INTRODUÇÃO: O tratamento cirúrgico das estenoses uretrais com enxertos limita-se ao emprego de materiais orgânicos, mais freqüentemente autoenxertos. O sucesso no uso de biomateriais sintéticos em diferentes áreas da medicina motivou a pesquisa desses materiais na reconstrução uretral. A informação de que o uso de prótese mamária de silicone recoberta com espuma de poliuretano revelou menor retração cicatricial que as próteses convencionais e o fato desses polímeros já serem empregados como elastômero na confecção de cateteres urinários, levou à escolha deste material para estudo. MÉTODOS: Foi realizada a ressecção de segmento dorsal da uretra anterior de 20 coelhos machos NZW. O defeito uretral foi tratado com o implante no leito uretral dorsal de uma placa não tubularizada de silicone, revestida externamente com espuma de poliuretano (Si-Pu). Como controle foi confeccionado o grupo Sham (GS) com 12 animais. Este grupo foi submetido à uretrotomia dorsal longitudinal e uretrorrafia, sem qualquer tipo de implante. As análises foram feitas com 2, 4, 8 e 24 semanas após a cirurgia. Analisaram-se alterações da circunferência da uretra e complicações cirúrgicas. Fez-se estudo histológico com coloração de Tricrômico de Mason, Hematoxilina-eosina e Picrosírirus red. Foram avaliadas: intensidade e características da resposta inflamatória, espessura da parede da uretra (edema) e concentração do colágeno na submucosa da uretra. Foi realizada análise microbiológica e pesquisa de incrustação do implante por termogravimetria. Os achados foram comparados com os dados de três coelhos que não sofreram qualquer intervenção. RESULTADOS: Não foram encontradas fístulas, estenoses, obstrução, calcificação, retração cicatricial ou deiscências. Ocorreu expulsão do implante em 1/5 dos animais após 4 semanas, em 2/5 com 8 semanas e em 3/5 com 24 semanas. Não houve redução da circunferência da uretra na comparação entre os grupos Experimental (GE) e GS, exceto para o intervalo de 8 semanas. Ocorreu infecção do sítio cirúrgico em 11 de 12 animais do GS e em 13 de 20 animais do GE. As bactéria mais comumente encontradas foram Staphylococcus DNAse negativa (9/32) e Escherichia coli (5/32). A presença de infecção por Enterobacter cloacae foi acompanhada de menor ganho de peso pelos animais (P=0,02), fato não observado na infecção com outras bactérias. A circunferência uretral foi maior (P=0,006) na vigência de infecção por Staphylococcus do que nas amostras estéreis. A histologia do GE mostrou processo inflamatório severo e substituição das fibras musculares da lâmina própria por colágeno com regressão do edema e das células inflamatórias, tardiamente. No GS ocorreu deposição tardia de colágeno e inflamação leve, porém constante. Houve re-epitelização da uretra nos dois grupos. A concentração de colágeno na área manipulada foi maior apenas na comparação entre os GE e GS com 24 semanas (P<0,001). O edema da parede uretral foi maior no GE que no GS nos intervalos de 2 semanas e de 4 semanas com P<0,001, e após 8 semanas com P<0,05. Após 24 semanas não se verificou diferença entre as espessuras da submucosa. Na análise descritiva da termogravimetria observou-se incrustação de material orgânico no implante, que não se mostrou significante estatisticamente na análise quantitativa de perda de massa. A incrustação de material inorgânico ao implante foi desprezível. CONCLUSÕES: O uso do Si-Pu leva à formação de cápsula colágena que permite a re-epitelização da uretra sem ocasionar retração local, funcionando como um biomolde, porém a expulsão do implante limita seu uso / BACKGROUND: Actually, the treatment of urethral stenosis employs biological grafts, usually autologous grafts. The success with synthetic biomaterials in others medical specialtys motivated the search of these materials in urethral reconstruction. The knowledge about the silicone mamarian prosthesis covered with polyurethane foam reduces capsular contracture in breast implants and because these polymers are already used in the urinary tract like catheters make the choice for these materials. METHODS: The resection of dorsal segment of anterior urethra of 20 male rabbits NZW was carried through. The urethral defect was treated with the on lay dorsal graft in urethra, compound a silicone not tabularized, coated with polyurethane foam in one face (Si-Pu). The control group (sham) was confectioned with 12 animals was submitted to longitudinal dorsal uretrotomy and suture, without any type of implantation (SG). The analyses intervals were 2, 4, 8 and 24 weeks after surgery. The circumference of urethra and surgical complications had been analyzed. Material for histological evaluation was stained with Massons thrichrome, hematoxylin and eosin and Picrosirius