Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 87.155
Filtrar
1.
Int J Prosthodont ; 34(1): 54-60, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570520

RESUMEN

PURPOSE: To evaluate the physical and mechanical properties of maxillofacial silicone elastomers following the incorporation of a specific particle size and concentration of nano-titanium dioxide (TiO2) and nano-zinc oxide (ZnO). MATERIALS AND METHODS: Nano-TiO2 and nano-ZnO of 20-nm and 40-nm particle sizes and in 1% and 2% concentrations were chosen. Silicone elastomer samples were prepared according to the manufacturer's recommendations. The nano-oxides were incorporated via hand spatulation. The samples were subsequently tested for hardness and color stability and were then subjected to aging in an aging chamber for 1,008 hours, following which they were again evaluated for hardness, color stability, and surface roughness. RESULTS: A significant change was noted in the physical and mechanical properties post-aging in all the groups. The samples with nano-TiO2 of 40-nm particle size/2% concentration had the highest hardness, while color stability and surface roughness were higher in samples with nano-TiO2 of 20-nm particle size/1% and 2% concentrations, respectively. CONCLUSION: It can be concluded that 20-nm nano-TiO2 particles best maintain the ideal properties of maxillofacial silicone elastomers and can potentially be used as alternative opacifiers when mixed with A-2186 maxillofacial silicone elastomers.


Asunto(s)
Prótesis Maxilofacial , Elastómeros de Silicona , Color , Ensayo de Materiales , Óxidos , Tamaño de la Partícula
2.
Proc Natl Acad Sci U S A ; 118(8)2021 02 23.
Artículo en Inglés | MEDLINE | ID: mdl-33563754

RESUMEN

COVID-19 transmits by droplets generated from surfaces of airway mucus during processes of respiration within hosts infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. We studied respiratory droplet generation and exhalation in human and nonhuman primate subjects with and without COVID-19 infection to explore whether SARS-CoV-2 infection, and other changes in physiological state, translate into observable evolution of numbers and sizes of exhaled respiratory droplets in healthy and diseased subjects. In our observational cohort study of the exhaled breath particles of 194 healthy human subjects, and in our experimental infection study of eight nonhuman primates infected, by aerosol, with SARS-CoV-2, we found that exhaled aerosol particles vary between subjects by three orders of magnitude, with exhaled respiratory droplet number increasing with degree of COVID-19 infection and elevated BMI-years. We observed that 18% of human subjects (35) accounted for 80% of the exhaled bioaerosol of the group (194), reflecting a superspreader distribution of bioaerosol analogous to a classical 20:80 superspreader of infection distribution. These findings suggest that quantitative assessment and control of exhaled aerosol may be critical to slowing the airborne spread of COVID-19 in the absence of an effective and widely disseminated vaccine.


Asunto(s)
/fisiopatología , Espiración/fisiología , Obesidad/fisiopatología , Aerosoles , Factores de Edad , Animales , Índice de Masa Corporal , /virología , Estudios de Cohortes , Humanos , Moco/química , Moco/virología , Obesidad/epidemiología , Obesidad/virología , Tamaño de la Partícula , Primates , Sistema Respiratorio/metabolismo , Carga Viral
3.
Nat Commun ; 12(1): 899, 2021 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-33563998

RESUMEN

Analytical limitations considerably hinder our understanding of the impacts of the physicochemical properties of nanomaterials (NMs) on their biological fate in organisms. Here, using a fit-for-purpose analytical workflow, including dosing and emerging analytical techniques, NMs present in organisms are characterized and quantified across an aquatic food chain. The size and shape of gold (Au)-NMs are shown to control the number of Au-NMs attached to algae that were exposed to an equal initial concentration of 2.9 × 1011 particles mL-1. The Au-NMs undergo size/shape-dependent dissolution and agglomeration in the gut of the daphnids, which determines the size distribution of the NMs accumulated in fish. The biodistribution of NMs in fish tissues (intestine, liver, gills, and brain) also depends on NM size and shape, although the highest particle numbers per unit of mass are almost always present in the fish brain. The findings emphasize the importance of physicochemical properties of metallic NMs in their biotransformations and tropic transfers.


Asunto(s)
Cadena Alimentaria , Oro/metabolismo , Nanoestructuras , Contaminantes Químicos del Agua/metabolismo , Animales , Bioacumulación , Biotransformación , Daphnia/metabolismo , Peces/metabolismo , Oro/química , Microalgas/metabolismo , Nanoestructuras/química , Tamaño de la Partícula , Especificidad de la Especie , Distribución Tisular , Contaminantes Químicos del Agua/química
4.
Int J Nanomedicine ; 16: 515-538, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33519199

