RESUMEN
The purpose of this study is to examine whether corporate social responsibility (CSR) activities perceived by consumers affect brand trust and corporate sustainability management (CSM). In other words, this study tried to examine whether the compatibility and authenticity of CSR influences brand trust, thereby affecting CSM including economic viability, environmental soundness, and social responsibility. To measure this, an empirical analysis was conducted on 479 consumers who had experience purchasing products from cosmetic companies that are carrying out CSR. As a result of the analysis, it was found that the compatibility and authenticity of CSR have a positive effect on brand trust. Also, it was found that brand trust had a positive effect on social responsibility among the sub-concepts of CSM, but did not affect economic viability and environmental soundness. The results of this study are expected to provide strategic implications for social responsibility performance and brand trust building necessary for cosmetics companies to grow continuously.
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Ellagic acid (EA), an antioxidant polyphenolic constituent of plant origin, has been reported to possess diverse pharmacological properties, including anti-inflammatory, anti-tumor and immunomodulatory activities. This work aimed to clarify the skin anti-photoaging properties of EA in human dermal fibroblasts. The skin anti-photoaging activity was evaluated by analyzing the reactive oxygen species (ROS), matrix metalloproteinase-2 (MMP-2), total glutathione (GSH) and superoxide dismutase (SOD) activity levels as well as cell viability in dermal fibroblasts under UV-B irradiation. When fibroblasts were exposed to EA prior to UV-B irradiation, EA suppressed UV-B-induced ROS and proMMP-2 elevation. However, EA restored total GSH and SOD activity levels diminished in fibroblasts under UV-B irradiation. EA had an up-regulating activity on the UV-B-reduced Nrf2 levels in fibroblasts. EA, at the concentrations used, was unable to interfere with cell viabilities in both non-irradiated and irradiated fibroblasts. In human dermal fibroblasts, EA plays a defensive role against UV-B-induced oxidative stress possibly through an Nrf2-dependent pathway, indicating that this compound has potential skin antiphotoaging properties.
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Fusarium wilt (FW), caused by the soil-borne fungal pathogen Fusarium oxysporum is a serious disease in cruciferous plants, including the radish (Raphanus sativus). To identify quantitative trait loci (QTL) or gene(s) conferring resistance to FW, we constructed a genetic map of R. sativus using an F2 mapping population derived by crossing the inbred lines '835' (susceptible) and 'B2' (resistant). A total of 220 markers distributed in 9 linkage groups (LGs) were mapped in the Raphanus genome, covering a distance of 1,041.5 cM with an average distance between adjacent markers of 4.7 cM. Comparative analysis of the R. sativus genome with that of Arabidopsis thaliana and Brassica rapa revealed 21 and 22 conserved syntenic regions, respectively. QTL mapping detected a total of 8 loci conferring FW resistance that were distributed on 4 LGs, namely, 2, 3, 6, and 7 of the Raphanus genome. Of the detected QTL, 3 QTLs (2 on LG 3 and 1 on LG 7) were constitutively detected throughout the 2-year experiment. QTL analysis of LG 3, flanked by ACMP0609 and cnu_mBRPGM0085, showed a comparatively higher logarithm of the odds (LOD) value and percentage of phenotypic variation. Synteny analysis using the linked markers to this QTL showed homology to A. thaliana chromosome 3, which contains disease-resistance gene clusters, suggesting conservation of resistance genes between them.
