Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
Mais filtros










Base de dados
Tipo de estudo
Intervalo de ano de publicação
1.
ChemMedChem ; 15(2): 247-255, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31773850

RESUMO

Targeting the tumor cell mitochondrion could produce novel anticancer agents. We designed an aryl-urea fatty acid (1 g; 16({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid) that disrupted the mitochondrion and decreased MDA-MB-231 breast cancer cell viability. To optimize the aryl-ureas the present study evaluated mitochondrial targeting by 1 g analogues containing alkyl chains between 10-17 carbons. Using the dye JC-1, the C12-C17 analogues efficiently disrupted the mitochondrial membrane potential (IC50 s 3.5±1.2 to 7.6±1.1 µM) and impaired ATP production; shorter analogues were less active. 7-Aminoactinomycin D/annexin V staining and flow cytometry showed that these agents activated the killing mechanisms of necrosis and apoptosis to varying extents (7-aminoactinomycin D/annexin V staining ratios 4.3-6.0). Indeed, 1 g and its C17 analogue preferentially activated necrosis and apoptosis, respectively (ratios 2.1 and 16). Taken together, alkyl chain length is a determinant of mitochondrial targeting by aryl-ureas and can be varied to develop analogues that activate apoptosis or necrosis in a regulated fashion.

2.
Chem Commun (Camb) ; 55(76): 11410-11413, 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31482869

RESUMO

Graphene-based composite materials are versatile but not easily procurable. Cyanobacterial cells, an outgrowth of eutrophic freshwater lake, were simultaneously employed as a template for the growth of ZnO nanoparticles and as a biomass carbon source for graphene sheets, resulting in chlorophyll-containing graphene-wrapped ZnO nanospheres.


Assuntos
Cianobactérias/química , Cianobactérias/citologia , Grafite/química , Nanosferas/química , Óxido de Zinco/química , Clorofila/química
3.
Nanomaterials (Basel) ; 9(5)2019 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-31060270

RESUMO

N-doped TiO2 with oxygen vacancies exhibits many advantages for photocatalysis, such as enhanced visible light absorbency, inhibition of the photogenerated charge carrier recombination, etc. However, preparation of N-doped TiO2 with oxygen vacancies under mild conditions is still a challenge. Herein, N-doped TiO2 nanospheres with tetrahedral Ti4+ sites were synthesized by using dodecylamine as template and assisted by l-alanine acids. The obtained samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Vis diffuse reflectance spectra (UV-Vis DRS). It was found that the dodecylamine as a neutral surfactant controlled the structure of TiO2 spherical, while l-alanine acids provided a nitrogen source. The existence of tetrahedral Ti4+ sites in N-doped TiO2 was also confirmed. The N-doped TiO2 sample with tetrahedral Ti4+ sites exhibited significantly improved photocatalytic performance for degradation of methylene blue solution under UV light or visible light irradiation. A combined time-resolved infrared (IR) spectroscopy study reveals that the enhanced photocatalytic performance could be attributed to a large amount of photogenerated charge carriers and efficient charge separation. It is demonstrated that the shallow donor state produced by oxygen vacancies of tetrahedral Ti4+ sites can effectively promote separation of charge carriers besides capturing electrons.

4.
Eur J Pharm Sci ; 129: 87-98, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30597206

RESUMO

We recently developed a novel aryl-urea fatty acid (CTU; 16({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid) that impaired the viability of MDA-MB-231 breast cancer cells in vitro and in mouse xenograft models in vivo. At present there is a deficiency of information on the structural requirements for the activity of CTU. Our initial study suggested that electron withdrawing groups were required on the aryl ring, and in this study we further evaluated the influence of the electronic properties of aromatic substitution on the capacity of CTU analogues to decrease MDA-MB-231 breast cancer cell viability. Analogues that contained strong electron-withdrawing groups in the meta- and para-positions of the aryl ring exhibited improved activity over CTU. Effective analogues down-regulated the cyclins D1, E1 and B1, and the cyclin-dependent kinases (CDKs) 4 and 6, that form complexes to coordinate cell cycle progression. Active CTU analogues also stimulated the phosphorylation and activation of the p38 MAP kinase signalling pathway in cells and both decreased proliferation (5-bromo-2'-deoxyuridine (brdU) incorporation) and activated apoptosis (executioner caspase-3/7 activity). These agents offer a new approach to target the cell cycle at multiple phases in order to efficiently prevent cancer cell expansion. Inclusion of the present structural information in drug design approaches could enhance the development of optimal analogues of aryl-urea fatty acids as potential anti-cancer agents.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Sobrevivência Celular/efeitos dos fármacos , Ciclinas/metabolismo , Ácidos Graxos/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Ureia/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinases Ciclina-Dependentes/metabolismo , Regulação para Baixo/efeitos dos fármacos , Feminino , Humanos , Fosforilação/efeitos dos fármacos
5.
Nanomaterials (Basel) ; 8(10)2018 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-30322115

