573 results on '"Barbosa, Mário A."'
Search Results
202. Selective protein adsorption modulates platelet adhesion and activation to oligo(ethylene glycol)‐terminated self‐assembled monolayers with C18 ligands
- Author
-
Gonçalves, Inês C., primary, Martins, M. Cristina L., additional, Barbosa, Mário A., additional, Naeemi, Esmaeel, additional, and Ratner, Buddy D., additional
- Published
- 2008
- Full Text
- View/download PDF
203. Injectability of a bone filler system based on hydroxyapatite microspheres and a vehicle with in situ gel‐forming ability
- Author
-
Oliveira, Serafim M., primary, Barrias, Cristina C., additional, Almeida, Isabel F., additional, Costa, Paulo C., additional, Ferreira, Maria R. Pena, additional, Bahia, Maria F., additional, and Barbosa, Mário A., additional
- Published
- 2008
- Full Text
- View/download PDF
204. Introdução à Romanza senza parole "T'Amo" (versão para quarteto duplo de cordas), de Meneleu Campos.
- Author
-
Dantas Barbosa, Mário Alexandre and Volpe, Maria Alice
- Abstract
This article presents the musicological edition of work entitled "T'Amo!" Romanza Senza Parole (per Quartetto [Quintetto] d'archi (doppio), by the Pará State composer Otávio Meneleu Campos (1872-1927), on an arrangement made during his tour to the Southern of his country in 1909. The edition was based on the autograph manuscripts of the score and parts held by the National Library (Rio de Janeiro, Brazil)'s Music and Sound Collection Division. [ABSTRACT FROM AUTHOR]
- Published
- 2015
205. The influence of functional groups of self‐assembled monolayers on fibrous capsule formation and cell recruitment
- Author
-
Barbosa, Judite N., primary, Madureira, Pedro, additional, Barbosa, Mário A., additional, and Águas, Artur P., additional
- Published
- 2005
- Full Text
- View/download PDF
206. The attraction of Mac-1+ phagocytes during acute inflammation by methyl-coated self-assembled monolayers
- Author
-
Barbosa, Judite N., primary, Madureira, Pedro, additional, Barbosa, Mário A., additional, and Águas, Artur P., additional
- Published
- 2005
- Full Text
- View/download PDF
207. Adsorption of a therapeutic enzyme to self-assembled monolayers: effect of surface chemistry and solution pH on the amount and activity of adsorbed enzyme
- Author
-
Barrias, Cristina C., primary, Martins, Ma Cristina L., additional, Miranda, Ma Clara Sá, additional, and Barbosa, Mário A., additional
- Published
- 2005
- Full Text
- View/download PDF
208. Inflammatory cell recruitment and adhesion to methyl‐terminated self‐assembled monolayers: Effect of implantation time
- Author
-
Barbosa, Judite N., primary, Barbosa, Mário A., additional, and Águas, Artur P., additional
- Published
- 2005
- Full Text
- View/download PDF
209. Proliferation, activity, and osteogenic differentiation of bone marrow stromal cells cultured on calcium titanium phosphate microspheres
- Author
-
Barrias, Cristina C., primary, Ribeiro, Cristina C., additional, Lamghari, Meriem, additional, Miranda, Clara Sá, additional, and Barbosa, Mário A., additional
- Published
- 2004
- Full Text
- View/download PDF
210. Inflammatory responses and cell adhesion to self-assembled monolayers of alkanethiolates on gold
- Author
-
Barbosa, Judite N., primary, Barbosa, Mário A., additional, and Águas, Artur P., additional
- Published
- 2004
- Full Text
- View/download PDF
211. Protein Adsorption Characterization.
- Author
-
Martins, M. Cristina L., Sousa, Susana R., Antunes, Joana C., and Barbosa, Mário A.
- Published
- 2012
- Full Text
- View/download PDF
212. Adhesion of human leukocytes to biomaterials: An in vitro study using alkanethiolate monolayers with different chemically functionalized surfaces
- Author
-
Barbosa, Judite N., primary, Barbosa, Mário A., additional, and Águas, Artur P., additional
- Published
- 2003
- Full Text
- View/download PDF
213. A Degenerative/Proinflammatory Intervertebral Disc Organ Culture: An Ex VivoModel for Anti-inflammatory Drug and Cell Therapy
- Author
-
Teixeira, Graciosa Q., Boldt, Antje, Nagl, Ines, Pereira, Catarina Leite, Benz, Karin, Wilke, Hans-Joachim, Ignatius, Anita, Barbosa, Mário A., Gonçalves, Raquel M., and Neidlinger-Wilke, Cornelia
- Abstract
Resolution of intervertebral disc (IVD) degeneration-associated inflammation is a prerequisite for tissue regeneration and could possibly be achieved by strategies ranging from pharmacological to cell-based therapies. In this study, a proinflammatory disc organ culture model was established. Bovine caudal disc punches were needle punctured and additionally stimulated with lipopolysaccharide (10 μg/mL) or interleukin-1β (IL-1β, 10–100 ng/mL) for 48 h. Two intradiscal therapeutic approaches were tested: (i) a nonsteroidal anti-inflammatory drug, diclofenac (Df) and (ii) human mesenchymal stem/stromal cells (MSCs) embedded in an albumin/hyaluronan hydrogel. IL-1β-treated disc organ cultures showed a statistically significant upregulation of proinflammatory markers (IL-6, IL-8, prostaglandin E2[PGE2]) and metalloproteases (MMP1, MMP3) expression, while extracellular matrix (ECM) proteins (collagen II, aggrecan) were significantly downregulated. The injection of the anti-inflammatory drug, Df, was able to reduce the levels of proinflammatory cytokines and MMPs and surprisingly increase ECM protein levels. These results point the intradiscal application of anti-inflammatory drugs as promising therapeutics for disc degeneration. In parallel, the immunomodulatory role of MSCs on this model was also evaluated. Although a slight downregulation of IL-6and IL-8expression could be found, the variability among the five donors tested was high, suggesting that the beneficial effect of these cells on disc degeneration needs to be further evaluated. The proinflammatory/degenerative IVD organ culture model established can be considered a suitable approach for testing novel therapeutic drugs, thus reducing the number of animals in in vivoexperimentation. Moreover, this model can be used to address the cellular and molecular mechanisms that regulate inflammation in the IVD and their implications in tissue degeneration.
- Published
- 2016
- Full Text
- View/download PDF
214. Ação promotora do berílio em catalisadores da síntese do estireno
- Author
-
Barbosa, Mário Nilo Mendes, primary, Carvalho, Marly Fernandes Araújo de, additional, and Rangel, Maria do Carmo, additional
- Published
- 1997
- Full Text
- View/download PDF
215. Kinetics and isotherm of fibronectin adsorption to three-dimensional porous chitosan scaffolds explored by 125I-radiolabelling.
- Author
-
Amaral, Isabel F., Sousa, Susana R., Neiva, Ismael, Marcos-Silva, Lara, Kirkpatrick, Charles J., Barbosa, Mário A., and Pêgo, Ana P.
