Calcification is linked to a high prevalence of cardiovascular events and mortality due to arterial stiffness. Stiffening of the arteries in the case of medial calcification is due to hydroxyapatite mineral deposited in the artery thus leading to the loss of elastin. A possibility of removing this rogue mineral along the vessel walls could be the use of osteoclasts. Osteoclasts, a type of osteocyte, have the unique ability to absorb bone in the bone turnover process. It is proposed that in the future, osteoclasts be delivered to the site of mineralization through oxidized alginate-fibrin microbeads. Alginate hydrogels have proven great in drug delivery and could be a revolutionary cell delivery device to provide care for multitudes of people suffering from adjacent cardiovascular health problems such as arterial stiffness.

The hippocampus is a brain region that can undergo tremendous plasticity in adulthood. The hippocampus is related to the formation of spatial memories in birds and mammals. In birds, plasticity in the hippocampus occurs when formation of such memories is directly relevant to survival or reproduction, such as for breeding or food caching. In reptiles, the homologues to the hippocampus are the dorsal and medial cortices (DC and MC). In several lizard, snake and turtle species, these structures have been related to spatial memory. Experimental investigations indicate that differences in DC volume are related to space use associated with differing foraging ecologies. Differences in MC volume have been associated with territory size-based mate acquisition strategies. Furthermore, territory size has previously been correlated with plasma testosterone (T) levels. Therefore, I hypothesized that neuroplasticity within the MC/DC is controlled by demands on spatial navigation and seasonal differences and that these changes may involve the action of T. During two experimental trials, male Western Fence Lizards (Sceloporus occidentalis) were placed into either large or small semi-natural enclosures and allowed to interact with a female and intruder males over the span of seven weeks. One trial was performed during the spring breeding season and the other during the summer non breeding season, to examine seasonal differences in plasticity. Blood samples were collected at initial time of capture and before sacrifice to measure plasma T. Immunostaining for doublecortin was used to determine the density of immature neurons in each region, and cresyl violet staining allowed for volume measurements of specific regions. MC cell layer neurogenesis was higher in lizards placed in large enclosures than those in small enclosures and higher in the summer than in the spring. DC volume was smaller in lizards held in large enclosures than those in small enclosures. The decreased DC volume seen lizards held in large enclosures may indicate a cost to the increased neurogenesis in the MC of lizards in the same enclosures. These results indicate a possible trade-off between DC volume and MC neurogenesis that allows for switching between the ability to solve novel spatial tasks using the DC while storing a cognitive map in the MC. During the spring, T had no relationship with MC volume, while during the summer this was negative, so effects of T on the MC may be seasonal.

No description available.

No description available.

Temporal context memory is memory for the timing of events. People can make temporal judgments based on strategies such as assessing the relative familiarity of events or inferring temporal order from the semantic associations among events. The purpose of present study is to investigate the brain regions that support temporal context retrieval in the absence of such non-temporal strategies (i.e. pure temporal context memory). We used three word familiar phrases (triplets) as stimuli. In study phase, three words were presented quickly one after another in either familiar or scrambled order. Participants were instructed to read aloud each word and try to remember the order of the words. Then they were tested on their memory for the order of the words in each triplet. We propose that memory for the scrambled triplets reflects primarily temporal retrieval for two reasons. First, participants were prevented from using semantic strategies during encoding. Second, the relative familiarity of the words in each triplet was similar and not diagnostic of the order of the words during encoding. Neuroimaging results indicate that temporal context retrieval, memory for the order of words in scrambled triplets, was associated with the hippocampus, parahippocampal cortex, ventromedial prefrontal cortex, retrosplenial cortex, and posterior cingulate, which are consistent with the retrieval of non-temporal context in episodic memory. The results also suggest that temporal context retrieval could rely on familiarity, which was demonstrated by the higher accuracy and greater activation of PRc in familiar phrases and scrambled triplets presented in studied order in the test phase. / Master of Science