RESUMEN

Background: Several studies have demonstrated various molecular mechanisms involved in the biogenesis and release of exosomes. However, how external stimuli, such as platinum nanoparticles (PtNPs), induces the biogenesis and release of exosomes remains unclear. To address this, PtNPs were synthesized using lutein to examine their effect on the biogenesis and release of exosomes in human lung epithelial adenocarcinoma cancer cells (A549). Methods: The size and concentration of isolated exosomes were characterized by dynamic light scattering (DLS) and nanoparticle tracking analysis system (NTA). Morphology and structure of exosomes were examined using scanning electron microscopy and transmission electron microscopy (TEM), respectively. Quantification of exosomes were analyzed by EXOCETTM assay and fluorescence polarization (FP). The expression of typical markers of exosomes were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). Results: A549 cells cultured with PtNPs enhance exosome secretion by altering various physiological processes. Interestingly, A549 cells treated with PtNPs increases total protein concentration, biogenesis and release of exosomes associated with PtNPs-induced oxidative stress. GW4869 inhibits PtNPs induced biogenesis and release of exosomes and also acetylcholinesterase (AChE), neutral sphingomyelinase activity (n-SMase), and exosome counts. A549 cells pre-treated with N-acetylcysteine (NAC) significantly inhibited PtNPs induced exosome biogenesis and release. These findings confirmed that PtNPs-induced exosome release was due to the induction of oxidative stress and the ceramide pathway. These factors enhanced exosome biogenesis and release and may be useful in understanding the mechanism of exosome formation, release, and function. Conclusion: PtNPs provide a promising agent to increase exosome production in A549 cells. These findings offer novel strategies for enhancing exosome release, which can be applied in the treatment and prevention of cancer. Importantly, this is the first study, to our knowledge, showing that PtNPs stimulate exosome biogenesis by inducing oxidative stress and the ceramide pathway.


Asunto(s)
Adenocarcinoma del Pulmón/metabolismo , Ceramidas/metabolismo , Exosomas/metabolismo , Neoplasias Pulmonares/metabolismo , Nanopartículas del Metal/química , Estrés Oxidativo , Platino (Metal)/farmacología , Células A549 , Acetilcolinesterasa/metabolismo , Acetilcisteína/farmacología , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/patología , Compuestos de Anilina/farmacología , Compuestos de Bencilideno/farmacología , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Exosomas/ultraestructura , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Luteína/farmacología , Nanopartículas del Metal/ultraestructura , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Estrés Oxidativo/efectos de los fármacos , Tamaño de la Partícula , ARN Mensajero/genética , ARN Mensajero/metabolismo , Suero , Esfingomielina Fosfodiesterasa/metabolismo , Electricidad Estática
5.
Int J Nanomedicine ; 16: 579-589, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33531802

RESUMEN

Purpose: Breast cancer is one of the most lethal types of cancer in women. Curcumin showed therapeutic potential against breast cancer, but applying that by itself does not lead to the associated health benefits due to its poor bioavailability, which appears to be primarily due to poor absorption, rapid metabolism, and rapid elimination. Moreover, poor water solubility of curcumin causes accumulation of a high concentration of curcumin and so decrease its permeability to the cell. Many strategies are employed to reduce curcumin metabolism such as adjuvants and designing novel delivery systems. Therefore, in this study sodium alginate and chitosan were used to synthesize the hydrogels that are known as biocompatible, hydrophilic and low toxic drug delivery systems. Also, folic acid was used to link to chitosan in order to actively targetfolate receptors on the cells. Methods: Chitosan-ß-cyclodextrin-TPP-Folic acid/alginate nanoparticles were synthesized and then curcumin was loaded on them. Interaction between the constituents of the particles was characterized by FTIR spectroscopy. Morphological structures of samples were studied by FE-SEM. Release profile of curcumin was determined by dialysis membrane. The cytotoxic test was done on the Kerman male breast cancer (KMBC-10) cell line by using MTT assay. The viability of cells was detected by fluorescent staining. Gene expression was investigated by real-time PCR. Results: The encapsulation of curcumin into nano-particles showed an almost spherical shape and an average particle size of 155 nm. In vitro cytotoxicity investigation was indicated as dose-respond reaction against cancer breast cells after 24 h incubation. On the other hand, in vitro cell uptake study revealed active targeting of CUR-NPs into spheroids. Besides, CXCR 4 expression was detected about 30-fold less than curcumin alone. The CUR-NPs inhibited proliferation and increased apoptosis in spheroid human breast cancer cells. Conclusion: Our results showed the potential of NPs as an effective candidate for curcumin delivery to the target tumor spheroids that confirmed the creatable role of folate receptors.


