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1.
J Comput Assist Tomogr ; 45(1): 84-92, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33475316

RESUMO

OBJECTIVE: This study aimed to assess the potential of an Ag additional filter attached to the bow tie filter of a computed tomography (CT) scanner to reduce the radiation dose in CT localizer radiography. METHODS: Radiation doses in CT localizer radiography with Cu and Ag additional filters were evaluated based on dose measurements and Monte Carlo simulations. Image quality evaluations of an adult torso phantom were performed, and the automatic exposure control performance was evaluated in terms of the water-equivalent thickness estimated from CT localizer radiographs. RESULTS: With the Ag additional filter, effective doses were approximately 72% to 75% lower than those with the Cu additional filter. The image quality and water-equivalent thickness with the Ag additional filter were similar to those with the Cu additional filter. CONCLUSIONS: The Ag additional filter helped significantly reduce radiation doses in CT localizer radiography while maintaining image quality and performance.


Assuntos
Prata/efeitos adversos , Tomografia Computadorizada por Raios X/instrumentação , Tronco/diagnóstico por imagem , Adulto , Cobre/efeitos adversos , Desenho de Equipamento , Humanos , Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador
2.
Int J Nanomedicine ; 15: 10425-10434, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33376330

RESUMO

Purpose: The public fear associated with the novel coronavirus (SARS-CoV-2) pandemic has triggered recently a significant proliferation of supplements touted as potential cures against bacteria and viruses. Colloidal silver has particularly benefited from this rush given its empirically and scientifically documented anti-bacterial and anti-viral actions. The lack of standards in the unregulated supplements industry remains a major roadblock in evaluating the quality and consistency of marketed products or assessing the accuracy of the information provided by manufacturers. This study is the first scientifically rigorous attempt to evaluate commercial silver colloidal products offered for sale on the internet. Methods: Fourteen of the most popular colloidal silver products purchased from Amazon (www.amazon.com) were evaluated using state-of-the-art analytical techniques widely accepted as gold standards for investigating the properties (size, shape) and the dispersion of silver nanoparticles. Results: Commercial samples were analysed using UV-Vis, FE-SEM and AAS techniques. In general, the Ag concentration was very close to those claimed by the manufacturer. The colorless product shows no absorbance in the UV-Vis analysis. The FESEM and STEM images confirmed the conclusions of the UV-Vis analysis. Conclusion: The results of this evaluation show clearly that 70% of the commercial products evaluated contain only ionic silver. Despite the evidence showing that silver nanoparticles are not present, eight of these products are promoted by the manufacturers as 'colloidal silver'. Considering the extensive scientific research showing major differences between silver ionic and silver nanoparticles in terms of mechanisms of action, efficacy and safety, it is clear that this misrepresentation impacts the consumers and must be addressed. This study serves as blueprint for a scientific protocol to be followed by manufacturers for characterizing their silver supplements.


Assuntos
Antibacterianos/química , Prata/química , Antibacterianos/efeitos adversos , Antibacterianos/farmacologia , Humanos , Nanopartículas Metálicas/química , Segurança , Prata/efeitos adversos , Prata/farmacologia
3.
J Med Vasc ; 45(4): 177-183, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32571557

RESUMO

OBJECTIVE: To evaluate the short and long-term results of in situ prosthetic graft treatment using rifampicin-soaked silver polyester graft in patients with aortic infection. MATERIAL AND METHOD: All the patients surgically managed in our center for an aortic infection were retrospectively analyzed. The primary endpoint was the intra-hospital mortality, secondary outcomes were limb salvage, persistent or recurrent infection, prosthetic graft patency, and long-term survival. RESULTS: From January 2004 to December 2015, 18 consecutive patients (12 men and 6 women) were operated on for aortic infection. Six mycotic aneurysms and 12 prosthetic infections, including 8 para-entero-prosthetic fistulas, were treated. In 5 cases, surgery was performed in emergency. During the early postoperative period, we performed one major amputation and two aortic infections were persistent. Intra-hospital mortality was 27.7%. The median follow-up among the 13 surviving patients was 26 months. During follow-up, none of the 13 patients presented reinfection or bypass thrombosis. CONCLUSION: This series shows that in situ revascularization with rifampicin-soaked silver polyester graft for aortic infection have results in agreement with the literature in terms of intra-hospital mortality with a low reinfection rate.