- Subjects
FIBRONECTINS ,ACETYLATION ,CHITOSAN ,TISSUE scaffolds ,IMMUNOFLUORESCENCE ,CELL adhesion - Abstract
In this study,
125 I-radiolabelling was explored to follow the kinetics and isotherm of fibronectin (FN) adsorption to porous polymeric scaffolds, as well as to assess the elution and exchangeability of pre-adsorbed FN following incubation in serum-containing culture medium. Chitosan (CH) porous scaffolds with two different degrees of acetylation (DA 4% and 15%) were incubated in FN solutions with concentrations ranging from 5 to 50 μg/mL. the kinetic and isotherm of FN adsorption to CH were successfully followed using125 I-FN as a tracer molecule. While on DA 4% the levels of adsorbed FN increased linearly with FN solution concentration, on DA 15% a saturation plateau was attained, and FN adsorbed amounts were significantly lower. these findings were supported by immunofluorescent studies that revealed, for the same FN solution concentration, higher levels of exposed cell-binding domains on DA 4% as compared with DA 15%. Following incubation in serum containing medium, DA 4% also revealed higher ability to exchange pre-adsorbed FN by new FN molecules from serum than DA 15%. In accordance, when assessing the efficacy of passively adsorbed FN to promote endothelial cell (EC) adhesion to CH, ECS were found to adhere at higher levels to DA 4% as compared with DA 15%, 5 μg/mL of FN being already efficient in promoting cell adhesion and cytoskeletal organization on CH with DA 4%. taken together the results show that protein radiolabelling can be used as an effective tool to study protein adsorption to porous polymeric scaffolds, both from single and complex protein solutions. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
216. Low-Power GaAlAs Laser Irradiation Promotes the Proliferation and Osteogenic Differentiation of Stem Cells via IGF1 and BMP2.
- Author
-
Jyun-Yi Wu, Yan-Hsiung Wang, Gwo-Jaw Wang, Mei-Ling Ho, Chau-Zen Wang, Ming-Long Yeh, Chia-Hsin Chen, and Barbosa, Mário A.
- Subjects
GALLIUM aluminum arsenide ,IRRADIATION ,FRACTURE fixation ,BONE marrow ,MESENCHYMAL stem cells ,LACTATE dehydrogenase - Abstract
Low-power laser irradiation (LPLI) has been found to induce various biological effects and cellular processes. Also, LPLI has been shown to promote fracture repair. Until now, it has been unclear how LPLI promotes bone formation and fracture healing. The aim of this study was to investigate the potential mechanism of LPLI-mediated enhancement of bone formation using mouse bone marrow mesenchymal stem cells (D1 cells). D1 cells were irradiated daily with a galliumaluminum- arsenide (GaAlAs) laser at dose of 0, 1, 2, or 4 J/cm². The lactate dehydrogenase (LDH) assay showed no cytotoxic effects of LPLI on D1 cells, and instead, LPLI at 4 J/cm² significantly promoted D1 cell proliferation. LPLI also enhanced osteogenic differentiation in a dose-dependent manner and moderately increased expression of osteogenic markers. The neutralization experiments indicated that LPLI regulated insulin-like growth factor 1 (IGF1) and bone morphogenetic protein 2 (BMP2) signaling to promote cell proliferation and/or osteogenic differentiation. In conclusion, our study suggests that LPLI may induce IGF1 expression to promote both the proliferation and osteogenic differentiation of D1 cells, whereas it may induce BMP2 expression primarily to enhance osteogenic differentiation. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
217. Immobilization of Lipases on Alkyl Silane Modified Magnetic Nanoparticles: Effect of Alkyl Chain Length on Enzyme Activity.
- Author
-
Jiqian Wang, Gang Meng, Kai Tao, Min Feng, Xiubo Zhao, Zhen Li, Hai Xu, Daohong Xia, Lu, Jian R., and Barbosa, Mário A.
- Subjects
WASTE recycling ,ENZYMES ,SEWAGE disposal ,IMMOBILIZATION stress ,LIPASES ,NANOPARTICLES ,HYDROPHOBIC compounds - Abstract
Background: Biocatalytic processes often require a full recycling of biocatalysts to optimize economic benefits and minimize waste disposal. Immobilization of biocatalysts onto particulate carriers has been widely explored as an option to meet these requirements. However, surface properties often affect the amount of biocatalysts immobilized, their bioactivity and stability, hampering their wide applications. The aim of this work is to explore how immobilization of lipases onto magnetite nanoparticles affects their biocatalytic performance under carefully controlled surface modification. Methodology/Principal Findings: Magnetite nanoparticles, prepared through a co- precipitation method, were coated with alkyl silanes of different alkyl chain lengths to modulate their surface hydrophobicity. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through hydrophobic interaction. Enzyme activity was assessed by catalytic hydrolysis of p- nitrophenyl acetate. The activity of immobilized lipases was found to increase with increasing chain length of the alkyl silane. Furthermore, the catalytic activities of lipases immobilized on trimethoxyl octadecyl silane (C18) modified Fe
3 O4 were a factor of 2 or more than the values reported from other surface immobilized systems. After 7 recycles, the activities of the lipases immobilized on C18 modified nanoparticles retained 65%, indicating significant enhancement of stability as well through hydrophobic interaction. Lipase immobilized magnetic nanoparticles facilitated easy separation and recycling with high activity retaining. Conclusions/Significance: The activity of immobilized lipases increased with increasing alkyl chain length of the alkyl trimethoxy silanes used in the surface modification of magnetite nanoparticles. Lipase stability was also improved through hydrophobic interaction. Alkyl silane modified magnetite nanoparticles are thus highly attractive carriers for enzyme immobilization enabling efficient enzyme recovery and recycling. [ABSTRACT FROM AUTHOR]- Published
- 2012
- Full Text
- View/download PDF
218. Icaritin, an Exogenous Phytomolecule, Enhances Osteogenesis but Not Angiogenesis--An In Vitro Efficacy Study.
- Author
-
Dong Yao, Xin-Hui Xie, Xin-Luan Wang, Chao Wan, Yuk-Wai Lee, Shi-Hui Chen, Duan-Qing Pei, Yi-Xiang Wang, Gang Li, Ling Qin, and Barbosa, Mário A.
- Subjects
FLAVONOIDS ,STEM cells ,CELL proliferation ,CELL migration ,UMBILICAL veins ,ENDOTHELIAL cells - Abstract
We found that Icaritin, an intestinal metabolite of Epimedium-derived flavonoids (EF) enhanced osteoblastic differentiation of mesenchymal stem cells (MSCs) only under osteogenic induction conditions. We also demonstrated its effect on inhibition of adipogenic differentiation of MSCs. Unlike the findings of others on EF compounds, we showed that Icaritin was unable to promote proliferation, migration and tube like structure formation by human umbilical vein endothelial cells (HUVECs) in vitro. These results suggested that the exogenous phytomolecule Icaritin possessed the potential for enhancing bone formation via its osteopromotive but not an osteoinductive mechanism. Though some flavonoids were shown to regulate the coupling process of angiogenesis and osteogenesis during bone repair, our results suggested that Icaritin did not have direct effect on enhancing angiogenesis in vitro. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
219. Música religiosa e para as festividades das igrejas em Belém do Pará no final do século XIX.
- Author
-
Dantas Barbosa, Mário Alexandre
- Subjects
- *
SACRED music , *MUSIC , *MUSICIANS , *CATHOLIC liturgy , *FESTIVALS , *MUSIC history - Abstract
This article presents an overview of sacred music in Belém do Pará in the late 19th century, and also focuses in the sacred works of the Pará composer Otávio Meneleu Campos (1872-1927), a musician that acted in his hometown during the first quarter of 20th century. The first section of the article, a product of a detailed survey in the newspaper A Provincia do Pará, shows some important details about the main musicians devoted to provide music for liturgical services and popular festivals sponsored by Catholic Church. The referred survey has the second semester of 1899 as its time delimitation, when Meneleu Campos was about to return to his hometown after spending almost ten years in his studies abroad. The second part, reached through an intersection of information colected from the musical manuscripts and other sources (periodicals and specific bibliography about the composer) addresses the compositional context of Meneleu Campos' sacred works and presents a balance of this parcel in contrast to his global production. [ABSTRACT FROM AUTHOR]
