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1.
Burns ; 49(7): 1541-1556, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-36914442

RESUMO

PURPOSE: To clarify and elaborate on the choices that were made in the development of the Patient Scale of the Patient and Observer Scar Assessment Scale 3.0 (POSAS 3.0), based upon the rich information obtained from patients during focus groups and pilot tests. METHODS: The discussions described in this paper are a reflection of the focus group study and pilot tests that were conducted in order to develop the Patient Scale of the POSAS3.0. The focus groups took place in the Netherlands and Australia and included 45 participants. Pilot tests were performed with 15 participants in Australia, the Netherlands, and the United Kingdom. RESULTS: We discussed the selection, wording and merging of 17 included items. Additionally, the reason for exclusion of 23 characteristics are given. CONCLUSION: Based upon the unique and rich material of patient input obtained, two versions of the Patient Scale of the POSAS3.0 were developed: the Generic version, and the Linear scar version. The discussions and decisions taken during the development are informative for a good understanding of the POSAS 3.0 and are indispensable as a background for future translations and cross-cultural adaptations.


Assuntos
Queimaduras , Cicatriz , Humanos , Cicatriz/patologia , Queimaduras/complicações , Países Baixos , Pacientes , Austrália
2.
Qual Life Res ; 32(2): 583-592, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36355319

RESUMO

PURPOSE: The Patient and Observer Scar Assessment Scale (POSAS) is widely used for measurements of scar quality. This encompasses visual, tactile and sensory characteristics of the scar. The Patient Scale of previous POSAS versions was lacking input from patients. Therefore, the aim of this study was to develop the POSAS3.0, Patient Scale with involvement of adults patients with all scar types, complying with the highest clinimetric standards. METHODS: From February 2018 to April 2019, a series of six focus group interviews were performed in the Netherlands and Australia to identify scar quality characteristics that adults with scars consider to be important. All focus groups were transcribed, anonymized and analysed using a thematic analysis. Relevant characteristics were formulated into items, resulting in a Dutch and English version of the Patient Scale. These drafts were pilot tested in Australia, the Netherlands and the United Kingdom, and refined accordingly. RESULTS: A total of 21 relevant scar quality characteristics were identified during the focus groups. Two distinct versions of the POSAS3.0, Patient Scale were developed. The Generic version contains 16 items and can be used for all scar types, except linear scars. The Linear Scar version of the Patient Scale contains the same 16 items, with an extra item referring to the widening of scar margins. All included items are rated on a verbal rating scale with five response options. CONCLUSION: Two versions of the POSAS3.0 Patient Scale were developed. Further field tests are being performed to establish the measurement properties and scoring algorithm of the scales.


Assuntos
Cicatriz , Qualidade de Vida , Adulto , Humanos , Qualidade de Vida/psicologia , Padrões de Referência , Pesquisa Qualitativa , Grupos Focais
3.
Nanoscale Adv ; 3(21): 6213-6222, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36133951

RESUMO

In nanomedicine, treatments based on physical mechanisms are more and more investigated and are promising alternatives for challenging tumor therapy. One of these approaches, called magneto-mechanical treatment, consists in triggering cell death via the vibration of anisotropic magnetic particles, under a low frequency magnetic field. In this work, we introduce a new type of easily accessible magnetic microparticles (MMPs) and study the influence of their surface functionalization on their ability to induce such an effect, and its mechanism. We prepared anisotropic magnetite microparticles by liquid-phase ball milling of a magnetite powder. These particles are completely different from the often-used SPIONs: they are micron-size, ferromagnetic, with a closed-flux magnetic structure reminiscent of that of vortex particles. The magnetic particles were covered with a silica shell, and grafted with PEGylated ligands with various physicochemical properties. We investigated both bare and coated particles' in vitro cytotoxicity, and compared their efficiency to induce U87-MG human glioblastoma cell apoptosis under a low frequency rotating magnetic field (RMF). Our results indicated that (1) the magneto-mechanical treatment with bare MMPs induces a rapid decrease in cell viability whereas the effect is slower with PEGylated particles; (2) the number of apoptotic cells after magneto-mechanical treatment is higher with PEGylated particles; (3) a lower frequency of RMF (down to 2 Hz) favors the apoptosis. These results highlight a difference in the cell death mechanism according to the properties of particles used - the rapid cell death observed with the bare MMPs indicates a death pathway via necrosis, while PEGylated particles seem to favor apoptosis.