Asunto(s)
Alginatos/química , Quitosano/química , Curcumina/farmacología , Nanosferas/química , Esferoides Celulares/patología , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Neoplasias de la Mama/patología , Línea Celular Tumoral , Femenino , Fluorescencia , Ácido Fólico/uso terapéutico , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Masculino , Nanosferas/ultraestructura , Tamaño de la Partícula , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Esferoides Celulares/efectos de los fármacos
6.
Int J Nanomedicine ; 16: 591-607, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33531803

RESUMEN

Purpose: The aim of the present study was to develop deflazacort (DFZ) ultra-elastic nanovesicles (UENVs) loaded gel for topical administration to evade gastrointestinal adverse impacts accompanying DFZ oral therapy. Methods: UENVs were elaborated according to D-optimal mixture design employing different edge activators as Span-60, Tween-85 and sodium cholate which were incorporated into the nanovesicles to improve the deformability of vesicles bilayer. DFZ-UENVs were formulated by thin-film hydration technique followed by characterization for different parameters including entrapment efficiency (%EE), particle size, in vitro release and ex vivo permeation studies. The composition of the optimized DFZ-UENV formulation was found to be DFZ (10 mg), Span-60 (30 mg), Tween-85 (30 mg), sodium cholate (3.93 mg), L-α phosphatidylcholine (60 mg) and cholesterol (30 mg). The optimum formulation was incorporated into hydrogel base then characterized in terms of physical parameters, in vitro drug release, ex vivo permeation study and pharmacodynamics evaluation. Finally, pharmacokinetic study in rabbits was performed via transdermal application of UENVs gel in comparison to oral drug. Results: The optimum UENVs formulation exhibited %EE of 74.77±1.33, vesicle diameter of 219.64±2.52 nm, 68.88±1.64% of DFZ released after 12 h and zeta potential of -55.57±1.04 mV. The current work divulged successful augmentation of the bioavailability of DFZ optimum formulation by about 1.37-fold and drug release retardation compared to oral drug tablets besides significant depression of edema, cellular inflammation and capillary congestion in carrageenan-induced rat paw edema model. Conclusion: The transdermal DFZ-UENVs can achieve boosted bioavailability and may be suggested as an auspicious non-invasive alternative platform for oral route.


Asunto(s)
Antiinflamatorios/farmacología , Sistemas de Liberación de Medicamentos , Elasticidad , Nanopartículas/química , Pregnenodionas/farmacología , Administración Cutánea , Administración Oral , Animales , Disponibilidad Biológica , Liberación de Fármacos , Edema/tratamiento farmacológico , Hidrogeles/química , Masculino , Nanopartículas/ultraestructura , Tamaño de la Partícula , Pregnenodionas/farmacocinética , Conejos , Ratas Wistar , Absorción Cutánea/efectos de los fármacos , Electricidad Estática , Comprimidos
7.
Int J Nanomedicine ; 16: 609-621, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33531804

RESUMEN

Objective: The aim of the current study was to load fenticonazole nitrate, a slightly water-soluble antifungal agent, into terpene-enriched phospholipid vesicles (terpesomes) as a potential delivery system for the management of ocular fungal infection. Methods: Thin film hydration method was used to prepare terpesomes according to a 32 full factorial design to inspect the effect of several variables on vesicles' features. The investigated factors were terpenes type (X1) and terpenes amount (X2) while the dependent responses were encapsulation efficiency percent (Y1), particle size (Y2) and polydispersity index (Y3). Design Expert® program was used to chose the best achieved formula. The selected terpesomes were further optimized via incorporation of a positive charge inducer (stearylamine) to enhance adhesion to the negatively charged mucus covering the eye surface. The in vivo performance of the optimized fenticonazole nitrate-loaded terpesomes relative to drug suspension was evaluated by measuring the antifungal activity (against Candida albicans) retained in the tear's fluid at different time intervals after ocular application in albino rabbits. Results: The optimized terpesomes showed spherical vesicles with entrapment efficiency of 79.02±2.35%, particle size of 287.25±9.55 nm, polydispersity index of 0.46±0.01 and zeta potential of 36.15±1.06 mV. The in vivo study demonstrated significantly higher ocular retention of the optimized fenticonazole nitrate-loaded terpesomes relative to the drug suspension. Moreover, the histopathological studies proved the safety and biocompatibility of the prepared terpesomes. Conclusion: The obtained results verified the potential of the terpesomes for safe and effective ocular delivery of fenticonazole nitrate.


Asunto(s)
Sistemas de Liberación de Medicamentos , Ojo/efectos de los fármacos , Imidazoles/administración & dosificación , Terpenos/farmacología , Administración Cutánea , Animales , Antifúngicos/farmacología , Candida albicans/efectos de los fármacos , Portadores de Fármacos/química , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Masculino , Pruebas de Sensibilidad Microbiana , Tamaño de la Partícula , Conejos , Suspensiones
8.
Int J Nanomedicine ; 16: 651-665, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33536753

