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Cheng, Winston Teng-Kuei. "In vitro fertilization of farm animal oocytes." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354475.
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Cal, Josy Alvarenga. "Histologia do trato digestório do surubim-pintado (Pseudoplatystoma coruscans - Agassiz, 1829)." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-01032007-180235/.
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O pintado (Pseudoplatystoma coruscans), também comumente chamado de surubim é um dos peixes mais apreciados pelo mercado consumidor brasileiro, devido à excelente qualidade do filé. No entanto, trabalhos sobre a morfologia do seu trato digestório são escassos. No presente trabalho, a descrição histológica do esôfago, estômago e intestino do pintado, visa contribuir e fornecer subsídios científicos para compreensão dos processos digestivos dessa espécie. Foram obtidas amostras do esôfago, estômago e de todas as regiões intestinais e posteriormente analisadas à microscopia óptica. No esôfago, observou-se epitélio de revestimento do tipo pavimentoso estratificado não-queratinizado, apresentando células epiteliais, mucosas e grande quantidade de células claviformes. A presença de células claviformes são indicadores de que este órgão está sujeito a lesão e lacerações, participando no sistema de defesa do organismo. O estômago do pintado constitui-se de um órgão em forma de J, distinguindo-se três regiões: cárdica, fúndica e pilórica. O epitélio de revestimento encontrado é do tipo colunar simples. A superfície epitelial é interrompida pelas criptas gástricas, no fundo das quais se abrem as glândulas gástricas, sendo estas criptas mais profundas na região cárdica ou proximal do estômago. As glândulas gástricas apresentam-se maiores e mais numerosas no segmento proximal, diminuindo em quantidade e tamanho no sentido caudal, o que está relacionado a uma maior demanda na secreção de muco para proteção e digestão de proteínas. O intestino do pintado constitui-se de três regiões distintas e denominadas: intestino proximal, intestino médio e intestino distal ou reto. No epitélio intestinal foram encontrados macrófagos e linfócitos indicando uma barreira celular de defesa no organismo. No intestino distal, observou-se epitélio com cutícula estriada mais baixa do que nos segmentos anteriores. Podemos concluir que o pintado apresenta características particulares quanto à estrutura microscópica do seu trato digestório, em alguns aspectos, se comparado a outros teleósteos.<br>Pintado (Pseudoplatystoma coruscans), also commonly called surubim, is one of the most appreciated fish by the Brazilian consumer market, due to the excellent filet quality. However, works on the morphology of their digestive tract are scarce. In this work, the histological description of the esophagus, stomach and intestine of pintado, seeks to contribute and to supply scientific information for the better understanding of the digestive process of these species. Samples were obtained from esophagus, stomach and from all the intestinal areas and later analyzed with light microscope. In the esophagus, epithelium is stratified pavimentous type and was observed no queratinization, presenting epithelial cells, mucous membranes and great amount of club cells. The presence of club cells indicates that this organ is subjected to lesion and lacerations, participating in the organism defense system. The stomach of pintado is constituted of an organ in J form, being there distinguished three areas: cardic, fundic and piloric. The epithelium of the stomach is simple colunar type. The epithelial surface is interrupted by the gastric crypts, in the bottom of which opens up the gastric glands, being these deeper crypts in the cardic area or proximal of the stomach. The gastric glands come larger and more numerous in the proximal segment, decreasing in amount and size in the caudal way, what is related to a larger demand in the mucus secretion for protection and digestion of proteins. The pintado`s intestine is constituted of three different areas and denominated: proximal intestine, medium intestine and distal intestine or rectum. In the intestinal epithelium there were found macrophages and lymphocytes indicating a cellular barrier for the organism defense. In the distal intestine, epithelium was observed with cuticle grooved lower than in the previous segments. We can conclude that pintado presents private characteristics in relation to the microscopic structure of its digestive tract, in some aspects, if compared to other teleosts.
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Fonsêca, Vitor Cortizo da. "Estudo morfométrico da retina de ratos expostos agudamente à fumaça de cigarro." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/5/5149/tde-17102014-101523/.
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Objetivo: Estudar as alterações morfométricas da retina de ratos expostos agudamente à fumaça de cigarro. Métodos: Em um estudo experimental, controlado, mascarado, foram utilizados 24 ratos Wistar machos (8 semanas de idade), sendo metade deles expostos por duas horas contínuas à fumaça de cigarro em uma câmara de inalação e a outra metade exposta a ar comprimido como grupo controle. A fumaça foi aspirada diretamente do cigarro utilizando um sistema venturi, e conduzida para a câmara. A concentração de monóxido de carbono no interior da câmara de inalação foi mantida em uma faixa constante de 45 a 55 partes por milhão, monitorada eletronicamente no interior do recipiente. Os ratos foram sacrificados imediatamente após a inalação e nos momentos 24 e 48 horas após exposição. Os olhos foram enucleados e analisados por meio da morfometria em microscópio óptico, por examinador mascarado. Resultados: Foram identificadas regiões da retina do grupo exposto que sofreram redução das estimativas morfométricas em comparação ao grupo controle, com significância estatística correspondendo às regiões dos fotorreceptores, camada nuclear interna e plexiforme interna 48 horas após a exposição. Comparando os grupos expostos entre si houve uma redução progressiva nas estimativas morfométricas das camadas retinianas com o aumento do intervalo entre o término da exposição e o sacrifício, de forma estatisticamente significante na camada nuclear interna. Conclusão: As retinas dos ratos expostos agudamente à fumaça de cigarro sofreram uma redução nas estimativas morfométricas, com uma tendência a redução progressiva nas estimativas no decorrer das primeiras 48 horas após exposição<br>Objective: To evaluate morphometric alterations of the retina, from rats acutely exposed do cigarette smoking. Methods: In an experimental, prospective, masked study with 24 male Wistar rats (8 weeks old), half of them were exposed during two hours continually to cigarette smoking inside an intoxicating chamber, while the other half exposed to compressed air. The smoke was aspirated directly from cigarette, using a venturi system, and conducted to the chamber. The carbon monoxide concentration was constantly kept in between 45 to 55 parts per million, electronically monitored inside de chamber. The rats were sacrificed immediately after the inhalation, 24 and 48 hours after exposition. The eyes were enucleated and analyzed trough morphometry, in an optical microscope, by a masked examiner. Results: It was identified regions of the retina in the experimental group that suffered a reduction in the morphometric estimates, comparing to control group, with statistical significance, corresponding to the photoreceptor layer, the inner nuclear and inner plexiform layers, 48 hours after exposure. Comparing the exposed groups between themselves, there was a progressive reduction in the morphometric estimates of retinal layers after an increase in time between finishing the exposure and sacrifice, with statistical significance in inner nuclear layer. Conclusion: The retina of rats acutely exposed to cigarette smoke suffered a reduction in the morphometric estimates, with a tendency to progressive reduction in the estimates during the initial 48 hours after exposure
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Godoy, Montanez R. H. "Rumen fermentation and blood metabolites in animals fed diets based on molasses." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372932.
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Pereira, Simone Machado. "Morfologia dos órgãos genitais masculinos do tucuxi amazônico (Sotalia fluviatilis)." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-08072008-103909/.