Assuntos
Aneurisma Infectado/cirurgia , Antibacterianos/administração & dosagem , Aneurisma Aórtico/cirurgia , Implante de Prótese Vascular/instrumentação , Prótese Vascular , Poliésteres , Infecções Relacionadas à Prótese/cirurgia , Rifampina/administração & dosagem , Prata , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Aneurisma Infectado/diagnóstico por imagem , Aneurisma Infectado/microbiologia , Aneurisma Infectado/mortalidade , Antibacterianos/efeitos adversos , Aneurisma Aórtico/diagnóstico por imagem , Aneurisma Aórtico/microbiologia , Aneurisma Aórtico/mortalidade , Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/mortalidade , Feminino , França , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Poliésteres/efeitos adversos , Desenho de Prótese , Infecções Relacionadas à Prótese/diagnóstico por imagem , Infecções Relacionadas à Prótese/microbiologia , Infecções Relacionadas à Prótese/mortalidade , Estudos Retrospectivos , Rifampina/efeitos adversos , Fatores de Risco , Prata/efeitos adversos , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
4.
Int J Nanomedicine ; 15: 2555-2562, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368040

RESUMO

Nanotechnology has recently emerged as a rapidly growing field with numerous biomedical science applications. At the same time, silver has been adopted as an antimicrobial material and disinfectant that is relatively free of adverse effects. Silver nanoparticles possess a broad spectrum of antibacterial, antifungal and antiviral properties. Silver nanoparticles have the ability to penetrate bacterial cell walls, changing the structure of cell membranes and even resulting in cell death. Their efficacy is due not only to their nanoscale size but also to their large ratio of surface area to volume. They can increase the permeability of cell membranes, produce reactive oxygen species, and interrupt replication of deoxyribonucleic acid by releasing silver ions. Researchers have studied silver nanoparticles as antimicrobial agents in dentistry. For instance, silver nanoparticles can be incorporated into acrylic resins for fabrication of removable dentures in prosthetic treatment, composite resin in restorative treatment, irrigating solution and obturation material in endodontic treatment, adhesive materials in orthodontic treatment, membrane for guided tissue regeneration in periodontal treatment, and titanium coating in dental implant treatment. Although not all authorities have acknowledged the safety of silver nanoparticles, no systemic toxicity of ingested silver nanoparticles has been reported. A broad concern is their potential hazard if they are released into the environment. However, the interaction of nanoparticles with toxic materials and organic compounds can either increase or reduce their toxicity. This paper provides an overview of the antibacterial use of silver nanoparticles in dentistry, highlighting their antibacterial mechanism, potential applications and safety in clinical treatment.


Assuntos
Antibacterianos/farmacologia , Odontologia , Nanopartículas Metálicas/química , Prata/farmacologia , Humanos , Nanopartículas Metálicas/efeitos adversos , Nanotecnologia , Prata/efeitos adversos
5.
Sci Rep ; 10(1): 3845, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32123221

RESUMO

Plants that inhabit Antarctica have raised scientific interest due to their resilience to climate change, abiotic tolerance mechanisms and potential biological applications. In vitro propagation is useful for conservation, genetic material availability of these species and avoiding mass collection in their habitat. In vitro culture protocols for the native plants Colobanthus quitensis and Deschampsia antarctica and the non-native Juncus bufonius have been affected by endophytic microorganisms that proliferate when introduced to tissue cultures. This study evaluated the microbicidal and phytotoxic effect of calcium hypochlorite (Ca(ClO)2), silver nitrate (AgNO3) and silver nanoparticles (AgNPs), and their use at different concentrations for different time periods. The Ca(ClO)2 at 100 mg mL-1 showed the best microbial contamination control in D. antarctica (applied for 20 min) and for the three C. quitensis populations (applied for 15 min). In J. bufonius, AgNO3 at 10 mg mL-1 for 10 min reduced the microbial growth, but oxidative damage was generated. AgNPs did not prevent contamination or have adverse effects on tissues. Survival plantlets from each treatment, population or species were effectively introduced to the tissue culture and their propagation was successful. These results constitute a fundamental advance for the introduction, propagation and conservation of Antarctic species and their use in scientific research.