RESUMEN

Objective: This study was intended to utilize lecithin-based mixed polymeric micelles (lbMPMs) for enhancing the solubility and bioavailability of honokiol and magnolol to resolve the hindrance of their extreme hydrophobicity on the clinical applications. Methods: Lecithin was selected to increase the volume of the core of lbMPMs, thereby providing a greater solubilization capacity. A series of amphiphilic polymers (sodium deoxycholate [NaDOC], Cremophor®, and Pluronic® series) were included with lecithin for screening and optimization. Results: After preliminary evaluation and subsequentially optimization, two lbMPMs formulations composed of honokiol/magnolol:lecithin:NaDOC (lbMPMs[NaDOC]) and honokiol/magnolol:lecithin:PP123 (lbMPMs[PP123]) in respective ratios of 6:2:5 and 1:1:10 were optimally obtained with the mean particle sizes of 80-150 nm, encapsulation efficacy (EEs) of >90%, and drug loading (DL) of >9.0%. These lbMPMs efficiently stabilized honokiol/magnolol in phosphate-buffered saline (PBS) at room temperature or 4 °C and in fetal bovine serum or PBS at 37 °C. PK study demonstrated that lbMPMs[NaDOC] showed much improvement in enhancing bioavailability than that by lbMPMs[PP123] for both honokiol and magnolol. The absolute bioavailability for honokiol and magnolol after intravenous administration of lbMPMs[NaDOC] exhibited 0.93- and 3.4-fold increases, respectively, compared to that of free honokiol and magnolol. For oral administration with lbMPMs[NaDOC], the absolute bioavailability of honokiol was 4.8%, and the absolute and relative bioavailability of magnolol were 20.1% and 2.9-fold increase, respectively. Conclusion: Overall, honokiol/magnolol loaded in lbMPMs[NaDOC] showed an improvement of solubility with suitable physical characteristics leading to enhance honokiol and magnolol bioavailability and facilitating their wider application as therapeutic agents for treating human disorders.


Asunto(s)
Compuestos de Bifenilo/farmacología , Lecitinas/química , Lignanos/farmacología , Micelas , Polímeros/química , Administración Oral , Animales , Disponibilidad Biológica , Compuestos de Bifenilo/sangre , Compuestos de Bifenilo/química , Compuestos de Bifenilo/farmacocinética , Liberación de Fármacos , Humanos , Lignanos/sangre , Lignanos/química , Lignanos/farmacocinética , Masculino , Tamaño de la Partícula , Ratas Sprague-Dawley , Solubilidad
9.
Int J Nanomedicine ; 16: 683-700, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33536754

RESUMEN

Purpose: To develop an externally triggered rapid-release targeted system for treating ovarian cancer, gemcitabine (GMC) was entrapped into sonosensitive (SoS) folate (Fo)-modified liposomes (LPs). Methods: GMC-loaded LPs (GMC LPs), GMC-loaded Fo-targeted LPs (GMC-Fo LPs), and GMC-loaded Fo-targeted SoS LPs (GMC-SoS Fo LPs) were prepared utilizing a film-hydration technique and evaluated based on particle size, ζ-potential, and percentage entrapped drug. Cellular uptake of the fluorescent delivery systems in Fo-expressing ovarian cancer cells was quantified using flow cytometry. Finally, tumor-targeting ability, in vivo evaluation, and pharmacokinetic studies were performed. Results: GMC LPs, GMC-Fo LPs, and GMC-SoS Fo LPs were successfully prepared, with sizes of <120.3±2.4 nm, 39.7 mV ζ-potential, and 86.3%±1.84% entrapped drug. Cellular uptake of GMC-SoS Fo LPs improved 6.51-fold over GMC LPs (under ultrasonic irradiation - p<0.05). However, cellular uptake of GMC-Fo LPs improved just 1.24-fold over GMC LPs (p>0.05). Biodistribution study showed that of GMC concentration in tumors treated with GMC-SoS-Fo LPs (with ultrasound) improved 2.89-fold that of free GMC (p<0.05). In vivo, GMC-SoS Fo LPs showed the highest antiproliferative and antitumor action on ovarian cancer. Conclusion: These findings showed that externally triggered rapid-release SoS Fo-modified LPs are a promising system for delivering rapid-release drugs into tumors.


Asunto(s)
Desoxicitidina/análogos & derivados , Ácido Fólico/química , Ultrasonido , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/sangre , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapéutico , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Desoxicitidina/administración & dosificación , Desoxicitidina/sangre , Desoxicitidina/farmacocinética , Desoxicitidina/farmacología , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Endocitosis/efectos de los fármacos , Femenino , Humanos , Liposomas , Neoplasias Ováricas/sangre , Neoplasias Ováricas/tratamiento farmacológico , Neoplasias Ováricas/patología , Tamaño de la Partícula , Ratas Sprague-Dawley , Distribución Tisular/efectos de los fármacos
10.
Int J Nanomedicine ; 16: 715-724, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33542626