5.
Sci Total Environ ; 630: 609-617, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29494970

RESUMO

Nanoparticles (NPs) and in particular TiO2-NPs are increasingly included in commercial goods leading to their accumulation in sewage sludge which is spread on agricultural soils as fertilizers in many countries. Crop plants are thus a very likely point of entry for NPs in the food chain up to humans. So far, soil influence on NP fate has been under-investigated. In this article, we studied the partitioning of TiO2-NPs between soil and soil leachate, their uptake and biotransformation in wheat seedlings and their impact on plant development after exposure on 4 different types of soil with different characteristics: soil texture (from sandy to clayey), soil pH, cationic exchange capacity, organic matter content. Results suggest that a NP contamination occurring on agricultural soils will mainly lead to NP accumulation in soil (increase of Ti concentration up to 302% in sand) but to low to negligible transfer to soil leachate and plant shoot. In our experimental conditions, no sign of acute phytotoxicity has been detected (growth, biomass, chlorophyll content). Clay content above 6% together with organic matter content above 1.5% lead to translocation factor from soil to plant leaves below 2.5% (i.e. below 13mgTi·kg-1 dry leaves). Taken together, our results suggest low risk of crop contamination in an agro-ecosystem.


Assuntos
Agricultura , Ecossistema , Monitoramento Ambiental , Nanopartículas/análise , Poluentes do Solo/análise , Titânio/análise , Solo/química
6.
Burns ; 43(7): 1516-1523, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28536040

RESUMO

BACKGROUND: Objective measurement tools may be of great value to provide early and reliable burn wound assessment. Thermal imaging is an easy, accessible and objective technique, which measures skin temperature as an indicator of tissue perfusion. These thermal images might be helpful in the assessment of burn wounds. However, before implementation of a novel measurement tool into clinical practice is considered, it is appropriate to test its clinimetric properties (i.e. reliability and validity). The objective of this study was to assess the reliability and validity of the recently introduced FLIR ONE thermal imager. MATERIAL AND METHODS: Two observers obtained thermal images of burn wounds in adult patients at day 1-3, 4-7 and 8-10 after burn. Subsequently, temperature differences between the burn wound and healthy skin (ΔT) were calculated on an iPad mini containing the FLIR Tools app. To assess reliability, ΔT values of both observers were compared by calculating the intraclass correlation coefficient (ICC) and measurement error parameters. To assess validity, the ΔT values of the first observer were compared to the registered healing time of the burn wounds, which was specified into three categories: (I) ≤14 days, (II) 15-21 days and (III) >21 days. The ability of the FLIR ONE to discriminate between healing ≤21 days and >21 days was evaluated by means of a receiver operating characteristic curve and an optimal ΔT cut-off value. RESULTS: Reliability: ICCs were 0.99 for each time point, indicating excellent reliability up to 10 days after burn. The standard error of measurement varied between 0.17-0.22°C. VALIDITY: the area under the curve was calculated at 0.69 (95% CI 0.54-0.84). A cut-off value of -1.15°C shows a moderate discrimination between burn wound healing ≤21 days and >21 days (46% sensitivity; 82% specificity). CONCLUSION: Our results show that the FLIR ONE thermal imager is highly reliable, but the moderate validity calls for additional research. However, the FLIR ONE is pre-eminently feasible, allowing easy and fast measurements in clinical burn practice.


