Les lésions traumatiques de l’intestin sont responsables d’une part importante de la morbidité et de la mortalité consécutives aux lésions traumatiques abdominales. Elles sont pourtant mal connues. Les mécanismes à l’origine de ces blessures sont mal compris alors qu’un rôle paradoxalement négatif de l’usage de la ceinture de sécurité automobile est suspecté. En pratique clinique, le diagnostic précoce reste difficile, alors qu’une relation directe entre le délai diagnostic et le pronostic a été établi. Les règles de prise en charge thérapeutique ne sont pas consensuelles. Concernant la recherche, les quelques données de la littérature sur le comportement mécanique de l’intestin n’ont été obtenues qu’en condition quasi-statique ne reflétant pas les conditions d’un traumatisme. Le présent travail fait le lien entre données cliniques et travaux de recherche. Il apporte des connaissances pratiques sur un certain nombre de questions: quelles sont les situations à risque de chirurgie ? Comment se crée une lésion traumatique intestinale par décélération? Quelles sont les propriétés mécaniques de l’intestin qui dépendent de la cinétique du traumatisme ? Quelles sont les données anthropométriques et issues de l’imagerie médicale qui expliquent la variabilité de l’anatomie de l’intestin et de son mésentère ? Ces travaux serviront de base pour l’élaboration de modèles numériques d’hommes virtuels personnalisés et bio-fidèles utilisables dans le cadre de la traumatologie virtuelle. Ces outils de simulation numérique permettront de valider nos hypothèses sur le processus traumatique et participeront à l’amélioration des moyens de prévention de ces lésions traumatiques. / Traumatic injuries of the intestine are responsible for a significant proportion of the morbidity and mortality in blunt abdominal trauma. Nevertheless they are known very badly. The mechanisms involved are poorly understood despite the fact that a negative effect in the use of car seat belts is suspected. In clinical everyday practice, early diagnosis is often difficult, whereas a direct relationship between diagnosis delay and prognosis has been established. No consensus from academic society is available to help the therapeutic management. Regarding biomechanical research, the few data on the mechanical behavior of the intestine were obtained only in quasi-static condition and so does not reflect the conditions of trauma. The present work creates the link between clinical and research work. It provides practical knowledge on a number of questions: what situations are at risk of surgery? How intestinal injury occurs during traumatic deceleration? What are the mechanical properties of the intestine that depend on the velocity of trauma? What are the anthropometric data from medical imaging that explain the variability of the intestinal and mesenteric anatomy? This work constitutes the basis for the further development of numerical bio-faithful models of humans that could be used in virtual trauma applications. These numerical simulation tools will validate our assumptions about the traumatic process and will participate in the improvement of prevention means.

Meniscal tears are the most common intra-articular injury of the knee joint. Due to the avascular zone with limited blood supply, treatment of the injury is a complex process. Today, research on the development of efficient treatments and meniscal replacements is of increasing interest. However, there are few alternatives of meniscal replacements available on the market and research has shown uncertain results in their ability to restore the natural biomechanics of the knee joint or prevent development of osteoarthritis. Furthermore there is no comparable method to evaluate tensile stresses caused by axial compressional load on a whole meniscus replacement. Therefore the possibility of knitted casing to contain, fixate and mechanically stabilize a cell seeded bioprinted gel and develop a methodology to characterize its compressional behaviour was analysed. By interlock knitting with segments of partial knit a 3D crescent-shaped biodegradable casing was produced mimicking the dimension of the medial meniscus. In the casing design, an Artelon® Flexband™ was incorporated functioning both as reinforcement at the peripheral rim and as fixation method. Moreover radial threads were added to the casing design by inclusion of weft inlays in the knitting pattern. In the non-destructive characterization of the compressional behaviour of the prototype, axial compressional forces of 10.82 N and 29.77 N were achieved. However the forces achieved were significantly lower if compared to the high force that is applied to the menisci in the knee joint. Furthermore a high influence of the coefficient of friction of the casing in the axial compressional force was concluded. Nevertheless refinements of the methodology are required to perform evaluation with comparable and reliable results.

No description available.

