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This thesis describes a new in vitro slide chamber model that makes it possible to conduct studies of molecular and cellular interactions between whole blood and biomaterials. The model proved to be a suitable tool for detection of cell and platelet binding to a biomaterial surface. It was possible to monitor activation of the blood cascade systems and cells in the fluid phase and detect surface-bound molecules. One finding was that thrombin generation is primarily triggered by FXII on a biomaterial surface since corn trypsin inhibitor, inhibited thrombin generation in blood. Another finding was that thrombin generation was dependent on variety types of blood cells, since thrombin generation was almost negligible in platelet-rich plasma. When various preparations of blood cells were used to reconstitute platelet-rich and platelet-poor plasma, erythrocytes were shown to be the most efficient cell type in triggering thrombin generation. Inhibition of platelet aggregation with aspirin and Ro44-9883 was associated with a decrease in thrombin generation, confirming that platelet activation is necessary for normal coagulation activation. These findings suggest that the central events consist of an initial low-grade generation of thrombin that involves erythrocytes and possibly leukocytes which leads to activation of platelets; and a second platelet-dependent amplification loop that produces most of the thrombin. Titanium exposed to whole blood produced high amounts of thrombin. Stainless steel and PVC, generated lower amounts. This indicates that titanium might be less suitable as a biomaterial in devices that are in direct contact with blood for prolonged time. Considering the superior osteointegrating properties of titanium and titanium's response to blood, a correlation between high thrombogenicity and good osteointegration seems to exist. Compstatin, that binds to complement component C3, effectively inhibited the generation of C3a and sC5b-9 and the binding of C3/C3 fragments to the surface. Our results suggest that a biomaterial is able to activate complement through both the classical and alternative pathways and that the classical pathway alone is able to maintain a substantial bioincompatibility reaction. The results show that complement activation is a prerequisite for activation and binding of PMNs to the surface in the in vitro model.

In patients with unstable coronary artery disease, this study evaluated the degree of inflammation and coagulation activity, relations to myocardial cell damage, prognosis, and influences of randomisation to 72 h infusion with three different doses of inogatran, a direct thrombin inhibitor (n=904), or unfractionated heparin (n=305). Anticoagulant treatment effects were evaluated with aPT time. In inogatran treated patients with aPT times ≥ 44 s (median), the 7-days event rate - death, myocardial infarction or refractory angina – was 11.6 %, compared to 6.6 % with aPT times < 44 s (p=0.01). Higher aPT times was related to improved outcome during heparin treatment. Markers of inflammation, i.e. fibrinogen and C-reactive protein (CRP), and coagulation, i.e. prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complex (TAT), soluble fibrin (SF) and D-dimer were analysed in serial samples (n=320). High fibrinogen, F1+2 and D-dimer levels persisted at 30 days. Patients with myocardial damage, detected by elevated troponin, had higher levels of all markers except TAT. Ischemic events occurred at 30 days in 17 % of patients with high (pre-treatment top tertile) and 8.5 % of patients with lower fibrinogen levels (p=0.03), while high CRP levels only were related to increased mortality. At 30 days, patients with high compared to low pre-treatment levels of TAT or SF had 40 % lower event rate. Patients with early decreased compared to raised F1+2 or TAT levels during treatment had 50 % lower 30-days event rate (p<0.05). Conclusions: The aPT time is an inappropriate indicator of antithrombotic efficacy. The raise in fibrinogen in the acute phase is sustained, and indicates risk of thrombosis and new ischemic events. The pronounced CRP elevation is transient, but associated with increased mortality. Higher coagulation activity may identify patients with a thrombotic condition as the major cause of instability, who are best responders to anticoagulant therapy. However, reactivation of coagulation activity with raised risk of ischemic events is a concern at cessation of treatment.