Assuntos
Regiões Antárticas , Anti-Infecciosos/efeitos adversos , Conservação dos Recursos Naturais/métodos , Desinfecção/métodos , Espécies Introduzidas , Compostos de Cálcio/efeitos adversos , Relação Dose-Resposta a Droga , Ecossistema , Nanopartículas Metálicas/efeitos adversos , Prata/efeitos adversos , Prata/química , Nitrato de Prata/efeitos adversos
6.
Int J Nanomedicine ; 15: 633-645, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32099356

RESUMO

Background: With the increased application of Silver nanoparticles (AgNP), its potential concerns to the health of human beings remain to be defined. This study aims to explore the harmful effects of AgNP on lung tissue in animals and to examine the mechanisms of protection achieved by sodium selenite. Methods: Sprague-Dawley(SD) rats were exposed to AgNP (200 µL,1mg/mL) through a single intratracheal instillation. Sodium selenite (0.2mg/kg) was i.p. injected. Malondialdehyde (MDA) and glutathione (GSH) were measured using a spectrophotometer. Histological outcomes and ultrastructural changes were assessed by hematoxylin and eosin (HE) staining and electronic microscopy. Caspases and mitochondrial fission and fusion markers were measured by Western blotting. Results: The histopathologic findings showed that AgNP significantly increased the thickness of alveolar septa, accumulation of macrophage, and the formation of pulmonary bullae and pulmonary consolidation. Ultrastructural studies showed localization of AgNP inside the mitochondria, hyperplasia and vacuolation of type I and type II alveolar cells, lysis of osmiophilic lamellar bodies, and swollen of the mitochondria. AgNP elevated MDA and reduced GSH levels. AgNP activated caspases-3, increased mitochondrial fission markers Dynamin-related protein 1 (Drp1) and phospho-Drp1(p-Drp1), and decreased fusion proteins optic atrophy 1 (Opa1) and mitofusins 2 (Mfn2). Treatment with sodium selenite for 7 days corrected the AgNP-caused alterations in morphological, ultrastructural, oxidative stress, caspase-3 activation and mitochondrial dynamic imbalance. Conclusion: We conclude that the exposure of AgNP causes lung tissue damage by enhances oxidative stress, activates caspases-3, and triggers mitochondrial dynamic imbalance towards fission. Sodium selenite effectively detoxifies the AgNP-induced damage to the lung tissue by preventing the above alterations.


Assuntos
Pulmão/efeitos dos fármacos , Nanopartículas Metálicas/efeitos adversos , Dinâmica Mitocondrial/efeitos dos fármacos , Prata/efeitos adversos , Selenito de Sódio/farmacologia , Animais , Caspase 3/metabolismo , Morte Celular/efeitos dos fármacos , Dinaminas/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Glutationa/metabolismo , Pulmão/metabolismo , Pulmão/patologia , Masculino , Malondialdeído/metabolismo , Nanopartículas Metálicas/química , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Proteínas Mitocondriais/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Ratos Sprague-Dawley , Prata/química
7.
Bull Entomol Res ; 110(3): 309-320, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31559940

