Motivation In the black population of South Africa, cardiovascular disease (CVD) is rapidly increasing due to urbanisation. Stroke is usually accompanied by a prothrombotic haemostatic profile. Changing lifestyle factors that accompany the urbanisation process could have a negative impact on the haemostatic profile of black South Africans. Elevated levels of pro-coagulant factors, von Willebrand factor (vWF), fibrinogen and fibrin D-dimer have been reported in the black population, which could increase the black population’s susceptibility to CVD. However, low levels of plasminogen activator inhibitor-1 (PAI-1) previously reported in the black population could contribute towards a pro-fibrinolytic state, which may counteract the hypercoagulant state. This may have a beneficial effect on the haemostatic profile of the black population. More investigation into the haemostatic profile of black South Africans is therefore needed to determine if an altered haemostatic profile exists in this group, and if so, to what extent these alterations may relate to cardiovascular dysfunction. This study included markers of both the coagulation (vWF, fibrinogen, fibrin D-dimer) and fibrinolytic (PAI-1, fibrin D-dimer and fibrinolytic potential) systems in an attempt to investigate the haemostatic profile of the black population of South Africa, and for comparison purposes that of the white population as well. The relationship of these markers’ with selected markers of cardiovascular function was also examined to determine if they could possibly contribute to an increase in cardiovascular risk, especially in the black population. Aims The aims of this study were to first compare coagulation and fibrinolysis markers in the black and white populations of South Africa. Furthermore, to determine if associations exist between the selected components of the haemostatic system and markers of cardiovascular function, especially in the black population of South Africa, who tends to be at a higher cardiovascular risk due to altered metabolic and haemostatic profiles. Methodology The Sympathetic activity and Ambulatory Blood Pressure in Africans (SABPA) study was a prospective cohort study that consisted of 409 participants at baseline (2008-2009) that were equally distributed according to both ethnicity (200 black; 209 white) and gender (black, 101 men, 99 women; white, 101 men, 108 women). At follow-up (2011/2012) the cohort totalled 359 participants (170 black, 88 men and 82 women; 189 white, 93 men and 96 women). Data from baseline measurements were used for the first two manuscripts (chapters 2 and 3), while followup data was used for the third manuscript (chapter 4). vWF, fibrinogen, PAI-1, fibrin D-dimer, CLT, serum peroxides, glutathione, glutathione peroxidase and reductase activity were determined, and ambulatory blood pressure and the retinal vessel calibres were measured. The groups were stratified by ethnicity as specified by statistical interaction terms. T-tests and chi-square tests were used to compare means and proportions, respectively. Pearson and partial regression analyses were used to determine correlations between the components of the haemostatic system and cardiovascular function markers. This was followed by multiple linear regression analyses to investigate whether independent associations exist between the variables in both ethnic groups. P-values ≤0.050 were deemed significant. Results and conclusion of each manuscript The first manuscript (chapter 2) compares the haemostatic profiles of the black and white population to determine whether ambulatory blood pressure is related to components of the haemostatic system. The black participants displayed a prothrombotic profile with significantly higher vWF, fibrinogen, PAI-1, fibrin D-dimer and a longer CLT than their white counterparts. Furthermore, partial and multiple linear regression analyses showed a positive association of systolic and diastolic blood pressure with fibrin D-dimer in the black population, while a negative association existed between ambulatory blood pressure and CLT in the white population. These associations suggest that fibrin D-dimer may contribute, at least in part, to the high prevalence of hypertension in the black population. The second manuscript (chapter 3) determined associations between markers of the haemostatic and oxidant-antioxidant systems in the black and white populations. In addition to the prothrombotic profile that exists in the black population, this group also had significantly higher serum peroxides (oxidative stress) and lower glutathione peroxidase activity (antioxidant) levels. Multiple linear regression analyses indicated positive associations between fibrinogen and serum peroxides in both populations. In the white population, an additional positive association was found between serum peroxide and CLT. In the black population, vWF and CLT were negatively associated with GPx activity. The results suggest that there are ethnic-specific relationships between the haemostatic and oxidant-antioxidant systems. The third manuscript (chapter 