Designing biomaterials for bone-substitute applications is still a challenge regarding the natural complex structure of hard tissues. Aiming at bone regeneration applications, scaffolds based on ...natural collagen and synthetic nanohydroxyapatite were developed, and they showed adequate mechanical and biological properties. The objective of this work was to perform and evaluate a scaled-up production process of this porous biocomposite scaffold, which promotes bone regeneration and works as a barrier for both fibrosis and the proliferation of scar tissue. The material was produced using a prototype bioreactor at an industrial scale, instead of laboratory production at the bench, in order to produce an appropriate medical device for the orthopedic market. Prototypes were produced in porous membranes that were e-beam irradiated (the sterilization process) and then analysed by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), dynamic mechanical analysis (DMA), cytotoxicity tests with mice fibroblasts (L929), human osteoblast-like cells (MG63) and human MSC osteogenic differentiation (HBMSC) with alkaline phosphatase (ALP) activity and qPCR for osteogenic gene expression. The prototypes were also implanted into critical-size bone defects (rabbits' tibia) for 5 and 15 weeks, and after that were analysed by microCT and histology. The tests performed for the physical characterization of the materials showed the ability of the scaffolds to absorb and retain water-based solvents, as well as adequate mechanical resistance and viscoelastic properties. The cryogels had a heteroporous morphology with microporosity and macroporosity, which are essential conditions for the interaction between the cells and materials, and which consequently promote bone regeneration. Regarding the biological studies, all of the studied cryogels were non-cytotoxic by direct or indirect contact with cells. In fact, the scaffolds promoted the proliferation of the human MSCs, as well as the expression of the osteoblastic phenotype (osteogenic differentiation). The in vivo results showed bone tissue ingrowth and the materials' degradation, filling the critical bone defect after 15 weeks. Before and after irradiation, the studied scaffolds showed similar properties when compared to the results published in the literature. In conclusion, the material production process upscaling was optimized and the obtained prototypes showed reproducible properties relative to the bench development, and should be able to be commercialized. Therefore, it was a successful effort to harness knowledge from the basic sciences to produce a new biomedical device and enhance human health and wellbeing.
Mammary tumors similar to those observed in women can be induced in rats by intraperitoneal administration of N-methyl-N-nitrosourea. Determining tumor volume is a useful and quantitative way to ...monitor tumor progression. In this study, the authors measured dimensions of rat mammary tumors using a caliper and using real-time compound B-mode ultrasonography. They then used different formulas to calculate tumor volume from these tumor measurements and compared the calculated tumor volumes with the real tumor volume to identify the formulas that gave the most accurate volume calculations. They found that caliper and ultrasonography measurements were significantly correlated but that tumor volumes calculated using different formulas varied substantially. Mammary tumors seemed to take on an oblate spheroid geometry. The most accurate volume calculations were obtained using the formula V = (W(2) × L)/2 for caliper measurements and the formula V = (4/3) × π × (L/2) × (L/2) × (D/2) for ultrasonography measurements, where V is tumor volume, W is tumor width, L is tumor length and D is tumor depth.
Ultrasound (US) has emerged as one of the most applied imaging tools to diagnose musculoskeletal disorders and assist in guided intra-articular administrations. Nevertheless, in evaluating the rabbit ...hip joint, there is a need for an ultrasonographic approach. Therefore, this study aimed to describe the hip sonoanatomy, develop and validate a US-guided protocol to assess the hip joint in rabbits and apply this protocol in vivo. This study was carried out in three phases, phase I: a pilot cadaveric study, to assess the applicability of different US approaches in the hip of rabbits and, consequently, develop a detailed US-guided protocol (2 rabbit cadavers, n = 4 hips); phase II: validation of the established US-guided protocol through a numerical scoring system in healthy joints (11 rabbit cadavers, n = 22 hips), and, lastly, phase III: application of the US-guided protocol in vivo in osteoarthritic joints (5 rabbits, n = 5 hips). A total of six planes were validated, two in the ventral approach and four in the dorsal approach. The ventral transverse plane was deemed more informative regarding the hip joint sonoanatomy, enabling the identification of a greater number of structures when compared to the other planes. Nevertheless, this study suggested that the isolated application of a plane was deemed insufficient for a complete and detailed evaluation of the hip joint anatomy, rendering it necessary to employ other planes complementarily. Furthermore, the established US-guided protocol allowed a definitive diagnosis of OA, and osteophytes and capsular hypertrophy were among the defects most frequently detected. This novel study provided US anatomical landmarks for forthcoming therapeutic research and monitoring of OA development, granting the accurate identification of osseous and cartilaginous defects.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Mineral trioxide aggregate (MTA)-based sealers are endodontic materials with widespread success in distinct clinical applications, potentially embracing direct contact with the bone tissue. Bone ...response to these materials has been traditionally addressed in vitro. Nonetheless, translational data are limited by the absence of native cell-to-cell and cell-to-matrix interactions that hinder the representativeness of the analysis. Ex vivo organotypic systems, relying on the culture of explanted biological tissues, preserve the cell/tissue composition, reproducing the spatial and organizational in situ complexity. This study was grounded on an innovative research approach, relying on the assessment of an ex vivo organotypic bone tissue culture system to address the osteogenic response to 3 distinct MTA-based sealers.
Embryonic chick femurs were isolated and grown ex vivo for 11 days in the presence of MTA Plus (Avalon Biomed Inc, Bradenton, FL), ProRoot MTA (Dentsply Tulsa Dental, Hohnson City, Germany), Biodentine (Septodont, Saint Maurdes Fosses, France), or AH Plus (Dentsply Sirona, Konstanz, Germany); the latter was used as a control material. Femurs were characterized by histologic, histochemical, and histomorphometric analysis. Gene expression assessment of relevant osteogenic markers was conducted by quantitative polymerase chain reaction.
All MTA-based sealers presented an enhanced osteogenic performance compared with AH Plus. Histochemical and histomorphometric analyses support the increased activation of the osteogenic program by MTA-based sealers, with enhanced collagenous matrix deposition and tissue mineralization. Gene expression analysis supported the enhanced activation of the osteogenic program. Comparatively, ProRoot MTA induced the highest osteogenic functionality on the characterized femurs.
MTA-based sealers enhanced the osteogenic activity within the assayed organotypic bone model, which was found to be a sensitive system for the assessment of osteogenic modulation mediated by endodontic sealers.
Potential effects of sulforaphane to fight obesity Martins, Tânia; Colaço, Bruno; Venâncio, Carlos ...
Journal of the science of food and agriculture,
June 2018, Letnik:
98, Številka:
8
Journal Article
An innovative delivery system based on bacteriophages-loaded alginate-nanohydroxyapatite hydrogel was developed as a multifunctional approach for local tissue regeneration and infection prevention ...and control. Bacteriophages were efficiently encapsulated, without jeopardizing phage viability and functionality, nor affecting hydrogel morphology and chemical composition. Bacteriophage delivery occurred by swelling-disintegration-degradation process of the alginate structure and was influenced by environmental pH. Good tissue response was observed following the implantation of bacteriophages-loaded hydrogels, sustaining their biosafety profile. Bacteriophages-loaded hydrogels did not affect osteoblastic cells' proliferation and morphology. A strong osteogenic and mineralization response was promoted through the implantation of hydrogels system with nanohydroxyapatite. Lastly, bacteriophages-loaded hydrogel showed excellent antimicrobial activity inhibiting the attachment and colonization of multidrug-resistant E. faecalis surrounding and within femoral tissues. This new local delivery approach could be a promising approach to prevent and control bacterial contamination during implantation and bone integration.