RESUMO

Nanosilver is an environment-friendly, harmless alternative of traditional disinfectants which can be potentially applied in the sericulture industry. However, the effects of nanosilver on the intestinal bacterial community of the silkworms (Bombyx mori L.) are unclear. In this study, Illumina MiSeq high-throughput sequencing technology was used to assess the intestinal bacterial community in both male and female silkworms while treated with different concentrations of nanosilver. We found that nanosilver significantly influenced the composition of silkworm intestinal bacterial community on the different taxonomic levels. Most conspicuously, the abundance of Firmicutes was increased by the treatment of 20 mg L-1 nanosilver but decreased by that of 100 mg L-1 nanosilver at the phylum level. The same trend was observed in Bacilli at the class level and in Enterococcus at the genus level. In some extreme cases, application of nanosilver eliminated the bacterium, e.g., Brevibacillus, but increased the population of several other bacteria in the host intestine, such as Blautia, Terrisporobacter, Faecalibacterium, and some bacteria could only be found in nanosilver treatment groups, e.g., Dialister. In addition, although nanosilver generally showed negative effects on the cocooning rate in a dose-dependent manner, we found that 20 mg L-1 nanosilver treatment significantly increased the body weight of silkworms and did not show negative effects on the survival rate. These results indicated that the intestinal bacteria community of silkworm larvae was significantly changed after nanosilver treatment which might consequently influence host growth and development.


Assuntos
Bombyx/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Nanopartículas Metálicas/uso terapêutico , Prata/farmacologia , Animais , Bactérias/classificação , Bactérias/genética , Bombyx/efeitos dos fármacos , Bombyx/crescimento & desenvolvimento , Desinfetantes/efeitos adversos , Desinfetantes/farmacologia , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Larva/efeitos dos fármacos , Larva/microbiologia , Masculino , Nanopartículas Metálicas/efeitos adversos , Análise de Sequência de DNA , Prata/efeitos adversos
8.
J Oncol Pharm Pract ; 26(1): 212-215, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30854923

RESUMO

We report a case of acute myeloid leukemia with complex cytogenetic abnormalities suggestive of preexisting myelodysplastic syndrome in a patient with habitual ingestion of colloidal silver as nutritional supplement for over 10 years and the medical literature is reviewed.


Assuntos
Aberrações Cromossômicas/induzido quimicamente , Leucemia Mieloide Aguda/induzido quimicamente , Prata/efeitos adversos , Idoso , Suplementos Nutricionais/efeitos adversos , Humanos , Leucemia Mieloide Aguda/genética , Masculino
9.
Sci Total Environ ; 692: 233-239, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31349164

RESUMO

Because of their biocide properties, silver nanoparticles (AgNPs) are present in numerous consumer products. The biocidal properties of AgNPs are due to both the interactions between AgNP and cell membranes and the release of dissolved silver (Ag+). Recent studies emphasized the role of different nanoparticle coatings in complexing and storing Ag+. In this study, the availability of dissolved silver in the presence of algae was assessed for three AgNPs with different silver contents (59%, 34% and 7% of total Ag), silver core sizes and casein shell thicknesses. The impact of ionic silver on the photosynthetic yield of Chlamydomonas reinhardtii was used as a proxy to estimate the amount of ionic silver toxically active during in vivo assays. The results showed that cysteine, a strong silver ligand, mitigated the toxicity of AgNPs in all cases, demonstrating the key role of Ag+ in this toxicity. The results showed that the AgNPs presenting an intermediate level of silver (34%) were 10 times more effective in terms of total mass (EC50 ten times smaller) than those presenting more (59%) or less (7%) silver. The higher toxicity was due to the higher release of Ag+ under biotic conditions due to the high surface/mass ratio of the nanoparticle silver core. Protein shells played a minor role in altering the availability of Ag+, probably acting as intermediate reservoirs. This study highlighted the utility of a very sensitive biological endpoint (i.e., algal photosynthesis) for the optimization of ionic silver delivery by nanomaterials.


Assuntos
Chlamydomonas reinhardtii/efeitos dos fármacos , Nanopartículas Metálicas/efeitos adversos , Fotossíntese/efeitos dos fármacos , Prata/efeitos adversos , Disponibilidade Biológica , Chlamydomonas reinhardtii/metabolismo , Cisteína/administração & dosagem , Relação Dose-Resposta a Droga , Íons/efeitos adversos , Substâncias Protetoras/administração & dosagem
11.
Chem Res Toxicol ; 32(6): 952-968, 2019 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-31124663

RESUMO

Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. AgNP toxicity in the respiratory system is well characterized, but few in vitro or in vivo studies have evaluated the effects of interactions between host genetic and acquired factors or gene × environment interactions (G × E) on AgNP toxicity in the respiratory system. The primary goal of this article is to review host genetic and acquired factors identified across in vitro and in vivo studies and prioritize those necessary for defining exposure limits to protect all populations. The impact of these exposures and the work being done to address the current limited protections are also discussed. Future research on G × E effects on AgNP toxicity is warranted and will assist with informing regulatory or recommended exposure limits that enforce special protections for all populations to AgNP exposures in occupational settings.


Assuntos
Interação Gene-Ambiente , Nanopartículas Metálicas/efeitos adversos , Sistema Respiratório/efeitos dos fármacos , Prata/efeitos adversos , Animais , Humanos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade
12.
Am J Case Rep ; 20: 730-734, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31118408

RESUMO

BACKGROUND Leukocytoclastic vasculitis is a disease of the small vessels and is uncommon in children. In this case report, we present an adolescent case of leukocytoclastic vasculitis associated with the ingestion of colloidal silver, a naturopathic drug. This report highlights the rarity of the patient's presentation and inducing agent. CASE REPORT A 19-year-old female presented in the Emergency Department with severe rash on the face, and neck, and then continued to spread in a craniocaudal fashion during the day of presentation to involve trunk, back, upper and lower extremities. There was no recent travel, no pets and a negative family history for rheumatologic or autoimmune diseases. Her home medications included colloidal silver for "internal cleansing" for 4 weeks prior to Emergency Department presentation. Once the clinicians were aware of the continued ingestion of colloidal silver, the patient was advised to discontinue the drug. The patient was started on methylprednisolone with preliminary diagnosis of vasculitis, as well as concurrent therapy with colchicine. The rash was noted to be receding from the face within 24 hours. Over a hospital course of 5 days, the patient's rash and pruritus continued to slowly improve. CONCLUSIONS The ingestion of a naturopathic drug, colloidal silver, caused vast leukocytoclastic vasculitis in our patient warranting hospitalization due to the extent of the disease. The symptoms resolved after discontinuation of colloidal silver ingestion. Due to unknown safe ingestion concentrations and potential side effects, use of colloidal silver should be discouraged.


Assuntos
Naturopatia/efeitos adversos , Prata/efeitos adversos , Vasculite Leucocitoclástica Cutânea/induzido quimicamente , Vasculite Leucocitoclástica Cutânea/diagnóstico , Feminino , Humanos , Vasculite Leucocitoclástica Cutânea/terapia , Adulto Jovem
13.
Int J Nanomedicine ; 14: 1687-1703, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30880973

RESUMO

Background: No systematic investigations have been conducted to assess the lung burden imposed by the chronic inhalation of silver nanoparticles (AgNPs) emitted by spray products. Objective: The objective of this study was to formulate a study framework that integrates a probabilistic risk assessment scheme with a mechanistic lung burden model for the estimation of health risks associated with the long-term inhalation of AgNP-containing spray products. Materials and methods: A compartmentalized physiologically based alveolar deposition (PBAD) model was used to estimate AgNP lung burden. Dose-response relationships were established using nanotoxicity data sets obtained from rats (as a model organism). Weibull model-based thresholds of AgNP lung burden based on neutrophil-elevated inflammation bio-markers were estimated from Hill-based exposure-response relationships. Finally, the risks of lung disease posed by various AgNP-containing spray products were assessed. Results: Conservative thresholds for the prevention of pulmonary disease were estimated as follows (mean ± SE): 34 nm AgNPs (0.32±0.22 mg) and 60 nm AgNPs (1.08±0.64 mg). Our results indicate that the risk probability was ~0.5 that the hazard quotient (HQ) estimates of deodorant with a count median diameter (CMD) ≈30 nm exceeded 1. The primary risk posed by AgNPs is transferred from the interstitial region to lymph nodes. Under the condition of 50% risk probability, the 97.5 percentile of HQ for the spray products were as follows: CMD ≈30 nm (~3.4) and CMD ≈60 nm (~1.1). Conclusion: Our application of the proposed risk assessment scheme to the results obtained in an in vivo animal model proved highly effective in elucidating the relationship between the characteristics of metallic NP-containing spray products and their corresponding toxicity. The integration of the proposed PBAD model with a risk assessment framework enables the rapid assessment of risk posed by spray products containing metallic NPs over various time scales.