4) investigated the relationships between the retinal vessel calibres and components of the haemostatic system in the black and white population. The investigation focussed specifically on arteriolar diameters in the lower median, since a narrow arteriolar diameter is known to be associated with elevated blood pressure. In both ethnic groups, a narrower arteriolar calibre was accompanied by narrower venular calibres. Independent positive associations were found between the central retinal vein equivalent (CRVE) and fibrinogen in the black population, as well as vWF and CLT in the white population. In addition, independent negative associations were found between the central retinal artery equivalent and CLT in the black population and with vWF in the white population. The results suggest that haemostatic alterations are linked to early vascular changes that may differ between ethnicities. General conclusion Ethnic-specific relationships between the components of the haemostatic system and measures of cardiovascular function are evident. The prothrombotic profile that is observed in the black population, together with the adverse associations of the haemostatic components with blood pressure, a compromised oxidant-antioxidant profile, and retinal vessel calibres may contribute, at least in part, to the high cardiovascular and cerebrovascular risk evident in this population group. / PhD (Physiology), North-West University, Potchefstroom Campus, 2015

L'aimant organique NIT-2Py a été caractérisé expérimentalement et ses propriétés ont été simulées numériquement à partir de la théorie de la fonctionnelle de la densité. Le magnétisme dans ce matériau provient de la présence d'un électron non apparié sur chaque molécule qui a ainsi un moment magnétique non nul. Ceci a été confirmé par des simulations sur une molécule isolée. Les molécules de NIT-2Py cristallisent dans le groupe d'espace P21/c avec huit molécules par maille élémentaire pour former la structure cristalline Alpha étudiée dans ce document. Le moment effectif de la susceptibilité et l'entropie magnétique totale montre que ce matériau est un système de spins 1/2 avec un spin par molécule. Les mesures de chaleur spécifique ont mis en évidence la présence de deux phases magnétiques ordonnées à basse température qui sont séparées par un plateau en aimantation. Une première phase est observée à des champs magnétiques inférieurs à 2.2 T et a une température de transition de 1.32 K en champ nul. Les mesures de susceptibilité magnétique et d'aimantation ont permis d'établir que cette phase ordonnée est antiferromagnétique. Ceci est confirmé par les simulations numériques. La deuxième phase est induite par le champ magnétique avec une température de transition de 0.53 K à 6 T. L'information disponible sur cette phase est limitée et l'étude du système à l'extérieur des phases ordonnées en donne une meilleure compréhension. Un modèle de spins S=1/2 isolés et de dimères S=0 isolés reproduit bien les mesures d'aimantation et de chaleur spécifique au-dessus de 3 K. L'application d'un champ magnétique réduit l'écart d'énergie entre le singulet et le triplet du dimère jusqu'au croisement qui se produit à 6 T. La phase induite émerge précisément à ce croisement et on spécule l'existence d'un condensat de Bose-Einstein des états triplets. / The organic magnet built from NIT-2Py molecules has been characterized experimentally and its properties have been simulated using density functional theory. In this material, an unpaired electron carrying a magnetic moment on each molecule is responsible for the magnetism. This has been confirmed by numeric simulations on an isolated molecule. NIT-2Py molecules crystallize in space group P21/c with eight molecules per unit cell to form crystalline phase Alpha studied in this document. The effective moment obtained from magnetic susceptibility and the total magnetic entropy show that this material is a spin 1/2 system with one spin per molecule. Specific heat measurements have highlighted the presence of two magnetically ordered phases at low temperature, which are separated by a plateau in magnetization. A first phase is observed at magnetic field lower than 2.2 T and has a transition temperature of 1.32 K in zero field. Magnetic susceptibility and magnetization measurements have established that this ordered phase is antiferromagnetic. This is confirmed by numeric simulations. The second phase is induced by a magnetic field and has a transition temperature of 0.53 K at 6 T. Information concerning the field induced phase is limited and a study of the system above the transition temperatures helps to gain a better understanding. A model of isolated spins S=1/2 and isolated dimers S=0 reproduces nicely the specific heat and magnetization data above 3 K. The application of a magnetic field reduces the energy gap between the singlet and the triplet of the dimer and the crossover between these levels is observed at 6 T. The field induced phase emerges precisely at this crossover suggesting the occurrence of a Bose-Einstein condensation of triplets states.

