A identificação e biópsia do primeiro linfonodo a receber a linfa de uma formação neoplásica, ou seja, do linfonodo sentinela, fornecem informações essenciais para o tratamento e prognóstico de pacientes humanos acometidos por neoplasia. Entretanto, em Medicina Veterinária existem poucos estudos sobre a drenagem linfática dos órgãos e o conceito de linfonodo sentinela ainda não é amplamente aplicado ao tratamento oncológico dos animais. Desta forma, nosso objetivo no presente estudo foi estabelecer um protocolo de aquisição cintilográfica linfática, ou linfocintilográfica, capaz de fornecer informações funcionais e topológicas da drenagem linfática mamária, pois, em cadelas, as glândulas mamárias ainda são uns dos principais órgãos acometidos por neoplasias. Neste estudo, a linfocintilografia foi utilizada para caracterização topológica e funcional in vivo da drenagem linfática de glândulas mamárias sadias de 30 fêmeas da espécie canina (Canis familiares), sem raça definida e peso aproximado de 10 Kg. O radiofármaco [99mTc]-dextran70 foi administrado por via intraparenquimatosa mamária em quatro pontos ao redor da papila (0,1 ml cada), na dose de 18,5 MBq. As imagens foram obtidas em duas seqüências de projeções laterais e ventrais, sendo uma logo após a administração do [99m</SUP Tc]-dextran70 e a outra após uma hora. O radiofármaco administrado nas glândulas mamárias torácicas craniais foi drenado pelos linfocentros torácico ventral e axilar, sendo que em duas destas 5 glândulas (40%) o radiofármaco também foi para o linfocentro cervical superficial. Este resultado foi semelhante para as glândulas torácicas caudais, entretanto, em nenhuma das linfocintilografias destas glândulas o linfocentro cervical superficial foi identificado. A drenagem das glândulas abdominais craniais foi realizada exclusivamente pelo linfocentro axilar. Os linfocentros inguinais superficial e profundo drenaram as glândulas abdominais caudais e inguinais, porém, uma das glândulas abdominais caudais foi drenada também pelo linfocentro cervical superficial e outra pelo linfocentro mediastínico. A técnica linfocintilográfica utilizada possibilitou a identificação de comunicações linfáticas entre os linfonodos axilares próprio e acessório, entre o axilar próprio e o cervical superficial e entre os linfonodos inguinais superficial e profundo. O número de linfocentros e linfonodos, a taxa de drenagem dos linfocentros e seu funcionamento variaram entre as glândulas mamárias e entre os animais. Em conclusão, o protocolo de aquisição linfocintilográfica adotado foi simples, rápido e eficaz para a caracterização da drenagem linfática mamária. As informações topológicas e funcionais obtidas neste estudo poderão ser aplicadas nos procedimentos investigativos como a ultra-sonografia e a biópsia dos linfonodos mamários em pacientes acometidos por neoplasias mamárias, uma vez que os vasos linfáticos representam vias de disseminação para células neoplásicas. / The knowledge of lymphatic drainage has prognostic and surgical value for oncological treatment. Once you know the lymph nodes that drain the organ, you can predict the possible neoplasic cell route and avoid or predict metastasis. The lymphoscintigraphy is not common in Veterinary Nuclear Centers, however this technique has high applicability in oncological studies. During this study, the lymphoscintigraphie was used to characterize topological and functional aspects of lymphatic health mammary drainage in 30 adult mongrel female dogs, 10Kg in weigh. Lymphoscintigraphies were performed immediately after 4 intramammary peripapilare injections (0, 1 ml each) of 18,5 MBq of [99mTc]-dextran70 and one hour later. Animals were imaged by lateral and ventral projections. Cranial thoracic glands were drained by ventral thoracic and axillary lymph centers, but we observed the simultaneous participation of superficial cervical lymph center in 40% of these (2 animals). This result was similar for caudal thoracic mammary glands, but not for cervical lymph center drainage, that was not observed in caudal thoracic glands lymphoscintigraphies. Cranial abdominal glands were drained exclusively by the axillary lymph center. Superficial and deep inguinal lymph centers drained caudal abdominal and inguinal mammary glands, but we observed one superficial cervical lymph center participation in a caudal abdominal mammary gland drainage. Our lymphoscintigraphic technique provided image of lymphatic communication between axillary lymph nodes and between superficial and deep inguinal lymph nodes. The number of lymph centers and lymph nodes, the lymph center drainage rate and functional behavior of each lymph nodes were variable. In conclusion, the lymphoscintigraphic protocol performed was simple, quickly and provided the lymphatic drainage characterization. Technique, topologic and functional information provided by the present study can be applied to understand neoplasic mammary cells dissemination routes, which has prognostic and treatment value for patients. Veterinary centers that have no Nuclear Medicine facilities can use these topologic and functional information of the present study in other diagnostic procedures such as the abdominal ultra-sound and lymph node biopsy of patients with mammary neoplasia.

This thesis focuses on the enhancement of the IEEE 802.15.4 beaconless-enabled MAC protocol as a solution to overcome the network bottleneck, less flexible nodes, and more energy waste at the centralised wireless sensor networks (WSN). These problems are triggered by mechanism of choosing a centralised WSN coordinator to start communication and manage the resources. Unlike IEEE 802.11 standard, the IEEE 802.15.4 MAC protocol does not include method to overcome hidden nodes problem. Moreover, understanding the behaviour and performance of a large-scale WSN is a very challenging task. A comparative study is conducted to investigate the performance of the proposed ad hoc WSN both over the low data rate IEEE 802.15.4 and the high data rate IEEE 802.11 standards. Simulation results show that, in small-scale networks, ad hoc WSN over 802.15.4 outperforms the WSN where it improves 4-key performance indicators such as throughput, PDR, packet loss, and energy consumption by up to 22.4%, 17.1%, 34.1%, and 43.2%, respectively. Nevertheless, WSN achieves less end-to-end delay; in this study, it introduces by up to 2.0 ms less delay than that of ad hoc WSN. Furthermore, the ad hoc wireless sensor networks work well both over IEEE 802.15.4 and IEEE 802.11 protocols in small-scale networks with low traffic loads. The performance of IEEE 802.15.4 declines for the higher payload size since this standard is dedicated to low rate wireless personal access networks. A deep performance investigation of the IEEE 802.15.4 beaconless-enabled wireless sensor network (BeWSN) in hidden nodes environment has been conducted and followed by an investigation of network overhead on ad hoc networks over IEEE 802.11 protocol. The result of investigation evinces that the performance of beaconless-enabled ad hoc wireless sensor networks deteriorates as indicated by the degradation of throughput and packet reception by up to 72.66 kbps and 35.2%, respectively. In relation to end-to-end delay, however, there is no significant performance deviation caused by hidden nodes appearance. On the other hand, preventing hidden node effect by implementing RTS/CTS mechanism introduces significant overhead on the network that applies low packet size. Therefore, this handshaking method is not suitable for low rate communications protocol such as IEEE 802.15.4 standard. An evaluation study of a 101-node large-scale beaconless-enabled wireless sensor networks over IEEE 802.15.4 protocol has been carried out after the nodes deployment model was arranged. From the experiment, when the number of connection densely increases, then the probability of packet delivery decreases by up to 40.5% for the low payload size and not less than of 44.5% for the upper payload size. Meanwhile, for all sizes of payload applied to the large-scale ad hoc wireless sensor network, it points out an increasing throughput whilst the network handles more connections among sensor nodes. In term of dropped packet, it confirms that a fewer data drops at smaller number of connecting nodes on the network where the protocol outperforms not less than of 34% for low payload size of 30 Bytes. The similar trend obviously happens on packet loss. In addition, the simulation results show that the smaller payload size performs better than the bigger one in term of network latency, where the payload size of 30 Bytes contributes by up to 41.7% less delay compared with the contribution of the payload size of 90 Bytes.

The aim of the paper is showing, how projection methods can be used for computing contact problems in elasticity for different classes of obstacles. Starting with the projection idea for handling hanging nodes in finite element discretizations the extension of the method for handling penetrated nodes in contact problems will be described for some obstacle classes.

Magister Scientiae Dentium - MSc(Dent) / Tuberculosis is the world’s leading cause of death from a single infective agent. The World Health Organisation has declared the disease a “global emergency”. Extrapulmonary presentations form a major proportion of new cases, especially since the advent of the acquired immunodeficiency syndrome epidemic. Therefore, it is important that oral health care workers are aware of tuberculosis in the head and neck region and its varied manifestations. This study reports on one hundred and four patients diagnosed with tuberculosis and with head and neck tuberculosis lesions.The aim of the study was to determine the extent to which tuberculosis presents in the head and neck region. It was a descriptive, retrospective, record-based study on a cohort of tuberculosis patients that presented with head and neck tuberculosis at private practices in the Durban area over a fourteen month period. A structured data capture sheet was the method chosen for recording the data.The majority of the sample (89.4%) had tuberculosis of the head and neck lymph nodes, five (4.8%) had tuberculosis of the tonsil, two (1.9%) had tuberculosis of the larynx, two (1.9%) had tuberculosis of the ear, one (1%) had parotid gland tuberculosis and one (1%) had tuberculosis of the nose. The records indicate that excision biopsy and histopathological examinations were used to make a diagnosis. A third (33.7%) of the patients were confirmed with human immunodeficiency virus infection.A high index of suspicion of tuberculosis is important in the differential diagnosis of neck swellings, hoarseness and otorrhoea and in human immunodeficiency virus positive patients with an enlarging neck mass. A biopsy is usually necessary for diagnosis. Successful outcome depends upon appropriate chemotherapy and timely surgical intervention when necessary. Oral health care workers need to be fully cognizant of all the various presentations of head and neck tuberculosis to allow early diagnosis and quick commencement of appropriate treatment.

Studies on the health status of lions (Panthera leo) in the Kruger National Park (KNP) have revealed certain lions suffering from chronic debility (“poor doers”). Clinical signs include chronic emaciation, renal failure and chronic bacterial infections. The diagnosis of Mycobacterium bovis in KNP lions in 1995 raised the question of whether these “poor doer” lions were suffering from tuberculosis. Tests confirmed tuberculosis in some cases, but no aetiology for the poor condition was found in a large percentage of the animals tested. Extensive literature review failed to reveal reports of similar findings of chronic debility in free living lion populations, although various disease outbreaks and infectious diseases of lions are described. These are briefly reviewed. Surveys have confirmed that the majority of the KNP lions are serologically positive for feline immunodeficiency virus (FIV), the clinical importance of which is questioned as a possible cause of immunosuppression in lions. Tissue samples from eleven lions suffering from chronic debility and six clinically healthy lions were studied by light microscopy. Changes in the various organ systems were reported and tabulated with reference to degree and relevance. Frozen lymph node samples from some animals in both groups were collected for immunohistochemical staining for T and B lymphocytes and CD4 and CD8 subsets. In some cases serology was done for FIV using a Puma Lentivirus ELISA and a Puma Lentivirus Western Blot technique. Mycobacterial culture results were available for some animals. The histopathological features varied, but notable changes were seen in the lymph nodes. These included generalized lymphoid hyperplasia (predominantly affecting clinically healthy lions), progressing through combined hyperplasia and atrophy in different nodes to lymphoid atrophy affecting most of the lions suffering from chronic debility. These are non-specific findings seen in various systemic diseases, including canine distemper virus infection and toxoplasmosis, but they have also been described in domestic cats suffering from FIV infection and humans with HIV. Further findings in lymph node sections included mineral deposition and multifocal cystic spaces. Other important histopathological changes included chronic interstitial pneumonia, renal amyloidosis, chronic interstitial nephritis, Wallerian degeneration of the spinal cord, encephalomalacia and anterior uveitis. Two animals suffered from multifocal, multisystemic granulomatous inflammation. Mycobacterium bovis was cultured from one of these cases, but no apparent aetiology could be found in the other. Eosinophilia was a consistent finding in many tissues and most likely related to the high parasite load in many of the animals. Parasites found included Hepatozoon spp., microfilaria, cestodes, nematodes and trematodes and Sarcocystis spp. and Trichinella spp. Immunohistochemical staining for B and T lymphocytes and CD4 and CD8 subsets showed a normal distribution of the staining pattern within the lymph node sections, although the samples were all from FIV positive lions. The histopathology in both study groups was of a non-specific nature and not indicative of any particular disease syndrome, although many of the changes are similar to those described in domestic cats infected with FIV. There are indications of possible immunocompromise in the “poor doer” lions, which warrants further investigation. / Dissertation (MMedVet (Pathology))--University of Pretoria, 2006. / Oral Pathology and Oral Biology / unrestricted

This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.

Listeria monocytogenes is a facultative intracellular bacterium that causes foodborne disease in humans. L. monocytogenes invade the gut mucosa and then disseminate, causing systemic infections associated with high mortality rates in immunocompromised individuals. It is unknown how L. monocytogenes traffic to the mesenteric lymph nodes, which represent an important bottleneck for systemic spread. In addition, little is known about the gastrointestinal stage of infection due to the general resistance of mice to oral infection with L. monocytogenes. Our laboratory developed a novel foodborne mouse model of listeriosis utilizing a murinized strain of L. monocytogenes to investigate the gastrointestinal stage of infection. First, we found that the majority of L. monocytogenes isolated from the intestinal tissue and MLN were extracellular; however, the minimal fraction of intracellular L. monocytogenes was vital for persistence in the gut and spread to the MLN. The vast majority of cell-associated L. monocytogenes in the MLN were adhered to inflammatory monocytes, but these cells did not support the intracellular growth of L. monocytogenes. A minor proportion of L. monocytogenes were associated with migratory dendritic cells in the intestinal lamina propria and MLN, but like monocytes, these cells did not appear to serve as an intracellular growth niche for L. monocytogenes. Lastly, extracellular L. monocytogenes were observed migrating in mesenteric lymphatic vessels that drain from the intestine to the MLN, suggesting that L. monocytogenes can spread beyond the intestinal mucosa independent of migratory immune cells. Overall, these studies are the first to characterize the interaction of L. monocytogenes with immune cells in the intestine and MLN following foodborne infection and suggest that extracellular, and not cytosolic L. monocytogenes, primarily drive innate immune responses in the gut.

Over-the-air programming systems for wireless sensor networks have drawbacks that stem from fundamental limitations in the hardware used in current sensor nodes. Also, advances in technology make it feasible to use capacitors as the sole energy storage mechanism for sensor nodes using energy harvesting, but most current designs require additional electronics. These two considerations led to the design of a new sensor node. A microcontroller was chosen that meets the Popek and Goldberg virtualization requirements. The hardware design for this new sensor node is presented, as well as a preliminary operating system. The prototypes are tested, and demonstrated to be sustainable with a capacitor and solar panel. The issue of capacitor leakage is considered and measured.

O linfonodo é um órgão linfoide secundário que apresenta uma arquitetura altamente organizada com diferentes compartimentos para tipos celulares específicos. Dentre as células estruturais que compõem este órgão, as células estromais como células fibroblásticas reticulares (FRCs) e células duplo negativas (DNCs) parecem ter papel importante na modulação da resposta imunológica e na tolerância periférica. As FRCs são caracterizadas pela expressão de podoplanina (gp38, PDPN) e localizam-se principalmente na zona de células T, enquanto as DNCs (gp38-) apresentam fenótipo, localização e função pouco descritos. Embora estas células tenham sido muito estudadas em modelos murinos os estudos sobre FRCs e DNCs humanas são escassos e, portanto nosso estudo deve contribuir para a compreensão da biologia e a função dessas células, podendo favorecer o conhecimento sobre a eficiência e as disfunções da resposta imune no linfonodo. Com esse intuito, isolamos e caracterizamos fenotípica e funcionalmente as FRCs e DNCs de linfonodos de pacientes com câncer, diverticulite e doadores de fígado. Nossos resultados mostraram a integridade e a distribuição celular no linfonodo. As células aderentes derivadas dos linfonodos estudados preecheram todos os critérios internacionais de caracterização de estroma, e, portanto, foram consideradas células estromais. Através da expressão de gp38 identificamos duas subpopulações de celulas estromais: FRCs (gp38+ e CD31-) e DNCs (gp38- e CD31-) e verificamos que as frequências destas células variam entre as amostras, sugerindo que a doença pode interferir na composição celular estromal dos linfonodos. As duas populações celulares foram estimuladas com citocinas inflamatórias como IFN-y ou TNF-alfa + IL-1beta por 24 e 48 horas e avaliadas quanto à expressão gênica e proteica. Em condições homeostáticas, genes relacionados com a indução e controle da proliferação foram diferencialmente expressos nas FRCs e DNCs, este dado foi confirmado in vitro, uma vez que as FRCs apresentaram maior potencial proliferativo em relação às DNCs. O estímulo com IFN-y induziu aumento de expressão nas DNCs e FRCs para citocinas, quimiocinas, moléculas de histocompatibilidade e moléculas envolvidas na regulação da resposta imunológica. Em resposta ao estímulo com TNF-alfa +IL-1beta, observamos aumento na expressão de moléculas comuns ao estímulo com IFN-?, entretanto, também observamos expressão de moléculas de citocinas, quimiocinas inflamatórias e moléculas de histocmpatibilidade especificamente relacionados a este sinal em ambas as populações. Em conjunto, nossos dados sugerem que DNCs e FRCs apresentam diferenças no perfil de resposta segundo os estímulos inflamatórios aos quais estão expostas, aumentando a expressão diferencial de moléculas envolvidas na regulação positiva e negativa da resposta imune / The lymph node is a secondary lymphoid organ that has a highly organized architecture with different compartments for specific cell types. Among the structural cells that comprise this organ, stromal fibroblastic reticular cells (FRCs) and double negative cells (DNCs) seems to play an important role in modulating the immune response and peripheral tolerance. FRCs are characterized by podoplanin (gp38, PDPN) expression and are located mainly in the T cell zone, while DNCs (gp38-) present phenotype, location and function not well described. Although these cells have been studied in murine models, studies on human FRCs and DNCs are limited and therefore our study should contribute to the understanding of biology and function of these cells and should promote knowledge of efficiency and disorders in the lymph node immune response. For this purpose, we have isolated and characterized phenotypic and functionally lymph nodes derived FRCs and DNCs from patients with cancer, diverticulitis and liver donors. Our results showed lymph node integrity and its cellular distribution. Adherent cells lymph nodes-derived fullfill the international criteria for stroma characterization, and therefore, they have been considered stromal cells. Using gp38 expression we were able to identify two stromal cells subpopulations: FRCs (gp38 + and CD31-) and DNCs (gp38- and CD31-) and found that this cells frequency varies among samples, suggesting that the disease may interfere with lymph nodes stromal cell composition. These two cells populations were stimulated with inflammatory cytokines such as IFN-y or TNF-alfa + IL-1beta for 24 and 48 hours and evaluated for gene and protein expression. In homeostatic conditions, genes involved in the induction and control of proliferation were differentially expressed by FRCs and DNCs, this data has been confirmed in vitro, since the FRCs showed higher proliferative potential compared to DNCs. IFN-y stimulation induced increase DNCs and FRCs expression for cytokines, chemokines, histocompatibility molecules and molecules involved in regulating the immune response.In response to TNF-alfa + IL-1beta stimulation, we observed common molecules expressed by the IFN-? stimulation, however, we also observed expression of cytokines, chemokines and histocompatibility molecules specifically related to this signal in both cells populations. Together, our data suggest that DNCs and FRCs differ in the response profile according to inflammatory stimuli to which they are exposed, increasing the differential expression of molecules involved in the positive and negative regulation of immune response

Orientador: Maria Jaqueline Mamprim / Resumo: A leishmaniose visceral canina geralmente acomete órgãos do sistema mononuclear fagocitário, entretanto, há evidências de que possa lesionar outros órgãos. Pouco se sabe sobre a patogenia da doença na cavidade torácica. Ainda não há descrições radiológicas das alterações torácicas de cães leishmanióticos. O presente estudo realizou avaliação tomográfica em 35 cadáveres de cães positivos e sintomáticos para a doença. Foi possível confirmar linfadenomegalia esternal e visibilizar os linfonodos mediastinais e traqueobrônquicos. Todos os animais apresentaram opacificações do tipo vidro fosco no parênquima pulmonar. Também se observaram opacificações do tipo linear, nodular e banda parenquimal nos pulmões e, ainda, espessamento e dilatação brônquica. A análise histopatológica foi realizada em 13 pulmões e revelou infiltrado inflamatório em diferentes graus, edema, congestão, espessamento de septo alveolar e brônquios congestos. Tais alterações tomográficas e histopatológicas são semelhantes às descritas em humanos. A tomografia computadorizada se mostra uma ferramenta de grande valia para avaliação da cavidade torácica de cães acometidos pela leishmaniose visceral. O acometimento torácico pela leishmaniose visceral canina deve ser considerado em diagnósticos diferenciais quando se observam opacificações do tipo vidro fosco e lineares e linfadenomegalia em exames tomográficos do tórax de cães em áreas endêmicas. / Abstract: Canine visceral leishmaniasis usually affects organs of the mononuclear phagocytic system, however, there is evidence that it can damage other organs. Little is known about the pathogenesis of the disease in the chest cavity. There are still no radiological descriptions of the thoracic changes in leishmaniotic dogs. In this study computed tomography in 35 cadavers of dogs positive and symptomatic for the disease was performed. It was possible to confirm sternal lymphadenomegaly and to visualize the mediastinal and tracheobronchial lymph nodes. All animals presented ground-glass opacifications in the lung parenchyma. Linear, nodular and parenchymal band opacifications were also observed in the lungs, as well as bronchial thickening and dilation. Histopathological analysis was performed in 13 lungs and revealed inflammatory infiltrate in different degrees, edema, congestion, thickening of the alveolar septum and congested bronchi. Such tomographic and histopathologic changes are similar to those described in humans. Computed tomography is a valuable tool for assessing the chest cavity of dogs affected by visceral leishmaniasis. Thoracic involvement by canine visceral leishmaniasis should be considered as differential diagnoses when ground-glass and linear opacifications and lymphadenomegaly are observed in tomographic examinations of the chest of dogs in endemic areas. / Doutor