Asunto(s)
Brassica/genética , Resistencia a la Enfermedad/genética , Fusarium/fisiología , Genoma de Planta/genética , Enfermedades de las Plantas/genética , Sitios de Carácter Cuantitativo/genética , Raphanus/genética , Arabidopsis/genética , Mapeo Cromosómico , Cruzamientos Genéticos , Resistencia a la Enfermedad/inmunología , Marcadores Genéticos , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/microbiología , Carácter Cuantitativo Heredable , Raphanus/inmunología , Raphanus/microbiología , Sintenía/genéticaRESUMEN
For tissue engineering and regeneration, a porous scaffold with interconnected networks is needed to guide cell attachment and growth/ingrowth in three-dimensional (3D) structure. Using a rapid prototyping (RP) technique, we designed and fabricated 3D plotting system and three types of scaffolds: those from polycaprolactone (PCL), those from PCL and hydroxyapatite (HA), and those from PCL/HA and with a shifted pattern structure (PCL/HA/SP scaffold). Shifted pattern structure was fabricated to increase the cell attachment/adhesion. The PCL/HA/SP scaffold had a lower compressive modulus than PCL and PCL/HA scaffold. However, it has a better cell attachment than the scaffolds without a shifted pattern. MTT assay and alkaline phosphatase activity results for the PCL/HA/SP scaffolds were significantly enhanced compared to the results for the PCL and PCL/HA scaffolds. According to their degree of cell proliferation/differentiation, the scaffolds were in the following order: PCL/HA/SP > PCL/HA > PCL. These 3D scaffolds will be applicable for tissue engineering based on unique plotting system.
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Huesos/metabolismo , Durapatita/química , Poliésteres/química , Ingeniería de Tejidos/métodos , Materiales Biocompatibles/química , Biotecnología/métodos , Adhesión Celular , Línea Celular Tumoral , Proliferación Celular , Diseño de Equipo , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo/métodos , Porosidad , Andamios del Tejido , Tomografía Computarizada por Rayos X/métodos , Microtomografía por Rayos X/métodosRESUMEN
PPARγ agonists exert neuroprotective effects against various types of brain injuries. In the present study, we investigated the effects of KR-62980, a new PPARγ agonist, and rosiglitazone on the neuronal cell death induced by chemical ischemia-reperfusion in SK-N-SH cells and their underlying molecular mechanisms. Both agonists inhibited chemical ischemia-reperfusion-induced cell death, and the effects were associated with anti-apoptotic action. KR-62980 and rosiglitazone suppressed NO and ROS formation, and N-acetyl-N-acetoxy-4-chlorobenzenesulfonamide, an NO generator, reversed the protective effects of the agonists on cell viability. In the agonist-induced anti-apoptotic process, PTEN expression was suppressed in parallel with increased Akt and ERK phosphorylation, whereas PD98059 (an ERK inhibitor) or wortmannin (a PI-3K inhibitor) abolished the cell survival by KR-62980 and rosiglitazone. All of the effects of KR-62980 and rosiglitazone appeared to be PPARγ-dependent because the effects were reversed by bisphenol A diglycidyl ether, a PPARγ antagonist, or by PPARγ knockdown. Our results demonstrate that two PPARγ agonists, KR-62980 and rosiglitazone, inhibited chemical ischemia-reperfusion-induced neuronal cell death by PPARγ-mediated anti-apoptotic and anti-oxidant mechanisms related to PTEN suppression and ERK phosphorylation.
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Indenos/farmacología , Morfolinas/farmacología , Fármacos Neuroprotectores/farmacología , PPAR gamma/agonistas , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Inhibidores Enzimáticos/farmacología , Humanos , Neuroblastoma/patología , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Compuestos Orgánicos/farmacología , Fosforilación/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Rosiglitazona , Transducción de Señal/efectos de los fármacos , Azida Sódica/farmacología , Tiazolidinedionas/farmacología , Factores de TiempoRESUMEN
A new series of cyclic sulfonamide derivatives was synthesized and evaluated for their ability to inhibit 11beta-HSD1. Cyclic sulfonamides with phenylacetyl substituents at the 2-position showed nanomolar inhibitory activities. Among them, compound 4e exhibited a good in vitro inhibitory activity and selectivity toward human 11beta-HSD2.
