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1.
Andrologia ; 52(1): e13426, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31670414

RESUMO

There is a current interest from the food packaging, biomedical and agricultural sectors in hybrid materials formed from clays and natural polymeric compounds. However, research investigating the toxicity of vermiculite-cellulose nanocrystal (VERN) hybrid on the testes of Wistar rats is rare. Twenty rats, divided into control and treatment groups, were orally administered distilled water, 5, 10, and 20 mg/kg bw VERN daily for two consecutive weeks. At the termination of experiments, the testicular organo-somatic index, superoxide dismutase, catalase, and gamma-glutamyl transferase activities were not significantly changed by VERN relative to the controls. Contrarily, myeloperoxidase, glutathione peroxidase, and malondialdehyde levels were depleted in the testes of treated rats. Moreso, VERN increased follicle-stimulating and luteinizing hormones, and decreased testosterone levels at the 20 mg/kg dose. Histology of the testes revealed healthy looking Leydig cells at the doses of 5 and 10 mg/kg VERN. Overall, these results indicate that oral exposure of VERN was not overly deleterious to the redox and structural histoarchitecture in the testes of rats.


Assuntos
Silicatos de Alumínio/toxicidade , Celulose/toxicidade , Nanocompostos/toxicidade , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Administração Oral , Silicatos de Alumínio/administração & dosagem , Animais , Catalase/análise , Catalase/metabolismo , Celulose/administração & dosagem , Hormônio Foliculoestimulante/sangue , Glutationa Peroxidase/análise , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Hormônio Luteinizante/sangue , Masculino , Modelos Animais , Nanocompostos/administração & dosagem , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Superóxido Dismutase/análise , Superóxido Dismutase/metabolismo , Testículo/enzimologia , Testosterona/sangue , Testes de Toxicidade Aguda
2.
Environ Sci Pollut Res Int ; 26(21): 22061-22068, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31144179

RESUMO

Human is exposed to traces of aluminum silicate (AlS), i.e., cosmetics, pesticides. Accumulation of aluminum compounds including AlS is associated with neuropathological diseases, e.g., Alzheimer's disease. The aim of the current study is to investigate the neuroprotective effects of propolis extracts in AlS-induced cerebellum intoxication in rats. Forty adult rats were randomly divided into four groups (n = 10). The first group served as a control; the second group treated with 200 ml propolis/kg bwt. every other day by stomach gavage tube, third group was intraperitoneally injected with AIS (20 mg/kg) twice a week for 8 weeks, and the fourth group received propolis extract and AIS. At the end of 8 weeks, the cerebellum was harvested for further ultrastructure, histological, and histochemical investigations. Using electron microscopy, the ultrastructure of the cerebellar cortex of AlS intoxicated rats showed Purkinje cells with an irregular euchromatic nucleus and extremely increased invagination of the nuclear envelope. In addition, the cytoplasm revealed numerous damaged mitochondria (> 20%) as well as swollen lysosomes (> 40%) compared to controls. These AlS-related ultrastructure changes were to some extent normalized to < 10% and < 30% in case of mitochondria and lysosomes, respectively, if rats were co-treated with propolis extract. Further, histopathological examination showed that AlS-exposed rats revealed abnormal Purkinje cells with irregular size and shrank shape, evidence of pre-necrotic stage in the form of nuclear pyknosis, and condensed and frequent darkly stained cells in cerebellar layers. However, propolis extract co-administration reversed from 35 to 25% (p < 0.05) these alterations. The carbohydrate and protein contents were reduced in case of AlS treatment and surprisingly propolis co-treatment was able to rescue these neurotoxic effects. Propolis extract might have neuroprotective effects against AIS-induced toxicity. Further studies are required to identify the mechanism of the pharmacological action and optimal settings for medical testing of propolis extract.