red. Intensity and characteristics of the inflammatory response, thickness of the urethra (oedema) and concentration of the collagen in the submucosa had been evaluated. Still, was performed microbiological analysis and research of implants incrustation with thermogravimetry. The findings had been compared with the data of three rabbits that had not suffered any intervention. RESULTS: The morfological analysis not founded fistula, obstruction, stenosis, cicatricial retraction, calcification and dehiscence. The graft was extruded after 4 weeks in 1/5 of the animals, in 2/5 after 8 weeks and after 24 weeks, 3/5 of the animals had failure of union with the surrounding tissue. Except for the interval of 8 weeks, It did not have urethral circumference reduction in the comparison between groups, Experimental (EG) and SG. Infection of the surgical place occurred in 11 of 12 animals of the GS and in 13 of 20 animals of EG. Staphylococcus DNAse-negative and Escherichia coli were the most frequent bacterium founded, and occurred in 9/32 and 5/32, respectively. The infection with Enterobacter cloacae was associated to lesser weight gain for the animals (P=0,02), fact not observed in infection with other bacteria. The Staphylococcus infection was associated to larger urethral circumference (P=0,006), when compared to sterile samples. The EG histological analysis showed early severe inflammatory process and substitution of smooth muscle fibers for collagen and regression of edema and inflammatory cells decrease laterly. Occurred delayed deposition of collagen and slight inflammation in the SG, however this process was constant. Was observed urothelial reepithelialization in both groups. The collagen concentration in urethral wall at surgical site was larger in EG with 24 weeks when compared to SG at same time (P< 0.001). There was significantly less urethral wall oedema in SG at 2 weeks, at 4 weeks (P< 0.001) and after 8 weeks (P< 0,05) than EG at the same time. After 24 weeks no difference was verified in submucosa thickness between the groups. The descriptive thermogravimetric analysis showed graft incrustation with organic material, however without statistic significance in quantitative analysis of mass loss. The inorganic graft incrustation was negligible. CONCLUSIONS: The use of Si-Pu implants in urethra originated a fibrous collagen capsule that allows reepitelialization without local contracture, like a biological skeleton. Nevertheless, grafts extrusion limits their clinical employment

O tratamento das lesões ósseas cavitárias com autoenxerto ainda é considerado o padrão-ouro. Seu uso, entretanto, é limitado, devido principalmente à baixa disponibilidade e à morbidade do sítio doador. Os enxertos ósseos sintéticos são estudados com o objetivo de superar as limitações decorrentes da retirada de autoenxerto ou da disponibilidade de bancos de tecidos. O vidro bioativo é um material sintético osteoindutor, osteocondutor e antibacteriano, à base de sílica e cria um arcabouço para o crescimento ósseo. Objetivo: comparar o vidro bioativo com o autoenxerto, com relação às características histomorfométricas. Métodos: foi realizado um estudo experimental prospectivo caso-controle em animais, para comparar o vidro bioativo com o autoenxerto com relação às características histomorfométricas. Oito coelhos foram submetidos a uma cirurgia em que um defeito cavitário foi criado em ambos os fêmures proximais; de um lado, o defeito ósseo criado foi preenchido com os grânulos de vidro bioativo; do outro, o defeito ósseo foi preenchido com o autoenxerto retirado do lado contralateral. Os lados foram randomizados. Catorze dias após a cirurgia os animais foram sacrificados. Resultados: a análise histológica revelou que a neoformação óssea entre os dois grupos foi equivalente, e que a contagem de osteoblastos foi superior nos fêmures tratados com vidro bioativo. A contagem de osteócitos, por outro lado, foi menor. A semelhança na intensidade de neoformação óssea coincide com o encontrado na literatura. As diferenças de contagem celular são concordantes com o mecanismo de ação do vidro bioativo: aumento do turnover ósseo, estímulo dos osteoblastos e retardo na sua diferenciação para osteócitos. Conclusão: o vidro bioativo promove neoformação óssea semelhante ao autoenxerto neste modelo animal de defeito ósseo cavitário. Nível de evidência III, estudo caso-controle / Autograft is still considered the gold standard in the treatment of cavitary bone lesions. The low availability and donor site morbidity, however, limits its use. Synthetic bone grafts have been studied in order to overcome the limitations of autograft or allograft. Bioactive glass is an osteoinductive, osteoconductive and antibacterial silica-based synthetic