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Sotalia fluviatilis é o único Delphinidae que ocorre em água doce, sendo endêmico da região amazônica. É considerada pela IUCN como espécie insuficientemente conhecida (dados deficientes), estando incluída no Apêndice I da CITES como espécie ameaçada de extinção. Atualmente, vem sendo alvo de caça ilegal para utilização como isca na pesca de um bagre, conhecido como piracatinga. Sendo assim, toda medida para melhor compreensão da biologia desta espécie é de suma importância para assegurar medidas eficazes de conservação no futuro. Neste trabalho foi realizada a descrição morfológica dos órgãos genitais masculinos do tucuxi, através de analises de amostras provenientes dos acervos do Instituto de Desenvolvimento Sustentável Mamirauá e do Instituto de Pesquisas da Amazônia. Estas foram analisadas através de técnicas macroscópicas, de microscopia óptica e de microscopia eletrônica de varredura. Os órgãos genitais masculinos do tucuxi são compreendidos por grandes testículos e epidídimos típicos, presos à cavidade abdominal pelo mesórquio. Os ductos deferentes são convolutos nas regiões proximais e retos nas suas poções distais, possuindo um pequeno útero masculino entre eles. A próstata é pequena e compacta, coberta pelo músculo compressor da próstata, e envolve toda a uretra pélvica. O pênis é fibroelástico, possuindo uma flexura sigmóide em espiral e a extremidade livre afilada. Os pilares do pênis estão inseridos em pequenos ossos pélvicos, sendo que associados à raiz do pênis estão os músculos isquiocavernoso, bulboesponjoso e retrator do pênis. Em geral, a estrutura macro e microscópica, a localização e a função destes órgãos é semelhante à outras espécies da Ordem Cetacea, com exceção de alguns detalhes.<br>Sotalia fluviatilis is endemic in Amazon region and the only Delphinidae living in freshwater. It is considered by IUCN as an insufficiently known specie (deficient data) and is included in CITES Appendices I as a threatened specie. Additionally, this species is currently hunted and used as bait for fishing practices of a catfish called piracatinga. Thus, all efforts directed toward understanding the biology of this animal are important and may help to implement future conservation strategies. In the present study, samples of males tucuxi\'s genital organs provided by Instituto de Desenvolvimento Sustentável Mamirauá and Instituto de Pesquisas da Amazônia were analyzed by gross and microscopic techniques and by scanning electron microscopy. The male tucuxi\'s genital organs are represented by big testes and a typical epididymis that is adhered to the abdominal cavity wall by the mesorchium. The ductus deferens are convoluted in the proximal region and straight in the distal portion, and a small uterus masculinus is located between them. The prostata is small, compact, covered by the prostate compressor muscle, and totally involves the pelvic urethra. The penis is fibroelastic and characterized by a spiral sigmoid flexure that ends in a tapering cone. The crura are inserted on small pelvic bones, and the ischiocavernosus, bulbospongiosus and retractor penis muscles are associated to the base of the penis. In general, the structure, location and function of these organs are similar to other Cetacea species, except about some details.
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Parkinson, Christopher. "The use of cell cultures as an alternative to live animals in acute fish toxicity testing." Thesis, Kingston University, 1988. http://eprints.kingston.ac.uk/20348/.
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The toxicity of various chemicals was investigated in vitro and in vivo in carp ('Cyprinus carpio') and tilapia ('Oreochromis spilurus'). In order to study tilapia in vitro it was necessary to establish and characterise a cell line. A fibroblastic cell line, called TSB cells was derived tilapia brain. A cytotoxicity assay was devised utilising cultures of EPC cells (of carp epithelioma origin) and TSB cells. The effects of the test chemicals were assessed quantitatively by protein assay or lysosomal uptake of Neutral Red dye, and subjectively by light microscopy. The in vivo toxicities of the same chemicals were studied in static 96h LC[sub]50 bioassays. The responses by carp and tilapia to the effects of the chemicals were recorded. In addition, histopathological examination was carried out on a number of tissues of fish employed in the LC[sub]50 tests. From these examinations, further information as to the nature of toxicity caused by each chemical in carp and tilapia was produced. Correlations between in vitro and in vivo acute toxicities were generally good, although the in vitro assays lacked comparable sensitivity. It is therefore not possible at this stage to adequately replace live animals with cell cultures in toxicity testing. However, the results obtained here clearly establish that the use of cell cultures in toxicity assessment programmes could lead to a reduction in the numbers of fish being used. This investigation has also clearly identified the avenues future research has to explore if the use of live fish is to be minimised.
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Oliveira, Roselaine Ponso de. "Estudo do membro pélvico do avestruz: considerações anatômicas, radiográficas e histológicas da rotação tibiotársica." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-23062006-140034/.
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Várias doenças músculo esqueléticas foram observadas em aves de rápido crescimento, sendo o elevado peso corporal, associado a uma estrutura óssea em formação, citados como as principais causas responsáveis pela ocorrência destas doenças, resultando em disfunções do aparelho locomotor. Apesar do estudo do membro pélvico do avestruz merecer a atenção de pesquisadores desde o século XIX, tendo sido descrito no tocante à miologia, principalmente, a osteologia e o estudo radiográfico e morfológico envolvidos na RTT ainda não receberam a devida atenção. O presente trabalho teve como objetivo fazer um estudo anátomo-patológico e radiográfico das estruturas envolvidas na rotação tibiotársica, assim como estudar as alterações articulares através de artrografias e histologia fazendo uma descrição das considerações anatômicas, macroscópicas, microscópicas e radiográficas do membro pélvico do avestruz (African Black). Para este estudo foram utilizadas trinta avestruzes, com idade entre um mês a um ano de idade, apresentando deformidade de membros pélvicos uni ou bilateral. Dessa forma, será possível contribuir para o entendimento desta enfermidade, que tem causado perdas para a estrutiocultura.<br>Ostrich?s hind limbs study: Anatomical, radiographic and histological considerations of the tibiotarsus rotation. Many skeletal muscles diseases were observed in fast growth, been the hight body wight, to associate with a bone structure in formation citads with the principal responsible cases for ocorrence these deseases, have been disfunction of locomotor arrangment. Despite the fact that the ostrich?s hind limbs have deserved attention from researchers since the 19th century, the myological and osteological descriptions together with the radiographic and morphological study, which involves RTT, have not received any attention yet. This present research intends to make an anatomical, pathological and radiographic study of the structures involved in the tibiotarsus rotation, besides the study of the joint alterations by arthrography and histology, giving one description with anatomical, macroscopic, microscopic and radiographic considerations of the ostrich?s hind limbs. This way, it?ll be possible to contribute to the comprehension of this disease that has caused many losses on the ostrich farm.
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Saviani, Gisele. "Distribuição anatômica e histológica dos componentes do tecido linfóide ao longo do intestino de avestruz (Struthio camelus)." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/10/10132/tde-22062006-135534/.
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O avestruz (Struthio camelus), embora compartilhe de muitas adaptações evolucionárias de outros pássaros, possui algumas características anatômicas relacionadas com o seu tubo digestivo que são únicas, entre as quais podemos citar o cólon que se apresenta maior que o ceco (aparece duplicado) . Há algum tempo esta ave têm sido explorada economicamente, principalmente na alimentação como uma carne alternativa para o consumo humano. O presente trabalho tem como objetivo estudar as estruturas anatômicas e histológicas do intestino ligadas a distribuição do tecido linfóide . No estudo foram utilizados vinte e quatro avestruzes, com idade entre 2 meses e 2,5 anos, sendo animais destinados ao abate. Para a descrição morfológica utilizou-se a metodologia preconizada Bezuindenhout (1986) e o método de rotina para coloração hematoxilina e eosina. Esperamos contribuir na multiplicação de conhecimentos na área da estrutiocultura.<br>Although the ostrich shares a lot of evolutionary adaptation with other birds, it presents some anatomical characteristics concerning its digestive tube that are unique, like the colon for instance. The ostrich?s colon is bigger than its caecum. The caecum is doubled. The caecum is folded. This bird has been economically exploited, mainly because of its meat as an alternative food for humans. The purpose of the present research is to study the anatomical and histological structures connecting them to the lymphoid tissue distribution. In this study, 24 ostriches between the ages of 2 months and 2 years and a half ? when they?re ready to be slaughtered ? were used. In order to describe the study, the Bezuindenhout methodology and the routine method for printing H. E. and eosine were used.