In 101 patients with ST-elevation myocardial infarction treated with streptokinase the additional effects of lmw-heparin (dalteparin) were investigated. The prognostic value of troponin-T (TnT) was elucidated and the development of myocardial damage was investigated with Positron Emission Tomography (PET). Dalteparin tended to provide a higher rate of TIMI grade 3 flow in the infarct-related artery at 24 h compared to placebo. In patients with signs of early reperfusion there was a higher rate of TIMI grade 3 flow in the dalteparin group compared to placebo. There were significantly fewer patients with ischemic episodes at 6-24 h in the dalteparin compared to placebo group. The increase in coagulation activity was attenuated in the dalteparin group. There was a tendency to more ischemic episodes and lower frequency of TIMI grade 3 flow in patients with persistent elevation of coagulation activity at 18 h. Among deceased patients the coagulation activity was significantly higher than in survivors. The association between elevated TnT on admission and long-term mortality might be explained by longer delay, episodes of chest pain during the last 24 h, less non-invasive signs of reperfusion at 90 minutes, and lower patency in the infarct-related artery at 24 h. Eight patients were investigated with PET at 3h, 24 h and after 3 weeks. PET outlines the infarct region with reduced perfusion and metabolism. The oxidative metabolism in the infarct region at 3 h correlated with the water-Perfusable Tissue Fraction (PTF) and its improvement over time. Dalteparin seems to improve maintenance of coronary patency, which can be explained by attenuation of the increased coagulation activity. Elevated TnT level on admission is associated with a worse outcome, which can partly be explained by less successful fibrinolytic treatment. PET investigations might to be a useful method in future trials evaluating new agents in the treatment of acute myocardial infarction.

The laparoscopic way of performing general surgical procedures was introduced all over the Western world in a few years around 1990. No previous scientific studies of the safety of this new way of performing general surgery had been undertaken. In an animal study, it was shown that carbon dioxide pneumoperitoneum (CO2PP) causes an increase in inferior caval vein (ICV) pressure, although there were no effects on the ICV blood flow. There were gradual increases in systemic, pulmonary and ICV vascular resistance, which remained after exsufflation. These effects on vascular resistance could not be reproduced in a second animal study, presumably due to a different form of anesthesia. In this study, there was only indirect evidence of CO2 PP decreasing urine output. No increase in vasopressin, which is commonly seen during CO2 PP, was found, indicating that vasopressin may play a role in the decreased urine output during CO2 PP but that there must be other contributing factors as well. Only brief effects on the renal arterial blood flow were seen.Renal venous pressure increased to that of the ICV. A literature review indicated that thromboembolic complications do occur after laparoscopic cholecystectomy (LC). The relative frequencies indicated an underreporting of deep vein thrombosis (DVT) in relation to pulmonary embolism (PE). In a clinical study, activation of the coagulation after LC was demonstrated. There were differences between the groups receiving dextran and low molecular weight heparin as prophylaxis. A further clinical study showed the incidence of DVT, as demonstrated by phlebography, to be 2.0 % (95 % confidence interval 0-6.0 %) 7-11 days after LC, even though thromboembolism prophylaxis was given in shorter courses than those scientifically proven to be effective against DVT. D-dimer values increased at the first postoperative day and even further at the time of phlebography, suggesting that the effects of LC on coagulation and/or fibrinolysis may be of longer duration than previously known.

FibMat2.0 is a fibrinogen multilayer developed by AddBIO. Other proteins such as immunoglobulin G (IgG) and human serum albumin (HSA) can also be used to build multilayers with the same technique. The aim of this study of FibMat2.0 was to investigate if the manufacturing of the protein multilayer would induce an immune or haemostatic response in the body. The multilayers of IgG and HSA were also studied. Methods such as null ellipsometry, imaging of coagulation and the cone-and-plate setup were used to study immune reactions, activation of the coagulation cascade, and stability of the multilayers. Small amounts of plasma proteins were adsorbed to fibrinogen multilayers, but complement proteins adsorbed only to the IgG matrix and high molecular weight kininogen (HMWK) adsorbed only to the HSA monolayer. The imaging of coagulation method indicated that the titanium surface and the HSA monolayer activate surface induced coagulation rapidly, whereas fibrinogen and IgG multilayers demonstrated longer coagulation times. Platelets and a few white blood cells were bound to titanium surfaces and fibrinogen multilayers, but not to IgG multilayers or HSA monolayers. A conclusion in this study is that the surface of an implant can be coated with FibMat2.0 without any risks, but more studies are needed to better understand the interactions between the surfaces prepared in the present study and the immune and the haemostatic systems of the human body.

