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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

High fat diet has sexually dimorphic effects on body composition, adiposity and glucose homeostasis in Poly(A)-binding protein 4 (Pabp4) knockout mice

Scanlon, Jessica Patricia January 2017 (has links)
Obesity can lead to a range of health problems including type 2 diabetes (T2DM), cardiovascular disease and non-alcoholic fatty liver disease (NAFLD), and causes an estimated 2.8 million deaths annually (2016). It is a growing epidemic affecting over 600 million people worldwide (in 2014), with 26.8% of the adult population in England alone being obese, an increase of 10% in the last decade, and 62.9% overweight or obese. This trend is predicted to continue, and is attributed to an increasingly sedentary lifestyle, coupled with a high calorie “western diet”, which is estimated to cost >£25billion/year in the UK (2015), which is predicted to rise to £49.9 billion by 2050. It is clear that both sex and genetics affect the extent to which individuals exposed to a high fat diet develop adiposity and its associated morbidities, although the mechanisms underlying these differences are not well understood. Here we explore this aetiology, focusing on poly(A)-binding protein 4 (PABP4), an RNA-binding protein in which polymorphisms associated with altered cholesterol levels and cardiovascular disease risk were identified in human GWAS studies. To this end, I take advantage of an unpublished Pabp4 knock-out mouse, maintained on either normal (ND) or high fat diet (HFD), to explore the role of PABP4 in determining the response to high fat diet. PABP4 is a poorly characterised member of the PABP family, which are multifunctional central regulators of global and mRNA-specific translation, and stability. In cell lines, PABP4 is predominantly cytoplasmic, consistent with such functions. However, analogously to PABP1, the prototypical PABP family member, PABP4 is relocalised to stress granules or the nucleus in response to specific cellular stresses and/or viral infections, suggesting a role in altering gene expression programs in responses to changing cellular conditions. Whilst the expression pattern of PABP4 within tissues has not been previously characterised, western blotting of adult mouse tissues revealed that PABP4 is highly expressed in tissues relevant to obesity, T2DM and NAFLD, such as adipose, pancreas, liver and muscle, consistent with the idea that it may play a role in regulating gene expression programs in response to HFD. Immunohistochemistry of tissue sections provided additional insight, revealing a distinct cellular distribution of PABP4 in some tissues, when compared to the well characterised PABP1. Birth weight and post-birth growth can affect adult metabolism. In particular, low birth weight and catch-up growth, characterised by preferentially putting down adipose over lean mass, increases the risk of metabolic conditions in adulthood, such as obesity, T2DM and cardiovascular disease. Therefore, Pabp4-/- and wildtype mice were weighed at birth and daily until weaning. Interestingly this revealed that Pabp4-/- mice have a reduced weight at birth that is exacerbated to weaning (21days (P21)) (5.7% and 18.3% reductions respectively). This analysis also uncovered a reduced survival to weaning, with both male and female Pabp4-/- mice being present at sub-Mendelian ratios by P21 (p=0.0056). Whilst most death occurred neonatally, Pabp4-/- mice showed an increased rate of attrition until weaning, preceded in some cases by an arrest of weight gain. Weight gain was also tracked from 4 weeks to 12 weeks of age on normal diet showing that Pabp4-/- mice had reduced weight into adulthood (12% reduction at 12wks). Analysis of weight gain by sex uncovered a sexually dimorphic effect of Pabp4-deficiency, with female, but not male, Pabp4-/- mice remaining reduced in weight compared to wildtype after 8 weeks on ND (13.4% reduction in female weight). Body composition analysis showed that fat mass was equivalent to wildtype at 12 weeks of age in both sexes but that female Pabp4-/- mice had a 14.3% reduction in lean mass. Neither the catch-up growth in males nor the reduced lean mass in females was sufficient to result in a change in glucose homeostasis. As the risk of developing metabolic disorders in adult life is a consequence of both genetic and environmental factors, such as diet, Pabp4-/- were placed on a HFD at 4 weeks of age for 8 weeks. HFD models the ‘western’ diet, and has been shown to induce obesity, insulin resistance and glucose intolerance in wildtype mice. Whereas Pabp4-/- mice were only distinguishable from wild-type in terms of female lean mass on normal diet, pronounced sexually dimorphic differences were observed in HFD fed mice. Male Pabp4-/- mice appeared to be partially protected from the negative effects of an 8 week HFD regimen, with a 44% decrease in adipose mass gain compared to wildtype despite equal lean mass. Pabp4-/- male mice also had significantly reduced ectopic lipid stores, with an 81% decrease in hepatic triglyceride concentration compared to wildtype, meaning that NAFLD has not developed. Furthermore, Pabp4- /- male mice did not develop hyperinsulinemia on HFD and retained insulin sensitisation (assessed via glucose tolerance test (GTT) and insulin tolerance test (ITT)), although they displayed wildtype-like elevated plasma glucose concentrations (compared to ND). Western blotting had detected high PABP4 levels in the pancreas, indicating a possible pancreatic origin of these alterations. However, immunofluorescence revealed that PABP4 was confined to the exocrine portion of the pancreas, and was undetectable in the insulin producing pancreatic beta cells, suggesting this phenotype may not be beta cell in origin. This is consistent with the fact that the Pabp4-/- male mice retained an appropriate glucose-induced burst of insulin secretion, and therefore insulin production appears unimpaired. Thus, the primary defect may reside in the exocrine pancreas, which aids digestion, or in other key metabolism related tissues (e.g. muscle, liver, adipose and brain), or a combination thereof. In HFD fed wildtype mice, insulin resistance is caused by increased adiposity and ectopic lipid depots, which blunt insulin stimulated signalling cascades, meaning that the normal responses to insulin (e.g. cellular up take of glucose in muscle and arrested glucose production in liver, to decrease plasma glucose concentrations), are impaired. Therefore, the absence of insulin resistance in HFD fed Pabp4-/- male mice may be a consequence of the reduced increase in adipose mass and ectopic lipid deposits detected in these mice, and their consequent lack of inhibition on insulin signalling pathways. The reduced adiposity was not a result of reduced food intake or dietary fat absorption as male Pabp4-/- mice did not eat less nor exhibit apparent steatorrhea (fatty stools). These results highlight that the Pabp4-/- male mice appear to have an alteration in energy use/storage, and the investigation of this will form the basis of future work. When fed HFD, female Pabp4-/- mice revealed a divergent phenotype to that of wildtype female mice and Pabp4-/- male mice. HFD fed Pabp4-/- female mice showed no difference to HFD-fed wildtype mice in terms of weight, but still exhibited the reduction in lean mass seen on ND, but now with a 22.8% increase in volume of adipose tissue. Together, this means that HFD fed Pabp4-/- females have a higher body fat percentage (32.6% compared to 25.9 % for wildtype females). In contrast to the males, there was no difference in terms of hepatic triglycerides in HFD fed Pabp4-/- female mice and they showed greater hyperglycaemia than wildtype (GTT), although like males they retained insulin sensitisation (ITT). These potentially conflicting results in terms of insulin sensitivity and plasma glucose concentrations may result from the alterations in body composition, which can confound results when lean mass is altered and total body weight is used for calculating doses for GTT/ITT. Interestingly, adiponectin, an adipokine normally found in inverse proportion to adipose mass, was increased in plasma from HFD fed Pabp4-/- female mice (21% increase from HFD fed wildtype mice). Whilst surprising given the increase fat mass of Pabp4-/- females, the insulin sensitising properties of adiponectin may help to explain the retained insulin sensitivity detected in the female Pabp4-/- mice. / The finding that HFD revealed metabolic differences in the Pabp4-/- mice lead to the question of whether Pabp4-/- mice have issues adapting to other situations which require modulation of energy storage and glucose homeostasis. One such event is pregnancy, when maternal regulation of insulin resistance is tightly modulated throughout gestation. We therefore characterised the maternal Pabp4-/- environment in late pregnancy (E18.5), when insulin sensitivity decreases to 40-60% lower than pre-pregnancy which results reduced maternal glucose uptake, freeing the glucose up for the rapidly developing foetus. Pregnant Pabp4-/- mice had elevated plasma insulin concentration post fasting (63.7% increase), however glucose homeostasis was wildtype-like, both in terms of plasma glucose and insulin concentrations, throughout a GTT. However, plasma glucose and insulin concentrations in E18.5 Pabp4-/- foetuses were significantly decreased (9% and 44.3% respectively). Pabp4-/- foetuses also had reduced foetal and placental weight/length parameters. This establishes that the differences in weight observed at birth were present by late gestation and secondly, that the reductions in both foetal glucose and insulin concentrations which may contribute to or underlie the reduced growth. It also suggests that the differences seen in adulthood on HFD may be a consequence of metabolic differences present during pregnancy. Taken together, these data support the hypothesis that PABP4 plays a key role in the regulation of mRNAs which are important in growth, post-natal survival and metabolic adaption to high fat diet.
82