- Published
- 2012
220. Biosynthesis of highly pure poly-γ-glutamic acid for biomedical applications.
- Author
-
Pereira, Catarina, Antunes, Joana, Gonçalves, Raquel, Ferreira-da-Silva, Frederico, and Barbosa, Mário
- Subjects
BIOSYNTHESIS ,GLUTAMIC acid ,BIOCOMPATIBILITY ,BIOMEDICAL engineering ,BIOMATERIALS ,EXCITATORY amino acids - Abstract
The remarkable properties of poly-aminoacids, mainly their biocompatibility and biodegradability, have prompted an increasing interest in these polymers for biomedical applications. Poly-γ-glutamic acid (γ-PGA) is one of the most interesting poly-aminoacids with potential applications as a biomaterial. Here we describe the production and characterization of γ-PGA by Bacillus subtilis natto. The γ-PGA was produced with low molecular weight (10-50 kDa), high purity grade (>99 %) and a d-/ l-glutamate ratio of 50-60/50-40 %. To evaluate the feasibility of using this γ-PGA as a biomaterial, chitosan (Ch)/γ-PGA nanoparticles were prepared by the coacervation method at pH ranging from 3.0 to 5.0, with dimensions in the interval 214-221 nm with a poly-dispersion index of ca. 0.2. The high purity of γ-PGA produced by this method, which is firstly described here, renders this biopolymer suitable for biomedical applications. Moreover, the Ch/γ-PGA nanocomplexes developed in this investigation can be combined with biologically active substances for their delivery in the organism. The fact that the assembly between Ch and γ-PGA relies on electrostatic interactions enables addition of other molecules that can be released into the medium through changes from acidic to physiological pH, without loss in biological activity. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
221. Phenotypic and proliferative modulation of human mesenchymal stem cells via crosstalk with endothelial cells.
- Author
-
Bidarra, Sílvia J., Barrias, Cristina C., Barbosa, Mário A., Soares, Raquel, Amédée, Joelle, and Granja, Pedro L.
- Subjects
MESENCHYMAL stem cells ,CELL proliferation ,CELL culture ,FLOW cytometry ,PHENOTYPES ,TISSUE engineering - Abstract
Abstract: The purpose of this work was to investigate if a coculture system of human mesenchymal stem cells (hMSC) with endothelial cells (human umbilical vein endothelial cells, HUVEC) could modulate the phenotype and proliferation of harvested MSCs. In addition to previous investigations on the crosstalk between these two cell types, in the present work different relative cell ratios were analyzed for long, therapeutically relevant, culture periods. Moreover, MSCs osteogenic commitment was assessed in a non-osteogenic medium and in the presence of HUVECs through magnetic cell separation, cell quantification by flow cytometry, morphology by fluorescent microscopy, metabolic activity and gene expression of osteogenic markers. Collectively, the present findings demonstrate that, by coculturing MSCs with HUVECs, there was not only the promotion of osteogenic differentiation (and its enhancement, depending on the relative cell ratios used), but also a significant increase on MSCs proliferation. This augmentation in cell proliferation occurred independently of relative cell ratios, but was favored by higher relative amounts of HUVECs. Taken together, this data suggests that HUVECs not only modulate MSC phenotype but also their proliferation rate. Therefore, a coculture system of MSCs and HUVECs can a have a broad impact on bone tissue engineering approaches. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
222. Platelet and leukocyte adhesion to albumin binding self-assembled monolayers.
- Author
-
Gonçalves, Inês C., Martins, M. Cristina L., Barbosa, Judite N., Oliveira, Pedro, Barbosa, Mário A., and Ratner, Buddy D.
- Subjects
ALBUMINS ,PROTEIN binding ,BLOOD platelets ,LEUCOCYTES ,ADSORPTION (Chemistry) ,MONOMOLECULAR films - Abstract
This study reports the use of tetraethylene glycol-terminated self-assembled monolayers (EG SAMs) as a background non-fouling surface to study the effect of an 18 carbon ligand (C18) on albumin selective and reversible adsorption and subsequent platelet and leukocyte adhesion. Surface characterization techniques revealed an efficient immobilization of different levels of C18 ligand on EG SAMs and an increase of surface thickness and hydrophobicity with the increase of C18 ligands. Albumin adsorption increased as the percentage of C18 ligands on the surface increased, but only 2.5%C18 SAMs adsorbed albumin in a selective and reversible way. Adherent platelets also increased with the amount of immobilized C18. Pre-immersion of samples in albumin before contact with platelets demonstrated an 80% decrease in platelet adhesion. Pre-immersion in plasma was only relevant for 2.5%C18 SAMs since this was the only surface to have less platelet adhesion compared to buffer pre-immersion. EG SAMs adhered negligible amounts of leukocytes, but surfaces with C18 ligands have some adherent leukocytes. Except for 10%C18 SAMs, which increased leukocyte adhesion after albumin pre-adhesion, protein pre-immersion did not influence leukocyte adhesion. It has been shown that a surface with a specific surface concentration of albumin-binding ligands (2.5%C18 SAMs) can recruit albumin selectively and reversibly and minimize the adhesion of platelets, despite still adhering some leukocytes. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
223. Interactions of leukocytes and platelets with poly(lysine/leucine) immobilized on tetraethylene glycol-terminated self-assembled monolayers.
- Author
-
Martins, M. Cristina L., Ochoa-Mendes, Vanessa, Ferreira, Gisela, Barbosa, Judite N., Curtin, Scott A., Ratner, Buddy D., and Barbosa, Mário A.
- Subjects
LEUCOCYTES ,BLOOD platelets ,LYSINE ,ETHYLENE glycol ,MOLECULAR self-assembly ,CELL adhesion ,HEPARIN ,MONOMOLECULAR films - Abstract
Abstract: Surfaces that bind heparin are important for biomaterials for blood deheparinization. In our recent work it was demonstrated that a polypeptide composed of l-lysine and l-leucine (pKL), after immobilization onto tetra(ethylene glycol) terminated self-assembled monolayers (EG4-SAMs), can bind heparin from blood plasma in a selective, concentration-dependent way. During this work the effect of this peptide on platelet adhesion and activation and leukocyte adhesion was studied. The surface charge of these nanostructured surfaces was evaluated in order to correlate the effect of positively charged amine groups and hydrophobic methyl groups on the behavior of platelets and leukocyte adhesion. The results demonstrated that the presence of pKL decreased leukocyte adhesion to EG4-SAMs at all concentrations used. This effect is even more pronounced when surfaces were pre-immersed in heparinized plasma. In contrast, there is an increase in platelet adhesion and activation with increased percentage immobilized pKL. This effect is enhanced when surfaces were pre-immersed in heparinized plasma. However, adsorbed pKL in very low amounts does not induce platelet adhesion and activation compared with EG4, even when pre-immersed in plasma. Since only low pKL amounts are necessary to induce heparin selectivity, these results are promising for the development of heparin-binding biomaterials for blood deheparinization. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
