Cette thèse porte sur quelques inégalités de type Trudinger-Moser et leurs applications à l'étude des injections de Sobolev qu'elles induisent dans les espaces d'Orlicz et à l'analyse d'équations aux dérivées partielles non linéaires à croissance exponentielle.Le travail qu'on présente ici se compose de trois parties. La première partie est consacrée à la description du défaut de compacité de l'injection de Sobolev 4D dans l'espace d'Orlicz dansle cadre radial.L'objectif de la deuxième partie est double. D'abord, on caractérise le défaut de compacité de l'injection de Sobolev 2D dans les différentes classes d'espaces d'Orlicz. Ensuite, on étudiel'équation de Klein-Gordon semi-linéaire avec non linéarité exponentielle, où la norme d'Orlicz joue un rôle crucial. En particulier, on aborde les questions d'existence globale, de complétude asymptotique et d'étude qualitative.Dans la troisième partie, on établit des inégalités optimales de type Adams, en étroite relation avec les inégalités de Hardy, puis on fournit une description du défaut de compacité des injections de Sobolev qu'elles induisent / This thesis focuses on some Trudinger-Moser type inequalities and their applications to the study of Sobolev embeddings they induce into the Orlicz spaces, and the investigation of nonlinear partial differential equations with exponential growth.The work presented here includes three parts. The first part is devoted to the description of the lack of compactness of the 4D Sobolev embedding into the Orlicz space in the radialframework.The aim of the second part is twofold. Firstly, we characterize the lack of compactness of the 2D Sobolev embedding into the different classes of Orlicz spaces. Secondly, we undertakethe study of the nonlinear Klein-Gordon equation with exponential growth, where the Orlicz norm plays a crucial role. In particular, issues of global existence, scattering and qualitativestudy are investigated.In the third part, we establish sharp Adams-type inequalities invoking Hardy inequalities, then we give a description of the lack of compactness of the Sobolev embeddings they induce

Acutely manifesting radicular pain syndromes associated with degenerations of the lower spine are frequent ailments with a high rate of recurrence. Part of the conservative management are periradicular infiltrations of analgesics and steroids. The purpose of this study is to evaluate the dependence of the clinical efficacy of CT-guided periradicular injections on the pattern of contrast distribution and to identify the best distribution pattern that is associated with the most effective pain relief. Using a prospective study design, 161 patients were included in this study, ensuring ethical standards. Statistical analysis was performed, with the level of statistical significance set at p = 0.05. A total of 37.9% of patients experienced significant but not long-lasting (four weeks on average) complete pain relief. A total of 44.1% of patients experienced prolonged, subjectively satisfying pain relief of more than four weeks to three months. A total of 18% of patients had complete and sustained relief for more than six months. A significant correlation exists between circumferential, large area contrast distribution including the zone of action between the disc and affected nerve root contrast distribution pattern with excellent pain relief. Our results support the value of CT-guided contrast injection for achieving a good efficacy, and, if necessary, indicative repositioning of the needle to ensure a circumferential distribution pattern of corticosteroids for the sufficient treatment of radicular pain in degenerative spine disease.

This master's thesis addresses the often overlooked aspect of transaction costs, capital injections, and withdrawals in fund management theory. The research collaboration with Havsfonden, a newly launched quantitative ESG investment fund, aims to enhance their understanding of transaction costs and capital injections while improving their investment model. The thesis includes a comprehensive literature review, the development of a portfolio model that integrates transaction costs and capital injections, and the numerical implementation and testing of the model using MATLAB. Three distinct models focusing on transaction costs, including linear, fixed, and a combination of both, were created. Additionally, three models were developed to examine capital injections, with one based on past performance and the others considering a constant inflow of capital. The findings indicate that our models provide reasonable implementation and effectively capture the nature of capital injections and transaction costs. / Den här uppsatsen ämnar belysa dem många gånger försummade områdena – transaktionskostnader och kapitalinjektioner – inom portföljeteorin. Uppsatsen är i samarbete med Havsfonden, en nylanserad kvantitativ ESG fond, och syftar till att utvidga förståelsen för hur transaktionskostnader och kapitalinjektioner beaktas och kan modelleras. Uppsatsen omfattar en litteraturstudie, ett ramverk som integrerar transaktionskostnader och kapitalinjektioner, samt en numerisk implementation i MATLAB. Tre modeller för transaktionskostnader har utvecklats, vilket omfattar linjära och fasta transaktionskostnader samt en kombinerad version. Därutöver har tre modeller för kapitalinjektioner utvecklas, varav en baseras på portföljens tidigare prestation, medan de andra baseras på ett konstant inflöde av kapital. Resultatet tyder på att modellerna har implementerats riktigt och lyckas skildra dem utmärkande attributen av transaktionskostnader och kapitalinjektioner.