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11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1/antagonistas & inhibidores , Descubrimiento de Drogas/métodos , Sulfonamidas/síntesis química , 11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 1/metabolismo , Animales , Línea Celular , Humanos , Ratones , Microsomas/efectos de los fármacos , Microsomas/enzimología , Sulfonamidas/metabolismo , Sulfonamidas/farmacologíaRESUMEN
In this study, we present in vitro cytotoxicity of iron oxide (Fe(3)O(4)) and manganese oxide (MnO) using live/dead cell assay, lactate dehydrogenase assay, and reactive oxygen species detection with variation of the concentration of nanoparticles (5-500 microg/ml), incubation time (18-96 h), and different human cell lines (lung adenocarcinoma, breast cancer cells, and glioblastoma cells). The surface of nanoparticles is modified with polyethyleneglycol-derivatized phospholipid to enhance the biocompatibility, water-solubility, and stability under an aqueous media. While the cytotoxic effect was negligible for 18 h incubation even at highest concentration of 500 microg/ml, MnO nanoparticle represented higher level of toxicity than those of Fe(3)O(4) and the commercial medical contrast reagent, Feridex after 2 and 4 day incubation time. However, the cytotoxicity of Fe(3)O(4) is equivalent or better than Feridex based on the live/dead cell viability assay. The engineered MnO and Fe(3)O(4) exhibited excellent stability compared with Feridex for a prolonged incubation time.
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Bioensayo/métodos , Compuestos Férricos/efectos adversos , Compuestos de Manganeso/efectos adversos , Ensayo de Materiales/métodos , Nanopartículas/efectos adversos , Óxidos/efectos adversos , Técnicas de Cultivo de Célula , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Humanos , Factores de TiempoRESUMEN
The purpose of this study was to evaluate recording completeness of the nursing process. We compared nursing statements documented at the time when the Electronic Nursing Record (ENR) system, based on the ICNP, was implemented in 2004 with those documented in 2007. The ENRs for 35 gastrectomy patients in each year were selected for evaluation. The selected data were 11,822 nursing statements in 2004 and 27,870 in 2007. The results indicated a significant increase in the completeness of the nursing process in 2007. In addition, the number of nursing diagnosis increased by 5.1 times. The most contributing factor for this increase is assumed to be nurse education.
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Gastrectomía/enfermería , Sistemas de Registros Médicos Computarizados , Proceso de Enfermería/normas , Estudios de Evaluación como Asunto , HumanosRESUMEN
Obesity is one of the potential risk factors in causing breast cancer. As a result, adipose tissue surrounding breast ductal cells may play an important role in the breast cancer development or progression. To identify the genes that are regulated by factors secreted from adipocytes in breast cancer cells, MDA-MB-231 cells were treated with the culture medium of adipocytes. Most of induced genes were related to immune function and wound healing, which share a common gene expression signature with cancer progression. In present study macrophage inhibitory cytokine 1 (MIC-1) gene was studied among the induced genes. It was found that both MIC-1 mRNA and protein were dramatically increased by the culture medium of adipocytes. Furthermore, proteinase K-treated adipocyte culture supernatants also induced MIC-1 expression. These findings indicate that proteins are not major MIC-1 inducing factors in adipocyte culture medium. Consequently, we examined the effect of free fatty acids such as palmitate and oleate on MIC-1 induction and found that palmitate markedly induced MIC-1 gene expression, whereas oleate did not. Adipocyte culture medium- and palmitate-induced MIC-1 gene expression was mediated by the activation of p38 MAPK, but not by the activation of JNK, ERK, and NF-kappaB pathway. In addition, adipocyte-CM-induced MIC-1 also increased invasiveness of MDA-MB-231 cells.
