A hemostasia é um evento biológico passível de ser avaliado e estudado, assim como seus distúrbios. Há situações durante a anestesia que podem cursar com alterações hemostáticas culminando com aumento do sangramento ou até mesmo hemorragias graves. Os tempos de coagulação têm recebido especial atenção tendo-se em vista os diferentes contratempos hemostáticos que pode ocorrer durante o procedimento anestésico-cirúrgico. Sendo assim, nesse estudo buscou-se estabelecer os valores padrões para tempo de protrombina (TP) e de tromboplastina parcial ativada (TTPA) para cães submetidos a diferentes procedimentos cirúrgicos. Foram estudados 50 cães hígidos para padronização dos valores de TTPA e TP utilizando aparelho automático. Os valores de TTPA estavam dentro dos valores de normalidade da literatura (6,9 a 17,6 segundos) e valores de TP discretamente maiores (de 6,65 a 12,8 segundos). Foram estudadas 20 cadelas classificadas como ASA I e 18 cães ASA II e III. Nestes animais observaram-se aumentos significativos de valores de TTPA (de 12,04 para 14,29 segundos em ASA I, com P<0,0378; e de 13,4 para 15,11 segundos nos cães ASA II e III, P<0,0067) e de TP (de 8,36 para 9,7 segundos em ASA I, P<0,0323; e de 8,32 para 9,34 segundos nos caes ASA II e III, P< 0,0084) entre os momentos pré e pós-anestésicos Estes aumentos acompanham quedas da pressão coloidosmótica, indicando que o processo de anestesia, cirurgia e fluidoterapia causam hemodiluição, e conseqüente aumento nos tempo de coagulação. / Hemostasis is a biological event that could be evaluated and studied, just like yours disturbs. There are situations in to anesthetic procedures that could curse with hemostatics disturbs causing bleeding increase or even critical blood loss. The blood clotting times have been received special attention because different hemostatic setbacks that could occur during the anesthetic and surgical procedures. This way, this study look for establish the values for reference to protrombine time (PT) and to activated partial tromboplastin time (APTT) for dogs. Were studied 50 healthy dogs to standardize the values of PT and APTT utilizing an automatic instrument. The APTT values was in agreement with the literature values (6,9 to 17, 6 seconds), and the PT values was discret increased when compared with literature (from 6,65 to 12,8 seconds). Was studied 20 bitches classifieds as ASA I and 18 dogs classifieds as ASA II and III. In this animals observed significant increase values of APTT (from 12,04 to 14,29 seconds in the ASA I, P<0,0378; and from 13,4 to 15,11 seconds in the dogs ASA II and III, P<0,0067) and of PT (from 8,36 to 9,7 seconds in ASA I, P<0,0323; and from 8,32 to 9,34 seconds in the ASA II and III dogs) between the pre and post anesthetic moments. These increases attendance decease in the colloid osmotic pressure, indicating that the anesthetic, surgical and fluid therapy procedures can cause hemodilution, and consequent increase in the blood clotting times.

No description available.

A tolerância ou pré-condicionamento é uma estratégia de defesa do hospedeiro que reduz o impacto negativo da infecção na saúde. Diminui a susceptibilidade a danos teciduais, causados pelos patógenos ou pela resposta imune. Um desbalanço no fluido e pressão osmótica intra e extracelular causa o estresse osmótico e liberação de mediadores inflamatórios. A solução salina hipertônica (SSH) tem sido utilizada na ressuscitação volêmica, mostrando-se benéfica em pacientes com danos cerebrais e pulmonares (3), melhora a contratilidade e perfusão microvascular. Utilizamos esta solução como possível agente indutor de pre-condicionamento ou tolerância. A SSH em doses crescentes de 4, 6 e 8 ml/kg levou a diminuição da mortalidade em camundongos endotoxêmicos o mesmo ocorrendo com outras soluções hiperosmóticas. Analisamos o padrão do perfil de produção de citocinas pró e anti-inflamatórias em períodos de 2 e 4 horas pós SSH e pós LPS. No estudo sistêmico do pré-condicionamento os resultados revelaram uma diminuição da resposta inflamatória causada pelo LPS nas dosagens plasmáticas, o mesmo ocorrendo nos tecidos estudados. Concluímos que o pré-condicionamento com SSH é promissor como um prétratamento na endotoxemia / The tolerance or preconditioning is a host defense strategy able to reduce the infection negative effect in health. Decrease the tissue damage susceptibility caused by the imune response. A fluid imbalance and osmotic pressure intra and extracellular cause the osmotic stress and inflammatory mediators release. The hypertonic saline solution (SSH) has been used in fluid resuscitation, with good results in patients with brain and lung damage, it improves microvascular perfusion and contractility. We used this solution as a possible induct agent of preconditioning or tolerance. The Hypertonic saline solution in increasing doses of 4,6 and 8ml/kg was able to stablish a decrease in endotoxemic mice mortality, the same happened with other hyperosmotic solutions. We analyzed the pattern profile of inflammatory and anti-inflammatory cytokines in a period of two and four hours after SSH. In the systemic study of the precondicioning, the results showed a decrease in the inflammatory response caused by LPS in the plasmatic dosage, the same was observed in the studied tissues. We concluded that the preconditioning with SSH is a promising pre-treatment in endotoxemia

A tolerância ou pré-condicionamento é uma estratégia de defesa do hospedeiro que reduz o impacto negativo da infecção na saúde. Diminui a susceptibilidade a danos teciduais, causados pelos patógenos ou pela resposta imune. Um desbalanço no fluido e pressão osmótica intra e extracelular causa o estresse osmótico e liberação de mediadores inflamatórios. A solução salina hipertônica (SSH) tem sido utilizada na ressuscitação volêmica, mostrando-se benéfica em pacientes com danos cerebrais e pulmonares (3), melhora a contratilidade e perfusão microvascular. Utilizamos esta solução como possível agente indutor de pre-condicionamento ou tolerância. A SSH em doses crescentes de 4, 6 e 8 ml/kg levou a diminuição da mortalidade em camundongos endotoxêmicos o mesmo ocorrendo com outras soluções hiperosmóticas. Analisamos o padrão do perfil de produção de citocinas pró e anti-inflamatórias em períodos de 2 e 4 horas pós SSH e pós LPS. No estudo sistêmico do pré-condicionamento os resultados revelaram uma diminuição da resposta inflamatória causada pelo LPS nas dosagens plasmáticas, o mesmo ocorrendo nos tecidos estudados. Concluímos que o pré-condicionamento com SSH é promissor como um prétratamento na endotoxemia / The tolerance or preconditioning is a host defense strategy able to reduce the infection negative effect in health. Decrease the tissue damage susceptibility caused by the imune response. A fluid imbalance and osmotic pressure intra and extracellular cause the osmotic stress and inflammatory mediators release. The hypertonic saline solution (SSH) has been used in fluid resuscitation, with good results in patients with brain and lung damage, it improves microvascular perfusion and contractility. We used this solution as a possible induct agent of preconditioning or tolerance. The Hypertonic saline solution in increasing doses of 4,6 and 8ml/kg was able to stablish a decrease in endotoxemic mice mortality, the same happened with other hyperosmotic solutions. We analyzed the pattern profile of inflammatory and anti-inflammatory cytokines in a period of two and four hours after SSH. In the systemic study of the precondicioning, the results showed a decrease in the inflammatory response caused by LPS in the plasmatic dosage, the same was observed in the studied tissues. We concluded that the preconditioning with SSH is a promising pre-treatment in endotoxemia

The aim of this thesis is to determine the feasibility of an injectable delivery system based on 5-ethylene ketal ε-caprolactone for localized delivery of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) for treating critical limb ischemia. HGF and VEGF were chosen because of their ability to simultaneously stimulate the proliferation and migration of endothelial cells, to initiate the formation of blood vessels and the recruitment of pericytes to stabilize the blood vessels. Homopolymer of 5-ethylene ketal ε-caprolactone and its copolymer with D,L-Lactide were synthesized by ring opening polymerization using hydrophobic initiator (octan-1-ol) or an hydrophilic initiator (MPEG), and stannous octanoate as a co-initiator/catalyst. The resulting polymers were amorphous and viscous liquids at room temperature. The viscosity, biodegradation rate, and release rate were varied by copolymerizing with D,L-lactide and/or initiating with MPEG or octan-1-ol. In vitro, the polymers degraded with surface erosion characterized by a nearly linear mass loss with time with no significant change in number average molecular weight and glass transition temperature. The ratio of EKC to DLLA in the copolymer remained the same throughout the degradation studies. A similar degradation mechanism was observed in vivo when the copolymer initiated with octan-1-ol was implanted subcutaneously in rats. In vivo, the polymer exhibited a moderate chronic inflammatory response, characterized by the presence of neutrophils, macrophages, fibroblasts and fibrous capsule formation. The inflammatory response decreased with time but was still on going after 18 weeks of subcutaneous implantation. Protein release from the polymer was transported by convection through the hydrated polymer region, at a rate determined by the osmotic pressure generated and the hydraulic conductivity of the polymer. Highly bioactive VEGF and HGF were released in a sustained manner, without burst effect for over 41 days when delivered simultaneously, using the osmotic release mechanism. VEGF was released at the rate of 36 ± 7 ng/day for 41 days, while HGF was released at the rate of 16 ± 2 ng/day for 70 days. Factors that influenced release of proteins were their solubility in the concentrated trehalose solution and hydraulic permeability of the polymer. This delivery system can serve as a potential vehicle for controlled release of VEGF and HGF for treating critical limb ischemia or the controlled release of other proteins for other clinical applications. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2012-05-23 10:18:48.307

Ce travail de thèse porte sur le développement technologique d’outils miniaturiséspour l’exploration de diagrammes de phase de fluides complexes (dispersions colloïdales,solutions de polymères ou tensioactifs, etc). Les outils élaborés permettent dedéterminer des diagrammes de phase par une approche continue à l’aide de la microfluidique.Ils sont basés sur deux types de procédés membranaires différents : la pervaporation(mécanisme d’évaporation de solvant) et la dialyse (mécanisme d’échangesosmotiques). En s’appuyant sur le processus de pervaporation, il a été montré théoriquementet expérimentalement qu’il existe une géométrie pour laquelle le séchageconfiné est homogène. Il est donc possible de construire des diagrammes de phase demélanges à plusieurs composants de l’échelle moléculaire aux colloïdes. Une étudeconsacrée à la compréhension de la complexité du séchage des nanoparticules de silicecommerciales dans un canal microfluidique de type microévaporateur a été miseen place. La cinétique de concentration des particules est décrite jusqu’à la formationd’un état dense ainsi que les divers phénomènes liés au séchage comme l’existenced’une transition de phase dans un système colloïdal, l’apparition de fractures ou la délaminationdu matériau dense. Un nouvel outil microfluidique intégrant une membranede type dialyse offre la possibilité de contrôler les échanges osmotiques à l’échelle dunanolitre. Le protocole de fabrication ainsi que le dimensionnement de la géométriesont présentés. Grâce à cet outil, il est possible de mesurer des pressions osmotiquesde dispersions colloïdales. / This work deals with the technological development of miniaturized tools for theexploration of the phase diagram of complex fluids (colloidal dispersions, solutions ofpolymers or surfactants, etc). The microfluidic tools we elaborated make it possibleto determine phase diagrams of a series of formulations of complex fluids by consumingonly minute amounts of samples. These devices exploit two types of membraneprocesses to concentrate the chemical species : pervaporation (solvent evaporationthrough a dense membrane) and dialysis (osmotic exchanges through a membrane).Concerning the case of pervaporation, we demonstrated theoretically and experimentallythat a specific microfluidic design exists for which concentration fields of chemicalspecies remain spatially homogeneous along the kinetic path followed withinthe phase diagram. Then, it enables to obtain phase diagrams of multi-componentsmixtures from molecular compounds up to colloids, at the nanolitre scale. We reporta study concerning the understanding of the drying process of commercial silica nanoparticlesusing a dedicated microfluidic experiment involving pervaporation. Wepresent the kinetics of the concentration of the particles within the channel up to theformation of a dense colloidal packed bed which invades the channel at a controlledrate. We developed an original microfluidic tool integrating a dialysis membranewhich makes it possible to control osmotic exchanges at the nanoliter scale. We reportthe protocol of microfabrication of this chip and its specific geometry.We presentpreliminary results showing that this tool can be used to measure osmotic pressures ofcolloidal suspensions.

Some researchers have suggested that the weakest link of dental composites is thefiller-matrix bond. However, due to incompleteness of information dealing with this bond and its stability in a humid environment, it was considered desirable to investigate the effect of water on this region, as well as the influence of filler bonding and filler fraction on compressive strength and therm al expansion. Experimental composites containing different filler fractions of either silane-treatedor untreated fillers were made. Compressive strength and coefficient of thermalexpansion were determined using routine methods, while the hydrolytic degradation was investigated by measuring changes in concentrations of elements in the storagewater using atomic absorption spectrophotom etry. Scanning electron microscopicinvestigations were made on fractured samples. The diffusion coefficient of a representative resin system was determined gravimetrically. Seven commercial composites were investigated regarding hydrolyticdegradation. The filler compositions of these composite materials were determined by emission spectroscopy or energy-dispersive x-ray analysis before storage in distilledwater. This water was replaced and analyzed m onthly using plasma spectrophotom etryor atomic absorption spectrophotom etry. After completed water storage the samples were fractured and investigated by useof scanning electron microscopy.From the results of these studies the following conclusions were drawn: 1. The compressive strength of composites changes linearly with increased fillerfraction. Contrary to bonded fillers, composites containing unbonded fillers loststrength with increased filler fraction. 2. Water diffuses through the polymer m atrix and attacks the filler particles. This degradation is most pronounced for untreated fillers containing glass modifying elements such as sodium, barium and strontium. 3. The resin, used as a matrix, influences the speed with which the hydrolyticdegradation of the filler proceeds. 4. The hydrolytic degradation of the filler seemed to be associated w ith micro-crackform ation occurring in the matrix. Of the investigated composites, the micro-filledresin showed the lowest frequency of such crack formations. 5. The coefficient of ther al expansion decreases linearly with increased fillerfraction. Silane treatment did not influence this coefficient. 6. Using a simplified model to predict stresses in a particle filled composite indicatesthat rather high stress levels are induced in the polymer m atrix due to polym erizationshrinkage. This shrinkage induces radial compressive and tangential tensilestresses with respect to the filler surface. Increased filler fraction increases thetangential tensile stresses but reduces the compressive radial stresses. / <p>S. 1-66: sammanfattning, s. 67-168: 6 uppsatser</p> / digitalisering@umu

Alpha 2 agonists are frequently used in equine medicine. This study focused primarily on α2 agonist-induced changes in PCV and TSP. A secondary aim of this study was to investigate the effects of α2 agonist on selected serum biochemical parameters and splenic size in order to identify potential causes for the changes seen in PCV and TSP. Four healthy adult mares were treated in a blinded, randomized, cross-over design with a single dose of xylazine (0.5 mg/kg), romifidine (0.04 mg/kg) or detomidine (0.01 mg/kg) intravenously, or detomidine (0.02 mg/kg) intramuscularly. A 1-week washout period was allowed between treatments. Haematology, TSP, COP, plasma osmolality, glucose, BUN, serum lactate, electrolytes, venous blood pH, ultrasonographic splenic size and degree of clinical sedation were evaluated at different time points post-injection and compared to baseline values. All treatments induced similar clinical sedation in the mares. A significant change over time in PCV and TSP following each treatment was identified, with overall median (range) maximal reductions compared to baseline of 20.9% (12.9 - 27.3%) and 5.8% (3.0 - 10.3%), respectively. Additionally, changes over time were significant for RBC count, BUN, COP and Ca2+, which decreased; and glucose, plasma osmolality, Na+ and splenic size, which increased, when compared to baseline. There was no significant main effect of treatment on PCV, TSP or any other parameters measured except for glucose. This study concluded that changes in PCV, TSP and other biochemical parameters induced by α2 agonists should be taken into consideration when assessing critically ill horses that received these drugs. There was evidence of splenic RBC sequestration as well as fluid shifts; therefore, the results suggest a multifactorial cause for the changes in PCV and TSP. / Dissertation (MSc)--University of Pretoria, 2011. / Companion Animal Clinical Studies / unrestricted

La pomme (Malus Domestica Borkh.), fruit largement répandu dans les pays tempérés est beaucoup consommée. Elle représente une source importante en composés phénoliques. Cette étude s’est intéressée aux polyphénols des tissus du parenchyme. La problématique s’oriente sur les effets de la texture sur la diffusion de ces molécules. L’originalité de l’approche repose sur l’association de la texture, de la pression osmotique et la diffusion des polyphénols. Les méthodes de caractérisations physiques et biochimiques ont permis de mesurer les changements à l´échelle macroscopique et les modifications chimiques qui s’opèrent dans les matrices végétales. Les résultats de l’étude du transfert de matière ont permis de mettre en évidence les différents facteurs pouvant influer sur les valeurs des coefficients de diffusion. La texture, l’épaisseur, la variété du fruit et la pression du milieu diffusant, constituent des facteurs pouvant influencer le transfert de matière. L’étude de l’évolution de composant de la paroi a montré des changements qui s’opèrent au cours de la diffusion. Des analyses microscopiques ont relevé les modifications à l’échelle cellulaire de la diffusion de procyanidines, polyphénols majoritaires et des interactions avec les composants pariétaux. / Apple (Malus domestica Borkh. ) fruit widespread in temperate countries, is much consumed.It represents an important source of phenolic compounds. This study was interestedin polyphenol content of apple tissue parenchyma. The problem concerns effects of texturedegradation on the diffusion of polyphenols molecules. The originality of the approach isbased on the combination of texture, osmotic pressure and polyphenol leaching. Physicaland biochemical methods were used to measure changes at macroscopic scale and chemicalchanges occurring in the parenchymateous tissue . The study of mass transfer highlightedvarious factors that may affect apparent coefficient diffusion. The result showed that thedisintegration of texture , thickness, apple variety and osmotic pressure of leaching mediacan influence mass transfer yield. The study of the Cell walls components showed changesthat occur during leaching process. Light microscopic analysis revealed changes at cellularscale, procyanidins the major polyphenols, leaching phenomena and also interactionswith cell walls matrix.

L'accumulation du soluté à la surface d'une membrane entraîne le phénomène de polarisation de concentration. Ceci est un problème qui affecte tous les systèmes de filtration membranaire car il a pour effet une augmentation de la pression osmotique et par conséquence une réduction substantielle du flux de perméat. Afin de comprendre ce phénomène, nous avons d'abord mené une étude analytique de la filtration tangentielle en solvant pur prenant en compte de l'influence de la pression motrice locale sur le taux de perméation. Lors de cette étude, des solutions analytiques qui augmentent en précision avec l'ordre développé ont ete dérivées. Ensuite nous avons développé une approche analytique qui couple l'hydrodynamique aux transferts de matière pour le cas d'un système de filtration qui opère sous haute pression avec un taux de récupération faible. Dans le but d'intégrer à la fois la dépendance de la pression transmembranaire locale sur le flux de perméat et l'influence de la polarisation de concentration à travers leurs effets osmotiques sur la pression effective, nous avons développé un modèle numérique qui résout l'équation de conservation du soluté couplée aux équations de Navier-Stokes en régime stationnaire dans l'approximation de Prandtl. Nous avons validé cette approche grâce aux solutions analytiques précédemment dérivées. Ensuite, nous avons testé l'influence des principaux paramètres de fonctionnement sur la performance du système et comparé nos résultats avec ceux d'autres modèles numériques. Finalement, la pertinence du modèle a été quantitativement vérifiée grâce à des données tirées des expériences bien documentées en osmose inverse. / Concentration polarization of solute at the membrane surface, because of osmotic pressure effects, is an important phenomenon that can cause substantial reductions in permeation. To understand these phenomena: we first analyze the filtration process for a pure solvent, imposing the influence of the driving pressure on permeation at the membrane. We obtain accurate analytical solutions for the flow fields. We then derive an analytical solution that coupled hydrodynamics to mass transfer for filtration systems working in a situation of High Pressure and Low Recovery. Second, we develop a numerical model that incorporates both physical aspects: the dependency of pressure on permeation and the influence of concentration polarization and their related osmotic effects in the effective pressure at the membrane. For that, the numerical approach solves the solute conservation equation coupled with the Navier-Stokes equations under the steady Prandtl approximation. The solution of the system is performed using a finite difference method of order 2. The validity of this approach is successfully demonstrated with the previous analytical solutions for hydrodynamics, as well as for the coupling with mass transfer. We then test the influence of the main operating parameters (inlet concentration, axial flow rate, operating pressure and membrane permeability) on the performance of the filtration system and compare the results with other numerical models that takes into account concentration polarization phenomenon. Finally, the validity of this model is quantitatively well-proved when using the reported data resulting from reverse osmosis experiments.