Medial Oxford unicompartmental knee replacement (UKR) is an established and successful treatment for patients with antero-medial knee osteoarthritis. However, following the operation some patients have pain which compromises their functional outcome. The aims of this thesis were to determine the incidence of pain, to identify the patient, disease and surgical risk factors associated with this pain and to try and understand why it occurs. The clinical studies were performed using patients operated on by experienced surgeons. The incidence of post-operative severe pain was 3% at six weeks and 2% at one year and the incidence remained unchanged at subsequent follow ups. The overall incidence of pain has reduced over the years. In patients who had UKR between 1998 and 2001, the incidence of severe pain was 5%; this reduced to 2.3% for the period between 2008 and 2011. As the indications have not changed, the improvement is probably due to modifications in the surgical technique and due to improvements in instrumentation. Patients with severe pain at the final follow up had a worse neuropathic pain score, and the patients with possible pre-operative neuropathic pain achieved significantly worse outcome. To explore the effect of disease severity on outcome, matched cohorts of patients with partial thickness cartilage loss (PTCL), bone-on-bone and bone loss were compared. All those with bone-on-bone and bone loss did well, whereas 20% of those with PTCL did not benefit from the surgery; 7% had severe pain and 17% had pain related complications. Although component and leg alignment, and component overhang have a profound effect on the outcome of total knee replacement (TKR), their effect on the outcome of the Oxford UKR are not known. It was found that malalignment in the coronal or sagittal planes of the femoral component within ±10° and of the tibial component within ±5° did not compromise the outcome. Leg alignment was not related to outcome even though 18% were in 5° varus and 8% were in 10° varus. In contrast, tibial component overhang ≥3 mm compromised the outcome and 21% of these patients continue to suffer from pain. The presence of radiolucent lines (RLL) following a joint replacement is usually deemed to be indicative, or predictive, of loosening. 63% of Oxford UKRs were found to have RLL under the tibial component. No correlation was found between RLL and outcome, particularly pain. It has been suggested that post-operative pain, which is commonly antero-medial over the proximal tibia, may be related to bone overload. This was explored using the finite element (FE) analysis. Following implantation of the Oxford UKR, the strains in the antero-medial region doubled. Various implantation, loading and alignment variables were studied and the findings correlated with the clinical studies, suggesting that high strain is an important cause of pain. With time, the bone will remodel, so the strains will decrease but individual differences in the remodeling threshold may explain resolution of symptoms in some, but not in all, patients. In conclusion, this work has shown that following the Oxford UKR, pain is a rare but important complication. The chance of pain can be decreased by operating only on patients with bone-on-bone arthritis and taking care with the surgical technique. Bone overload is likely to be an important cause of pain, and further modification to the implant or technique, such as achieving fixation of the tibial component vertical wall to bone, may further decrease the incidence of pain.

Este trabalho objetivou avaliar através do exame clínico, radiográfico e ultra-sonográfico a articulação fêmuro-tíbio-patelar pós desmotomia patelar medial. Foram utilizados oito equinos, machos e fêmeas, de peso, raça e idade variáveis. Todos animais foram submetidos a desmotomia patelar medial no membro pélvico direito. Os exames clínico e ultra-sonográfico foram realizados no 7º, 14º, 21º, 28º, 43º, 58º, 88º e 118º dia do pós-operatório. Os exames radiográficos e do líquido sinovial foram realizados no 15º, 30º, 60º, 90º e 120º dia do pós-operatório. No pós-operatório foi observado durante exame radiográfico do joelho direito, aumento do ângulo entre a superfície articular proximal da patela e a superfície cranial distal do fêmur, formação óssea na crista tibial, entesofitos na patela, deslocamento da patela e irregularidade óssea na superfície patelar lateral. No exame ultra-sonográfico foi observado aumento da espessura (p<0,05) no segmento proximal e médio do ligamento patelar intermédio do membro pélvico direito, desmite do patelar intermédio, enteseofitos na patela, distensão do recesso articular medial do fêmur, efusão articular e irregularidade da cartilagem do sulco troclear femoral. Conclui-se que a desmotomia patelar medial causa alterações no joelho devido a instbilidade articular e deve ser indicada apenas nos casos que não responderam a outras forma de tratamento. / This study aimed the evaluation of the femurotibiopatellar joint trough clinical, radiographic and ultrasonographic examinations after experimental medial patellar desmotomy. Medial patellar desmotomy was performed on the right hindlimb in eight mixed-breed horses. The clinical and ultrasonographic evaluation was performed on day 7, 14, 21, 28, 43, 58, 88 e 118 after surgery. The radiographic and synovial fluid evaluation was performed on day 15, 30, 60, 90 e 120 after surgery. It was observed during radiographic evaluation of the right stifle, an increase of the angle between the patellar proximal articular surface and the cranial distal femur surface. During ultrasonographic evaluation it was observed thickening (p<0,05) on the proximal and midlle segment of the midlle patellar ligament on the right hindlimb, entesophyte at the patella, femoral medial joint recess distending, joint effusion and cartilage irregularity of the femoral troclear groove. The medial patellar desmotomy causes stifle changes and must be performed only in animals non responsive to other treatment.

