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1.
Int J Mol Sci ; 20(23)2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31801235

RESUMO

Fiber-reinforced composite (FRC) retainers are an aesthetic alternative to conventional Stainless Steel splints. They are generally used with a full bonded technique, but some studies demonstrated that they could be managed with a spot bonding technique to significantly decrease their rigidity. In order to propose this FRC spot bonding technique for clinical use, the aim of this study was to evaluate mechanical properties and surface wear of fibers left uncovered. Tests were made by simulating tooth brushing, comparing FRC spot bonding technique splints with stainless steel and FRC traditional technique splints. Specimens were tested both at 0.1 mm of deflection and at maximum load, showing higher values of rigidity for the FRC full bonded technique. After tooth brushing, no significant reduction in values at 0.1 mm deflection was reported, while we found a similar reduction in these values for the Stainless Steel and FRC spot bonding technique at maximum load, and no significant variation for the FRC full bonded technique. SEM images after tooth brushing showed wear for FRC fibers left uncovered, while no relevant wear signs in metal and conventional FRC fibers were noticed. Results showed that FRC spot bonding technique has advantages in mechanical properties when compared to the FRC traditional full bonding technique, also after tooth brushing. However, the surface wear after tooth brushing in the FRC spot bonding technique is considerable and other tests must be performed before promoting this technique for routine clinical use.


Assuntos
Resinas Compostas/análise , Materiais Dentários/análise , Fibras Minerais/análise , Aço Inoxidável/análise , Resinas Compostas/síntese química , Colagem Dentária/métodos , Materiais Dentários/química , Humanos , Teste de Materiais/métodos , Estresse Mecânico , Propriedades de Superfície
2.
Artigo em Inglês | MEDLINE | ID: mdl-30970535

RESUMO

A new method was developed to analyze the surface count of fibers in a variety of environments. The method entails sampling surfaces with the help of suction to a filter cassette holder containing a cellulose filter. The filters were collapsed using microwave digestion in dilute acid, and the fibers filtered to polycarbonate filters, gilded, and analyzed by scanning electron microscopy (SEM). The method was compared to traditional gel tape sampling as described in International Standards Organization (ISO) standard 16000-27, following analysis with phase contrast microscopy. The methods were compared in industrial environments and in office-type environments, with the concentration range studied spanning from 0.1 to 100,000 fibers/cm². The methods yielded similar results (p < 0.05) in concentrations from 100 to 10,000 cfu/cm², while the filter cassette method gave systematically higher results in high concentrations (>10,000 cfu/cm²) as well as in all office-type environments studied, where the fiber count ranged from 0.1 to 20 fibers/cm². Consequently, we recommend using the new method in working environments where the surface count is more than 100 fibers/cm², as well as in office-type environments where the fiber count is below 10 fibers/cm². It should be noted, however, that a similar limit of quantitation as with the gel tape method (0.1 fibers/cm²) requires sampling a minimum area of 100 × 100 cm² with the fiber cassette method. Using the filter cassette method will require new guide values to be formed for office-type environments, since the results are higher than with the gel tape method. Alternatively, if present guide values or limit values are to be used with the filter cassette method, conventions as to which fiber sizes to count should be set, since SEM analysis in any case will allow for including a larger size range than phase contrast microscopy (PM). We, however, recommend against such an approach, since fibers less than 1 µm in width may not be less harmful by inhalation than larger fibers.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Vidro/análise , Microscopia Eletrônica de Varredura/métodos , Fibras Minerais/análise , Exposição Ocupacional/análise , Adulto , Filtros de Ar , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Propriedades de Superfície
3.
Free Radic Biol Med ; 133: 21-37, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30071299