Assuntos
Queimaduras/diagnóstico por imagem , Pele/diagnóstico por imagem , Termografia/instrumentação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Queimaduras/diagnóstico , Computadores de Mão , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Reprodutibilidade dos Testes , Temperatura , Fatores de Tempo , Cicatrização , Adulto Jovem
7.
Mutagenesis ; 32(1): 161-172, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27803034

RESUMO

For some decades production of titanium dioxide nanoparticle (TiO2-NP) has been increasing at a considerable rate; concerns as to the toxicity of these particles upon inhalation have been raised. Indeed, TiO2-NPs have been shown to induce significant genotoxicity and to adversely affect both major DNA repair mechanisms: base excision repair (BER) and nucleotide excision repair (NER). The aims of the present study were to (i) compare the genotoxicity of TiO2-NPs and their impact on DNA repair processes on A549 alveolar carcinoma and BEAS-2B normal bronchial lung cell lines and (ii) delve deeper into the mechanisms leading to these effects. To achieve these goals, TiO2-NPs effects on cytotoxicity, genotoxicity, DNA repair activity and DNA repair gene expression were investigated in both cell lines upon exposure to 1-100 µg/mL of anatase/rutile, 21 nm TiO2-NPs. Our results show that TiO2-NPs induce comparable cytotoxic and genotoxic responses in BEAS-2B and A549 cells. Functional response to DNA damage is observed in both cell lines and consists of an overall downregulation in DNA repair processes. When evaluating the relative importance of the two DNA repair pathways, we observed a lower impact on BER compared with NER activities, suggesting that repair of oxidatively generated DNA damage is still triggered in these cells. This response becomes measureable at 4 h of exposure in BEAS-2B but only after 48 h of exposure in A549 cells. The delayed response in A549 cells is due to an initial overall and intense downregulation of the genes encoding DNA repair proteins. This overall downregulation correlates with increased methylation of DNA repair gene promoters and downregulation of NRF2 and BRCA1, which may thus be considered as upstream regulators. These results strengthen the evidence that TiO2-NP induces indirect genotoxicity in lung cells, via modulation of DNA repair processes, and shed some light on the mechanisms behind this effect.


Assuntos
Metilação de DNA , Enzimas Reparadoras do DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Células A549 , Linhagem Celular , DNA/efeitos dos fármacos , DNA/metabolismo , Dano ao DNA , Reparo do DNA/genética , Enzimas Reparadoras do DNA/genética , Regulação para Baixo , Humanos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Nanopartículas Metálicas/química , Testes de Mutagenicidade , Estresse Oxidativo , Regiões Promotoras Genéticas
8.
Nanoscale ; 8(38): 17012-17021, 2016 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-27722394

RESUMO

Silver nanoparticles (AgNPs) can enter eukaryotic cells and exert toxic effects, most probably as a consequence of the release of Ag+ ions. Due to the elusive nature of Ag+ ionic species, quantitative information concerning AgNP intracellular dissolution is missing. By using a synchrotron nanoprobe, silver is visualized and quantified in hepatocytes (HepG2) exposed to AgNPs; the synergistic use of electron microscopy allows for the discrimination between nanoparticular and ionic forms of silver within a single cell. AgNPs are located in endocytosis vesicles, while the visualized Ag+ ions diffuse in the cell. The averaged NP dissolution rates, measured by X-ray absorption spectroscopy, highlight the faster dissolution of citrate-coated AgNPs with respect to the less toxic PVP-coated AgNPs; these results are confirmed at the single-cell level. The released Ag+ ions recombine with thiol-bearing biomolecules: the Ag-S distances measured in cellulo, and the quantitative evaluation of gene expression, provide independent evidence of the involvement of glutathione and metallothioneins in Ag+ binding. The combined use of cutting-edge imaging techniques, atomic spectroscopy and molecular biology brings insight into the fate of AgNPs in hepatocytes, and more generally into the physicochemical transformations of metallic nanoparticles in biological environments and the resulting disruption of metal homeostasis.


Assuntos
Hepatócitos/metabolismo , Nanopartículas Metálicas , Prata/análise , Citratos , Células Hep G2 , Humanos , Íons
9.
Nanoscale ; 7(16): 7323-30, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25824974

RESUMO

Silver nanoparticle (AgNP) toxicity is related to their dissolution in biological environments and to the binding of the released Ag(+) ions in cellulo; the chemical environment of recombined Ag(+) ions is responsible for their toxicological outcome, moreover it is indicative of the cellular response to AgNP exposure, and can therefore shed light on the mechanisms governing AgNP toxicity. This study probes the chemistry of Ag species in primary murine macrophages exposed to AgNPs by making use of X-ray Absorption Fine Structure spectroscopy under cryogenic conditions: the linear combination analysis of the near-edge region of the spectra provides the fraction of Ag(+) ions released from the AgNPs under a given exposure condition and highlights their complexation with thiolate groups; the ab initio modelling of the extended spectra allows measuring the Ag-S bond length in cellulo. Dissolution rates depend on the exposure scenario, chronicity leading to higher Ag(+) release than acute exposure; Ag-S bond lengths are 2.41 ± 0.03 Å and 2.38 ± 0.01 Å in acute and chronic exposure respectively, compatible with digonal AgS2 coordination. Glutathione is identified as the most likely putative ligand for Ag(+). The proposed method offers a scope for the investigation of metallic nanoparticle dissolution and recombination in cellular models.


Assuntos
Nanopartículas Metálicas/química , Compostos de Prata/química , Prata/química , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Glutationa/química , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Nanopartículas Metálicas/toxicidade , Camundongos , Microscopia Eletrônica de Transmissão , Espectroscopia por Absorção de Raios X
10.
Nanoscale ; 7(16): 7352-60, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25825056

RESUMO

TiO2 microparticles are widely used in food products, where they are added as a white food colouring agent. This food additive contains a significant amount of nanoscale particles; still the impact of TiO2 nanoparticles (TiO2-NPs) on gut cells is poorly documented. Our study aimed at evaluating the impact of rutile and anatase TiO2-NPs on the main functions of enterocytes, i.e. nutrient absorption driven by solute-liquid carriers (SLC transporters) and protection against other xenobiotics driven by efflux pumps from the ATP-binding cassette (ABC) family. We show that acute exposure of Caco-2 cells to both anatase (12 nm) and rutile (20 nm) TiO2-NPs induce early upregulation of a battery of efflux pumps and nutrient transporters. In addition they cause overproduction of reactive oxygen species and misbalance redox repair systems, without inducing cell mortality or DNA damage. Taken together, these data suggest that TiO2-NPs may increase the functionality of gut epithelial cells, particularly their property to form a protective barrier against exogenous toxicants and to absorb nutrients.


Assuntos
Nanopartículas Metálicas/química , Titânio/química , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Transportador de Glucose Tipo 1/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Humanos , Intestinos/citologia , Nanopartículas Metálicas/toxicidade , Espécies Reativas de Oxigênio/metabolismo
11.
Mucosal Immunol ; 8(1): 127-40, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24985081

RESUMO

Massive loss of lamina propria CD4(+) T cells, changes in the lymphatic architecture, and altered intestinal epithelial barrier leading to microbial translocation are the common features of HIV-1 infection and are not fully restored under combined antiretroviral therapy (cART). To better understand determinants of gut mucosal restoration, we have performed phenotypic and gene expression analyses of the gut from HIV-infected patients, naive or treated with cART initiated either at the early phase of the primary infection or later during the chronic phase. We found a depletion of T helper type 22 (Th22) and interleukin-17-producing cells in naive patients. These populations, except Th22 cells, were not restored under cART. Regulatory T cells/Th17 ratio was significantly increased in HIV-infected patients and was inversely correlated to the restoration of CD4(+) T cells but not to gut HIV DNA levels. Gene profile analysis of gut mucosal distinguished two groups of patients, which fitted with the timing of cART initiation. In their majority early, but not later treated patients, exhibited conserved intestinal lymphoid structure, epithelial barrier integrity and dendritic cell maturation pathways. Our data demonstrate that early initiation of cART helps to preserve and/or restore lymphoid gut mucosal homeostasis and provide a rationale for initiating cART during the acute phase of HIV infection.