Assuntos
Aerossóis/efeitos adversos , Exposição Ambiental/análise , Pneumopatias/etiologia , Nanopartículas Metálicas/efeitos adversos , Medição de Risco , Prata/efeitos adversos , Administração por Inalação , Animais , Humanos , Pulmão/metabolismo , Modelos Teóricos , Tamanho da Partícula , Ratos
14.
Sci Total Environ ; 663: 351-360, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30716625

RESUMO

The present study aims to evaluate the effects of copper and silver alone or along with a moderate temperature increase on embryonic development, DNA integrity and target gene expression levels in early life stages of Mytilus galloprovincialis. For this purpose, upon fertilized embryos were exposed to a sub-lethal concentration of Cu (9.54 µg/L), Ag (2.55 µg/L) and to the mixture of the two metals (Cu (6.67 µg/L) + Ag (1.47 µg/L)) along with a temperature gradient (18, 20 and 22 °C). In all experiments, larvae were exposed to stressors for 48 h except for those designed to DNA damage analysis exposed only for 24 h (before shell formation).Our results showed a significant increase in the percentage of malformed D-larvae (p < 0.05) with increasing temperature and exposure to silver and copper alone or in a mixture. Moreover, metal toxicity increased significantly (p < 0.05) with the temperature rise. Genotoxicity was evaluated using classic and modified with Formamidopyrimidine DNA glycosylase (Fpg) Comet assay. Results suggest that co-exposure to metals and temperature significantly increased DNA damage on mussel larvae with a more accentuated oxidative damage. A significant transcription modulation was observed for genes involved in DNA repair and DNA replication (p53, DNA ligase II and topoisomerase II) when larvae are exposed to a single stressor. However, in the case of multiple stresses, caspase involved in the cell apoptosis pathway was overexpressed. Our study suggests that mussel larvae exposed to a moderate increase in temperature may have a compromised ability to defend against genotoxicity. This is particularly relevant in the context of global warming and thermal pollution.


Assuntos
Cobre/efeitos adversos , Temperatura Alta/efeitos adversos , Mytilus/efeitos dos fármacos , Prata/efeitos adversos , Animais , Apoptose/genética , Ensaio Cometa , Reparo do DNA/genética , Embrião não Mamífero/efeitos dos fármacos , Desenvolvimento Embrionário/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Mytilus/embriologia , Mytilus/crescimento & desenvolvimento , Mytilus/fisiologia , Reação em Cadeia da Polimerase em Tempo Real
15.
Mol Metab ; 22: 1-11, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30737105

RESUMO

OBJECTIVE: Obesity is a complex chronic disease of high prevalence worldwide. Multiple factors play integral roles in obesity development, with rising interest focusing on the contribution of environmental pollutants frequent in modern society. Silver nanoparticles (AgNPs) are widely used for bactericidal purpose in various applications in daily life. However, their potential toxicity and contribution to the obesity epidemic are not clear. METHODS: Beige adipocytes are newly discovered adipocytes characterized by high thermogenic and energy dissipating capacity upon activation and the "browning" process. In the present study, we assess the impact of AgNPs exposure on beige adipocytes differentiation and functionality both in vitro and in vivo. We also systematically investigate the influence of AgNPs on adiposity and metabolic performance in mice, as well as the possible underlying molecular mechanism. RESULTS: The results showed that, independent of particle size, AgNPs inhibit the adipogenic, mitochondrial, and thermogenic gene programs of beige adipocytes, thus suppressing their differentiation ability, mitochondrial activity, and thermogenic response. Importantly, exposure to AgNPs in mice suppresses browning gene programs in subcutaneous fat, leading to decreased energy expenditure and increased adiposity in mice. Mechanistically, we found that AgNPs increase reactive oxidative species (ROS) levels and specifically activate MAPK-ERK signaling in beige adipocytes. The negative impacts of AgNPs on beige adipocytes can be ameliorated by antioxidant or ERK inhibitor FR180204 treatment. CONCLUSIONS: Taken together, these results revealed an unexpected role of AgNPs in promoting adiposity through the inhibition of beige adipocyte differentiation and functionality, possibly by disrupting ROS homeostasis and ERK phosphorylation. Future assessments on the health risk of AgNPs applications and their safe dosages are warranted.


