After drinking water, the fluid quickly leaves the stomach thereby creating a hypotonic luminal environment in the duodenum. This in turn constitutes a potential threat to the integrity of the duodenal epithelium. It therefore seems highly likely that luminal hypotonicity activates physiological mechanisms that aim to increase luminal osmolality. One such physiological mechanism may be to increase mucosal permeability thereby facilitating the transport of osmolytes into the lumen. A draw-back of performing experiments in anesthetized animals is that surgery per se depresses gut functions, such as peristalsis, by mechanisms involving endogenous prostaglandins. In this thesis it is shown that inhibition of cyclooxygenase-2 (COX-2), in animals subjected to an abdominal operation, restore and/or improve duodenal functions such as motility, mucosal bicarbonate secretion, hypotonicity-induced increase in mucosal permeability and the osmolality-adjusting capability. Experiments revealed that the stomach is resistant to hypotonic challenge while the jejunum is more sensitive to hypotonicity-induced increase in mucosal permeability than the duodenum. The hypotonicity-induced increase in duodenal mucosal permeability is not due to injury but possibly reflects physiological dilatation of paracellular shunts. Luminal perfusion of the duodenum with an isotonic solution lacking Cl- decreased bicarbonate secretion while the lack of luminal Na+ increased mucosal permeability. Stimulation of bicarbonate secretion by COX-2 inhibition is to a large extent dependent on luminal Cl- while that induced by vasoactive intestinal peptide is not. The hypotonicity-induced increase in mucosal permeability involves the release and action of serotonin (5-HT) on 5-HT3 and 5-HT4 receptors and stimulation of enteric nerves strongly implicating physiological regulation of this process.

The purpose of this research project was to develop and characterise matrix type microspheres prepared from Eudragit® L100, containing insulin as model peptide drug as well as an absorption enhancer, N-trimethyl chitosan chloride (TMC), to improve intestinal absorption via the paracellular route. Insulin loaded microspheres were prepared using a single water in oil emulsification/evaporation method in accordance with a fractional factorial design (23) and subsequently characterised in terms of morphology as well as internal structure. Also, insulin and TMC loading were determined using a high pressure liquid chromatography analysis (HPLC) and colorimetric assay, respectively. Scanning electron microscopic characterisation revealed that most microsphere formulations showed a spherical shape and smooth surface with a sponge-like internal structure as well as relatively good homogeneity in terms of size distribution. Insulin loading ranged from 27.9 ± 14.25 – 52.4 ± 2.72% between the different formulations. TMC loading was lower than for insulin and ranged from 29.1 ± 3.3 - 37.7 ± 2.3% between the different formulations. The pronounced difference in insulin and TMC loading between the microsphere formulations is probably the result of the multitude parameters involved as well as the complex physicochemical processes which govern emulsification/solvent evaporation. Based on the microsphere characterisation results, two formulations were selected (i.e. B and F) for further characterisation (i.e. particle size distribution, dissolution behaviour, and enteric nature) and for in vitro evaluation of insulin transport across excised Fischer (FSR) rat intestinal tissue using a Sweetana-Grass diffusion chamber. Particle size analysis by means of laser light diffraction of the two selected microsphere formulations revealed that the mean particle size (based on volume) ranged from 135.7 ± 41.05 to 157.3 ± 31.74 m. Dissolution results for microsphere Formulations B and F revealed that both insulin and TMC were released from the microsphere formulations in an alkaline environment (pH 7.4). The mean dissolution time (MDT) for insulin ranged from 34.5 ± 4.01 to 42.6 ± 9.06 min, while the MDT for TMC ranged from 1.2 ± 1.73 to 6.8 ± 6.42 min. Statistical analysis revealed no significant differences in the MDT of either insulin or TMC (p-value > 0.05) between the two formulations, although the difference between insulin and TMC of each formulation was significant (p-value < 0.05). Microsphere formulations B and F released 36.92 and 48.21% of their total drug content over a period of 1 h in 0.1 M HCl. Microsphere Formulation B showed 8.3 ± 0.52% and formulation F 8.9 ± 2.26% transport of the initial insulin dose after a period of 120 min across excised rat intestinal tissue. The increase in insulin transport by the microsphere formulations compared to that of the control group (i.e. insulin alone) correlated well with the decrease in transepithelial electrical resistance (TEER) caused by the microsphere formulations. The transport of insulin from Formulations B and F represented transport enhancement ratios of 10.67 and 9.68, respectively. Insulin loaded EudragitL100 microspheres containing TMC were successfully prepared by emulsification/solvent evaporation that demonstrated promising potential to serve as oral drug delivery systems for insulin. The microspheres exhibited improved insulin permeability across intestinal epithelial tissue; however, its enteric properties should be improved and clinical effectiveness need to be confirmed by future in vivo studies. / Thesis (MSc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2013.