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Margarido, Clarita Bandeira. "Efeitos pulmonares da hemodiluição normovolêmica aguda com hidroxietilamido ou ringer lactato em porcos." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/5/5152/tde-06102014-111712/.
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Introdução: A hemodiluição normovolêmica aguda (HNA) é estratégia utilizada para diminuir a necessidade de transfusão em procedimentos cirúrgicos. O hematócrito alvo, a solução empregada e os riscos da HNA são controversos e, embora as ações sobre os sistemas nervoso e cardiocirculatório tenham sido extensamente pesquisados, há poucos estudos sobre implicações pulmonares da HNA. O objetivo deste estudo é avaliar os efeitos pulmonares da HNA comparando amido hidroxietílico e Ringer lactato. Métodos: Vinte e cinco porcos foram monitorizados e cateterizados. Utlizou-se anestesia intravenosa contínua com propofol, cetamina, fentanil e pancurônio. Após estabilização da anestesia, os animais foram randomizados: Grupo Controle (n=8), Grupo HES (amido hidroxietílico, n=7) e Grupo RL (Ringer lactato, n=10). Os animais dos grupos II e III foram submetidos a HNA até hematócrito pré-estabelecido de 15%. A retirada do sangue foi acompanhada da expansão plasmática com amido hidroxietílico ou Ringer lactato na proporção de 1:1 ou 3:1 respectivamente. Medidas de mecânica respiratória e oxigenação sangüínea foram realizadas antes da retirada de sangue (T0), ao término da hemodiluição (T1) e após uma e duas horas (T2 e T3). Ao final foram realizadas biópsias pulmonares. Os dados foram submetidos à análise de variância para medidas repetidas (ANOVA) seguidas pelo teste de Tukey. Resultados: Em relação aos parâmetros do grupo controle, não houve diferença significante durante todo o procedimento. O grupo Ringer lactato demonstrou diminuição da complacência estática e aumento da diferença alvéolo-arterial de O2 (DAa-O2) em relação ao controle (*P<0,05). A análise histopatológica evidenciou atelectasias e alargamento da membrana basal na barreira alvéolo-capilar no grupo Ringer lactato. O grupo amido hidroxietílico apresentou comportamento semelhante ao grupo controle. Conclusões: O estudo sugere que na HNA acentuada, o amido hidroxietílico é superior na preservação estrutural do pulmão, evidenciado pormanter a complacência pulmonar e a oxigenação, quando comparada à realizada com solução de Ringer lactato<br>Introduction: Acute normovolemic hemodilution (ANH) is a common procedure to decrease the needs of blood transfusion during a variety of surgical procedures. There are controversies regarding ANH such as the target hematocrit, the solution to be used and its risks. Although its effects in heart and brain have been extensively studied; investigations concerning its pulmonary effects are lacking. The aim of this experiment was to compare the pulmonary effects of ANH with hydroxyethyl starch and lactated Ringer\'s. Methods: Twenty five pigs were instrumented for standard hemodynamic monitoring. Intravenous anesthesia consisted continuous infusion of propofol, ketamine, fentanyl and pancuronium. After anesthesia stabilization animals were randomized: Control group (n=8), HES group (hydroxyethyl starch, n=7) and LR group (lactated Ringer\'s, n=10). Animals of Control Group were anesthetized and observed. Group Animals of group HES and LR were submitted to ANH to reach a pre-established hematocrit around 15%. Blood withdrawal was accomplished simultaneously with plasma expansion performed with hydroxyethyl starch (1:1) or with lactated Ringer\'s (3:1). Pulmonary mechanics and oxygen transport and were measured before blood withdrawal (T0), at the end of hemodilution (T1), and one and two hours after the end of the hemodilution (T2, T3). Lungs biopsies were performed at the end. Data were submitted to analysis of Variance for repeated measures followed by the Tukey test. Results: In regard to all parameters of Control group, there were no significant differences during the whole procedure. The LR group demonstrated a decrease in compliance and an increased in (a-A)DO2 (*P<0,05). Hystopathological lung analysis revealed moderate to serious collapses as well as basement membrane enlargement in group LR. The HES data were similar to that found in control group. Conclusion: These results suggest that in severe ANH, HES preserves pulmonary structure and seems to less interfere with pulmonary mechanics and oxygenation indexes when compared to lactated Ringer\'s
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Roux, Candice Rene. "β-cell response to high fat diet induced metabolic demands in the obese Wistar rat". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6454.
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Thesis (MScMedSc)--University of Stellenbosch, 2011.<br>ENGLISH ABSTRACT: Introduction: A westernized diet rich in saturated fats and sugars, together with a sedentary lifestyle, has contributed to the dramatic increase in obesity during the last decade (Zimmett et al, 2001; Wild et al, 2004). Obesity is associated with dyslipidemia and insulin resistance which are major risk factors for the development of type 2 diabetes (T2D) (Zimmet et al, 2001, Kahn et al, 2006; Schröder et al, 2007). High-fat feeding in rodents induces symptoms similar to the human metabolic syndrome without progression to T2D (Woods et al, 2002; Weir and Bonner-Weir, 2007). The addition of fructose to a high-fat diet exacerbates the insulin resistance and leads to impaired pancreatic function of insulin secretion and glucose intolerance (Basciano et al, 2005; Stanhope et al, 2009).
Aims: The aim of this study was to establish the effect of a high-fat and sucrose/fructose diet on glucose metabolism, the development of insulin resistance and β-cell dynamics.
Methods: Weanling Wistar rats were randomized into two study groups; study one over an experimental period for three months and study two for twelve months. Each study consisted of a control group that received standard rat chow and water; and two experimental groups receiving either a high-fat diet and water (HFD) or a café diet consisting of HFD with the addition of 15% sucrose/fructose (CFD). Fasting glucose and insulin concentrations, intravenous glucose tolerance test (IVGTT), glucose stimulated insulin secretion rates and 2-deoxy-[3H]-D-glucose uptake in muscle, liver and fat were measured. The pancreata were harvested for immunohistochemical labeling of β-cells (insulin), α-cells (glucagon), GLUT2 (glucose transport) and MIB5 (proliferation). Samples of the pancreata were also collected for electron microscopy.
Results and discussion: Feeding Wistar rats a CFD induced obesity, insulin resistance and glucose intolerance. By twelve months the rats had an impaired glucose response with increased IVGTT peak values, area under the curve (AUC) values and glucose clearance rates. Concomitantly, the glucose stimulated insulin secretion rate (GS-ISR) was attenuated. Stimulated glucose disposal as measured by 2-deoxy-[3H]-D-glucose uptake was reduced in muscle and adipose tissue at three months. By twelve months, due to the age of the rats, stimulated glucose uptake declined compared to three months with no difference between groups. After three months the diets had no observable effect on the islets using light microscopy. However, by twelve months morphological changes were observed in both the HFD and CFD groups. In the HFD group large hypertrophied irregular islets with fibrous changes were observed. In the CFD group these morphological changes were more prominent with fibrous segregation and disruption of the normal endocrine arrangement. In addition, the presence of inflammatory cells within the affected islets is consistent with T2D.
