Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
Qual Life Res ; 32(2): 583-592, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36355319

RESUMEN

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.


Asunto(s)
Cicatriz , Calidad de Vida , Adulto , Humanos , Calidad de Vida/psicología , Estándares de Referencia , Investigación Cualitativa , Grupos Focales
2.
Mutagenesis ; 32(1): 161-172, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27803034

RESUMEN

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.


Asunto(s)
Metilación de ADN , Enzimas Reparadoras del ADN/efectos de los fármacos , Reparación del ADN/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Titanio/toxicidad , Células A549 , Línea Celular , ADN/efectos de los fármacos , ADN/metabolismo , Daño del ADN , Reparación del ADN/genética , Enzimas Reparadoras del ADN/genética , Regulación hacia Abajo , Humanos , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Nanopartículas del Metal/química , Pruebas de Mutagenicidad , Estrés Oxidativo , Regiones Promotoras Genéticas
3.
Child Care Health Dev ; 40(6): 825-32, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24028505

RESUMEN

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.


Asunto(s)
Servicios de Salud del Niño , Niños con Discapacidad/psicología , Discapacidades para el Aprendizaje/psicología , Padres , Aislamiento Social/psicología , Apoyo Social , Acceso a la Información , Adolescente , Adulto , Actitud del Personal de Salud , Niño , Servicios de Salud del Niño/organización & administración , Preescolar , Conducta Cooperativa , Atención a la Salud , Niños con Discapacidad/estadística & datos numéricos , Educación Especial , Femenino , Accesibilidad a los Servicios de Salud/organización & administración , Humanos , Discapacidades para el Aprendizaje/epidemiología , Masculino , Padres/educación , Padres/psicología , Grupo de Atención al Paciente/organización & administración , Satisfacción del Paciente , Relaciones Profesional-Familia , Quebec/epidemiología , Instituciones Académicas/organización & administración , Servicio Social/organización & administración , Encuestas y Cuestionarios
4.
Burns ; 49(7): 1541-1556, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-36914442

RESUMEN

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.


Asunto(s)
Quemaduras , Cicatriz , Humanos , Cicatriz/patología , Quemaduras/complicaciones , Países Bajos , Pacientes , Australia
5.
Br Poult Sci ; 52(6): 792-9, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22221246

RESUMEN

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.


Asunto(s)
Patos/inmunología , Nutrición Enteral/efectos adversos , Ácido Clorhídrico/farmacología , Inflamación Neurogénica/veterinaria , Proventrículo/inmunología , Bienestar del Animal , Animales , Masculino , Distribución Aleatoria
6.
Nanoscale Adv ; 3(21): 6213-6222, 2021 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-36133951

RESUMEN

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.

7.
Toxicology ; 252(1-3): 26-32, 2008 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-18708117

RESUMEN

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.


Asunto(s)
Plomo/química , Plomo/metabolismo , Osteoblastos/metabolismo , Uranio/química , Uranio/metabolismo , Animales , Neoplasias Óseas/metabolismo , Neoplasias Óseas/ultraestructura , Línea Celular Tumoral , Simulación por Computador , Relación Dosis-Respuesta a Droga , Humanos , Espectrometría de Masas , Microscopía Electrónica de Transmisión de Rastreo , Osteoblastos/ultraestructura , Osteosarcoma/metabolismo , Osteosarcoma/ultraestructura , Ratas
8.
Toxicology ; 250(1): 62-9, 2008 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-18606205

RESUMEN

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.


Asunto(s)
Plomo/toxicidad , Osteoblastos/efectos de los fármacos , Osteogénesis/efectos de los fármacos , Fenotipo , Compuestos de Uranio/toxicidad , Animales , Calcificación Fisiológica/efectos de los fármacos , Línea Celular , Línea Celular Tumoral , Humanos , Plomo/química , Osteoblastos/metabolismo , Osteocalcina/efectos de los fármacos , Osteocalcina/metabolismo , Ratas , Sialoglicoproteínas/efectos de los fármacos , Sialoglicoproteínas/metabolismo , Compuestos de Uranio/química
9.
Toxicology ; 253(1-3): 137-46, 2008 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-18835419

RESUMEN

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.