The purpose of this research project was to develop and characterise matrix type microspheres prepared from Eudragit® L100, containing insulin as model peptide drug as well as an absorption enhancer, N-trimethyl chitosan chloride (TMC), to improve intestinal absorption via the paracellular route. Insulin loaded microspheres were prepared using a single water in oil emulsification/evaporation method in accordance with a fractional factorial design (23) and subsequently characterised in terms of morphology as well as internal structure. Also, insulin and TMC loading were determined using a high pressure liquid chromatography analysis (HPLC) and colorimetric assay, respectively. Scanning electron microscopic characterisation revealed that most microsphere formulations showed a spherical shape and smooth surface with a sponge-like internal structure as well as relatively good homogeneity in terms of size distribution. Insulin loading ranged from 27.9 ± 14.25 – 52.4 ± 2.72% between the different formulations. TMC loading was lower than for insulin and ranged from 29.1 ± 3.3 - 37.7 ± 2.3% between the different formulations. The pronounced difference in insulin and TMC loading between the microsphere formulations is probably the result of the multitude parameters involved as well as the complex physicochemical processes which govern emulsification/solvent evaporation. Based on the microsphere characterisation results, two formulations were selected (i.e. B and F) for further characterisation (i.e. particle size distribution, dissolution behaviour, and enteric nature) and for in vitro evaluation of insulin transport across excised Fischer (FSR) rat intestinal tissue using a Sweetana-Grass diffusion chamber. Particle size analysis by means of laser light diffraction of the two selected microsphere formulations revealed that the mean particle size (based on volume) ranged from 135.7 ± 41.05 to 157.3 ± 31.74 m. Dissolution results for microsphere Formulations B and F revealed that both insulin and TMC were released from the microsphere formulations in an alkaline environment (pH 7.4). The mean dissolution time (MDT) for insulin ranged from 34.5 ± 4.01 to 42.6 ± 9.06 min, while the MDT for TMC ranged from 1.2 ± 1.73 to 6.8 ± 6.42 min. Statistical analysis revealed no significant differences in the MDT of either insulin or TMC (p-value > 0.05) between the two formulations, although the difference between insulin and TMC of each formulation was significant (p-value < 0.05). Microsphere formulations B and F released 36.92 and 48.21% of their total drug content over a period of 1 h in 0.1 M HCl. Microsphere Formulation B showed 8.3 ± 0.52% and formulation F 8.9 ± 2.26% transport of the initial insulin dose after a period of 120 min across excised rat intestinal tissue. The increase in insulin transport by the microsphere formulations compared to that of the control group (i.e. insulin alone) correlated well with the decrease in transepithelial electrical resistance (TEER) caused by the microsphere formulations. The transport of insulin from Formulations B and F represented transport enhancement ratios of 10.67 and 9.68, respectively. Insulin loaded EudragitL100 microspheres containing TMC were successfully prepared by emulsification/solvent evaporation that demonstrated promising potential to serve as oral drug delivery systems for insulin. The microspheres exhibited improved insulin permeability across intestinal epithelial tissue; however, its enteric properties should be improved and clinical effectiveness need to be confirmed by future in vivo studies. / Thesis (MSc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2013.