The purpose of this investigation was first, to make a histological and cytological study of the testis of male frogs, Rana pipiens, and to determine if there were tissue or cellular changes as well as physiological effects caused by fish pituitary-extract injections. Second, to determine if injections of fish pituitary extract into immature female white mice caused histological changes in the ovaries and uteri.

La mitose est un processus hautement régulé, orchestré à la fois dans le temps et dans l’espace par l’action coordonnée des kinases et des phosphatases, qui contrôlent divers substrats pour garantir la bonne progression de la division cellulaire. Les rôles des kinases ont été largement étudiés et de nombreux inhibiteurs de kinases ont été développés. Toutefois, les fonctions des phosphatases restent moins bien comprises et les substrats clés qu’elles déphosphorylent doivent encore être identifiés. Pour approfondir notre compréhension du rôle des phosphatases durant la mitose, nous avons employé des approches multidisciplinaires incluant la phosphoprotéomique, la microscopie et la biochimie. Dans un premier temps, nous avons identifié les cibles potentielles de la protéine phosphatase 2A associée à sa sous-unité régulatrice B55/Tws dans la reformation de l’enveloppe nucléaire en fin de mitose chez la drosophile. Nos résultats montrent que PP2A-Tws déphosphoryle les résidus Ser50 et Ser54 de la protéine de la membrane nucléaire interne, Otefin. Cette déphosphorylation régule son interaction avec la protéine de liaison à la chromatine BAF, ainsi qu’avec les protéines de la lamina nucléaire, les Lamines et Otefin elle-même. Ces évènements de déphosphorylation sont essentiels pour la reformation de l’enveloppe nucléaire (EN) en fin de mitose et pour le développement embryonnaire chez la drosophile. Nous avons étendu ces analyses aux autres phosphatases PP1, PP2A et PP4, en utilisant la phosphoprotéomique pour identifier des substrats et des interacteurs potentiels. Parmi les découvertes notables, nous avons émis l’hypothèse que PP2A-B56 pourrait jouer un rôle au niveau des centrosomes, en se localisant aux centrosomes et en interagissant avec des protéines telles que Grip71, Ninein et plp. De plus, nos expériences montrent que la déplétion de Wdb seul n’entraîne pas d’anomalies significatives dans le nombre de centrosomes, alors que la co-déplétion de Wdb et Wrd entraîne une augmentation du nombre de cellules avec un nombre anormal de centrosomes. Ces résultats suggèrent une fonction potentielle de PP2A-B56 dans la régulation de la migration ou de la duplication des centrosomes. Enfin, nous avons développé une technique d’inhibition dans les embryons de drosophile, où un peptide composé de motifs linéaires courts (SLiM) est injecté pour inhiber spécifiquement l’action des phosphatases. Cette approche a non seulement permis de tester des hypothèses sur les fonctions des phosphatases, mais aussi de valider l’efficacité de cette technique d’inhibition spécifique. En sommes, nos résultats ont permis d’identifier des cibles potentielles pour les phosphatases PP1, PP2A et PP4, bien que de nombreux mécanismes de déphosphorylation restent à être élucidés. À l’avenir, des inhibiteurs spécifiques basés sur les SLiM pourraient être développés pour cibler les phosphatases, ouvrant ainsi de nouvelles perspectives thérapeutiques dans les pathologies associées à des dysfonctionnements mitotiques, comme le cancer. Mes travaux de recherche ont contribué significativement à la compréhension des mécanismes moléculaires sous-jacents à ces phosphatases, posant des bases solides pour les recherches futures. / Mitosis is a highly regulated process, orchestrated both in time and space by the coordinated action of kinases and phosphatases, which control various substrates to ensure the smooth progression of cell division. The roles of kinases have been extensively studied, and numerous kinase inhibitors have been developed. However, the functions of phosphatases remain less well understood, and the key substrates they dephosphorylate have yet to be identified. To further our understanding of the role of phosphatases during mitosis, we employed multidisciplinary approaches including phosphoproteomics, microscopy and biochemistry. First, we identified potential targets of