RESUMO

Iron and its role as soul of life on Earth is addressed in this review as iron is one of the most abundant elements of our universe, forms the core of our planet and that of telluric (i.e., Earth-like) planets, is a major element of the Earth's crust and is hosted in an endless number of mineral phases, both crystalline and amorphous. To study iron at an atomic level inside the bulk of mineral phases or at its surface, where it is more reactive, both spectroscopy and diffraction experimental methods can be used, taking advantage of nearly the whole spectrum of electromagnetic waves. These methods can be successfully combined to microscopy to simultaneously provide chemical (e.g. iron mapping) and morphological information on mineral particles, and shed light on the interaction of mineral surfaces with organic matter. This review describes the crystal chemistry of iron-bearing minerals of importance for the environment and human health, with special attention to iron in toxic minerals, and the experimental methods used for their study. Special attention is devoted to the Fenton-like chain reaction involving Fe2+ in the formation of highly reactive hydroxyl radicals. The final part of this review deals with release and adsorption of iron in biological fluids, coordinative and oxidative state of iron and in vitro reactivity. To disclose the very mechanisms of carcinogenesis induced by iron-bearing toxic mineral particles, crystal chemistry and surface chemistry are fundamental for a multidisciplinary approach which should involve geo-bio-scientists, toxicologists and medical doctors.


Assuntos
Radical Hidroxila/química , Ferro/química , Fibras Minerais/análise , Minerais/química , Carcinogênese/efeitos dos fármacos , Humanos , Microscopia Eletrônica de Transmissão , Oxirredução/efeitos dos fármacos , Análise Espectral
5.
Toxicol Appl Pharmacol ; 361: 36-46, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-30134140

RESUMO

The length distributions of single fibrils of Coalinga, UICC-B and wet dispersed chrysotile were measured by transmission electron microscopy (TEM). It was found that the distributions significantly diverged above approximately 10 µm (µm) in length, corresponding to differences in published results of animal experiments. This result is in contrast to published data in which counting of an insufficient number of fibers resulted in an erroneous conclusion that the length distribution of Coalinga chrysotile fibrils was indistinguishable from those of other sources of chrysotile. The size distributions of the respirable particle size fractions from acknowledged tremolite asbestos samples were found to be dominated by elongate particles longer than 5 µm that are within the dimensional range of non-asbestiform amphiboles. Prior studies have shown that these elongate particles obscure a correlation between a specific size range of particles and results of animal implantation studies that used tremolite of various morphologies. In the prior studies, a reference protocol was developed from four crushed non-asbestiform amphiboles to differentiate the size range of amphibole particles that correlates with the mesothelioma frequencies observed in the animal studies. In the work reported here, this correlation was tested with TEM analyses of amphiboles from Libby, MT, Sparta, NJ and Homestake mine, Lead, SD, which represent known environmental/occupational situations. Further TEM analyses of the tremolite samples used in the original animal implantation studies have also shown that the numbers of elongate tremolite particles with lengths ≤5 µm implanted into the animals are not correlated with the observed mesothelioma frequencies.


Assuntos
Fibras Minerais/análise , Minerais/análise , Material Particulado/análise , Animais , Amiantos Anfibólicos/análise , Asbestos Serpentinas/análise , Asbestos Serpentinas/toxicidade , Humanos , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/epidemiologia , Mesotelioma/induzido quimicamente , Mesotelioma/epidemiologia , Microscopia Eletrônica de Transmissão , Fibras Minerais/toxicidade , Minerais/toxicidade , Exposição Ocupacional , Tamanho da Partícula , Material Particulado/toxicidade
6.
Toxicol Appl Pharmacol ; 361: 14-17, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29959999