Assuntos
Silicatos de Alumínio/toxicidade , Cerebelo/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Própole/farmacologia , Compostos de Alumínio , Animais , Egito , Humanos , Masculino , Síndromes Neurotóxicas , Ratos
3.
Toxicol Appl Pharmacol ; 361: 127-136, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-30077661

RESUMO

We analyzed the mesothelioma mortality in cohorts of workers exposed to crocidolite, amosite, and chrysotile to estimate asbestos fiber potency for mesothelioma, using the method of Hodgson and Darnton (2000). We relied on the original 17 cohort studies in their analysis, along with 3 updates of those studies and 3 new asbestos cohort studies published since 2000. We extended the analyses to examine the mesothelioma potency of tremolite in vermiculite from Libby, Montana, and for non-asbestiform elongate mineral particles (EMPs) in taconite iron ore, talc, and South Dakota gold mining. Mesothelioma potency (RMeso) was calculated as the percent of all expected deaths that were due to mesothelioma per fiber/cc-year of exposure.The RMeso was 0.0012 for chrysotile, 0.099 for amosite, and 0.451 for crocidolite: thus, the relative potency of chrysotile:amosite:crocidolite was 1:83:376, which was not appreciably different from the estimates by Hodgson and Darnton in 2000. The RMeso for taconite mining fibers was 0.069 which was slightly smaller than that for amosite. The RMeso for Libby fibers was 0.028 which was greater than that for chrysotile and less than that for amosite. Talc and gold mining EMPs were non-potent for mesothelioma. Although there are a number of methods for estimating fiber potency of asbestos and non-asbestiform EMPs, the method of Hodgson and Darnton provides a uniform method by which fiber potency can be compared across many fiber types. Our estimates of RMeso provide a useful addition to our knowledge of mesothelioma potency for different asbestos and non-asbestiform EMP fibers.


Assuntos
Poluentes Ocupacionais do Ar/toxicidade , Asbestos/toxicidade , Carcinógenos/toxicidade , Neoplasias Pulmonares/mortalidade , Mesotelioma/mortalidade , Minerais/toxicidade , Material Particulado/toxicidade , Silicatos de Alumínio/toxicidade , Amianto Amosita/toxicidade , Amiantos Anfibólicos/toxicidade , Asbesto Crocidolita/toxicidade , Asbestos Serpentinas/toxicidade , Estudos de Coortes , Humanos , Ferro/toxicidade , Neoplasias Pulmonares/etiologia , Mesotelioma/etiologia , Mineração , Exposição Ocupacional , Tamanho da Partícula , Silicatos/toxicidade , Talco/toxicidade
4.
J Agric Food Chem ; 66(11): 2925-2933, 2018 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-29470912

RESUMO

Natural halloysite (Al2Si2O5(OH)4· nH2O) nanotubes (HNT) are clay materials with hollow tubular structure and are widely applied in many fields. Many in vitro studies indicate that HNTs exhibit a high level of biocompatibility; however, the in vivo toxicity of HNTs remains unclear. In this study, the biodistribution and pulmonary toxicity of the purified HNTs in mice were investigated after intragastric administration for 30 days. HNTs have high stability in biological conditions. Oral administration of HNTs caused significant Al accumulation predominantly in the lung with relative slight effects on Si biodistribution. Oral administration of HNTs stimulated the growth of the mice at low dose (5 mg/kg BW) with no pulmonary toxicity but inhibited the mouse growth and resulted in oxidative stress and inflammation in lung at high dose (50 mg/kg BW). In addition, oral HNTs at high dose could be absorbed from the gastrointestinal tract and deposited in lung and could also induce pulmonary fibrosis.


Assuntos
Silicatos de Alumínio/metabolismo , Silicatos de Alumínio/toxicidade , Alumínio/toxicidade , Pulmão/efeitos dos fármacos , Camundongos/metabolismo , Nanotubos/toxicidade , Alumínio/metabolismo , Animais , Argila , Pulmão/metabolismo , Masculino , Camundongos/crescimento & desenvolvimento , Estresse Oxidativo , Distribuição Tecidual
5.
Environ Toxicol ; 33(6): 623-630, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29457689

RESUMO

Halloysite (Al2 Si2 O5 (OH)4 ·nH2 O) nanotubes (HNTs) are natural clay materials and widely applied in many fields due to their natural hollow tubular structures. Many in vitro studies indicate that HNTs exhibit a high level of biocompatibility, however the in vivo toxicity of HNTs remains unclear. The objective of this study was to assess the hepatic toxicity of the purified HNTs in mice via oral route. The purified HNTs were orally administered to mice at 5, 50, and 300 mg/kg body weight (BW) every day for 30 days. Oral administration of HNTs stimulated the growth of the mice at the low dose (5 mg/kg BW) with no liver toxicity, but inhibited the growth of the mice at the middle (50 mg/kg BW) and high (300 mg/kg BW) doses. In addition, oral administration of HNTs at the high dose caused Al accumulation in the liver but had no marked effect on the Si content in the organ. The Al accumulation caused significant oxidative stress in the liver, which induced hepatic dysfunction and histopathologic changes. These findings demonstrated that Al accumulation-induced oxidative stress played an important role in the oral HNTs-caused liver injury.


Assuntos
Silicatos de Alumínio/toxicidade , Alumínio/farmacocinética , Fígado/efeitos dos fármacos , Nanotubos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Administração Oral , Silicatos de Alumínio/administração & dosagem , Silicatos de Alumínio/química , Silicatos de Alumínio/farmacocinética , Animais , Argila , Dano ao DNA/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Nanotubos/química , Fatores de Tempo , Testes de Toxicidade Crônica
6.
Carbohydr Polym ; 158: 1-10, 2017 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-28024531

RESUMO

Protecting cells from toxicosis even apoptosis induced by a variety of toxic heavy metals stimulus has drawn more and more attentions. This study was designed to elucidate whether chitosan-organic rectorite (CS-OREC) composites exhibited any protective effects on altered oxidative stress parameter in PC12 cells exposed to lead ions (Pb2+). The cells were exposed to Pb2+ either alone or in combination with CS-OREC composites for designated time to evaluate the efficacy of the composites on Pb2+-induced toxicity. The MTT assay results showed that the cell viability of PC12 was remarkably decreased when exposed to Pb2+, but significantly retained after adding CS-OREC composites compared to that of the control. The beneficial effect of CS-OREC composites on cytotoxicity was related, at least in part, to its ability to protect against apoptosis in PC12 cells exposed to 50µM Pb2+. Their protective effect was also associated with the inhibitory effect on Pb2+-induced activation of Bax/Bcl-2, P-38, and caspase-3 pathways, while was independent on JNK pathway.


Assuntos
Silicatos de Alumínio/farmacologia , Quitosana/farmacologia , Chumbo/toxicidade , Minerais/farmacologia , Nanocompostos/química , Fármacos Neuroprotetores/farmacologia , Silicatos de Alumínio/química , Silicatos de Alumínio/toxicidade , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Quitosana/química , Quitosana/toxicidade , Minerais/química , Minerais/toxicidade , Nanocompostos/toxicidade , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/toxicidade , Compostos Organometálicos/toxicidade , Células PC12 , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Transdução de Sinais/efeitos dos fármacos , Proteína X Associada a bcl-2/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
7.
Chemosphere ; 154: 240-248, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27058916

RESUMO

Clay2 is an organomodified montmorillonite developed by the Technological Institute of Packaging, Transport and Logistic (ITENE) in order to improve polymeric materials used in food packaging. There is not much known on Clay2 toxic potential, particularly at DNA level, therefore it is mandatory to assess its toxicity prior to its commercialization. In the present study the human hepatoma cell line (HepG2) was exposed to non-cytotoxic concentrations of Clay2 and the genomic stability was studied with the Cytokinesis block micronucleus cytome assay, by determining the formation of micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs). Moreover, the expression of various genes involved in the mechanisms of its action using the real-time quantitative PCR was studied. The results obtained provide the evidence that Clay2 is potentially genotoxic as it increased the frequency of micronuclei. In addition it deregulated genes involved in the metabolism, immediate-early response/signaling, DNA damage and oxidative stress showing new valuable information on the cellular response to Clay2. Nonetheless, further studies are highly needed to elucidate the molecular mechanisms of clays toxicity.


Assuntos
Silicatos de Alumínio/toxicidade , Bentonita/toxicidade , Embalagem de Alimentos/métodos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos/métodos , Mutagênicos/toxicidade , Carcinoma Hepatocelular , Linhagem Celular Tumoral , Núcleo Celular , Argila , Dano ao DNA , Expressão Gênica/efeitos dos fármacos , Células Hep G2 , Humanos , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/metabolismo , Neoplasias Hepáticas , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Reação em Cadeia da Polimerase em Tempo Real
8.
Environ Toxicol Chem ; 35(10): 2503-2510, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-26918843

RESUMO

Halloysite nanotubes (HNTs) are natural nanomaterials that are biocompatible and available in large amounts at low prices. They are emerging nanomaterials with appealing properties for applications like support for metal nanoparticles (NPs). The potential environmental impacts of NPs can be understood in terms of phytotoxicity. Current research has been focusing on HNT applications in cell or animal models, while their use in plants is limited so their ecotoxicological impact is poorly documented. To date there are no studies on the phytotoxic effects of functionalized halloysites (functionalized-HNTs). To develop a quantitative risk assessment model for predicting the potential impact of HNT-supported palladium nanoparticles (HNT-PdNPs) on plant life, an investigation was undertaken to explore their effects on seed germination, seedling development, and mitotic division in root tip cells of 2 lots of Raphanus sativus L. with different vigor. The results showed that exposure to 1500 mg/L of HNTs, functionalized-HNTs, and HNT-PdNPs had no significant influence on germination, seedling development, xylem differentiation, or mitotic index in both lots. Cytogenetic analyses revealed that treatments with functionalized-HNT significantly increased the number of aberrations in low-vigor seeds. These results suggest that low-vigor seeds represent a model for a stress test that would be useful to monitor the effects of NPs. Moreover the present study offers scientific evidence for the use of halloysite for environmental purposes, supporting the biological safety of HNT-PdNPs. Environ Toxicol Chem 2016;35:2503-2510. © 2016 SETAC.


Assuntos
Silicatos de Alumínio/toxicidade , Nanopartículas Metálicas/toxicidade , Nanotubos/toxicidade , Paládio/toxicidade , Raphanus/efeitos dos fármacos , Animais , Argila , Germinação/efeitos dos fármacos , Raphanus/crescimento & desenvolvimento , Medição de Risco , Sementes/efeitos dos fármacos
9.
Sci Total Environ ; 551-552: 228-37, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26878635

RESUMO

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.


Assuntos
Silicatos de Alumínio/toxicidade , Mutagênicos/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia , Animais , Biomarcadores/metabolismo
10.
Chemosphere ; 146: 362-70, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26735738

RESUMO

Oil sands process-affected water (OSPW) is a byproduct of the extraction of bitumen in the surface-mining oil sands industry and is currently stored in on-site tailings ponds. OSPW from three oil sands companies were studied to capture some of the variability associated with OSPW characteristics. To investigate the effect and mechanism(s) of effect of OSPW on feeding behaviour, Daphnia magna were exposed to low OSPW concentrations for 24 h and monitored for their feeding rate, olfactory response and swimming activity. The Al and Si content, which are indicators of suspended particulate matter in D. magna exposed to OSPW were investigated using energy-dispersive X-ray (EDX) spectroscopy. In long-term experiments, effects of exposure to OSPW for 21 days on feeding behaviour, growth, and reproduction of D. magna were evaluated. Feeding rates were similar among the three exposure populations, yielding a 24 h IC50 of 5.3% OSPW. Results of behavioural assays suggest that OSPW impairs the chemosensory function and reduces the total activity of D. magna. In EDX spectroscopy, Al and Si were detected in the body of the exposed D. magna, suggesting that D. magna filter clay particles from the OSPW solution. Results of the long-term exposure showed that OSPW significantly inhibits feeding behaviour, suppresses growth, and reduces reproductive output of D. magna. There were no differences in the toxicity of the three samples of OSPW, which was in agreement with the fact that there were no differences in the species of dissolved organic compounds in the OSPW samples.


Assuntos
Daphnia/efeitos dos fármacos , Resíduos Industriais/efeitos adversos , Campos de Petróleo e Gás , Poluentes Químicos da Água/toxicidade , Silicatos de Alumínio/toxicidade , Animais , Comportamento Animal/efeitos dos fármacos , Argila , Daphnia/fisiologia , Ingestão de Alimentos/efeitos dos fármacos , Hidrocarbonetos , Reprodução/efeitos dos fármacos , Natação
11.
Scand J Work Environ Health ; 42(1): 80-5, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26659652

RESUMO

OBJECTIVES: DAS was an artificial clay which, once molded, hardened at room temperature. It was largely used as a toy between 1963 and 1975 in Italy, Netherlands, Germany, UK and Norway. This case report describes and reports the presence of asbestos in DAS. METHODS: We investigated the presence of asbestos in DAS using light and electron microscopy on samples of the original material. We searched administrative documents at the State Archive of Turin and conducted interviews with past employees on annual production, suppliers, and purchasers. RESULTS: The analytical tests confirmed the presence of asbestos fibers in DAS: about 30% of its composition. The documents found at the State Archive confirmed the annual purchase of hundreds tons of raw asbestos from the Amiantifera di Balangero, the Italian asbestos mine. DAS was found to be used also within craftsmanship. CONCLUSIONS: Asbestos fibers in DAS may have caused exposure to production workers and a variety of users, including artists, teachers, and children. Over 13 years, about 55 million packs of DAS were produced and sold. The number of users is difficult to estimate but may have been in the order of millions. In Italy, a specific question on the use of DAS has been included in a routinely used mesothelioma questionnaire. As DAS was exported to other countries, our findings suggest that mesothelioma patients should be asked about their past use of DAS, in particular individuals not reporting a clear past asbestos exposure. Additionally, this discovery shows the incompleteness of records on asbestos uses and suggests to test items, including toys, imported from countries where asbestos is not forbidden.


Assuntos
Silicatos de Alumínio/toxicidade , Asbestos/toxicidade , Jogos e Brinquedos/lesões , Silicatos de Alumínio/história , Arte/história , Asbestos/história , Argila , Qualidade de Produtos para o Consumidor , Europa (Continente) , Feminino , História do Século XX , História do Século XXI , Humanos , Masculino , Mesotelioma/epidemiologia , Mesotelioma/etiologia , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Professores Escolares
12.
Int J Toxicol ; 34(3 Suppl): 43S-52S, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26684795

RESUMO

The Cosmetic Ingredient Review Expert Panel (the Panel) reviewed the safety of synthetic fluorphlogopite as used in cosmetics. Synthetic fluorphlogopite functions as a bulking agent and a viscosity-increasing agent. The Panel reviewed available animal and human data related to this ingredient along with a previous safety assessment of other magnesium silicates. The Panel concluded that synthetic fluorphlogopite was safe as cosmetic ingredients in the practices of use and concentration as given in this safety assessment.


Assuntos
Silicatos de Alumínio/toxicidade , Qualidade de Produtos para o Consumidor , Cosméticos/toxicidade , Silicatos de Alumínio/química , Silicatos de Alumínio/farmacocinética , Animais , Cosméticos/química , Cosméticos/farmacocinética , Dano ao DNA/efeitos dos fármacos , Bases de Dados Factuais , Relação Dose-Resposta a Droga , Humanos , Silicatos de Magnésio/química , Silicatos de Magnésio/toxicidade , Medição de Risco , Pele/efeitos dos fármacos , Pele/metabolismo , Testes de Toxicidade
13.
J Dent ; 43(11): 1316-22, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26334950