224. Characterization of Polymeric Solutions as Injectable Vehicles for Hydroxyapatite Microspheres.
- Author
-
Oliveira, Serafim, Almeida, Isabel, Costa, Paulo, Barrias, Cristina, Ferreira, M., Bahia, M., and Barbosa, Mário
- Abstract
A polymeric solution and a reinforcement phase can work as an injectable material to fill up bone defects. However, the properties of the solution should be suitable to enable the transport of that extra phase. Additionally, the use of biocompatible materials is a requirement for tissue regeneration. Thus, we intended to optimize a biocompatible polymeric solution able to carry hydroxyapatite microspheres into bone defects using an orthopedic injectable device. To achieve that goal, polymers usually regarded as biocompatible were selected, namely sodium carboxymethylcellulose, hydroxypropylmethylcellulose, and Na-alginate (ALG). The rheological properties of the polymeric solutions at different concentrations were assessed by viscosimetry before and after moist heat sterilization. In order to correlate rheological properties with injectability, solutions were tested using an orthopedic device applied for minimal invasive surgeries. Among the three polymers, ALG solutions presented the most suitable properties for our goal and a non-sterile ALG 6% solution was successfully used to perform preliminary injection tests of hydroxyapatite microspheres. Sterile ALG 7.25% solution was found to closely match non-sterile ALG 6% properties and it was selected as the optimal vehicle. Finally, sterile ALG 7.25% physical stability was studied at different temperatures over a 3-month period. It was observed that its rheological properties presented minor changes when stored at 25°C or at 4°C. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
225. The effect of immobilization of thrombin inhibitors onto self-assembled monolayers on the adsorption and activity of thrombin
- Author
-
Freitas, Sidónio C., Barbosa, Mário A., and Martins, M. Cristina L.
- Subjects
- *
ANTITHROMBINS , *MOLECULAR self-assembly , *MONOMOLECULAR films , *ADSORPTION (Chemistry) , *BIOMEDICAL materials , *BIOCOMPATIBILITY , *BLOOD coagulation , *IMMOBILIZED proteins - Abstract
Abstract: Thrombus formation is the major problem associated with biomaterials for blood contact medical devices. The immobilization of inhibitors to thrombin, a serine protease that plays a central role on the coagulation system, on the surface of biomaterials should be a good strategy to avoid blood clotting and increase their hemocompatibility. The aim of this work is the design of a nanostructured surface with capacity to adsorb and inactivate thrombin. The pentapeptide sequence d-Phenylalanine–Proline–Arginine–Proline–Glycine (fPRPG), that was described as a thrombin inhibitor, was immobilized onto tetra(ethylene glycol) terminated self-assembled monolayers (EG4-SAMs). Surface containing different amounts of fPRPG were prepared using different concentrations of N,N′-Carbonyldiimidazole (CDI) during immobilization. The efficiency of fPRPG immobilization was followed using ellipsometry, contact angle measurements, Infrared reflection absorption spectroscopy (IRRAS) and X-ray photoelectron spectroscopy (XPS). Thrombin adsorption was quantified using radiolabelled thrombin and its activity in solution and after adsorption on the developed surfaces was assessed using a chromogenic assay. It was found that, although the immobilization of fPRPG on to EG4-SAMs does not increase its selectivity to thrombin, the activity of the adsorbed thrombin was inhibited in a peptide concentration dependent way. We concluded that SAMs with fPRPG immobilized in high amounts can be used as thrombin-inhibitor surfaces, which is a good step on the development of new surfaces for blood contact devices. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
226. Differential effects of eight metal ions on lymphocyte differentiation antigens in vitro
- Author
-
Bravo, Isabel, primary, Carvalho, Graça S., additional, Barbosa, Mário A., additional, and de Sousa, Maria, additional
- Published
- 1990
- Full Text
- View/download PDF
227. Immunomodulatory biomaterial-based wound dressings advance the healing of chronic wounds via regulating macrophage behavior
- Author
-
Sousa, Ana Beatriz, Águas, Artur P, Barbosa, Mário A, and Barbosa, Judite N
- Abstract
Successful wound healing is a process that has three overlying phases: inflammatory, proliferative and remodeling. Chronic wounds are characterized by a perpetuated inflammation that inhibits the proliferative and remodeling phases and impairs the wound healing. Macrophages are key modulators of the wound healing process. Initially, they are responsible for the wound cleaning and for the phagocytosis of pathogens and afterwards they lead to the resolution of the inflammatory response and they express growth factors important for angiogenesis and cytokines and growth factors needed for cell proliferation and deposition of extracellular matrix. The phenotype of the macrophage changes gradually throughout the healing process from the initial M1 pro-inflammatory phenotype characteristic of the acute response to the M2 pro-regenerative phenotype that allows an accurate tissue repair. In chronic wounds, M1 pro-inflammatory macrophages persist and impair tissue repair. As such, immunomodulatory biomaterials arise as promising solutions to accelerate the wound healing process. In this review, we discuss the importance of macrophages and their polarization throughout the different phases of wound healing; macrophage dysfunction in chronic wounds and the use of immunomodulatory biomaterials to overcome the critical problem of chronic wounds—the continued inflammatory phase that impairs healing.
- Published
- 2022
- Full Text
- View/download PDF
228. Enhanced mesenchymal stromal cell recruitment via natural killer cells by incorporation of inflammatory signals in biomaterials
- Author
-
Almeida, Catarina R., Vasconcelos, Daniela P., Gonçalves, Raquel M., and Barbosa, Mário A.
- Abstract
An exacerbated inflammatory response questions biomaterial biocompatibility, but on the other hand, inflammation has a central role in the regulation of tissue regeneration. Therefore, it may be argued that an ‘ideal’ inflammatory response is crucial to achieve efficient tissue repair/regeneration. Natural killer (NK) cells, being one of the first populations arriving at an injury site, can have an important role in regulating bone repair/regeneration, particularly through interactions with mesenchymal stem/stromal cells (MSCs). Here, we studied how biomaterials designed to incorporate inflammatory signals affected NK cell behaviour and NK cell–MSC interactions. Adsorption of the pro-inflammatory molecule fibrinogen (Fg) to chitosan films led to a 1.5-fold increase in adhesion of peripheral blood human NK cells, without an increase in cytokine secretion. Most importantly, it was found that NK cells are capable of stimulating a threefold increase in human bone marrow MSC invasion, a key event taking place in tissue repair, but did not affect the expression of the differentiation marker alkaline phosphatase (ALP). Of significant importance, this NK cell-mediated MSC recruitment was modulated by Fg adsorption. Designing novel biomaterials leading to rational modulation of the inflammatory response is proposed as an alternative to current bone regeneration strategies.
- Published
- 2012
- Full Text
- View/download PDF
229. Engineering Endochondral Bone: In VitroStudies
- Author
-
Oliveira, Serafim M., Amaral, Isabel F., Barbosa, Mário A., and Teixeira, Cristina C.
- Abstract
Chitosan scaffolds have been shown to possess biological and mechanical properties suitable for tissue engineering and clinical applications. In the present work, chitosan sponges were evaluated regarding their ability to support cartilage cell proliferation and maturation, which are the first steps in endochondral bone formation. Chitosan sponges were seeded with chondrocytes isolated from chicken embryo sterna. Chondrocyte/chitosan constructs were cultured for 20 days, and treated with retinoic acid (RA) to induce chondrocyte maturation and matrix synthesis. At different time points, samples were collected for microscopic, histological, biochemical, and mechanical analyses. Results show chondrocyte attachment, proliferation, and abundant matrix synthesis, completely obliterating the pores of the sponges. RA treatment caused chondrocyte hypertrophy, characterized by the presence of type X collagen in the extracellular matrix and increased alkaline phosphatase activity. In addition, hypertrophy markedly changed the mechanical properties of the chondrocyte/chitosan constructs. In conclusion, we have developed chitosan sponges with adequate pore structure and mechanical properties to serve as a support for hypertrophic chondrocytes. In parallel studies, we have evaluated the ability of this mature cartilage scaffold to induce endochondral ossification.