RESUMO

Lipid-based drugs are emerging as an interesting class of novel anticancer drugs with the potential to target specific cancer cell metabolic pathways linked to their proliferation and invasiveness. In particular, ω-3 polyunsaturated fatty acids (PUFA) derivatives such as epoxides and their bioisosteres have demonstrated the potential to suppress growth and promote apoptosis in triple-negative human breast cancer cells MDA-MB-231. In this study, 16-(4'-chloro-3'-trifluorophenyl)carbamoylamino]hexadecanoic acid (ClFPh-CHA), an anticancer lipid derived from ω-3,17,18-epoxyeicosanoic acid, was formulated as a stable nanoemulsion with size around 150 nm and narrow droplet size distribution (PDI < 0.200) through phase-inversion emulsification process followed by high pressure homogenization in view of an oral administration. The ClFPh-CHA-loaded nanoemulsions were able to significantly decrease the relative tumor volume in mice bearing an intramammary tumor xenograft at all doses tested (2.5, 10 and 40 mg/kg) after 32 days of daily oral administration. Furthermore, absolute tumor weight was decreased to 50% of untreated control at 10 and 40 mg/kg, while intraperitoneal administration could achieve a significant reduction only at the highest dose of 40 mg/kg. Results suggest that oral administration of ClFPh-CHA formulated as a nanoemulsion has a sufficient bioavailability to provide an anticancer effect in mice and that the activity is at least equal if not superior to that obtained by a conventional parenteral administration of equivalent doses of the same drug.

6.
Huan Jing Ke Xue ; 39(8): 3677-3688, 2018 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-29998674

RESUMO

Stream ecosystems are the primary receivers of nutrients and organic carbon exported from terrestrial ecosystems and are profoundly influenced by the land of the surrounding landscape. Anthropogenic activities increased the nutrient and organic carbon levels in both stream and benthic biofilms, which are closely related to the differences in the N-DAMO (Nitrate/nitrite-dependent anaerobic methane oxidation) bacterial communities. We studied N-DAMO bacterial communities in streams flowing through anthropogenic land in the city of Beijing. The results showed that anthropogenic activities increase the nutrient and organic carbon levels both midstream and downstream; these are closely related to the difference in the N-DAMO bacterial communities. Phylogenetic analysis revealed that most of the cloned 16S rRNA and pmoA sequences in the North Canal were similar to those recovered from activated sludge and wastewater. The effect of nitrogen on N-DAMO bacteria in the North Canal mainly depended on the main form of available nitrogen and the source of pollutant. Moreover, N-DAMO bacteria present downstream of the North Canal, had a more connected and modular microbial network than those present midstream, where bacterial communities with tightly connected species that were shown to be more vulnerable and sensitive to various disturbances were found.


Assuntos
Bactérias/classificação , Biodiversidade , Água Doce/microbiologia , Poluentes Químicos da Água/análise , Anaerobiose , Pequim , Genes Bacterianos , Metano , Nitratos , Nitritos , Oxirredução , Filogenia , RNA Ribossômico 16S
7.
J Med Chem ; 60(20): 8661-8666, 2017 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-28921987

RESUMO

Cancer cell mitochondria are promising anticancer drug targets because they control cell death and are structurally and functionally different from normal cell mitochondria. We synthesized arylurea fatty acids and found that the analogue 16-({[4-chloro-3-(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid (13b) decreased proliferation and activated apoptosis in MDA-MB-231 breast cancer cells in vitro and in vivo. In mechanistic studies 13b emerged as the prototype of a novel class of mitochondrion-targeted agents that deplete cardiolipin and promote cancer cell death.


