RESUMEN
Magnetic exfoliated vermiculite is a synthetic nanocomposite that quickly and efficiently absorbs organic compounds such as oil from water bodies. It was developed primarily to mitigate pollution, but the possible adverse impacts of its application have not yet been evaluated. In this context, the acute toxicity of magnetic exfoliated vermiculite and exfoliated vermiculite was herein assessed by genotoxic and histopathological biomarkers in zebrafish (Danio rerio). DNA fragmentation was statistically significant for all groups exposed to the magnetic exfoliated vermiculite and for fish exposed to the highest concentration (200mg/L) of exfoliated vermiculite, whereas the micronucleus frequency, nuclear abnormalities and histopathological alterations were not statistically significant for the fish exposed to these materials. In the intestinal lumen, epithelial cells and goblet cells, we found the presence of magnetic exfoliated vermiculite and exfoliated vermiculite, but no alterations or presence of the materials-test in the gills or liver were observed. Our findings suggest that the use of magnetic exfoliated vermiculite and exfoliated vermiculite during standard ecotoxicological assays caused DNA damage in D. rerio, whose alterations may be likely to be repaired, indicating that the magnetic nanoparticles have the ability to promote genotoxic damage, such as DNA fragmentation, but not mutagenic effects.
Asunto(s)
Silicatos de Aluminio/toxicidad , Mutágenos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Pez Cebra/fisiología , Animales , Biomarcadores/metabolismoRESUMEN
18F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is widely used to diagnose and stage non-small cell lung cancer (NSCLC). The aim of this retrospective study was to evaluate the predictive ability of different FDG standardized uptake values (SUVs) in 74 patients with newly diagnosed NSCLC. 18F-FDG PET/CT scans were performed and different SUV parameters (SUVmax, SUVavg, SUVT/L, and SUVT/A) obtained, and their relationship with clinical characteristics were investigated. Meanwhile, correlation and multiple stepwise regression analyses were performed to determine the primary predictor of SUVs for NSCLC. Age, gender, and tumor size significantly affected SUV parameters. The mean SUVs of squamous cell carcinoma were higher than those of adenocarcinoma. Poorly differentiated tumors exhibited higher SUVs than well-differentiated ones. Further analyses based on the pathologic type revealed that the SUVmax, SUVavg, and SUVT/L of poorly differentiated adenocarcinoma tumors were higher than those of moderately or well-differentiated tumors. Among these four SUV parameters, SUVT/L was the primary predictor for tumor differentiation. However, in adenocarcinoma, SUVmax was the determining factor for tumor differentiation. Our results showed that these four SUV parameters had predictive significance related to NSCLC tumor differentiation; SUVT/L appeared to be most useful overall, but SUVmax was the best index for adenocarcinoma tumor differentiation.
