published_or_final_version / Zoology / Master / Master of Philosophy

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This investigation was concerned with the relationship of the slime layer material of Pseudomonas aeruginosa, Verder and Evans strain 1369, to the presumably somatic "O" type of antigen used by these authors as the base for their serological schema.

Small carnivores and middle-sized mammals (mesomammals) are ubiquitous in fossil sites in South Africa, but their taphonomy is poorly understood. This study presents an actualistic investigation of bone modification by two captive small carnivores; the caracal (Caracal caracal) and honey badger (Mellivora capensis), housed at the Johannesburg Zoo. The carnivores were fed domestic rabbit (Oryctolagus cuniculus) carcasses as proxies for mesomammals and the bone modification of the resulting refuse and scatological assemblages were assessed in terms of their skeletal part representation, breakage patterns, digestive modifications and tooth marks. The investigation revealed that skeletal part representation and breakage patterns in the caracal and honey badger assemblages resembled those reported from other small carnivores. The caracal and honey badger assemblages were distinct from other carnivores in having overall light digestive modifications and a high frequency of tooth marks. Digestion was greater and tooth marks less frequent in the caracal than in the honey badger. Results were applied to the fossil assemblage of Cooper’s D which has a large assemblage of mesomammals and small carnivores. While a taphonomic analysis of Cooper’s D has not been published, initial results suggest that small carnivores had a great potential as contributors in the formation of the assemblage. The findings of this study emphasise the need for employing a variety of bone modifications in the identification of a small carnivore as an accumulator since there is rarely a single characteristic that is diagnostic for a particular carnivore.

Orientador: Ana Liz Garcia Alves / Banca: Luiz Carlos Vulcano / Banca: Vania Maria Vasconcelos Machado / Banca: Stefano Carlo Filippo Hagen / Banca: Debora Aparecida Pires de Campos Zuccari / Resumo: Este estudo teve por objetivo analisar os efeitos da aplicação de ondas de choque extracorpóreas na placa epifisária proximal da tíbia em coelhos. Foram utilizados 10 coelhos jovens, submetidos a três aplicações de 1500 pulsos de ondas de choque,com intervalo de duas semanas, sobre a epífise proximal da tíbia direita, padronizando a esquerda como controle. As avaliações foram feitas por meio de radiografias, para verificar as alterações na densitometria óptica óssea. Ao final do experimento foi feita a absorciometria de energia dupla de Raios-x (DXA) e eutanásia para a colheita de material para histopatologia e imuno-histoquímica para TGF- , possibilitando a comparação entre os membros tratados e os membros controle. As ondas de choque extracorpóreas causaram um aumento na espessura da placa de crescimento epifisária, tanto na espessura total, quanto na espessura das zonas proliferativa e hipertrófica, uma diminuição do comprimento das tíbias tratadas, em relação ao controle, e o aumento de densidade mineral óssea, ao utilizar a avaliação por meio da densitometria óptica em imagem radiográfica. / Abstract: The aim of this study was to evaluate the effects of the extracorporeal shock wave therapy on the tibial proximal epiphyseal growth plate in young rabbits. Ten rabbits were submitted to extracorporeal shock wave therapy in the right tibial proximal epiphyseal growth plate, three treatments, with interval of two weeks. The left hind limb was untreated as control. The evaluations were done through x-rays and optical densitometry, and at the end of the study dual energy x-ray absorptiometry evaluation, histopathology and immunohistochemistry evaluation for TGF- were done. Extracorporeal shock wave therapy caused increased height of the epyphiseal growth plate, reduction on tibial total length and increased bone mineral density evaluated through optcal radiographic densitometry in mmAl. / Doutor

A espécie leporina vem sendo utilizada de forma ampla como modelo experimental em diversas áreas da medicina e medicina veterinária. A escassez de estudos publicados nesta área torna questionável a utilização ética da espécie em experimentos cirúrgicos. O objetivo foi determinar a duração dos bloqueios motor e sensitivo da lidocaína e bupivacaína administradas pela via peridural sacrococcígea e lombossacra e seus efeitos cardiovasculares e respiratórios associados a anestesia geral inalatória em coelhos submetidos a orquiectomia. Foram utilizados 30 animais da espécie leporina, raça Nova Zelândia Branco, pesando entre 2,350 e 3,300 kg, distribuídos em cinco grupos experimentais. O grupo Lido LS recebeu 0,3 ml/kg de lidocaína a 2% pela via peridural lombossacra; o grupo Lido SC recebeu 0,3 ml/kg de lidocaína a 2% pela via peridural sacrococcígea; o grupo Bupi LS recebeu 0,3 ml/kg de bupivacaína a 0,5% pela via peridural lombossacra; o grupo Bupi SC recebeu 0,3 ml/kg de bupivacaína a 0,5% pela via peridural sacrococcígea e o grupo Controle recebeu 0,3 ml/kg de solução fisiológica pela via peridural lombossacra. A administração peridural foi realizada por meio de punção simples com agulha hipodérmica. Na primeira parte do experimento, os animais foram anestesiados com sevofluorano em oxigênio a 100% com auxílio de máscara, e após a administração do protocolo de cada grupo, os reflexos sensitivos foram testados por meio de pinçamento dos dermátomos cutâneos e dos dígitos dos membros pélvicos e cauda. Os reflexos motores foram avaliados por meio de escore de tônus muscular dos membros pélvicos e cauda. Esta fase teve como objetivo determinar a duração e padrão de dispersão do bloqueio sensitivo e motor. Duas semanas após a determinação da duração do bloqueio sensitivo e motor, os animais foram anestesiados com isofluorano em máscara, intubados, e a administração do mesmo protocolo de anestesia peridural foi realizada para a realização de orquiectomia. A frequência cardíaca, frequência respiratória, pressão arterial sistólica, média e diastólica, concentração de dióxido de carbono ao fim da expiração, concentração de isofluorano inspirado e expirado, saturação de oxihemoglobina e temperatura corpórea foram monitorados a cada 10 min durante 50 min. Logo após a administração peridural e ao fim do procedimento, uma amostra de sangue arterial foi colhida para avaliação hemogasométrica. A dispersão, avaliada pelo número de dermátomos bloqueados, nos grupos que receberam a administração lombossacra foi maior que nos grupos de administração sacrococcígea. O período médio de bloqueio sensitivo com a lidocaína foi de 70±13,78 min pela via lombossacra e 60,83±23,11 min pela via sacrococcígea. Com a administração de bupivacaína pela via lombossacra, a duração do bloqueio sensitivo foi de 199,16±15,30 min e pela via sacrococcígea foi de 168,33±44,57 min. O grupo controle teve maior consumo de anestésico geral e maior requerimento de analgésico trans-operatório e de fármacos vasoativos durante o procedimento, demonstrando analgesia insuficiente e depressão cardiovascular superior aos grupos em que houve a associação da anestesia peridural e geral. Houve ocorrência de bloqueio unilateral em 50 % dos animais que receberam a administração sacrococcígea. Conclui-se que a administração peridural lombossacra apresentou duração e dispersão maiores que a administração sacrococcígea em coelhos. A ocorrência de bloqueio unilateral foi maior com a utilização do sítio sacrococcígeo. Foi observada maior depressão cardiovascular nos animais que não receberam a administração de anestésico local no espaço epidural. A utilização de lidocaína e bupivacaína levou a anestesia peridural satisfatória na espécie leporina, sendo uma técnica eficiente e de fácil execução. / Rabbits have been widely used as an experimental model in different areas of medicine and veterinary medicine. The few published studies in this area make the ethical use of this species in surgical experiments questionable. The aim of this study was to determine the duration of sensory and motor block of lidocaine and bupivacaine epidurally administered in lumbosacral or sacrococcygeal sites and their cardiovascular and respiratory effects associated with inhalation anesthesia in rabbits undergoing orchiectomy. Thirty New Zealand White rabbits were used, weighing between 2,350 and 3.300 kg, divided into 5 experimental groups. The Lido LS group received 0.3 ml / kg of 2% lidocaine lumbosacral epidural; Lido SC group received 0.3 ml / kg of 2% lidocaine sacrococcygeal epidural; Bupi LS group received 0.3 ml / kg of 0.5% bupivacaine for lumbosacral epidural; Bupi SC group received 0.3 ml / kg of 0.5% bupivacaine for sacrococcygeal epidural; and the control group received 0.3 ml / kg of saline epidural lumbosacral. Epidural was performed by single puncture with hypodermic needle. In the first part of the experiment, the animals were anesthetized with sevoflurane in 100% oxygen mask, and after the administration of each protocol group, the sensitive reflexes were tested by pinching the skin dermatomes and the digits of the hind limbs and tail. The motor reflexes were evaluated by scoring muscle tone of the pelvic limbs and tail. Two weeks after the determination of the duration of sensory and motor block, the animals were anesthetized with isoflurane in mask, intubated, and the administration of the same protocol of epidural anesthesia was performed for the orchiectomy. Heart and respiratory rate, systolic, mean and diastolic arterial blood pressure, end-tidal CO2, concentration of isoflurane inhaled and exhaled, oxyhemoglobin saturation and body temperature were monitored every 10 minutes during a 50 minutes surgery. Soon after epidural administration and at the end of the procedure, a sample of arterial blood was collected for evaluation of arterial blood gases. The dispersion was measured by the number of dermatomes blocked and groups receiving lumbosacral administration had a higher number than groups that received sacrococcygeal administration. The mean duration of sensory block with lidocaine was 70±13.78 min via lumbosacral site and 60.83±23.11 min via sacrococcygeal site. In bupivacaine lumbosacral group, the duration of sensory block was 199.16±15.30 min and in sacrococcygeal group was 168.33±44.57 min. The control group had higher consumption of general anesthetic and trans-operative analgesic requirement and had higher vasoactive requirement during the surgical procedure, demonstrating greater cardiovascular depression than the groups that received an association of epidural and general anesthesia. There was 50% occurrence of unilateral block in animals that received the sacrococcygeal administration. It is concluded that epidural administration showed lumbosacral length and dispersion greater than sacrococcygeal administration in rabbits. The incidence of unilateral block was higher when used the sacrococcygeus site. Greater cardiovascular depression was observed in animals that did not receive the administration of local anesthetic into the epidural space. The use of lidocaine and bupivacaine led to satisfactory epidural anesthesia in rabbits, being an efficient and easy technique to perform.

Pantethine, a precursor of coenzyme A, has been shown to reduce serum cholesterol levels in hypercholesterolemic rabbits. The enzyme pantetheinase rapidly hydrolyzes pantethine to the vitamin pantothenic acid and the amino thiol cysteamine. This study was designed to compare the effect of cysteamine and pantothenate supplementation with that of pantethine on hypercholesterolemic rabbits. New Zealand white rabbits were fed a 0.5% cholesterol diet for 5 weeks; treatment groups received only the high cholesterol diet (control), or a high cholesterol diet supplemented with 1% pantethine, or an equimolar amount of pantothenic acid or cystamine (the disulfide of cysteamine). Blood samples were drawn weekly and total serum cholesterol levels analyzed enzymatically. Pantethine and cystamine both significantly reduced serum cholesterol levels (p < 0.05); pantothenic acid had no effect. Separation of serum lipoproteins using a preparative ultracentrifuge showed an increase in very low density, intermediate density and low density lipoproteins. A second experiment was conducted to compare the effect of cystamine with other small thiols; the protocol was similar to the first experiment with treatment groups consisting of a high cholesterol control, cystamine, cystine or 2,hydroxyethyl disulfide. There was no significant reduction in serum cholesterol levels between treatment groups, although the cystamine supplemented group tended to be lower than the other groups.

The experiments described in this thesis examined post-extinction recovery phenomena following classical conditioning in the rabbit. The first series of experiments examined the rate of reacquisition to the original conditioned stimulus (CS) and to a cross-modal CS following various amounts of extinction. In both the rabbit nictitating membrane (NM) preparation and rabbit heart rate (HR) conditioning, there was a graded reduction in the rate of reacquisition as a direct function of the number of extinction trials. In the rabbit NM preparation, there was also a graded reduction in the rate of acquisition to a cross-modal stimulus (CSB, e.g., light). However, concurrent recovery of responding to the original, extinguished stimulus (CSA, e.g., tone) during training with a novel, cross-modal stimulus (CSB, e.g., light), appeared uniformly robust even following extensive extinction. The second series of experiments examined the conditions necessary for concurrent recovery to occur in the rabbit NM preparation. The introduction of CSB-US pairings resulted in strong recovery of responding to CSA, while the reintroduction of the US alone failed to result in any discernable reinstatement of responding to CSA. Concurrent recovery was specific to the trained and extinguished CSA, with virtually no generalized responding to a novel cross-modal test stimulus (CSC). However, pretraining with CSB-US pairings significantly reduced the amount of recovery to CSA during subsequent CSB???US pairings. The third series of experiments revealed that concurrent recovery was specific to the extinguished stimulus (CSA) with only moderate generalization to other familiar but untrained stimuli in the same modality as CSA. Together these results indicate that concurrent recovery is not primarily the result of the unmasking of the original CSA-US association. Rather, concurrent recovery appears to be at least partially the result of learning-dependent generalization. However, in order for responding to CSB, to generalize to CSA, CSA must have been paired with the same US which is subsequently paired with CSB. Thus, the CSA-US association must be partially intact for concurrent recovery to occur. A layered network model with multiple hidden units is able to simulate rapid reacquisition, facilitated cross-modal acquisition and concurrent recovery.

Abstract not available

Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 60-71).