Yes / There is a clinical need for novel graft materials for the repair of peripheral nerve defects. A decellularisation process has been developed for porcine peripheral nerves, yielding a material with potentially significant advantages over other devices currently being used clinically (such as autografts and nerve guidance conduits). Grafts derived from xenogeneic tissues should undergo sterilisation prior to clinical use. It has been reported that sterilisation methods may adversely affect the properties of decellularised tissues, and therefore potentially negatively impact on the ability to promote tissue regeneration. In this study, decellularised nerves were produced and sterilised by treatment with 0.1% (v/v) PAA, gamma radiation (25-28 kGy) or E Beam (33-37 kGy). The effect of sterilisation on the decellularised nerves was determined by cytotoxicity testing, histological staining, hydroxyproline assays, uniaxial tensile testing, antibody labelling for collagen type IV, laminin and fibronectin in the basal lamina, and differential scanning calorimetry. This study concluded that decellularised nerves retained biocompatibility following sterilisation. However, sterilisation affected the mechanical properties (PAA, gamma radiation), endoneurial structure and basement membrane composition (PAA) of decellularised nerves. No such alterations were observed following E Beam treatment, suggesting that this method may be preferable for the sterilisation of decellularised porcine peripheral nerves.

Submitted by Michele Mologni (mologni@unoeste.br) on 2019-01-23T12:44:40Z No. of bitstreams: 1 Marcelo Fernandes Tribst.pdf: 777315 bytes, checksum: b27a7e6b55bc34cf1e1df838b6e087c4 (MD5) / Made available in DSpace on 2019-01-23T12:44:40Z (GMT). No. of bitstreams: 1 Marcelo Fernandes Tribst.pdf: 777315 bytes, checksum: b27a7e6b55bc34cf1e1df838b6e087c4 (MD5) Previous issue date: 2018-09-21 / Smoking is a global concern because of the impact on public health, particularly in causing chronic illness and suffering for millions of people and is a leading cause of preventable deaths worldwide. The global annual cost of health services associated with smoking is estimated at US$ 422 billion, equivalent to US$ 56.34 per person. This represents 5.7% of total health expenditure in the world. The blend of cigarette smoke contains around 4.7000 toxic substances that are associated with decreased bone mass and influencing the process of bone healing and remodeling. Bone tissue being multifunctional and subject to cell differentiation at different stages of development is more susceptible to receiving the deleterious action of the main smoking agent of cigarette smoke. Functional, probiotic, prebiotic and symbiotic foods due to their ability to improve intestinal absorption and compete with pathogenic microorganisms may contribute to the improvement of bone quality. The objective of this study was to evaluate the effects of dietary supplementation of probiotic, prebiotic and symbiotic supplements on mineral composition, histomorphometry, biomechanical properties and fractal dimension of the femur of growing rats, chronically exposed to cigarette smoke (PT). Sixty-four young male rats were randomly assigned to eight groups (n = 8): control (C) [basal diet (DB)]; probiotic (Pro) [DB + probiotic (Lactobacillus acidophilus, Enterococcus faecium, Bifidobacterium thermophilum and Bifidobacterium longum (2-5 109 CFU each)], prebiotic (Pre) [DB + prebiotic (mannan oligosaccharide)], symbiotic probiotic + prebiotic + PT), prebiotic smoker (PreT) (DB + prebiotic + PT), smoker control (PT + The rats were sacrificed after 189 days of experimental period, and the results showed that probiotic, prebiotic and symbiotic supplementation improved significantly (P <0.05), as well as symbiotic smoker (SymT) (DB + prebiotic + probiotic + PT). The results showed that the functional food supplementation, probiotic, prebiotic, and the presence of the functional, probiotic, optical or symbiotic improved bone health in growing rats chronically exposed to cigarette smoke. / O tabagismo é uma preocupação global devido ao impacto na saúde pública, particularmente em causar doenças crônicas e sofrimento de milhões de pessoas e é uma das principais causas de mortes evitáveis em todo o mundo. Estima-se em US$ 422 bilhões o custo global anual dos serviços de saúde associados ao tabagismo, equivalente a US$ 56,34 por pessoa. Isso representa 5,7% do gasto total em saúde no mundo. A mistura da fumaça do cigarro contém por volta de 4.700 substâncias tóxicas que estão associados à diminuição de massa óssea e influenciando no processo de consolidação e remodelação óssea. O tecido ósseo por ser multifuncional e sujeito a diferenciação celular em diferentes estágios de desenvolvimento é mais susceptível a receber á ação deletéria da nicotina, principal agente agressor da fumaça do cigarro. Os alimentos funcionais, probiótico, prebiótico e simbiótico, devido sua capacidade de melhorar a absorção intestinal e competir com microrganismos patógenos podem contribuir para a melhora da qualidade óssea. O objetivo desse estudo foi avaliar os efeitos da suplementação na dieta de suplementos alimentares: probiótico, prebiótico e simbiótico, na composição mineral, histomorfometria, propriedades biomecânicas e dimensão fractal do fêmur de ratos em fase de crescimento, expostos cronicamente a fumaça do cigarro (PT). Sessenta e quatro ratos machos jovens foram randomicamente distribuídos em oito grupos (n=8): controle (C) [dieta basal (DB)]; probiótico (Pro) [DB + probiótico (Lactobacillus acidophilus, Enterococcus faecium, Bifidobacterium thermophilum e Bifidobacterium longum (2–5 109 UFC cada)]; prebiótico (Pre) [DB + prebiótico (mananoligossacarídeo)]; simbiótico (Sym) (DB + probiótico + prebiótico); controle fumante (CT) [DB + protocolo de exposição ao tabagismo passivo (PT)]; probiótico fumante (ProT) (DB + probiótico + PT); prebiótico fumante (PreT) (DB + prebiótico + PT); e simbiótico fumante (SymT) (DB + prebiótico + probiótico + PT). Os ratos foram sacrificados após a189 dias de período experimental e os resultados revelaram que a suplementação com probióticos, prebióticos e simbióticos melhoraram significativamente (P<0,05) os parâmetros: P, Ca, Mg, DMO, CMO, resistência, resiliência, dimensão fractal e tamanho da área das diáfises dos fêmures dos ratos expostos cronicamente ou não a fumaça do cigarro. Concluímos que a suplementação dos alimentos funcionais, probiótico, prebiótico ou simbiótico, melhorou a saúde óssea de ratos em fase de crescimento expostos cronicamente a fumaça do cigarro.