RESUMO

Asbestos mineral fibers have been associated with the development of a variety of diseases in humans and experimental animals, including asbestosis, lung cancer, and mesothelioma. Asbestos includes several mineral types divided into two mineral groups, serpentine and amphibole forms. Chrysotile is the serpentine mineral classified as asbestos, whereas the amphiboles include amosite, crocidolite, tremolite, actinolite and anthophyllite. There are a number of mineral fibers that occur with asbestiform morphology and that have been associated with various asbestos-induced diseases. These include the Libby amphiboles (associated with a vermiculite mine northwest of Libby, MT), erionite (in Turkey and North America), fluoro-edenite (in Sicily), and perhaps balangeroite (in Italy). In addition, each of the asbestos minerals occurs in a non-fibrous form, and these may occur as cleavage fragments that satisfy the definition for a fiber, i.e., particles with an aspect ratio of at least 3:1 and roughly parallel sides. Cleavage fragments of non-asbestiform minerals have not been associated with asbestos-induced diseases nor are these minerals regulated by the Occupational Safety and Health Administration. Finally, there are a number of other mineral species which can occur in human lung samples that satisfy the definition for a fiber as given above. These similarly have not been associated with asbestos-induced diseases. All of these various minerals satisfying the definition for a fiber can be referred to as elongated mineral particles (EMP). It is the purpose of this presentation to discuss the role of scanning electron microscopy (SEM) equipped with an energy dispersive x-ray analyzer (EDXA) in the detection and classification of EMP in human lung samples.


Assuntos
Asbestos/análise , Pulmão/química , Minerais/análise , Material Particulado/análise , Poluentes Ocupacionais do Ar , Humanos , Neoplasias Pulmonares , Mesotelioma , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Fibras Minerais/análise , Tamanho da Partícula
7.
Macromol Biosci ; 18(7): e1800046, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29896921

RESUMO

Biocomposites, i.e., materials consisting of metabolically active microorganisms embedded in a synthetic extracellular matrix, may find applications as highly specific catalysts in bioproduction and bioremediation. 3D constructs based on fibrous biocomposites, so-called "artificial biofilms," are of particular interest in this context. The inability to produce biocomposite fibers of sufficient mechanical strength for processing into bioactive fabrics has so far hindered progress in the area. Herein a method is proposed for the direct wet spinning of microfibers suitable for weaving and knitting. Metabolically active bacteria (either Shewanella oneidensis or Nitrobacter winogradskyi (N. winogradskyi)) are embedded in these fibers, using poly(vinyl alcohol) as matrix. The produced microfibers have a partially crystalline structure and are stable in water without further treatment, such as coating. In a first application, their potential for nitrite removal (N. winogradskyi) is demonstrated, a typical challenge in potable water treatment.


Assuntos
Fibras Minerais/análise , Nitritos/isolamento & purificação , Nitrobacter/química , Shewanella/química , Têxteis/análise , Poluentes da Água/isolamento & purificação , Biodegradação Ambiental , Biofilmes/crescimento & desenvolvimento , Água Potável/química , Humanos , Teste de Materiais , Membranas Artificiais , Nitrobacter/metabolismo , Álcool de Polivinil/química , Shewanella/metabolismo
8.
Molecules ; 23(7)2018 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-29937521

RESUMO

Aerogel materials are recognized as promising candidates for the thermal insulator and have achieved great successes for the aerospace applications. However, the harsh environment on the exoplanet, especially for the tremendous temperature difference, tends to affect the tenuous skeleton and performances of the aerogels. In this paper, an evaluation method was proposed to simulate the environment of exoplanet and study the influence on the fiber-reinforced silica aerogels with different supercritical point drying (SPD) technology. Thermal conductivity, mechanical property and the microstructure were characterized for understanding the thermal failure mechanism. It was found that structure and thermal property were significantly influenced by the adsorbed water in the aerogels under the thermal shocks. The thermal conductivity of CO2-SPD aerogel increased 35.5% after the first shock and kept in a high value, while that of the ethanol-SPD aerogel increased only 19.5% and kept in a relatively low value. Pore size distribution results showed that after the first shock the peak pore size of the CO2-SPD aerogel increased from 18 nm to 25 nm due to the shrinkage of the skeleton, while the peak pore size of the ethanol-SPD aerogel kept at ~9 nm probably induced by the spring-back effect. An 80 °C treatment under vacuum was demonstrated to be an effective way for retaining the good performance of ethanol-SPD aerogels under the thermal shock. The thermal conductivity increases of the ethanol-SPD aerogels after 5 shocks decreased from ~30 to ~0% via vacuum drying, while the increase of the CO2-SPD aerogels via the same treatments remains ~28%. The high-strain hardening and low-strain soften behaviors further demonstrated the skeleton shrinkage of the CO2-SPD aerogel.


Assuntos
Materiais de Construção/análise , Fibras Minerais/análise , Nitrogênio/química , Dióxido de Silício/química , Voo Espacial/instrumentação , Ar/análise , Dióxido de Carbono/química , Temperatura Baixa , Géis , Humanos , Interações Hidrofóbicas e Hidrofílicas , Porosidade , Condutividade Térmica
9.
Sci Rep ; 8(1): 7071, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29728675

RESUMO

The study of the mechanisms by which mineral fibres promote adverse effects in both animals and humans is a hot topic of multidisciplinary research with many aspects that still need to be elucidated. Besides length and diameter, a key parameter that determines the toxicity/pathogenicity of a fibre is biopersistence, one component of which is biodurability. In this paper, biodurability of mineral fibres of social and economic importance (chrysotile, amphibole asbestos and fibrous erionite) has been determined for the first time in a systematic comparative way from in vitro acellular dissolution experiments. Dissolution was possible using the Gamble solution as simulated lung fluid (pH = 4 and at body temperature) so to reproduce the macrophage phagolysosome environment. The investigated mineral fibres display very different dissolution rates. For a 0.25 µm thick fibre, the calculated dissolution time of chrysotile is in the range 94-177 days, very short if compared to that of amphibole fibres (49-245 years), and fibrous erionite (181 years). Diffraction and SEM data on the dissolution products evidence that chrysotile rapidly undergoes amorphization with the formation of a nanophasic silica-rich fibrous metastable pseudomorph as first dissolution step whereas amphibole asbestos and fibrous erionite show minor signs of dissolution even after 9-12 months.


Assuntos
Fibras Minerais/análise , Cinética , Microscopia Eletrônica de Varredura , Solubilidade , Difração de Raios X
10.
Toxicol Appl Pharmacol ; 361: 174-184, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-29705294

RESUMO

Most fiber length distributions fit a log-normal distribution with their being many more shorter fibers present as compared to the longer fibers. As the longer fibers have been suggested to be more important for possible pathogenesis giving equal weight to all fiber lengths when sizing fibers will under sample the longer fibers. The methods described here, are based upon the optimization of fiber counting/sizing rules over a number years of experience and have been developed to provide a stable estimate of the mean number of particles and fibers present in the size ranges: particles, fibers < 5 µm; 5-20 µm; and >20 µm. These methods were first applied using TEM, however, with the development of high resolution SEM, it was found that higher reproducibility could be obtained with SEM.


Assuntos
Fibras Minerais/análise , Aerossóis , Poluentes Ocupacionais do Ar/análise , Animais , Asbestos Serpentinas/análise , Diafragma/patologia , Pulmão/patologia , Linfonodos/patologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Ratos , Reprodutibilidade dos Testes
11.
J Occup Environ Hyg ; 15(6): 466-473, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29580193

RESUMO

Chrysotile asbestos fibers were added to roofing products, including roof cement, for several decades. The fibers were described as "encapsulated" and therefore incapable of being released, an assertion that is disproved by the study reported herein. Three test panels of roof cement from the original container were exposed to ambient weathering in 2015 and 2016. Two panels were then sampled using the ASTM D5755 microvacuum method. Sampling revealed a light brown sub-layer under the dark brown surface layer, both of which crumbled and became friable during sampling. Analysis of the microvacuum samples with transmission electron microscopy showed that the material on the 2 panels contained 4,432,000 and 3,320,000 asbestos structures per cm² with nearly all of the structures consisting of fibers less than 5 µm long. Energy dispersive spectrometry determined that none of the fibers reported were coated with asphalt. The presence of free fibers was confirmed by direct examination of the surfaces of the panels and of dust released from handling the panels via scanning electron microscopy. This study confirmed the releasability of uncoated asbestos fibers from dried roof cement that was indicated in 2 previous studies published in 2007 and 2010. These results suggest that the finding of the Fifth Circuit Court in 1997 that uncoated airborne asbestos fibers cannot be released from roof cement, and therefore do not present a potential exposure by inhalation, was erroneous in retrospect. The exemption of roof cement from regulation under the Occupational Safety and Health Administration Construction Industry Standard for asbestos by the Court should not be relied on by employers of workers who remove weathered asbestos-containing roof cement, and precautions should be taken against exposure to airborne asbestos fibers during this work.


Assuntos
Asbestos Serpentinas/análise , Materiais de Construção/análise , Asbestos Serpentinas/química , Poeira/análise , Hidrocarbonetos/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Fibras Minerais/análise , Tempo (Meteorologia)
12.
Int J Environ Health Res ; 28(2): 134-146, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29564927

RESUMO

Ophiolitic rocks cropping on Calabria territory, southern Italy, can hold asbestiform minerals potentially harmful for human health. The aim of this work was to detect the fibrous phases of ophiolites along the Coastal Chain of northern Calabria and southern part of the Sila massif. Above 220 massive samples were collected in the study areas and analyzed using optical and electron microscopy, X-ray diffractometry, and Fourier transform infra-red spectrometry. The main fibrous constituent belonged to tremolite-actinolite series followed by fibrous antigorite that becomes more abundant in the samples collected in Reventino Mount surroundings. Results highlighted that serpentinites samples mainly consisted of antigorite and minor chrysotile. Samples collected along the coastal chain of northern Calabria did not hold fibrous materials. The results will be useful for Italian natural occurrences of asbestos (NOA) mapping in order to avoid an unintentional exposition by human activity or weathering processes.


Assuntos
Amiantos Anfibólicos/análise , Asbestos Serpentinas/análise , Itália , Microscopia Eletrônica , Fibras Minerais/análise , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
13.
J Occup Environ Hyg ; 15(4): 305-310, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29341858

RESUMO

Refractory ceramic fibers (RCF) have been extensively used for insulation in condensing boilers. The aim of this study was to evaluate the respiratory exposure to these fibers among maintenance heating technicians. We first created a working group (Carsat Brittany and Finistère Occupational Health Services) and carried out a sampling strategy. Atmospheric measurements were done during work tasks, and filters were analyzed by phase contrast microscopy (PCM) and scanning electron microscopy (SEM) in French approved laboratories. Four companies were included for a total of 15 days of work. During those 15 workdays, 12 SEM and 21 PCM samples were taken and analyzed. The phase contrast microscopy and SEM average results were 0.04 and 0.004 fibers/cm3, respectively. In conclusion, the study confirms heating technician RCF respiratory exposure during maintenance work for both condensation gas boilers and atmospheric boilers. Collective and individual prevention measures should be implemented along with appropriate medical follow-up.


Assuntos
Cerâmica/análise , Exposição por Inalação/análise , Exposição Ocupacional/análise , Material Particulado/análise , Poluentes Ocupacionais do Ar/análise , França , Calefação , Humanos , Microscopia Eletrônica de Varredura , Microscopia de Contraste de Fase , Fibras Minerais/análise , Equipamento de Proteção Individual/estatística & dados numéricos
14.
Int J Biol Macromol ; 106: 692-697, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28823514

RESUMO

Nano- and microfibers obtained by electrospinning have attracted great attention due to its versatility and potential for applications in diverse technological fields. Polyhydroxyalkanoates (PHAs) are biopolymers synthesized by microorganisms such as the bacterium Burkholderia xenovorans LB400. In particular, LB400 cells are capable to synthesize poly(3-hydroxybutyrate) (PHB) from glucose. The aim of this study was to produce and characterize electrospun fibers obtained from bacterial PHBs. Bacterial strain LB400 was grown in M9 minimal medium using xylose and mannitol (10gL-1) as the sole carbon sources and NH4Cl (1gL-1) as the sole nitrogen source. Biopolymer-based films obtained were used to produce fibers by electrospinning. Diameter and morphology of the microfibers were analyzed by scanning electron microscopy (SEM) and their thermogravimetric properties were investigated. Bead-free fibers using both PHBs were obtained with diameters of less than 3µm. The surface morphology of the microfibers based on PHBs obtained from both carbon sources was different, even though their thermogravimetric properties are similar. The results indicate that the carbon source may determine the fiber structure and properties. Further studies should be performed to analyze the physicochemical and mechanical properties of these PHB-based microfibers, which may open up novel applications.


Assuntos
Burkholderia/metabolismo , Glucose/metabolismo , Hidroxibutiratos/metabolismo , Fibras Minerais/análise , Poliésteres/metabolismo , Cloreto de Amônio/metabolismo , Cloreto de Amônio/farmacologia , Burkholderia/efeitos dos fármacos , Meios de Cultura/química , Meios de Cultura/farmacologia , Técnicas Eletroquímicas , Fermentação , Manitol/metabolismo , Manitol/farmacologia , Xilose/metabolismo , Xilose/farmacologia
15.
Part Fibre Toxicol ; 14(1): 29, 2017 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-28784145

RESUMO

BACKGROUND: Man-made vitreous fibres (MMVF) are produced on a large scale for thermal insulation purposes. After extensive studies of fibre effects in the 1980ies and 1990ies, the composition of MMVF was modified to reduce the fibrotic and cancerogenic potential via reduced biopersistence. However, occupational risks by handling, applying, disposing modern MMVF may be underestimated as the conventional regulatory classification -combining composition, in-vivo clearance and effects- seems to be based entirely on MMVF after removal of the binder. RESULTS: Here we report the oxide composition of 23 modern MMVF from Germany, Finland, UK, Denmark, Russia, China (five different producers) and one pre-1995 MMVF. We find that most of the investigated modern MMVF can be classified as "High-alumina, low-silica wool", but several were on or beyond the borderline to "pre-1995 Rock (Stone) wool". We then used well-established flow-through dissolution testing at pH 4.5 and pH 7.4, with and without binder, at various flow rates, to screen the biosolubility of 14 MMVF over 32 days. At the flow rate and acidic pH of reports that found 47 ng/cm2/h dissolution rate for reference biopersistent MMVF21 (without binder), we find rates from 17 to 90 ng/cm2/h for modern MMVF as customary in trade (with binder). Removing the binder accelerates the dissolution significantly, but not to the level of reference biosoluble MMVF34. We finally simulated handling or disposing of MMVF and measured size fractions in the aerosol. The respirable fraction of modern MMVF is low, but not less than pre-1995 MMVF. CONCLUSIONS: The average composition of modern stone wool MMVF is different from historic biopersistent MMVF, but to a lesser extent than expected. The dissolution rates measured by abiotic methods indicate that the binder has a significant influence on dissolution via gel formation. Considering the content of respirable fibres, these findings imply that the risk assessment of modern stone wool may need to be revisited based on in-vivo studies of MMFV as marketed (with binder).


Assuntos
Poluentes Atmosféricos/química , Silicatos de Alumínio/química , Exposição por Inalação/análise , Fibras Minerais/análise , Óxidos/química , Poluentes Atmosféricos/análise , Silicatos de Alumínio/análise , Poeira , Humanos , Concentração de Íons de Hidrogênio , Óxidos/análise , Tamanho da Partícula , Solubilidade , Propriedades de Superfície
16.
Int J Hyg Environ Health ; 220(8): 1230-1241, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28778427

RESUMO

BACKGROUND: The use of off-road vehicles (ORVs) is a popular source of outdoor recreation in the United States. While personal injury has been the focus of most epidemiologic investigations regarding ORV use to date, other health effects associated with ORV use have not been adequately examined. ORVs have been designed to operate in rugged, unpaved terrain, and ORVs can produce copious amounts of fugitive dust. ORV use in geographic regions with naturally occurring asbestos (NOA) and erionite (NOE) may result in the liberation of these minerals from underlying rocks and soil, which may put ORV participants at risk to potentially hazardous inhalation exposures. METHODS: A comprehensive narrative review of existing literature and reports relevant to off-road recreation and mineral fiber exposure was conducted. Manuscripts and reports included in the review were limited to those that contained quantitative data regarding concentrations of mineral fibers recorded during vehicular traffic on an unpaved road and publication in a peer-reviewed journal, official report composed by a government agency, or a report generated under the endorsement of a government agency. In addition, the potential public health impact of ORV use in regions with NOA/NOE was estimated by calculating the proximity of known mineral fiber occurrences to areas of ORV use. RESULTS: A total of 15 publications met inclusion criteria. Exposures to NOA/NOE observed from personal sampling in the included studies ranged from less than 0.01-5.6 f/cc. ORV position while riding in a group and vehicle speed were frequent determinants of measured concentrations. Multiple studies also suggest that children may experience higher exposures to mineral fibers in comparison to adult ORV riders. Information on ORV trails and 665 known occurrences of NOA/NOE was available for five states located in the western United States. Of these 665 known occurrences, approximately 80% (n=515) were located within 20 miles of an ORV trail, and nearly a third were located within one mile. CONCLUSIONS: Individuals who operate ORVs in regions where NOA/NOE is a component of the underlying soil or unpaved road may experience elevated exposures to mineral fibers. Given the prevalence of ORV trails in close proximity to these natural fiber occurrences, epidemiologic and surveillance studies of individuals who frequently engage in ORV use are recommended. Public health initiatives should concentrate on increasing awareness of these risks, allowing ORV users to make informed choices and take appropriate measures to limit these risks where possible.


Assuntos
Poluentes Atmosféricos/análise , Exposição por Inalação/análise , Fibras Minerais/análise , Veículos Off-Road , Monitoramento Ambiental , Humanos
17.
Arch Bronconeumol ; 53(8): 437-442, 2017 Aug.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-28279517

RESUMO

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.


Assuntos
Asbestose/diagnóstico , Asbestose/terapia , Asbestos/classificação , Asbestos/toxicidade , Asbestose/diagnóstico por imagem , Asbestose/prevenção & controle , Biomarcadores Tumorais , Carcinoma Broncogênico/diagnóstico , Carcinoma Broncogênico/etiologia , Carcinoma Broncogênico/terapia , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/etiologia , Neoplasias Pulmonares/terapia , Programas de Rastreamento , Mesotelioma/diagnóstico , Mesotelioma/etiologia , Mesotelioma/terapia , Fibras Minerais/análise , Fibras Minerais/toxicidade , Exposição Ocupacional , Saúde do Trabalhador/legislação & jurisprudência , Doenças Pleurais/diagnóstico , Doenças Pleurais/diagnóstico por imagem , Doenças Pleurais/terapia , Neoplasias Pleurais/diagnóstico , Neoplasias Pleurais/etiologia , Neoplasias Pleurais/terapia , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons , Testes de Função Respiratória , Fumar/epidemiologia , Espanha
18.
Risk Anal ; 37(5): 918-929, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-27393372

RESUMO

This study's objective is to assess the risk of asbestos-related disease being contracted by past users of cosmetic talcum powder.  To our knowledge, no risk assessment studies using exposure data from historical exposures or chamber simulations have been published. We conducted activity-based sampling with cosmetic talcum powder samples from five opened and previously used containers that are believed to have been first manufactured and sold in the 1960s and 1970s.  These samples had been subject to conflicting claims of asbestos content; samples with the highest claimed asbestos content were tested.  The tests were conducted in simulated-bathroom controlled chambers with volunteers who were talc users.  Air sampling filters were prepared by direct preparation techniques and analyzed by phase contrast microscopy (PCM), transmission electron microscopy (TEM) with energy-dispersive x-ray (EDX) spectra, and selective area diffraction (SAED).  TEM analysis for asbestos resulted in no confirmed asbestos fibers and only a single fiber classified as "ambiguous."  Hypothetical treatment of this fiber as if it were asbestos yields a risk of 9.6 × 10-7 (under one in one million) for a lifetime user of this cosmetic talcum powder.  The exposure levels associated with these results range from zero to levels far below those identified in the epidemiology literature as posing a risk for asbestos-related disease, and substantially below published historical environmental background levels.  The approaches used for this study have potential application to exposure evaluations of other talc or asbestos-containing materials and consumer products.


Assuntos
Cosméticos/toxicidade , Pós/toxicidade , Medição de Risco/métodos , Talco/toxicidade , Ar , Asbestos/análise , Cosméticos/análise , Humanos , Exposição por Inalação/análise , Microscopia Eletrônica de Transmissão , Microscopia de Contraste de Fase , Fibras Minerais/análise , Fibras Minerais/toxicidade , Exposição Ocupacional , Pós/análise , Probabilidade , Respiração , Talco/análise , Termogravimetria , Raios X
19.
Arch Bronconeumol ; 53(6): 318-323, 2017 Jun.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-27914752

RESUMO

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.


Assuntos
Asbestos/análise , Líquido da Lavagem Broncoalveolar/química , Pneumopatias/etiologia , Fibras Minerais/análise , Idoso , Asbestos/efeitos adversos , Asbestose/diagnóstico , Asbestose/etiologia , Asbestose/patologia , Broncoscopia , Carcinoma/química , Carcinoma/diagnóstico , Carcinoma/etiologia , Carcinoma/patologia , Feminino , Humanos , Pneumopatias/diagnóstico , Pneumopatias/patologia , Neoplasias Pulmonares/química , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/etiologia , Neoplasias Pulmonares/patologia , Masculino , Mesotelioma/química , Mesotelioma/diagnóstico , Mesotelioma/etiologia , Mesotelioma/patologia , Pessoa de Meia-Idade , Ocupações , Neoplasias Pleurais/química , Neoplasias Pleurais/diagnóstico , Neoplasias Pleurais/etiologia , Neoplasias Pleurais/patologia , Valor Preditivo dos Testes , Curva ROC , Estudos Retrospectivos , Sensibilidade e Especificidade
20.
Chemosphere ; 164: 547-557, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27619065

RESUMO

Relevant mineral fibres of social and economic importance (chrysotile UICC, crocidolite UICC and a fibrous erionite from Jersey, Nevada, USA) were put in contact with cultured diploid human non-tumorigenic bronchial epithelial (Beas2B) and pleural transformed mesothelial (MeT5A) cells to test their cytotoxicity. Slides of each sample at different contact times up to 96 h were studied in situ using synchrotron XRF, µ-XRD and µ-XAS (I18 beamline, Diamond Light Source, UK) and TEM investigations. XRF maps of samples treated for 96 h evidenced that iron is still present within the chrysotile and crocidolite fibres and retained at the surface of the erionite fibres, indicating its null to minor mobilization in contact with cell media; this picture was confirmed by the results of XANES pre-edge analyses. µ-XRD and TEM data indicate greater morphological and crystallinity modifications occurring in chrysotile, whereas crocidolite and erionite show to be resistant in the biological environment. The contact of chrysotile with the cell cultures seems to lead to earlier amorphization, interpreted as the first dissolution step of these fibres. The formation of such silica-rich fibre skeleton may prompt the production of HO in synergy with surface iron species and could indicate that chrysotile may be much more reactive and cytotoxic in vitro in the (very) short term whereas the activity of crocidolite and erionite would be much more sluggish but persistent in the long term.


Assuntos
Asbesto Crocidolita/química , Asbestos Serpentinas/química , Ferro/análise , Fibras Minerais/análise , Zeolitas/química , Animais , Asbesto Crocidolita/toxicidade , Asbestos Serpentinas/toxicidade , Brônquios/efeitos dos fármacos , Carcinogênese/induzido quimicamente , Linhagem Celular , Humanos , Ferro/toxicidade , Fibras Minerais/toxicidade , Mucosa Respiratória/efeitos dos fármacos , Zeolitas/toxicidade
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