Une approche synthétique a été développée pour préparer les phtalocyanines dimériques de fer azote ponté substituées par les substituants alkylesulfoniles attracteurs d’électrons. Six nouvelles phtalocyanines avec des petits substituants (méthylesulfonile, éthylesulfonile et hexylesulfonile) et des gros substituants (t-butylesulfonile, adamantylesulfonile et cyclohexylesulfonile) ont été préparées et caractérisées par ionisation électrospray (ESI-MS), UV-vis, FT-IR et RPE. Deux complexes (avec substituants hexylesulfoniles et t-butylesulfoniles) ont été caractérisés par spectroscopie Mössbauer, spectroscopie photoélectronique de rayons X (XPS) et par spectroscopie d’absorption des rayons X (XANES, EXAFS, spectroscopie d’émission Kβ haute résolution). Il a été montré que l’état électronique de fer de ces complexes dépend de la taille de substituants. Les phtalocyanines de fer à l’azote ponté avec les gros substituants (t-butylesulfonile, adamantylesulfonile et cyclohexylesulfonile) sont cationiques (PcFeIVNFeIVPc)+N3-, tandis que les complexes avec les substituants plus gros (t-butylesulfonyles, adamantylesulfonyles et cyclohexylesulfonyles) sont non-chargés, formellement PcFeIIINFeIVPc. Les propriétés catalytiques des six complexes ont été étudiées en utilisant du butyle hydroperoxyde comme oxydant en oxydation de toluène, de p-xylène et des alcools. Ce travail montre l’efficacité des phtalocyanines dimériques de fer azote ponté substituées par les groupements alkylesulfoniles attracteurs d’électrons comme catalyseurs pour oxydation dans les conditions favorables pour les applications industrielles propres / The synthetic approach was developed for the preparation of N-bridged diiron phthalocyanines substituted by different electron-withdrawing alkylsulfonyl substituents. Six novel phthalocyanines bearing small (methylsulfonyl, ethylsulfonyl and hexylsulfonyl) and bulky (t-butylsulfonyl, adamantylsulfonyl and cyclohexylsulfonyl) substituents have been prepared and characterized by electrospray ionization mass spectrometry (ESI-MS), UV-Vis, FT-IR and EPR. Two complexes (with hexylsulfonyl and t-butylsulfonyl substituents) were characterized in addition by Mössbauer techniques, X-ray photoelectron spectroscopy (XPS) and Fe K-edge X-ray absorption spectroscopy (XANES, EXAFS, high resolution Kβ emission spectroscopy). It has been evidenced that the electronic state of iron in these complexes depends on the size of the substituents. While N-bridged diiron phthalocyanines having methylsulfonyl, ethylsulfonyl and hexylsulfonyl substituents are cationic (PcFeIVNFeIVPc)+N3- complexes, N-bridged diiron phthalocyanines with bulkier t-butylsulfonyl, adamantylsulfonyl and cyclohexylsulfonyl substituents are formally neutral PcFeIIINFeIVPc species. The catalytic properties of six N-bridged diiron phthalocyanines have been studied, using tert-butyl hydroperoxide (tBuOOH) as the oxidant in the oxidation of toluene, p-xylene as well as in the oxidation of various alcohols. This thesis demonstrates the efficiency of N-bridged diiron phthalocyanines substituted by electron-withdrawing alkylsulfonyl groups as oxidation catalysts, in conditions required by environmental and industrial preoccupations

A leishmaniose é uma doença negligenciada provocada por parasitas do gênero Leishmania, que ocorre em mais de 90 países no mundo, afetando milhões de pessoas. A doença é tratável, mas ainda não tem cura, e o arsenal terapêutico comumente utilizado é limitado, e consiste do uso de fármacos de alta toxicidade. Sendo assim, a busca por novas terapias tem sido encorajada e o uso de compostos ativos isolados de produtos naturais, como plantas, tem se mostrado eficaz. Para uso futuro destes princípios ativos no tratamento, faz-se necessário o entendimento do seu mecanismo de ação. As ciências \"ômicas\", mais especificamente a metabolômica, que é a análise comparativa dos metabólitos alterados em um sistema biológico após intervenção externa, tem sido bastante aplicada com este objetivo. A abordagem metabolômica é multidisciplinar e as análises são