material. It promotes the creation of a scaffold for bone growth. Objectives: to compare bioactive glass and autograft regarding their histomorphometric characteristics. Methods: the author conducted a prospective case-control experimental study on animals, to compare the histomorphometric characteristics of bioactive glass versus autograft. Eight rabbits underwent surgery in which a cavitary defect was created in both proximal femurs. On one side, the bone defect was filled with bioactive glass granules and on the other, the defect was filled with autograft grafted from the contralateral side. The sides were randomized. Fourteen days after surgery, the animals were euthanized. Results: histologic analysis revealed that bone neoformation was equivalent among the two groups and the osteoblasts cell-count was higher in the femurs treated with bioactive glass. The osteocytes cell-count, however, was lower. The similarity in bone formation between both groups was also found in the literature. The differences in cell-count of osteocytes and osteoblasts are in accordance with the mechanism of action of the bioactive glass: increase in bone turnover, stimulation of osteoblasts and inhibition of their differentiation into osteocytes. Conclusion: bioactive glass is similar to autograft regarding bone neoformation, in this animal model of cavitary bone defects. Level of evidence III, case-control study

O objetivo deste trabalho foi avaliar a neoformacão óssea induzida por um xenoenxerto bovino composto comparativamente ao ósseo autógeno, em cirurgias de levantamento de seio maxilar em coelhos. Nesse estudo utilizouse o seio maxilar de 18 coelhos machos, sendo que no seio maxilar esquerdo foi colocado 200mg de osso autógeno córtico-medular triturado e no seio maxilar direito, o biomaterial, de origem bovina, composto por matriz orgânica cortical e inorgânica medular, \'pool\' de BMPs e colágeno (Gen- Tech®). Realizou-se análise tomográfica por tomógrafo computadorizado (TC) para avaliar a densidade óptica comparativamente entre os grupos e períodos experimentais, a histológica descritiva para verificar a resposta tecidual frente aos materiais implantados e a histomorfométrica para obter os dados de densidade de volume de tecido ósseo neoformado, tecido conjuntivo e/ou granulação, material residual e tecido mielóide. Os resultados obtidos pela TC demonstraram densidade óptica cerca de 2 vezes maior no grupo teste. Na análise histológica observou-se infiltrado inflamatório apenas no período de 2 semanas do grupo teste e exclusivamente ao redor do componente orgânico do biomaterial. Quanto a neoformação óssea, não houve diferença estatisticamente significativa entre os dois grupos experimentais ou ao longo dos períodos, no entanto a área de tecido mielóide foi cerca de 2 vezes maior no grupo controle. Considerando-se os limites do modelo experimental e da técnica empregada podemos concluir que o biomaterial Gen-Tech® é potencialmente indicado como substituto ósseo em cirurgias de levantamento de seio maxilar, uma vez que promove uma neoformação óssea similar à do osso autógeno. / The purpose of this study was to evaluate new bone formation induced by a bovine xenograft compared to autogenous bone in maxillary sinus augmentation in rabbits. The maxillary sinus of 18 male rabbits were used, whereas the left sinus was filled with 200mg of a mixture of cortical and medullar autogenous bone and the right sinus was filled with a mix of organic and inorganic bovine matrix, plus \'pool\' of BMPs and collagen (Gen-Tech®). Computer tomography (CT) analysis was realized to evaluate and compare the optical density among the groups and experimental periods; descriptive histologic analysis was used to verify the tissue response to the materials implanted. In addition, histomorphometric analysis was realized to evaluate volume density of the newly formed bone, connective tissue and/or granulation tissue, residual material and myeloid tissue. The results obtained in the CT demonstrated an optical density approximately 2 times greater in the test groups. Histological analysis revealed an inflammatory infiltrate at 2 weeks in the test group and exclusively around the organic portion of the material. Regarding new bone formation, no statistical differences were observed among the two experimental groups or throughout the experimental periods. However the area of myeloid tissue was 2 times greater in the control group. Considering the limits of the experimental model and technique used in this study, it is possible to conclude that Gen-Tech® is a biomaterial with potential applications as a bone substitute in maxillary sinus augmentation once it is able to promote the formation of new bone similarly to autogenous bone.