Acredita-se que quantidades elevadas de glutamato estejam relacionadas à neurobiologia da depressão e trabalhos recentes indicam que a quantidade de glutamato cortical está aumentada em pacientes depressivos quando comparada a indivíduos sadios. Dentre as estruturas corticais, o córtex pré-frontal medial ventral (CPFMv), dividido em infralímbico (IL) e pré-límbico (PL), tem sido mais frequentemente implicado no desenvolvimento de transtornos mentais, como a depressão. Considerando evidências de que o IL e o PL podem agir de forma diferente quanto ao controle emocional em resposta ao estresse, o presente trabalho visou avaliar a hipótese de participação da neurotransmissão glutamatérgica do CPFMv, IL e PL, no desenvolvimento das respostas comportamentais ao estresse de nado forçado, um modelo preditivo de efeitos antidepressivos. Para tal, investigamos os efeitos induzidos pela administração no IL ou no PL, de LY 235959, um antagonista dos receptores glutamatérgicos do tipo NMDA, em três momentos diferentes, em animais submetidos ao teste do nado forçado. A administração de LY 235959, no IL ou PL, produziu efeitos do tipo antidepressivo, sendo esse efeito sensível ao tempo de administração da droga em relação à exposição ao nado forçado. Sendo assim, foi observado efeito antidepressivo quando o bloqueio glutamatérgico no PL ocorreu imediatamente após o nado ou antes da re-exposição ao estresse; enquanto no IL, o tratamento promoveu efeito antidepressivo apenas quando administrado antes da re-exposição ao nado. Portanto, os resultados sugerem que a neurotransmissão glutamatérgica mediada por receptores NMDA no CPFMv contribui para o desenvolvimento de consequências comportamentais do estresse, de modo que o bloqueio desses receptores facilitaria a adaptação ao estresse e induziria efeitos do tipo-antidepressivo. Os resultados sugerem, ainda, que o PL e o IL participam de maneira semelhante na modulação desses processos. / It is believed that high amounts of glutamate are related to the neurobiology of depression. Recent studies indicate that the amount of cortical glutamate is increased in depressed patients compared to healthy subjects. Among the cortical structures, the ventral medial prefrontal cortex (CPFMv), divided into infralimbic (IL) and prelimbic (PL) has been most often implicated in the development of mental disorders, such as depression. Considering that IL and PL play different roles on the emotional control in response to stress, this study was aimed to evaluate the hypothesis that the activation of glutamate NMDA receptors within the CPFMv, IL and PL, would facilitate the development of forced swimming-induced behavioral responses, an animal model predictive of antidepressants effects. To this end, we investigated the effects induced by the administration in the PL or the IL of LY 235959, an antagonist of NMDA receptors, at three different times, in animals submitted to the forced swimming test. The administration of LY 235959, in the IL or PL, produced antidepressant-like effects, and this effect is sensitive to moment of drug administration in relation to exposure to forced swimming. Thus, the antidepressant-like effect was observed when blocking the NMDA blockade into the PL occurred immediately after swimming or before re-exposure to stress, whereas in the IL, such treatment promoted antidepressant-like effect only when administered before re-exposure to swimming. Therefore, the results suggest that the glutamatergic neurotransmission mediated by NMDA receptors in the CPFMv contributes to the development of behavioral consequences of stress, so that blocking these receptors would facilitate the adaptation to stress and induce antidepressant-like effects. The results also suggest that PL and IL may be similarly involved in modulating these processes.