Assuntos
Neoplasias da Mama/patologia , Ácidos Graxos/farmacologia , Mitocôndrias/efeitos dos fármacos , Ureia/química , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Ácidos Graxos/química , Feminino , Humanos , Camundongos , Membranas Mitocondriais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
8.
FASEB J ; 31(12): 5246-5257, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28798154

RESUMO

A saturated analog of the cytochrome P450-mediated ω-3-17,18-epoxide of ω-3-eicosapentaenoic acid (C20E) activated apoptosis in human triple-negative MDA-MB-231 breast cancer cells. This study evaluated the apoptotic mechanism of C20E. Increased cytosolic cytochrome c expression and altered expression of pro- and antiapoptotic B-cell lymphoma-2 proteins indicated activation of the mitochondrial pathway. Caspase-3 activation by C20E was prevented by pharmacological inhibition and silencing of the JNK and p38 MAP kinases (MAPK), upstream MAPK kinases MKK4 and MKK7, and the upstream MAPK kinase kinase apoptosis signal-regulating kinase 1 (ASK1). Silencing of the death receptor TNF receptor 1 (TNFR1), but not Fas, DR4, or DR5, and the adapters TRADD and TNF receptor-associated factor 2, but not Fas-associated death domain, prevented C20E-mediated apoptosis. B-cell lymphoma-2 homology 3-interacting domain death agonist (Bid) cleavage by JNK/p38 MAPK linked the extrinsic and mitochondrial pathways of apoptosis. In further studies, an antibody against the extracellular domain of TNFR1 prevented apoptosis by TNF-α but not C20E. These findings suggest that C20E acts intracellularly at TNFR1 to activate ASK1-MKK4/7-JNK/p38 MAPK signaling and to promote Bid-dependent mitochondrial disruption and apoptosis. In in vivo studies, tumors isolated from C20E-treated nu/nu mice carrying MDA-MB-231 xenografts showed increased TUNEL staining and decreased Ki67 staining, reflecting increased apoptosis and decreased proliferation, respectively. ω-3-Epoxy fatty acids like C20E could be incorporated into treatments for triple-negative breast cancers.-Dyari, H. R. E., Rawling, T., Chen, Y., Sudarmana, W., Bourget, K., Dwyer, J. M., Allison, S. E., Murray, M. A novel synthetic analogue of ω-3 17,18-epoxyeicosatetraenoic acid activates TNF receptor-1/ASK1/JNK signaling to promote apoptosis in human breast cancer cells.


Assuntos
Ácidos Araquidônicos/farmacologia , Ácidos Araquidônicos/uso terapêutico , Neoplasias da Mama/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , MAP Quinase Quinase Quinase 5/metabolismo , Receptores do Fator de Necrose Tumoral/metabolismo , Animais , Apoptose/genética , Apoptose/fisiologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Caspase 3/metabolismo , Linhagem Celular Tumoral , Feminino , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/genética , MAP Quinase Quinase Quinase 5/genética , Camundongos , Camundongos Endogâmicos BALB C , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Receptores do Fator de Necrose Tumoral/genética , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Proteína de Domínio de Morte Associada a Receptor de TNF/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Receptor fas/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
9.
Biochem Pharmacol ; 143: 79-89, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-28756208