Asunto(s)
Humanos , Masculino , Persona de Mediana Edad , Silicatos de Aluminio/toxicidad , Enfermedades Profesionales/inducido químicamente , Exposición Profesional/efectos adversos , Fibrosis Pulmonar/inducido químicamente , Biopsia , Resultado Fatal , Pruebas de Función RespiratoriaRESUMEN
This article presents details of fabrication, biological activity (i.e., anti-matrix metalloproteinase [anti-MMP] inhibition), cytocompatibility, and bonding characteristics to dentin of a unique doxycycline (DOX)-encapsulated halloysite nanotube (HNT)-modified adhesive. We tested the hypothesis that the release of DOX from the DOX-encapsulated nanotube-modified adhesive can effectively inhibit MMP activity. We incorporated nanotubes, encapsulated or not with DOX, into the adhesive resin of a commercially available bonding system (Scotchbond Multi-Purpose [SBMP]). The following groups were tested: unmodified SBMP (control), SBMP with nanotubes (HNT), and DOX-encapsulated nanotube-modified adhesive (HNT+DOX). Changes in degree of conversion (DC) and microtensile bond strength were evaluated. Cytotoxicity was examined on human dental pulp stem cells (hDPSCs). To prove the successful encapsulation of DOX within the adhesives-but, more important, to support the hypothesis that the HNT+DOX adhesive would release DOX at subantimicrobial levels-we tested the antimicrobial activity of synthesized adhesives and the DOX-containing eluates against Streptococcus mutans through agar diffusion assays. Anti-MMP properties were assessed via ß-casein cleavage assays. Increasing curing times (10, 20, 40 sec) led to increased DC values. There were no statistically significant differences (p > .05) in DC within each increasing curing time between the modified adhesives compared to SBMP. No statistically significant differences in microtensile bond strength were noted. None of the adhesives eluates were cytotoxic to the human dental pulp stem cells. A significant growth inhibition of S. mutans by direct contact illustrates successful encapsulation of DOX into the experimental adhesive. More important, DOX-containing eluates promoted inhibition of MMP-1 activity when compared to the control. Collectively, our findings provide a solid background for further testing of encapsulated MMP inhibitors into the synthesis of therapeutic adhesives that may enhance the longevity of hybrid layers and the overall clinical performance of adhesively bonded resin composite restorations.
Asunto(s)
Antibacterianos/química , Recubrimientos Dentinarios/química , Doxiciclina/química , Nanotubos/química , Silicatos de Aluminio/síntesis química , Silicatos de Aluminio/química , Silicatos de Aluminio/toxicidad , Antibacterianos/síntesis química , Antibacterianos/toxicidad , Caseínas/efectos de los fármacos , Técnicas de Cultivo de Célula , Arcilla , Recubrimiento Dental Adhesivo , Pulpa Dental/citología , Pulpa Dental/efectos de los fármacos , Dentina/efectos de los fármacos , Dentina/ultraestructura , Recubrimientos Dentinarios/síntesis química , Recubrimientos Dentinarios/toxicidad , Doxiciclina/síntesis química , Doxiciclina/toxicidad , Humanos , Ensayo de Materiales , Metaloproteinasa 1 de la Matriz/efectos de los fármacos , Inhibidores de la Metaloproteinasa de la Matriz/química , Nanotubos/toxicidad , Polimerizacion , Cementos de Resina/síntesis química , Cementos de Resina/química , Cementos de Resina/toxicidad , Células Madre/efectos de los fármacos , Streptococcus mutans/efectos de los fármacos , Estrés Mecánico , Resistencia a la Tracción , Factores de TiempoRESUMEN
The clays consumed by geophagous individuals contain large quantities of aluminum, a known neurological and hematological toxin. This is the first study to evaluate the risk of aluminum poisoning in geophagous individuals. Blind determinations of plasma and urinary aluminum concentrations were carried out in 98 anemic geophagous pregnant women and 85 non-anemic non-geophagous pregnant women. Aluminum concentrations were significantly higher (P < 0.0001) in the geophagous anemic women than in the controls, with odds ratios of 6.83 (95% confidence interval [CI] = 2.72-19.31) for plasma concentrations (13.92 ± 14.09 µg/L versus 4.95 ± 7.11 µg/L) and 5.44 (95% CI = 2.17-14.8) for urinary concentrations (92.83 ± 251.21 µg/L versus 12.11 ± 23 µg/L). The ingested clay is the most likely source of this overexposure to aluminum. If confirmed, the clinical consequences of this absorption for pregnant women and their offspring should be explored.