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Adipocitos/citología , Neoplasias de la Mama/metabolismo , Citocinas/metabolismo , Animales , Western Blotting , Neoplasias de la Mama/patología , Movimiento Celular , Células Cultivadas , Medios de Cultivo/farmacología , Citocinas/genética , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Factor 15 de Diferenciación de Crecimiento , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Ratones , Análisis por Micromatrices , FN-kappa B/genética , FN-kappa B/metabolismo , Células 3T3 NIH , Invasividad Neoplásica , Palmitatos/farmacología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Cicatrización de Heridas , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
In the apatite coatings on Ti the heat treatment process is necessary to crystallize the apatite structure for improved chemical stability and biological properties. However, the heat treatment normally degrades the mechanical strength of the coating layer associated with thermally induced stress. In this study, we aimed to improve the crystallization of apatite coating by using calcium fluoride (CaF2) as a buffer layer. The insertion of a thin layer of CaF2 (0.2-1 microm) between apatite and Ti significantly improved the crystallization behavior of apatite. Moreover, this crystallization was more enhanced as the thickness of CaF2 was increased. When a 1 microm-thick CaF2 was inserted, the crystallization of apatite initiated at a temperature as low as 320 degrees C, being a dramatic improvement in the crystallization when considering the crystallization initiation temperature of a bare apatite coating on Ti was approximately 450 degrees C. As a result of this crystallization enhancement, the dissolution behavior of CaF2-inserted apatite coatings was more stable than that of the bare apatite coating, showing much reduced initial-burst effect. Preliminary cellular assay showed the CaF2-inserted apatite coating provided a substrate for cells to spread and grow favorably, as being similar to the bare apatite coating. This novel way of apatite coating on Ti using CaF2 buffer layer may be useful in the coating systems particularly requiring low temperature processing and increased crystallinity with high chemical stability.
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Apatitas/química , Fluoruro de Calcio/química , Titanio/química , Tampones (Química) , Cristalización , Calor , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Modelos Químicos , Osteoblastos/metabolismo , Estrés Mecánico , Temperatura , Resistencia a la Tracción , Factores de Tiempo , Difracción de Rayos XRESUMEN
A novel method of coating a polymeric scaffold with a dense ceramic layer was developed. This method exploits the fact that only one of the two interlaced 3-D channels formed in a ceramic dual-scaffold can be infiltrated with a polymer. Firstly, a 3-D graphite network prepared by the rapid prototyping (RP) method was dip-coated with hydroxyapatite (HA) slurry, followed by heat-treatment at 1250 degrees C for 3 h in air. This created an additional 3-D channel through the removal of the graphite network, while preserving the pre-existing 3-D channel. Thereafter, only one channel was infiltrated with a molten poly(epsilon-caprolactone) (PCL) polymer at 140 degrees C for 12 h, producing a PCL scaffold with a dense, uniform HA coating layer. The sample showed high compressive strength with ductile behavior, due to the nature of the PCL polymer, and an excellent cellular response afforded by the bioactive HA coating layer. The results indicate that this novel technique provides a highly versatile method of coating various polymeric scaffolds with bioactive layers in order to endow them with advanced functionalities.
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Materiales Biocompatibles Revestidos/síntesis química , Materiales Biocompatibles Revestidos/farmacología , Durapatita/química , Osteoblastos/citología , Osteoblastos/fisiología , Poliésteres/química , Ingeniería de Tejidos/métodos , Adhesión Celular/fisiología , Técnicas de Cultivo de Célula/métodos , Línea Celular , Supervivencia Celular/fisiología , Cerámica/química , Cristalización/métodos , Durapatita/administración & dosificación , Humanos , Ensayo de Materiales , Propiedades de SuperficieRESUMEN
A novel scaffold designed for tissue engineering applications, which we refer to as a "dual-scaffold" because its structure consists of two interlaced three-dimensional (3-D) hydroxyapatite (HA) networks, was fabricated using a combination of the rapid prototyping (RP) method and dip-coating process. To accomplish this, a graphite network acting as a template was prepared using the RP method and then uniformly dip-coated with HA slurry. The resultant sample was then heat-treated at 1250 degrees C for 3 h in air to remove the graphite network and consolidate the HA networks. An additional 3-D channel was formed by removing the graphite network, while preserving the pre-existing channel. The unique structure of the dual-scaffold endows it with unprecedented features, such as ultra-high porosity (>85%), a high surface area and high compressive strength, as well as a tightly controlled pore structure. In addition, an excellent cellular response was observed to the fabricated HA dual-scaffold.