Assuntos
Adipócitos Bege/efeitos dos fármacos , Adiposidade/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/farmacologia , Adipócitos Bege/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/efeitos adversos , Camundongos , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Prata/administração & dosagem , Prata/efeitos adversos , Prata/química
16.
Artigo em Inglês | MEDLINE | ID: mdl-30625980

RESUMO

Silver Nanoparticles (AgNPs), an epitome of nanotechnology, appear in everyday products such as water filters, printer ink, toothpaste, food packaging and cosmetics mostly due to their bactericidal properties. Given this high level of public exposure, the safety of AgNPs has never been fully established. The unsafe use of AgNPs could pose a real threat, not only to public health but also to economic growth in many industries. In this paper, we tested the effect of AgNPs on memory, learning, social behaviour and motor function of BALB/C mice. Outcomes of the present study suggested an impairment of these functions in AgNPs treated groups. Overall, obtained data support the evidence that the systemic exposure to AgNPs may result in alteration of the cerebral cognition and warrants further consideration on the impact of the AgNPs on human health with respect to their potential neurotoxicity.


Assuntos
Comportamento Animal/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Aprendizagem/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/efeitos adversos , Comportamento Social , Animais , Antibacterianos/efeitos adversos , Cognição/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Camundongos Endogâmicos BALB C
18.
Sci Total Environ ; 660: 459-467, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30640113

RESUMO

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. However, findings on the toxic effects of the AgNPs are still limited. This paper reports an investigation on the cytotoxic and genotoxic potential of the AgNPs on root cells of Allium cepa. Germination (GI), root elongation (REI), mitotic (MI), nuclear abnormality (NAI), and micronucleus index (MNI) were determined for seeds exposed to various AgNPs diameters (10, 20, 51, and 73 nm) as well as to the silver bulk (AgBulk) (micrometer-size particles) at the concentration of 100 mg·L-1. Transmission electron microscopy (TEM) provided the particle size distribution, while dynamic light scattering (DLS) was used to get the hydrodynamic size, polydispersity index, and zeta potential of the AgNPs. Laser-induced breakdown spectroscopy (LIBS) and inductively coupled plasma/optical emission spectrometry (ICP OES) were applied for quantifying the AgNPs content uptake by roots. Silver dissolution was determined by dialysis experiment. Results showed that the AgNPs penetrated the roots, affecting MI, GI, NAI, and MNI in meristematic cells. Changes in these indicators were AgNPs diameter-dependent so that cytotoxic and genotoxic effects in Allium cepa increased with the reduction of the particle diameter. The results also revealed that the AgNPs were the main responsible for the cytotoxicity and genotoxicity since negligible silver dissolution was observed.


Assuntos
Allium/efeitos dos fármacos , Citotoxinas/efeitos adversos , Meristema/efeitos dos fármacos , Nanopartículas Metálicas/efeitos adversos , Mutagênicos/efeitos adversos , Prata/efeitos adversos , Testes de Mutagenicidade , Tamanho da Partícula , Raízes de Plantas/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos
19.
Microbiologyopen ; 8(4): e00698, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30079629