RESUMEN

Objective: The coronavirus disease (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is now rapidly spreading globally. Serological tests are an important method to assist in the diagnosis of COVID-19, used for epidemiological investigations. In this study, we aimed to investigate the impact of different types of vacuum collection tubes on the detection of SARS-CoV-2 IgM and IgG antibodies, using the colloidal gold immunochromatographic assay (GICA). Patients and Methods: A total of 112 patients with COVID-19 and 200 healthy control subjects with no infection were enrolled in this study. Their serum and plasma were collected into four different types of vacuum blood collection tubes. SARS-CoV-2 IgM and IgG specific antibodies in the plasma and serum were then detected by GICA and chemiluminescence assay (CA), respectively. In addition, the particle sizes of different colloidal gold solutions in the presence of different anticoagulants and coagulants were evaluated by both laser diffraction (Malvern) and confocal laser microscope, respectively. Results: Our results revealed that anticoagulated plasma with EDTA-K2 improved the positive detection rate of SARS-CoV-2 IgM antibodies. Furthermore, our results shown that the detection results by GICA and CA were highly consistent, especially, the results of EDTA-K2 anticoagulated plasma detected by GICA was more consistent with CA results. We confirmed that EDTA-K2 could improve the detection sensitivity of SARS-CoV-2 IgG antibodies by chelating excessive colloidal gold compared with sodium citrate or lithium heparin, these methodologies did not appear to cause false positives. Colloidal gold particles could be chelated and aggregated by EDTA-K2, but not by sodium citrate, lithium heparin and coagulants. Conclusion: GICA is widely used to detect antibodies for the advantages of convenient, fast, low cost, suitable for screening large sample and require minimal equipment. In this study, we found that EDTA-K2 amplified the positive antibody signal by chelating colloidal gold and improved the detection sensitivity of SARS-CoV-2 IgM and IgG antibodies when using the GICA. Therefore, we suggested that EDTA-K2 anticoagulated plasma was more suitable for the detection of SARS-CoV-2 antibodies.


Asunto(s)
Anticuerpos Antivirales/aislamiento & purificación , Quelantes/química , Ácido Edético/química , Oro Coloide/química , Inmunoensayo/métodos , Inmunoglobulina G/aislamiento & purificación , Inmunoglobulina M/aislamiento & purificación , /inmunología , Adulto , Anticuerpos Antivirales/sangre , Especificidad de Anticuerpos/inmunología , /inmunología , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Peso Molecular , Tamaño de la Partícula , Polímeros/química , Sensibilidad y Especificidad
11.
PLoS One ; 16(2): e0246543, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33539439

RESUMEN

Dental turbines and scalers, used every day in dental operatories, feature built-in water spray that generates considerable amounts of water aerosol. The problem is that it is not exactly known how much. Since the outbreak of COVID-19, several aerosol safety recommendations have been issued-based on little empirical evidence, as almost no data are available on the exact aerosol concentrations generated during dental treatment. Similarly, little is known about the differences in the efficacy of different commercially available aerosol control systems to reduce in-treatment aerosol load. In this in vitro study, we used spectrometry to explore these questions. The time-dependent effect of conventional airing on aerosol concentrations was also studied. Everyday patient treatment situations were modeled. The test setups were defined by the applied instrument and its spray direction (high-speed turbine with direct/indirect airspray or ultrasonic scaler with indirect airspray) and the applied aerosol control system (the conventional high-volume evacuator or a lately introduced aerosol exhaustor). Two parameters were analyzed: total number concentration in the entire measurement range of the spectrometer and total number concentration within the 60 to 384 nm range. The results suggest that instrument type and spray direction significantly influence the resulting aerosol concentrations. Aerosol generation by the ultrasonic scaler is easily controlled. As for the high-speed turbine, the efficiency of control might depend on how exactly the instrument is used during a treatment. The results suggest that scenarios where the airspray is frequently directed toward the air of the operatory are the most difficult to control. The tested control systems did not differ in their efficiency, but the study could not provide conclusive results in this respect. With conventional airing through windows with a standard fan, a safety airing period of at least 15 minutes between treatments is recommended.


Asunto(s)
Aerosoles/efectos adversos , Instrumentos Dentales/virología , Odontología/métodos , Aerosoles/administración & dosificación , Aerosoles/análisis , Diseño de Equipo , Humanos , Tamaño de la Partícula , /aislamiento & purificación
13.
Ecotoxicol Environ Saf ; 208: 111718, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396049

RESUMEN

Plastics enter in terrestrial natural system primarily by agricultural purposes, while acid rain is the result of anthropogenic activities. The synergistic effects of microplastics and acid rain on plant growth are not known. In this study, different sizes of polyethylene terephthalate (PET) and acid rain are tested on Lepidium sativum, in two separate experimental sets. In the first one we treated plants only with PET, in the second one we used PET and acid rain together. In both experimentations we analyzed: i) plant biometrical parameters (shoot height, leaf number, percentage inhibition of seed germination, fresh biomass), and ii) oxidative stress responses (hydrogen peroxide; ascorbic acid and glutathione). Results carried out from our experiments highlighted that different sizes of polyethylene terephthalate are able to affect plant growth and physiological responses, with or without acid rain supplied during acute toxicity (6 days). SHORT DESCRIPTION: This study showed that different sizes of PET microplastics affect physiological and biometrical responses of Lepidum sativum seedlings, with or without acid rain; roots and leaves responded differently.