- Published
- 2009
- Full Text
- View/download PDF
230. Albumin adsorption on Cibacron Blue F3G-A immobilized onto oligo(ethylene glycol)-terminated self-assembled monolayers
- Author
-
Martins, Ma, Naeemi, Esmaeel, Ratner, Buddy, and Barbosa, Mário
- Abstract
Self-assembled monolayers can be tailored with specific ligands to a certain protein and at the same time prevent the non-specific adsorption of other proteins. Cibacron Blue F3G-A (CB-thiol) was successfully immobilized onto tetra(ethylene glycol)-terminated alkanethiol (CB-thiol). The affinity of human serum albumin (HSA) to immobilized Cibacron Blue F3G-A was studied using mixed thiolate self-assembled monolayers on gold with different n-alkyl chain lengths and functional terminal groups (CH3-; OH- and tetra(ethylene glycol)). Surfaces were characterized using X-ray photoelectron spectroscopy and water contact angle measurements. Albumin adsorption and exchangeability of the adsorbed albumin molecules with other albumin molecules in solution were evaluated using 125I-radiolabeled HSA. Competitive adsorption between albumin and fibrinogen to the different self-assembled monolayers (SAMs) was also investigated. Results showed that the incorporation of CB-thiol on the monolayers does not increase the HSA adsorption and reversibility on the SAMs. However, although specific adsorption of HSA to the immobilized Cibacron Blue F3G-A was not demonstrated, the presence of CB-thiol decreases the affinity of fibrinogen to the OH-terminated SAMs.
- Published
- 2003
- Full Text
- View/download PDF
231. Comparative effects of nacre watersoluble matrix and dexamethasone on the alkaline phosphatase activity of MRC5 fibroblasts
- Author
-
Almeida, Maria José, Pereira, Lucilia, Milet, Christian, Haigle, Josiane, Barbosa, Mário, and Lopez, Evelyne
- Abstract
In this study we demonstrate, for the first time, that dexamethasone and BMP2 stimulated alkaline phosphatase ALP activity in MRC5 fibroblasts, a cell line derived from human fetal lung. Previously we reported that the watersoluble matrix WSM of nacre obtained from the inner shell layer of the oyster Pinctada maxima, promoted an increase in ALP activity that was dosedependent. In this work, we show that the effect of WSM is also timedependent. As a comparison, the effect of WSM was also tested in bone marrow stromal cells because marrow and other bone surfacederived osteoblast stem cells have the inherent direct potential for osteogenesis. WSM promotes cell proliferation and ALP activity when tested with bone marrow cells in concentrations between 135 and 540 μg proteinmL. The effect of WSM on ALP activity of bone marrow stromal cells is similar to that obtained by dexamethasone. These results imply that MRC5 fibroblasts respond to differentiating factors that promote osteoblastic phenotype in bonederived cell cultures. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res 57: 306–312, 2001
- Published
- 2001
- Full Text
- View/download PDF
232. Encapsulation of osteoprogenitor and endothelial cell co-cultures for bone tissue engineering application
- Author
-
Grellier, Maritie, Bidarra, Silvia J., Bareille, Reine, Fricain, Jean-Christophe, Granja, Pedro L., Barbosa, Mario A., and Amédée, Joelle
- Published
- 2008
- Full Text
- View/download PDF
233. Modulation of the In Vivo Inflammatory Response by Pro- Versus Anti-Inflammatory Intervertebral Disc Treatments.
- Author
-
Cunha, Carla, Q. Teixeira, Graciosa, Ribeiro-Machado, Cláudia, L. Pereira, Catarina, Ferreira, Joana R., Molinos, Maria, G. Santos, Susana, Barbosa, Mário A., and M. Goncalves, Raquel
- Subjects
INTERVERTEBRAL disk ,NUCLEUS pulposus ,T cells ,BLOOD cells ,LYMPH nodes ,MACROPHAGES ,LUMBAR pain - Abstract
Inflammation is central in intervertebral disc (IVD) degeneration/regeneration mechanisms, and its balance is crucial to maintain tissue homeostasis. This work investigates the modulation of local and systemic inflammatory response associated with IVD degeneration/herniation by administration of PRO- versus ANTI-inflammatory treatments. Chitosan/poly-γ-glutamic acid nanocomplexes, known as pro-inflammatory (PRO), and soluble diclofenac, a non-steroidal anti-inflammatory drug (ANTI), were intradiscally administered in a rat IVD injury model, 24 h after lesion. Two weeks after administration, a reduction of disc height accompanied by hernia formation was observed. In the PRO-inflammatory treated group, IL-1β, IL-6 and COX-2 IVD gene expression were upregulated, and loss of nucleus pulposus (NP) structure and composition was observed. Systemically, lower T-cell frequency was observed in the lymph nodes (LN) and spleen (SP) of the PRO group, together with an increase in CD4+ T cells subset in the blood (BL) and LN. In contrast, the ANTI-group had higher proteoglycans/collagen ratio and collagen type 2 content in the NP, while an increase in the frequency of myeloid cells, M1 macrophages and activated macrophages (MHCII+) was observed at the systemic level. Overall, this study illustrates the dynamics of local and systemic inflammatory and immune cell responses associated with intradiscal therapies, which will contribute to designing more successful immunomodulatory treatments for IVD degeneration. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
234. The Systemic Immune Response to Collagen-Induced Arthritis and the Impact of Bone Injury in Inflammatory Conditions.
- Author
-
Teixeira, José H., Silva, Andreia M., Almeida, Maria Inês, Bessa-Gonçalves, Mafalda, Cunha, Carla, Barbosa, Mário A., and Santos, Susana G.
- Subjects
BONE injuries ,IMMUNE response ,ARTHRITIS ,RHEUMATOID arthritis ,FEMUR ,FRACTALKINE ,MESENCHYMAL stem cells - Abstract
Rheumatoid arthritis (RA) is a systemic disease that affects the osteoarticular system, associated with bone fragility and increased risk of fractures. Herein, we aimed to characterize the systemic impact of the rat collagen-induced arthritis (CIA) model and explore its combination with femoral bone defect (FD). The impact of CIA on endogenous mesenchymal stem/stromal cells (MSC) was also investigated. CIA induction led to enlarged, more proliferative, spleen and draining lymph nodes, with altered proportion of lymphoid populations. Upon FD, CIA animals increased the systemic myeloid cell proportions, and their expression of co-stimulatory molecules CD40 and CD86. Screening plasma cytokine/chemokine levels showed increased tumor necrosis factor-α (TNF-α), Interleukin (IL)-17, IL-4, IL-5, and IL-12 in CIA, and IL-2 and IL-6 increased in CIA and CIA+FD, while Fractalkine and Leptin were decreased in both groups. CIA-derived MSC showed lower metabolic activity and proliferation, and significantly increased osteogenic and chondrogenic differentiation markers. Exposure of control-MSC to TNF-α partially mimicked the CIA-MSC phenotype in vitro. In conclusion, inflammatory conditions of CIA led to alterations in systemic immune cell proportions, circulating mediators, and in endogenous MSC. CIA animals respond to FD, and the combined model can be used to study the mechanisms of bone repair in inflammatory conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
235. Engineering Anisotropic Cell Models: Development of Collagen Hydrogel Scaffolds with Magneto‐Responsive PEG Microgels for Tissue Engineering Applications.
- Author
-
Castro, Ana L., Vedaraman, Sitara, Haraszti, Tamás, Barbosa, Mário A., Gonçalves, Raquel M., and De Laporte, Laura
- Subjects
- *
MICROGELS , *RHEOLOGY , *POLYETHYLENE glycol , *COLLAGEN , *HYDROGELS , *GELATION , *TISSUE engineering , *RHEOLOGY (Biology) - Abstract
Mimicking tissue‐oriented organization in vitro has been extensively studied in recent years, using both natural and synthetic materials in combination with external magnetic fields to establish anisotropic conditions. Here, a new combination between magneto‐responsive anisometric PEG microgels and collagen hydrogels is explored to establish anisotropic in vitro models. Different sizes of PEG microgels are tested to assess the impact of both width and aspect ratio on the formation and alignment of collagen hydrogels. Results show that the key properties of collagen hydrogels, regarding fibrillogenesis, rheological properties, and fiber diameter are kept consistent upon the combination with PEG microgels. Furthermore, partial collagen fiber alignment is observed when larger (width 10 µm) PEG microgels are employed and magnetically aligned. In vitro studies show cell alignment within the anisotropic collagen hydrogels from the first day in culture. Interestingly, PEG microgels with higher width and length tend to induce less hydrogel contraction even after 7 days in culture. The results demonstrate the ability to establish a 3D unidirectional collagen hydrogel by magnetically aligning anisometric microgels during the gelation process, which can be promising for different tissue engineering applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
236. Passivation kinetics and Pitting Studies on Cr, Ni and an 18Cr-10Ni Stainless Steel
- Author
-
Barbosa, Mário Adolfo Monteiro da Rocha
- Subjects
fungi ,technology, industry, and agriculture ,Metalurgia - Published
- 1980
237. Long noncoding RNAs: a missing link in osteoporosis
- Author
-
Silva, Andreia Machado, Moura, Sara Reis, Teixeira, José Henrique, Barbosa, Mário Adolfo, Santos, Susana Gomes, and Almeida, Maria Inês
- Abstract
Osteoporosis is a systemic disease that results in loss of bone density and increased fracture risk, particularly in the vertebrae and the hip. This condition and associated morbidity and mortality increase with population ageing. Long noncoding (lnc) RNAs are transcripts longer than 200 nucleotides that are not translated into proteins, but play important regulatory roles in transcriptional and post-transcriptional regulation. Their contribution to disease onset and development is increasingly recognized. Herein, we present an integrative revision on the studies that implicate lncRNAs in osteoporosis and that support their potential use as therapeutic tools. Firstly, current evidence on lncRNAs involvement in cellular and molecular mechanisms linked to osteoporosis and its major complication, fragility fractures, is reviewed. We analyze evidence of their roles in osteogenesis, osteoclastogenesis, and bone fracture healing events from human and animal model studies. Secondly, the potential of lncRNAs alterations at genetic and transcriptomic level are discussed as osteoporosis risk factors and as new circulating biomarkers for diagnosis. Finally, we conclude debating the possibilities, persisting difficulties, and future prospects of using lncRNAs in the treatment of osteoporosis.
- Published
- 2019
- Full Text
- View/download PDF
238. Genetically Engineered-MSC Therapies for Non-unions, Delayed Unions and Critical-size Bone Defects.
- Author
-
Freitas, Jaime, Santos, Susana Gomes, Gonçalves, Raquel Madeira, Teixeira, José Henrique, Barbosa, Mário Adolfo, and Almeida, Maria Inês
- Subjects
BONE regeneration ,BONES ,STROMAL cells ,GENETIC engineering ,BONE fractures ,MESENCHYMAL stem cells ,INTRAMEDULLARY rods - Abstract
The normal bone regeneration process is a complex and coordinated series of events involving different cell types and molecules. However, this process is impaired in critical-size/large bone defects, with non-unions or delayed unions remaining a major clinical problem. Novel strategies are needed to aid the current therapeutic approaches. Mesenchymal stem/stromal cells (MSCs) are able to promote bone regeneration. Their beneficial effects can be improved by modulating the expression levels of specific genes with the purpose of stimulating MSC proliferation, osteogenic differentiation or their immunomodulatory capacity. In this context, the genetic engineering of MSCs is expected to further enhance their pro-regenerative properties and accelerate bone healing. Herein, we review the most promising molecular candidates (protein-coding and non-coding transcripts) and discuss the different methodologies to engineer and deliver MSCs, mainly focusing on in vivo animal studies. Considering the potential of the MSC secretome for bone repair, this topic has also been addressed. Furthermore, the promising results of clinical studies using MSC for bone regeneration are discussed. Finally, we debate the advantages and limitations of using MSCs, or genetically-engineered MSCs, and their potential as promoters of bone fracture regeneration/repair. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
239. The inflammatory response in the regression of lumbar disc herniation.
- Author
-
Cunha, Carla, Silva, Ana J., Pereira, Paulo, Vaz, Rui, Gonçalves, Raquel M., and Barbosa, Mário A.
- Published
- 2018
- Full Text
- View/download PDF
240. Decellularized Scaffolds for Intervertebral Disc Regeneration.
- Author
-
Fiordalisi, Morena, Silva, Ana João, Barbosa, Mário, Gonçalves, Raquel, and Caldeira, Joana
- Subjects
- *
INTERVERTEBRAL disk , *LUMBAR pain , *TISSUE engineering - Abstract
In the last decade, intervertebral disc (IVD) decellularization has gained significant attention for tissue regenerative purposes as a successful therapeutic alternative for low back pain (LBP). We discuss the recent advances in IVD decellularization, repopulation, and sterilization procedures, highlighting the major challenges that need to be addressed for clinical translation. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
241. Ionizing radiation modulates human macrophages towards a pro-inflammatory phenotype preserving their pro-invasive and pro-angiogenic capacities.
- Author
-
Teresa Pinto, Ana, Laranjeiro Pinto, Marta, Patrícia Cardoso, Ana, Monteiro, Cátia, Teixeira Pinto, Marta, Filipe Maia, André, Castro, Patrícia, Figueira, Rita, Monteiro, Armanda, Marques, Margarida, Mareel, Marc, dos Santos, Susana Gomes, Seruca, Raquel, Adolfo Barbosa, Mário, Rocha, Sónia, and José Oliveira, Maria
- Published
- 2016
- Full Text
- View/download PDF
242. Alterations of bovine nucleus pulposus cells with aging.
- Author
-
Molinos, Maria, Fiordalisi, Morena F., Caldeira, Joana, Almeida, Catarina R., Barbosa, Mário A., and Gonçalves, Raquel M.
- Subjects
- *
NUCLEUS pulposus , *PROTEIN expression , *INTERVERTEBRAL disk , *LUMBAR pain , *CELL morphology - Abstract
Aging is one of the major etiological factors driving intervertebral disc (IVD) degeneration, the main cause of low back pain. The nucleus pulposus (NP) includes a heterogeneous cell population, which is still poorly characterized. Here, we aimed to uncover main alterations in NP cells with aging. For that, bovine coccygeal discs from young (12 months) and old (10–16 years old) animals were dissected and primary NP cells were isolated. Gene expression and proteomics of fresh NP cells were performed. NP cells were labelled with propidium iodide and analysed by flow cytometry for the expression of CD29, CD44, CD45, CD146, GD2, Tie2, CD34 and Stro‐1. Morphological cell features were also dissected by imaging flow cytometry. Elder NP cells (up‐regulated bIL‐6 and bMMP1 gene expression) presented lower percentages of CD29+, CD44+, CD45+ and Tie2+ cells compared with young NP cells (upregulated bIL‐8, bCOL2A1 and bACAN gene expression), while GD2, CD146, Stro‐1 and CD34 expression were maintained with age. NP cellulome showed an upregulation of proteins related to endoplasmic reticulum (ER) and melanosome independently of age, whereas proteins upregulated in elder NP cells were also associated with glycosylation and disulfide bonds. Flow cytometry analysis of NP cells disclosed the existence of 4 subpopulations with distinct auto‐fluorescence and size with different dynamics along aging. Regarding cell morphology, aging increases NP cell area, diameter and vesicles. These results contribute to a better understanding of NP cells aging and highlighting potential anti‐aging targets that can help to mitigate age‐related disc disease. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
243. Chitosan 3D scaffolds with resolvin D1 for vertebral arthrodesis: a pilot study.
- Author
-
Vasconcelos, Daniela P., Costa, Madalena, Reis, Joaquim L., Pinto, Vasco S., Sousa, Ana B., Águas, Artur P., Barbosa, Mário A., and Barbosa, Judite N.