realizadas com auxílio de plataformas analíticas modernas, como as técnicas de separação acopladas a espectrometria de massas (MS). Para tratamento dos dados são utilizadas ferramentas estatísticas avançadas, e as substâncias alteradas são correlacionadas com rotas metabólicas. Neste trabalho, o mecanismo de ação em Leishmania infantum da substância ativa (metildihidrodieugenol B) isolada da planta Nectandra leucantha, foi avaliado por abordagem metabolômica global, com multiplataforma de análise (cromatografia gasosa e líquida em fase reversa hifenadas, GC-MS e RPLC-MS, respectivamente). Otimizações de preparo de amostra, extração, e derivatização para GC-MS, para obter o maior número possível de metabólitos foram realizadas nas amostras em estudo. Promastigotas de L. infantum foram crescidos em meio de cultura e após 72 h foram tratados com metildihidrodieugenol B (na concentração de 58.18 &#181g x mL-1); passadas 48 h de tratamento, a ação enzimática foi interrompida, as células lavadas e congeladas para análise posterior. Metanol:água (1:1) e metanol 100% foram utilizados como solventes extratores para acessar os metabólitos intracelulares nas análises por GC-MS e RPLC-MS, respectivamente. Derivatização com O-metoxiamina em piridina (15 mg x mL-1) à temperatura ambiente por 90 min, seguida de sililação com BSTFA + 1% TMCS por 30 min à 40 ºC foi realizada para tornar voláteis e estáveis os metabólitos para análise por GC-MS. Os resultados de ambas plataformas de análise apontou grandes diferenças entre os grupos de amostras tratadas e não tratadas com a substância ativa, e os metabólitos alterados com significância estatística foram correlacionados com o metabolismo de Leishmania. Diferentes aminoácidos, ácidos graxos, carboidratos, glicerolipídeos e fosfoslipídeos foram encontrados, em sua maioria, diminuídos com o tratamento. Devido a complexidade do metabolismo do parasita e a grande diversidade dos metabólitos alterados, um mecanismo de ação multi-target pode ser atribuído ao dímero de fenilpropanoide. Mudanças no metabolismo da glicólise e gluconeogênese são destacadas, indicando alterações nas fontes de energia da célula. Modificações na composição lipídica da membrana plasmática do parasita também foram observadas, sugerindo variações em sua flexibilidade e fluidez. Os resultados obtidos são preliminares, mas muito importantes para dar o primeiro passo na elucidação da ação desta substância no tratamento da leishmaniose, pleiteando a busca por novas terapias. / Leishmaniasis is a neglected disease caused by Leishmania parasites, which occurs in more than 90 countries worldwide, affecting millions of people. The disease is treatable but not curable, and the commonly used therapeutic arsenal is limited and consists in the use of highly toxic drugs. The search for new therapies has been encouraged and the use of active compounds, isolated from natural products, such as plants, has been proven effective. For future use of these active compounds in the treatment, it is necessary to understand its mechanism of action. \"Omics\" sciences, specifically metabolomics, which is the comparative analysis of altered metabolites in a biological system after external intervention, has been widely applied for this purpose. The metabolomic approach is multidisciplinary and the analyzes are performed using modern analytical platforms, such as separation techniques coupled to mass spectrometry (MS). Data treatment are performed with advanced statistical tools and altered metabolites are correlated with metabolic pathways. In this work, the mechanism of action, in Leishmania infantum, of an active compound (methyldehydrodieugenol B), isolated from Nectandra leucantha plant, was evaluated by global metabolomics approach with multiplatform analysis (gas and reversed phase liquid chromatography, GC-MS and RPLC-MS, respectively). Optimizations of sample preparation, extraction and derivatization for GC-MS to obtain the maximum number of metabolites in the samples under consideration were performed. L. infantum promastigotes were grown