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Silicatos de Aluminio/toxicidad , Aluminio/envenenamiento , Anemia/etiología , Pica/complicaciones , Complicaciones del Embarazo , Adulto , Aluminio/sangre , Aluminio/orina , Silicatos de Aluminio/química , Anemia/sangre , Anemia/orina , Estudios de Casos y Controles , Arcilla , Femenino , Guyana Francesa , Humanos , Pica/sangre , Pica/orina , Embarazo , Complicaciones del Embarazo/sangre , Complicaciones del Embarazo/etiología , Complicaciones del Embarazo/orina , Adulto JovenRESUMEN
BACKGROUND: Between 1997 and 1999 three sericite plant workers in Parana, Brazil, were diagnosed with pneumoconiosis. AIMS: To investigate and describe the radiological, clinical, and pathological changes in miners and millers exposed to sericite dust with mineralogical characteristics of inhaled dust. METHODS: The working premises were visited to examine the sericite processing and to classify the jobs according to make qualitative evaluation. Respirable dust was collected and the amount of crystalline silica and particle size distribution were measured. Forty four workers were examined by a standard questionnaire for respiratory symptoms, spirometry, and chest x ray. Material from an open lung biopsy was reviewed for histopathological and mineralogical analysis, together with sericite samples from the work site to compare the mineral characteristics in lung lesions and work area. RESULTS: Respirable dust contained 4.5-10.0% crystalline silica. Particle size distribution showed a heavy burden of very fine particles (23-55%) with a mean diameter of <0.5 microm. Mean age of sericite miners was 41.0 (11.9) and mean number of years of exposure was 13.5 (10.1). In 52.3% of workers (23/44), chest radiographs presented a median category of 1/0 or above, and 18.2% (8/44) had a reduced FEV1. There was a significant association between exposure indices and x ray category. Histological studies of the lung biopsy showed lesions compatible with mixed dust fibrosis with no silicotic nodules. x Ray diffraction analysis of the lung dust residue and the bulk samples collected from work area showed similar mineralogical characteristics. Muscovite and kaolinite were the major mineral particle inclusions in the lung. CONCLUSION: Exposure to fine sericite particles is associated with the development of functional and radiological changes in workers inducing mixed dust lesions, which are distinct histologically from silicosis.
Asunto(s)
Silicatos de Aluminio/toxicidad , Minería , Neumoconiosis/etiología , Adulto , Silicatos de Aluminio/análisis , Polvo/análisis , Monitoreo del Ambiente/métodos , Volumen Espiratorio Forzado , Humanos , Exposición por Inhalación/análisis , Masculino , Persona de Mediana Edad , Exposición Profesional/análisis , Tamaño de la Partícula , Neumoconiosis/diagnóstico por imagen , Neumoconiosis/fisiopatología , Fibrosis Pulmonar/etiología , Fibrosis Pulmonar/patología , Radiografía , Dióxido de Silicio/análisis , Capacidad VitalRESUMEN
OBJECTIVES: A substantial amount of Montserrat volcanic ash, containing up to 24% of cristobalite (w/w), a fibrogenic crystalline silica, has been generated since the first documented eruption in 1995. The bioreactivity of the ash and its two major components: cristobalite and anorthite have been studied in vivo for a year following intratracheal instillation into rats. METHODS: The rats (n=5) were instilled with a sterile vehicle solution (0.15 M NaCl) and/or three doses (1.0, 2.5 or 5.0 mg) of each of the dust, and were sacrificed at 13, 25 or 49 weeks post-instillation for quantitative biochemical and histopathological analyses in the lung and lymph nodes. RESULTS: Cristobalite caused inflammation in the lung and granuloma in the hilar lymph nodes associated with significant size augmentation at 13 weeks post-instillation (P<0.05) and cristobalite (5.0 mg) induced fibrosis in the lung at 49 weeks post-exposure. However, the Montserrat volcanic ash caused inflammation in the lung at 49 weeks post-treatment without any fibrogenic response although the ash (5.0 mg) triggered significant lymph node enlargement without significant changes in the lung at 13 weeks post-treatment (P<0.05). Dose and time independent responses in the anorthite-exposed lung and lymph nodes suggest that a single instillation of 5.0 mg of poorly soluble mineral dust does not induce any change in the lung or lymph nodes. CONCLUSION: The ash produces inflammatory reactions in lymph nodes at 13 weeks post-instillation in rats. These effects are seen much earlier than any inflammatory reaction in the lung. The onset of the lung inflammation is delayed until 49 weeks post-exposure. Despite the high cristobalite content of the ash, there is no evidence of any lung fibrogenic responses.