An innovative delivery system based on bacteriophages-loaded alginate-nanohydroxyapatite hydrogel was developed as a multifunctional approach to prevent and control bacterial contamination, given the local delivery of phages and their ability to replicate at the site of infection, during the implantation and bone integration, promoted by nanoHA particles. Display omitted
Mesenchymal stromal cells‐based regenerative orthopedic therapies have been used in cats as a promising and innovative therapeutic approach to enhance the repair of bone defects. Adipose ...tissue‐derived stromal cells (ADSCs) can be obtained from two main sites—subcutaneous and visceral—with established differences regarding structure, composition, cell content, and functionality. However, in cats, to the best of the authors' knowledge, no studies have been conducted to compare the functional activity of the ADSCs isolated from the two sites, and the impact of these differences on the induced osteogenic potential. Additionally, retinoic acid has been recently regarded as a new osteogenic inducer within cells of distinct species, with undisclosed functionality on cat‐derived cell populations. Thus, the present study aimed to evaluate the functional activity of ADSCs isolated from the subcutaneous and visceral adipose sites (SCAT and VAT, respectively) of the cat, as well as the effects of two osteogenic‐inducing conditions—the classic dexamethasone, β‐glycerophosphate and ascorbic acid‐supplemented media (Dex + β + AAM), and Retinoic Acid‐supplemented media (RAM). The adipose tissue of subcutaneous and visceral origin was isolated, characterized, and ADSCs were isolated and grown in the presence of the two osteogenic‐inducing conditions, and characterized in terms of proliferation, metabolic activity, morphology, and osteogenic activity. Our results demonstrated a distinct biological profile of the two adipose tissue sites regarding cell size, vascularization, and morphology. Further, osteogenic‐induced ADSCs from both sites presented an increased expression of alkaline phosphatase activity (ALP) and cytochemical staining, as compared with control. Overall, RAM induced higher levels of ALP activity than Dex + β + AAM, supporting an increased osteogenic activation. Additionally, VAT was the tissue with the best osteogenic potential, showing higher levels of ALP expression, particularly with RAM. In conclusion, different characteristics were found between the two adipose tissue sites—SCAT and VAT, which probably reflect the differences found in the functionality of isolated ADSCs from both tissues. Furthermore, for cat, VAT shows a greater osteogenic‐inductive capacity than SCAT, particularly with RAM, which can be of therapeutic relevance for regenerative medicine applications.
Visceral adipose tissue‐derived stromal cells showed an increased osteogenic potential compared to subcutaneous adipose tissue‐derived cells. Retinoic acid effectively induced the osteogenic commitment of precursor populations, to a greater extent than classic osteogenic inducers.
•Manual restraint of animals for radiographic examination is common worldwide.•The negative effects of low doses of ionizing radiation on living tissues is known.•Radiographic diagnosis of canine hip ...dysplasia is a common procedure.•Hands-free diagnostic methods can reduce human exposure to ionizing radiation.
Hip dysplasia (HD) is one of the most common hereditary orthopaedic diseases in dogs, with serious implications for the quality of life of the affected animals. Radiographic screening is essential for the selection of breeding stock in some at-risk breeds, and radiography is also used in the diagnosis of clinical HD cases. A definitive diagnosis of HD is based on radiographic examination, and the most commonly used view is the ventrodorsal hip extended projection, sometimes in combination with various hip stress-based techniques. Radiographic images require high quality positioning and dogs are usually anesthetized and often manually restrained to facilitate optimal positioning. The ‘as low as reasonably achievable’ (ALARA) principle used in human radioprotection is not always fulfilled in veterinary practice, except in the UK, where human exposure to ionizing radiation in veterinary medicine is strictly regulated. While each dose of ionizing radiation is small, doses accumulate over a lifetime, which can eventually result in substantial radiation exposure. Therefore, manual restraint should be avoided and mechanical immobilization, sedation or general anaesthesia should be used. This review examines the biological effects of human exposure to ionizing radiation and common sources of veterinary exposure. The diagnostic quality of imaging methods for the diagnosis of canine HD is compared between manually restrained and hands-free dog positioning. Hands-free radiographic techniques are available to assess hip laxity, degenerative joint changes and hip osseous structure while preserving image quality, and can be used to select animals for breeding or for the diagnosis of HD.
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