in culture medium and after 72 h they were treated with metildihidrodieugenol B (at a concentration of 58.18 µg x mL-1); after 48 h of treatment, enzyme activity was quenched, cells washed and frozen for further analysis. Methanol:water (1:1) and 100% methanol are used as solvent extractor to assess intracellular metabolites for analysis by GC-MS and RPLC-MS, respectively. Derivatization with O-methoxyamine in pyridine (15 mg x mL-1) at room temperature for 90 min, followed by silylation with BSTFA + 1% TMCS for 30 min at 40°C was performed to make volatile and stable metabolites for analysis by GC- MS. The results of both analytical platforms showed significant differences between treated and non-treated samples with the active substance, and altered metabolites with statistical significance were correlated with Leishmania metabolism. Different amino acids, fatty acids, carbohydrates, and glycerolipids phospholipids were found, mostly decreased with treatment. Due to the complexity of the parasite metabolism and the great diversity of altered metabolites, a multi-target mechanism can be assigned to the methyldehydrodieugenol B. Changes in the metabolism of glycolysis and gluconeogenesis are highlighted, indicating changes in the cell energy sources. Changes in the lipid composition of the parasite plasma membrane were also observed, suggesting variations in its flexibility and fluidity. The results are preliminary, but very important to take the first step into elucidation of the action of this substance in the treatment of leishmaniasis, aiming the search for new pharmaceutical therapies.

A leishmaniose é uma doença negligenciada provocada por parasitas do gênero Leishmania, que ocorre em mais de 90 países no mundo, afetando milhões de pessoas. A doença é tratável, mas ainda não tem cura, e o arsenal terapêutico comumente utilizado é limitado, e consiste do uso de fármacos de alta toxicidade. Sendo assim, a busca por novas terapias tem sido encorajada e o uso de compostos ativos isolados de produtos naturais, como plantas, tem se mostrado eficaz. Para uso futuro destes princípios ativos no tratamento, faz-se necessário o entendimento do seu mecanismo de ação. As ciências \"ômicas\", mais especificamente a metabolômica, que é a análise comparativa dos metabólitos alterados em um sistema biológico após intervenção externa, tem sido bastante aplicada com este objetivo. A abordagem metabolômica é multidisciplinar e as análises são realizadas com auxílio de plataformas analíticas modernas, como as técnicas de separação acopladas a espectrometria de massas (MS). Para tratamento dos dados são utilizadas ferramentas estatísticas avançadas, e as substâncias alteradas são correlacionadas com rotas metabólicas. Neste trabalho, o mecanismo de ação em Leishmania infantum da substância ativa (metildihidrodieugenol B) isolada da planta Nectandra leucantha, foi avaliado por abordagem metabolômica global, com multiplataforma de análise (cromatografia gasosa e líquida em fase reversa hifenadas, GC-MS e RPLC-MS, respectivamente). Otimizações de preparo de amostra, extração, e derivatização para GC-MS, para obter o maior número possível de metabólitos foram realizadas nas amostras em estudo. Promastigotas de L. infantum foram crescidos em meio de cultura e após 72 h foram tratados com metildihidrodieugenol B (na concentração de 58.18 &#181g x mL-1); passadas 48 h de tratamento, a ação enzimática foi interrompida, as células lavadas e congeladas para análise posterior. Metanol:água (1:1) e metanol 100% foram utilizados como solventes extratores para acessar os metabólitos intracelulares nas análises por GC-MS e RPLC-MS, respectivamente. Derivatização com O-metoxiamina em piridina (15 mg x mL-1) à temperatura ambiente por 90 min, seguida de sililação com BSTFA + 1% TMCS por 30 min à 40 ºC foi realizada para tornar voláteis e estáveis os metabólitos para análise por GC-MS. Os resultados de ambas plataformas de análise apontou grandes diferenças entre os grupos de amostras tratadas e não tratadas com a substância ativa, e os metabólitos