RESUMO

Staphylococcus aureus (S. aureus) is one of the prevalent mastitis-inducing pathogens worldwide. The resistance of S. aureus to antibiotics is a common issue for dairy farms. Recently, nanoparticles (NPs) have been used for treating antibiotic-resistant bacteria. We therefore aimed to investigate the antimicrobial effect of silver and gold NPs (AgNPs and AuNPs, respectively) and the resistance developed by S. aureus as well as the toxic effects of both NPs in rats. We used 198 S. aureus strains to determine the antibacterial effects of AgNPs and AuNPs. The microdilution method was used to establish the minimum inhibitory concentrations (MICs) of both NPs. To induce resistance, 20 S. aureus strains were passaged 10 times in broth medium with sublethal doses of NPs and an additional 10 times without NPs to examine the stability of resistance. Histopathology was performed after oral administration to the rats with the study doses of 0.25, 0.5, 1, and 2 mg/kg of NPs for 30 days. The MICs of 10-nm AgNPs, 20-nm AgNPs, 10-nm AuNPs, and 20-nm AuNPs against S. aureus were 14.70 ± 1.19 µg/ml, 9.15 ± 0.13 µg/ml, 24.06 ± 2.36 µg/ml, and 18.52 ± 1.26 µg/ml, respectively. Most strains developed strong resistance when treated with 20-nm or 10-nm AgNPs, whereas only two strains were resistant to 10-nm AuNPs and three strains to 20-nm AuNPs. No cross-resistance between NPs and various antibiotics was identified in any of the adapted S. aureus strains. Organ histopathology revealed that 0.25, 0.5, and 1 mg/kg doses of AgNPs and AuNPs were not toxic to rat tissue. In contrast, a higher dose (2 mg/kg) of NPs impaired all organs tested. This study demonstrates the antibacterial effects of NPs. S. aureus strains develop resistance less frequently against AuNPs than AgNPs, and neither AuNPs nor AgNPs was toxic to rats at low doses.


Assuntos
Antibacterianos/efeitos adversos , Ouro/efeitos adversos , Mastite/microbiologia , Nanopartículas Metálicas/toxicidade , Prata/efeitos adversos , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Antibacterianos/química , Farmacorresistência Bacteriana , Feminino , Ouro/química , Humanos , Masculino , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana , Ratos , Prata/química , Staphylococcus aureus/genética , Staphylococcus aureus/fisiologia
20.
Adv Clin Exp Med ; 28(3): 299-305, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30170485

RESUMO

BACKGROUND: Silver nanoparticles (AgNPs) are more often used in various products, and consequently the potential deleterious effects associated with exposure to them are of concern. Several lines of evidence have demonstrated that the toxicity of AgNPs affects different organs and leads to some side effects, including weight loss, inflammation and cell death. OBJECTIVES: The aim of this study was to evaluate the effect of different concentrations of AgNPs on sperm parameters and testicular histology. MATERIAL AND METHODS: In the present study, 28 male adult Wistar rats were categorized into a control group and 3 experimental groups (AgNP-1, AgNP-2 and AgNP-3), intraperitoneally (i.p.) receiving 30, 125 and 300 mg/kg of AgNPs, respectively. Twenty-eight days after injection the epididymes and the testes of each rat were dissected in order to evaluate sperm parameters, sperm chromatin integrity and histomorphometric changes in the testicular tissue. RESULTS: The results showed a significant decrease in sperm count (p < 0.0001), vitality (p < 0.05) and morphology changes (p < 0.001) in the group receiving 300 mg/kg of AgNPs compared to the control group. A significant decrease was also observed in the number of spermatogonia, Sertoli and Leydig cells in the AgNP-2 and AgNP-3 groups (p < 0.05). The evaluation of sperm chromatin did not show any significant differences among the experimental groups (p > 0.05). CONCLUSIONS: The data showed some dose-dependent adverse effects of AgNPs on sperm and seminiferous tubules. More experimental investigations are necessary to draw better conclusions regarding the safety of nanoparticles (NPs) on the male reproduction system.


Assuntos
Dano ao DNA , Genitália Masculina/efeitos dos fármacos , Nanopartículas Metálicas/efeitos adversos , Prata/efeitos adversos , Animais , DNA , Genitália Masculina/metabolismo , Masculino , Ratos , Ratos Wistar , Espermatozoides/efeitos dos fármacos , Espermatozoides/fisiologia , Testículo/efeitos dos fármacos , Testículo/metabolismo
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