protein phosphatase 2A associated with its regulatory subunit B55/Tws in nuclear envelope reformation at the end of mitosis in Drosophila. Our results show that PP2A-Tws dephosphorylates the Ser50 and Ser54 residues of the inner nuclear membrane protein, Otefin. This dephosphorylation regulates its interaction with the chromatin-binding protein BAF, as well as with the nuclear lamina proteins, Lamin, and Otefin itself. These dephosphorylation events are essential for nuclear envelope (NE) reformation at the end of mitosis and for embryonic development in Drosophila. We have extended these analyses to the other phosphatases PP1, PP2A and PP4, using phosphoproteomics to identify potential substrates and interactors. Among the notable findings, we hypothesized that PP2A-B56 might play a role at the centrosome level, localizing to centrosomes and interacting with proteins such as Grip71, Ninein and plp. Furthermore, our experiments show that depletion of Wdb alone does not result in significant abnormalities in centrosome number, whereas co-depletion of Wdb and Wrd results in an increase in the number of cells with abnormal centrosome numbers. These results suggest a potential function of PP2A-B56 in the regulation of centrosome migration or duplication. Finally, we developed an inhibition technique in Drosophila embryos, where a peptide composed of short linear motifs (SLiM) is injected to specifically inhibit phosphatase action. This approach not only allowed us to test hypotheses about phosphatase functions, but also to validate the efficacy of this specific inhibition technique. In sum, we have identified potential targets for the phosphatases PP1, PP2A and PP4, although many dephosphorylation mechanisms remain to be elucidated. In the future, specific SLiM-based inhibitors could be developed to target phosphatases, opening up new therapeutic perspectives in pathologies associated with mitotic dysfunction, such as cancer. My research has contributed significantly to our understanding of the molecular mechanisms underlying these phosphatases, laying a solid foundation for future research.

Cette thèse propose une approche originale de test de vulnérabilité Web à partir de modèles etdirigée par des patterns de tests, nommée PMVT. Son objectif est d’améliorer la capacité de détectionde quatre types de vulnérabilité majeurs, Cross-Site Scripting, Injections SQL, Cross-Site RequestForgery, et Privilege Escalation. PMVT repose sur l’utilisation d’un modèle comportemental del’application Web, capturant ses aspects fonctionnels, et sur un ensemble de patterns de test devulnérabilité qui adressent un type de vulnérabilité de manière générique, quelque soit le type del’application Web sous test.Par l’adaptation de technologies MBT existantes, nous avons développé une chaîne outillée complèteautomatisant la détection des quatre types de vulnérabilité. Ce prototype a été exprimenté et évaluésur deux applications réelles, actuellement utiliseés par plusieurs dizaines de milliers d’utilisateurs.Les résultats d’expérimentation démontrent la pertinence et de l’efficience de PMVT, notamment enaméliorant de façon significative la capacité de détection de vulnérabilités vis à vis des scannersautomatiques d’applications Web existants. / This thesis proposes an original approach, dubbed PMVT for Pattern-driven and Model-basedVulnerability Testing, which aims to improve the capability for detecting four high-profile vulnerabilitytypes, Cross-Site Scripting, SQL Injections, CSRF and Privilege Escalations, and reduce falsepositives and false negatives verdicts. PMVT relies on the use of a behavioral model of theapplication, capturing its functional aspects, and a set of vulnerability test patterns that addressvulnerabilities in a generic way. By adapting existing MBT technologies, an integrated toolchain that supports PMVT automates thedetection of the four vulnerability types in Web applications. This prototype has been experimentedand evaluated on two real-life Web applications that are currently used by tens of thousandsusers. Experiments have highlighted the effectiveness and efficiency of PMVT and shown astrong improvement of vulnerability detection capabilities w.r.t. available automated Web applicationscanners for these kind of vulnerabilities.

No description available.

Made available in DSpace on 2014-07-29T15:25:16Z (GMT). No. of bitstreams: 1 Tese Alan Ricardo Rassi.pdf: 1456250 bytes, checksum: c7e131ba3c1d15cc824df69f5c3dc3f6 (MD5) Previous issue date: 2011-10-08 / The objective of this study was to determine the levels of toxicity of two and three intravitreous injections of infliximab to the retina and choroid of albino rabbits by means of histological, electroretinographic and clinical ophthalmological tests. Twelve New Zealand albino rabbits (24 eyes) were used in the study. Each eye was given two (n=10) or three (n=10) serial intravitreous 2 mg injections of infliximab dissolved in 0.06 ml of saline, at monthly intervals. A separate group of rabbits (n=4 eyes) served as a control group. Ninety days after the first injection, the rabbits underwent electroretinographic and clinical ophthalmological tests. After being enucleated, the eyes underwent histological examination. No clinical ophthalmologic abnormalities were detected in the 24 eyes studied. The histological change noted was the presence of rare lymphocytes and eosinophiles in the posterior vitreous of four eyes subjected to two injections and six eyes subjected to three injections of infliximab, but it was not considered clinically significant. One clinically significant abnormality was found, a severe inflammatory reaction with vitreous exudates and ganglion cell edema in both eyes of a single rabbit, subjected to two to three injections of infliximab. The electroretinographic tests showed amplitudes that were on the average 12% smaller than those obtained before the treatment. However, there were no statistically significant differences when comparing amplitude or the implicit time between the pre and post-treatment electroretinographic findings, in all groups examined. Then, two and three intravitreous 2 mg injections of infliximab in eyes of rabbits at monthly intervals did not cause any changes after a 90-day follow-up, according to histological, electroretinographic tests and clinical ophthalmological evaluation. It was concluded that serial intravitreous infliximab doses to rabbits is a safe procedure. / O objetivo deste trabalho foi determinar os níveis de toxicidade de duas e três aplicações intravítreas de infliximabe na retina e coroide de coelhos albinos, por meio de exames clínicos oftalmológicos, eletrorretinográficos e histológicos. Foram utilizados doze coelhos albinos (24 olhos) da raça New Zealand. Cada olho recebeu duas (n=10 olhos) ou três (n=10 olhos) injeções intravítreas seriadas de 2 mg de infliximabe dissolvidos em 0,06 ml de solução salina, em intervalos mensais. Um grupo separado de olhos (n=4 olhos) serviu como controle. Noventa dias após a primeira injeção, os coelhos foram novamente submetidos a exames clínicos oftalmológicos e eletrorretinográfico e, após enucleados, os olhos foram submetidos a exame histológico. Nos 24 olhos estudados, não foram detectadas alterações clínicas oftalmológicas. A alteração histológica notada foi a presença de raros linfócitos e eosinófilos na região posterior do vítreo de quatro olhos submetidos a duas aplicações e de seis olhos que receberam três aplicações de infliximabe, mas sem significado clínico. Foi encontrada uma única alteração clinicamente significante, caracterizada como reação inflamatória grave, com presença de exsudatos vítreos nos dois olhos de um coelho, que foi submetido a duas e três aplicações de infliximabe. Os exames eletrorretinográficos mostraram amplitudes em média 12% menores do que aquelas obtidas antes do tratamento, porém sem diferenças estatisticamente significantes, comparando-se a amplitude ou o tempo implícito entre os achados eletrorretinográficos pré e pós-tratamento em todos os grupos examinados. Assim, duas e três aplicações intravítreas de infliximabe em olhos de coelhos em intervalos mensais, na dosagem de 2 mg, não provocaram alterações após seguimento de noventa dias, quer no exame histológico, na eletrorretinografia ou na avaliação clínica oftalmológica. Conclui-se que doses seriadas de infliximabe por via intravítrea em coelhos é um procedimento seguro.

O presente trabalho avaliou o papel da solução parenteral de fatores hepatotróficos nutricionais em animais com cirrose submetidos à hepatectomia parcial. Este procedimento é temido nestes animais devido à possibilidade de ocorrência de falência hepática aguda, já que a remoção de um fragmento do fígado reduz ainda mais a capacidade funcional de um órgão já comprometido. Além disso, é conhecido que o fígado cirrótico diminui sua capacidade regenerativa, fato que atrasa a recuperação do animal, bem como também regenera cirroticamente. Esses fatores, aliados, contribuem para uma considerável taxa de mortalidade pós-operatória. Porém, há algumas situações em que estes pacientes precisam ser submetidos a ressecções hepáticas, tais como traumas, infecções e neoplasias. De fato, a presença de hepatocarcinomas representa a maior indicação deste procedimento em fígados cirróticos. Por outro lado, tem-se mostrado que a administração parenteral de solução de fatores hepatotróficos nutricionais (FHN), uma mistura de aminoácidos, vitaminas, sais minerais e hormônios, aumenta consideravelmente a proliferação celular e o tamanho do fígado em animais sadios, com fibrose e com cirrose. Nestes dois últimos, além do crescimento hepático, ocorre também uma importante redução na quantidade de colágeno, significando uma melhora morfológica que, por muitas vezes, resulta em uma melhora funcional. Sendo assim, o objetivo do presente trabalho foi o verificar se o uso de fatores hepatotróficos nutricionais traria também uma melhora morfológica e funcional em animais com cirrose induzida por tiocetamida após uma ressecção hepática de 40%. Utilizou-se 40 ratos (Rattus norvegicus) Wistar fêmeas cuja indução da cirrose foi pela administração intraperitoneal de tiocetamida. Ao final deste período, e após 10 dias de descanso, todos os animais foram submetidos a uma hepatectomia parcial (HP) de 40%. Foram então divididos em dois grupos: um que recebeu intraperitonealmente a solução de fatores hepatotróficos nutricionais durante 12 dias, designado grupo HP+FHN, e outro que recebeu solução fisiológica nas mesmas condições, formando o grupo HP+S. Os seguintes parâmetros foram avaliados no término do período experimental: dados biométricos (peso do fígado, IHS: índice hepassomático e IHC: índice hepatocarcaça), bioquímica hepática plasmática (AST, ALT, fosfatase alcalina, bilirrubina total e albumina), quantificação da densidade volumétrica de colágeno hepático por morfometria, quantificação do índice de proliferação celular por imunohistoquímica para PCNA e expressão de genes pró-fibróticos (MMP2, TIMP1, Cola1 e TGFb1) por PCR em tempo real. De fato, os fígados dos animais do grupo HP+FHN estavam maiores do que os animais do grupo HP+S (aumentos de 8,4%, 5,6% e 8,4% no peso do fígado, IHS e IHC respectivamente), e também apresentaram maior índice de proliferação de hepatócitos (44,9%). Ocorreu também redução de 27,9% na densidade volumétrica do colágeno hepático no grupo que recebeu FHN comparandose com o grupo que recebeu solução salina. Esta redução também foi observada na expressão do gene de colágeno a1, que foi de 53%. Porém, não houve diferença nos demais genes avaliados. Dentre os parâmetros bioquímicos, apenas a fosfatase alcalina mostrou redução. Os resultados obtidos permitem concluir que o uso de FHN acarreta em um aumento da regeneração hepática acompanhado de uma redução da quantidade de colágeno e, esses achados, em conjunto, podem representar uma condição benéfica na recuperação de pacientes com cirrose submetidos à ressecção hepática / The current study evaluated the role of parenteral solution of nutritional hepatotrophic factors in animals with cirrhosis undergoing partial hepatectomy. This procedure is fearful in these animals due to the possibility of acute liver failure, since removal of a liver fragment further reduces the functional capacity of an already compromised organ. Moreover, it is known that cirrhotic liver decreases its regenerative capacity, which impairs the recovery of the animal, and also regenerates cirrhotic. These factors, together, contribute to a considerable rate of postoperative mortality. However, there are some situations when these patients need to be submitted to liver resection, such as trauma, infections and neoplasm. In fact, the presence of hepatocellular carcinoma represents the most important indication of this procedure in patients with cirrhosis. On the other hand, it has been shown that parenteral administration of a solution of the nutritional hepatotrophic factors (NHF), a mixture of amino acids, vitamins, minerals and hormones, significantly increases cell proliferation and liver size in healthy, fibrotic and cirrhotic animals. In the two latter, beyond the liver growth, there is also a significant reduction in the amount of collagen, meaning a morphological enhancement, resulting in a functional improvement. Therefore, the objective of this study was to determine whether the use of nutritional hepatotrophic factors would also lead a morphological and functional improvement in animals with thioacetamide-induced cirrhosis after 40% liver resection. We used 40 rats (Rattus norvegicus) female Wistar whose cirrhosis was induced by intraperitoneal administration thioacetamide. At the end of this period, and after 10 days of rest, all animals were underwent a partial hepatectomy (PH) of 40%. They were