alterados com significância estatística foram correlacionados com o metabolismo de Leishmania. Diferentes aminoácidos, ácidos graxos, carboidratos, glicerolipídeos e fosfoslipídeos foram encontrados, em sua maioria, diminuídos com o tratamento. Devido a complexidade do metabolismo do parasita e a grande diversidade dos metabólitos alterados, um mecanismo de ação multi-target pode ser atribuído ao dímero de fenilpropanoide. Mudanças no metabolismo da glicólise e gluconeogênese são destacadas, indicando alterações nas fontes de energia da célula. Modificações na composição lipídica da membrana plasmática do parasita também foram observadas, sugerindo variações em sua flexibilidade e fluidez. Os resultados obtidos são preliminares, mas muito importantes para dar o primeiro passo na elucidação da ação desta substância no tratamento da leishmaniose, pleiteando a busca por novas terapias. / Leishmaniasis is a neglected disease caused by Leishmania parasites, which occurs in more than 90 countries worldwide, affecting millions of people. The disease is treatable but not curable, and the commonly used therapeutic arsenal is limited and consists in the use of highly toxic drugs. The search for new therapies has been encouraged and the use of active compounds, isolated from natural products, such as plants, has been proven effective. For future use of these active compounds in the treatment, it is necessary to understand its mechanism of action. \"Omics\" sciences, specifically metabolomics, which is the comparative analysis of altered metabolites in a biological system after external intervention, has been widely applied for this purpose. The metabolomic approach is multidisciplinary and the analyzes are performed using modern analytical platforms, such as separation techniques coupled to mass spectrometry (MS). Data treatment are performed with advanced statistical tools and altered metabolites are correlated with metabolic pathways. In this work, the mechanism of action, in Leishmania infantum, of an active compound (methyldehydrodieugenol B), isolated from Nectandra leucantha plant, was evaluated by global metabolomics approach with multiplatform analysis (gas and reversed phase liquid chromatography, GC-MS and RPLC-MS, respectively). Optimizations of sample preparation, extraction and derivatization for GC-MS to obtain the maximum number of metabolites in the samples under consideration were performed. L. infantum promastigotes were grown in culture medium and after 72 h they were treated with metildihidrodieugenol B (at a concentration of 58.18 µg x mL-1); after 48 h of treatment, enzyme activity was quenched, cells washed and frozen for further analysis. Methanol:water (1:1) and 100% methanol are used as solvent extractor to assess intracellular metabolites for analysis by GC-MS and RPLC-MS, respectively. Derivatization with O-methoxyamine in pyridine (15 mg x mL-1) at room temperature for 90 min, followed by silylation with BSTFA + 1% TMCS for 30 min at 40°C was performed to make volatile and stable metabolites for analysis by GC- MS. The results of both analytical platforms showed significant differences between treated and non-treated samples with the active substance, and altered metabolites with statistical significance were correlated with Leishmania metabolism. Different amino acids, fatty acids, carbohydrates, and glycerolipids phospholipids were found, mostly decreased with treatment. Due to the complexity of the parasite metabolism and the great diversity of altered metabolites, a multi-target mechanism can be assigned to the methyldehydrodieugenol B. Changes in the metabolism of glycolysis and gluconeogenesis are highlighted, indicating changes in the cell energy sources. Changes in the lipid composition of the parasite plasma membrane were also observed, suggesting variations in its flexibility and fluidity. The results are preliminary, but very important to take the first step into elucidation of the action of this substance in the treatment of leishmaniasis, aiming the search for new pharmaceutical therapies.

Ces travaux de thèse traitent de l’utilisation d’une molécule polycyclique, l’acide abiétique, issu de la colophane, et de dérivés phénoliques potentiellement dérivés de la lignine, pour la synthèse de polymères rigides bio-sourcés. Dans les deux cas, des monomères symétriques et difonctionnels sont élaborés par réaction de dimérisation des précurseurs bio-sourcés puis testés en polymérisation. D’une part, les dimères de l’acide abiétique obtenus par un mécanisme cationique possèdent des structures mal définies qui compliquent leur polymérisation. Ces dimères ont alors été estérifiés avec de l’undécénol afin d’obtenir un composé bis-insaturé qui est ensuite polymérisé par ADMET. D’autre part, un procédé de dimérisation de molécules phénoliques, potentiellement issues de la lignine, a été développé par voie enzymatique utilisant une laccase. L’avantage majeur de ce procédé ‘vert’ réside dans la séparation très simple entre le monomère, soluble, et son dimère, insoluble. Ces dimères ont ensuite été modifiés chimiquement afin de constituer une bio-plateforme de composés biphényles fonctionnels. Ces composés ont été utilisés pour la synthèse de polyesters, polyamides et résines époxy qui présentent des propriétés thermiques et thermomécaniques remarquables. / The aim of this thesis is to investigate new biobased rigid synthons for the synthesis of polymers with high thermomechanical properties. A polycyclic biobased molecule, i.e resinic acids, and phenolic compounds potentially derived from lignin, such as vanillin were selected. Both classes of substrates were dimerized in order to get difunctional symmetric synthons. On the one hand, abietic acid dimers synthesized via a cationic mechanism presented an ill-defined structure. To avoid reactivity issues, dimers with reactive terminal double bonds were successfully synthesized by esterification of abietic acid dimers with undecenol and polymerized by ADMET methodology. On the other hand, we developed a “green” process to dimerize phenolic compounds derived from lignin in large quantity and high yield via enzymatic catalysis using a laccase. The main advantage of this method is that the phenolic monomer is soluble in the reaction medium while the dimer precipitates. After chemical modifications of the dimers, we built a functional bio-platform of biphenyl derivatives. The latter were then used for the synthesis of polyesters, polyamides and epoxy resins which exhibited remarkable thermal and thermomechanical properties.

<p>A number of active site mutants of human Alpha class glutathione transferase A1-1 (hGST A1-1) were made and characterized to determine the structural determinants for alkenal activity. The choice of mutations was based on primary structure alignments of hGST A1-1 and the Alpha class enzyme with the highest alkenal activity, hGST A4-4, from three different species and crystal structure comparisons between the human enzymes. The result was an enzyme with a 3000-fold change in substrate specificity for nonenal over 1-chloro-2,4-dinitrobenzene (CDNB).</p><p>The C-terminus of the Alpha class enzymes is an α-helix that folds over the active site upon substrate binding. The rate-determining step is product release, which is influenced by the movements of the C-terminus, thereby opening the active site. Phenylalanine 220, near the end of the C-terminus, forms an aromatic cluster with tyrosine 9 and phenylalanine 10, positioning the β-carbon of the cysteinyl moiety of glutathione. The effects of phenylalanine 220 mutations on the mobility of the C-terminus were studied by the viscosity dependence of k_cat and k_cat/K_m with glutathione and CDNB as the varied substrates. </p><p>The compatibility of slightly different subunit interfaces within the Alpha class has been studied by heterodimerization between monomers from hGST A1-1 and hGST A4-4. The heterodimer was temperature sensitive, and rehybridized into homodimers at 40 ˚C. The heterodimers did not show strictly additive activities with alkenals and CDNB. This result combined with further studies indicates that there are factors at the subunit interface influencing the catalytic properties of hGST A1-1.</p>

<p>Acute thrombo-embolic occlusion of the superior mesenteric artery (SMA) with intestinal infarction is a lethal disease, difficult to diagnose in time, with unknown incidence and cause-specific mortality. The aim of this thesis was to characterize the disease and to develop diagnostic methods. </p><p>Two laboratory studies were conducted on patients with suspected acute SMA occlusion. A pilot-study showed that the fibrinolytic marker D-dimer was elevated in six patients with the disease. In the subsequent study including 101 patients, D-dimer was the only elevated coagulation marker in nine patients with the disease. In a prospective study 24 patients (median age 84 years) were identified, of whom four were diagnosed at autopsy, despite an autopsy-rate of 10%. One-fourth were initially nursed in non-surgical wards. Length of the intestinal infarction was a predictor for death. An analysis of patients from the three studies showed that D-Dimer was elevated in all 16 tested patients with the disease.</p><p>Sixty patients with acute SMA occlusion underwent intestinal revascularisation and were registered in the Swedish Vascular Registry (SWEDVASC). One-year survival-rate was 40%. Previous vascular surgery was a negative risk-factor.</p><p>A population-based study was conducted in Malmö, based on an autopsy-rate of 87%. Among 270 patients with the disease, 2/3 were diagnosed only at autopsy and 1/2 were managed in non-surgical wards. The incidence was 8.6 per 100000 person years. The age-standardized incidence increased exponentially without gender differences. The diagnosis was the cause of death in 1.2% among octogenarians and beyond. Thrombotic occlusions were located proximally within the SMA and associated with extensive intestinal infarctions. Synchronous embolism, often multiple, occurred in 2/3 of the patients with embolic occlusions.</p><p>Conclusions: A normal D-dimer at presentation most likely excludes the diagnosis. Acute SMA occlusion was more frequent than previously estimated from clinical series. The patients were often nursed in non-surgical wards.</p>

A number of active site mutants of human Alpha class glutathione transferase A1-1 (hGST A1-1) were made and characterized to determine the structural determinants for alkenal activity. The choice of mutations was based on primary structure alignments of hGST A1-1 and the Alpha class enzyme with the highest alkenal activity, hGST A4-4, from three different species and crystal structure comparisons between the human enzymes. The result was an enzyme with a 3000-fold change in substrate specificity for nonenal over 1-chloro-2,4-dinitrobenzene (CDNB). The C-terminus of the Alpha class enzymes is an α-helix that folds over the active site upon substrate binding. The rate-determining step is product release, which is influenced by the movements of the C-terminus, thereby opening the active site. Phenylalanine 220, near the end of the C-terminus, forms an aromatic cluster with tyrosine 9 and phenylalanine 10, positioning the β-carbon of the cysteinyl moiety of glutathione. The effects of phenylalanine 220 mutations on the mobility of the C-terminus were studied by the viscosity dependence of kcat and kcat/Km with glutathione and CDNB as the varied substrates. The compatibility of slightly different subunit interfaces within the Alpha class has been studied by heterodimerization between monomers from hGST A1-1 and hGST A4-4. The heterodimer was temperature sensitive, and rehybridized into homodimers at 40 ˚C. The heterodimers did not show strictly additive activities with alkenals and CDNB. This result combined with further studies indicates that there are factors at the subunit interface influencing the catalytic properties of hGST A1-1.

Acute thrombo-embolic occlusion of the superior mesenteric artery (SMA) with intestinal infarction is a lethal disease, difficult to diagnose in time, with unknown incidence and cause-specific mortality. The aim of this thesis was to characterize the disease and to develop diagnostic methods. Two laboratory studies were conducted on patients with suspected acute SMA occlusion. A pilot-study showed that the fibrinolytic marker D-dimer was elevated in six patients with the disease. In the subsequent study including 101 patients, D-dimer was the only elevated coagulation marker in nine patients with the disease. In a prospective study 24 patients (median age 84 years) were identified, of whom four were diagnosed at autopsy, despite an autopsy-rate of 10%. One-fourth were initially nursed in non-surgical wards. Length of the intestinal infarction was a predictor for death. An analysis of patients from the three studies showed that D-Dimer was elevated in all 16 tested patients with the disease. Sixty patients with acute SMA occlusion underwent intestinal revascularisation and were registered in the Swedish Vascular Registry (SWEDVASC). One-year survival-rate was 40%. Previous vascular surgery was a negative risk-factor. A population-based study was conducted in Malmö, based on an autopsy-rate of 87%. Among 270 patients with the disease, 2/3 were diagnosed only at autopsy and 1/2 were managed in non-surgical wards. The incidence was 8.6 per 100000 person years. The age-standardized incidence increased exponentially without gender differences. The diagnosis was the cause of death in 1.2% among octogenarians and beyond. Thrombotic occlusions were located proximally within the SMA and associated with extensive intestinal infarctions. Synchronous embolism, often multiple, occurred in 2/3 of the patients with embolic occlusions. Conclusions: A normal D-dimer at presentation most likely excludes the diagnosis. Acute SMA occlusion was more frequent than previously estimated from clinical series. The patients were often nursed in non-surgical wards.