-415 f/cc-year for mesothelioma. We also determined that, even if the chrysotile or possibly talc ingredients in the drywall products had contained asbestiform tremolite, the cumulative tremolite exposures would have been well below a recently published tremolite no-effect level of 0.5-2.6 f/cc-year. Based on our calculations, typical drywall work using asbestos-containing drywall accessory products is not expected to increase the risk of asbestos-related lung cancer or mesothelioma. These conclusions are consistent with the lack of epidemiological evidence that drywall work resulted in an increased incidence of asbestos-related disease in the drywall trades.


Assuntos
Asbestos , Materiais de Construção , Exposição Ambiental/análise , Amiantos Anfibólicos , Asbestos Serpentinas , Exposição Ambiental/normas , Exposição Ambiental/estatística & dados numéricos , Humanos , Neoplasias Pulmonares/epidemiologia , Nível de Efeito Adverso não Observado , Medição de Risco
8.
Waste Manag Res ; 37(9): 914-924, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31315552

RESUMO

The asbestos-containing waste management is a public health topic for countries which have used this mineral. Treatment of chrysotile (white asbestos), a phyllosilicate from serpentine, crocidolite (blue asbestos, first results on this kind of asbestos), one of the five asbestos varieties of amphibole family and asbestos-containing waste conversion process is proposed by using hydrothermal treatment in supercritical water. All samples were treated in an Inconel Batch Reactor. The treatment durations range is from 1 to 6 hours, temperatures range is from 400°C to 750°C, mass concentration range is from 0.02 to 170 mg. mL-1 and pressures are higher than 23 MPa. Ultrapure water is used for sample preparation. This ultrapure water is used to monitor mineral leaching on the aqueous phase and to avoid particle cross-contamination. Transmission electron microscopy analyses were carried out to check the presence or not of asbestos phase. According to these analyses, the best conditions of conversion were 1 hour and 0.02 mg. mL-1 for chrysotile, 3 hours and 0.02 mg. mL-1 for crocidolite and 1 hour and 20 mg. mL-1 for asbestos-containing waste, at T = 750°C. Supercritical water conditions were maintained during the whole treatment. The X-ray diffraction showed that the main phases present after treatments were riebeckite and magnetite (crocidolite), forsterite and enstatite (chrysotile), and calcite, spurrite and gehlenite (asbestos-containing waste). Finally, a scanning electron microscopy analysis was performed to monitor morphological fibre change. The elongated structure, partially fragmented, was found in all samples.


Assuntos
Asbesto Crocidolita , Asbestos , Asbestos Serpentinas , Microscopia Eletrônica de Varredura , Difração de Raios X
9.
Inhal Toxicol ; 31(5): 180-191, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31328588

RESUMO

Context: The potency of various mineral fiber types to produce mesothelioma was previously evaluated for numerous cohorts, but the differences in potencies for distinct fiber types have yet to be explained. Objective: To develop an empirical model that would reconstruct mesothelioma potency factors for various types of fiber based on their chemical composition and dimensionality. Methods: Typical chemical composition and dimensionality metrics (aspect ratios) were obtained and combined with mesothelioma potency factors estimated by Hodgson and Darnton method for Quebec chrysotile, South Africa amosite, South Africa and Australian crocidolite, Russian anthophyllite, Libby amphiboles, and Turkey erionite. The forward stepwise log-log regression method was utilized to determine the best combination of input parameters. Results: Mesothelioma potency factors (RM) for selected cohorts were effectively reconstructed utilizing the median aspect ratio of fibers and equivalent fractions of SiO2, total Fe oxides or total equivalent Fe3+ as Fe2O3, and MgO. Modeled potency factors increase as the aspect ratio, SiO2, and total Fe oxide (or Fe2O3) content grow, and as the MgO content diminishes. Correlation coefficients up to 0.999, p < 0.01, were achieved. The models also yield reasonable estimates of mesothelioma potencies for other fiber types, including Bolivian crocidolite, Russian chrysotile, fluoro-edenite, and others. Conclusion: In spite of the empirical approach, the proposed models provide a starting point for targeted studies of mesothelioma mechanisms by elucidating significant contributing physicochemical factors. The models have an exploratory and preliminary character but can potentially be useful to introduce quantitative structure-activity relationship approaches for the toxicology of fibrous minerals.