As técnicas de remoção da catarata evoluíram consideravelmente nos últimos anos. No entanto, apesar do aprimoramento de novas técnicas e equipamentos, a inflamação resultante da manipulação e da remoção da lente é ainda uma das principais causas de complicações pós-operatórias. Desta forma novos anti-inflamatórios têm sido testados para o melhor controle da inflamação no sentido de aumentar o sucesso da cirurgia. O objetivo do presente trabalho foi comparar os efeitos anti-inflamatórios do nepafenaco 0,1% e da dexametasona 0,1% no tratamento da inflamação decorrente da facoemulsificação experimental em coelhos. Para tanto 21 coelhos foram submetidos à facoemulsificação do olho direito e distribuídos em três grupos: Grupo ST recebeu colírio de moxifloxacino 0,5% quatro vezes ao dia por 15 dias; Grupo CORT recebeu associação de colírios dexametasona 0,1% e moxifloxacino 0,5% quatro vezes ao dia por 15 dias; Grupo NEPA - recebeu associação de colírios nepafenaco 0,1% e moxifloxacino 0,5% quatro vezes ao dia por 15 dias. Os animais foram submetidos à avaliação clínica, mensuração de pressão intra-ocular, mensuração da espessura corneal e coleta de humor aquoso imediatamente antes do procedimento cirúrgico, 1, 2, 3, 7 e 15 dias após a cirurgia. As amostras foram armazenadas a -80°C para mensuração dos níveis de prostaglandina, proteína e ácido ascórbico. Com relação aos parâmetros clínicos, observou-se diferença para secreção ocular no momento T2 onde o grupo NEPA apresentou menor escore. O mesmo foi observado nos momentos T2 e T7 para hiperemia conjuntival, nos momentos T2 e T3 para opacidade corneal e no momento T3 para fibrina em câmara anterior. A paquimetria corneal não mostrou diferença significante entre os grupos, com exceção do momento T15 quando os grupos NEPA e CORT mostraram paquimetria inferior ao grupo ST. Os níveis de prostaglandina mostraram-se inferiores no grupo NEPA nos momentos T1 e T2 ainda que nos demais momento exista maior agrupamento de animais nos intervalos de menor concentração de PGE. Não se observou diferença entre os valores da pressão intra-ocular entre os grupos com exceção do momento T1 em que houve um pico de PIO no grupo CORT (35,7 ± 10,73 mmHg). Em relação à contagem de células não se observou diferença entre os grupos com exceção do momento T3 que mostrou menor número de células no grupo CORT. Os níveis de ácido ascórbico foram superiores no grupo NEPA em todos os momentos, porém apenas em T7 e T15 com diferença estatisticamente significante em relação ao CORT. O grupo CORT mostrou a concentração de proteína nos dois primeiros dias (T1 e T2) e a partir do momento T3 o grupo NEPA passou a apresentar concentrações de proteína discretamente menores. O grupo ST mostrou concentrações superiores em todos os momentos. O tempo de Ultra-som utilizado nos três grupos não diferiu estatisticamente. Desta forma podemos dizer que o nepafenaco foi eficiente na inibição da inflamação, redução da PCC e controle da PIO, sendo superior à dexametasona na inibição da formação de prostaglandina no HA e no restabelecimento dos níveis de ácido ascórbico na câmara anterior. / The techniques of cataract removal have developed considerably in the last years. Despite of the improvement of new techniques and equipments, inflammation resultant from manipulation and lens extraction remain one of the main causes of post-operative complications. New anti-inflammatory drugs have been tested to better control inflammation and therefore increase success of the surgery. The purpose of the study was to compare the anti-inflammatory effects of nepafenac 0,1% and dexametasone 0,1% eye drops after experimental phacoemulsification in rabbits. Twenty one animals were submitted to phacoemulsification of the right eye and divide into three groups: Group ST - moxifloxacin 0,5% eye drops 4 times a day; Group CORT - dexametasone 0,1 % and moxifloxacin 0,5% eye drops 4 times a day; Group NEPA - nepafenac 0,1% and moxifloxacin 0,5% eye drops 4 times a day. Animals underwent clinical evaluation and values of intra-ocular pressure and central corneal pachimetry were assessed and a sample of aqueous humor was taken immediately before the surgical procedure and at days 1, 2, 3, 7 and 15 after surgery. The aqueous humor samples were storage at - 80°C and the levels of prostaglandins, protein and ascorbic acid were measured. No difference in blepharospasm was noted between groups. Group NEPA showed lower scores of ocular discharge only at day 2. The same was noted at days 2 and 7 for conjunctival hyperemia, at days 2 and 3 for corneal opacity and at day 3 for fibrin inside the anterior chamber. Corneal pachimetry showed no difference between groups except at day 15 when groups CORT e NEPA showed lower corneal pachimetry when compared to control group. Regarding the prostaglandin, NEPA group showed the lowest levels; however statistical difference was only observed at days 1 and 2. Values of intra-ocular pressure showed no statistical difference except at day 1 when a peak was noted in CORT group (35,7 ± 10,73 mmHg). No difference between groups was noted in inflammatory cell counting but in day 3 CORT group showed less cells. The ascorbic acid levels of the NEPA group were higher in all days but statistical difference was only observed at days 7 and 15. Group CORT showed lower concentration of protein at days 1 and 2 and from days 3 to 15 NEPA showed slightly lower concentration. Group ST showed highest concentrations at all moments. Mean values of ultra-sound time were not statistically different between NEPA, CORT and ST groups. Nepafenac showed to be efficient in reducing CCP, controlling IOP and inflammatory clinical signs when compared to dexamethasone and was more efficient than dexamethasone 0,1% in the recovering of the of the humor ascorbic acid levels and inhibiting PGE2 production in aqueous humor.

Made available in DSpace on 2014-06-11T19:22:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-05Bitstream added on 2014-06-13T20:28:20Z : No. of bitstreams: 1 novellifilho_jlvb_me_botfm.pdf: 1212917 bytes, checksum: 117622a272f4c3d2881aed9520f95df9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A lesão do tendão do calcâneo é comum em humanos. Entretanto, existem muitas opiniões sobre o melhor tratamento para esta lesão quando diagnosticada tardiamente, e apesar do grande número de estudos, o melhor procedimento cirúrgico para o reparo ainda não foi identificado. No presente trabalho um modelo experimental foi desenvolvido em coelhos, para o reparo do tendão do calcâneo, com retalho único da fáscia miotendinosa do M. gastrocnêmio. Foram utilizados vinte e quatro coelhos machos adultos, de peso médio 3382g, divididos em três grupos de oito animais, submetidos à reconstrução cirúrgica do tendão do calcâneo, realizada no membro caudal direito, com o grupo controle no membro caudal esquerdo, não operado. O estudo foi realizado com três tempos de evolução pós-operatória: grupo (T0) amostras coletadas logo após a cirurgia; grupo (T1) amostras coletadas quatro semanas após a cirurgia; grupo (T2) amostras coletadas dezoito semanas após a cirurgia. Os animais apresentaram elevação significativa do peso corporal após 18 semanas da cirurgia. Houve redução na carga máxima, tensão, módulo de elasticidade, energia/área e energia na carga máxima imediatamente após a cirurgia. Após 4 semanas, a carga máxima, tensão, módulo de elasticidade, energia/área e energia na carga máxima mostraramse reduzidas em comparação ao controle. Após dezoito semanas os parâmetros mecânicos deformação, tensão, energia na carga máxima e energia/área foram restabelecidos. Concluiu-se no presente estudo, que a reconstrução do tendão do calcâneo com retalho único da fascia miotendinosa do M. gastrocnêmio, não se igualou ao controle em todos os parâmetros mecânicos após dezoito semanas, e que o modelo experimental foi adequado para a reprodução desta técnica cirúrgica em coelhos. / Calcaneus tendon injuries are commom in humans. However, there are many opinions about the best treatment for this lesion when too late diagnosed, and despite the large amount of studies, the best surgical procedure for repair wasn´t identified yet. In this study a experimental model in rabbits was developed for calcaneus tendon repair, with one single morsel from M. Gastrocnemius fascia. Twenty four male adult rabbits were employed, with medium weight 3382g, divided in three groups with eight animals each, submited to surgical procedure for repair of calcaneus tendon, accomplished on the rigth hind limb, with the control group on the left hind limb, not operated. The study was developed with 3 post-operation evolution times: group (T0) samples colected just after surgery; group (T1) samples colected four weeks after surgery; group (T2) samples colected eighteen weeks after surgery. The animals have had rising on weight bearing after eighteen weeks of surgery. There was reduction on maximum load, stress, elasticity modulus, energy/area and energy on maximum load just after surgery. After 4 weeks, the maximum load, stress, elasticity module, energy/area and energy on maximum load showed reduction in comparison with control. After eighteen weeks of surgery, the mechanical parameters deformation, tension, energy on maximum load and energy/area were restabilished. We concluded in this study, that the repair of the calcaneus tendon with one single morsel from M. gastrocnemius fascia, did not equalize with control group in all mechanical parameters after eighten weeks, and the experimental model, was suitable for the reproduction of this technic in rabbits.

Thesis (M. Sc. (Agriculture)) -- University of Limpopo, 2004 / National Research Foundation (NRF)

The secretion of the acqueous component of tears is dependent on the uneven distribution and nature of ion channels across lacrimal gland acinar cell membranes. Models to describe such secretion in lacrimal glands are based primarily on one species, the rat and have been developed in conjunction with observations of channel function and secretion from salivary and pancreatic exocrine glands, which are structurally similar to lacrimal glands. The applicability of these models to all species is unknown and furthermore none takes into account volume regulation mechanisms in these acinar cells. Therefore, the aim of this thesis was to broaden the basis for such models by identifying the major membrane ionic channels, characterising their mode of activation and determining their possible physiological roles in rabbit superior lacrimal gland acinar cells. Initially, a culture system for maintaining acinar cells for short and long terms was developed. This allowed for electrophysiological techniques to be employed to study the role of ionic channel activity in the secretion of the aqueous component of tears and cell volume regulation. This study demonstrates a number of unique findings and indicates that the models currently used to describe lacrimal gland secretion are not applicable to all species and need modifications which take into account cell volume regulation / Doctor of Philosophy (PhD)

There is a need to develop a range different VLP for use as nanoscale templates and vaccines. The aim of this research was to develop RHDV VLP as a versatile vaccine delivery system easily modified for use against a wide range of different diseases. Production of Rabbit haemorrhagic disease virus (RHDV) capsid protein in a baculovirus system led to the self-assembly of Virus-like Particles (VLP) that could be purified to greater than 99% purity using simple methods. The capsid gene, vp60, can be manipulated genetically to incorporate immunogenic peptide sequences or a functional DNA-binding site. Fusion of these small epitopes to VP60 was well tolerated, forming VLP and greatly enhanced the presentation of peptide to, and activation of CD4+ T helper cell hybridoma. To avoid constraints imposed on chimeric VLP and dramatically increase the versatility of RHDV VLP, rapid conjugation of antigen was carried out, employing the hetero-bifunctional chemical linker, sulpho-SMCC. Incorporation of sulfhydral groups by design or treatment with SATA allowed for great versatility, in turn enabling many diverse peptides and proteins to be conjugated to VLP. RHDV VLP and consequently the conjugated GFP antigen were efficiently taken up by DC with more than 85% of DC positive for GFP by flow cytometry. This was also visualised by confocal microscopy and electron microscopy of both gold- labelled VLP and conjugated antigen. RHDV VLP conjugate was shown to induce the significant up regulation of the activation markers CD40, CD80, CD86 and MHC class II on the surface of dendritic cells (DC). As well, DC pulsed with RHDV VLP/OVA effectively presented OVA to both CD4+ and CD8+ T cells transgenic for respective peptide-specific T cell receptors, eliciting a greater proliferative response in both T cell subsets than antigen delivered alone. The surface accessibility of peptides on VLP was demonstrated, while administration of VLP/Ovalbumin (OVA) conjugate in mice was shown to evoke very high titre antibody responses specific for conjugated antigen. VLP/OVA conjugates were also shown to induce IFN-γ production and OVA-specific cytotoxic killing in vivo, of up to 80% of fluorescently labelled, adoptively transferred target cells. No distinguishable cytotoxicity was detected in unimmunised control mice. This assay was also used to demonstrate the necessity for antigen to be conjugated to VLP, as antigen mixed with VLP induced only sub-optimal killing. To investigate the anti-tumour effects, mice vaccinated with VLP conjugated to OVA protein, CD4+ or CD8+ T cell OVA epitopes were inoculated with B16- OVA tumour cells and monitored for tumour growth. Untreated control mice had to be sacrificed by day 19, while mice immunised with either VLP/OVA or VLP conjugated with both CD4+ and CD8+ OVA epitopes, showed a significant delay in tumour growth (P = 0.0002), with one mouse remaining free of palpable tumour until day 92. These results show that RHDV VLP can be easily produced and purified and demonstrate the versatility of this RHDV capsid. Rapid conjugation techniques allowed the modification of VLP with both peptide and protein rendered these antigens highly immunogenic, stimulating both humoral and cell-mediated immunity targeted against conjugated antigens of choice. The versatility and immune stimulating properties of RHDV VLP provides a molecular tool with almost limitless applications within the fields of nanotechnology and immunology.

Previous research attests to the relationship between social support and positive health outcomes while linking social isolation or aggression/hostility with negative health outcomes. Several studies examining atherosclerosis with either genetic or behavioral origins, have reported decreased disease severity in socially supportive environments. In order to identify and understand the mechanism responsible for decreased disease, the current study examined physiological differences in New Zealand White rabbits within unstable, stable, and isolated social environments and observed whether functional hormonal changes were apparent over time and as a response to behavior characteristic of these environments. Results indicated that animals within the unstable condition displayed increased agonistic behavior, increased cortisol and epinephrine, decreased body weight, epididymal fat, and retroperitoneal fat, as well as larger spleens. Cortisol values positively correlated with measures of agonistic behavior for all animals, while the reverse relationship was found for affiliative behavior. The novel finding of an increase in oxytocin in animals in the unstable condition within the first ten minutes of pairing that was noticeably distinct from the other two groups suggests that plasma oxytocin levels are related to acute stress. Limitations and interpretations of these findings are discussed. Future work is still needed to help further explain the physiological response to social stress and affiliation and to elucidate the mechanism by which a supportive social environment appears to protect against progression and severity of heart disease.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 77-93).