Conclusion: High-fat diet fed to Wistar rats induced obesity, abdominal adiposity and insulin resistance. The addition of sucrose/fructose to a high-fat diet exacerbated the insulin resistance and resulted in glucose intolerance and mild hyperglycemia. Morphological changes in the large islets were observed which are consistent with the development of T2D.<br>AFRIKAANSE OPSOMMING: Inleiding: ‘n Verwesterde dieët, ryk aan versadigde vette en suikers tesame met 'n passiewe lewenstyl, het bygedra tot die dramatiese verhoging in vetsug gedurende die laaste dekade (Zimmett et al, 2001; Wild et al, 2004). Vetsug word met dislipidemie en insulienweerstandigheid geassosieer wat hoof risikofaktore is vir die ontwikkeling van tipe 2 diabetes (T2D) (Zimmet et al, 2001; Kahn et al, 2006; Schröder et al, 2007). Hoë-vet voeding in knaagdiere induseer simptome soortgelyk aan menslike metaboliese sindroom sonder die ontwikkeling van T2D (Woods et al, 2002; Weir and Bonner-Weir, 2007). Die byvoeging van fruktose tot 'n hoë-vet dieët vererger insulienweerstandigheid en lei tot verswakte pankreas funksie, insuliensekresie en glukoseintoleransie (Basciano et al, 2005; Stanhope et al, 2009).
Doelwitte: Die doelwitte van die studie was om die effek van hoë-vet en sukrose/fruktose voeding op glukosemetabolisme, die ontwikkeling van insulienweerstandigheid en β-sel dinamika te bepaal.
Metodes: Gespeende Wistar rotte was in twee groepe gerandomiseer; studie een oor ʼn tydperk van drie maande en studie twee oor ʼn tydperk van twaalf maande onderskeidelik. Elke studie het 'n kontrole groep met standaard rot kos en water (control); en twee experimentele diëte wat of ʼn hoë-vet dieët en water (HFD) of 'n kafeedieët groep wat die HFD met die byvoeging van 15% sukrose/fruktose in hul drink water (CFD) ontvang. Fastende glukose en insulien, binneaarse glukose toleransie toets (IVGTT), glukose gestimuleerde insulien sekresie tempo en 2-deoxi-[3H]-D-glukose opname in spier, lewer en vet is gebruik om die effek van die dieët op glukosemetabolisme te bepaal. Die pankreata is uitgehaal vir immunohistochemiese identifisering van β-selle (insulien), α-selle (glukagoon), GLUT2 (glukose transport) en MIB5 (proliferasie). Monsters van die pankreata was ook vir elektronmikroskopie versamel.
Resultate en bespreking: Voeding van ʼn CFD aan Wistar rotte induseer vetsug, insulienweerstandigheid en glukose-intoleransie Teen twaalf maande toon die rotte 'n verswakte respons tot glukose met verhoogde IVGTT piekwaardes, AUC waardes en glukose opruimingswaardes. Terselfdetyd is die glukose gestimuleerde insuliensekresie tempo (GS-ISR) ook verswak. Gestimuleerde glukose opruiming, soos deur 2-deoxi-[3H]-D-glukose opname bepaal, was verlaag in spier en vetweefsel teen drie maande. Teen twaalf maande, weens die ouderdom van die rotte, is die gestimuleerde glukose opname verlaag in vergelyking met drie maande sonder 'n verskil tussen groepe. Na drie maande kon geen sigbare morfologiese verskille met ligmikroskopie tussen die diëte waargeneem word nie. Teen twaalf maande is morfologiese verskille waargeneem in beide die HFD en die CFD groepe. In die HFD groep is groot hipertrofiese onreëlmatige eilande met fibrotiese verandering waargeneem. In die CFD groep was die morfologiese verandering meer gevorder met fibrotiese onderverdeling en ontwrigting van die normale endokriene rangskikking. Die teenwoordigheid van inflammatoriese selle in die geaffekteerde eilande is verenigbaar met T2D.
Afleiding: Die voer van 'n hoë-vet dieët aan Wistar rotte veroorsaak vetsug, abdominale adipositeit en insulienweerstandigheid. Die byvoeging van sukrose/ fruktose tot die hoë-vet dieët vererger die insulienweerstandigheid en veroorsaak glukoseintoleransie en matige hiperglukemie. Morfologiese veranderings in die groter eilande was verenigbaar met T2D.
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Middleton, Danielle Mary Rose Lea. "The prevalence of Salmonella and the spatial distribution of its serovars amongst New Zealand's native lizards : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Zoology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/906.
Full textAbstract:
This thesis considers the prevalence and spatial distribution of Salmonella serovars amongst wild endemic lizards on offshore islands around the coast of New Zealand. The mean test prevalence of faecal excretion of Salmonella was 4.7%. Skinks (Scincidae) were more likely (8.5%) to be carriers of Salmonella than geckos (1.6%). Each island was host to between one and three Salmonella serovars that were not found on any other islands in this study. Two exceptions were Salmonella Bousso and Salmonella Mana which were found on two islands within the same geographical area. Based on the findings of this study, different islands are likely to be hosts to different Salmonella serovars which could have implications for future translocations of native lizards. I also assessed the prevalence and spatial distribution of faecal excretion of Salmonella, Aeromonas and Hafnia alvei within Mana Island. The prevalence of Salmonella on Mana Island was estimated at 5.8%. Salmonella was found predominantly in skinks (10.0%) and less often in geckos (4.1%). H. alvei was found at a prevalence of 1.9%. No Aeromonas species were cultured from any of the cloacal swabs, suggesting that the 95% confidence interval for the true prevalence is 0-3%. Each site sampled in this study was host to one or more unique serovar of Salmonella not found at any of the other sites. The results of this study indicate that Salmonella serovars may become established within populations of lizards and is not spread between them. This may be due to a lack of dispersal of lizards between sites, raising important considerations for the translocation of native lizards. I investigated the prevalence of faecal excretion of Salmonella, H. alvei and Aeromonas by New Zealand native lizards from two captive populations. The mean prevalence of faecal excretion of Salmonella in the captive lizards sampled was 11.5%. There was a higher prevalence of Salmonella within captive population A (22.0%) than in population B (3.6%). No Aeromonas was cultured from any of the lizards. H. alvei was found at a prevalence of 5.2%. The prevalence of Salmonella and H. alvei was significantly higher in captive lizards than in wild populations. Captive lizards may, therefore, not be appropriate founders for new populations of wild lizards. Finally I assessed the different efficiencies of two media and two temperatures in isolating six Salmonella serovars from a reptilian source. All serovars grew equally well at 37°C and 27°C. For most serovars XLD agar was the more successful media than MacConkey agar but the success of different culture media depended on the serovar being cultured. Because lizards are frequently host to a wide range of Salmonella serovars, screening samples using multiple microbiological methods is likely to give the best chance of isolating all Salmonella serovars present.
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Guerra, Flavia Da Ré 1984. "Avaliação morfologica e bioquimica do disco articular da ATM de ratos submetidos a terapia com laser de baixa potencia : estudo experimental em animais portadores de disfuncão temporomandibular." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317511.
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Orientador: Evanisi Teresa Palomari<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biololgia<br>Made available in DSpace on 2018-08-13T18:19:09Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009<br>Resumo: Desordens decorrentes de danos ou doencas relacionadas a ATM afetam o
aparelho mastigador como um todo e sao caracterizadas como desordens
temporomandibulares (DTM). Sabe-se que cerca de sete por cento da populacao
mundial requer tratamento para as DTM. Tecidos cartilaginosos, como os que
constituem o disco articular da ATM, possuem uma capacidade limitada de
regeneracao, e ainda nao existem tecnicas e metodos fidedignos que estimulem o
crescimento de um novo tecido, capaz de auxiliar o tratamento de traumas e doencas
degenerativas. O tratamento com laser de baixa potencia e uma das terapias utilizadas
e, por isto, torna-se imprescindivel o conhecimento de suas acoes sob o ponto de vista
celular e tecidual. Para tal, foram utilizados 24 ratos Lewis machos divididos em quatro
grupos: GC, grupo controle; grupo GD, animais em que foi administrada a toxina
botulinica; grupo GL, animais que receberam o tratamento com o laser de baixa
potencia; grupo GDL, animais em que foi administrada a toxina botulinica e em seguida,
submetidos a terapia com o laser de baixa potencia. Foi realizada analise morfologica
por meio de cortes histologicos corados por HE, AT e picrosirius e; analise bioquimica
por meio de eletroforese em gel SDS-poliacrilamida e dosagem de proteinas. Com base
nos resultados morfologicos e bioquimicos, conclui-se que o modelo de DTM proposto
mostrou-se satisfatorio para estudos desta doenca. Por outro lado, a terapia com o laser
deve submeter seus protocolos clinicos a uma reavaliacao, visto que a mesma
apresentou resultados controversos do ponto de vista tecidual por ter promovido a
sintese de alguns componentes da matriz extracelular e a desestruturacao de outros
essenciais ao bom funcionamento da articulacao envolvida.<br>Abstract: Disorders resulting from injury or disease related to TMJ affect the masticatory
apparatus as a whole and are characterized as temporomandibular joint disorder
(TMJD). It is known that about seven percent of world population requires treatment for
the TMJD. Cartilaginous tissues, such as those that constitute the articular disc of the
ATM, have a limited capacity for regeneration, and yet there are no reliable techniques
and methods that encourage the growth of a new tissue, capable of assisting the
treatment of trauma and degenerative diseases. Treatment with low power laser is one
of the therapies used and, therefore, it is essential knowledge of their actions in terms of
cellular and tissue. To this end, we used 24 male Lewis rats divided into four groups: GC
control group GD animals in that group was given the botulinum toxin; GL group
animals that received treatment with low-power laser; GDL animals in that group was
given the botulinum toxin and then submitted to the low power laser therapy.
Morphological analysis was performed by means of histological sections and stained by
HE, and AT and picrosirius; biochemical analysis by electrophoresis in SDSpolyacrylamide
gel and determination of proteins. It can be concluded based on
morphological and biochemical results, the proposed model of TMD was shown
satisfactory for studies of this disease, while treatment with the laser must submit their
clinical protocols to a revaluation because it showed controversial results of point of
tissue for promoting the synthesis of some components of the extracellular matrix and
destruction of other essential for the proper functioning of the joint involved.<br>Mestrado<br>Anatomia<br>Mestre em Biologia Celular e Estrutural
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Balabuszko, Rachel. "A Study of the Impact of a High Fat and High Cholesterol Diet on Cortical Bone in Captive Baboons." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1514721084433706.
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Monteiro, Rosangela. ""Avaliação das alterações anatômicas cardíacas secundárias ao enfisema pulmonar: estudo experimental em ratos"." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-09082005-111153/.
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Analisamos as alterações cardíacas pós-indução de enfisema por instilação de papaína. Foram avaliados 75 ratos (grupos papaína e controle), sacrificados 30, 60, 90, 120 ou 180 dias pós-instilação. Foram realizados: gasometria do sangue arterial, avaliação morfométrica cardíaca e pulmonar. A papaína produziu destruição alveolar compatível com enfisema, sem repercussão nas trocas gasosas. Ventrículo direito e septo interventricular não apresentaram alterações significativas. Houve redução da área do ventrículo esquerdo, 90 dias pós-indução, e discreto espessamento de sua parede.<br>Cardiac alterations post-induction emphysema by instillation of papain were analyzed. Seventy-five rats (groups papain and control), sacrificed 30, 60, 90, 120 or 180 days post-instillation were evaluated. Arterial blood gases, cardiac and pulmonary morphometrical analysis were performed. Papain administration produced alveolar destruction compatible with emphysema, without arterial blood gases changes. Right ventricle and interventricular septum didn't show alterations. There were left ventricular area decrease (90 days post-induction) and light thickness increase of its wall.
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Martínez, Sagredo Katherinne. "Caracterización morfológica y métrica del hueso periótico del suborden Odontoceti con registro dentro del territorio chileno." Tesis, Universidad de Chile, 2008. http://repositorio.uchile.cl/handle/2250/131051.
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Memoria para optar al Título Profesional de Médico Veterinario<br>Los estudios basados en la comparación de la morfología ósea para la determinación taxonómica han sido ampliamente utilizados, tanto para hacer distinciones a nivel de género como de especie (Becker y Cartajena, 2002), pero el uso del hueso periótico como carácter taxonómico de los Odontoceti, no está aún basado en una sistemática estándar, lo que en términos generales se traduce en un análisis taxonómico a veces subjetivo. Debido a esta compleja forma de “escuchar” que adquieren los Cetáceos al ingresar a un nuevo ambiente marino, cambian además de su anatomía, la forma de captación aérea de sonidos, a una audición adaptada a la recepción y transmisión de sonidos bajo el agua. Los huesos timpánico-periótico, se encuentran casi completamente desconectados del cráneo, unidos sólo mediante ligamentos, es esta pérdida de unión lo que lleva a que estos huesos sean encontrados en su mayoría, aislados de su esqueleto original. Este trabajo intentó por un lado, caracterizar morfológicamente al hueso periótico de especies de Odontoceti registradas en Chile y evaluar por otro, nuevas técnicas de identificación taxonómica basados en la descripción morfométrica del hueso periótico, para conseguir métodos más estandarizados de identificación taxonómica. Este estudio se realizó con 9 restos óseos de perióticos no identificados, 7 de estos pertenecientes a la colección del Museo de Historia Natural (M.N.H.N.) de Santiago, (4 fósiles, 3 actuales), además de 2 huesos perióticos encontrados por particulares que correspondían al mismo animal (KEVa, KEVb). Se trabajó en asociación con el Departamento de Paleontología de mamíferos marinos del M.N.H.N. Para esto se actualizó la lista de especies de Cetáceos registrados en Chile, considerando informes de avistamientos, varamientos, registros de restos óseos actuales y fósiles, mediante revisión bibliográfica. Posteriormente, se recopiló la información morfológica y métrica encontrada, de huesos perióticos por género y especie.
Basado en el método de comparación morfológica, se identificaron los 9 huesos perióticos en sus respectivos géneros. La identificación a nivel de especie no fue posible debido a la similitud morfológica que presenta el hueso periótico dentro de especies del mismo género. La identificación morfométrica, se basó en el análisis de variables (medidas) aplicando el método de componentes principales (ACP). Los resultados del análisis morfométrico muestran que las variables más determinantes en la distribución y agrupamiento de las muestras fueron: A: Largo estándar del periótico, desde la punta del proceso anterior al posterior y del fin del proceso posterior, medido sobre la línea paralela del borde cerebral, B: Grosor del Proceso Superior, a nivel de la apertura timpánica superior, C: Ancho del periótico a través de la porción coclear y el proceso superior, a nivel de la apertura timpánica superior. Estas variables se utilizaron en un nuevo análisis ACP y con estos resultados se realizó un dendrograma. Mediante el método de remuestreo con reemplazo (Bootstrap), se determinó la significancia estadística. De un total de 46 muestras, 16 muestras fueron asociadas correctamente (34.78%), dentro de las cuales sólo una de las muestras desconocidas fue correctamente agrupada con significancia estadística (P < 0.05). Esto muestra una incongruencia en los resultados para la identificación de muestras mediante estos dos métodos, concluyendo, que la morfometría del hueso periótico no entrega datos fiables para una identificación taxonómica.
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Clegg, Margaret. "The comparative anatomy and evolution of the human vocal tract." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271140.
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Chou, Kuang-Yi. "Sodium channel regulatory mechanisms : current fluctuation analysis on frog skin epithelium." Doctoral thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/27148.
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This project examined the role of the cytoskeleton in regulatory mechanisms of the amiloride-sensitive Na⁺ channels in isolated frog skin epithelium. The epithelium from ventral frog skin is a model tissue which has proved significant in our understanding of the basic principles involved in water and Na⁺ homeostasis. In particular, this project examines ways in which local (non-hormonal) and hormonal regulatory mechanisms adjust the Na⁺ permeability of apical membranes of frog skin epithelium. Both mechanisms contain factors that are known to increase the apical membrane Na⁺ permeability mainly by increases in the number of open channels. The origin of these new open channels is unknown but, it is postulated that they could arise either by activation of quiescent channels already present in the apical membrane, or by recruitment of channels from cytoplasmic stores. Regarding the latter hypothesis, we also examined the idea that the cytoskeleton might somehow be involved in the insertion of Na⁺ channels within vesicles, into the apical membrane. This is based on the fact that the cytoskeleton is involved in a similar mechanism whereby, in the toad urinary bladder, anti-diuretic hormone (ADH) causes the insertion of aggregates with water channels. Much current interest focuses on the role of the cytoskeleton in the regulation of epithelial Na⁺ channels. To test this hypothesis, we used noise analysis to examine the effects of disrupting the cytoskeleton, on two different mechanisms which bring about changes in open channel densities. The mechanisms are: (1) lowering mucosal Na⁺ concentration (non-hormonal), and (2) addition of arginine-vasopressin (A VP) (hormonal). Non-hormonal, autoregulatory changes in apical membrane Na⁺ conductance were examined by investigating the effects of reducing the mucosal Na⁺ concentration. Our results showed that lowering the mucosal Na⁺ concentration induced large increases in the open channel density in order to stabilise the transport rate. In addition, we observed an average 55-60% increase in the open channel probability, which implies that in epithelium from Rana fuscigula, changes of channel open probability are also an important mechanism in the autoregulation of channel densities in response to a reduction in mucosal Na⁺. The hormonal control of Na⁺ channels by A VP has been intensively studied by noise analysis and the patch clamp. Our results confirmed previous reports that A VP increases the Na⁺ transport rate by increasing the number of open Na⁺ channels, primarily through large changes in the total number of channels, without a significant change in open probability. Regarding the role of the cytoskeleton in regulation of Na⁺ channels and/or its possible role in control of inserting putative vesicles with Na⁺ channels, we studied the effects of disrupting the cytoskeleton on the two regulatory mechanisms. Disrupting microtubules with colchicine had no, or very little effect on either of the regulatory mechanisms. On the other hand, the integrity of the microfilaments was very important for the autoregulatory changes in the number of open channels. After cytochalasin B treatment, lowering the mucosal Na⁺ concentration did not result in the usual compensatory changes in channel densities. There was no prior evidence that cytochalasin B had any actual effect on the F-actin network in the frog skin epithelium. Accordingly, modified cytochemical techniques were designed to demonstrate and localise F-actin in the epithelial granular cells. The direct immunofluorescent method proved useful, but did not allow sufficient resolution to examine the changes to different populations of actin in the cells. We then modified an immunogold method to suit our conditions, and the results demonstrated the localisation of different pools of F-actin and showed the effects of the cytochalasin B and vasopressin.
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Beaudoin, Sylvie. "Etude du développement séquentiel de la membrane cloacale et de la ceinture pelvienne chez l'embryon de lapin : implications dans l'organogénèse des exstrophies vésicale et cloacale." Paris 5, 2000. http://www.theses.fr/2000PA05CD11.
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L'exstrophie vésicale et ses variantes constituent un ensemble malformatif qui implique des anomalies à la fois viscérales et du bassin osseux, dont le pronostic fonctionnel génito-urinaire reste peu satisfaisant. Les hypothèses jusqu'ici avancées pour en expliquer le développement embryologique ne rendent pas compte de l'anatomie particulière de ses diverses formes cliniques. Le but de ce travail était d'établir la place de l'anomalie osseuse dans la genèse des exstrophies. Le développement normal de la ceinture pelvienne, de la membrane cloacale et de la filière urinaire a donc été étudié chez l'embryon de lapin, en précisant les rapports chronologiques entre les stades d'évolution de ces différentes structures. Dans un deuxième temps nous avons tenté d'induire une exstrophie par lésion élective in vivo de la ceinture pelvienne, chez un embryon de lapin à 12,5 jours de gestation. La formation de la filière vésico-utérale a été trouvée indépendante de la membrane cloacale, mais correlée dans le temps avec la constitution de l'anneau pelvien. De plus, nous avons obtenu un cas d'exstrophie après lésion chirurgicale purement dorsale de l'embryon. Nous proposons donc un nouveau schéma organogénétique de la survenue d'une exstrophie, établi sur ces constatations, et compatible avec la totalité des caractéristiques cliniques de cette malformation.
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McGroarty, James Roy. "Comparative morphology and functional anatomy of the digestive tract of the copepods Tigriopus californicus and Calanus plumchrus : a light and electron microscope study." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24853.
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A study of the digestive tract of the copepods Tigriopus californicus and Calanus plumchrus was carried out using techniques of light and electron microscopy. In Tigriopus californicus, the foregut contains a curved cuticle lined esophagus which extends from the ventral mouth to the junction of the anterior midgut and midgut caecum. The noncuticulized portion of the digestive tract consists of: 1. A single spherical midgut caecum located anteriorly, 2. An anterior midgut, 3. A posterior midgut. There are cuticulized anterior and posterior hindgut regions ending in a dorsal anus.
In Calanus plumchrus, the foregut consists of a cuticle lined esophagus extending from the ventral mouth to the junction of the midgut and the midgut diverticulum. The noncuticulized portion of the digestive tract consists of: 1. A single midgut diverticulum, 2. A midgut that is divisible on the basis of epithelial cell type and function. There is a long abruptly narrowing cuticle lined hindgut ending in an anus.
In Tigriopus californicus, four cell types could be distinguished and from such ultrastructural characteristics as the position in the digestive tract, abundance, position, and type of organelles, lipid content, presence and type of vesiculation, and electron density, functions for the cells were determined. Cell type '1' is an embryonic 'stem' cell. It functions as a replacement cell and differentiates
when cells are worn away or lost in secretion. Cell type '2' is mainly a secretory cell and functions in the synthesis of proteins. It also plays a role in lipid absorption. Cell type '3' is absorptive, mainly for lipids. Cell type M1, found only in the anterior midgut is also an absorptive cell. The presence of electron dense vesicles suggests that lipid absorption is not its major function.
From the abundance of cell type and from examination of the ultrastructure in the various regions of the digestive tract, the following conclusions were made: 1. The midgut caecum functions in the absorption of digested nutrients. 2. The anterior midgut plays a role in nutrient absorption but is important in secretion. 3. The posterior midgut cells are mainly absorptive.
In Calanus plumchrus, five cell types could be distinguished.
Cell type 'E' is an undifferentiated 'stem1 cell. Cell type 'R' found in the midgut diverticulum and posterior midgut regions, is absorptive. Its developed basal surfaces suggest a transport function between the cell and the haemo-coel . Cell type 'D' is found in the glandular region of the midgut and is absorptive. It has an ultrastructure similar to that observed for cell type 'R'. Cell type 'B' is a large vacuolated absorptive cell found in the glandular region of the midgut. Cell type 'F' functions in the synthesis and secretion of digestive enzymes.