Representações computacionais de formas podem ser criadas em ferramentas CAD ou geradas a partir de um objeto físico já existente. Esta última abordagem oferece como vantagens rapidez e fidelidade ao objeto original, que são os aspectos fundamentais em muitas aplicações, como Simulações Numéricas de Equações Diferenciais Parciais e Imagens Médicas. A reconstrução (ou geração de malhas superficiais) a partir de pontos amostrados de uma superfície de um objeto é um problema clássico de representação de formas. Nesta dissertação apresentamos um vasto levantamento bibliográfico deste tipo de reconstrução, classificando e descrevendo os principais trabalhos presentes na literatura. A partir do levantamento bibliográfico, selecionamos um conjunto de algoritmos sobre os quais foram realizadas comparações teóricas e empíricas cujos resultados são apresentados. Para finalizar, apresentamos aplicações de nossas implementações em Simulação Numérica de Equações Diferenciais Parciais e processamento de Imagens / Computational representations of shapes can be developed using CAD applications or created from data acquired from a real physical object. This latter is advantageous with respect to time and fidelity to the original object which are essential to several applications, such as Numerical Simulation of Partial Differential Equations and Medical Imaging. A classical shape representation problem is that of reconstruction (or superficial mesh generation) from points sampled over the surface of an object. In this Master\'s thesis we describe a broad survey of these reconstruction methods. We focus in the classification and characterization of the main algorithms proposed in the literature. From this survey, we selected some algorithms and conducted some theoretical and practical comparisons. We conclude this work describing applications of the algorithms implemented in Numerical Simulations of Differential Partial Equations and Image Processing

As características das células musculares e da junção miotendínea do músculo pterigóideo mediai de ratos adultos e com envelhecimento foram estudadas, empregando-se as técnicas de microscopia de luz e eletrônica de varredura e de transmissão. A microscopia de luz mostrou que as fibras musculares inserem-se na superfície óssea mandibular através de tecido colágeno composto por numerosos fibroblastos. Os cortes examinados sob luz polarizada revelaram a presença de fibras colágenas tipo\' e li\' nesta região. Além disso, puderam-se notar os capilares sangüíneos em grande número. Observações ao microscópio eletrônico de varredura ressaltaram as estriações presentes no músculo esquelético. O tecido conjuntivo que constitui o endomísio foi notado quando as amostras foram tratadas com solução de hidróxido de sódio e foi possível observar os diferentes diâmetros apresentados pelas fibras musculares. A microscopia eletrônica de transmissão evidenciou o alinhamento dos sarcômeros e as concentrações de mitocôndrias junto à lâmina basal na terminação da fibra muscular. O estudo da junção miotendínea dos ratos adultos e com envelhecimento identificou as fibras colágenas e os feixes de miofibrilas formando interdigitações que promovem o aumento da superfície de contato nesta região. Os aspectos observados nos músculos de ratos adultos mostraram-se bastante similares aos encontrados nos ratos com envelhecimento. / The mediai pterygoid muscle cells and myotendinous junction characteristics of adult and aging rats were studied, using light microscopy and scanning and transmission electron microscopy techniques. The Iight microscopy showed the muscle fibers inserting in the mandible surface through collagen tissue and numerous fibroblasts. The samples examined in polarized light revealed the presence of type I and 11I collagen fibers in this site. Furthermore, the numerous blood capillaries could be noticed. Observations at the scanning electron microscope evidenced strias present in the skeletal muscle. The connective tissue that constitutes the endomysium could be noticed when the samples were treated with sodium hydroxide solution and it was possible to observe the muscle fibers different diameters. The transmission electron microscopy revealed the sarcomeres alignment and the mitochondria concentration by the basal lamina in the muscle fiber termination. The adult and aging rats myotendinous junction study showed the collagen fibers and the myofibrils bundles developing finger-like processes that increases the contact areas in this site. The aspects seen in adult rats pterygoid muscles were very similar to the ones seen in the aging rats.