5 results on '"João R. Ferreira"'
Search Results
2. Three-dimensional multipotent progenitor cell aggregates for expansion, osteogenic differentiation and ‘in vivo’ tracing with AAV vector serotype 6
- Author
-
Y. Park, Wei Shou Hu, Richard Jude Samulski, Matthew L. Hirsch, João R. Ferreira, C. C. Ko, and L. Zhang
- Subjects
Pluripotent Stem Cells ,Bone Regeneration ,Transcription, Genetic ,Cellular differentiation ,Genetic Vectors ,Biology ,medicine.disease_cause ,Article ,Collagen Type I ,03 medical and health sciences ,0302 clinical medicine ,Osteogenesis ,In vivo ,Genetics ,medicine ,Animals ,Osteopontin ,Progenitor cell ,Bone regeneration ,Wnt Signaling Pathway ,Molecular Biology ,Adeno-associated virus ,030304 developmental biology ,0303 health sciences ,Gene Transfer Techniques ,Cell Differentiation ,Dependovirus ,Molecular biology ,Extracellular Matrix ,Rats ,Platelet Endothelial Cell Adhesion Molecule-1 ,Adult Stem Cells ,030220 oncology & carcinogenesis ,biology.protein ,Molecular Medicine ,Stem cell ,Octamer Transcription Factor-3 ,Stem Cell Transplantation ,Adult stem cell - Abstract
Multipotent adult progenitor cells (MAPC) are bone marrow-derived stem cells with a high growth rate suitable for therapeutical applications as three-dimensional (3D) aggregates. Combined applications of osteogenically differentiated MAPC (OD-MAPC) aggregates and adeno-associated viral vectors (AAV) in bone bioengineering are still deferred until information regarding expansion technologies, osteogenic potential, and AAV cytotoxicity and transduction efficiency is better understood. In this study, we tested whether self-complementary AAV (scAAV) can potentially be used as a gene delivery system in a OD-MAPC-based “in vivo” bone formation model in the craniofacial region. Both expansion of rat MAPC (rMAPC) and osteogenic differentiation with dexamethasone were also tested in 3D aggregate culture systems “in vitro” and “vivo”. Rat MAPCs (rMAPCs) grew as undifferentiated aggregates for 4 days with a population doubling time of 37h. After expansion, constant levels of Oct4 transcripts, and Oct4 and CD31 surface markers were observed, which constitute a hallmark of rMAPCs undifferentiated stage. Dexamethasone effectively mediated rMAPC osteogenic differentiation by inducing the formation of a mineralized collagen type I network, and facilitated the activation of the wnt/β-catenin, a crucial pathway in skeletal development. To investigate the genetic modification of rMAPCs grown as 3D aggregates prior to implantation, scAAV serotypes 2, 3, and 6 were evaluated. scAAV6 packaged with the enhanced green fluorescent protein expression cassette efficiently mediated long-term transduction (10 days) “in vitro” and “vivo”. The reporter transduction event allowed the tracing of OD-rMAPC (induced by dexamethasone) aggregates following OD-rMAPC transfer into a macro-porous hydroxyapatite scaffold implanted in a rat calvaria model. Furthermore, the scAAV6-transduced OD-rMAPC generated a bone-like matrix with a collagenous matrix rich in bone specific proteins (osteocalcin and osteopontin) in the scaffold macro-pores 10 days post-implantation. Newly formed bone was also observed in the interface between native bone and scaffold. The collective work supports future bone tissue engineering applications of 3D MAPC cultures for expansion, bone formation, and the ability to genetically alter these cells using scAAV vectors.