Investigating gene expression patterns in the mammalian cardiovascular system

Tsang, Hiu-Gwen January 2018 (has links)
The cardiovascular system is an essential component of mammalian biology. It is a complex network of various tissues and structures with unique functions. The function of the cardiovascular system is to supply nutrients including oxygen to the various cells, tissues and organs within the body, and remove waste products from them. Given the importance of this role, it is not surprising that there are countless regulatory mechanisms at the molecular, cellular and tissue levels that are required to support this functional system. Perturbations in parts of this system are likely to lead to abnormalities, and thus give rise to cardiovascular-related diseases. Despite the currently expanding list of genes reported to be involved in a variety of cardiovascular-related diseases, including calcific aortic valve disease (CAVD), the functions and associated pathways of these factors in both normal and pathological physiology have yet to be fully understood, such as at the transcriptomic level. In this thesis, a genome-wide transcriptomic atlas of the healthy mammalian cardiovascular system was generated using the sheep as a large animal model. This atlas was generated using RNA-seq, with the aim of further understanding normal gene expression patterns in the context of the known physiology of healthy mammalian tissues. Through this work, I identified novel gene networks and detailed functional clustering of co-expressed genes with region-specific expression and specialised cardiovascular roles. One interesting cluster was highly expressed in the cardiac valves, and shared genes found in physiological bone development, such as bone morphogenetic protein 4 (BMP4), collagen type I alpha 2 (COL1A2), Sry homeobox 8 (SOX8) and bone gamma-carboxyglutamate protein (BGLAP), some of which have been implicated in vascular calcification. Further to this work, I studied the expression profiles of these key cardiovascular genes during development in the sheep from foetal to adult stages. In addition, I investigated the gene expression patterns of various key vascular calcification genes. These studies showed differential expression of genes in the different cardiovascular tissues, demonstrating transcriptional differences between these different tissues known to have different functions. CAVD involves progressive valve leaflet thickening and severe calcification, resulting in impaired leaflet motion. The in vitro calcification of primary rat, human, porcine and bovine aortic valve interstitial cells (VICs) is commonly employed to examine the mechanisms of CAVD. However, to date, no published studies have utilised cell lines to investigate this process Thus, in this project, I generated and evaluated the calcification potential of an immortalised cell line derived from sheep aortic VICs (SAVICs). This novel large animal in vitro model of CAVD was demonstrated to calcify under high calcium and phosphate conditions. Changes in the expression of key calcification genes during VIC calcification was also observed, including increased mRNA expression of bone markers Runt-related transcription factor 2 (RUNX2) and sodium-dependent phosphate transporter 1 (PiT1), and a concomitant decrease in matrix Gla protein (MGP) mRNA expression. In addition, the role of extracellular nucleotides and their receptors (P2 receptors), which have been previously shown to be important in bone and vascular calcification, were investigated using SAVICs in vitro. This study has shown that extracellular nucleotides, particularly adenosine 5’-triphosphate (ATP) and uridine 5’-triphosphate (UTP) and other agonists of P2 receptors, reduced VIC calcification in vitro. Moreover, the cutting-edge gene-editing technology, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9), was successfully applied to generate large animal models of cardiovascular-related diseases. In this project, I applied the CRISPR/Cas9 technology to edit ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and fibrillin 1 (FBN1) to generate two models of vascular calcification and Marfan Syndrome (MFS), respectively. In the ENPP1-edited animals, soft tissue calcification has been observed in the biallelic mutant and homozygous pigs. In this project, I have developed a range of novel in vitro and in vivo tools to advance the study of cardiovascular disease. These studies demonstrate that large animal models are highly valuable in the field of cardiovascular biology. The in vivo and in vitro experimental models described should facilitate detailed analysis of cardiovascular molecular biology and ultimately lead to therapies which will minimise the morbidity and mortality currently arising from cardiovascular pathology.
83

Contributions au développement de modèles petit animal et cellulaire pour les études de pathogenèse des morbillivirus / Contributions to the development of a small animal and a cell model for morbillivirus pathogenesis studies