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Sustitutos de Huesos/química , Durapatita/química , Fuerza Compresiva , Grafito/química , Ensayo de Materiales , Porosidad , Propiedades de Superficie , Ingeniería de TejidosRESUMEN
The major soy isoflavones are daidzin and genistin, the glycoside conjugates of daidzein (DZ) and genistein (GTN). After ingestion, they are metabolized into diverse compounds in the gut. The marked inter-individual variation has been suggested in their metabolism. The clinical effects may be modulated by the metabolic ability to produce a more potent metabolite than the precursor. Our study was, therefore, designed to analyze and compare in vitro biologic activities of their metabolites: DZ, GTN, dihydrogenistein (DGTN), dihydrodaidzein (DDZ), tetrahydrodaidzein (TDZ), O-desmethylangolensin (ODMA), and equol (EQL). Furthermore, we investigated their modulatory effects in the presence of estrogen using several in vitro systems. The intermediate metabolites, such as DGTN, DDZ, and TDZ, bind much weakly to both ERs and induce less potently in transcriptional activity, gene expression, and mammary cell proliferation than their precursors. EQL has the strongest binding affinities and estrogenic activities especially for ERbeta among the daidzin metabolites and shows the ability to suppress osteoclast formation at high doses. The test isoflavonoids act like estrogen antagonists with the premenopausal dose of E2 and thus inhibit estrogenic actions by E2, whereas they exert estrogen agonist activity with the lower dose of estrogen close to the serum levels of postmenopausal women. Our results suggest that phytoestrogens such as isoflavones may exert their effects as estrogen antagonists in a high estrogen environment, or they may act as estrogen agonists in a low estrogen environment.
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Estrógenos/agonistas , Isoflavonas/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular , Receptor alfa de Estrógeno/genética , Receptor alfa de Estrógeno/metabolismo , Receptor beta de Estrógeno/genética , Receptor beta de Estrógeno/metabolismo , Humanos , Isoflavonas/metabolismo , Ratones , Estructura Molecular , Osteoclastos/fisiología , Transcripción Genética , TransfecciónRESUMEN
A hydroxyapatite (HA)-titania (TiO(2)) hybrid coating is developed to improve the biocompatibility of titanium (Ti) implants. The HA predeposited layer on Ti via electron beam (e-beam) evaporation is subsequently treated by micro-arc oxidation (MAO) to produce an HA-TiO(2) hybrid layer on Ti. The e-beam-deposited HA layer has a thickness of approximately 1 microm and was highly dense prior to MAO. By means of MAO treatment, a rough and porous TiO(2) layer is formed beneath the HA layer with a simultaneous local dissolution of the HA layer. Due to the HA precoating, high concentrations of Ca and P are preserved on the coating surface. The osteoblast-like cells on the hybrid coating layer grow and spread favorably. The cell proliferation rate on the hybrid coatings is not much different from that on pure Ti or simple MAO-treated Ti. However, the alkaline phosphatase (ALP) activity of the cells is significantly higher (p < 0.05) on the HA-TiO(2) hybrid coatings than on either the pure Ti or the simple MAO-treated specimen, suggesting that the cellular activity on the hybrid coatings is improved.