- Published
- 2012
3. Titanium-enriched hydroxyapatite-gelatin scaffolds with osteogenically differentiated progenitor cell aggregates for calvaria bone regeneration
- Author
-
Ricardo J. Padilla, João R. Ferreira, Ching Chang Ko, Kun Yoon, Ganokon Urkasemsin, Wei Shou Hu, and Kelly Goeckner
- Subjects
food.ingredient ,Bone Regeneration ,Cellular differentiation ,Biomedical Engineering ,Bioengineering ,Calvaria ,Biochemistry ,Gelatin ,Nanocomposites ,Biomaterials ,food ,Osteogenesis ,medicine ,Animals ,Progenitor cell ,Craniofacial ,Bone regeneration ,Titanium ,Tissue Scaffolds ,Chemistry ,Regeneration (biology) ,Multipotent Stem Cells ,Skull ,Cell Differentiation ,Original Articles ,Rats ,medicine.anatomical_structure ,Durapatite ,Microscopy, Fluorescence ,Multipotent Stem Cell ,Biomedical engineering - Abstract
Adequate bony support is the key to re-establish both function and esthetics in the craniofacial region. Autologous bone grafting has been the gold standard for regeneration of problematic large bone defects. However, poor graft availability and donor-site complications have led to alternative bone tissue-engineering approaches combining osteoinductive biomaterials and three-dimensional cell aggregates in scaffolds or constructs. The goal of the present study was to generate novel cell aggregate-loaded macroporous scaffolds combining the osteoinductive properties of titanium dioxide (TiO2) with hydroxyapatite-gelatin nanocomposites (HAP-GEL) for regeneration of craniofacial defects. Here we investigated the in vivo applicability of macroporous (TiO2)-enriched HAP-GEL scaffolds with undifferentiated and osteogenically differentiated multipotent adult progenitor cell (MAPC and OD-MAPC, respectively) aggregates for calvaria bone regeneration. The silane-coated HAP-GEL with and without TiO2 additives were polymerized and molded to produce macroporous scaffolds. Aggregates of the rat MAPC were precultured, loaded into each scaffold, and implanted to rat calvaria critical-size defects to study bone regeneration. Bone autografts were used as positive controls and a poly(lactic-co-glycolic acid) (PLGA) scaffold for comparison purposes. Preimplanted scaffolds and calvaria bone from pig were tested for ultimate compressive strength with an Instron 4411(®) and for porosity with microcomputerized tomography (μCT). Osteointegration and newly formed bone (NFB) were assessed by μCT and nondecalcified histology, and quantified by calcium fluorescence labeling. Results showed that the macroporous TiO2-HAP-GEL scaffold had a comparable strength relative to the natural calvaria bone (13.8±4.5 MPa and 24.5±8.3 MPa, respectively). Porosity was 1.52±0.8 mm and 0.64±0.4 mm for TiO2-HAP-GEL and calvaria bone, respectively. At 8 and 12 weeks postimplantation into rat calvaria defects, greater osteointegration and NFB were significantly present in the TiO2-enriched HAP-GEL constructs with OD-MAPCs, compared to the undifferentiated MAPC-loaded constructs, cell-free HAP-GEL with and without titanium, and PLGA scaffolds. The tissue-engineered TiO2-enriched HAP-GEL constructs with OD-MAPC aggregates present a potential useful therapeutic approach for calvaria bone regeneration.
- Published
- 2013
4. Temporomandibular Disorders and its Relationship with Fibromyalgia
- Author
-
Ana Mirian Velly, Hong Chen, João R. Ferreira, and James R. Fricton
- Subjects
Persistence (psychology) ,medicine.medical_specialty ,Orofacial pain ,business.industry ,Temporomandibular disorder ,Chronic pain ,medicine.disease ,stomatognathic diseases ,Mechanical Hyperalgesia ,Fibromyalgia ,Physical therapy ,medicine ,Chronic fatigue syndrome ,Joint disorder ,medicine.symptom ,business ,human activities - Abstract
Temporomandibular Disorder (TMD) is the second most common musculoskeletal condition resulting in orofacial pain and disability. Although most cases of Temporomandibular Muscle and Joint Disorders (TMJD) are mild and self-limiting, about 10% of TMJD patients develop severe disorders associated with chronic pain and disability. One in two patients seeking care still has pain 5 years later. The treatment of TMD has been an increasing financial burden, with annual U.S. costs doubling in the last decade to $4 billion annually. It has been found that fibromyalgia (FMS) plays a significant role in the persistence of TMD. This chapter reviews the characteristics and the relationship between TMD and FMS, highlighting the importance of this comorbid condition for the management of TMD.
- Published
- 2011
5. Stochastic Optimization of AISI 52100 Hard Turning With Six Sigma Capability Constraint
- Author
-
Alexandre F. Torres, Renata P. R. Miranda, Anderson P. Paiva, Paulo H. S. Campos, Pedro Paulo Balestrassi, and Joao R. Ferreira
- Subjects
Capability engineering optimization methods ,response surface methodology ,stochastic processes ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Hard turning optimization problems are usually approached using response surface methodology. By running designed experiments, researchers build analytical models to represent the outputs under interest. However, most studies focus on the expected values of the outputs, and only a few consider the variances of the models, even though there are several stochastic programming (SP) techniques available in the literature. Such variances may have a significant impact on the problem solution. This paper aims to optimize the AISI 52100 hardened steel turning process using SP. The decision variables are cutting speed, feed rate, and depth of cut, outputs have cost per part and material removal rate, and average surface roughness six sigma capability is modeled as a stochastic constraint. The SP method is also compared with the conventional one, which did not include the variances into the problem. The results show that taking the variability of the models into account is necessary to obtain a satisfactory process capability and to analyze different scenarios. Finally, this paper shows that competitive results can be achieved by simplifying the problem formulation.
- Published
- 2019
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.