Asunto(s)
Citoplasma/efectos de los fármacos , Pulmón/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Nanotubos de Carbono/toxicidad , Mucosa Respiratoria/efectos de los fármacos , Óxido de Aluminio/toxicidad , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Citoplasma/ultraestructura , Células Epiteliales/química , Células Epiteliales/efectos de los fármacos , Células Epiteliales/ultraestructura , Humanos , Pulmón/química , Pulmón/ultraestructura , Nanopartículas del Metal/análisis , Nanopartículas del Metal/química , Microscopía Electrónica de Transmisión , Nanotubos de Carbono/análisis , Nanotubos de Carbono/química , Mucosa Respiratoria/química , Mucosa Respiratoria/citología , Mucosa Respiratoria/ultraestructura , Titanio/toxicidad
10.
Sci Total Environ ; 630: 609-617, 2018 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-29494970

RESUMEN

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.


Asunto(s)
Agricultura , Ecosistema , Monitoreo del Ambiente , Nanopartículas/análisis , Contaminantes del Suelo/análisis , Titanio/análisis , Suelo/química
11.
Burns ; 43(7): 1516-1523, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28536040

RESUMEN

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.


Asunto(s)
Quemaduras/diagnóstico por imagen , Piel/diagnóstico por imagen , Termografía/instrumentación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Quemaduras/diagnóstico , Computadoras de Mano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Reproducibilidad de los Resultados , Temperatura , Factores de Tiempo , Cicatrización de Heridas , Adulto Joven
12.
Biochimie ; 88(11): 1605-18, 2006 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16996675

RESUMEN

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.


Asunto(s)
Elementos de Series Actinoides/clasificación , Elementos de Series Actinoides/análisis , Elementos de Series Actinoides/farmacología , Elementos de Series Actinoides/toxicidad , Contaminación Ambiental , Humanos , Radioisótopos/toxicidad , Termodinámica
13.
Radiat Prot Dosimetry ; 122(1-4): 310-2, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-17218368

RESUMEN

A single ion hit facility is being developed at the Pierre Süe Laboratory (LPS) since 2004. This set-up will be dedicated to the study of ionising radiation effects on living cells, which will complete current research conducted on uranium chemical toxicity on renal and osteoblastic cells. The study of the response to an exposure to alpha particles will allow us to distinguish radiological and chemical toxicities of uranium, with a special emphasis on the bystander effect at low doses. Designed and installed on the LPS Nuclear microprobe, up to now dedicated to ion beam microanalysis, this set-up will enable us to deliver an exact number of light ions accelerated by a 3.75 MV electrostatic accelerator. An 'in air' vertical beam permits the irradiation of cells in conditions compatible with cell culture techniques. Furthermore, cellular monolayer will be kept in controlled conditions of temperature and atmosphere in order to diminish stress. The beam is collimated with a fused silica capillary tubing to target pre-selected cells. Motorisation of the collimator with piezo-electric actuators should enable fast irradiation without moving the sample, thus avoiding mechanical stress. An automated epifluorescence microscope, mounted on an antivibration table, allows pre- and post-irradiation cell observation. An ultra thin silicon surface barrier detector has been developed and tested to be able to shoot a cell with a single alpha particle.


Asunto(s)
Técnicas de Cultivo de Célula/instrumentación , Fenómenos Fisiológicos Celulares/efectos de la radiación , Separación Celular/instrumentación , Iones Pesados , Aceleradores de Partículas/instrumentación , Radiobiología/instrumentación , Radiometría/instrumentación , Técnicas de Cultivo de Célula/métodos , Separación Celular/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Francia , Laboratorios , Miniaturización , Dosis de Radiación , Radiobiología/métodos , Radiometría/métodos , Electricidad Estática , Evaluación de la Tecnología Biomédica
14.
Nanoscale ; 8(38): 17012-17021, 2016 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-27722394

RESUMEN

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.


Asunto(s)
Hepatocitos/metabolismo , Nanopartículas del Metal , Plata/análisis , Citratos , Células Hep G2 , Humanos , Iones
15.
Biochim Biophys Acta ; 1341(1): 79-86, 1997 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-9300811

RESUMEN

A cDNA clone At.MAMI (Arabidopsis thaliana membrane-associated mannitol-induced) was isolated from an Arabidopsis cDNA expression library by immunoselection. The cDNA was full-length (1.18 kb) with an open reading frame of 798 nucleotides encoding a 265 amino acid protein. The sequence of At.MAMI did not show any significant identity with other genes, as well as the deduced amino acid sequence with other proteins. However, prediction methods for the secondary structure of MAMI-30, together with homologous domains revealed some identity with VAP-33, a protein involved in membrane trafficking in neuronal tissues. In contrast to VAP-33, MAMI-30 did not exhibit a transmembrane domain, but positively charged loop regions could be involved in membrane anchoring. Indeed, MAMI-30 was immunodetected in purified plasma membrane from Arabidopsis cells. The gene was responsive to low turgor in Arabidopsis and its expression regulated developmentally. In addition, reduction of turgor caused a higher accumulation of mRNAs.