Gastrulation, literally “formation of the gut” is ultimately an inadequate term to describe one of the most dynamic periods during vertebrate developmental biology. During gastrulation coordinated cell movements reshape the non-descript blastula into the structured gastrula and simultaneously specify the three germ layers: endoderm, mesoderm and ectoderm. The morphogenetic movements of gastrulation are highly conserved between species, but the links between their genetic and biomechanical regulation are poorly understood. The zebrafish embryo – externally hatched, optically clear and amenable to genetic manipulation – is an ideal vertebrate model in which to study both morphogenetic movements and their genetic control. This thesis provides a detailed analysis of the zebrafish Mix-type homeobox transcription factor, Mtx2, both in terms of its role in gastrulation and the molecular mechanisms regulated by Mtx2. This approach involved detailed examination of the Mtx2 loss-of-function phenotype and, subsequently, use of this phenotype as the basis for a microarray screen to identify and investigate Mtx2-dependent genes. One specific Mtx2-dependent gene, katanin-like 1 was investigated further by loss-of-function studies. Prior to this study the mtx2 gene was identified by homology, within its homeodomain, to other Mix-family transcription factors, but both its function and transcriptional targets remained unknown. Using a morpholino knockdown approach, this thesis demonstrates that Mtx2 is essential for vegetal movement (epiboly), but not specification, of the embryonic germ layers and extra-embryonic tissues during zebrafish gastrulation. The recruitment of filamentous actin (F-actin) to a punctate band at the blastoderm margin, was previously shown to be responsible for progression of epiboly. However, formation of this structure is demonstrated to be Mtx2-dependent. Microarray expression profiling of the Mtx2 loss-of-function phenotype was performed to screen for novel genes with roles in gastrulation. This approach identified Mtx2-dependent genes with roles in cytoskeletal dynamics, cell-cell adhesion and endocytosis and vesicular trafficking – processes known to be involved in morphogenetic movements. Many Mtx2-dependent genes are co-expressed with mtx2 in the extra-embryonic yolk syncytial layer (YSL), the teleost functional equivalent of mammalian visceral endoderm. The subset of Mtx2-dependent genes co-expressed with mtx2 and that contain Mtx2-binding sites within their 2kb proximal promoter represent the genes with the greatest likelihood of being direct Mtx2 transcriptional targets. A novel homologue of the microtubule severing protein Katanin, known as katanin-like 1 (katnal1) met all these conditions. Morpholino knockdown of Katnal1 demonstrates that like Mtx2, Katnal1 is essential for gastrulation in zebrafish. A cloned Katnal1mCherry fusion construct was observed to associate with microtubules, and demonstrated bi-directional trafficking around transfected mammalian cells. Analysis of the microtubule network in wild-type and morpholino injected zebrafish embryos demonstrated that remodelling of the extensive microtubule network found in the YSL and yolk cytoplasmic layer (YCL) is Katnal1-dependent. Nuclear division within the YSL and F-actin recruitment to the blastoderm margin are also Katnal1-dependent. This thesis therefore demonstrates, for the first time directly, the multiple, specific roles played by the microtubule network of the YSL/YCL. Katnal1 is highly conserved from Drosophila to mammals and is dynamically expressed during mouse gastrulation. The Mtx2 binding motif in the katnal1 2kb proximal promoter can be bound by both Mtx2 and its putative mouse homologue Mixl1. This suggests that katnal1 may also be a direct target of Mtx2. At the technical level, these results demonstrate the validity of screening for novel developmentally important genes using a zebrafish microarray-based approach, the potential of such an approach to, ab initio, identify a candidate list of transcription factor targets and confirm the utility of the zebrafish as a developmental model. At the biological level, this work collectively suggests that Mtx2 is a central regulator of the morphogenetic movement of epiboly and that Katnal1-dependent microtubule remodelling drives multiple aspects of gastrulation, potentially from Drosophila through to humans.

Made available in DSpace on 2016-06-02T19:22:06Z (GMT). No. of bitstreams: 1 3395.pdf: 2690333 bytes, checksum: 00f09a0b23fd204a83ebf1fa55f2b3ed (MD5) Previous issue date: 2010-10-08 / Financiadora de Estudos e Projetos / The aim of this study was to investigate the effects of lead on femurs and vertebrae during development and skeletal maturity of female rats. For this purpose, one month old female rats were treated with lead acetate 100mg/kg BW or saline 0,9% 0,1ml/100g BW . The treatment was administrated by gastric gavage, once a week, during two months. After the treatment period, the animals received only tap water and commercial chow ad libitum until they completed 6, 9 and 12 months of life. The 3 months old groups were sacrificed soon after the treatment. The incorporation of lead in bone tissue occurred in all groups of intoxicated animals. The lead did not interfere the body development of experimental animals. The lead intoxication induced reduced maximum load, stiffness and resilience of the femur in the threepoint bending test in the groups 6, 9 and 12 months of life. The compression test of vertebrae of contaminated rats showed reduction of biomechanical parameters only in skeletally mature rats (9 months). The present study revealed that lead exposure during early stage of development affected the bone mineral profile leading to biomechanical weakness with skeletal maturity. The results allow us to conclude that lead exposure affects the biomechanical properties of mature bone increasing susceptibility to fractures. / O objetivo deste trabalho foi investigar os efeitos do chumbo sobre fêmures e vértebras de ratas durante seu desenvolvimento e maturidade esquelética. Para este propósito, ratas com um mês de idade foram intoxicadas com acetato de chumbo 100mg/Kg de massa corporal, e os grupos controles tratados com salina 0,9% 0,1 ml/100g de massa corporal. O tratamento foi realizado via gavagem gástrica, uma vez por semana, durante 2 meses. Após este período, a contaminação foi cessada e os animais receberam apenas água e ração comercial ad libitum até completarem 6, 9 e 12 meses de vida, sendo os animais do grupo 3 meses eutanasiados ao final do tratamento. A incorporação do chumbo no tecido ósseo ocorreu em todos os grupos de animais intoxicados. O chumbo não prejudicou o desenvolvimento corporal dos animais experimentais. No teste de flexão a três pontos, foi observada a redução da força máxima, rigidez e resiliência dos fêmures dos animais contaminados dos grupos 6, 9 e 12 meses. Nas vértebras (teste de compressão), esta redução foi evidente em ratas maduras esqueléticamente (9 meses de idade). O presente estudo revelou que a exposição ao chumbo, durante o estágio inicial de desenvolvimento esquelético, afeta o perfil mineral ósseo levando ao enfraquecimento biomecânico com a maturidade esquelética. Os resultados nos levam a concluir que a exposição ao chumbo afeta as propriedades biomecânicas do osso maduro aumentando a predisposição à fraturas.