In Calanus plumchrus, the midgut diverticulum is specialized for the absorption of digested nutrients and transport of metabolites to the haemocoel . The anterior midgut regions are mainly absorptive. It includes a vacuolated glandular region specialized for pinocytotic absorption. In the middle section of the midgut, adjacent and posterior to the glandular region, is an area of epithelial cells specialized for secretion. The posterior midgut regions are mainly absorptive.
In Tigriopus californicus biological markers can be used to determine cell type function in correlation with the observed ultrastructure.<br>Science, Faculty of<br>Zoology, Department of<br>Graduate
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Shaw, Kate. "An analysis of morphological variation within and between stream populations of Gasterosteus aculeatus Linnaeus." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24918.
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Two small streams on Vancouver Island, British Columbia, were examined
for patterns of morphological variation in Gasterosteus aculeatus. A progressive analysis beginning with Principle Components Analysis, followed by Nested and Partially Nested Multiple Analysis of Variance and then Duncan's Multiple Range Test was used for pattern determination. This new technique allows the researcher to sequentially isolate the pattern of variation at different levels of generality from species to individual organisms. The pattern of variation for G. aculeatus in Bonsall Creek and Nunns Creek can be summarized as follows: The largest amount of variation accounted for by the analysis is interpreted
as individual variation. Populations also account for a large amount of variation and show consistent, fully nested patterns of variation
at each of the analysed geographic and microgeographic levels. These populations are probably genealogical units. The so-called "leiurus" and "trachurus" forms on the Pacific coast of North America do not appear to be evolutionary entities, but to be historical artifacts
that are best viewed as labels for the extremes of a continuum of variation. In areas where distinct populations meet, different clines are documented in the two stream systems. In Nunns Creek there is a smooth cline between populations, whereas in Bonsall Creek there is a step cline.<br>Science, Faculty of<br>Zoology, Department of<br>Graduate
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Powlik, James. "Feeding structures of the white shark, Carcharodon Carcharias (Linnaeus), with notes on other species." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29758.
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Fresh and prepared museum specimens of the white shark Carcharodon carcharias, bull shark Carcharhinus leucas, and salmon shark Lamna ditropis were measured and compared with respect to tooth position and anterior buccal cavity dimensions. Coordinates of functional tooth position were defined by 1) deviation from the midline and 2) degree of erection. Tooth positions were not unique in any region of the mouth/ but demonstrated less variablity within 30° of the midline, particularly for male specimens of all three species (71.48° +- 10° erect) and all Carcharhinus leucas specimens (46.58° +-.96° erect).
Analysis of high-speed videotape of white shark feeding indicated a 15.7° reduction in tooth cutting angle with jaw adduction following upper jaw protraction. It is suggested that such changes in tooth cutting angles during feeding are principally the result of jaw flexure, and may make the teeth more effective by angling them inward towards the gullet.
Values for tooth removal from fresh-frozen white shark material using a tensile testing apparatus ranged from 12 kg (for a 110° erect tooth) to 70 kg (for a 59° erect tooth). Removal load was applied directly outward from the mouth to simulate a resistant prey item, and was not significantly different for degree of erection or tooth position on the jaw margin. Tooth position is seen to change with jaw protraction, however this change does not enhance tooth functionality by increasing the load required to remove the tooth.<br>Science, Faculty of<br>Zoology, Department of<br>Graduate
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Lin, Charles. "Spinal Cord Injury: Exploring the Histology of Electrospun Implants In Vivo." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2167.
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Spinal cord injury results in loss of motor function and sensory perception. A myriad of obstacles prevent axonal regeneration and ultimately functional recovery in those afflicted with spinal cord injury. Combinatorial strategies addressing many of these obstacles simultaneously have shown promising results. Laboratories investigating contusional spinal cord injuries must overcome the formation of a fluid filled cyst, a physical gap that axons must traverse, at the injury epicenter. To fill the cyst, our lab has generated a 3-D electrospun matrix that is capable of directing neurite outgrowth, delivering neurotrophic support, and reducing the activity of neuroinhibitory compounds. These electrospun matrices were surgically implanted into female Long Evans Hooded rats aged approximately 60 days using a complete transection model of SCI. Following injury, rats with implants showed greater functional recovery than controls. In Chapter 1, we introduce spinal cord injury, the epidemiology, pathology and potential for regeneration, followed by our novel electrospun implant. Chapter 2 details the materials and methods. In Chapter 3, we relate the functional recovery seen to a histological analysis. The histological analysis consists of three parts: the implant integration into the host, the axons above, in and below the implant, and the functional vascular supply found within the implant. In Chapter 4, we designed a modified implant and discuss the use of this implant in vivo. With our modified implant we were able to demonstrate cellular influx and the generation of a vascular network within the implant, but poor axonal regeneration. Finally in chapter 5, I discuss potential future modifications to our electrospun matrix as well as suggestions to consider for improved functional outcome.
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Mazyala, Eric John. "A morphological study of the dermal fibroblast." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/4079.
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Xynos, Ioannis D. "Bioactive glasses for the in vitro synthesis of bone tissue." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/11494.
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Elebute, Modupe Olaitan. "Evaluation of haemopoiesis in de-novo haemolytic paroxysmal nocturnal haemoglobinuria." Thesis, St George's, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271169.
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Munro, James McKenzie. "Pathogen-host relationships between Erysiphe cruciferarum and members of the family Cruciferae." Thesis, University of Edinburgh, 1985. http://hdl.handle.net/1842/27079.
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Gonzalez, Vargas Diego. "Supplementation of cereal straws with lucerne and sugar beet pulp in diets for ruminants." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/28124.
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Watson, Patricia A. "The biochemistry and physiology of the immature cereal pericarp." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/27625.
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Smith, Rosalind Anita Jane. "Patch-clamp studies of macroscopic and single-channel currents in mouse neuroblastoma cells." Thesis, University of Leicester, 1988. http://hdl.handle.net/2381/33613.
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Cells from the clonal cell line N1E115, a mouse tumour of sympathetic origin, differentiate both morphologically and electrophysiologically when cultured in medium containing dimethylsulphoxide. This technique was used to obtain cells for electrophysiological recording. Macroscopic currents were measured using the whole-cell patch-clamp technique and two currents, one thought to be carried mainly by sodium ions and one mainly by potassium ions, were identified. The kinetics of the potassium current, which are voltage dependent, suggested that this was a delayed rectifier. A single-channel current which was selective for potassium ions was recorded using the cell-attached patch-clamp recording technique. The channel was thought to be the unitary current correlate of the macroscopic potassium current on the basis of its activation kinetics. The channel was shown to have two open states of different conductance, one having approximately two-thirds the conductance of the other. The single-channel kinetics were measured and it was shown that the open time distribution of the channel, the latency to its first opening after a voltage step and the relative times spent in each of the two open states are voltage dependent. The amplitude of these currents was reduced by application of tetraethylammonium ions to the extracellular face of the membrane patch and the concentration- and voltage-dependence of this block were investigated. Two further unitary currents were identified using the excised patch-clamp recording technique: a calcium-activated non-selective cation current and a calcium-activated potassium current. The conductance and voltage-dependence of both currents were investigated.
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Lambton, P. A. "The photo-inhibition of seed germination and the induction of secondary dormancy." Thesis, University of Leicester, 1985. http://hdl.handle.net/2381/35323.