Comerlato, Juliana 16 November 2016 (has links)
Morbillivirus est un genre de virus à ARN simple brin de polarité négative de la famille des Paramyxoviridae. Actuellement, il est composé de sept espèces responsables de maladies hautement contagieuses. Les infections par morbillivirus causent une forte mortalité chez l’Homme, les petits ruminants, les carnivores et chez certains mammifères marins. Les vaccins disponibles contre les morbillivirus exigent généralement 7-10 jours pour développer une immunité protectrice. Après la Peste Bovine, première maladie animale éradiquée avec succès, la peste des petits ruminants (PPR) est la prochaine cible pour l'éradication au niveau mondial d’ici 2030. Le vaccin actuel basé sur la souche PPR Nigeria 75/1 est adéquat pour la campagne d'éradication. Cependant, certaines améliorations peuvent être envisagées pour accroître son efficacité, raccourcir le temps nécessaire pour l’éradication et réduire les coûts. Par exemple, l’introduction d’un vaccin marqué positif/négatif permettrait la différenciation entre animaux infectés et vaccinés (DIVA stratégie), permettant ainsi en temps réel la surveillance de l'infection, la vaccination et l’élimination rapide des animaux infectés. Une autre amélioration pourrait être la modification du vaccin actuel par génétique inverse pour insérer une cassette exprimant des ARN interférents capables de cibler les souches virulentes PPRV. Ce vaccin thérapeutique serait utile en situation d'urgence pour contrôler l’infection le temps que l’immunité protectrice se mette en place après vaccination. Afin de développer et tester ces nouveaux vaccins et outils thérapeutiques, il est nécessaire d’utiliser des modèles petit animal et cellulaire pour limiter les expérimentations avec les animaux d'élevage Dans ce travail, nous avons contribué au développement d’un modèle cellulaire in vitro et d’un modèle murin in vivo pour étudier la pathogenèse des morbillivirus. Le présent document est divisé en trois principaux chapitres : « Identification d’un modèle cellulaire pour les études de pathogenèse du PPRV » ; « Construction d’un clone PPR marqué le gène luciférase rapporteur » ; et « Évaluation in vivo d’un petit ARN interférent (siRNA) contre les morbillivirus ». Dans le premier chapitre, la ligne cellulaire murine 10T1/2 a été éprouvée avec des souches atténuées et virulentes du PPRV dans des conditions différentes d’expression du récepteur SLAM de la chèvre et de la réponse interféron type I. Les résultats ont montré une permissivité des cellules 10T1/2 limitée aux souches virulentes du PPRV, laquelle est indépendante du récepteur SLAM de la chèvre et de la réponse interféron type I. Le deuxième chapitre visait à développer un PPRV recombinant capable d’exprimer une luciférase par la génétique inverse. Diverses stratégies d’assemblage du génome entier du PPRV ont été établies pour l’obtention du clone d’ADNc avec le génome complet du PPRV. Cependant, le rescue a été impossible à réaliser et les raisons en sont discutées. Le dernier chapitre englobait l’évaluation des siRNA comme outils thérapeutiques contre un autre morbillivirus recombinant capable d’exprimer la luciférase, le virus de la rougeole (MV). Alors que sur les lignées cellulaires nous avons observé 100% d’activité antivirale des siRNA contre le rMV-luc, la validation in vivo, utilisant le modèle souris transgénique CD46 humain sensible à la rougeole, a échoué. Pour conclure, ce travail apporte des avancées sur le développement d’outils pour étudier la pathogenèse non seulement du PPRV mais aussi d’autres morbillivirus. / Morbillivirus genus, a non-segmented negative single-strand RNA (ssRNA) group of viruses, belongs to the Paramyxoviridae family and is currently composed of seven species responsible to highly contagious diseases. Morbillivirus infections cause significant mortality in humans, small ruminants, carnivores and in some marine mammals. The available vaccines against morbillivirus infections require usually 7-10 days to induce a protective immunity. After Rinderpest, the first animal disease successfully eradicated, peste des petits ruminants (PPR) is the next target for global eradication by 2030.The current vaccine based on the Nigeria 75/1 is fit for purpose for the eradication campaign. However, some improvements can be envisaged to increase efficacy, shorten the time to complete the eradication and reduce costs. For instance, the introduction of a positive/negative marker in the vaccine could allow the Discrimination between Infected and Vaccinated Animals (DIVA strategy), thus enabling the real-time parallel monitoring of infection and vaccination, and rapid elimination of infected animals. Another improvement could be the modification of the current vaccine by reverse genetics to insert a cassette expressing interfering RNA targeting virulent strains of PPR. This therapeutic vaccine would be useful in emergency situations to control the infection over the delay necessary for the acquisition of