Asunto(s)
Lluvia Ácida/toxicidad , Lepidium sativum/efectos de los fármacos , Microplásticos/toxicidad , Tereftalatos Polietilenos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Lepidium sativum/crecimiento & desarrollo , Lepidium sativum/metabolismo , Lepidium sativum/fisiología , Microplásticos/química , Estrés Oxidativo/efectos de los fármacos , Tamaño de la Partícula , Hojas de la Planta/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Tereftalatos Polietilenos/química , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Plantones/fisiología , Contaminantes Químicos del Agua/química
14.
Ecotoxicol Environ Saf ; 208: 111720, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396051

RESUMEN

Fine particulate matter (PM2.5), a ubiquitous environmental pollutant, has been indicated to affect thyroid hormone (TH) homeostasis in women, but the detailed mechanism behind this effect remains unclear. The objective of this study was to evaluate the roles of the hypothalamic-pituitary-thyroid (HPT) axis and hepatic transthyretin in the thyroid-disrupting effects of PM2.5. Sprague Dawley rats were treated with PM2.5 (0, 15 and 30 mg/kg) by passive pulmonary inhalation for 49 days; and recovery experimental group rats were dosed with PM2.5 (30 mg/kg) for 35 days, and no treatment was done during the subsequent 14 days. PM2.5 was handled twice a day by passive pulmonary inhalation throughout the study. After treatment, pathological changes were analyzed by performing haemotoxylin and eosin staining, measuring levels of THs and urine iodine (UI) in serum, plasma, and urine samples using enzyme-linked immunoabsorbent assay, and expression of proteins in the hypothalamus, pituitary, thyroid, and liver tissues of rats were analyzed by immunohistochemistry and Western blotting. The levels of oxidative stress factors, such as reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (Gpx), and nuclear factor-kappa B (NF-κB) in female rats' plasma were also evaluated by ELISA. The results of these analyses revealed that PM2.5 treatment induced pathologic changes in rat thyroid and liver characterized by increased follicular cavity size and decreased amounts of follicular epithelial cells and fat vacuoles, respectively. Serum levels of triiodothyronine, thyroxine, and thyroid stimulating hormone were significantly decreased, plasma NF-κB level was increased and plasma redox state was unbalanced (enhanced ROS, MDA and Gpx levels; reduced SOD activities) in female rats treated with PM2.5 (P < 0.05). PM2.5 treatment suppressed the biosynthesis and biotransformation of THs by increasing sodium iodide symporter, thyroid transcription factor 1, thyroid transcription factor 2, and paired box 8 protein expression levels (P < 0.05). Additionally, thyroid stimulating hormone receptor and thyroid peroxidase levels were significantly decreased (P < 0.05). Both thyrotropin releasing hormone receptor and thyroid stimulating hormone beta levels were enhanced (P < 0.05). Moreover, transport of THs was inhibited due to reduced protein expression of hepatic transthyretin upon treatment with PM2.5. In summary, PM2.5 treatment could perturb TH homeostasis by affecting TH biosynthesis, biotransformation, and transport, affecting TH receptor levels, and inducing oxidative stress and inflammatory responses. Activation of the HPT axis and altered hepatic transthyretin levels therefore appear to play a crucial role in PM2.5-induced thyroid dysfunction.


Asunto(s)
Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Material Particulado/toxicidad , Prealbúmina/metabolismo , Glándula Tiroides/efectos de los fármacos , Hormonas Tiroideas/metabolismo , Animales , Femenino , Homeostasis/efectos de los fármacos , Sistema Hipotálamo-Hipofisario/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Estrés Oxidativo/efectos de los fármacos , Tamaño de la Partícula , Material Particulado/química , Ratas , Ratas Sprague-Dawley , Receptores de Hormona Tiroidea/metabolismo , Glándula Tiroides/metabolismo , Glándula Tiroides/patología
15.
Ecotoxicol Environ Saf ; 208: 111702, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396033

RESUMEN

Cellular models exhibiting human physiological features of pseudostratified columnar epithelia, provide a more realistic approach for elucidating detailed mechanisms underlying PM2.5-induced pulmonary toxicity. In this study, we characterized the barrier and mucociliary functions of differentiated human small airway epithelial cells (SAECs), cultured at the air-liquid interface (ALI). Due to the presence of mucociliary protection, particle internalization was reduced, with a concomitant decrease in cytotoxicity in differentiated S-ALI cells, as compared to conventional submerged SAEC cultures. After 24-hour exposure to PM2.5 surrogates, 117 up-regulated genes and 156 down-regulated genes were detected in S-ALI cells, through transcriptomic analysis using the Affymetrix Clariom™ S Human Array. Transcription-level changes in >60 signaling pathways, were revealed by functional annotation of the 273 differentially expressed genes, using the PANTHER Gene List Analysis. These pathways are involved in multiple cellular processes, that include inflammation and apoptosis. Exposure to urban PM2.5 led to complex responses in airway epithelia, including a net induction of downstream pro-inflammatory and pro-apoptotic responses. Collectively, this study highlights the importance of using the more advanced ALI model rather than the undifferentiated submerged model, to avoid over-assessment of inhaled particle toxicity in human. The results of our study also suggest that reduction of ambient PM2.5 concentrations would have a protective effect on respiratory health in humans.