- Subjects
- *
ARTHRODESIS , *CHITOSAN , *PILOT projects , *BONE substitutes , *TISSUE scaffolds - Abstract
Purpose: Over the last years, the number of vertebral arthrodesis has been steadily increasing. The use of iliac crest bone autograft remains the "gold standard" for bone graft substitute in these procedures. However, this solution has some side effects, such as the problem of donor site morbidity indicating that there is a real need for adequate alternatives. This pilot study aimed to evaluate the usefulness of chitosan (Ch) porous 3D scaffolds incorporated with resolvin D1 (RvD1) as an alternative implant to iliac bone autograft. Methods: We have performed bilateral posterolateral lumbar vertebral arthrodesis in a rat animal model. Three experimental groups were used: (i) non-operated animals; (ii) animals implanted with Ch scaffolds incorporated with RvD1 and (iii) animals implanted with iliac bone autograft. Results: The collagenous fibrous capsule formed around the Ch scaffolds with RvD1 is less dense when compared with the iliac bone autograft, suggesting an important anti-inflammatory effect of RvD1. Additionally, new bone formation was observed in the Ch scaffolds with RvD1. Conclusion: These results demonstrate the potential of these scaffolds for bone tissue repair applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
244. Long non-coding RNA H19 regulates matrisome signature and impacts cell behavior on MSC-engineered extracellular matrices.
- Author
-
Moura, Sara Reis, Freitas, Jaime, Ribeiro-Machado, Cláudia, Lopes, Jorge, Neves, Nuno, Canhão, Helena, Rodrigues, Ana Maria, Barbosa, Mário Adolfo, and Almeida, Maria Inês
- Subjects
- *
LINCRNA , *EXTRACELLULAR matrix , *BONE regeneration , *ADIPOGENESIS , *ATOMIC force microscopy , *STROMAL cells , *VITRONECTIN , *COLLAGEN - Abstract
Background: The vast and promising class of long non-coding RNAs (lncRNAs) has been under investigation for distinct therapeutic applications. Nevertheless, their role as molecular drivers of bone regeneration remains poorly studied. The lncRNA H19 mediates osteogenic differentiation of Mesenchymal Stem/Stromal Cells (MSCs) through the control of intracellular pathways. However, the effect of H19 on the extracellular matrix (ECM) components is still largely unknown. This research study was designed to decode the H19-mediated ECM regulatory network, and to reveal how the decellularized siH19-engineered matrices influence MSC proliferation and fate. This is particularly relevant for diseases in which the ECM regulation and remodeling processes are disrupted, such as osteoporosis. Methods: Mass spectrometry-based quantitative proteomics analysis was used to identify ECM components, after oligonucleotides delivery to osteoporosis-derived hMSCs. Moreover, qRT-PCR, immunofluorescence and proliferation, differentiation and apoptosis assays were performed. Engineered matrices were decellularized, characterized by atomic force microscopy and repopulated with hMSC and pre-adipocytes. Clinical bone samples were characterized by histomorphometry analysis. Results: Our study provides an in-depth proteome-wide and matrisome-specific analysis of the ECM proteins controlled by the lncRNA H19. Using bone marrow-isolated MSC from patients with osteoporosis, we identified fibrillin-1 (FBN1), vitronectin (VTN) and collagen triple helix repeat containing 1 (CTHRC1), among others, as having different pattern levels following H19 silencing. Decellularized siH19-engineered matrices are less dense and have a decreased collagen content compared with control matrices. Repopulation with naïve MSCs promotes a shift towards the adipogenic lineage in detriment of the osteogenic lineage and inhibits proliferation. In pre-adipocytes, these siH19-matrices enhance lipid droplets formation. Mechanistically, H19 is targeted by miR-29c, whose expression is decreased in osteoporotic bone clinical samples. Accordingly, miR-29c impacts MSC proliferation and collagen production, but does not influence ALP staining or mineralization, revealing that H19 silencing and miR-29c mimics have complementary but not overlapping functions. Conclusion: Our data suggest H19 as a therapeutic target to engineer the bone ECM and to control cell behavior. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
245. Kinetics and isotherm of fibronectin adsorption to three-dimensional porous chitosan scaffolds explored by 125I-radiolabelling
- Author
-
Amaral, Isabel F., Sousa, Susana R., Neiva, Ismael, Marcos-Silva, Lara, Kirkpatrick, Charles J., Barbosa, Mário A., and Pêgo, Ana P.
- Abstract
In this study, 125I-radiolabelling was explored to follow the kinetics and isotherm of fibronectin (FN) adsorption to porous polymeric scaffolds, as well as to assess the elution and exchangeability of pre-adsorbed FN following incubation in serum-containing culture medium. Chitosan (CH) porous scaffolds with two different degrees of acetylation (DA 4% and 15%) were incubated in FN solutions with concentrations ranging from 5 to 50 µg/mL. The kinetic and isotherm of FN adsorption to CH were successfully followed using 125I-FN as a tracer molecule. While on DA 4% the levels of adsorbed FN increased linearly with FN solution concentration, on DA 15% a saturation plateau was attained, and FN adsorbed amounts were significantly lower. These findings were supported by immunofluorescent studies that revealed, for the same FN solution concentration, higher levels of exposed cell-binding domains on DA 4% as compared with DA 15%. Following incubation in serum containing medium, DA 4% also revealed higher ability to exchange pre-adsorbed FN by new FN molecules from serum than DA 15%. In accordance, when assessing the efficacy of passively adsorbed FN to promote endothelial cell (EC) adhesion to CH, ECs were found to adhere at higher levels to DA 4% as compared with DA 15%, 5 µg/mL of FN being already efficient in promoting cell adhesion and cytoskeletal organization on CH with DA 4%. Taken together the results show that protein radiolabelling can be used as an effective tool to study protein adsorption to porous polymeric scaffolds, both from single and complex protein solutions.
- Published
- 2013
- Full Text
- View/download PDF
246. Stress-induced depressive-like behavior in male rats is associated with microglial activation and inflammation dysregulation in the hippocampus in adulthood.
- Author
-
Brás, João Paulo, Guillot de Suduiraut, Isabelle, Zanoletti, Olivia, Monari, Silvia, Meijer, Mandy, Grosse, Jocelyn, Barbosa, Mário Adolfo, Santos, Susana Gomes, Sandi, Carmen, and Almeida, Maria Inês
- Subjects
- *
RATS , *MICROGLIA , *MENTAL depression , *IMMOBILIZATION stress , *DRUG target , *ADULTS , *DYSTHYMIC disorder - Abstract
• PPS induces protracted depressive-like behaviors in H-CSR male rats. • H-CSR PPS rats have increased hippocampal TNF-α and microglia activation. • miR-342 is upregulated in the hippocampus of H-CSR PPS rats. • miR-342 expression positively correlates with TNF-α and microglial activation. • Depressive-like behaviors are associated with increased miR-342 expression. Neuroinflammation is increasingly recognized as playing a critical role in depression. Early-life stress exposure and constitutive differences in glucocorticoid responsiveness to stressors are two key risk factors for depression, but their impacts on the inflammatory status of the brain is still uncertain. Moreover, there is a need to identify specific molecules involved in these processes with the potential to be used as alternative therapeutic targets in inflammation-related depression. Here, we studied how peripubertal stress (PPS) combined with differential corticosterone (CORT)-stress responsiveness (CSR) influences depressive-like behaviors and brain inflammatory markers in male rats in adulthood, and how these alterations relate to microglia activation and miR-342 expression. We found that high-CORT stress-responsive (H-CSR) male rats that underwent PPS exhibited increased anhedonia and passive coping responses in adulthood. Also, animals exposed to PPS showed increased hippocampal TNF-α expression, which positively correlated with passive coping responses. In addition, PPS caused long-term effects on hippocampal microglia, particularly in H-CSR rats, with increased hippocampal IBA-1 expression and morphological alterations compatible with a higher degree of activation. H-CSR animals also showed upregulation of hippocampal miR-342, a mediator of TNF-α-driven microglial activation, and its expression was positively correlated with TNF-α expression, microglial activation and passive coping responses. Our findings indicate that individuals with constitutive H-CSR are particularly sensitive to developing protracted depression-like behaviors following PPS exposure. In addition, they show neuro-immunological alterations in adulthood, such as increased hippocampal TNF-α expression, microglial activation and miR-342 expression. Our work highlights miR-342 as a potential therapeutic target in inflammation-related depression. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
247. Protein adsorption and clotting time of pHEMA hydrogels modified with C18 ligands to adsorb albumin selectively and reversibly
- Author
-
Gonçalves, Inês C., Martins, M. Cristina L., Barbosa, Mário A., and Ratner, Buddy D.
- Subjects
- *
BLOOD protein absorption & adsorption , *BLOOD coagulation , *HYDROGELS , *NANOSTRUCTURED materials , *BIOMEDICAL materials , *ALBUMINS , *LIGANDS (Chemistry) - Abstract
Abstract: This work intended to create a nanostructured biomaterial that would bind albumin in a selective and reversible way in order to inhibit the adsorption of other blood proteins and therefore minimize activation of coagulation. Different levels of C18 ligand have been immobilized on poly(2-hydroxyethyl methacrylate) (pHEMA). We hypothesize that samples with intermediate amounts of C18 ligand would allow albumin to recognize them and bind through its hydrophobic pockets specific for long chain fatty acids. Surface characterization has confirmed increasing amounts of C18 ligand on pHEMA as the percentage of C18 in solution increases, with maximum coverage achieved in 10% C18 samples. Adsorption from pure albumin solution revealed a small decrease in albumin adsorption from pHEMA to 1% C18 and 2.5% C18 samples, but on surfaces with 5% or higher C18 the amount of adsorbed albumin increased as the percentage of C18 increased. Competitive adsorption studies in the presence of both albumin and fibrinogen, and in the presence of all plasma proteins showed that 1% C18 and 2.5% C18 were the only surfaces selective for albumin, and that the presence of all plasma proteins may even potentiate albumin adsorption. Reversibility studies demonstrated that both 2.5% C18 and 5% C18 samples exchange 125I-albumin selectively in the presence of both unlabeled albumin and plasma, but 2.5% C18 samples presented higher exchangeability rates (58%). Clotting times using recalcified plasma revealed that samples with none or small amounts of C18 (pHEMA to 5% C18) did not shorten the clotting time compared to the negative control (polystyrene), indicating low activation of the intrinsic coagulation cascade. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
248. The uptake of titanium ions by hydroxyapatite particles—structural changes and possible mechanisms
- Author
-
Ribeiro, Cristina Castro, Gibson, Iain, and Barbosa, Mário Adolfo
- Subjects
- *
PROPERTIES of matter , *INFRARED spectroscopy , *ELECTRON spectroscopy , *PHOTOELECTRON spectroscopy - Abstract
Abstract: In order to understand the effect of titanium ions on the molecular structure of hydroxyapatite (HAp), HAp powders were incubated in solutions with different titanium concentrations. After incubation, the powders obtained were analysed using different techniques, namely X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS). The results suggest that, depending on the concentration of titanium in solution, two different mechanisms of interaction with HAp occur. For concentrations equal to or smaller than 200ppm, the titanium uptake by the solid seems to be primarily due to incorporation in the lattice. For higher concentrations, a dissolution-precipitation process seems to occur, leading to formation of a titanium phosphate compound. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
- View/download PDF
249. Protein adsorption on 18-alkyl chains immobilized on hydroxyl-terminated self-assembled monolayers
- Author
-
Gonçalves, Inês Castro, Martins, Cristina L., Barbosa, Mário A., and Ratner, Buddy D.
- Subjects
- *
BLOOD coagulation , *PROTEINS , *FIBRINOGEN , *SPECTRUM analysis - Abstract
Abstract: Surfaces of devices that contact blood accumulate adsorbed and denatured proteins perhaps triggering activation of the coagulation system. A renewable layer of albumin would biologically “passivate” the surface and prevent thrombus formation. Based on the approach of selectively binding albumin to fatty acids, different percentages of a compound with 18 carbons (C18) were immobilized on OH-terminated self-assembled monolayers (SAMs). Fourier transform infrared reflection absorption spectroscopy (IRAS), ellipsometry, contact angle (and surface free energy) and X-ray photoelectron spectroscopy (XPS) measurements were used to characterize these surfaces and proved that there is an efficient immobilization of C18. There is an increase of the thickness and hydrophobicity of SAMs with an increasing percentage of C18. Adsorption of human serum albumin (HSA) was evaluated using radiolabelled 125I-HSA and IRAS. This study showed a gradual increase of HSA adsorption with the increase of surface hydrophobicity. Regarding competitive binding and exchangeability of albumin towards fibrinogen, it was proved, by radiolabelling, that SAMs prepared from solutions with 2.5% C18 presented considerable adsorption in a selective and reversible way. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
250. The attraction of Mac-1+ phagocytes during acute inflammation by methyl-coated self-assembled monolayers
- Author
-
Barbosa, Judite N., Madureira, Pedro, Barbosa, Mário A., and Águas, Artur P.
- Subjects
- *
PHAGOCYTES , *IMMUNE system , *CELLS , *LYMPHOCYTES - Abstract
Abstract: We have used self-assembled monolayers (SAMs) of alkanethiolates on gold to study the contribution of methyl terminal functional groups in implant-triggered inflammation. The CH3-coated biomaterials were inserted in an air-pouch cavity of the BALB/c mouse and the in situ inflammatory response was monitored 4, 24, 48 and 72 h later. Flow cytometry was applied to define surface expression of the adhesion receptor Mac-1 (CD11b/CD18), a marker of activated leukocytes, and also of CD3 and B220 antigens (T and B lymphocytes). The CH3-coated surfaces caused a significant enhancement in the number of Mac-1+ cells in the implant. The only significant change in T and B lymphocytes was a transient increase in T cells detected 48 h after the implantation. Peak numbers of Mac-1+ phagocytes were observed 24 h after implantation. We conclude that if CH3 is present at the surface of implants, this chemical group will trigger a significant enhancement of activated phagocytes involved in the inflammatory reaction, and this phenomenon may extend the local phlogistic event. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.