an efficient vaccine protection. In order to develop and test these new vaccine tools, there is a need for new cell or small animal models to limit experiments with farm animals. In this work, we contributed in the development of in vitro and in vivo murine models to study morbillivirus pathogenesis. The present document is divided in three main chapters: “Identification of a cell model to PPRV pathogenesis studies”; “Construction of a full-length cDNA clone of PPRV with a luciferase reporter gene” and “In vivo evaluation of small interfering RNA (siRNA) against morbilliviruses”. In the first chapter the mouse cell line 10T1/2 was challenged with attenuated and wild type PPRV strains using different conditions of goat SLAM expression and type I IFN response. The results showed a restricted permissiveness of 10T1/2 to wild type PPRV, which was independent of goat SLAM receptor and type I IFN response. The second chapter aimed to develop a recombinant PPRV expressing luciferase through reverse genetics methodology. Various strategies to assembling the PPRV genome were established reaching up to the full-length cDNA PPRV-luciferase construction. However, the rescue could not be achieved and the reasons for that are discussed. The last chapter encompassed the evaluation of siRNA as a prophylactic tool against another luciferase recombinant morbillivirus, the measles virus. In vitro and in vivo studies were performed with the recombinant MV (rMV-luc). Whereas in cell lines siRNA showed 100% of antiviral activity against rMV-luc, the validation in vivo, using a human CD46 transgenic mouse model susceptible to measles, failed. In conclusion, this work provides advancements in the development of tools for the study of the pathogenesis of PPRV and other morbilliviruses.
84

Efeitos do óleo da semente do maracujá na psorí­ase experimental / Effects of passion fruit seed oil on experimental psoriasis

Ana Carolina Miguel Alvarenga 11 June 2018 (has links)
A psoríase é uma doença de pele inflamatória crônica, que afeta cerca de 2-4% da população mundial. Se desenvolve ao longo do tempo, principalmente no final da adolescência ou início da idade adulta e depende de uma complexa interação entre fatores genéticos e ambientais. Dados experimentais demostram que a dermatite induzida por imiquimode (IMQ) em camundongos assemelha-se estreitamente às lesões de psoríase humana, tanto nas características fenotípicas e histológicas como no desenvolvimento das lesões na epiderme. O estudo avaliou os efeitos anti-inflamatórios do óleo de semente de maracujá (Passiflora edulis) no tratamento da psoríase, utilizando a análise histológica e imunológica da epiderme. O experimento foi realizado com 36 camundongos Balb/c, os quais foram submetidos à indução da psoríase por imiquimode, por 10 dias consecutivos. O tratamento foi realizado com óleo de semente de maracujá in natura 100%, pomada LECIGEL® 2%, pomada associação de óleo de semente de maracujá 20% e LECIGEL® 2%, por 15 dias. Tanto o óleo da semente do maracujá quanto a associação do mesmo ao LECIGEL® diminuíram o quadro inflamatório induzido por imiquimode nas orelhas tratadas. Através das análises imuno-histoquímicas realizadas na epiderme (PCNA, IL-6, VEGF, CD34), observou-se um aumento na formação de corpos apoptóticos, diminuição a hiperplasia epitelial e redução do infiltrado inflamatório. Os resultados deste experimento demonstraram que o óleo da semente do maracujá desempenha um efeito anti-inflamatório no tratamento da psoríase induzida por imiquimode. / Psoriasis is a chronic inflammatory skin disease that affects about 2-4% of the world\'s population. It develops over time, especially in late adolescence or early adulthood and depends on a complex interaction between genetic and environmental factors. Experimental data show that imiquimode-induced dermatitis (IMQ) in mice closely resembles human psoriasis lesions, both in phenotypic and histological characteristics and in the development of lesions in the epidermis. The study evaluated the anti-inflammatory effects of passion fruit (Passiflora edulis) oil in the treatment of psoriasis, using the histological and immunological analysis of the epidermis. The experiment was performed with 36 Balb / c mice, which were submitted to psoriasis induction by imiquimode, for 10 consecutive days. The treatment was carried out with 100% fresh passion fruit seed oil, LECIGEL ® 2% ointment, 20% passion fruit seed oil ointment and LECIGEL ® 2% for 15 days. Both passionflower seed oil and its association with LECIGEL ® decreased the imiquimod-induced inflammation in the treated ears. Through the immunohistochemical analyzes performed on the epidermis (PCNA, IL-6, VEGF, CD34), an increase in the formation of apoptotic bodies, decrease in epithelial hyperplasia and reduction of inflammatory infiltrate was observed. The results of this experiment suggest that passion fruit seed oil has an anti-inflammatory effect in the treatment of imiquimode-induced psoriasis.
85