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Células Epiteliales/efectos de los fármacos , Material Particulado/toxicidad , Transcriptoma/efectos de los fármacos , Contaminantes Atmosféricos/química , Apoptosis/efectos de los fármacos , Células Cultivadas , Células Epiteliales/metabolismo , Células Epiteliales/patología , Perfilación de la Expresión Génica , Humanos , Tamaño de la Partícula , Material Particulado/química , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
16.
Ecotoxicol Environ Saf ; 208: 111618, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396138

RESUMEN

Air pollution has been recognized to be a risk factor for lung cancer. The objective of this study was to investigate the effects of air pollution on heavy metal alterations in the pleural effusion of lung cancer patients. Pleural effusion was collected from patients with lung cancer and congestive heart failure (CHF). One-year average levels of particulate matter with an aerodynamic diameter of < 10 µm (PM10), PM2.5, NO2, and SO2 were linked to the exposure of these subjects. Traffic-related metals, included Al, Fe, Cu, Zn, and Pb, were determined in the pleural effusion. Logistic regression models were used to examine their associations. There were 63 lung cancer patients and 31 CHF patients enrolled in the current study. We found that PM10, PM2.5, and NO2 were negatively correlated with Al in the pleural effusion, whereas PM2.5 was positively correlated with Zn in the pleural effusion. Increases in 1 µg/m3 of PM2.5 and 1 ng/mL of Zn were associated with lung cancer (adjusted OR=2.394, 95% CI= 1.446-3.964 for PM2.5; adjusted OR=1.003, 95% CI=1.000-1.005 for Zn). Increases in PM2.5 and Zn in the pleural effusion increased the risk of malignant pleural effusion in lung cancer patients (adjusted OR=1.517; 95% CI=1.082-2.127 for PM2.5; adjusted OR=1.002, 95% CI=1.000-1.005 for Zn). Furthermore, we observed that adenocarcinomas increased in association with a 1-µg/m3 increase in PM2.5 (crude OR=1.683; 95% CI=1.006-2.817) in lung cancer patients. In conclusion, PM2.5 exposure and the possible resultant Zn in the pleural effusion associated with the development of malignant pleural effusion in lung cancer.


Asunto(s)
Contaminantes Atmosféricos/análisis , Exposición a Riesgos Ambientales/análisis , Neoplasias Pulmonares/epidemiología , Metales Pesados/análisis , Material Particulado/análisis , Derrame Pleural Maligno/epidemiología , Anciano , Contaminantes Atmosféricos/toxicidad , Exposición a Riesgos Ambientales/efectos adversos , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Metales Pesados/toxicidad , Persona de Mediana Edad , Tamaño de la Partícula , Material Particulado/toxicidad , Derrame Pleural Maligno/química , Derrame Pleural Maligno/patología , Factores de Riesgo , Taiwán
17.
Environ Monit Assess ; 193(2): 54, 2021 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-33428009

RESUMEN

The heavy metal pollution level in soils is heavily affected by the soil particle size distribution. However, the heavy metal loss during particle size extraction and the effect of calcite on the heavy metals removal in terms of the particle size are unclear. In this study, the distribution of heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb, U, and V) was determined in five particle fractions (> 2, 2-0.25, 0.25-0.02, 0.02-0.002, and < 0.002 mm) of two soil and one sediment samples collected from the floodplain of Dongchuan, Yunnan Province, Southwest China. The sampled floodplain soils were mainly composed of gravel and sand fractions (> 97%). The concentrations of all nine heavy metals in the sampled soils and sediment increase significantly with decreasing particle sizes. The maximal loss rate of Cd and Cu reaches 54% and 8.6%, respectively, which should be considered in the process of particle size fraction extraction in soils. The removal amount and removal rate of heavy metals in solution by pure calcite ranks in the order of Pb2+ > Cu2+ > Cr6+, while the removal rate of Pb (93.13%) is much higher than that of Cu (24.56%) and Cr (10.71%), which increase with the calcite particle size decreasing. The stabilization of carbonate minerals in soils is crucial for heavy metal pollution control in floodplain soils with high carbonate concentrations in Dongchuan, China.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , China , Monitoreo del Ambiente , Metales Pesados/análisis , Tamaño de la Partícula , Suelo , Contaminantes del Suelo/análisis
18.
Ecotoxicol Environ Saf ; 208: 111726, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33396057

RESUMEN

BACKGROUND: It remains unclear which size of particles has the strongest effects on heart rate variability (HRV). OBJECTIVE: To explore the association between HRV parameters and daily variations of size-fractionated particle number concentrations (PNCs). METHODS: We conducted a longitudinal repeated-measure study among 78 participants with a 24-h continuous ambulatory Holter electrocardiographic recorder in Shanghai, China, from January 2015 to June 2019. Linear mixed-effects models were employed to evaluate the changes of HRV parameters associated with PNCs of 7 size ranges from 0.01 to 10 µm after controlling for environmental and individual confounders. RESULTS: On the concurrent day, decreased HRV parameters were associated with increased PNCs of 0.01-0.3 µm, and smaller particles showed greater effects. For an interquartile range increase in ultrafine particles (UFP, those < 0.1 µm, 2453 particles/cm3), the declines in very-low-frequency power, low-frequency power, high-frequency power, standard deviation of normal R-R intervals, root mean square of the successive differences between R-R intervals and percentage of adjacent normal R-R intervals with a difference ≥ 50 ms were 5.06% [95% confidence interval (CI): 2.09%, 7.94%], 7.65% (95%CI: 2.73%, 12.32%), 9.49% (95%CI: 4.64%, 14.09%), 5.10% (95%CI: 2.21%, 7.91%), 8.09% (95%CI: 4.39%, 11.65%) and 24.98% (95%CI: 14.70%, 34.02%), respectively. These results were robust to the adjustment of criteria air pollutants, temperature at different lags, and the status of heart medication. CONCLUSIONS: Particles less than 0.3 µm (especially UFP) may dominate the acute effects of particulate air pollution on cardiac autonomic dysfunction.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/estadística & datos numéricos , Exposición a Riesgos Ambientales/estadística & datos numéricos , Material Particulado/análisis , Contaminación del Aire/análisis , China , Femenino , Cardiopatías , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Tamaño de la Partícula , Temperatura
19.
Food Chem ; 346: 128970, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33422919

RESUMEN

Cedarwood essential oil (CEO) has the effect of anti-inflammatory and anti-bacteria. However, the application of this essential oil is limited due to its strong volatility and poor water solubility. To address this issue, two types of oil-in-water CEO emulsions including CEO nanoemulsion (CEO-NE) and CEO Pickering emulsion (CEO-PE) were prepared. CEO-NE with 5% surfactant, had a smaller particle size (135.14 ± 1.1 nm) and higher absolute zeta potential value (32.75 mV) compared with CEO-PE (1% starch) which particle size was 626.21 ± 6.05 nm, zeta potential was 27.58 mV. The stability of CEO-NE and CEO-PE were tested by multiple light scattering, results showed that Turbiscan Stability Index (TSI) value of CEO-NE was much lower than that of CEO-PE. CEO-NE and CEO-PE exerted higher free radical scavenging activities, iron reducing power and antibacterial ability than CEO itself. These results indicated that emulsification is a feasible method to extend application of CEO.


Asunto(s)
Antibacterianos/química , Antioxidantes/química , Emulsiones/química , Aceites Volátiles/química , Antibacterianos/farmacología , Cedrus/metabolismo , Enterobacteriaceae/efectos de los fármacos , Cromatografía de Gases y Espectrometría de Masas , Tamaño de la Partícula , Reología , Resistencia al Corte , Temperatura
20.
Nano Lett ; 21(2): 1017-1024, 2021 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-33444028

RESUMEN

Bioaerosols, including infectious diseases such as COVID-19, are a continuous threat to global public safety. Despite their importance, the development of a practical, real-time means of monitoring bioaerosols has remained elusive. Here, we present a novel, simple, and highly efficient means of obtaining enriched bioaerosol samples. Aerosols are collected into a thin and stable liquid film by the unique interaction of a superhydrophilic surface and a continuous two-phase centrifugal flow. We demonstrate that this method can provide a concentration enhancement ratio of ∼2.4 × 106 with a collection efficiency of ∼99.9% and an aerosol-into-liquid transfer rate of ∼95.9% at 500 nm particle size (smaller than a single bacterium). This transfer is effective in both laboratory and external ambient environments. The system has a low limit of detection of <50 CFU/m3air using a straightforward bioluminescence-based technique and shows significant potential for air monitoring in occupational and public-health applications.


Asunto(s)
Aerosoles , Bacterias/aislamiento & purificación , Monitoreo del Ambiente/instrumentación , Monitoreo del Ambiente/métodos , Microbiología del Aire , Biomasa , Límite de Detección , Luminiscencia , Nanopartículas , Tamaño de la Partícula , Salud Pública , Propiedades de Superficie , Temperatura
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA