A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / The role of enzyme‐assisted subcutaneous fluid administration (EASFA) in treating mild to moderate dehydration in pediatrics, geriatrics, and palliative care has been studied in developed countries. However, it has historically been underutilized due to widely available health care and alternative treatments, namely peripheral intravenous (IV) fluid administration. Fluid infusions in the subcutaneous tissue have a low risk of infection, are easy to administer, and have wide potential use. The use of EASFA in low resource settings to treat those with difficult IV access or where skilled healthcare workers are not as readily available could prove to be a live saving measure in many situations, including the care of patients in remote areas of the world, mass casualty events, or other disasters. Our objective was to determine if EASFA is a valid and appropriate technique to utilize in pediatric and elderly patients, and evaluate if it could be a safe and efficient way to provide fluid resuscitation in low resource settings. For this systematic review MEDLINE and Cochrane Library were searched from January 1950 to December 2015 to recover all available literature relevant to this topic. Studies that met the inclusion criteria were analyzed using Cohen’s D. This was calculated using the mean difference between intervention and control divided by the pooled standard deviation. For dichotomous outcome of the placement success rate the odds ratios were calculated with 95% confidence intervals. In reviewing 7 articles using Cohen’s D to compare mean differences to determine effect size, we found that catheter placement success rates and infusion rates were similar between EASFA and peripheral intravenous fluid administration. Additionally, it was found that the odds of correct initial needle placement was 7.19 times higher in EASFA versus intravenous administration. EASFA is a comparable alternative to intravenous fluid administration when delivering fluids to pediatric and elderly patients with mild to moderate dehydration. While infusion rates and total volume of fluids administered were similar, the high rate of success with placement of the subcutaneous catheter proves it to be more useful in some situations. Venous cannulation is difficult, even for a trained healthcare provider, and the ease of placement of subcutaneous catheters makes training lay people to administer subcutaneous fluids a possibility. Additionally, this type of fluid administration may lead to less psychological trauma to a child from multiple needle sticks, while still achieving a similar outcome of effective volume replacement. Based on the results of this study, further research is needed to evaluate the effectiveness of utilizing EASFA in low resource settings.

Introdução: O sucesso da cateterização da via biliar é de importância para o diagnóstico e terapêutica nas afecções biliopancreáticas nos procedimentos de colangiopancreatografia retrógrada endoscópica (CPRE) e está associado a complicações graves e mortalidade. O objetivo do estudo foi comparar o sucesso, perfil laboratorial e as complicações da técnica de fistulotomia papilar direta com o acesso cateter e fio-guia. Métodos: No período de julho de 2010 a maio de 2017 foram selecionados e randomizados para CPRE em dois grupos: cateterização com cateter e fioguia (Grupo I) e a fistulotomia papilar (Grupo II). As curvas de amilase, lipase e proteína C reativa (T0, 12 e 24 horas) e as complicações (pancreatite, sangramento e perfuração) foram avaliadas após CPRE. Resultados: Foram incluídos 102 pacientes (66 do sexo feminino e 36 do masculino, com idade média de 59,11±18,7 anos) e divididos em 51 pacientes para Grupo I e 51 no Grupo II. Os sucessos das cateterizações dos Grupos I e II foram de 76,47% e 100%, respectivamente (p=0,0002). Doze pacientes (23,53%) do Grupo I foram considerados pacientes de cateterização difícil e submetidos à fistulotomia papilar com sucesso no acesso biliar. Foram observadas 13,7% (2 perfurações e 5 pancreatites leves) e 2 % (1 paciente com perfuração e pancreatite) complicações nos Grupos I e II, respectivamente (p=0,062). Conclusão: A fistulotomia papilar demonstrou maior eficácia na cateterização da via biliar e com menor índice de amilasemia e lipasemia em comparação a cateterização com papilótomo e fio guia. As complicações foram semelhantes entre as duas técnicas / Background: The success of biliary tract cannulation is important for the diagnosis and treatment of biliopancreatic diseases in endoscopic retrograde cholangiopancreatography (ERCP) procedures. ERCP is associated with severe complications and mortality. The aim of the study was to compare the success, laboratory profile and complications of the direct papillary fistulotomy technique with standard catheter and guidewire access. Methods: In the period from July 2010 to May 2017, two groups were selected and randomized for ERCP: cannulation with catheter and guidewire (Group I) and papillary fistulotomy (Group II). The curves of amylase, lipase and C-reactive protein (T0, 12 and 24 hours) and complications (pancreatitis, bleeding and perforation) were evaluated after ERCP. Results: A total of 102 patients (66 females and 36 males, mean age 59.11 ± 18.7 years) were divided into 51 patients for Group I and 51 for Group II. The success of cannulation was 76.47% and 100%, in Groups I and II, respectively (p = 0.0002). Twelve patients (23.53%) of Group I were considered to have difficult cannulation and were submitted to fistulotomy with successful biliary access. There were 13.73% (2 perforations and 5 mild pancreatitis) and 2% (1 patient with perforation and pancreatitis) complications in Groups I and II, respectively (p=0,062). Conclusion: Papillary fistulotomy demonstrated greater efficacy in the bile duct cannulation and presented lower serum amylase and lipase compared with standard catheter and guidewire cannulation. Complications were similar in the two techniques

Introdução: O sucesso da cateterização da via biliar é de importância para o diagnóstico e terapêutica nas afecções biliopancreáticas nos procedimentos de colangiopancreatografia retrógrada endoscópica (CPRE) e está associado a complicações graves e mortalidade. O objetivo do estudo foi comparar o sucesso, perfil laboratorial e as complicações da técnica de fistulotomia papilar direta com o acesso cateter e fio-guia. Métodos: No período de julho de 2010 a maio de 2017 foram selecionados e randomizados para CPRE em dois grupos: cateterização com cateter e fioguia (Grupo I) e a fistulotomia papilar (Grupo II). As curvas de amilase, lipase e proteína C reativa (T0, 12 e 24 horas) e as complicações (pancreatite, sangramento e perfuração) foram avaliadas após CPRE. Resultados: Foram incluídos 102 pacientes (66 do sexo feminino e 36 do masculino, com idade média de 59,11±18,7 anos) e divididos em 51 pacientes para Grupo I e 51 no Grupo II. Os sucessos das cateterizações dos Grupos I e II foram de 76,47% e 100%, respectivamente (p=0,0002). Doze pacientes (23,53%) do Grupo I foram considerados pacientes de cateterização difícil e submetidos à fistulotomia papilar com sucesso no acesso biliar. Foram observadas 13,7% (2 perfurações e 5 pancreatites leves) e 2 % (1 paciente com perfuração e pancreatite) complicações nos Grupos I e II, respectivamente (p=0,062). Conclusão: A fistulotomia papilar demonstrou maior eficácia na cateterização da via biliar e com menor índice de amilasemia e lipasemia em comparação a cateterização com papilótomo e fio guia. As complicações foram semelhantes entre as duas técnicas / Background: The success of biliary tract cannulation is important for the diagnosis and treatment of biliopancreatic diseases in endoscopic retrograde cholangiopancreatography (ERCP) procedures. ERCP is associated with severe complications and mortality. The aim of the study was to compare the success, laboratory profile and complications of the direct papillary fistulotomy technique with standard catheter and guidewire access. Methods: In the period from July 2010 to May 2017, two groups were selected and randomized for ERCP: cannulation with catheter and guidewire (Group I) and papillary fistulotomy (Group II). The curves of amylase, lipase and C-reactive protein (T0, 12 and 24 hours) and complications (pancreatitis, bleeding and perforation) were evaluated after ERCP. Results: A total of 102 patients (66 females and 36 males, mean age 59.11 ± 18.7 years) were divided into 51 patients for Group I and 51 for Group II. The success of cannulation was 76.47% and 100%, in Groups I and II, respectively (p = 0.0002). Twelve patients (23.53%) of Group I were considered to have difficult cannulation and were submitted to fistulotomy with successful biliary access. There were 13.73% (2 perforations and 5 mild pancreatitis) and 2% (1 patient with perforation and pancreatitis) complications in Groups I and II, respectively (p=0,062). Conclusion: Papillary fistulotomy demonstrated greater efficacy in the bile duct cannulation and presented lower serum amylase and lipase compared with standard catheter and guidewire cannulation. Complications were similar in the two techniques

Bovine somatotropin (bST) is a protein synthesized at the base of the brain and released by the pituitary gland into the circulatory system. BST is transported by the circulatory system and absorbed only by cells of target organs that possess cell surface receptors for the protein (11, 41). Its effect is initiated via a protein receptor initiation and cyclic AMP cascade . This effect on the cell continues well past the degradation of the bST molecule. BST is likely transported into the cell, where it is degraded . Its constituent blocks, amino acids, are used to synthesize new proteins or converted to other metabolites such as sugars (1).

Arapaima gigas is the largest scaled freshwater fish in the world reaching over 250 kg. With growth rates of 10 kg+ within 12 months, A. gigas is considered as a promising candidate species for aquaculture development in South America. However, the lack of reproductive control in captivity is hindering the industry expansion. The work carried out in this doctoral thesis therefore aimed to better understand the species’ reproductive physiology, develop tools to identify gender and monitor gonad development, test hormonal therapies to induce ovulation and spawning and characterise the cephalic secretion for its potential roles in pheromone release and during parental care. Initially, a genomic study investigated the overall extent of polymorphism in A. gigas, which was found to be surprisingly low, with only 2.3 % of identified RAD-tags (135 bases long) containing SNPs. Then, a panel with 293 single nucleotide polymorphism (SNP) was used to characterise the genetic diversity and structure of a range of Amazon populations. Results revealed populations from the Amazon and Solimões appeared to be genetically different from the Araguaia population, while Tocantins population comprised individuals from both stocks. This data provided a tool for broodstock identification and future management. The PhD then aimed to evaluate the effects of slow-release mGnRH implants and different broodstock size pairings on maturation and spawning. Results showed that the implants stimulated the brain-pituitary-gonad axis resulting in increased plasma levels of testosterone (females) and 11-ketotestosterone in males, respectively regardless of pairing sizes. However, no spawning was observed. Results also showed the release of sex steroids with potential pheromonal action through the cephalic secretion, a biological fluid released from the adult head along the reproductive period. Thereafter, a non-surgical field endoscopy method was developed and validated for ovarian assessment and gender identification. The method was then used to describe the female gonopore and obtain biopsy of the ovary through cannulation which allowed the description of oogenesis in A. gigas. Importantly, oocytes obtained by cannulation confirmed that adult females under investigation were maturing with oocytes in final maturation stage but failed to ovulate/spawn. Another hormonal induction trial was therefore performed in which a combination of GnRHa (mGnRHa/sGnRHa) was used by injection to induce ovulation and spawning in selected maturing females with effects on oocyte maturation monitored post-induction through biopsy. However, this trial appeared to not be successful at inducing ovulation or spawning. Finally, the peptidome and proteome of the cephalic secretion was further characterised through the comparison between parental and non-parental fish. Results highlighted the complex role of this biological fluid including potential roles on the developing offspring during the parental care period. Overall, this doctoral thesis provided new basic and applied data on A. gigas reproduction and tools that can be used in future studies to better understand the environmental and hormonal control of oogenesis and spawning.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O oxigênio é importante não só por sua participação no metabolismo energético, mas também por sua conversão em derivados parcialmente reduzidos, as espécies reativas de oxigênio (ERO). ERO participam de funções importantes em diversas vias do metabolismo, entretanto, em concentrações desequilibradamente elevadas deflagram a peroxidação lipídica, processo deletério que forma aldeídos tóxicos, como o 4-hidroxi-2-nonenal (4-HNE). A manutenção de concentrações não deletérias das ERO é realizada por moléculas componentes do sistema antioxidante. Peixes podem ser expostos a grandes variações das concentrações de oxigênio, o que provoca ciclos oxidantes. A maioria dos estudos usa fígado e rim para avaliar estresse oxidante por meio de ensaios das atividades antioxidantes, o que requer o sacrifício dos animais. Contudo, o sangue sofre efeitos das ERO e avaliações no sangue podem permitir o estudo de antioxidantes no mesmo animal, sem a necessidade de sacrifício. Em consequência, foram nossos objetivos estabelecer uma técnica de cateterismo branquial em peixes, a padronização dos ensaios e a avaliação em sangue de componentes do sistema antioxidante de duas espécies de teleósteos em diferentes tensões de oxigênio. Pacus e tilápias foram avaliados em 6,0 mg de O2.L-1 e em hipoxia a 0,5 mg de O2.L-1 por 42 horas . Para os ensaios de hiperoxia os animais foram avaliados em 6,0 mg de O2.L-1, depois de 6 horas em 9,5 mg de O2.L-1 e depois de 30 horas de recuperação a 6,0 mg de O2.L-1. A utilização de materiais para o cateterismo de humanos permitiu a implantação de um acesso branquial. Infelizmente, houve formação de trombo após 24 horas. Mesmo assim, a observação de fluxo sanguíneo no interior da cânula e a sobrevida dos animais testados, confirmam a viabilidade da técnica. Verificamos em sangue uma maior atividade da enzima glutationa S-transferase (GST) sobre o 4-HNE em relação ao 1-cloro-2-dinitrobenzeno (CDNB). Isto reflete a importância de avaliações de atividade de enzimas, como a GST, sobre substratos endógenos. As respostas enzimáticas de tilápias mostraram-se mais sensíveis que as dos pacus quando comparadas em diferentes tensões de oxigênio. / Oxygen is important not only for their role in energy metabolism, but also for its conversion into partially reduced derivatives, the reactive oxygen species (ROS). ROS participate in important roles in several metabolic pathways, however, at concentrations lopsidedly high they trigger lipid peroxidation process to form deleterious toxic aldehydes such as 4-hydroxy-2-nonenal (4-HNE). Maintenance of non deleterious concentrations of ROS molecules is performed by components of the antioxidant system. Fish may be exposed to large variations in the concentrations of oxygen, which causes oxidative cycles. Most studies use liver and kidney to assess oxidative stress through antioxidant activities assay, which requires the sacrifice of animals. However, the blood undergoes effects of ROS and evaluations in blood may allow the study of antioxidants in the same animal, without the need of sacrifice. Consequently, our objectives were to establish a catheterization technique in fish gill, standardization of testing and evaluation of components of blood antioxidant system of two species of teleost in various oxygen tensions. Pacus and tilapias were evaluated at 6.0 mg O2.L-1 hypoxia and 0.5 mg O2.L-1 for 42 hours. For assays of hyperoxia animals were evaluated at 6.0 mg O2.L-1, after 6 hours at 9.5 mg O2.L-1 and after 30 hours recovery at 6.0 mg O2.L-1. The use of materials of human catheterization allowed the implantation of a gill access. Unfortunately, there was thrombus formation after 24 hours. Nevertheless, the observation of blood flow within the cannula and survival of the animals tested, confirm the viability of the technique. We found blood in a higher activity of glutathione S-transferase (GST) on the 4-HNE compared to 1-chloro-2-dinitrobenzene (CDNB). This reflects the importance of assessing the activity of enzymes, such as GST with endogenous substrates. The enzymatic responses of tilapia were more sensitive than those of pacus when compared to different oxygen tensions.

La thèse « Arrêt cardiaque réfractaire aux traitements pharmacologiques: quelle solution proposer pour améliorer la circulation systémique et cérébrale? » a montré que l'amélioration de la fonction circulatoire peut être obtenue à plusieurs étapes de la prise en charge de l'arrêt cardiaque. La première étude du travail, sous la forme d'une étude expérimentale à double randomisation, a montré que l'assistance circulatoire type extracorporeal life support ECLS apporte un bénéfice sur la mortalité dans la prise en charge de l'arrêt cardiaque réfractaire chez le cochon, et que l'adrénaline administrée en intraveineux lors de la résuscitation prolongée n'améliore pas la survie des animaux. La deuxième étude a montré que la canulation pour l'ECLS peut être réalisée rapidement par voie percutanée à l'aide d'un repérage échographique et en utilisant des guides rigides en salle de cathétérisme cardiaque chez les patients en arrêt cardiaque réfractaire, permettant l'initiation de l'ECLS dans des centres dotés de salle de cathétérisme sans chirurgie cardiovasculaire. La troisième étude a retrouvé que l'état de choc et le pH artériel<7,11 sont des critères pronostiques identifiant les patients qui, après un arrêt cardiaque, présentent une reprise d'une circulation spontanée mais sont à risque de décéder d'insuffisance circulatoire réfractaire au traitement par catécholamines. La quatrième étude à montré que la stabilisation de la fonction circulatoire par l'ECLS peut être suivie par une meilleure récupération de la fonction ventriculaire gauche en modulant la postcharge, par un dispositif pulsatile diminuant le débit de l'ECLS lors de la systole cardiaque. Enfin, l'optimisation de la circulation cérébrale nécessite en plus de l'optimisation de la circulation systémique, le contrôle de l'interaction entre la pression en gaz carbonique et le débit sanguin cérébral qui est amélioré par une normalisation de la pression en gaz carbonique en stratégie pH-stat. Cette stratégie mesure la pression en gaz carbonique à la température réelle du patient au lieu de la température de référence 37° comme dans la stratégie alpha-stat. L’ensemble de ces résultats, pouvant être appliqués à différentes étapes de la prise en charge d'un patient présentant un arrêt cardiaque, pourraient permettre l'amélioration du pronostic des patients. / The doctoral dissertation « Cardiac arrest refractory to pharmacological treatments : what solution to propose to improve systemic and cerebral circulation ? » showed that circulatory function improvement can be achieved at several stages of the management of cardiac arrest patients. The first study of the dissertation, a double randomization experimental study, showed that extracorporeal life support - ECLS type circulatory assistance improves mortality in refractory cardiac arrest in pigs, and intravenous administration of epinephrine during prolonged resuscitation does not improve survival.The second study showed that cannulation for ECLS can be performed rapidly by the percutaneous technique using echography guidance and stiff wires in the catheterization laboratory in refractory cardiac arrest patients allowing for ECLS initiation in centres with catheterization laboratories but without cardiovascular surgery.The third study found that circulatory shock and arterial pH<7.11 are prognostic criteria identifying patients who, after a cardiac arrest, have return of spontaneous circulation but are at risk of death from circulatory failure refractory to catecholamine treatment.The fourth study showed that hemodynamic stabilization by ECLS can be followed by a better recovery of the left ventricular function by modulating afterload using a pulsatile device lowering ECLS output during systole.Finally, optimization of the cerebral circulation requires besides optimization of the systemic circulation, the control of the interaction between carbon dioxyde partial pressure and cerebral circulatory output, which is improved by normalizing carbon dioxyde partial pressure in pH-stat strategy. This strategy measures partial pressure of carbon dioxyde at the real temperature of the patients instead of the theoretical 37° reference temperature as in alpha-stat strategy.All these results can be applied at different stages of the management of cardiac arrest patients and may improve their prognosis.

Background: Despite the successful development in cardiac surgery, cerebrovascular accidents (CVA) remain a devastating complication. Aortic atherosclerosis has been identified as a major risk factor for CVA. The present thesis addresses this question in relation to aortic manipulation during cardiac surgery, being divided into a clinical (I-II) and an experimental part (III-V). Material and methods: Consecutive cardiac surgery cases (n=2641) were analyzed. Patients with CVA were extracted from a database designed to monitor clinical symptoms. Patient records were used to confirm clinical data and diagnosis. Subdivision was made into three groups: control subjects, immediate, and delayed CVA, being analyzed for neurological symptoms (I). Patients with CVA who also had been investigated with computer tomography (CT) (n=77) were further evaluated in terms of hemispheric and vascular distribution of lesions. The CT-findings were compared with CVA symptoms (II). An aortic perfusion model was developed using cadaver aorta onto which multiple cross-clamp manipulations were applied (III). Washout samples of perfusate were analyzed by computerized image processing and with subdivision into different particle spectra. The model was further developed with the introduction of intraluminal manipulation from cannula and intra-aortic filter (IV). A technique for macro-anatomic mapping of plaque distribution of cadaver thoracic aorta was developed (V). Variation in plaque density was analyzed in different anatomical segments, monitored by digital image analysis. Hazards associated with surgical manipulation were studied by superimposing cannulation and cross-clamp sites onto the aortic maps in a blinded fashion. Results: The incidence of immediate and delayed CVA was 3.0% and 0.9%, respectively. Aortic quality was a strongly associated with immediate but not delayed CVA. Left-sided symptoms of immediate CVA were significantly more frequent than of the contra-lateral side. Positive signs on CT were seen in 66% of the CVA patients. Right-hemispheric lesions were more frequent compared with the contra-lateral side and the middle-cerebral artery territory dominated. Aortic cross-clamping produced a substantial output of particulate matter. Manipulation by intra-aortic filter produced a significant washout of embolic particles that escaped the filter, although some particles were captured. Cannulation was an additional source of embolic material. In terms of plaque distribution was the anterior wall of the ascending part and arch of the aorta more affected than its posterior side. However, observing a plaque in the anterior wall of this aortic segment predicted to 83% a concomitant plaque in the posterior wall. Increased age correlated positively with plaque density. The theoretical chance of interfering with a plaque during cannulation and/or clamp positioning was 45.8%. Conclusions: Both CT scans and clinical symptoms confirmed that CVA after cardiac surgery had a right-hemispheric predominance. The perfusion model resulted in a profound output of material during cross-clamp maneuvers. The intra-aortic filter successfully collected particles but also generated embolic debris on its own. Aortic cannulation was an additional source of embolic debris. Plaques were frequently found in the cadaveric aorta, and there was a high risk of plaque interference during surgical manipulation. As expected, plaque density was age-dependent.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O oxigênio é importante não só por sua participação no metabolismo energético, mas também por sua conversão em derivados parcialmente reduzidos, as espécies reativas de oxigênio (ERO). ERO participam de funções importantes em diversas vias do metabolismo, entretanto, em concentrações desequilibradamente elevadas deflagram a peroxidação lipídica, processo deletério que forma aldeídos tóxicos, como o 4-hidroxi-2-nonenal (4-HNE). A manutenção de concentrações não deletérias das ERO é realizada por moléculas componentes do sistema antioxidante. Peixes podem ser expostos a grandes variações das concentrações de oxigênio, o que provoca ciclos oxidantes. A maioria dos estudos usa fígado e rim para avaliar estresse oxidante por meio de ensaios das atividades antioxidantes, o que requer o sacrifício dos animais. Contudo, o sangue sofre efeitos das ERO e avaliações no sangue podem permitir o estudo de antioxidantes no mesmo animal, sem a necessidade de sacrifício. Em consequência, foram nossos objetivos estabelecer uma técnica de cateterismo branquial em peixes, a padronização dos ensaios e a avaliação em sangue de componentes do sistema antioxidante de duas espécies de teleósteos em diferentes tensões de oxigênio. Pacus e tilápias foram avaliados em 6,0 mg de O2.L-1 e em hipoxia a 0,5 mg de O2.L-1 por 42 horas . Para os ensaios de hiperoxia os animais foram avaliados em 6,0 mg de O2.L-1, depois de 6 horas em 9,5 mg de O2.L-1 e depois de 30 horas de recuperação a 6,0 mg de O2.L-1. A utilização de materiais para o cateterismo de humanos permitiu a implantação de um acesso branquial. Infelizmente, houve formação de trombo após 24 horas. Mesmo assim, a observação de fluxo sanguíneo no interior da cânula e a sobrevida dos animais testados, confirmam a viabilidade da técnica. Verificamos em sangue uma maior atividade da enzima glutationa S-transferase (GST) sobre