RESUMO

OBJECTIVE: To investigate the effects of Halloysite® aluminosilicate clay nanotubes (HNTs) addition on selected physical, mechanical, and biological properties of experimental adhesive resins. METHODS: Experimental dentin adhesive resins were prepared by mixing Bis-GMA, TEGDMA, HEMA (50/25/25wt.%), and photo-initiators. As-received HNTs were then incorporated into the resin mixture at distinct concentrations: 0 (HNT-free, control), 1, 2.5, 5, 7.5, 10, and 20wt.%. The degree of conversion (DC), radiopacity (RP), Knoop hardness (KHN), flexural strength (FS), and cytotoxicity analyses were carried out for each adhesive formulation. The adhesive resin of Adper Scotchbond Multi-Purpose (SBMP) was used as the commercially available reference for both the RP and cytotoxicity tests. Data were statistically analyzed using One-Way ANOVA and Tukey's test (p≤0.05). RESULTS: All adhesives exhibited similar DC (p=0.1931). The RP of adhesives was improved with the addition of up to 5wt.% of HNTs (p<0.001). Adhesives containing 5-10wt.% of HNTs led to greater KHN when compared to the control (p<0.001). The FS was reduced only when 20wt.% of HNTs was added (p≤0.001). None of the prepared adhesives was cytotoxic. CONCLUSION: The incorporation of up to 10wt.% of HNTs into the adhesive resins did not jeopardize the tested physical and biological properties. CLINICAL SIGNIFICANCE: When using HNTs as carriers of drugs/bioactive compounds, the amount of the former added into adhesive resin materials should not exceed 10wt.%; otherwise, a significant reduction in physicomechanical properties may be expected.


Assuntos
Silicatos de Alumínio/química , Cimentos Dentários/química , Resinas Sintéticas/química , Silicatos de Alumínio/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Argila , Cimentos Dentários/toxicidade , Portadores de Fármacos , Dureza , Humanos , Teste de Materiais , Nanotubos , Resinas Sintéticas/toxicidade
14.
J Hazard Mater ; 298: 178-87, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26051993

RESUMO

We assessed the ability of an artificial clay (Ca-aminoclay) to suppress harmful algal bloom species (HABs) such as Cochlodinium polykrikoides and Chattonella marina and investigated the ecological responses in the closed and open microcosm systems. The Ca-aminoclay induced rapidly and selectively cell lysis in the HABs. However, applying Ca-aminoclay could cause adverse impacts in terms of biological and environmental changes. The bacterioplankton abundance increased and then, the abundances of heterotrophic nanoflagellates and ciliates increased rapidly. Extremely poor environmental conditions such as increase in nutrients and development of anoxic conditions were sustained continuously in a closed system, while the environmental conditions in open systems deteriorated before recovering to the initial conditions. We evaluated the potential for the occurrence of a bloom of another phytoplankton after HABs had been controlled using the Ca-aminoclay. The Ca-aminoclay controlled blooms of Chattonella marina in mixed cell cultures containing a Tetraselmis chui. However, T. chui increased over time and then bloomed. Therefore, caution should be taken when considering the direct application of Ca-aminoclay in natural environments even though it offers the rapid removal of HABs.


Assuntos
Silicatos de Alumínio/toxicidade , Ecossistema , Proliferação Nociva de Algas/efeitos dos fármacos , Praguicidas/toxicidade , Cálcio/química , Argila , Plâncton/química , Microbiologia da Água , Poluição da Água/efeitos adversos
15.
Toxicol In Vitro ; 29(6): 1222-30, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25820134

RESUMO

Modern food packaging has made great advances as result of global trends and consumer preferences, which are oriented to obtain improved food quality and safety. In this regard, clay minerals, and mainly Montmorillonite (Mt) are attracting considerable interest in food packaging because of the improvements developed in mechanical and barrier properties. Hence, the present work aim to assess the toxicity of four Montmorillonite-based clay minerals, an unmodified clay, Cloisite®Na+ (CNa+), and three modified Mt clays: Cloisite®30B (C30B), a commercial clay, and Clay1 and Clay2, two novel modified organoclays developed by the Packaging, Transport, & Logistics Research Institute (ITENE). First, the cytotoxic effects were studied in the Human Umbilical Vein Endothelial Cells (HUVEC). In addition, the potential mutagenicity of the clays was evaluated by the Ames test. Clay1 did not induce any cytotoxic effects in HUVEC, although it exhibited potential mutagenicity in TA98 Salmonella typhimurium strain. In contrast, Clay2 produced cytotoxicity in endothelial cells but no mutagenicity was recorded. However, CNa+ was not cytotoxic neither mutagenic. And finally, C30B showed positive results in both assays. Therefore, results showed that clay minerals have a different toxicity profile and a case by case toxicity evaluation is required.