Assuntos
Neoplasias Pulmonares/induzido quimicamente , Mesotelioma/induzido quimicamente , Fibras Minerais/toxicidade , Modelos Biológicos , Amiantos Anfibólicos/toxicidade , Asbesto Crocidolita/toxicidade , Asbestos Serpentinas/toxicidade , Humanos
11.
Environ Monit Assess ; 191(6): 391, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31123955

RESUMO

Asbestos-cement was manufactured and used in Lebanon since the early 1950s. Corrugated rooftops of asbestos-cement were mostly spread within residential areas throughout the country. These rooftops are subject to weathering factors which are known to increase friability and risk of hazardous fiber release. This study aimed at assessing the asbestos-cement rooftop friability and the possible emerging risks in the urban-industrial city of Chekka, North Lebanon. The evaluation of the asbestos-cement included two field assessment algorithms and a standardized pull-up test. Hazard of fiber emissions was assessed by a pull-up test method, whereas vulnerability was determined by a level of interaction between people and the rooftops. Geographic object-based image analysis was used to map hazard, vulnerability, and risk of asbestos rooftops in the study area. The field algorithms classified most rooftops in a bad state compared with the pull-up test which ranked most of them as good. The X-ray diffraction analysis showed the presence of serpentine and amphibole fibers, except for crocidolite, in some rooftop samples. Hazard, vulnerability, and risk maps of the sampled area showed how hazard potential was amplified by vulnerability of population to possible fiber emission.


Assuntos
Asbestos Serpentinas/análise , Asbestos/análise , Materiais de Construção/análise , Monitoramento Ambiental/métodos , Humanos , Líbano , Medição de Risco/métodos
12.
Environ Sci Pollut Res Int ; 26(18): 18708-18718, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31055741

RESUMO

Chrysotile accounts for some 90% to 95% of all the asbestos used worldwide. Scientific evidences have shown that asbestos (including chrysotile) exposure is associated with increased rates of lung cancer, asbestosis, and mesothelioma. However, molecular mechanisms underlying the toxicity effects of chrysotile are not clear. This study evaluated the oxidative stress in chronic lung toxicity caused by the intratracheal instillation (IT) of four kinds China representative chrysotile once a month for 12 months in Wistar rats. These results indicated that chrysotile exposure led to an obvious increase in lung mass and slowed the growth of body mass. Inflammation and fibrosis were observed by hematoxylin-eosin (HE) staining. Exposure to chrysotile significantly increased the accumulation of reactive oxygen species (ROS) and the level of lipid peroxidation and decreased antioxidant capacity in lung tissues. Furthermore, 1-6-month chrysotile exposure activated heme oxygenase-1 (HO-1) and heat shock protein 70 (HSP70) expression, whereas 12-month exposure caused significant decreases of two-factor expression levels in XK and MN groups when compared to negative control group. Therefore, our results suggested that chronic chrysotile pulmonary injury in Wistar rats is triggered by oxidative damage. Meanwhile, the oxidative damage of MN and XK was stronger than that of SSX and AKS, and the difference of oxidative damage in four chrysotile could have been brought by its properties, morphology, chemical composition, and particle size. With all the above mentioned in view, we hope that the revealed data in the experiment could contribute to the progress of further researches on the toxicity and mechanism of chrysotile.