Spolu s narastajúcimi nárokmi na kvalitu liečby v oblasti popálenin a plastickej chirurgie existuje možnosť ako uplatniť nové technologické riešenie na liečbu porúch s celkovou stratou kožnej vrstvy. Diplomová práca sa zaoberá prípravou nanoštrukturovaného, dvojvrstvového skafoldu pre využitie v tkánivovom inžinierstve, ktorý nahrádza kožnú časť dermis (dolná porézna vrstva) a bazálnu membránu (horná a tenká nanovlákenná vrstva). Zákaldom dolnej pórovitej vrstvy je kolagén, charakterizovaný v prítomnosti ďalších polysacharidových aditív: chitosan, vápenatá soľ oxidovanej celulózy (CaOC), sodná soľ karboxymetylcelulózy (NaCMC). Zároveň prídavok dopamínu a fibroblastového rastového faktoru (FGF), s cieľom zlepšiť biomechanické vlastnosti, regulovať a podporovať hojenie kože. Tenká nanovlákenná vrstva je zložená zo želatíny, polycaprolaktónu (PCL) a CaOC. Sú navrhnuté dva rôzne mechnizmy prípravy skafoldu, ktoré sa odlišujú sa v prítomnosti sieťovaných a nesieťovaných nanovláken. Skafoldy boli charakterizované z hľadiska biomechanických, štruktúrnych vlastností a in vitro. Vrchná nanovlákenná vrstva poskytuje mechanickú podporu, ktorá je výrazne zvýšená prítomnosťou polydopamínu (PDA). Test botnania poréznej vrstvy skafoldu ukázal na dostatočne veľké póry, umožňujúce filtráciu buniek. Táto botnatosť bola znížená v prítomnosti PDA, ktorý má zároveň významný vplyv na časové predĺženie degrádácie v prítomnosti kolagenázy a lyzozýmu. Spolu s FGF výrazne podporil proliferizáciu a životaschopnosť myších fibroblastov. Nanoštrukturovaný, dvojvrstvový skafold má potenciál pre budúce aplikácie pri hojení rán, kedže sa vyznačuje dobrými mechanickými vlastnosťami a umožňuje bunkám adherovať, proliferovať a formovať extra celulárny matrix.

Previous studies have shown favourable properties for papaya bast fibres, with a Young's modulus of up to 10 GPa and a tensile strength of up to 100 MPa. Because the fibres remain as residues on papaya plantations across the tropics in large quantities, their use in the making of green composites would seem to be worthy of consideration. This study aims to show that such composites can have very suitable mechanical properties, comparable to or even better than the common wood plastic composites (WPCs), and as such, represent a promising raw material for composites and a low-cost alternative to wood.

Title: The effect of menstrual cycle phases on muscle tone Goals and methods: The aim of this thesis is to prove the effect of menstrual cycle phases and participating hormons on the viscoelastic properties of the sceletal calf muscle via the non-invasive myotonometer device. The research part of this thesis is a pilot study in which participated seven female probands aged inbetween 24 to 28. Each proband participated in four weekly tests. Only probands who had not used hormonal contraception for at least six months were selected. Results: The results of the tests are represented in graphs picturing parts of curves representing the force caused by the tip of the myotonometer. The muscle soleus tension is changing throughout the menstrual cycle but its impossible to eliminate other endogenous and exogenous factors. The measured relative values of muscle tension are different for each proband. The menstrual phase has the highest average value of muscle tension. However, it is not possible to make a generally valid conclusion. Key words: Menstrual cycle, menstrual phase, muscle tone, calf muscle, biomechanical properties, myotonometry, contraception 5