RESUMO

Cytochrome P450 2J2 (CYP2J2) expression is elevated in breast and other tumours, and is known to be protective against cytotoxic agents that may be used in cancer chemotherapy. This study evaluated the mechanisms by which MDA-MB-468 breast cancer cells that stably expressed CYP2J2 (MDA-2J2 cells) were protected against killing by the anti-cancer agent paclitaxel. Compared to control cells caspase-3/7 activation by paclitaxel was lower in MDA-2J2 cells, while cell proliferation and colony formation following paclitaxel treatment were increased. Basal lipid peroxidation was lower in MDA-2J2 cells than in control cells, and the paclitaxel-mediated increase in peroxidation was attenuated. The mitochondrial complex III inhibitor antimycin A modulated basal and paclitaxel-activated reactive oxygen species (ROS) formation in control cells; paclitaxel-activated ROS production was also modulated by the NADPH oxidase inhibitor diphenyleneiodonium. Paclitaxel increased the formation of protein adducts by the reactive aldehyde 4-hydroxynonenal that is produced by lipid peroxidation; adduct formation was attenuated in MDA-2J2 cells. ALDH1A1 expression and activity was strongly upregulated in MDA-2J2 cells that was attributed to CYP2J2-derived 14,15-epoxyeicosatrienoic acid (14,15-EET); the 8,9- and 11,12-EET regioisomers did not activate ALDH1A1 expression. Silencing of ALDH1A1 restored the sensitivity of MDA-2J2 cells to paclitaxel, as indicated by a more pronounced decrease in proliferation, and greater increases in caspase activity and formation of ROS to levels comparable with control cells. Similar findings were observed with doxorubicin, sorafenib and staurosporine, that also promoted ROS-mediated cell death that was attenuated in MDA-2J2 cells and reversed by ALDH1A1 gene silencing. These findings implicate ALDH1A1 as an important gene that is activated in MDA-MB-468-derived cells that contain high levels of CYP2J2. ALDH1A1 modulates the production of ROS by anti-cancer agents such as paclitaxel and diminishes their efficacy. Future approaches could adapt this information to facilitate the targeting of ALDH1A1 to promote the efficacy of ROS-generating cytotoxic agents and enhance the treatment of breast cancer.


Assuntos
Aldeído Desidrogenase/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Sistema Enzimático do Citocromo P-450/genética , Paclitaxel/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Aldeído Desidrogenase/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Expressão Gênica/efeitos dos fármacos , Inativação Gênica , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , RNA Interferente Pequeno/genética , Retinal Desidrogenase , Transfecção
10.
Tissue Eng Part A ; 23(21-22): 1212-1220, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28346798

RESUMO

Mesenchymal stem cells (MSCs) have been widely used for tissue repair and regeneration. However, the inherent drawbacks, including limited cell survival after cell transplantation, have hindered direct MSC transplantation for tissue repair and regeneration. The aim of this study was to investigate if exosomes isolated from MSCs can promote the proliferation and differentiation of human primary osteoblastic cells (HOBs) and be potentially used for bone tissue regeneration. We showed that adipose tissue-derived MSC (ASC)-derived exosomes (ASC-EXO) were able to promote the proliferation and osteogenic differentiation in HOBs; and the trophic effects of ASC-EXO on HOBs were further harnessed when ASCs were preconditioned with tumor necrosis factor-alpha (TNF-α) for 3 days, which mimics the acute inflammatory phase upon bone injury. In addition, we showed that Wnt-3a content was elevated in ASC-EXO when ASCs were preconditioned by TNF-α, and inhibiting Wnt signaling decreased the osteogenic gene expression levels in HOBs which were cultured in TNF-α preconditioned ASCs conditioned medium. In conclusion, it was demonstrated that ASC-EXO, especially primed by TNF-α preconditioning on ASCs, offer a promising approach to replace direct stem cell transplantation for bone repair and regeneration.


Assuntos
Tecido Adiposo/citologia , Regeneração Óssea/efeitos dos fármacos , Exossomos/metabolismo , Células-Tronco/citologia , Fator de Necrose Tumoral alfa/farmacologia , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Endocitose/efeitos dos fármacos , Exossomos/efeitos dos fármacos , Humanos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteogênese/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Proteína Wnt3A/metabolismo
11.
Appl Microbiol Biotechnol ; 101(8): 3379-3391, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27942905

RESUMO

Bacterial and archaeal assemblages are one of the most important contributors to the recycling of nutrients and the decomposition of organic matter in aquatic sediments. However, their spatiotemporal variation and its driving factors remain unclear, especially for drinking reservoirs, which are strongly affected by human consumption. Using quantitative PCR and Illumina MiSeq sequencing, we investigated the bacterial and archaeal communities in the sediments of a drinking reservoir, the Miyun Reservoir, one of the most important drinking sources for Beijing City. The abundance of bacteria and archaea presented no spatiotemporal variation. With respect to community diversity, visible spatial and temporal differences were observed in archaea, whereas the bacterial community showed minor variation. The bacterial communities in the reservoir sediment mainly included Proteobacteria, Bacteroidetes, Nitrospirae, Acidobacteria, and Verrucomicrobia. The bacterial community structure showed obvious spatial variation. The composition of the bacterial operational taxonomic units (OTUs) and main phyla were dam-specific; the composition of samples in front of the dam were significantly different from the composition of the other samples. The archaeal communities were mainly represented by Woesearchaeota and Euryarchaeota. Distinctly spatial and seasonal variation was observed in the archaeal community structure. The sediment NH4+-N, pH, and water depth were identified as the key driving factors of changes in the composition of the bacterial and archaeal communities. Water depth might have the greatest influence on the microbial community structure. The dam-specific community structure may be related to the greater water depth in front of the dam. This finding indicates that water depth might be the greatest contributor to the microbial community structure in the Miyun Reservoir.


Assuntos
Archaea/genética , Água Potável/microbiologia , Euryarchaeota/genética , Sedimentos Geológicos/microbiologia , Consórcios Microbianos , Proteobactérias/genética , Archaea/classificação , Archaea/isolamento & purificação , Pequim , Biodiversidade , Euryarchaeota/classificação , Euryarchaeota/isolamento & purificação , Sedimentos Geológicos/química , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Consórcios Microbianos/genética , Proteobactérias/classificação , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase em Tempo Real , Recursos Hídricos
12.
Int J Biochem Cell Biol ; 80: 173-178, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27720933

RESUMO

Secondary metastases are the leading cause of mortality in patients with breast cancer. Cytochrome P450 (CYP) 2J2 (CYP2J2) is upregulated in many human tumors and generates epoxyeicosanoids from arachidonic acid that promote tumorigenesis and metastasis, but at present there is little information on the genes that mediate these actions. In this study MDA-MB-468 breast cancer cells were stably transfected with CYP2J2 (MDA-2J2 cells) and Affymetrix microarray profiling was undertaken. We identified 182 genes that were differentially expressed in MDA-2J2 cells relative to control (MDA-CTL) cells (log[fold of control] ≥2). From gene ontology pathway analysis bone morphogenetic protein (BMP) receptor 1B (BMPR1B) emerged as an important upregulated gene in MDA-2J2 cells. Addition of the BMPR1B ligand BMP2 stimulated the migration of MDA-2J2 cells, but not MDA-CTL cells, from 3D-matrigel droplets. Migration of MDA-2J2 cells was prevented by the BMPR antagonist dorsomorphin. These findings indicate that over-expression of CYP2J2 in MDA-MB-468-derived breast cancer cells activates BMPR1B expression that may contribute to increased migration. Targeting BMPR1B may be a novel approach to inhibit the metastatic activity of breast cancers that contain high levels of CYP2J2.


Assuntos
Receptores de Proteínas Morfogenéticas Ósseas Tipo I/genética , Movimento Celular/genética , Sistema Enzimático do Citocromo P-450/genética , Ativação Transcricional , Neoplasias de Mama Triplo Negativas/patologia , Carcinogênese/genética , Linhagem Celular Tumoral , Expressão Gênica , Ontologia Genética , Humanos , Metástase Neoplásica , Regulação para Cima/genética
13.
Biomed Mater ; 11(3): 035018, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-27305523

RESUMO

Bioceramics for regenerative medicine applications should have the ability to promote adhesion, proliferation and differentiation of osteoblast and osteoclast cells. Osteogenic properties of the material are essential for rapid bone regeneration and new bone formation. The aim of this study was to develop a silicate-based ceramic, gehlenite (GLN, Ca2Al2SiO7), and characterise its physiochemical, biocompatibility and osteogenic properties. A pure GLN powder was synthesised by a facile reactive sintering method and compacted to disc-shaped specimens. The sintering behaviour and degradation of the GLN discs in various buffer solutions were fully characterised. The cytotoxicity of GLN was evaluated by direct and indirect methods. In the indirect method, primary human osteoblast cells (HOBs) were exposed to diluted extracts (100, 50, 25, 12.5 and 6.25 mg ml(-1)) of fine GLN particles in culture medium. The results showed that the extracts did not cause any cytotoxic effect on the HOBs with the number of cells increasing significantly from day 1 to day 7. GLN-supported HOB attachment and proliferation, and significantly enhanced osteogenic gene expression levels (Runx2, osteocalcin, osteopontin and bone sialoprotein) were compared with biphasic calcium phosphate groups (BCP, a mixture of hydroxyapatite (60wt.%) and ß-tricalcium phosphate(40wt.%)). We also demonstrated that in addition to supporting HOB attachment and proliferation, GLN promoted the formation of tartrate-acid resistance phosphatase (TRAP) positive multinucleated osteoclastic cells (OCs) derived from mouse bone marrow cells. Results also demonstrated the ability of GLN to support the polarisation of OCs, a prerequisite for their functional resorptive activity which is mainly influenced by the composition and degradability of biomaterials. Overall, the developed GLN is a prospective candidate to be used in bone regeneration applications due its effective osteogenic properties and biocompatibility.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/fisiologia , Cerâmica/química , Osteoblastos/metabolismo , Osteoclastos/metabolismo , Animais , Materiais Biocompatíveis/química , Células da Medula Óssea/citologia , Osso e Ossos/fisiopatologia , Diferenciação Celular , Proliferação de Células , Meios de Cultura , Fêmur/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Osteogênese , Pós , Regeneração , Estresse Mecânico , Tíbia/metabolismo , Difração de Raios X
14.
J Mech Behav Biomed Mater ; 62: 433-445, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27281161

RESUMO

The most common methods for attaching a device to the internal tissues of the human body are via sutures, clips or staples. These attachment techniques require penetration and manipulation of the tissue. Tears and leaks can often be a complication post-attachment, and scarring usually occurs around the attachment sites. To resolve these issues, it is proposed to develop a soft tissue scaffold impregnated with Rose Bengal/Chitosan solution (RBC-scaffold, 0.01% w/v Rose Bengal, 1.7% w/v Medium Molecular Weight Chitosan). This scaffold will initially attach to the tissue via a light activation method. The light activates the dye in the scaffold which causes cross-links to form between the scaffold and tissue, thus adhering them together. This is done without mechanically manipulating the surrounding tissue, thus avoiding the issues associated with current techniques. Eventually, the scaffold will be resorbed and tissue will integrate for long-term attachment. A variety of tests were performed to characterise the RBC-scaffold. Porosity, interconnectivity, and mechanical strength were measured. Light activation was performed with a broad spectrum (380-780nm) 10W LED lamp exposed to various time lengths (2-15min, Fluence range 0.4-3J/cm(2) ). Adhesive strength of the light-activated bond was measured with lap-shear tests performed on porcine stomach tissue. Cell culture viability was also assessed to confirm tissue integration potential. These properties were compared to Variotis™, an aliphatic polyester soft tissue scaffold which has proven to be viable for soft tissue regeneration. The RBC-scaffolds were found to have high porosity (86.46±2.95%) and connectivity, showing rapid fluid movement. The elastic modulus of the RBC-scaffolds (3.55±1.28MPa) was found to be significantly higher than the controls (0.15±0.058MPa, p<0.01) and approached reported values for human gastrointestinal tissue (2.3MPa). The maximum adhesion strength achieved of the RBC-scaffolds was 8.61±2.81kPa after 15min of light activation, this is comparable to the adhesion strength of fibrin glue on scaffolds. Cell attachment was seen to be similar to the controls, but cells appeared to have better cell survivability. In conclusion, the RBC-scaffolds show promise for use as a novel light activated attachment device with potential applications in attaching an anti-reflux valve in the lower oesophagus and also in wound healing applications for stomach ulcers.