Assuntos
Asbestos Serpentinas/toxicidade , Lesão Pulmonar/induzido quimicamente , Pulmão/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Asbestos Serpentinas/química , China , Heme Oxigenase-1/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Pulmão/metabolismo , Lesão Pulmonar/metabolismo , Masculino , Tamanho da Partícula , Ratos , Ratos Wistar
13.
Am J Bot ; 106(5): 690-703, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31070790

RESUMO

PREMISE: Adaptation to harsh edaphic substrates has repeatedly led to the evolution of edaphic specialists and generalists. Yet, it is unclear what factors promote specialization versus generalization. Here, we search for habitat use patterns associated with serpentine endemics (specialists) and serpentine tolerators (generalists) to indirectly test the hypothesis that trade-offs associated with serpentine adaptation promote specialization. We predict that (1) endemics have adapted to chemically harsher and more bare serpentine habitats than tolerators, and (2) edaphic endemics show more habitat divergence from their sister species than tolerators do among on- and off-serpentine populations. METHODS: We selected 8 serpentine endemic and 9 serpentine tolerator species representing independent adaptation to serpentine. We characterized soil chemistry and microhabitat bareness from one serpentine taxon of each species and from a paired nonserpentine sister taxon, resulting in 8 endemic and 9 tolerator sister-taxa pairs. RESULTS: We find endemic serpentine taxa occur in serpentine habitats averaging twice as much bare ground as tolerator serpentine taxa and 25% less soil calcium, a limiting macronutrient in serpentine soils. We do not find strong evidence that habitat divergence between sister taxa of endemic pairs is greater than between sister taxa of tolerator pairs. CONCLUSIONS: These results suggest serpentine endemism is associated with adaptation to chemically harsher and more bare serpentine habitats. It may be that this adaptation trades off with competitive ability, which would support the longstanding, but rarely tested, competitive trade-off hypothesis.


Assuntos
Adaptação Biológica , Evolução Biológica , Cálcio/análise , Ecossistema , Magnoliopsida/fisiologia , Solo/química , Asbestos Serpentinas/análise , California
14.
PLoS One ; 14(4): e0214808, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30946771

RESUMO

Workers processing nephrite, antigorite, or talc may be exposed to paragenetic asbestos minerals. An effective screening method for pneumoconiosis in workers exposed to asbestos-contaminated minerals is still lacking. The objective of this study was to assess the diagnostic accuracy of serum and urinary biomarkers for pneumoconiosis in workers exposed to asbestos-contaminated minerals. We conducted a case-control study in a cohort of stone craft workers in Hualien, where asbestos, nephrite, antigorite, and talc are produced. A total of 140 subjects were screened between March 2013 and July 2014. All subjects received a questionnaire survey and a health examination that included a physical examination; chest X-ray; and tests for standard pulmonary function, fractional exhaled nitric oxide, serum soluble mesothelin-related peptide (SMRP), fibulin-3, carcinoembryonic antigen (CEA), and urinary 8-Oxo-2'-deoxyguanosine (8-OHdG)/creatinine. After excluding subjects with uraemia and chronic obstructive pulmonary disease (COPD), we included 48 subjects with pneumoconiosis and 90 control subjects without pneumoconiosis for analysis. In terms of occupational history, 43/48 (90%) case subjects and 68% (61/90) of the control subjects had processed asbestos-contaminated minerals, including nephrite, antigorite, and talc. The case group had decreased pulmonary function in forced vital capacity (FVC), forced expiratory volume in one second, and forced expiratory flow between 25% and 75% of the FVC. The levels of SMRP, fibulin-3, urinary 8-OHdG/creatinine, and CEA were higher in the case group than in the control group. Subjects exposed to nephrite had significantly higher SMRP levels (0.84 ± 0.52 nM) than subjects exposed to other types of minerals (0.60 ± 0.30 nM). A dose-response relationship was observed between the SMRP level and the severity of pneumoconiosis. Machine learning algorithms, including variables of sex, age, SMRP, fibulin-3, CEA, and 8-OHdG/creatinine, can predict pneumoconiosis with high accuracy. The areas under the receiver operating characteristic curves ranged from 0.7 to 1.0. We suggest that SMRP and fibulin-3 could be used as biomarkers of pneumoconiosis in workers exposed to asbestos-contaminated minerals.