During the past decade clinical islet transplantation has become a viable strategy for curing type 1 diabetes. The limited supply of organs, together with the requirement for islets from multiple donors to achieve insulin independence, has greatly limited the application of this approach. The islets are infused into the liver via the portal vein, and once exposed to the blood, the grafted tissue has been shown to be damaged by the instant blood-mediated inflammatory reaction (IBMIR), which is characterized by coagulation and complement activation as well as leukocyte infiltration into the islets. Islet revascularization is a subsequent critical step for the long-term function of the transplanted graft, which may partially be impeded by the IBMIR. In this thesis, we have explored novel strategies for circumventing the effects of the IBMIR and facilitating islet revascularization. Systemic inhibitors of the IBMIR are typically associated with an increased risk of bleeding. We therefore evaluated alternative strategies for modulating the islets prior to transplantation. We demonstrated, using an adenoviral vector, that a high level of expression and secretion of the anticoagulant hirudin could be induced in human islets. An alternative approach to limiting the IBMIR was developed in which anticoagulant macromolecular heparin complexes were conjugated to the islet surface. This technique proved effective in limiting the IBMIR in both an in vitro blood loop model and an allogeneic porcine model of islet transplantation. An increased adhesion of endothelial cells to the heparin-coated islet surface was demonstrated, as was the capacity of the heparin conjugate to bind the angiogenic factors VEGF and FGF; these results have important implications for the revascularization process. The outcome of the work in this thesis suggests that modulation of the islet surface is an attractive alternative to systemic therapy as a strategy for preventing the IBMIR. Moreover, the same techniques can be employed to induce revascularization and improve the engraftment of the transplanted islets. Ultimately, improved islet viability and engraftment will make islet transplantation a more effective procedure and increase the number of patients whose diabetes can be cured.

Polymer flocculants, traditionally used with primary coagulant to enhance flocculation and sedimentation, are used in the coagulation-/microfiltration process as well assuming they can improve membrane performance similarly. However, there are several uncertainties concerning the use of polymer flocculants in the coagulation-microfiltration process. First, polymer flocculants may not have measurable effect on turbidity removal, because microfiltration membranes can remove significantly smaller particles than those removed by the conventional treatment process. Second, the effect of using polymer flocculants on NOM removal has been controversial. Although a number of studies reported improved NOM removal when polymers were used, others reported no or negative impact of polymers on NOM removal. Third, polymer flocculants are high molecular weight organic compounds. When carried over to membrane residual polymers can potentially foul the membranes. Finally, the use of polymer flocculants will change floc properties (i.e. size, fractal dimension, and stickiness) and subsequently bring uncertain effect on cake layer resistance. Therefore, the role of polymer flocculants in coagulation-microfiltration system needs to be carefully assessed for system optimization. In the reported research, three types of polymer flocculants with different charge and molecular weights were tested for comprehensively evaluating the impact of polymer flocculants on the performance of coagulation-microfiltration of surface water. Operation conditions such as inline filtration, direct filtration, and filtration with sedimentation were included. Two membrane reactors were designed to study the mechanism through which polymer flocculants affect the performance of coagulation-microfiltration systems. The result demonstrated that the use of polymer flocculants provides little to no benefit to turbidity and NOM removal in most cases, but pDADMACs can enhance NOM removal if applied properly; All polymer flocculants significantly increased membrane fouling except for pDADMACs when sedimentation proceeds MF; Polymer flocculants increase deposition/attachment of floc particles on the membrane surface through both adsorption of residual polymer on the membrane surface and polymer molecules on the floc particle surface; Even though polymers form larger and more fractal floc particles, they did not have notable impact on cake layer structure.

Il est probable qu'à terme les émissions de nanoparticules soient réglementées et ce sont donc les concentrations en nombre qui seront considérées. Il convient donc d'adapter les modèles afin de pouvoir simuler correctement les concentrations en nombre, dans les ambiances confinées comme dans l'atmosphère. Un modèle de dynamique des particules capable de suivre avec autant de précision la concentration en nombre que la concentration en masse, avec un temps de calcul optimal, a été développé. La dynamique des particules dépend de divers processus, les plus importants étant la condensation/évaporation, suivie par la nucléation, la coagulation, et les phénomènes de dépôts. Ces processus sont bien connus pour les particules fines et grossières, mais dans le cas des nanoparticules, certains phénomènes additionnels doivent être pris en compte, notamment l'effet Kelvin pour la condensation/ évaporation et les forces de van der Waals pour la coagulation. Le travail a tout d'abord porté sur le processus de condensation/évaporation, qui s'avère être le plus compliqué numériquement. Les particules sont présumées sphériques. L'effet Kelvin est pris en compte car il devient considérable pour les particules de diamètre inférieur à 50 nm. Les schémas numériques utilisés reposent sur une approche sectionnelle : l'échelle granulométrique des particules est discrétisée en sections, caractérisées par un diamètre représentatif. Un algorithme de répartition des particules est utilisé, après condensation/évaporation, afin de conserver les diamètres représentatifs à l'intérieur de leurs sections respectives. Cette redistribution peut se faire en terme de masse ou de nombre. Un des points clé de l'algorithme est de savoir quelle quantité, de la masse ou du nombre, doit être redistribuée. Une approche hybride consistant à répartir la quantité dominante dans la section de taille considérée (le nombre pour les nanoparticules et la masse pour les particules fines et grossières) a été mise en place et a permis d'obtenir une amélioration de la précision du modèle par rapport aux algorithmes existants, pour un large choix de conditions. Le processus de coagulation pour les nanoparticules a aussi été résolu avec une approche sectionnelle. La coagulation est régie par le mouvement brownien des nanoparticules. Pour cette approche, il a été constaté qu'il est plus efficace de calculer le noyau de coagulation en utilisant le diamètre représentatif de la section plutôt que de l'intégrer sur la section entière. Les simulations ont aussi pu montrer que les interactions de van der Waals amplifient fortement le taux de coagulation pour les nanoparticules. La nucléation a été intégrée au modèle nouvellement développé en incorporant un terme source de nanoparticules dans la première section, commençant à un nanomètre. La formulation de ce taux de nucléation correspond à celle de l'acide sulfurique mais le traitement des interactions numériques entre nucléation, coagulation et condensation/évaporation est générique. Différentes stratégies de couplage visant à résoudre séparément ou en même temps les trois processus sont discutées. Afin de pouvoir proposer des recommandations, différentes méthodes numériques de couplage ont été développées puis évaluées par rapport au temps de calcul et à la précision obtenue en terme de concentration massique et numérique

The coagulation/flocculation process is an important part of surface water treatment. It has direct impact on the reliability of plant operations and final water qualities together with cost control. Low water temperature has a significant impact on the operation of drinking water treatment plants, especially on coagulation/flocculation processes.<p> A microscopic image technique has been used to study the coagulation and flocculation process in recent years, but it requires sample handling that disturbs the floc characteristics during measurement. A high resolution photographic technique was applied to evaluate flocculation processes in the present work. With this technique, the images of the flocs were obtained directly while the flocculation process was taking place. In combination with camera control software and particle size analysis software, this procedure provided a convenient means of gathering data to calculate size distribution. Once the size distribution was calculated, the floc growth and floc size change in the aggregation process could be analyzed. Results show that low water temperature had a detrimental impact on aggregation processes. A water temperature of 0 °C resulted in a slow floc growth and small floc size. Although the floc growth rates at 4 °C and 1 °C were less than those at 22 °C, they were higher than at 0 °C. To improve aggregation processes at low water temperature, adding the coagulant aid of anionic copolymer of acrylamide into the water was found to be effective when the temperature was not less than 1 °C. However, it made only a slight impact on aggregation when the temperature approached 0 °C. At water temperatures of 22 °C, 4 °C and 1 °C, the polymer caused the formation of large floc (larger than 0.5 mm2 in projected area). The polymer significantly shortened the required time of flocculation and sedimentation. Three minutes of flocculation and 20 minutes of sedimentation were sufficient for the polymer to achieve good treatment performance, while the flocculation time and sedimentation time had to be 20 and 60 minutes, respectively, without using the polymer. On the other hand, when the temperature was close to 0 °C, the polymer did not cause the formation of the large floc, nor did it shorten the time of flocculation and sedimentation.<p> The experimental results in this research agree with the model for flocculation kinetics given by Argaman and Kaufman (1970). With decreasing water temperature, the aggregation constant (KA) decreased and breakup constant (KB) increased. KA and KB with aluminum sulfate was close to those with ferric sulfate, respectively. <p> In treating the South Saskatchewan River water, an aluminum sulfate or ferric sulfate dosage greater than 50 mg/L resulted in marginal gains in treatment efficiency. Decreasing dosages of aluminum sulfate or ferric sulfate caused lower floc growth rates and smaller floc sizes. Extremely low dosages (5 mg/L or less) resulted in poor floc formation and extremely small sizes.