Assuntos
Adesivos , Luz , Tecidos Suporte , Animais , Quitosana/química , Humanos , Teste de Materiais , Poliésteres , Porosidade , Rosa Bengala/química , Estômago/fisiologia , Suínos , Engenharia Tecidual
15.
Huan Jing Ke Xue ; 37(8): 3017-3025, 2016 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-29964727

RESUMO

Dissolved organic matter (DOM) in aquatic ecosystems has gained wide concern because of its influence on the light attenuation, nutrient availability and contaminant transport. Human activities strongly influence the DOM of rivers in different ways, including increased agricultural activities and industrial and domestic emissions. However, recent socio-economic development with rapid urban development has significantly enhanced the discharge of sewage, and has caused high loads of DOM, which in turn pose a great risk to aquatic ecosystems. To effectively guide water management for protecting aquatic ecosystem health, it is very critical to investigate the distribution and source of dissolved organic matter in urban rivers. In this study, the distribution and source analysis of DOM in Beiyun River were evaluated, where covers the most populated area with a population of 14 million, representing the most urbanized watershed of Beijing. Since the main receiving source of the river is treated and untreated wastewater in Beijing City, the water quality is highly polluted by anthropogenic inputs. However, information on DOM of Beiyun river has not been reported. Therefore, this study can not only reveal the biogeochemistry of DOM in Beiyu River, but also provide useful implications of pollution control for similar urban rivers. The fingerprint features were extracted from the Excitation-Emission Matrix Spectrum of fluorescent dissolved organic matter (FDOM) in 23 sampling sites of Beiyun river during November 2013. Three separate fluorescent components were identified by Parallel factor analysis (PARAFAC) model, including two humic-like components (C1: 240, 300/385 nm; C2: 255, 350/400 nm) and one protein-like component (C3: 230, 280/340 nm). The results indicated that humic-like materials were generally the dominated component of FDOM, accounting for 76.18% of the average total fluorescence intensity. Positive relationships were found between the fluorescence intensity and the concentrations of some water quality indicators, such as total nitrogen, ammonia nitrogen and total phosphorus, indicating the same sources of these components. Thus, the migration and transformation of nitrogen & phosphorus could also influence the level of FDOM. The distribution of total fluorescence intensity showed a distinctly different spatial pattern. The fluorescence intensity decreased firstly along the upstream to midstream continuum, and then increased from the midstream to downstream. The FDOM in the upstream could be attributed to the industrial effluent and agricultural runoff inputs. Among the upstream to downstream continuum, the content of FDOM in the midstream was the lowest. Limited domestic pollution was suggested as the major source. In the downstream, the sources of FDOM could be interpreted as industrial, agricultural wastewater and livestock wastewater discharge. The relative abundance of protein-like materials was markedly increased in this area, indicating the sources of DOM was highly impacted by human activities. In addition, our study also concluded that the removal efficiency of DOM in wastewater plants is not very desirable, which implied that stronger support for DOM removal in sewage system is needed to alleviate DOM pollution and improve water quality.

16.
PLoS One ; 10(1): e0113426, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25602473

RESUMO

Zirconium (Zr) is an element commonly used in dental and orthopedic implants either as zirconia (ZrO2) or in metal alloys. It can also be incorporated into calcium silicate-based ceramics. However, the effects of in vitro culture of human osteoblasts (HOBs) with soluble ionic forms of Zr have not been determined. In this study, primary culture of human osteoblasts was conducted in the presence of medium containing either ZrCl4 or Zirconium (IV) oxynitrate (ZrO(NO3)2) at concentrations of 0, 5, 50 and 500 µM, and osteoblast proliferation, differentiation and calcium deposition were assessed. Incubation of human osteoblast cultures with Zr ions increased the proliferation of human osteoblasts and also gene expression of genetic markers of osteoblast differentiation. In 21 and 28 day cultures, Zr ions at concentrations of 50 and 500 µM increased the deposition of calcium phosphate. In addition, the gene expression of BMP2 and BMP receptors was increased in response to culture with Zr ions and this was associated with increased phosphorylation of SMAD1/5. Moreover, Noggin suppressed osteogenic gene expression in HOBs co-treated with Zr ions. In conclusion, Zr ions appear able to induce both the proliferation and the differentiation of primary human osteoblasts. This is associated with up-regulation of BMP2 expression and activation of BMP signaling suggesting this action is, at least in part, mediated by BMP signaling.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Cloretos/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Smad/metabolismo , Zircônio/farmacologia , Proteína Morfogenética Óssea 2/genética , Receptores de Proteínas Morfogenéticas Ósseas/genética , Calcificação Fisiológica/efeitos dos fármacos , Proteínas de Transporte/metabolismo , Diferenciação Celular , Proliferação de Células/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Marcadores Genéticos , Humanos , Osteoblastos/citologia , Osteogênese/genética
17.
Carbohydr Polym ; 115: 146-51, 2015 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-25439879