Assuntos
Asbestos/efeitos adversos , Exposição Ocupacional , Pneumoconiose/sangue , Pneumoconiose/urina , 8-Hidroxi-2'-Desoxiguanosina/sangue , 8-Hidroxi-2'-Desoxiguanosina/urina , Adulto , Idoso , Asbestos Serpentinas/efeitos adversos , Asbestose/sangue , Asbestose/fisiopatologia , Asbestose/urina , Biomarcadores/sangue , Biomarcadores/urina , Antígeno Carcinoembrionário/sangue , Antígeno Carcinoembrionário/urina , Estudos de Casos e Controles , Estudos de Coortes , Creatinina/sangue , Creatinina/urina , Proteínas da Matriz Extracelular/sangue , Proteínas da Matriz Extracelular/urina , Feminino , Volume Expiratório Forçado , Proteínas Ligadas por GPI/sangue , Proteínas Ligadas por GPI/urina , Humanos , Masculino , Fluxo Máximo Médio Expiratório , Pessoa de Meia-Idade , Minerais/efeitos adversos , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Pneumoconiose/fisiopatologia , Taiwan , Talco/efeitos adversos , Capacidade Vital
15.
Crit Rev Toxicol ; 49(1): 11-35, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30873891

RESUMO

The global use of "asbestos" in various commercial products has led to a wide range and pervasive legacy of disease. One such use of chrysotile asbestos was brake pads and was utilized commonly in automobiles and heavy vehicles. The result of incorporation of chrysotile into brake pads is associated with the exposure of mechanics fitting and servicing vehicles to liberated chrysotile fibers. Despite the proven exposure, the relative risk of malignant mesothelioma (MM) in this occupational population is broadly seen as low. The toxicity of particulates, including fibers such as chrysotile, is driven by a combination of dose and physicochemical properties. As such, it is plausible that chrysotile released from brake pads may have undergone modification, thereby altering the pathogenicity profile. The impact of high sheer stress causing shortening of long fibers, heat modification, binding of resin matrix to the fiber surface on the relative toxicity of brake debris with regards to MM is considered. It is apparent that released chrysotile can undergo significant modification, reducing the long fiber dose although not all modifications may lead to reduced toxicity.


Assuntos
Asbestos Serpentinas/toxicidade , Automóveis , Exposição Ambiental , Mesotelioma/epidemiologia , Humanos , Mesotelioma/induzido quimicamente
16.
ISME J ; 13(7): 1750-1762, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30872803

RESUMO

Hydration of ultramafic rock during the geologic process of serpentinization can generate reduced substrates that microorganisms may use to fuel their carbon and energy metabolisms. However, serpentinizing environments also place multiple constraints on microbial life by generating highly reduced hyperalkaline waters that are limited in dissolved inorganic carbon. To better understand how microbial life persists under these conditions, we performed geochemical measurements on waters from a serpentinizing environment and subjected planktonic microbial cells to metagenomic and physiological analyses. Metabolic potential inferred from metagenomes correlated with fluid type, and genes involved in anaerobic metabolisms were enriched in hyperalkaline waters. The abundance of planktonic cells and their rates of utilization of select single-carbon compounds were lower in hyperalkaline waters than alkaline waters. However, the ratios of substrate assimilation to dissimilation were higher in hyperalkaline waters than alkaline waters, which may represent adaptation to minimize energetic and physiologic stress imposed by highly reducing, carbon-limited conditions. Consistent with this hypothesis, estimated genome sizes and average oxidation states of carbon in inferred proteomes were lower in hyperalkaline waters than in alkaline waters. These data suggest that microorganisms inhabiting serpentinized waters exhibit a unique suite of physiological adaptations that allow for their persistence under these polyextremophilic conditions.


Assuntos
Asbestos Serpentinas/química , Fenômenos Fisiológicos Bacterianos , Sedimentos Geológicos/microbiologia , Adaptação Fisiológica , Anaerobiose , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Carbono/metabolismo , Metagenômica , Omã , Oxirredução , Microbiologia da Água
17.
Ann Glob Health ; 85(1)2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30924615

RESUMO

BACKGROUND: Asbestos consumption in Latin America (LA) amounts to 10% of yearly global production. Little is known about the impact of asbestos exposure in the region. OBJECTIVE: To discuss scientific and socio-economic issues and conflicts of interest and to summarize epidemiological data of asbestos health effects in LA. DISCUSSION: Recent data on chrysotile strengthened the evidence of its carcinogenicity and showed an excessive risk of lung cancer at cumulative exposure levels as low as 1.5 fibre-years/ml. Technology for substitution is available for all asbestos-containing products and ceasing asbestos production and manufacturing will not result in unemployment and loss of income, except for the mining industry. The flawed arguments used by the industry to maintain its market, both to the public and in courtrooms, strongly relies on the lack of local evidence of the ill effects and on the invisibility of asbestos-related diseases in LA, due to the limited number of studies and the exposed workers' difficulty accessing health services. The few epidemiological studies available show clear evidence of clusters of mesothelioma in municipalities with a history of asbestos consumption and a forecasted rise in its incidence in Argentina and Brazil for the next decade. In Brazil, non-governmental organizations of asbestos workers were pivotal to counterbalance misinformation and inequities, ending recently in a Supreme Court decision backing an asbestos ban. In parallel, continuous efforts should be made to stimulate the growth of competent and ethical researchers to convey adequate information to the scientific community and to the general public.


Assuntos
Asbestos Serpentinas/economia , Asbestos Serpentinas/toxicidade , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/etiologia , Mesotelioma/epidemiologia , Exposição Ocupacional/prevenção & controle , Carcinogênese , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Exposição Ambiental/prevenção & controle , Humanos , América Latina/epidemiologia , Mineração , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Saúde Pública
18.
Environ Res ; 171: 550-557, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30763876

RESUMO

BACKGROUND: The mechanisms by which mineral fibers induce adverse effects in vivo are still not well understood. The mechanisms of fiber dissolution in the lungs and subsequent release of metals in the extracellular/intracellular environment must be taken into account. AIM: For the first time, the kinetics of release of metals during the acellular in vitro dissolution of chrysotile, crocidolite and fibrous erionite were determined. METHODS: In vitro acellular dissolution of chrysotile, crocidolite, and fibrous erionite-Na was conducted using a solution mimicking the phagolysosome environment active during the phagocytosis process (pH=4.5, at 37 °C). The kinetics of release of a representative selection of metals were determined over a period of three months. RESULTS: Despite the fact that the difference in Fe content between chrysotile and crocidolite is one order of magnitude, the much faster dissolution rate of chrysotile compared to crocidolite prompts greater release of available active surface Fe in the first weeks of the dissolution experiment and comparable amounts after 90 d. Such active iron may promote the formation of toxic hydroxyl radicals. The fast release of metals like Cr, Ni and Mn from chrysotile is also a source of concern whereas the release of V in solution is negligible. CONCLUSION: Because chrysotile undergoes fast dissolution with respect to crocidolite and fibrous erionite, it behaves like a carrier that releases its metals' cargo in the lung environment, mimicking the phenomenon that explains the toxicity of nanoparticles. Hence, the toxicity paradigm of a non biodurable fiber like chrysotile should also take into account the release of toxic metals in the intracellular/extracellular medium during the rapid dissolution process.


Assuntos
Asbesto Crocidolita , Asbestos Serpentinas , Metais , Modelos Químicos , Asbestos , Solubilidade , Zeolitas
19.
Cancer Sci ; 110(3): 1076-1084, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30618090