Asunto(s)
Arabidopsis/química , Proteínas de Plantas/química , Secuencia de Aminoácidos , Anticuerpos , Arabidopsis/genética , Secuencia de Bases , Membrana Celular/química , Células Cultivadas , ADN Complementario/inmunología , ADN Complementario/aislamiento & purificación , Expresión Génica , Datos de Secuencia Molecular , Presión Osmótica , Proteínas de Plantas/genética , Estructura Secundaria de Proteína , Receptores de Vitronectina/inmunología
16.
Biochim Biophys Acta ; 1435(1-2): 61-70, 1999 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-10561538

RESUMEN

A cDNA clone, AtELP1 (Arabidopsis thaliana EGF receptor-like protein) was isolated from an Arabidopsis cDNA library with an oligonucleotide probe corresponding to a highly conserved region of animal beta-integrins. The cloning of this cDNA was previously reported and it has been proposed that AtELP might be a receptor involved in intracellular trafficking. In the present work, using two specific independent sets of anti-peptide antibodies, we show that AtELP1 is mainly located in the plasma membrane, supporting another function for this protein. Structural studies, using methods for secondary structure prediction, indicated the presence of cysteine-rich domains specific to beta-integrins. Database searches revealed that AtELP1 is a member of a multigenic family composed of at least six members in A. thaliana. Northern blot analysis of AtELP1, 2b and 3 was performed on mRNA extracted from cells cultured in normal and stressed conditions, and from several organs and plants submitted to biotic or abiotic stresses. All the genes are expressed at different levels in the same conditions, but preferentially in roots, fruits and leaves in response to water deficit.


Asunto(s)
Arabidopsis/genética , Receptores ErbB/genética , Integrina beta1/genética , Secuencia de Aminoácidos , Northern Blotting , Western Blotting , Clonación Molecular , ADN Complementario/química , Regulación de la Expresión Génica de las Plantas , Integrina beta1/biosíntesis , Integrina beta1/química , Datos de Secuencia Molecular , Sondas de Oligonucleótidos/química , Análisis de Secuencia
17.
Biochim Biophys Acta ; 1483(2): 285-93, 2000 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-10634944

RESUMEN

Stable cell lines that individually express the eight known human prostanoid receptors (EP(1), EP(2), EP(3), EP(4), DP, FP, IP and TP) have been established using human embryonic kidney (HEK) 293(EBNA) cells. These recombinant cell lines have been employed in radioligand binding assays to determine the equilibrium inhibitor constants of known prostanoid receptor ligands at these eight receptors. This has allowed, for the first time, an assessment of the affinity and selectivity of several novel compounds at the individual human prostanoid receptors. This information should facilitate interpretation of pharmacological studies that employ these ligands as tools to study human tissues and cell lines and should, therefore, result in a greater understanding of prostanoid receptor biology.


Asunto(s)
Membrana Celular/metabolismo , Prostaglandinas/metabolismo , Receptores de Prostaglandina/metabolismo , Unión Competitiva , Línea Celular , Humanos , Ligandos , Ensayo de Unión Radioligante , Receptores de Prostaglandina/agonistas , Receptores de Prostaglandina/antagonistas & inhibidores , Proteínas Recombinantes/metabolismo
19.
Nanoscale ; 7(16): 7323-30, 2015 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-25824974

RESUMEN

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.


Asunto(s)
Nanopartículas del Metal/química , Compuestos de Plata/química , Plata/química , Animales , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Glutatión/química , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Nanopartículas del Metal/toxicidad , Ratones , Microscopía Electrónica de Transmisión , Espectroscopía de Absorción de Rayos X
20.
Nanoscale ; 7(16): 7352-60, 2015 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-25825056

RESUMEN

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.


Asunto(s)
Nanopartículas del Metal/química , Titanio/química , Células CACO-2 , Supervivencia Celular/efectos de los fármacos , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Transportador de Glucosa de Tipo 1/metabolismo , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Intestinos/citología , Nanopartículas del Metal/toxicidad , Especies Reactivas de Oxígeno/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA