Factor VIII, a component of the intrinsic pathway of blood coagulation, has yet to be purified to homogeneity. It appears that, in vivo, the factor VIII coagulant protein is closely associated with one or more other proteins (factor VHI-related antigen and platelet aggregating factor). The material normally isolated from bovine plasma as 'factor VIII' possesses all three activities and is therefore either a mixture or a complex of the various proteins. In the present study, bovine factor VIII:C was purified approximately fivethousand- fold by a combination of ion-exchange chromatography and fractional precipitation. The factor VIII coagulant activity can be separated from the other activities of the 'factor VIII complex' but the procedures involved are not suitable for preparative use as the factor VIII:C which is obtained is unstable. During coagulation, factor VIII:C is required during the activation of factor X. Studies with purified bovine clotting factors indicate that factor IX_a is the enzyme responsible for the cleavage of factor X, in a calcium-dependent reaction which is stimulated by phospholipid. Factor VIII:C further accelerates the rate at which factor X_a is generated. Preliminary investigations of the kinetic parameters of the reaction indicate that the stimulation by factor VIII:C occurs through a marked increase in the V_max of the reaction; factor VIII:C does not affect the K_m for factor X. The coagulant activity of factor VIII is enhanced by exposure to thrombin, but the 'activated' factor VIII:C which is produced is not itself capable of activating factor X in the absence of factor IX_a. Thus, the 'activation' of factor VIII:C, in contrast to the activation of, for example, factors IX and X, does not appear to result in the formation of an enzyme. That is, factor VIII:C is a non-enzymic, high molecular weight cofactor for factor IX_a.

[Truncated abstract] Every year thousands of individuals suffer from thrombotic related complications that in some cases can be fatal and every year millions of women take some form of hormonal contraceptive. In some cases, there is a cause and effect relationship between the two as users of the combined oral contraceptive pill have an increased risk of developing a thrombotic event. Increased circulating levels of oestrogen cause a prothrombotic shift in the coagulation cascade resulting from upregulation of several procoagulant proteins and a decrease of key anticoagulant proteins. One of the most oestrogen sensitive anticoagulants is Protein S (PS), a product of the PROS1 gene. PS acts as a cofactor to activated protein C (aPC) and the PS-aPC complex serves to downregulate clot formation by deactivating the tenase and prothrombinase complexes via proteolytic cleavage of activated factors VIII and V, respectively. As such, low PS levels are associated with an increased risk of developing thrombotic disorders such as pulmonary embolism, stroke or coronary thrombosis and deep vein thrombosis. During pregnancy when oestrogen levels increase, a steady decline in PS is evident in the early weeks of gestation and continues to decrease to below the normal range in the 2nd trimester, remaining there until post-partum. In addition, reduced free and total PS levels are observed in users of the combined oral contraceptive (COC) pill that contains an oestrogen and a progestin. Interestingly, users of 3rd generation COCs have significantly greater reductions of PS than do 2nd generation COC users. The difference between the two forms is the type of progestin, not the oestrogen, which is predominantly ethinyl oestradiol in the majority of commercially available preparations. At present, a mechanism to describe the relationship between oestrogen and/or progesterone associated with the observed in vivo changes in the levels of PS has not been identified. The aim of this thesis was to define the molecular mechanisms involved in the regulation of PS expression by oestrogen and progesterone. In this study, a Combined Single-stranded conformational analysis and Heteroduplex Analysis (CSHA) iv methodology was optimised for screening both PROS1 DNA and mRNA for the detection of mutations. '...' This may explain why users of 3rd generation COCs display a greater reduction in circulating PS levels compared to 2nd generation users. To investigate potential PS interactions with other proteins that could be hormonally regulated, a yeast-2-hybrid (Y-2-H) screen was performed using the PS molecule as a 'bait' against molecules derived from liver and bone marrow cDNA libraries. A clone that contained a portion of another haemostatic protein, Protein Z (PZ) was isolated and confirmed via sequencing. As no full length PZ clones were identified, a second Y-2-H screen was performed once again using the PS molecule as bait and the PZ molecule as the fish. Interaction between the two proteins was shown to be possible via the successful growth of colonies on triple knock out selective media and by positive ß-galactosidase activity.

The City of Winnipeg, MB currently hauls by truck the leachate from the landfill, to be co-treated with the municipal wastewater at a wastewater treatment plant. Pre-treating the leachate with physico-chemical methods would allow for direct discharge to the sewer system, avoiding transportation. The goal of this research is to evaluate the effectiveness of different pre-treatment options as well as their impact on a biological nutrient removal system. In Phase I, the four pre-treatment options evaluated were air stripping, chemical coagulation, electro-coagulation and advanced oxidation with sodium ferrate. Chemical coagulation and air stripping reported the best COD and ammonia removal rates, respectively. Phase II evaluated the effectiveness of the selected pre-treatment methods in the response of a biological treatment system. The pre-treatment was successful in allowing complete nitrification by lowering the influent ammonia concentration. However, if the ratio of leachate to wastewater is low enough; pre-treatment may not be needed as the dilution lowers the impact of the leachate’s higher concentrations.

Thesis (Ph.D. in Clinical Science) -- University of Colorado Denver, 2008. / Typescript. Includes bibliographical references (leaves 136-146). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.

No description available.

No description available.

No description available.

No description available.

No description available.