Análise histológica e histomorfométrica da osseointegração de implantes de titânio inseridos na tíbia de ratos Wistar induzidos por ácido zoledrônico e dexametasona / Histologic and histomorphometric analysis of the osseointegration of endosseous implants placed on the tibiae of Wistar rats treated with zoledronic acid and dexamethasone

Marcio Augusto de Oliveira 03 December 2012 (has links)
A terapia com bisfosfonatos tem sido frequentemente empregada no tratamento de doenças metabólicas do osso e neoplasias malignas. O objetivo deste estudo foi avaliar através de análise histológica e histomorfométrica em cortes não descalcificados, a influência dos bisfosfonatos nitrogenados endovenosos associados ou não a dexametasona sobre a osseointegração de implantes instalados em tíbias de 27 ratos Wistar. Ácido zoledrônico e dexametasona foram administrados por via subcutânea nos animais dos grupos experimentais. Os animais foram acompanhados por 7, 14 e 28 dias. Nossos resultados mostraram que não houve falha na osseointegração em nenhum animal avaliado e que não foram observadas diferenças estatisticamente significantes entre os 3 grupos com relação à quantidade de contato entre osso e implante e presença de osso em áreas pré determinadas, nos tempos observados. No entanto nossas observações histológicas revelaram que nos animais tratados com bisfosfonatos associados ou não com dexametasona, aos 14 e 28 dias após a colocação do implante não ocorreu o fenômeno de remodelação da cortical óssea, ao contrário do grupo controle. Concluímos que a terapia com bisfosfonatos associada ou não com dexametasona não impediu a osseointegração do implante com o osso mas inibiu severamente a remodelação da cortical óssea pré existente. / Bisphosphonate therapy has been often employed in the treatment of metabolic bone diseases and malignancies. The aim of this study was to evaluate through histological and histomorphometric analysis the influence of intravenous nitrogen-containing bisphosphonates alone or combined with dexamethasone on the osseointegration of implants placed in the tibia of 27 male Wistar rats in non decalcified samples. Zoledronic acid and dexamethasone were administered through sub cutaneous injections. The animals were followed through 7, 14, and 28 days. Our results showed that there was no failure in osseointegration in any animal, and that there were no statistically significant differences among the 3 groups regarding the amount of bone-implant contact and peri-implant bone density in predetermined areas. However our histological observations revealed that animals treated with bisphosphonates, associated or not with dexamethasone, at 14 and 28 days after implant placement has not occurred the phenomenon of cortical bone remodeling, unlike control group. We conclude that bisphosphonate therapy associated or not with dexamethasone did not prevent osseointegration of the implants but severely inhibited the remodeling of pre-existing cortical bone.
86

Caracterização fenotípica e análise do sistema nervoso central dos camundongos mutantes equilíbrio e mergulhador induzidos pelo agente mutagênico n-ethyl-n-nitrosourea / Phenotypical characterization and central nervous system analysis of mutants equilíbrio and mergulhador induced by mutagenic agent n-ethyl-n-nitrosourea

Marianna Manes 08 December 2017 (has links)
O agente mutagênico N-ethyl-N-nitrosourea (ENU) é amplamente utilizado para produzir novas mutações em camundongos, dando origem aos mutantes recessivos equilíbrio (eqlb), que possui uma mutação pontual no gene NADPH oxidase 3 (Nox3), cromossomo 17 e mergulhador (mlh), no gene Otopetrin 1 (Otop1), cromossomo 5; sendo que ambos apresentam alterações vestibulares. Devido à semelhança da função do aparelho vestibular humano e do camundongo, a análise comportamental desses modelos pode ser uma valiosa contribuição para identificar alterações no controle do equilíbrio e do movimento. Deste modo, com o objetivo caracterizar o comportamento dos mutantes eqlb e mlh foram realizados os seguintes testes: avaliação da atividade geral por observação direta no campo aberto, coordenação motora na trave elevada, labirinto em cruz elevada (LCE), para avaliar o comportamento do tipo ansioso, labirinto em T e reconhecimento de objetos para avaliar a memória, além do teste de suspensão pela cauda para verificar o comportamento do tipo depressivo. Os resultados mostraram que em comparação aos camundongos BALB/c, os mutantes eqlb e mlh apresentaram redução do reflexo auricular, reflexo de endireitamento, resposta ao toque, na locomoção e na frequência de levantar. A redução do reflexo auricular, da resposta ao toque e do redução do reflexo de endireitamento mostrou um possível prejuízo do sistema psicomotor. A redução da frequência de levantar provavelmente foi consequência da dificuldade motora dos camundongos mutantes. Os resultados do teste da trave elevada indicaram que os mutantes eqlb e mlh apresentaram um prejuízo motor principalmente relacionado à coordenação motora. O tempo de imobilidade aumentado no teste de suspensão pela cauda e a incapacidade de nadar em camundongos eqlb e mlh reforçaram o papel do sistema vestibular na manutenção da percepção de gravidade, movimento e equilíbrio. / The mutagenic agent N-ethyl-N-nitrosourea (ENU) is widely used to produce new mutations in mice, giving origin to the equilíbrio (eqlb) which has a mutation in the NADPH oxidase 3 (Nox3) gene, chromosome 17 and mergulhador (mlh) in the gene Otopetrin 1 (Otop1), chromosome 5; both mutant strain showed vestibular impairment. Due to the similarity of the vestibular apparatus between human and mouse, the behavioral analysis of the mutant can be a valuable contribution to identify alterations involved in the control of balance and movement. This study aimed to characterize the behavior of eqlb and mlh mutant mice using the following behavioral tests: evaluation of the general activity by direct observation in the open field, motor coordination in the balance beam, elevated plus maze to evaluate the behavior of the anxious type, T-maze and recognition of objects to evaluate memory. In addition, tail suspension test was used to verify depressive like behavior. The results showed that in relation to the BALB/c mice, the mutants eqlb and mlh showed reduction of auricular reflex, surface-righting reflex, touch response, locomotion and rearing frequency. The reduction of the auricular reflex and the touch response pointed to the impairment of the psychomotor system, and the reduction of the surface-righting reflex showed a possible impairment of the psychomotor system. The reduction in the rearing frequency was, probably, a consequence of the motor impairment observed in the mutant strains. The results of the elevated plus maze test indicated that the mutants eqlb and mlh showed motor impairment mainly related to motor coordination. The increased immobility time in the tail suspension test and the inability to swim in eqlb and mlh mice reinforced the role of the vestibular system in maintaining the perception of gravity, movement, and balance.
87

Controle de estímulos e respostas ao estresse no modelo de recaída ao álcool \"cue-induced / Stimulus control and stress responses in the cue-induced model