Assuntos
Bentonita/toxicidade , Embalagem de Alimentos , Mutagênicos/toxicidade , Silicatos de Alumínio/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Argila , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Testes de Mutagenicidade
16.
J Colloid Interface Sci ; 448: 501-7, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-25778738

RESUMO

This paper reports on the preparation, characterization, and cytotoxicity of a hybrid nanocomposite material made of Sr(II)-loaded Halloysite nanotubes included within a biopolymer (3-polyhydroxybutyrate-co-3-hydroxyvalerate) matrix. The Sr(II)-loaded inorganic scaffold is intended to provide mechanical resistance, multi-scale porosity, and to favor the in-situ regeneration of bone tissue thanks to its biocompatibility and bioactivity. The interaction of the hybrid system with the physiological environment is mediated by the biopolymer coating, which acts as a binder, as well as a diffusional barrier to the Sr(II) release. The degradation of the polymer progressively leads to the exposure of the Sr(II)-loaded Halloysite scaffold, tuning its interaction with osteogenic cells. The in vitro biocompatibility of the composite was demonstrated by cytotoxicity tests on L929 fibroblast cells. The results indicate that this composite material could be of interest for multiple strategies in the field of bone tissue engineering.


Assuntos
Silicatos de Alumínio/química , Materiais Biocompatíveis/química , Preparações de Ação Retardada/química , Nanotubos/química , Poliésteres/química , Estrôncio/administração & dosagem , Silicatos de Alumínio/toxicidade , Animais , Materiais Biocompatíveis/toxicidade , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Argila , Preparações de Ação Retardada/toxicidade , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Camundongos , Nanocompostos/química , Nanocompostos/toxicidade , Nanocompostos/ultraestrutura , Nanotubos/toxicidade , Nanotubos/ultraestrutura , Poliésteres/toxicidade , Estrôncio/farmacologia
17.
Environ Res ; 138: 233-54, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25732897

RESUMO

Clays and clay minerals are widely used in many facets of our society. This review addresses the main clays of each phyllosilicate groups, namely, kaolinite, montmorillonite (Mt) and sepiolite, placing special emphasis on Mt and kaolinite, which are the clays that are more frequently used in food packaging, one of the applications that are currently exhibiting higher development. The improvements in the composite materials obtained from clays and polymeric matrices are remarkable and well known, but the potential toxicological effects of unmodified or modified clay minerals and derived nanocomposites are currently being investigated with increased interest. In this sense, this work focused on a review of the published reports related to the analysis of the toxicological profile of commercial and novel modified clays and derived nanocomposites. An exhaustive review of the main in vitro and in vivo toxicological studies, antimicrobial activity assessments, and the human and environmental impacts of clays and derived nanocomposites was performed. From the analysis of the scientific literature different conclusions can be derived. Thus, in vitro studies suggest that clays in general induce cytotoxicity (with dependence on the clay, concentration, experimental system, etc.) with different underlying mechanisms such as necrosis/apoptosis, oxidative stress or genotoxicity. However, most of in vivo experiments performed in rodents showed no clear evidences of systemic toxicity even at doses of 5000mg/kg. Regarding to humans, pulmonary exposure is the most frequent, and although clays are usually mixed with other minerals, they have been reported to induce pneumoconiosis per se. Oral exposure is also common both intentionally and unintentionally. Although they do not show a high toxicity through this pathway, toxic effects could be induced due to the increased or reduced exposure to mineral elements. Finally, there are few studies about the effects of clay minerals on wildlife, with laboratory trials showing contradictory outcomes. Clay minerals have different applications in the environment, thus with a strict control of the concentrations used, they can provide beneficial uses. Despite the extensive number of reports available, there is also a need of systematic in vitro-in vivo extrapolation studies, with still scarce information on toxicity biomarkers such as inmunomodulatory effects or alteration of the genetic expression. In conclusion, a case by case toxicological evaluation is required taking into account that different clays have their own toxicological profiles, their modification can change this profile, and the potential increase of the human/environmental exposure to clay minerals due to their novel applications.


Assuntos
Silicatos de Alumínio/toxicidade , Minerais/toxicidade , Nanocompostos/toxicidade , Animais , Bentonita/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Argila , Embalagem de Alimentos , Humanos , Caulim/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Roedores
18.
Braz. j. med. biol. res ; 48(3): 267-272, 03/2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-741252

RESUMO

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.


Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Silicatos de Alumínio/toxicidade , Doenças Profissionais/induzido quimicamente , Exposição Ocupacional/efeitos adversos , Fibrose Pulmonar/induzido quimicamente , Biópsia , Evolução Fatal , Testes de Função Respiratória
20.
Part Fibre Toxicol ; 11: 67, 2014 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-25497478

RESUMO

BACKGROUND: Ge-imogolites are short aluminogermanate tubular nanomaterials with attractive prospected industrial applications. In view of their nano-scale dimensions and high aspect ratio, they should be examined for their potential to cause respiratory toxicity. Here, we evaluated the respiratory biopersistence and lung toxicity of 2 samples of nanometer-long Ge-imogolites. METHODS: Rats were intra-tracheally instilled with single wall (SW, 70 nm length) or double wall (DW, 62 nm length) Ge-imogolites (0.02-2 mg/rat), as well as with crocidolite and the hard metal particles WC-Co, as positive controls. The biopersistence of Ge-imogolites and their localization in the lung were assessed by ICP-MS, X-ray fluorescence, absorption spectroscopy and computed micro-tomography. Acute inflammation and genotoxicity (micronuclei in isolated type II pneumocytes) was assessed 3 d post-exposure; chronic inflammation and fibrosis after 2 m. RESULTS: Cytotoxic and inflammatory responses were shown in bronchoalveolar lavage 3 d after instillation with Ge-imogolites. Sixty days after exposure, a persistent dose-dependent inflammation was still observed. Total lung collagen, reflected by hydroxyproline lung content, was increased after SW and DW Ge-imogolites. Histology revealed lung fibre reorganization and accumulation in granulomas with epithelioid cells and foamy macrophages and thickening of the alveolar walls. Overall, the inflammatory and fibrotic responses induced by SW and DW Ge-imogolites were more severe (on a mass dose basis) than those induced by crocidolite. A persistent fraction of Ge-imogolites (15% of initial dose) was mostly detected as intact structures in rat lungs 2 m after instillation and was localized in fibrotic alveolar areas. In vivo induction of micronuclei was significantly increased 3 d after SW and DW Ge-imogolite instillation at non-inflammatory doses, indicating the contribution of primary genotoxicity. CONCLUSIONS: We showed that nm-long Ge-imogolites persist in the lung and promote genotoxicity, sustained inflammation and fibrosis, indicating that short high aspect ratio nanomaterials should not be considered as innocuous materials. Our data also suggest that Ge-imogolite structure and external surface determine their toxic activity.


Assuntos
Silicatos de Alumínio/toxicidade , Germânio/toxicidade , Exposição por Inalação/efeitos adversos , Pulmão/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Pneumonia/induzido quimicamente , Fibrose Pulmonar/etiologia , Poluentes Atmosféricos/química , Poluentes Atmosféricos/toxicidade , Silicatos de Alumínio/administração & dosagem , Silicatos de Alumínio/química , Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/imunologia , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/patologia , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Feminino , Germânio/administração & dosagem , Germânio/química , Pulmão/imunologia , Pulmão/patologia , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Nanotubos/química , Nanotubos/toxicidade , Tamanho da Partícula , Pneumonia/imunologia , Pneumonia/patologia , Ratos Wistar , Mucosa Respiratória/efeitos dos fármacos , Mucosa Respiratória/imunologia , Mucosa Respiratória/patologia , Absorção pelo Trato Respiratório , Distribuição Tecidual , Testes de Toxicidade Aguda , Toxicocinética
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