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A study of photoinhibition of seed germination and the induction of secondary dormancy has been made on weedy species that tend to produce large numbers of small, light-sensitive seeds. Both light-requiring (e.g., Chenopodium album) and light-inhibited (e.g., Amaranthus caudatus) species were used but nevertheless were found to show similar responses to high fluence irradiation, differences being largely ones of varying sensitivity. All species tested (except Digitalis purpurea) showed a marked inhibition of germination in continuous fluorescent white light supplemented with far-red compared to the response to fluorescent white light only. Urtica urens and A. caudatus germination, however, could be inhibited by fluorescent white light only and this response was dependent on both time and fluence rate. Interestingly, A. caudatus is a dark germinator whereas U. urens is light requiring (i.e., a small amount of light promotes germination but a large amount is inhibitory). The inhibitory action of prolonged light is dependent on photon fluence rate. In photoinhibition mediated through phytochrome cycling rate of the pigment appears to be important. However, cycling rate per se cannot explain all the observed responses; and the interuption of dark processes is another important factor. Cycling rate effects are increased when photoequilibrium is low. There is also a blue light photoreceptor of unknown form which shows fluence dependent characteristics in its photoinhibitory activity. Secondary dormancy is induced in seeds which have the ability to germinate but are prevented from doing so. In respect to the light environment, the same light conditions which inhibit germination also tend to induce secondary dormancy although there is no direct evidence on the action of blue light operating through the blue photoreceptor. The depth of secondary dormancy increases with the time of incubation in the inhibitory conditions and also is deeper for low photoequilibrium and high photon fluence rate. High photon fluence rate fluorescent white light inhibits the germination of U. urens but the high photoequilibrium established allows the seed to germinate in subsequent darkness. Photoinhibition of germination and induction of secondary dormancy have adaptive advantages for survival of the species since seedlings can avoid the competitive stresses of a stand of vegetation and the desiccating environment of the soil surface in full sunlight. Photoinhibition appears to act by preventing the active processes of germination from occurring, which thus enables the seeds to pass through cycles of hydration and dehydration without being damaged.
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Ward, Thomas Anthony. "Voltage and patch clamp studies of the ionic currents in snail neurones and frog skeletal muscle." Thesis, University of Leicester, 1985. http://hdl.handle.net/2381/33620.
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The inactivation of the calcium permeability in Helix aspersa neurones was studied in relation to [Ca]. Injection of calcium ions was shown to reduce the voltage activated calcium current by increasing [Ca]. This was proved to be by a process of inactivation of the calcium current, rather than a direct effect of increased [Ca] on the driving force for calcium across the membrane. [Ca] was measured using ion sensitive electrodes, and a mean resting level of 2.66+/-0.65 x 10-7K was obtained. The inactivation of the calcium current was found to fit 1 to 1 binding between calcium and the receptor responsible for inactivation giving a Kd, of 4.8 x 10-7K. A number of techniques were used to influence the intracellular cAMP concentrations of the snail neurones in an attempt to isolate some form of metabolic control of the calcium permeability. However, no consistent responses could be obtained. The patch clamp technique was used to look at the unitary current in frog skeletal muscle. Membrane vesicles formed from the sarcolemma by enzyme treatment, were found to reduce the number of problems associated with the use of the technique on intact muscle fibres. Sodium and delayed rectifier potassium channels were identified in the vesicles, having conductances in the range 12-15pS and l6-24pS, for the two types of current. The kinetics of the sodium channels in the vesicles were found to be slightly slower than those reported for the intact frog skeletal muscle. Kowever, they could still be fitted to the m h model of Odgkin and Luxley. Studies of the kinetics of the delayed rectifier potassium channels suggested a model for the channel different from the four-closed state system proposed by odgkin and luxley. Finally, experiments were performed on snail neurons in order to observe the unitary calcium activated potassium currents.
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Loudon, Mary. "Arterial wall renin-like activity and blood pressure regulation in the rat." Thesis, University of Leicester, 1985. http://hdl.handle.net/2381/34141.
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In this study the Importance of the generation of angiotensin II within the blood vessel wall in determining the pressor response to injected renin was investigated. An injection of renin, given to rats after bilateral nephrectomy, produced a pressor response. The level of circulating renin, although initially elevated, returned to the normal range within three hours. However, the level of renin present in the aortic wall remained significantly elevated for six hours after the injection, as did the pressor response. Infusions of the angiotensin II antagonist saralasin at three and six hours after the renin injection confirmed that the pressor response was maintained by the renin-angiotensin system. An injection of renin into normal rats produced the same initial pressor response as was observed in the nephrectomised rats. However, the blood pressure subsequently returned to the pre-injection level after one hour. In the normal rats the pressor response was not related to the level of renin present within the aortic wall. It was concluded that the activity of the renin present within the blood vessel wall was more relevant to the control of blood pressure than the circulating level. However, when the kidneys were present this local action of the renin-angiotensin system was overriden by renal anti-hypertensive systems. This was not dependent on the presence of the renal medulla since the pressor response after chemical renal medullectomy was the same as that observed in the normal rats. The increase in the level of renin within the aortic wall after the injection of exogenous renin confirmed that renin can enter the walls of blood vessels from the circulation. It was concluded that this occurred by a process of passive diffusion.
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Johnson, M. H. "An analysis of the neural systems underlying filial preference behaviour in the domestic chick." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356655.
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Bekkers, J. M. "Studies of single ion channels : Nonstationary sodium current fluctuations in squid axon, and patch clamp analysis of acetylcholine-activated channels in cultured rat skeletal muscle." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372643.
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Bradley, A. "Isolation characterization and developmental potential of murine embryo-derived stem cells." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373263.
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Goddard, R. J. "Diurnal regulation of ovulation and implantation in mammals." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373665.
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Williams, P. H. "On the distribution of bumble bees : with particular regard to patterns within the British Isles." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355051.
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Newsholme, D. M. "Studies of selection in vitro for resistance to Leptosphaeria maculans (Desm.) Ces. and de Not. (stem canker) : Using secondarily embryonic cultures of Brassica napus L. ssp. oleifera (Metzg.) Sinsk (winter oilseed rape)." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372279.
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Duffen, J. "Dietry control of the salmonella carrier state in poultry." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355506.
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Matthews, H. R. "Electrophysiological studies of vertebrate rod photoreceptors." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373259.
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Saphier, D. J. "Electrophysiology and endocrine function of rat tuberoinfundibular neurones." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373694.
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Zhang, J. "A role for abscisic acid in root to shoot communication of changes in the soil environment." Thesis, Lancaster University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234647.
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Wyness, L. E. "Effects of water stress on the infectivity and nutrition of Erysiphe pisi, powdery mildew of pea." Thesis, Lancaster University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356335.
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Silva, D. L. R. de. "A critical assessment of the role of abscisic acid and calcium ions in regulating stomatal movements in Commelina communis L." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373807.
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Wolfenden, J. "Nitrogen fixation associated with Spartina anglica : A study of nitrogen-fixing microorganisms and their contribution to the growth of a developing Spartina anglica marsh in the Lune Estuary." Thesis, Lancaster University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355042.
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Rowland, A. J. "Fluxes of nitrogen and carbon in barley exposed to NO2̲." Thesis, Lancaster University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375193.
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Battram, J. C. "Chloride balance in the brown trout Salmo trutta L. in neutral and acidified waters." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373479.
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Wright, E. A. "The effects of sulphur dioxide and nitrogen dioxide, singly and in mixture, on the growth of birch trees." Thesis, Lancaster University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372938.
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Afzal, Faiza. "The role of nitric oxide in the control of osteoblast metabolism and maintenance of bone integrity." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271576.
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Stevenson, Shirley Anne. "The plasma membrane cytoskeleton of the cardiac muscle cell : spatial organisation and interactions of component proteins." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300484.
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