Fernanda Libardi Galesi 22 April 2014 (has links)
O modelo de recaída cue-induced é comumente utilizado para o estudo da recaída ao uso de drogas causada pela exposição dos animais à estímulos ambientais previamente associados à droga. Quando o álcool é a droga a ser estudada, um estímulo contextual (S) e um reforçador condicionado (Sr) são os estímulo frequentemente associados ao seu consumo. Embora esse modelo seja consolidado na área, sua validade de constructo vem sendo criticada; entre essas críticas estão o fato de que apenas o Sr adquire controle sobre a resposta de procura pela droga, além de que pouco se sabe sobre os sistemas neurais envolvidos nessa recaída. Portanto, este trabalho teve como objetivo principal avaliar o papel dos processos operantes no procedimento do modelo de recaída ao uso de álcool cue-induced, além de avaliar a participação de sistemas neurais ligados ao estresse nessa recaída. Ainda, este trabalho teve como objetivo melhorar o procedimento desse modelo animal. Os experimentos apresentados no Capítulo 1 tiveram como objetivo melhorar o controle exercido por S sobre a recaída, aprimorando o modelo, além de avaliar processos de aprendizagem associativa que ocorrem nesse modelo. Dois experimentos foram realizados para atingir esses objetivos. No primeiro, dois grupos de ratos foram treinados no modelo cue-induced, porém um grupo foi treinado sob o esquema de razão fixa 1 (FR1) e o outro sob o esquema de razão variável 5 (VR5). No segundo experimento, os ratos foram treinados nesse modelo, porém os estímulos S e Sr foram apresentados separadamente na fase de treino. Os resultados desses experimentos indicaram que o treino separado foi eficaz em melhorar o controle de S sobre a recaída e que a troca de esquema de reforço não foi eficaz para aumentar esse controle. Os resultados também mostraram que quando os estímulo são treinados em conjunto o Sr sombreia o S e quando eles são treinados separadamente e testados como um composto ocorre somação. Os experimentos apresentados no Capítulo 2 tiveram o objetivo de avaliar se eixos neurais ligados à resposta ao estresse estariam envolvidos na recaída mimetizada pelo modelo cue-induced. Ratos Marchigian Sardinian Preferring (msP) e Wistars foram treinados no modelo cue-induced e, na fase de testes, Antalarmin, Metirapona e corticosterona (CORT) foram injetados i.p. nos animais. Os resultados mostraram que o Antalarmin (dose 20 mg/kg) bloqueou a recaída em ambas as cepas, que a Metirapona (doses 50 mg/kg e 100 mg/kg) bloqueou a recaída nos ratos msP e apenas a dose de 100 mg/kg bloqueou a recaída nos ratos Wistars e que a CORT não teve efeito na em nenhuma das cepas. Esses resultados mostraram o procedimento do modelo de recaída cue-induced pode ser aprimorado principalmente no que tange ao controle do S sobre a recaída. Os resultados também mostraram que respostas ao estresse influenciam a recaída observada nesse modelo / The cue-induced relapse model is a model commonly used to study relapse caused by environmental stimuli. In its procedure, the environmental stimuli are usually a contextual stimulus (S) and a conditioned reinforcer (Sr). Although this model is extensively used its construct validity has been criticized. Between these critics are the fact that only the Sr controls the drug seeking responses because this stimulus overshadows the S, in addition to the fact that little is known about the neural systems that are involved in cue-induced relapse. Therefore, this work had as main purpose to evaluate operant process in the alcohol cue-induced relapse and evaluate the role of stress neural systems in this relapse. In adition, this work had also the purpose to improve the animal model procedure. The experiments presented in Chapter 1 had the purpose to increase the control exercised by S over relapse and to evaluate associative learned in this model procedure. Two experiments were conducted to achieve this goal. In the first one two groups of rats were trained in the cue-induced relapse model but one group was trained under the fixed ratio 1 (FR1) and the other under the variable ratio 5 schedule (VR5). In the second experiment, rats were trained in the cue-induced procedure, but the stimuli S and Sr were presented separately during the training phase. The results showed that separate training was effective in increase the S control over relapse and that changing the schedule of reinforcement was not effective in increase this control. Also, results showed that summation occurred when the stimuli are trained separately and tested as a compound. The experiments presented in Chapter 2 had the purpose to evaluate if neural axis related to organic stress responses are involved in cue-induced alcohol relapse. Also, it was investigated if the HPA is involved in relapse. Marchigian Sardinian Preferring (msP) rats and Wistars rats were trained in the cue-induced model and during the test phase Antalarmin, Metyrapone and corticosterone (CORT) were injected i.p. in the animals. The results showed that Antalarmin (dose 20 mg/kg) blocked relapse produced by environmental cues in both rats strains, Metyrapone (doses 50 mg/kg and 100 mg/kg) blocked relapse in msP rats and only dose 100 mg/kg blocked relapse in Wistar rats and CORT had no effect on relapse in both strains. These results showed that the procedure used in the cue-induced model can be improved mainly in regard to the control from S over relapse. The results also showed that stress responses influence relapse in this model
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Desenvolvimento de um modelo animal para osteoporose induzido por ooforectomia em rato fêmea nude (Rowett) / Development of an animal model for osteoporosis induced by oophorectomy in nude female rat (Rowett)

Azzi, Camila Musumecci Guimarães 11 August 2017 (has links)
A osteoporose é um distúrbio esquelético caracterizado pela diminuição da força óssea, resultando em um risco aumentado de fratura. A perda óssea ocorre tanto em mulheres como em homens devido ao processo de envelhecimento natural [Drake et al.,2015]. De acordo com o diagnóstico e classificação da Organização Mundial da Saúde (OMS), a osteoporose é definida pela densidade mineral óssea (DMO) na coluna lombar ou quadril inferior a -2,5 do desvio padrão abaixo da média da DMO para uma população de jovens adultos [Cosman et al., 2014]. Tem uma alta prevalência sendo mais freqüente do que a soma de casos de infarto do miocárdio, câncer de mama e acidente vascular cerebral. Essa doença deve ser considerada como um problema de saúde pública, pois afeta o indivíduo em sua função social, física e de trabalho e, portanto, causa impacto socioeconômico [Haddad et al.,2015]. Neste trabalho, desenvolvemos um novo modelo de osteoporose em ratos nude por ooforectomia visando o uso de células humanas para a Medicina Traslacional. Para tanto, foram estabelecidos dois passos e a osteoporose foi analisada por densitometria óssea aos 0, 21, 45 e 60 dias após a cirurgia e por análises histológicas de ossos femorais, i) padronização do modelo animal de osteoporose por ooforectomia, utilizando ratos Sprague-Dawley fêmeas de 12 semanas; ii) na segunda fase do projeto, a osteoporose foi induzida em ratos imunodeficientes nude Rowett fêmeas (NTacFCfiq: NIJ-Whn) de 12 semanas e os mesmos ensaios foram conduzidos para detectar a osteoporose. O soro foi coletado para a medida de estrogênio. As análises da DMO e histológicas mostraram modificação do contéudo mineral e ósseos e da estrutura óssea, respectivamente, aos 60 dias após a cirurgia em ambas as linhagens de ratos fêmeas. Com este trabalho, pretendemos contribuir para a compreensão da biologia da osteoporose utilizando um novo modelo animal, o que pode levar ao desenvolvimento de novos protocolos clínicos e terapêuticos no futuro. / Osteoporosis is a skeletal disorder characterized by decreased bone strength resulting in an increased risk of fracture. Bone loss occurs in both women and men due to the natural aging process [Drake et al.,2015]. According to the World Health Organization (WHO) diagnosis and classification, osteoporosis is defined by the bone mineral density (BMD) in the hip or lumbar spine being less than or equal to -2.5 of the standard deviation below the BMD average for a population of young adults [Cosman et al.,2014]. It has a high prevalence being more frequent than the sum of cases of myocardial infarction, breast cancer and stroke. This disease should be considered as a public health problem, since it affects the individual in his social, physical and work function and, therefore, causes socioeconomic impact [Haddad et al.,2015]. In this work, we developed a new rat model of osteoporosis by oophorectomy aiming the use of human cells for Traslational Medicine. To this end, two steps were established, i) standardization of the animal model of osteoporosis by oophorectomy, using female Sprague-Dawley rats at 12 weeks. The osteoporosis was analyzed by bone densitometry at 0, 21, 45 and 60 days after surgery and by histological analyzes of femoral bones. The serum was collected for measurement of estrogen markers; ii) at second stage of the project, osteoporosis was induced in immunodeficient female nude Rowett (NTacFCfiq: NIJ-Whn) at 12 weeks and the same assays were conducted to detect osteoporosis. Bone mineral density and bone histological analyzes showed changes in the of bone mineral content and bone structure, respectively, at 60 days after surgery in both rat lineages. With this work, we intend to contribute to the understanding of osteoporosis biology using a new animal model, which can lead to the development of new clinical and therapeutic protocols in the future.
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Schizophrenia and Substance Abuse Comorbidity: Nicotine Addiction and the Neonatal Quinpirole Model