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Made available in DSpace on 2014-06-11T19:31:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-27Bitstream added on 2014-06-13T18:41:44Z : No. of bitstreams: 1 uribediaz_ap_dr_jabo.pdf: 327728 bytes, checksum: 95978c4b4ea30b83afc2bcabbfd833d4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Trabalhos recentes relatam a eficácia do azul de metileno na prevenção dos danos impostos por espécies reativas de oxigênio aos tecidos de vários órgãos, em vários modelos de isquemia/reperfusão. Este estudo foi concebido com o fito de avaliar o efeito do azul de metileno sobre as respostas clínico-laboratoriais, na obstrução experimental do jejuno em equinos, associada à exposição de lipopolissacarídeo. Dois grupos de animais foram submetidos à indução da endotoxemia e à obstrução experimental do jejuno em período anterior. Posteriormente administrou-se em um deles, infusão de azul de metileno (3 mg/kg I.V), 15 minutos antes da obstrução experimental, e no outro, a mesma infusão 15 minutos antes da desobstrução do jejuno. Foi realizada avaliação clínica, hematológica e bioquímico-sérica, e perfil bioquímico e citológico do líquido peritoneal a partir de aferições em oito tempos durante 12 horas, também foram caracterizadas as lesões intestinais. Após 3 horas de isquemia, verificou-se hemorragia, edema, infiltração de neutrófilos e desprendimento da mucosa. Essas lesões manifestaram-se predominantemente após a reperfusão, e de forma concomitante com o aumento dos componentes celulares e moleculares da inflamação, tanto no sangue quanto no líquido peritoneal. Contudo, todos os achados foram discretamente menos evidentes nos animais que receberam o azul de metileno antes da fase de reperfusão. Não é possível afirmar efeito benéfico do azul de metileno sobre a resposta dos equinos na obstrução experimental do jejuno. / Intestinal ischemia is one of the most serious intra-abdominal alterations and reflects extremely elevated morbility and mortality. Reoxygenation on the ischemic tissue produces deleterious inflammatory events with consequences even more severe than the ischemia itself. Methylene blue, due to this action as an inhibitor of free-radical formation. The objective of this test was to study the effects of methylene blue on the clinical and laboratory response before and after the experimental obstruction of the jejunum, associated to the exposition of lypopolysacharide. Two groups of animals were submitted to endotoxemia and experimental obstruction of the jejunum. After, in one group was administered, intravenously, a solution of methylene blue (3 mg/kg), immediately before the experimental obstruction, in the other group, the solution was administered immediately before interrupt the obstructive process in the intestinal segment. The horses were submitted to the evaluation of clinical signs and laboratory response during the 12 hours of study. Based on the clinical and laboratory findings we concluded that, the administration of methylene blue was not able to avoid the clinical and laboratory responses in the experimental model proposed for this study.

Made available in DSpace on 2014-06-11T19:28:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-18Bitstream added on 2014-06-13T19:36:51Z : No. of bitstreams: 1 borges_ll_me_jabo.pdf: 1223418 bytes, checksum: 842f71b580aef2f2202cf5ed68a06a43 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Foi realizado um experimento com frangos de corte machos e fêmeas, com duração de 43 dias, no Aviário Experimental do Departamento de Zootecnia da Faculdade de Ciências Agrárias e Veterinárias, UNESP, Campus de Jaboticabal, SP. O objetivo foi o de avaliar a eficácia de três programas de alimentação contendo virginiamicina, sobre o desempenho, rendimento de carcaça e morfometria intestinal de frangos de corte machos e fêmeas, criados sobre cama reutilizada. Foram utilizados 2.160 pintos de um dia de idade da linhagem Cobb, distribuídos em 72 boxes com 30 aves cada. O delineamento experimental adotado foi em blocos com esquema fatorial 3x2 (três programas alimentares e dois sexos), com doze repetições de 30 aves cada. As dietas experimentais consistiram em: T1 (dieta inicial, crescimento e final, isentas de virginiamicina), T2 (adição de virginiamicina nas dietas inicial, crescimento e final) e T3 (adição de virginiamicina nas dietas inicial e crescimento). Aos 21, 35 e 42 dias de idade foram avaliados os dados de desempenho (peso médio, ganho de peso, consumo de ração, conversão alimentar e viabilidade criatória) e aos 42 dias de idade as características de carcaça (rendimento de carcaça, peito, peito desossado, coxa + sobrecoxa e asas). Aos 43 dias de idade, amostras de duodeno e jejuno foram retiradas para análise de morfometria de altura e largura das vilosidades, profundidade de cripta e relação a altura de vilosidade/profundidade de cripta, no Laboratório de Histologia e Embriologia do Departamento de Morfologia e Fisiologia Animal da FCAV, UNESP. Os tratamentos T2 e T3 proporcionaram melhores resultados para peso, ganho de peso e conversão alimentar, no entanto, não interferiram no consumo de ração, viabilidade criatória e no rendimento de carcaça e cortes quando comparados com o tratamento T1. A utilização de virginiamicina proporcionou melhor... / An experiment was conducted with broiler males and females, with duration of 43 days in the Experimental Aviary of the Animal Science Department at Agriculture and Veterinary Sciences Faculty, UNESP, Jaboticabal, SP. The objective was to evaluate the efficacy of three feed programs containing virginiamycin on performance, carcass and intestinal morphology of broiler males and females reared on reused litter. We used 2,160 chicks a day old, Cobb, distributed in 72 boxes with 30 birds each. The experiment was arranged in blocks with a 3x2 factorial arrangement (three food programs and two sexes), with twelve replicates of 30 birds each. The experimental diets consisted of T1 (starter, growth and final diet free virginiamycin), T2 (addition of virginiamycin in diets starting, growing and finishing) and T3 (addition of virginiamycin in diets and initial growth). At 21, 35 and 42 days of age were evaluated performance data (average weight, weight gain, feed intake, feed conversion and livability) and at 42 days old carcass characteristics (carcass yield, breast, boneless breast, thigh + drumstick and wings). At 43 days of age, samples of duodenum and jejunum were removed for morphometric analysis of villus height and width, crypt depth and compared villus height/crypt depth in the Histology and Embryology Laboratory, of Morphology and Physiology Departament, from FCAV, UNESP. The treatments T2 and T3 provided better results for weight, weight gain and feed conversion, however, did not affect feed intake, livability and carcass yield and cuts when compared with T1. The use of virginiamycin provided better development of the villi and crypts, when compared with treatment without antibiotic in the study

Orientador: Áureo Evangelista Santana / Banca: Raquel Yvonne Arantes Baccarin / Banca: Rafael Resende Faleiros / Banca: Marcia Rita Fernandes Machado / Banca: Juliana Regina Peiró / Resumo: Trabalhos recentes relatam a eficácia do azul de metileno na prevenção dos danos impostos por espécies reativas de oxigênio aos tecidos de vários órgãos, em vários modelos de isquemia/reperfusão. Este estudo foi concebido com o fito de avaliar o efeito do azul de metileno sobre as respostas clínico-laboratoriais, na obstrução experimental do jejuno em equinos, associada à exposição de lipopolissacarídeo. Dois grupos de animais foram submetidos à indução da endotoxemia e à obstrução experimental do jejuno em período anterior. Posteriormente administrou-se em um deles, infusão de azul de metileno (3 mg/kg I.V), 15 minutos antes da obstrução experimental, e no outro, a mesma infusão 15 minutos antes da desobstrução do jejuno. Foi realizada avaliação clínica, hematológica e bioquímico-sérica, e perfil bioquímico e citológico do líquido peritoneal a partir de aferições em oito tempos durante 12 horas, também foram caracterizadas as lesões intestinais. Após 3 horas de isquemia, verificou-se hemorragia, edema, infiltração de neutrófilos e desprendimento da mucosa. Essas lesões manifestaram-se predominantemente após a reperfusão, e de forma concomitante com o aumento dos componentes celulares e moleculares da inflamação, tanto no sangue quanto no líquido peritoneal. Contudo, todos os achados foram discretamente menos evidentes nos animais que receberam o azul de metileno antes da fase de reperfusão. Não é possível afirmar efeito benéfico do azul de metileno sobre a resposta dos equinos na obstrução experimental do jejuno. / Abstract: Intestinal ischemia is one of the most serious intra-abdominal alterations and reflects extremely elevated morbility and mortality. Reoxygenation on the ischemic tissue produces deleterious inflammatory events with consequences even more severe than the ischemia itself. Methylene blue, due to this action as an inhibitor of free-radical formation. The objective of this test was to study the effects of methylene blue on the clinical and laboratory response before and after the experimental obstruction of the jejunum, associated to the exposition of lypopolysacharide. Two groups of animals were submitted to endotoxemia and experimental obstruction of the jejunum. After, in one group was administered, intravenously, a solution of methylene blue (3 mg/kg), immediately before the experimental obstruction, in the other group, the solution was administered immediately before interrupt the obstructive process in the intestinal segment. The horses were submitted to the evaluation of clinical signs and laboratory response during the 12 hours of study. Based on the clinical and laboratory findings we concluded that, the administration of methylene blue was not able to avoid the clinical and laboratory responses in the experimental model proposed for this study. / Doutor

Para evitar a presença de microorganismos nas rações fornecidas para animais de laboratório, são utilizados processos de esterilização como a autoclavagem, porém esta ocasiona perda de nutrientes, como as proteínas, devido à alta temperatura usada. A deficiência protéica pode afetar a atividade celular, provocando diferentes alterações nos tecidos. Por estes fatos, objetivou-se avaliar a ação da ração autoclavada sobre os neurônios do plexo mioentérico do jejuno de ratos em período de crescimento. Para tanto, foram utilizados ratos em período dedesmame (21 dias) provindos de mães que receberam ração autoclavada ou não autoclavadadurante a gestação e lactação e ratos em período de pós-desmame (21 a 70 dias) alimentados com o mesmo tipo de dieta que as mães recebiam. Para a mensuração do perfil do corpo celular e contagem do número de neurônios por área, estes foram evidenciados pelo método de nadh-diaforase. O peso corpóreo dos animais não apresentou diferença significativa em relação ao tipo de alimentação (p > 0,05). Houve uma diminuição do comprimento jejuno-íleo em ratos alimentados com ração autoclavada (p > 0,05). O número de neurônios por área aumentou aproximadamente 10% para ratos que receberam ração autoclavada (p > 0,05). Já a área do perfil dos corpos dos neurônios apresentou um aumento para ratos alimentados com ração autoclavada, sendo este significativo para animais em período de desmame. Todos os fatores observados apresentaram diferença significativa em relação às idades / Autoclaving is the most common sterilization process to avoid the presence of pathogens in the diet of laboratory animals. However, it may cause the loss of nutrients such as proteins due to the high temperature used. The protein deficiency can affect cellular activity, leading todifferent changes in the tissues. Due to these facts, this research aimed to verify the effect of autoclaved diet in the jejunum neurons of the myenteric plexus in rats during their growing phase. The experiment groups were constituted by rats in weaning period (21 days) from mothers that received autoclaved or not diets during the gestation and lactation, and rats in post weaning period (21 to 70 days) fed the same diet the mothers received. In order to measure the neurons body profile and to quantify the number of neurons by area, they were stained by the nadh-diaphorase method. No significant changes were observed to the weight body in animals with autoclaved diet (p > 0.05). There was a decrease in the length of jejunum-ileum in rats treated with autoclaved diet (p > 0.05). The number of neurons by area increased approximately 10% in the rats supplied with autoclaved diet (p > 0.05). The neuron body profile area increased in the rats that received autoclaved diet and it was significant in the animals in weaning period. Nevertheless, all factors observed showed significant differences when related to animal age

Please read the abstract in the section 02back of this document / Thesis (DVSc)--University of Pretoria, 2010. / Surgery / unrestricted

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