Assuntos
Antirretrovirais/uso terapêutico , Células Dendríticas/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Linfócitos T Reguladores/efeitos dos fármacos , Células Th17/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , DNA Viral/sangue , Células Dendríticas/imunologia , Células Dendríticas/virologia , Progressão da Doença , Quimioterapia Combinada , Feminino , Perfilação da Expressão Gênica , Infecções por HIV/imunologia , HIV-1/fisiologia , Humanos , Imunidade nas Mucosas/efeitos dos fármacos , Interleucinas/metabolismo , Intestinos/imunologia , Intestinos/virologia , Masculino , Pessoa de Meia-Idade , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/virologia , Células Th17/imunologia , Células Th17/virologia , Resultado do Tratamento , Interleucina 22
12.
Child Care Health Dev ; 40(6): 825-32, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24028505

RESUMO

CONTEXT: In 2003, Quebec's Ministry of Health and Social Services (MSSS) and the Ministry of Education, Recreation and Sports (MELS) concluded the Agreement for the complementarity of services between the health and social services network and the education network. The objectives of the current investigation were to evaluate the implementation of this Agreement and its impact upon renewal of practices and services, and to investigate the consequences for children with special needs and their families. The specific focus of this article is to describe parents' perspectives regarding the impact of this Agreement upon them and their children. METHODS: Interviews were conducted with 56 parents of children with disabilities, social maladjustment or learning difficulties across the province of Quebec. Data were analysed using content analysis. RESULTS: Most parents were not directly aware of any contact between school staff and health or social professionals, although discussions might have been held without their knowledge. The intervention plans seemed to be the main vehicle through which some parents perceived collaboration to be occurring. For parents, the impact upon actual practices or collaborative work is either minimal or non-existent. CONCLUSION: School inclusion of children with special needs is a challenge for all societies. The Agreement illustrates the Quebec government's intent to promote an alliance between two complex networks and has the potential to greatly benefit children and their families. However, more concrete action is required in order to realize specific changes regarding work cohesion and service organization for these groups.


Assuntos
Serviços de Saúde da Criança , Crianças com Deficiência/psicologia , Deficiências da Aprendizagem/psicologia , Pais , Isolamento Social/psicologia , Apoio Social , Acesso à Informação , Adolescente , Adulto , Atitude do Pessoal de Saúde , Criança , Serviços de Saúde da Criança/organização & administração , Pré-Escolar , Comportamento Cooperativo , Atenção à Saúde , Crianças com Deficiência/estatística & dados numéricos , Educação Inclusiva , Feminino , Acessibilidade aos Serviços de Saúde/organização & administração , Humanos , Deficiências da Aprendizagem/epidemiologia , Masculino , Pais/educação , Pais/psicologia , Equipe de Assistência ao Paciente/organização & administração , Satisfação do Paciente , Relações Profissional-Família , Quebeque/epidemiologia , Instituições Acadêmicas/organização & administração , Serviço Social/organização & administração , Inquéritos e Questionários
13.
J Biomed Nanotechnol ; 7(1): 22-3, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21485783

RESUMO

Titania nanoparticles are produced by tons, and included in commercial products, raising concerns about their potential impact on human health. This study relates their cytotoxic and genotoxic impact on a cell line representative of human lung, namely A549 alveolar epithelial cells.