Asunto(s)
Granuloma/inducido químicamente , Pulmón/efectos de los fármacos , Ganglios Linfáticos/efectos de los fármacos , Neumonía/inducido químicamente , Erupciones Volcánicas/efectos adversos , Silicatos de Aluminio/administración & dosificación , Silicatos de Aluminio/toxicidad , Animales , Líquido del Lavado Bronquioalveolar/química , Líquido del Lavado Bronquioalveolar/citología , Relación Dosis-Respuesta a Droga , Fibrosis/inducido químicamente , Fibrosis/patología , Granuloma/patología , Intubación Intratraqueal , Pulmón/metabolismo , Pulmón/patología , Ganglios Linfáticos/patología , Masculino , Tamaño de los Órganos/efectos de los fármacos , Neumonía/metabolismo , Neumonía/patología , Ratas , Ratas Sprague-Dawley , Dióxido de Silicio/administración & dosificación , Dióxido de Silicio/toxicidad , Organismos Libres de Patógenos Específicos , Indias OccidentalesRESUMEN
BACKGROUND: The Soufriere Hills, a stratovolcano on Montserrat, started erupting in July 1995, producing volcanic ash, both from dome collapse pyroclastic flows and phreatic explosions. The eruptions/ash resuspension result in high concentrations of suspended particulate matter in the atmosphere, which includes cristobalite, a mineral implicated in respiratory disorders. AIMS: To conduct toxicological studies on characterised samples of ash, together with major components of the dust mixture (anorthite, cristobalite), and a bioreactive mineral control (DQ12 quartz). METHODS: Rats were challenged with a single mass (1 mg) dose of particles via intratracheal instillation and groups sacrificed at one, three, and nine weeks. Acute bioreactivity of the particles was assessed by increases in lung permeability and inflammation, changes in epithelial cell markers, and increase in the size of bronchothoracic lymph nodes. RESULTS: Data indicated that respirable ash derived from pyroclastic flows (20.1% cristobalite) or phreatic explosion (8.6% cristobalite) had minimal bioreactivity in the lung. Anorthite showed low bioreactivity, in contrast to pure cristobalite, which showed progressive increases in lung damage. CONCLUSION: Results suggests that either the percentage mass of cristobalite particles present in Montserrat ash was not sufficient as a catalyst in the lung environment, or its surface reactivity was masked by the non-reactive volcanic glass components during the process of ash formation.
Asunto(s)
Silicatos de Aluminio/toxicidad , Polvo/efectos adversos , Pulmón , Dióxido de Silicio/toxicidad , Erupciones Volcánicas/efectos adversos , Animales , Líquido del Lavado Bronquioalveolar/citología , Células Epiteliales/efectos de los fármacos , Pulmón/patología , Masculino , Minerales/análisis , Tamaño de los Órganos/efectos de los fármacos , Surfactantes Pulmonares/metabolismo , Ratas , Ratas Sprague-Dawley , Indias OccidentalesRESUMEN
Se efectuó un estudio de toxicidad aguda al producto dermasel en el cual se emplearon un total de 50 ratones de la linea Balbc divididos en cinco grupos, a los cuales de les administró cuatro niveles de dosis que se correspondan con: 700, 1050, 1575 y 2365 mg de peso corporal. La administración del producto se efectuó por vía oral, con la ayuda de una cánula de 3cm. Durante el desarrollo del experimento se observaron detenidamente los animales, y se anotaron los síntomas y signos de toxicidad. Al finalizar el estudio, se procesaron los datos por el método estadístico de Litdhield y Wilcoxon, los que permitió calcular el valor de la LD50 y clasificar el producto como ligeramente toxico