o 4-HNE em relação ao 1-cloro-2-dinitrobenzeno (CDNB). Isto reflete a importância de avaliações de atividade de enzimas, como a GST, sobre substratos endógenos. As respostas enzimáticas de tilápias mostraram-se mais sensíveis que as dos pacus quando comparadas em diferentes tensões de oxigênio. / Oxygen is important not only for their role in energy metabolism, but also for its conversion into partially reduced derivatives, the reactive oxygen species (ROS). ROS participate in important roles in several metabolic pathways, however, at concentrations lopsidedly high they trigger lipid peroxidation process to form deleterious toxic aldehydes such as 4-hydroxy-2-nonenal (4-HNE). Maintenance of non deleterious concentrations of ROS molecules is performed by components of the antioxidant system. Fish may be exposed to large variations in the concentrations of oxygen, which causes oxidative cycles. Most studies use liver and kidney to assess oxidative stress through antioxidant activities assay, which requires the sacrifice of animals. However, the blood undergoes effects of ROS and evaluations in blood may allow the study of antioxidants in the same animal, without the need of sacrifice. Consequently, our objectives were to establish a catheterization technique in fish gill, standardization of testing and evaluation of components of blood antioxidant system of two species of teleost in various oxygen tensions. Pacus and tilapias were evaluated at 6.0 mg O2.L-1 hypoxia and 0.5 mg O2.L-1 for 42 hours. For assays of hyperoxia animals were evaluated at 6.0 mg O2.L-1, after 6 hours at 9.5 mg O2.L-1 and after 30 hours recovery at 6.0 mg O2.L-1. The use of materials of human catheterization allowed the implantation of a gill access. Unfortunately, there was thrombus formation after 24 hours. Nevertheless, the observation of blood flow within the cannula and survival of the animals tested, confirm the viability of the technique. We found blood in a higher activity of glutathione S-transferase (GST) on the 4-HNE compared to 1-chloro-2-dinitrobenzene (CDNB). This reflects the importance of assessing the activity of enzymes, such as GST with endogenous substrates. The enzymatic responses of tilapia were more sensitive than those of pacus when compared to different oxygen tensions.

El presente estudio de caso tuvo como objetivo describir, analizar y comprender las experiencias de las enfermeras en la canalización de vías endovenosas en pacientes pediátricos en un hospital 2019, con un enfoque cualitativo. La muestra estuvo conformada por doce enfermeras que laboran en el servicio de pediatría del Hospital Regional, se determinó por saturación y redundancia incluyendo los criterios de inclusión y exclusión, se utilizó la técnica de recolección de datos, entrevista semiestructurada a profundidad, para el procesamiento de la información se empleó el método del análisis temático. En todo momento se cumplió con los criterios éticos y el rigor científico de la investigación. Entre los resultados se obtuvo que las enfermeras reconocen la expresión de sentimientos positivos a través de gratas experiencias vividas en su quehacer diario durante la canalización endovenosa, lo cual les genera no solo satisfacción profesional y personal sino el bienestar que logra en el paciente haciendo menos daño con menos venopunciones. Se encontró que las enfermeras viven experiencias difíciles y complicadas, les permite generar habilidades como el autocontrol, el entusiasmo, la automotivación, la empatía y dotarlas de defensas para la reacción positiva a la tensión y al estrés; y entre sus experiencias difíciles recurren a la ayuda espiritual como es Dios buscando fe y fortaleza; en la familia del paciente pediátrico buscan el soporte para generar un ambiente de confianza al momento de realizar la canalización y que sea más rápida y menos dolorosa para el paciente. / The objective of this case study was to describe, analyze and understand the experiences of nurses in the cannulation of intravenous lines in pediatric patients in a hospital in 2019, with a qualitative approach. The sample was made up of twelve nurses who work in the pediatric service of the Regional Hospital, it was determined by saturation and redundancy including theinclusion and exclusion criteria, the data collection technique, semi-structured in-depth interview, was used for the processing of The thematic analysis method was used to collect the information. The ethical criteria and scientific rigor of the research were met at all times. Amongthe results, it was obtained that nurses recognize the expression of positive feelings through pleasant experiences in their daily work during intravenous cannulation, which generates not only professional and personal satisfaction but also the well-being that it achieves in the patient,doing less harm. with fewer venipunctures. It was found that nurses live difficult and complicated experiences, allowing them to generate skills such as self-control, enthusiasm, self-motivation, empathy and providing them with defenses for a positive reaction to tension and stress; and among their difficult experiences they turn to spiritual help such as God seeking faithand strength; The family of the pediatric patient seeks support to generate an environment of trust when performing the canalization and to make it faster and less painful for the patient.