RESUMO

Occupational asbestos exposure occurs in many workplaces and is a well-known cause of mesothelioma and lung cancer. However, the association between nonoccupational asbestos exposure and those diseases is not clearly described. The aim of this study was to investigate cause-specific mortality among the residents of Amagasaki, a city in Japan with many asbestos factories, and evaluate the potential excess mortality due to established and suspected asbestos-related diseases. The study population consisted of 143 929 residents in Amagasaki City before 1975 until 2002, aged 40 years or older on January 1, 2002. Follow-up was carried out from 2002 to 2015. Standardized mortality ratio (SMR) with its 95% confidence interval (CI) was calculated by sex, using the mortality rate of the Japanese population as reference. A total of 38 546 deaths (including 303 from mesothelioma and 2683 from lung cancer) were observed. The SMRs in the long-term residents' cohort were as follows: death due to all causes, 1.12 (95% CI, 1.10-1.13) in men and 1.07 (95% CI, 1.06-1.09) in women; lung cancer, 1.28 (95% CI, 1.23-1.34) in men and 1.23 (95% CI, 1.14-1.32) in women; and mesothelioma, 6.75 (95% CI, 5.83-7.78) in men and 14.99 (95% CI, 12.34-18.06) in women. These SMRs were significantly higher than expected. The increased SMR of mesothelioma suggests the impact of occupational asbestos exposure among men and nonoccupational asbestos exposure among women in the long-term residents' cohort. In addition, the high level of excess mortality from mesothelioma has persisted, despite the mixture of crocidolite and chrysotile no longer being used for three or four decades.


Assuntos
Asbestos/efeitos adversos , Doenças Profissionais/epidemiologia , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Asbesto Crocidolita/efeitos adversos , Asbestos Serpentinas/efeitos adversos , Estudos de Coortes , Humanos , Japão/epidemiologia , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/etiologia , Masculino , Mesotelioma/epidemiologia , Mesotelioma/etiologia , Pessoa de Meia-Idade , Neoplasias Pleurais/epidemiologia , Neoplasias Pleurais/etiologia
20.
Int J Mol Sci ; 20(1)2019 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-30609805

RESUMO

Asbestos exposure increases the risk of asbestosis and malignant mesothelioma (MM). Both fibrosis and cancer have been correlated with the Epithelial to Mesenchymal Transition (EMT)-an event involved in fibrotic development and cancer progression. During EMT, epithelial cells acquire a mesenchymal phenotype by modulating some proteins. Different factors can induce EMT, but Transforming Growth Factor ß (TGF-ß) plays a crucial role in promoting EMT. In this work, we verified if EMT could be associated with MM development. We explored EMT in human mesothelial cells (MeT-5A) exposed to chrysotile asbestos: we demonstrated that asbestos induces EMT in MeT-5A cells by downregulating epithelial markers E-cadherin, ß-catenin, and occludin, and contemporarily, by upregulating mesenchymal markers fibronectin, α-SMA, and vimentin, thus promoting EMT. In these cells, this mechanism is mediated by increased TGF-ß secretion, which in turn downregulates E-cadherin and increases fibronectin. These events are reverted in the presence of TGF-ß antibody, via a Small Mother Against Decapentaplegic (SMAD)-dependent pathway and its downstream effectors, such as Zinc finger protein SNAI1 (SNAIL-1), Twist-related protein (Twist), and Zinc Finger E-Box Binding Homeobox 1 (ZEB-1), which downregulate the E-cadherin gene. Since SNAIL-1, Twist, and ZEB-1 have been shown to be overexpressed in MM, these genes could be considered possible predictive or diagnostic markers of MM development.


Assuntos
Asbestos Serpentinas/toxicidade , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Anticorpos/imunologia , Caderinas/genética , Caderinas/metabolismo , Linhagem Celular , Regulação para Baixo/efeitos dos fármacos , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Fibronectinas/genética , Fibronectinas/metabolismo , Humanos , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Metaloproteinase 2 da Matriz/genética , Metaloproteinase 2 da Matriz/metabolismo , Mesotelioma/induzido quimicamente , Mesotelioma/patologia , Proteínas Smad/genética , Proteínas Smad/metabolismo , Fatores de Transcrição da Família Snail/genética , Fatores de Transcrição da Família Snail/metabolismo , Fator de Crescimento Transformador beta/imunologia , Regulação para Cima/efeitos dos fármacos , Vimentina/genética , Vimentina/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , beta Catenina/genética , beta Catenina/metabolismo
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