Assuntos
Neoplasias Pulmonares/fisiopatologia , Nanopartículas Metálicas/toxicidade , Testes de Mutagenicidade/métodos , Testes de Toxicidade Aguda/métodos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citotoxinas/toxicidade , Relação Dose-Resposta a Droga , Humanos , Mutagênicos/toxicidade , Titânio/toxicidade
14.
Br Poult Sci ; 52(6): 792-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22221246

RESUMO

1.The objectives were to quantify the presence of neurogenic inflammation in 4 regions of the upper digestive tract of anaesthetised ducks (post-pharynx, pseudo-crop, transition between the pseudo-crop and the proventriculus, and proventriculus) after application of HCl stimulation of up to 4 M in the pseudo-crop. 2.The second objective was to quantify the presence of neurogenic inflammation in the same digestive tract regions as mentioned above during 4 feeding periods of foie gras production (rearing, preparation to force-feeding, and second and last meals of the force-feeding period). 3. Extravasation increased above a HCl stimulation threshold of 2 M. Furthermore, more extravasation was observed in the proventriculus compared to the other regions (P < 0·001). 4.Highest extravasation responses were observed in the proventriculus and the pseudo-crop at the end of the preparation period, and in the proventriculus after the second forced meal, compared with the rearing period (P < 0·01), with a return to rearing level at the end of force-feeding. 5.Such a kinetic could be indicative of a relative mildness of the irritant components associated with this feeding practice.


Assuntos
Patos/imunologia , Nutrição Enteral/efeitos adversos , Ácido Clorídrico/farmacologia , Inflamação Neurogênica/veterinária , Proventrículo/imunologia , Bem-Estar do Animal , Animais , Masculino , Distribuição Aleatória
15.
Toxicol Lett ; 198(3): 324-30, 2010 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-20655996

RESUMO

Silicon carbide (SiC) is considered a highly biocompatible material, consequently SiC nanoparticles (NPs) have been proposed for potential applications in diverse areas of technology. Since no toxicological data are available for these NPs, the aim of this study was to draw their global toxicological profile on A549 lung epithelial cells, using a battery of classical in vitro assays. Five SiC-NPs, with varying diameters and Si/C ratios were used, and we show that these SiC-NPs are internalized in cells where they cause a significant, though limited, cytotoxic effect. Cell redox status is deeply disturbed: SiC-NP exposure cause reactive oxygen species production, glutathione depletion and inactivation of some antioxidant enzymes: glutathione reductase, superoxide dismutase, but not catalase. Finally, the alkaline comet assay shows that SiC-NPs are genotoxic. Taken together, these data prove that SiC-NPs biocompatibility should be revisited.


Assuntos
Compostos Inorgânicos de Carbono/toxicidade , Pulmão/efeitos dos fármacos , Nanopartículas/toxicidade , Estresse Oxidativo , Compostos de Silício/toxicidade , Catalase/análise , Catalase/metabolismo , Linhagem Celular Tumoral , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Formazans/química , Glutationa/análise , Glutationa/metabolismo , Glutationa Redutase/análise , Glutationa Redutase/metabolismo , Humanos , Pulmão/citologia , Pulmão/metabolismo , Microscopia Eletrônica de Transmissão , Testes de Mutagenicidade , Nanopartículas/ultraestrutura , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismo , Estatísticas não Paramétricas , Superóxido Dismutase/análise , Superóxido Dismutase/metabolismo , Sais de Tetrazólio/química
16.
Toxicology ; 253(1-3): 137-46, 2008 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-18835419

RESUMO

If released in the environment, nanomaterials might be inhaled by populations and cause damage to the deepest regions of the respiratory tract, i.e., the alveolar compartment. To model this situation, we studied the response of A549 human pneumocytes after exposure to aluminium oxide or titanium oxide nanoparticles, and to multi-walled carbon nanotubes. The influence of size, crystalline structure and chemical composition was investigated. After a detailed identification of nanomaterial physico-chemical characteristics, cells were exposed in vitro and viability and intracellular accumulation were assessed. In our conditions, carbon nanotubes were more toxic than metal oxide nanoparticles. Our results confirmed that both nanotubes and nanoparticles are able to rapidly enter into cells, and distribute in the cytoplasm and intracellular vesicles. Among nanoparticles, we demonstrate significant difference in biological response as a function of size, crystalline phase and chemical composition. Their toxicity was globally lower than nanotubes toxicity. Among nanotubes, the length did not influence cytotoxicity, neither the presence of metal catalyst impurities.


