929 resultados para Articular cartilage Wounds and injuries


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Pós-graduação em Agronomia (Horticultura) - FCA

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Pós-graduação em Bases Gerais da Cirurgia - FMB

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Pós-graduação em Bases Gerais da Cirurgia - FMB

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Background Staphylococcus aureus is the most common agent of septic arthritis that is a severe, rapidly progressive and destructive joint disease. Superantigens produced by S. aureus are considered the major arthritogenic factors. In this study, we compared the arthritogenic potential of five superantigen-producing staphylococcal strains. Methods Male C57BL/6 mice were intravenously infected with ATCC 19095 SEC+, N315 ST5 TSST-1+, S-70 TSST-1+, ATCC 51650 TSST-1+ and ATCC 13565 SEA+ strains. Clinical parameters as body weight, arthritis incidence and clinical score were daily evaluated. Joint histopathological analysis and spleen cytokine production were evaluated at the 14th day after infection. Results Weight loss was observed in all infected mice. ATCC 19095 SEC+, N315 ST5 TSST-1+ and S-70 TSST-1+ were arthritogenic, being the highest scores observed in ATCC 19095 SEC+ infected mice. Intermediate and lower clinical scores were observed in N315 ST5 TSST-1+ and S-70 TSST-1+ infected mice, respectively. The ATCC 13565 SEA+ strain caused death of 85% of the animals after 48 h. Arthritis triggered by the ATCC 19095 SEC+ strain was characterized by accentuated synovial hyperplasia, inflammation, pannus formation, cartilage destruction and bone erosion. Similar joint alterations were found in N315 ST5 TSST-1+ infected mice, however they were strikingly more discrete. Only minor synovial proliferation and inflammation were triggered by the S-70 TSST-1+ strain. The lowest levels of TNF-α, IL-6 and IL-17 production in response to S. aureus stimulation were found in cultures from mice infected with the less arthritogenic strains (S-70 TSST-1+ and ATCC 51650 TSST-1+). The highest production of IL-17 was detected in mice infected with the most arthritogenic strains (ATCC 19095 SEC+ and N315 ST5 TSST-1+). Conclusions Together these results demonstrated that S. aureus strains, isolated from biological samples, were able to induce a typical septic arthritis in mice. These results also suggest that the variable arthritogenicity of these strains was, at least in part, related to their differential ability to induce IL-17 production.

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The relevance of human joint models has been shown in the literature. They can help in diagnosis, in prostheses and ortheses design and in predicting the joints’ behavior. Recently a sequential approach for the modeling of the human diarthrodial joints composed of three steps has been proposed. At each step the role of some anatomical structures is considered. Starting from a limited number of structures, the model gets more and more sophisticated until all the components, both passive (articular surfaces, ligaments and tendons) and active (muscles), are incorporated in the final model. According to this procedure, the behavior of the human ankle during passive motion (no loads applied) has been previously modeled by a one degree of freedom 5-5 fully parallel mechanism. Starting from this model, the kinetostatic model of the human ankle joint that replicates its behavior when external loads are applied is developed. The anatomical and mechanical characteristics and the role of the passive structures are considered; a multifiber model is developed and an optimization criteria based on experimental data is proposed. Finally an application of the developed model to an amputated ankle is presented, together with the results obtained from the optimization of the geometrical and mechanical Parameters. Although some improvements can be achieved, the model is satisfactorily able to replicate the behavior of the human ankle subject to the anterior drawer and the inversion clinical tests applied in the neutral position.

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The aim of this dissertation is to provide a trilingual translation from English into Italian and from Italian into Spanish of a policy statement from the Fédération Internationale de l’Automobile (FIA) regarding road safety. The document, named “Formula Zero: a strategy for reducing fatalities and injuries on track and road”, was published in June 2000 and involves an approach about road safety inspired by another approach introduced in Sweden called ‘Vision Zero’. This work consists of six sections. The first chapter introduces the main purposes and activities of the Federation, as well as the institutions related to it and Vision Zero. The second chapter presents the main lexical, morphosyntactic and stylistic features of the institutional texts and special languages. In particular, the text contains technical nomenclature of transports and elements of sport language, especially regarding motor sport and Formula One. In the third chapter, the methodology is explained, with all the resources used during the preliminary phase and the translation, including corpora, glossaries, expert consultancy and specialised sites. The fourth chapter focuses on the morphosyntactic and terminology features contained in the text, while the fifth chapter presents the source text and the target texts. The final chapter deals with all the translation strategies that are applied, alongside with all the challenging elements detected. Therefore, the dissertation concludes with some theoretical and practical considerations about the role of inverse translation and English as Lingua Franca (ELF), by comparing the text translated into Spanish to the original in English, using Italian as a lingua franca.

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OBJECTIVE: Myofibroblasts are responsible for contraction and scarring after cleft palate repair. This leads to growth disturbances in the upper jaw. We hypothesized that cells from the bone marrow are recruited to palatal wounds and differentiate into myofibroblasts. METHODS: We transplanted bone marrow from green fluorescent protein (GFP)-transgenic rats into lethally irradiated wild-type rats. After recovery, experimental wounds were made in the palatal mucoperiosteum, and harvested 2 weeks later. GFP-expressing cells were identified using immunostaining. Myofibroblasts, activated fibroblasts, endothelial cells, and myeloid cells were quantified with specific markers. RESULTS: After transplantation, 89 ± 8.9% of mononuclear cells in the blood expressed the GFP and about 50% of adherent cells in the bone marrow. Tissue obtained during initial wounding contained only minor numbers of GFP-positive cells, like adjacent control tissue. Following wound healing, 8.1 ± 5.1% of all cells in the wound area were positive, and 5.0 ± 4.0% of the myofibroblasts, which was significantly higher than in adjacent tissue. Similar percentages were found for activated fibroblasts and endothelial cells, but for myeloid cells it was considerably higher (22 ± 9%). CONCLUSIONS: Bone marrow-derived cells contribute to palatal wound healing, but are not the main source of myofibroblasts. In small wounds, the local precursor cells are probably sufficient to replenish the defect.

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Pes cavovarus affects the ankle biomechanics and may lead to ankle arthrosis. Quantitative T2 STAR (T2*) magnetic resonance (MR) mapping allows high resolution of thin cartilage layers and quantitative grading of cartilage degeneration. Detection of ankle arthrosis using T2* mapping in cavovarus feet was evaluated. Eleven cavovarus patients with symptomatic ankle arthrosis (13 feet, mean age 55.6 years, group 1), 10 cavovarus patients with no or asymptomatic, mild ankle arthrosis (12 feet, mean age 41.8 years, group 2), and 11 controls without foot deformity (18 feet, mean age 29.8 years, group 3) had quantitative T2* MR mapping. Additional assessment included plain radiographs and the American Orthopaedic Foot and Ankle Society (AOFAS) score (groups 1 and 2 only). Mean global T2* relaxation time was significantly different between groups 1 and 2 (p = 0.001) and groups 1 and 3 (p = 0.017), but there was no significance for decreased global T2* values in group 2 compared to group 3 (p = 0.345). Compared to the medial compartment T2* values of the lateral compartment were significantly (p = 0.025) higher within group 1. T2* values in the medial ankle joint compartment of group 2 were significantly lower than those of group 1 (p = 0.019). Ankle arthrosis on plain radiographs and the AOFAS score correlated significantly with T2* values in the medial compartment of group 1 (p = 0.04 and 0.039, respectively). Biochemical, quantitative T2* MR mapping is likely effective to evaluate ankle arthrosis in cavovarus feet but further studies are required.

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This case report describes the incidental finding of a calcified ligamentum arteriosum during post-mortem CT examination. The calcification of the ligament was confirmed at autopsy. Subsequent histological examination revealed the presence of cartilage-like and bone-like tissue as well as extended calcification areas. The importance of not confusing this normal post-mortem CT finding with vessel pathology is being emphasized.

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We report the longterm follow-up of children with optic nerve avulsion (ONA) caused by traumatic events. The remarkable differences in courses and outcomes may elucidate the spectrum of ONA-associated symptoms and injuries.

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Background It has been demonstrated that frequency modulation of loading influences cellular response and metabolism in 3D tissues such as cartilage, bone and intervertebral disc. However, the mechano-sensitivity of cells in linear tissues such as tendons or ligaments might be more sensitive to changes in strain amplitude than frequency. Here, we hypothesized that tenocytes in situ are mechano-responsive to random amplitude modulation of strain. Methods We compared stochastic amplitude-modulated versus sinusoidal cyclic stretching. Rabbit tendon were kept in tissue-culture medium for twelve days and were loaded for 1h/day for six of the total twelve culture days. The tendons were randomly subjected to one of three different loading regimes: i) stochastic (2 – 7% random strain amplitudes), ii) cyclic_RMS (2–4.42% strain) and iii) cyclic_high (2 - 7% strain), all at 1 Hz and for 3,600 cycles, and one unloaded control. Results At the end of the culture period, the stiffness of the “stochastic” group was significantly lower than that of the cyclic_RMS and cyclic_high groups (both, p < 0.0001). Gene expression of eleven anabolic, catabolic and inflammatory genes revealed no significant differences between the loading groups. Conclusions We conclude that, despite an equivalent metabolic response, stochastically stretched tendons suffer most likely from increased mechanical microdamage, relative to cyclically loaded ones, which is relevant for tendon regeneration therapies in clinical practice.

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Osteoarthritis is a chronic joint disease that involves degeneration of articular cartilage. Pre-clinical data suggest that doxycycline might act as a disease-modifying agent for the treatment of osteoarthritis, with the potential to slow cartilage degeneration. This is an update of a Cochrane review first published in 2009.

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Tissue engineering strategies are gathering clinical momentum in regenerative medicine and are expected to provide excellent opportunities for therapy for difficult-to-treat human pathologies. Being aware of the requirement to produce larger artificial tissue implants for clinical applications, we used microtissues, produced using gravity-enforced self-assembly of monodispersed primary cells, as minimal tissue units to generate scaffold-free vascularized artificial macrotissues in custom-shaped agarose molds. Mouse myoblast, pig and human articular-derived chondrocytes, and human myofibroblast (HMF)-composed microtissues (microm3 scale) were amalgamated to form coherent macrotissue patches (mm3 scale) of a desired shape. Macrotissues, assembled from the human umbilical vein endothelial cell (HUVEC)-coated HMF microtissues, developed a vascular system, which functionally connected to the chicken embryo's vasculature after implantation. The design of scaffold-free vascularized macrotissues is a first step toward the scale-up and production of artificial tissue implants for future tissue engineering initiatives.

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OBJECTIVE: To obtain precise information on the optimal time window for surgical antimicrobial prophylaxis. SUMMARY BACKGROUND DATA: Although perioperative antimicrobial prophylaxis is a well-established strategy for reducing the risk of surgical site infections (SSI), the optimal timing for this procedure has yet to be precisely determined. Under today's recommendations, antibiotics may be administered within the final 2 hours before skin incision, ideally as close to incision time as possible. METHODS: In this prospective observational cohort study at Basel University Hospital we analyzed the incidence of SSI by the timing of antimicrobial prophylaxis in a consecutive series of 3836 surgical procedures. Surgical wounds and resulting infections were assessed to Centers for Disease Control and Prevention standards. Antimicrobial prophylaxis consisted in single-shot administration of 1.5 g of cefuroxime (plus 500 mg of metronidazole in colorectal surgery). RESULTS: The overall SSI rate was 4.7% (180 of 3836). In 49% of all procedures antimicrobial prophylaxis was administered within the final half hour. Multivariable logistic regression analyses showed a significant increase in the odds of SSI when antimicrobial prophylaxis was administered less than 30 minutes (crude odds ratio = 2.01; adjusted odds ratio = 1.95; 95% confidence interval, 1.4-2.8; P < 0.001) and 120 to 60 minutes (crude odds ratio = 1.75; adjusted odds ratio = 1.74; 95% confidence interval, 1.0-2.9; P = 0.035) as compared with the reference interval of 59 to 30 minutes before incision. CONCLUSIONS: When cefuroxime is used as a prophylactic antibiotic, administration 59 to 30 minutes before incision is more effective than administration during the last half hour.