Brown, Russell W., Maple, Amanda M., Perna, Marla K., Sheppard, A. Brianna, Cope, Zackary A., Kostrzewa, Richard M 01 September 2012 (has links)
This review focuses on nicotine comorbidity in schizophrenia, and the insight into this problem provided by rodent models of schizophrenia. A particular focus is on age differences in the response to
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Identification of a rational, physiologically based early biomarker and pathogenic pathway For preeclampsia

Santillan, Mark K. 01 May 2016 (has links)
Preeclampsia is a hypertensive disorder of pregnancy that is diagnosed after the 20th week of gestation. It is defined by the American College of Obstetrics and Gynecology as de novo hypertension of at least 140/90 in a pregnant woman. Proteinuria with the hypertension is sufficient but not required for the diagnosis, especially if a woman displays severe symptoms such as headache, blurry vision, right upper quadrant pain, and low platelet count. Despite significant research, preeclampsia continues to kill 76,000 mothers and 500,000 babies per year worldwide. It causes short and long term consequences such as future metabolic and cardiovascular events for the mother and the child born during a pregnancy affected by preeclampsia. A delay in diagnosis and delayed access to appropriate care is a core cause of the preeclampsia related morbidity and severe mortality worldwide. Despite being in the medical literature since the time of the ancient Greeks, there is currently no significant predictive, preventative, therapeutic, and curative agent for preeclampsia except for an often preterm delivery of the fetus. The complex pathogenesis of preeclampsia has challenged the ability to effectively predict preeclampsia to decrease the delay in this diagnosis. Consequently, an early intervention or triage to higher level obstetric care is hindered. The lack of an early biomarker for preeclampsia also represents a major barrier to treat preeclampsia before major clinical symptoms emerge and the cycle of future cardiovascular risk for mom and baby begins. Novel, very early pregnancy predictive tests for preeclampsia may provide significant clinical utility. Furthermore, a biomarker that is linked with an early pathogenic mechanism in the first trimester development of preeclampsia would reveal a new avenue of early, first trimester intervention to treat and prevent this devastating disease. This work details the search for such a biomarker linked to an early initiator of the molecular pathogenesis of preeclampsia. These microRNA data highlight very important dysregulated mechanisms including immunologic, cell growth, and angiogenic mechanisms. T cells and the role of indoleamine 2,3 dioxygenase (IDO) is important in the early, maternal immune tolerance to the placenta and pregnancy. As poor placentation is a core cause of preeclampsia, a decreased immune tolerance to it is hypothesized to lead to preeclampsia. Furthermore, low IDO activity has been observed in the placentas of preeclamptic pregnancies which may make it a viable biomarker. These IDO-knock out mouse data, demonstrate that chronic IDO deficiency is sufficient to cause some of the core phenotypes of preeclampsia including renal dysfunction, vascular endothelial dysfunction, fetal growth restriction, and a slight increase in systolic blood pressure. This model does not completely phenocopy human preeclampsia. An investigation of early markers that are linked to vascular, immune, and renal abnormalities highlights the vasopressin pathway as a potential biomarker and early initiator of the pathogenesis of preeclampsia. These data demonstrate that copeptin, as a stable marker of vasopressin secretion, is robustly predictive of the development of late pregnancy human preeclampsia, as early as the 6th week of gestation. Furthermore, a mouse model with chronic infusion of vasopressin throughout mouse gestation phenocopies all the essential aspects of human preeclampsia: pregnancy specific hypertension, proteinuria, pathognomonic glomerular endotheliosis, fetal growth restriction, and increased fetal death. Further research must be done to elucidate the immunologic, vascular, and fetal programming phenotypes of this model. This work posits the possibility that the vasopressin pathway may provide new predictive, preventative, therapeutic, and potentially curative modalities for preeclampsia.

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