Assuntos
Citoplasma/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Nanotubos de Carbono/toxicidade , Mucosa Respiratória/efeitos dos fármacos , Óxido de Alumínio/toxicidade , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Citoplasma/ultraestrutura , Células Epiteliais/química , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/ultraestrutura , Humanos , Pulmão/química , Pulmão/ultraestrutura , Nanopartículas Metálicas/análise , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão , Nanotubos de Carbono/análise , Nanotubos de Carbono/química , Mucosa Respiratória/química , Mucosa Respiratória/citologia , Mucosa Respiratória/ultraestrutura , Titânio/toxicidade
17.
Toxicology ; 252(1-3): 26-32, 2008 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-18708117

RESUMO

Uranium (U) and lead (Pb) are accumulated and fixed for long periods in bone, impairing remodeling processes. Their toxicity to osteoblasts, the cells responsible for bone formation, is poorly documented. It has been previously shown that cytotoxicity and phenotypic effects of both metals on osteoblasts are highly influenced by metal speciation. Differences in sensitivity between cell types have been underlined as well. In this paper, cellular accumulation of U and Pb in cultured and primary osteoblastic cells was assessed by trace element analysis. Distribution of different species at the cell scale was investigated by electron microscopy. Internalization of both metals was shown to be correlated to cytotoxicity and population growth recovery after exposure. For each metal, the amount of metal uptake leading to 50% cell death was shown to be speciation-dependent. Scanning and transmission electron microscopy showed the formation of precipitates with phosphate in lysosomes for both metals, whose role in toxicity or cell defence remains to be clarified. Although a clear link was established between cytotoxicity and accumulation, differences in sensitivity observed in terms of speciation could not be fully explained and other studies seem necessary.


Assuntos
Chumbo/química , Chumbo/metabolismo , Osteoblastos/metabolismo , Urânio/química , Urânio/metabolismo , Animais , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/ultraestrutura , Linhagem Celular Tumoral , Simulação por Computador , Relação Dose-Resposta a Droga , Humanos , Espectrometria de Massas , Microscopia Eletrônica de Transmissão e Varredura , Osteoblastos/ultraestrutura , Osteossarcoma/metabolismo , Osteossarcoma/ultraestrutura , Ratos
18.
Toxicology ; 250(1): 62-9, 2008 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-18606205

RESUMO

Bone is one of the main retention organs for uranium (U) and lead (Pb). The clinical effects of U or Pb poisoning are well known: acute and chronic intoxications impair bone formation. However, only few studies dealt with the cellular and molecular mechanisms of their toxicity. The purpose of this study was to investigate acute cytotoxicity of U and Pb and their phenotypic effects on rat and human osteoblasts, the cells responsible for bone formation. The most likely species of the toxicants in contact with cells after blood contamination were selected for cell exposure. Results showed that the cytotoxic effect of U and Pb is highly dependent on their speciation. Thus, Pb was cytotoxic when left free in the exposure medium or when complexed with carbonate, cysteine or citrate, but not when complexed with albumin or phosphate, under an insoluble form. U was cytotoxic whatever its speciation, but differences in sensitivity were observed as a function of speciation. Population growth recovery could be obtained after exposure to low doses of U or Pb, except for some U-carbonate complexes which had irreversible effects whatever the dose. The activation of two markers of bone formation and mineralization, osteocalcin and bone sialoprotein (BSP), was observed after exposure to non-toxic doses or non-toxic species of U or Pb while their inhibition was observed after toxic exposure to both metals. This work provides new elements to better understand the complex mechanisms of U and Pb toxicity to osteoblasts. Our results also illustrate the importance of a strictly controlled speciation of the metals in toxicological studies.


Assuntos
Chumbo/toxicidade , Osteoblastos/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Fenótipo , Compostos de Urânio/toxicidade , Animais , Calcificação Fisiológica/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Chumbo/química , Osteoblastos/metabolismo , Osteocalcina/efeitos dos fármacos , Osteocalcina/metabolismo , Ratos , Sialoglicoproteínas/efeitos dos fármacos , Sialoglicoproteínas/metabolismo , Compostos de Urânio/química
19.
Biochimie ; 88(11): 1605-18, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16996675

RESUMO

In case of accidental release of radionuclides into the environment, actinides represent a severe health risk to human beings following internal contamination (inhalation, ingestion or wound). For a better understanding of the actinide behaviour in man (in term of metabolism, retention, excretion) and in specific biological systems (organs, cells or biochemical pathways), it is of prime importance to have a good knowledge of the relevant actinide solution chemistry and biochemistry, in particular of the thermodynamic constants needed for computing actinide speciation. To a large extent, speciation governs bioavailability and toxicity of elements and has a significant impact on the mechanisms by which toxics accumulate in cell compartments and organs and by which elements are transferred and transported from cell to cell. From another viewpoint, speciation is the prerequisite for the design and success of potential decorporation therapies. The purpose of this review is to present the state of the art of actinide knowledge within biological media. It is also to discuss how actinide speciation can be determined or predicted and to highlight the areas where information is lacking with the aim to encourage new research efforts.


Assuntos
Elementos da Série Actinoide/classificação , Elementos da Série Actinoide/análise , Elementos da Série Actinoide/farmacologia , Elementos da Série Actinoide/toxicidade , Poluição Ambiental , Humanos , Radioisótopos/toxicidade , Termodinâmica
20.
J Viral Hepat ; 13(9): 633-42, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16907851

RESUMO

Alcohol consumption has a major impact on the natural history of chronic hepatitis C virus (HCV) infection, although the underlying mechanisms are still debated. We designed a clinical study to evaluate the impact of alcohol abuse on both viral load and expression of low-density lipoprotein receptor (LDLR) and CD81 expression. Thirty-eight consecutive HCV-infected patients were enrolled. Group 1 (n = 18), < or =10 g alcohol/day, group 2 (n = 8), < or =30 g alcohol/day, group 3 (n = 12), >or =30 g alcohol/day. Receptors expression was measured by flow cytometry analysis in peripheral blood mononuclear cells (PBMC) and by specific real-time retrotranscription polymerase chain reaction (RT-PCR) in the liver. Serum viral load was evaluated by quantification of both HCV genomic RNA and total core antigen. The hepatic viral load was assessed by real-time RT-PCR. Serum HCV-RNA and total core antigen were significantly correlated, and were higher, albeit not significantly, in group 3 than in group 1. Alcohol consumption had no effect on expression of HCV putative receptors in PBMC, except for CD81, which was upregulated on monocytes in group 2. In the liver, viral load and levels of LDLR transcripts were significantly higher in group 3 than in group 1. Remarkably, a significant positive correlation was found between LDLR transcripts and HCV-RNA (r2 = 0.83, P < 10(-3)). Finally, in vitro experiments suggested that the effect of ethanol on LDLR expression was indirectly mediated by both tumour necrosis factor-alpha and interleukin-1beta. In conclusion, this study is the first to support a role for LDLR in the natural infection by HCV in man.


Assuntos
Consumo de Bebidas Alcoólicas , Hepacivirus/fisiologia , Hepatite C Crônica/metabolismo , Hepatite C Crônica/virologia , Fígado/virologia , RNA Viral/análise , Receptores de LDL/genética , Adulto , Antígenos CD/biossíntese , Antígenos CD/genética , Citometria de Fluxo , Perfilação da Expressão Gênica , Hepacivirus/genética , Hepacivirus/isolamento & purificação , Hepatite C Crônica/genética , Humanos , Leucócitos Mononucleares/química , Fígado/metabolismo , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , Receptores de LDL/biossíntese , Receptores Virais/genética , Receptores Virais/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estatística como Assunto , Tetraspanina 28 , Transcrição Gênica , Carga Viral
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