then divided into two groups: one that received intraperitoneally a solution of nutritional hepatotrophic factors for 12 days, designated PH+NHF group, and another that received saline under the same conditions, forming the PH+S group. The following parameters were evaluated at the end of the trial period: biometrics (liver weight, HSI hepatossomatic index, and HCI hepatocarcass index), plasmatic liver biochemistry (AST, ALT, alkaline phosphatase, total bilirubin and albumin), quantification of volume density of collagen in liver morphology, quantification of cell proliferation by immunohistochemistry for PCNA and expression of pro-fibrotic genes (MMP2, TIMP1, TGF1 and Cola1) by real-time PCR. In fact, the livers of animals in group PH+NHF were larger than the animals in PH+S group (increases of 8.4%, 5.6% and 8.4% in liver weight, HSI and HCI, respectively), and also had higher rates of proliferation of hepatocytes (44.9%). There was also a 27.9% reduction in liver volume density of collagen in the group receiving NHF compared with the group that received saline. This reduction was also observed in gene expression of collagen a1, which was 53%. However, there were no differences in other genes evaluated. Among biochemical parameters, only the alkaline phosphatase showed a reduction. The results indicate that the use of NHF leads to an increase in liver regeneration accompanied by a reduction in the amount of collagen, and these findings, together, can represent a beneficial condition in the recovery of patients with cirrhosis undergoing liver resection

<p>Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage damage and loss in the joints that affects approximately 27 million adults in the US. Tissue that is damaged by OA is a major health concern since cartilage tissue has a limited ability to self-repair due to the lack of vasculature in cartilage and low cell content. Tissue engineering efforts aim towards the development of cartilage repair strategies that mimic articular cartilage and are able to halt the progression of the disease as well as restore cartilage to its normal function.</p><p>This study harnesses the biological activity of collagen type II, present in articular cartilage, and the superior mechanical properties of collagen type I by characterizing gels made of collagen type I and II blends (1:0, 3:1, 1:1, 1:3, and 0:1). The collagen blend hydrogels were able to incorporate both types of collagen and retain chondroitin sulfate (CS) and hyaluronic acid (HA). Cryoscanning electron microscopy images showed that the 3:1 ratio of collagen type I to type II gels had a lower void space percentage (36.4%) than the 1:1 gels (46.5%) and the complex modulus was larger for the 3:1 gels (G*=5.0 Pa) compared to the 1:1 gels (G*=1.2 Pa). The 3:1 blend consistently formed gels with superior mechanical properties compared to the other blends and has the potential to be implemented as a scaffold for articular cartilage engineering.</p> <p>Following the work done to characterize the collagen scaffolds, we studied whether an aggrecan mimic, CS-GAHb, composed of CS and HA binding peptides, GAH, and not its separate components, is able to prevent glycosaminoglycan (GAG) and collagen release when incorporated into chondrocyte-embedded collagen gels. Bovine chondrocytes were cultured and embedded in collagen type I scaffolds with CS, GAH, CS and GAH, or CS-GAHb molecules. Gels composed of 3:1 collagen type I and II with CS or CS-GAHb were also studied. The results obtained showed CS-GAHb is able to decrease GAG and collagen release and increase GAG retention in the gels. CS-GAHb also stimulated cytokine production during the initial days of scaffold culture. However, the addition of CS-GAHb into the chondrocyte-embedded collagen scaffolds did not affect ECM protein expression in the gels. The incorporation of collagen type II into the collagen type I scaffolds did not significantly affect GAG and cytokine production and ECM protein synthesis, but did increase collagen release. The results suggest the complex interaction between CS-GAHb, the chondrocytes, and the gel matrix make these scaffolds promising constructs for articular cartilage repair.</p> <p>Finally, we used Dunkin Hartley guinea pigs, a commonly used animal model of osteoarthritis, to determine if high frequency ultrasound can ensure intra-articular injections of the aggrecan mimic are accurately positioned in the knee joint. A high-resolution small animal ultrasound system with a 40 MHz transducer was used for image-guided injections. We assessed our ability to visualize important anatomical landmarks, the needle, and anatomical changes due to the injection. From the ultrasound images, we were able to visualize clearly the movement of anatomical landmarks in 75% of the injections. The majority of these showed separation of the fat pad (67.1%), suggesting the injections were correctly delivered in the joint space. The results demonstrate this image-guided technique can be used to visualize the location of an intra-articular injection in the joints of guinea pigs and we are able to effectively inject the aggrecan mimic into knee joints.</p><p>All of the work presented here suggests that the addition of the aggrecan mimic to collagen I and collagen I and II scaffolds has shown that this type of construct could be useful for treating cartilage damage in the future.</p>