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Materiales Biocompatibles Revestidos/química , Durapatita/química , Oseointegración/fisiología , Osteoblastos/citología , Osteoblastos/fisiología , Prótesis e Implantes , Titanio/química , Línea Celular , Proliferación Celular , Supervivencia Celular , Humanos , Ensayo de Materiales , Propiedades de SuperficieRESUMEN
Collagen, as a major constituent of human connective tissues, has been regarded as one of the most important biomaterials. As a coating moiety on Ti hard-tissue implants, the collagen has recently attracted a great deal of attention. This article reports the effects of fibrillar assembly and crosslinking of collagen on its chemical stability and the subsequent osteoblastic responses. The fibrillar self-assembly of collagen was carried out by incubating acid-dissolved collagen in an ionic-buffered medium at 37 degrees C. The degree of assembly was varied with the incubation time and monitored by the turbidity change. The differently assembled collagen was coated on the Ti and crosslinked with a carbodiimide derivative. The partially assembled collagen contained fibrils with varying diameters as well as nonfibrillar aggregates. On the other hand, the fully assembled collagen showed the complete formation of fibrils with uniform diameters of approximately 100-200 nm with periodic stain patterns within the fibrils, which are typical of native collagen fibers. Through this fibrillar assembly, the collagen coating had significantly improved chemical stability in both the saline and collagenase media. The subsequent crosslinking step also improved the stability of the collagen coating, particularly in the unassembled collagen. The fibrillar assembly and the crosslinking of collagen significantly influenced the osteoblastic cell responses. Without the assembly, the collagen layer on Ti adversely affected the cell attachment and proliferation. However, those cellular responses were improved significantly when the collagen was assembled to fibrils and the assembly degree was increased. After crosslinking the collagen coating, these cellular responses were significantly enhanced in the case of the unassembled collagen but were not altered much in the assembled collagen. Based on these observations, it is suggested that the fibrillar assembly and the crosslinking of collagen require careful considerations in the collagen administration as a coating moiety.
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Colágeno/química , Osteoblastos/citología , Línea Celular , Colágeno/ultraestructura , Humanos , Microscopía Electrónica de Rastreo , Microscopía Electrónica de TransmisiónRESUMEN
The purpose of this study was to develop a new method of releasing fluorine in a controlled manner for applications in the field of orthodontic Ti-based wire, namely the coating of fluorides on Ti. Thin films of two fluoride compounds, CaF(2) and MgF(2), were coated on Ti via the electron-beam evaporation method. The fluorine was released rapidly from the as-deposited MgF(2) coating within a short period(,) and then the release rate slowed down. When the MgF(2) coating was heat treated, this initial burst effect was decreased, but a significant amount of cracks were generated. On the other hand, in the case of the as-deposited CaF(2) coating, fluorine was released linearly for the entire period, without an initial burst. In the heat-treated CaF(2) coatings the trend was similarly observed. The linear fluorine release from the CaF(2) coatings, even in the as-deposited state, was attributed to the high degree of crystallinity of the coatings. A preliminary cell test showed favorable cell viability on both the fluoride coatings. Given their sustained and controlled fluorine release, these fluoride coatings, particularly CaF(2), are suggested to be potentially useful in the field of orthodontic Ti-based wire.
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Sistemas de Liberación de Medicamentos/instrumentación , Fluoruros/química , Flúor/administración & dosificación , Flúor/química , Alambres para Ortodoncia , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular , Humanos , Microscopía Electrónica de Rastreo , Difracción de Rayos XRESUMEN
A thin hydroxyapatite (HA) layer was coated on a microarc oxidized titanium (MAO-Ti) substrate by means of the sol-gel method. The microarc oxidation (anodizing) enhanced the biocompatibility of the Ti, and the bioactivity was improved further by the sol-gel HA coating on the anodized Ti. The HA sol was aged fully to obtain a stable and phase-pure HA, and the sol concentration was varied to alter the coating thickness. Through the sol-gel HA coating, the Ca and P concentrations in the coating layer increased significantly. However, the porous morphology and roughness of the MAO-Ti was altered very little by the sol-gel treatment. The proliferation and alkaline phosphatase (ALP) activity of the osteoblast-like cells on the MAO/HA sol-gel-treated Ti were significantly higher than those on the MAO-Ti without the HA sol-gel treatment.