RESUMO

Catalytic hydrolysis of biomass over solid catalysts can be one of the most efficient pathways for a future sustainable society dependent on cellulose biomass. In this work metal-organic framework MIL-53(Al) without any functionalization was directly employed as an efficient heterogeneous catalyst for the hydrolysis of carboxymethyl cellulose (CMC) to 5-hydroxymethyl-furaldehyde (5-HMF) in aqueous phase. A 5-HMF molar yield of 40.3% and total reducing sugar (TRS) molar yield of 54.2% were obtained with water as single solvent at 473 K for 4 h. The catalyst could be reused three times without losing activity to a greater extent. With the remarkable advantages such as the use of water as single solvent and MIL-53(Al) as a novel heterogeneous green catalyst, the work provides a new platform for the production of value added chemicals and liquid fuels from biomass.


Assuntos
Alumínio/química , Carboximetilcelulose Sódica/química , Furaldeído/análogos & derivados , Compostos Organometálicos/química , Temperatura Ambiente , Catálise , Furaldeído/síntese química , Furaldeído/química , Hidrólise
18.
J Environ Sci (China) ; 26(5): 1195-202, 2014 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25079651

RESUMO

Cyanobacteria, which occurred in eutrophic water harvest solar light to carry out photosynthesis with high efficiency. In this work, cyanobacteria (Microcystis sp.) were used as biotemplate to synthesize titania structure. The synthesized titania sample had similar morphology to that of the original template in spite of the fragile unicellular structures and extremely high water content of cyanobacterial cells. Incorporation of biogenic C, as well as the morphology inherited from biotemplate improved visible-light absorbance of the titania structure. The sample exhibited higher visible-light photocatalytic activity than commercial titania photocatalyst Degussa P25 for Rhodamine B (RhB) degradation. Compared with those C-doped titania photocatalysts prepared by other methods, cyanobacteria templated titania photocatalyst offer some potential for competitive advantages. The reported strategy opened up a new use for the cyanobacteria. It could also be used for titania in applications such as treatment of polluted water, dye-sensitized solar cells, or other regions.


Assuntos
Cianobactérias/metabolismo , Corantes Fluorescentes/química , Luz , Rodaminas/química , Titânio/química , Poluentes Químicos da Água/química , Cianobactérias/química , Processos Fotoquímicos
19.
Chem Commun (Camb) ; 50(53): 7063-6, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-24848342

RESUMO

A stable photoactive metal-organic framework UiO-66(Zr) sensitized by adsorbed or directly added rhodamine B dye exhibited photocatalytic activity for hydrogen evolution under visible-light illumination (λ≥ 420 nm). Using Pt as a co-catalyst, the adsorbed and directly added dye extremely enhanced the photocatalytic activity to 30 and 26 times the value afforded by bare Pt@UiO-66(Zr), respectively.

20.
Beilstein J Nanotechnol ; 4: 949-55, 2013 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-24455453

RESUMO

In this study, NiS/ZnIn2S4 nanocomposites were successfully prepared via a facile two-step hydrothermal process. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Their photocatalytic performance for hydrogen evolution under visible light irradiation was also investigated. It was found that the photocatalytic hydrogen evolution activity over hexagonal ZnIn2S4 can be significantly increased by loading NiS as a co-catalyst. The formation of a good junction between ZnIn2S4 and NiS via the two step hydrothermal processes is beneficial for the directional migration of the photo-excited electrons from ZnIn2S4 to NiS. The highest photocatalytic hydrogen evolution rate (104.7 µmol/h), which is even higher than that over Pt/ZnIn2S4 nanocomposite (77.8 µmol/h), was observed over an optimum NiS loading amount of 0.5 wt %. This work demonstrates a high potential of the developing of environmental friendly, cheap noble-metal-free co-catalyst for semiconductor-based photocatalytic hydrogen evolution.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA