Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 3 uppsatser.

Diss. (sammanfattning) Umeå : Univ., 2003. / Härtill 6 uppsatser.

Orientador: César Tadeu Spadella / Resumo: Nas ressecções pancreáticas por pancreatite crônica, o pâncreas remanescente poderá sofrer novos surtos de pancreatite, em gravidade variável. Nas ressecções por tumores ou pancreatite, a mais comum complicação é a fístula pancreática, com suas conseqüentes morbidade e mortalidade. Nos transplantes pancreáticos, a drenagem da parte exócrina do enxerto para o intestino ou para a bexiga, além das peculiaridades técnicas da execução, não é isenta de diversas complicações. Visando evitar ou atenuar tais conseqüências e simplificar a técnica cirúrgica, têm sido usadas outras abordagens para o tratamento do coto/enxerto pancreático: drenagem livre das secreções com o ducto pancreático aberto, ligadura ductal e oclusão do ducto com polímeros. O propósito de nossa investigação foi estudar os efeitos clínicos, laboratoriais e histopatológicos destes procedimentos sobre os componentes endócrino e exócrino do pâncreas em coelhos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: After pancreatic ressections due to chronic pancreatitis the remnant pancreas can lead to new outbreaks of pancreatitis in variable degrees of severity. After the resections by tumors or pancreatitis, the most common complication are the pancreatic fistulas with their resultant morbidity and mortality. In the pancreas transplantation the bowel or bladder drainage of the exocrine part of the graft, beyond the technical peculiarities of the execution, is not exempt of several complications. In order to avoid or reduce such consequences and trying to simplify the surgical technique, there have been used other approaches for the treatment of the pancreatic stump/graft: free drainage of the secretions with the duct left open, ductal ligature and duct occlusion with polymers. The proposal of our investigation was to study the clinical, laboratorial and histopathological effects of these procedures in the endocrine and exocrine compounds of the rabbit pancreas... (Complete abstract, click electronic address below) / Doutor

Made available in DSpace on 2015-01-26T13:21:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-14Bitstream added on 2015-01-26T13:30:41Z : No. of bitstreams: 1 000793012.pdf: 590115 bytes, checksum: ed882cd22177020eacb824774d3bea52 (MD5) / Introdução - Apesar de controvérsias, a máscara laríngea passou a ser utilizada em larga escala em laparoscopias. Nas ginecológicas, em especial, que têm no aumento da pressão intra-abdominal, associado à posição de céfalo-declive empregada durante o procedimento, fatores com potencial de risco de provocar regurgitação de conteúdo gástrico, com possibilidade de comprometimento de vias aéreas, faz-se necessária uma avaliação para a ocorrência de tal fenômeno. Objetivo - Avaliar a segurança do uso da máscara laríngea, em laparoscopia ginecológica, com relação ao risco de regurgitação de conteúdo gástrico, medindo o pH das secreções de hipofaringe, durante o procedimento anestésico-cirúrgico. Método - Foram avaliadas 80 pacientes submetidas à anestesia geral para laparoscopia ginecológica, com acesso a via aérea garantida pelo uso da máscara laríngea ProSeal (MLA-ProSeal). As secreções da hipofaringe foram coletadas por aspiração através do tubo de drenagem esofágica, para medida do pH, em vários momentos do ato anestésico-cirúrgico. Utilizamos as fitas medidoras de pH de 2 a 9 – Merck, Darmstadt – Alemanha e um ph-metro de bancada foi utilizado em caso de dúvidas. O pH ≤ 4,1 foi considerado como positivo para regurgitação de conteúdo gástrico. Resultados - Após análise das medidas do pH das secreções de hipofaringe, não se encontrou nenhum valor de pH ≤ 4,1. O pH das secreções variou com médias de 6,34 a 6,50 nos diversos momentos medidos, compatível com o pH normal da saliva. Conclusão - Com os resultados obtidos, concluiu-se que a máscara laríngea ProSeal é uma alternativa segura para a realização do ato anestésico em cirurgia laparoscópica, nos pacientes que não apresentem fatores de risco para regurgitação de conteúdo gástrico / Introduction: Although controversial, the laryngeal mask is now widely used for laparoscopies. In gynecological laparoscopy, in particular, there is an increase in the intra-abdominal pressure associated with the head-down position used during the procedure and an increase in the potential risk factors for the regurgitation of gastric contents with the potential to compromise the airways, and therefore, the occurrence of such phenomena during gynecological laparoscopy needs to be evaluated. Objectives - To evaluate the safety of using a ProSeal laryngeal mask airway (LMA-P) during gynecological laparoscopy, assessing the risk of regurgitation of gastric contents by measuring the pH of secretions in the hypopharynx during the anesthetic/surgical procedure. Methods - In total, 80 patients were evaluated who were under general anesthesia for gynecological laparoscopy in which airway access was maintained using a ProSeal laryngeal mask airway. Secretions in the hypopharynx were collected by aspiration using an esophageal drainage tube to measure their pH at various times during the anesthetic/surgical procedure. We used pH test strips, pH 2-9 (Merck, Darmstadt, Germany), and in case of any doubts, a pH meter was also used. A pH of ≤ 4.0 was considered positive for the regurgitation of gastric contents. Results - None of the pH measurements of analyzed secretions in the hypopharynx had a pH of ≤ 4.0. The mean pH of the secretions varied from 6.34 for the lower means to 6.50 for the higher means when measured at different time points, which are comparable to the normal pH of saliva. Conclusion - From these results, we conclude that the ProSeal laryngeal mask airway is a safe alternative for anesthesia during laparoscopic surgery for patients without risk factors for the regurgitation of gastric contents

Orientador: Norma Sueli Pinheiro Módolo / Banca: Leandro Gobbo Braz / Banca: Vera Lúcia Fernandes de Azevedo / Resumo: Introdução - Apesar de controvérsias, a máscara laríngea passou a ser utilizada em larga escala em laparoscopias. Nas ginecológicas, em especial, que têm no aumento da pressão intra-abdominal, associado à posição de céfalo-declive empregada durante o procedimento, fatores com potencial de risco de provocar regurgitação de conteúdo gástrico, com possibilidade de comprometimento de vias aéreas, faz-se necessária uma avaliação para a ocorrência de tal fenômeno. Objetivo - Avaliar a segurança do uso da máscara laríngea, em laparoscopia ginecológica, com relação ao risco de regurgitação de conteúdo gástrico, medindo o pH das secreções de hipofaringe, durante o procedimento anestésico-cirúrgico. Método - Foram avaliadas 80 pacientes submetidas à anestesia geral para laparoscopia ginecológica, com acesso a via aérea garantida pelo uso da máscara laríngea ProSeal (MLA-ProSeal). As secreções da hipofaringe foram coletadas por aspiração através do tubo de drenagem esofágica, para medida do pH, em vários momentos do ato anestésico-cirúrgico. Utilizamos as fitas medidoras de pH de 2 a 9 - Merck, Darmstadt - Alemanha e um ph-metro de bancada foi utilizado em caso de dúvidas. O pH ≤ 4,1 foi considerado como positivo para regurgitação de conteúdo gástrico. Resultados - Após análise das medidas do pH das secreções de hipofaringe, não se encontrou nenhum valor de pH ≤ 4,1. O pH das secreções variou com médias de 6,34 a 6,50 nos diversos momentos medidos, compatível com o pH normal da saliva. Conclusão - Com os resultados obtidos, concluiu-se que a máscara laríngea ProSeal é uma alternativa segura para a realização do ato anestésico em cirurgia laparoscópica, nos pacientes que não apresentem fatores de risco para regurgitação de conteúdo gástrico / Abstract: Introduction - Although controversial, the laryngeal mask is now widely used for laparoscopies. In gynecological laparoscopy, in particular, there is an increase in the intra-abdominal pressure associated with the head-down position used during the procedure and an increase in the potential risk factors for the regurgitation of gastric contents with the potential to compromise the airways, and therefore, the occurrence of such phenomena during gynecological laparoscopy needs to be evaluated. Objectives - To evaluate the safety of using a ProSeal laryngeal mask airway (LMA-P) during gynecological laparoscopy, assessing the risk of regurgitation of gastric contents by measuring the pH of secretions in the hypopharynx during the anesthetic/surgical procedure. Methods - In total, 80 patients were evaluated who were under general anesthesia for gynecological laparoscopy in which airway access was maintained using a ProSeal laryngeal mask airway. Secretions in the hypopharynx were collected by aspiration using an esophageal drainage tube to measure their pH at various times during the anesthetic/surgical procedure. We used pH test strips, pH 2-9 (Merck, Darmstadt, Germany), and in case of any doubts, a pH meter was also used. A pH of ≤ 4.0 was considered positive for the regurgitation of gastric contents. Results - None of the pH measurements of analyzed secretions in the hypopharynx had a pH of ≤ 4.0. The mean pH of the secretions varied from 6.34 for the lower means to 6.50 for the higher means when measured at different time points, which are comparable to the normal pH of saliva. Conclusion - From these results, we conclude that the ProSeal laryngeal mask airway is a safe alternative for anesthesia during laparoscopic surgery for patients without risk factors for the regurgitation of gastric contents / Mestre

The multiple functions of the pineal gland have been collectively interpreted as constituting a general anti-stressogenic role. The adrenal glands play a central role in maintaining homeostasis. The major neuroendocrine consequence of long-term stress is elevated circulating glucocorticoid levels. In this study, the effect of chronic, oral hydrocortisone treatment on pineal biochemistry was investigated in male Wi star rats of the albino strain. The results show that seven days of oral hydrocortisone treatment endows the pineal gland with the ability to increase melatonin synthesis in organ culture. The increase is accompanied by a rise in NAT activity, cyclic AMP levels and enhanced specific binding to the pineal B-adrenergic receptors. It appears that hydrocortisone sensitizes the pineal gland to stimulation by B-adrenergic agonists. thus rendering the pineal more responsive to B-adrenergic agonists. Further studies were directed at demonstrating an anti-stressogenic function for the pineal gland by investigating whether the principal pineal indole, melatonin. could protect against the deleterious effects of elevated. circulating drocortisone levels. The results show that chronic, oral hydrocortisone treatment significantly increases liver tryptophan pyrrolase activity. The catabolism of tryptophan by tryptophan pyrrolase is an important determinant of tryptophan availability to the brain, and therefore, brain serotonin levels. The findings show that melatonin inhibits basal and hydrocortisone-stimulated liver tryptophan pyrrolase apoenzyme activity in a dose-dependent manner. This inhibition suggests that melatonin may protect against excessive loss of tryptophan from circulation and against deficiencies in the cerebral serotinergic system which are associated with mood and behavioural disorders. It was shown that another deleterious effect of chronic hydrocortisone treatment is a significant increase in the number of glutamate receptors in the forebrain of male Wistar rats. The increase in receptor number observed in this study is probably due to an increase in the synthesis of glutamate receptors and is associated with a marked reduction in the affinity of the glutamate receptors for glutamate. possible to demonstrate an receptor number or the For practical reasons, it was not effect of melatonin on either glutamate affinity of glutamate receptors for glutamate in rat forebrain membranes. In view of the neurotoxic effect of glutamate in the eNS, the functional significance of recently described glutamate receptors in the pineal gland was investigated. The results show that 10-4 M glutamate significantly inhibits the isoprenaline-stimulated synthesis of N-acetylserotonin and melatonin in organ culture when the pineal glands were pre-incubated with glutamate for 4 hours prior to stimulation with isoprenalin and when glutamate and isoprenaline were administered together in vitro. GABA, a glutamate metabolite could not mimic the decrease in isoprenalinestimulated melatonin, and it is likely that the observed effects were directly attributed to glutamate. Incubation of the pineal gland with 10-4 M glutamate in organ culture did not affect HIOMT activity in pineal homogenates, but significantly elevated both basal and isoprenaline-stimulated NAT activity. It was concluded that glutamate only inhibits melatonin synthesis in intact pineal glands and not in pineal homogenates. The present study has provided further support for an interaction between the pineal and the adrenal glands. There is an ever increasing likelihood that melatonin is an anti-stressogenic hormone and that the pineal gland may have a protective role to play in the pathology of stress-related diseases.

The pineal gland has become the subject of considerable investigation as it provides a productive experimental model for studying circadian rhythms and regulation of end organs. In the rat, the pineal gland provides a convenient model for investigating the noradrenergic receptor system and the effects of various drugs on this system. The effect of appetite suppressants on the rat pineal gland function is described. Appetite suppressants increase melatonin synthesis in organ cultures of rat pineal glands. This effect appears to be mediated by noradrenaline acting on β-adrenoceptors on the pinealocyte membrane. When β-adrenoceptors are blocked, the appetite suppressant-induced rise in melatonin synthesis is prevented. Depletion of noradrenaline in sympathetic nerve terminals also prevented the appetite suppressant-induced rise in melatonin synthesis. Activation of β-adrenoceptors is followed by a rise in N-acetyltransferase activity via a cyclic adenosine monophosphate second messenger system. The effect of appetite suppressants on the activity of liver tryptophan pyrrolase was also investigated. The activity of this enzyme is an important determinant of tryptophan availability to the brain and consequently of brain serotonin levels. The results show that appetite suppressants inhibit both holoenzyme and total enzyme activities of tryptophan pyrrolase. This finding suggests that appetite suppressants may act by inhibiting tryptophan pyrrolase activity thereby increasing brain serotonin, a phenomenon known to be associated with anorexia. There are two possible mechanisms by which appetite suppressants inhibit tryptophan pyrrolase activity. Firstly, these agents, being drugs of dependence, may increase liver NADPH concentrations which inhibit pyrrolase activity. Secondly, appetite suppressants may act on the pineal gland to stimulate melatonin synthesis. Melatonin inhibits pyrrolase activity in a dose-dependent manner. This inhibition will elevate plasma tryptophan levels which result in a rise in brain serotonin synthesis. The present study suggests a possible relationship between the pineal gland and appetite centres in the hypothalamus. Melatonin may have a direct effect on appetite centres since food restriction is associated with an increased melatonin binding in the hypothalamus. If this possible relationship can be extended, melatonin can open new possibilities for the control of food intake and consequently, of pathological obesity.

Total parenteral nutrition (TPN) provides an experimental situation where adequate nutrition is provided intravenously, bypassing the gastrointestinal tract. Under these conditions the importance of orally ingested nutrients in the control of gastric and pancreatic endocrine secretion can be assessed. The objectives of this thesis were two-fold. First, to examine the effects of TPN on the enteroinsular axis component of insulin secretion. Second, to study the importance of orally ingested nutrients in the regulation of gastric hormone secretion using the TPN rat model. In order to carry out these objectives, techniques for TPN and enteral feeding (TEN) of the rat were first developed. A dietary regimen for use in TPN and TEN rats was formulated from commercially-available, human TPN components. Under most circumstances, the TPN/TEN regimen met or exceeded the nutritional requirements for growing rats, as determined by the National Research Council (1978). Hematological analysis revealed few side effects of — intravenous or intragastric feeding. Parenterally and enterally-fed animals demonstrated comparable weight gain to that of a control group (ORAL) fed a rat chow (#5012, Ralston Purina) diet ad libitum. In addition, both TPN and TEN animals appeared healthy after the 7-day infusion period. These studies indicated that the infusion formulation was suitable for chronic intravenous and intragastric feeding. In the first series of experiments, the effects of TPN and TEN on the hormonal component of the enteroinsular axis were studied. TPN animals exhibited hyperinsulinemia and mild hyperglycemia. Conversely, TEN animals exhibited normal plasma glucose and immunoreactive insulin (IRI) concentrations. These data suggested that enterally delivered nutrients were assimilated with greater efficiency than intravenously administered nutrients. It was hypothesized that gut factors normally released by oral food intake facilitated the disposal of nutrients by hepatic and/or peripheral tissues. During the infusion period, TPN animals exhibited chronically depressed circulating IR-gastric inhibitory polypeptide (GIP) levels, in contrast to TEN animals where IR-GIP was elevated. Seven days of TPN or TEN resulted in no change in fasting plasma IRI or IR-GIP levels. However, an exaggerated insulin response to an oral glucose challenge (OGC) occurred after TPN, while the glucose response was reduced. The insulin response from the perfused pancreata of TPN animals to a GIP gradient was 20% and 40% greater than from ORAL and TEN pancreata respectively. Shorter periods of TPN (3 and 5-day periods) indicated that the hypersensitivity of the pancreas to GIP was a progressive condition, increasing with longer periods of infusion. Immunocytochemical and morphometric analysis revealed no differences in the jejunal GLP-cell population after chronic (7-day) intravenous or intragastric feeding. In addition, these routes of feeding had no effect on pancreatic islet area or endocrine cell composition of the islets. Based on these results, it was hypothesized that the increased B-cell sensitivity to GIP may have been causally related to the exposure of the pancreas to chronically low plasma GIP levels during the infusion period. To further test this hypothesis, chronically depressed plasma GIP levels, observed during TPN, were elevated by exogenous GIP infusion to levels seen in TEN rats. Chronic GIP —treatment in TPN animals (TPN-GIP) resulted in normalization of the insulin response to an OGC and in the in vitro insulin response of the isolated pancreas to GIP. These data were taken as further evidence that B-cell sensitivity to GIP was affected by ambient plasma GIP levels, and it was hypothesized that changes in sensitivity may be mediated by alteration at the receptor or post-receptor level. The effect of TPN on nutrient and neuronally mediated insulin release was also investigated. During TPN, metabolites and neuronal elements provided the main stimulus for insulin release, since hormonal components of the enteroinsular axis remained inactive. The present experiments indicated that the B-cell was hypersensitive to glucose, vagal stimulation and the cholinergic agonist methacholine, but normally sensitive to vasoactive intestinal polypeptide (VIP) and the insulinotropic amino acid arginine. These results indicated that TPN was associated with an increased B-cell sensitivity to specific hormonal, nutritive and neuronal stimuli. It was hypothesized that an increased B-cell sensitivity to these specific stimuli contributed to hyperinsulinemia observed in TPN animals during the infusion period, and to the exaggerated insulin response observed after an oral glucose challenge. Total parenteral nutrition also provided an experimental situation in which to study the importance of gastric nutrients in the regulation of Gl-hormone secretion. TPN resulted in a rapid and progressive depletion of circulating gastrin levels. G-cell secretory activity in vivo under basal and stimulatory conditions was also reduced by TPN. This condition persisted in vitro in the isolated stomach. The antral G-cell population was shown to decrease progressively with longer TPN periods, but G-cell hypoplasia and reductions in antral gastrin content were less dramatic than reductions in G-cell secretory activity. It was hypothesized that reductions in G-cell secretory activity were in part causally related to antral G-cell hypoplasia. The present data further suggested, however, that mechanisms which control synthesis and/or secretion within G-cells may have also been impaired, since various stimulants of gastrin release could not reverse gastrin hyposecretion observed during basal periods. Gastrin hyposecretion also could not be reversed by chronic bombesin administration, but was reversed by a 6-day period of oral — refeeding, indicating that the presence of nutrients in the gastric lumen was the primary regulator of tissue gastrin levels and G-cell secretory activity. The gastric D-cell was much less affected by the absence of nutrients in the gastric lumen than was the G-cell, and antral somatostatin hypersecretion may have contributed to G-cell hyposecretion. The experiments presented in this thesis indicated that total parenteral nutrition had marked effects on both B- and G-cell secretory activity. These studies clearly demonstrated the importance of enteral feeding in the maintenance of normal pancreatic and gastrointestinal endocrine secretion. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

All animals interact in some way with microbes during their growth and development. These interactions often prove harmful as animals find themselves exposed to pathogens or the harmful by-products of microbial growth. For many animals avoidance of microbes is difficult or impossible, particularly for species that obligately utilise microbe-laden resources during reproduction. Larvae of the carrion beetle Nicrophorus vespilloides are significantly harmed by the bacteria they encounter during their development on decomposing vertebrate carcasses. However, these effects can be partially ameliorated by parental investment into behaviours which reduce the effects of microbial exposure. In this thesis I focus on two aspects of N. vespilloides response to microbial competition. First I investigate the composition and fitness effects of the application of exogenous secretions by parents and larvae to their breeding resource. This behaviour in parents has long been hypothesized to form an important part of the antimicrobial component of parental care, but this has not been rigorously tested. Nor, prior to my work, has any experimental attention been given to the possibility that larvae also contribute to antimicrobial production while on the carcass. Second I investigate the late-life and intergeneration effects of microbial exposure during development on a range of beetle life history traits including larval body size, brood size and immune function and survival in response to bacterial challenge. My results demonstrate the following: i) that larval N. vespilloides suffer significant harm from microbial competition during development that manifests itself in several ways, e.g. reduced body size, increased susceptibility to infection, or reduced ability of mothers to provide post hatch maternal care; ii) that the effects of microbial competition can be mitigated by parental behaviours that reduce the level of microbial contamination on a resource. Specifically, mothers apply antimicrobial secretions containing lysozyme to the carcass which kills bacteria and significantly increases larval survival; iii) that larvae are not totally reliant on their parents for antimicrobial protection because they too can secrete exogenous antimicrobial compounds similar in activity to their parents and which significantly increase larval fitness; iv) the effects of microbial competition can result in transgenerational effects that reduce offspring fitness but which can also provide context-dependent benefits by increasing larval survival when post-hatch parental care is poor and following challenge with pathogenic infection. By developing on and consuming carrion Nicrophorus larvae and other specialist scavengers experience an extreme example of the challenges faced by opportunistic carrion users or animals that for any reason utilise microbially contaminated resources. This makes them ideal model organisms to study adaptations to the presence of complex microbial communities that may contain both pathogens and toxin producers.

No description available.