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Implantes Absorbibles , Durapatita/química , Titanio/química , Titanio/farmacología , Fosfatasa Alcalina/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxidación-ReducciónRESUMEN
In this report, a series of fluoridated apatite coatings were obtained by the electron-beam deposition method. The fluoridation of the apatite was aimed to improve the stability of the coating and elicit the fluorine effect, which is useful in the dental restoration area. Apatites fluoridated at different levels were used as initial evaporants for the coatings. The as-deposited coatings were amorphous, but after heat treatment at 500 degrees C for 1 h, the coatings crystallized well to an apatite phase without forming any cracks. The adhesion strengths of the as-deposited coatings were about 40 MPa. After heat treatment at 500 degrees C, the strengths of the pure HA and FA coatings decreased to about 20 MPa, however, the partially fluoridated coatings maintained their initial strength. The dissolution rate of the fluoridated coatings was lower than that of the pure HA coating, and the rate was the lowest in the coatings with 25% and 50% fluorine substitutions. The osteoblast-like cells responded to the coatings in a similar manner to the dissolution behavior. The cells on the fluoridated coatings showed a lower (p < 0.05) proliferation level compared to those on the pure HA coating. The alkaline phosphatase activity of the cells was slightly lower than that on the pure HA coating, but this difference was not statistically significant.
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Líquidos Corporales/química , Materiales Biocompatibles Revestidos/química , Cristalización/métodos , Hidroxiapatitas/química , Osteosarcoma/patología , Osteosarcoma/fisiopatología , Titanio/química , Implantes Absorbibles , Adhesividad , Adhesión Celular , Diferenciación Celular , Línea Celular Tumoral , Proliferación Celular , Tamaño de la Célula , Materiales Biocompatibles Revestidos/análisis , Electrones , Dureza , Calor , Humanos , Hidroxiapatitas/análisis , Propiedades de SuperficieRESUMEN
Fluorapatite (FA)-collagen composites were synthesized via a biomimetic coprecipitation method in order to improve the structural stability and cellular responses. Different amounts of ammonium fluoride (NH4F), acting as a fluorine source for FA, were added to the precipitation of the composites. The precipitated composites were freeze-dried and isostatically pressed in a dense body. The added fluorine was incorporated nearly fully into the apatite structure (fluoridation), and a near stoichiometric FA-collagen composite was obtained with complete fluoridation. The freeze-dried composites had a typical biomimetic network, consisting of collagen fibers and precipitates of nano-sized apatite crystals. The human osteoblast-like cells on the FA-collagen composites exhibited significantly higher proliferation and differentiation (according to alkaline phosphatase activity) than those on the hydroxyapatite-collagen composite. These enhanced osteoblastic cell responses were attributed to the fluorine release and the reduced dissolution rate.
Asunto(s)
Apatitas/química , Sustitutos de Huesos/química , Colágeno/química , Durapatita/química , Fluoruros/química , Flúor/química , Fosfatasa Alcalina/metabolismo , Compuestos de Amonio , Biomimética , Calcio/química , Fosfatos de Calcio/química , Diferenciación Celular , Proliferación Celular , Matriz Extracelular/metabolismo , Humanos , Iones , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Osteoblastos/metabolismo , Compuestos de Amonio Cuaternario , Temperatura , Factores de Tiempo , Difracción de Rayos XRESUMEN
The biocompatibility of zirconia-alumina (ZA) nano-composites in load-bearing applications such as dental/orthopedic implants was significantly enhanced by the addition of bioactive HA. The ZA matrix was composed of nano-composite powder obtained from the Pechini process and had higher flexural strength than conventionally mixed zirconia-alumina composite. Because the ZA nano-composite powder effectively decreased the contact area between HA and zirconia for their reaction during the sintering process, the HA-added ZA nano-composites contained biphasic calcium phosphates (BCP) of HA/TCP and had higher flexural strength than conventionally mixed ZA-HA composite. From the in vitro test with osteoblastic cell-lines, the proliferation and the differentiation (as expressed by the alkaline phosphatase activity) of the cellular response on the HA-added ZA nano-composites gradually increased as the amount of HA added increased. From the mechanical and biological evaluations of the HA-added ZA nano-composites, 30HA (30 vol% HA + 70 vol% ZA) was found to be the optimal composition for load-bearing biological applications.