The endothelium plays an essential role in the regulation of vascular homeostasis and a state of endothelial dysfunction, which develops in the presence of cardiovascular risk factors, may contribute to the development and progression of cardiovascular disease. As such, the measurement of endothelial function, beyond being an experimental tool, may serve as an important tool to complement current risk assessment algorithms in the identification of high-risk patients. Flow-mediated dilation (FMD) is a non-invasive measure of peripheral conduit artery endothelial function that holds great promise. Presently, FMD suffers from methodological heterogeneity and a poor understanding of the various biological components involved in eliciting the dilatory response to a given shear stimulus. We compared both traditional and alternative methods of arterial diameter characterization with regards to their repeatability, nitric oxide-dependency, and their sensitivity in distinguishing between normal and dysfunctional endothelial responses. Our findings emphasize the importance of continuous arterial diameter measurement and suggest that the time to peak FMD is not a useful adjunctive measure of the FMD response. Given that endothelial dysfunction may be of clinical importance, strategies to correct it or prevent it from occurring may be of benefit. The 3-hydroxy-3-methylglutaryl coenzyme A inhibitors are agents that have demonstrated marked cholesterol-independent, endothelial-protective effects. We investigated the ability of rosuvastatin and atorvastatin to protect against endothelial dysfunction associated with ischemia and reperfusion (IR) injury, and chronic nitrate therapy. Using the FMD technique, we demonstrated, for the first time in humans, that acute rosuvastatin administration protects against IR-induced conduit artery endothelial dysfunction. Additionally, we demonstrated that this effect likely occurred by a cyclooxygenase-2-dependent mechanism, which may provide mechanistic insight into the observed cardio-toxicity with cyclooxygenase-2 inhibitors. In contrast, we observed that this endothelial-protective effect was lost upon sustained rosuvastatin administration, which may have important implications regarding the generation of sustained cardioprotective phenotypes. Finally, we demonstrated that atorvastatin co-administration prevented the development of tolerance and endothelial dysfunction associated with continuous transdermal nitroglycerin therapy in humans, likely through an antioxidant mechanism. Future studies are needed in disease patients to determine whether the concept of nitrate tolerance needs reconsideration in the presence of vascular-protective agents.

The endothelium plays an essential role in the regulation of vascular homeostasis and a state of endothelial dysfunction, which develops in the presence of cardiovascular risk factors, may contribute to the development and progression of cardiovascular disease. As such, the measurement of endothelial function, beyond being an experimental tool, may serve as an important tool to complement current risk assessment algorithms in the identification of high-risk patients. Flow-mediated dilation (FMD) is a non-invasive measure of peripheral conduit artery endothelial function that holds great promise. Presently, FMD suffers from methodological heterogeneity and a poor understanding of the various biological components involved in eliciting the dilatory response to a given shear stimulus. We compared both traditional and alternative methods of arterial diameter characterization with regards to their repeatability, nitric oxide-dependency, and their sensitivity in distinguishing between normal and dysfunctional endothelial responses. Our findings emphasize the importance of continuous arterial diameter measurement and suggest that the time to peak FMD is not a useful adjunctive measure of the FMD response. Given that endothelial dysfunction may be of clinical importance, strategies to correct it or prevent it from occurring may be of benefit. The 3-hydroxy-3-methylglutaryl coenzyme A inhibitors are agents that have demonstrated marked cholesterol-independent, endothelial-protective effects. We investigated the ability of rosuvastatin and atorvastatin to protect against endothelial dysfunction associated with ischemia and reperfusion (IR) injury, and chronic nitrate therapy. Using the FMD technique, we demonstrated, for the first time in humans, that acute rosuvastatin administration protects against IR-induced conduit artery endothelial dysfunction. Additionally, we demonstrated that this effect likely occurred by a cyclooxygenase-2-dependent mechanism, which may provide mechanistic insight into the observed cardio-toxicity with cyclooxygenase-2 inhibitors. In contrast, we observed that this endothelial-protective effect was lost upon sustained rosuvastatin administration, which may have important implications regarding the generation of sustained cardioprotective phenotypes. Finally, we demonstrated that atorvastatin co-administration prevented the development of tolerance and endothelial dysfunction associated with continuous transdermal nitroglycerin therapy in humans, likely through an antioxidant mechanism. Future studies are needed in disease patients to determine whether the concept of nitrate tolerance needs reconsideration in the presence of vascular-protective agents.

Chiral a -hydroxy ketones are important structural units in many natural products, biologically active compounds and the hydroxyl group has frequently been used as a reagent directing group, such as for the selective elaboration of aldol products. In this work, enzymatic synthesis of both enantiomers of the a -hydroxy ketones (2-hydroxy indanone, 2-hydroxy tetralone) using Aspergillus niger by selective &amp / #945 / -oxidation of ketones (1-indanone, 1-tetralone) was studied. The &amp / #945 / -oxidation of ketones was carried out by using whole cells of Aspergillus niger in different growth media. A. niger whole cell catalyzed reactions afforded (S)-configurated 2- hydroxy-1-tetralone with %87 e.e. in DMSO at pH 5.0. In addition to this,while (S)-configurated 2-hydroxy-1-indanone with %33 e.e. in pH 8.0 (in DMSO) was synthesized, (R)-configurated-2-hyroxy-1-indanone with %32 e.e. in pH 7.0 ( in DMSO) was synthesized.

The objective of the study presented here was to develop either enzymatic or whole cell mediated green procedures for the syntheses of a-hydroxy ketones. Production of optically active synthons is crucial for the preparation of fine chemicals. Enzymes and whole-cell biocatalysts have proven to be excellent vehicles with their chiral nature for the biotransformations. Under the light of this discussion, firstly benzaldehyde lyase [BAL, (EC 4.1.2.38)] was used in novel C-C bond formation reactions to obtain interesting and biologically important precursors / 2-Hydroxy-1-arylethan-1-ones and functionalized aliphatic acyloin derivatives. All the compounds were obtained with high yields and in the case of aliphatic acyloin derivatives with high enantiomeric excesses (ee&rsquo / s). Another strategy was to use whole cell biocatalysis. A.flavus 200120 was found to be a promising biocatalyst with the ability to catalyze a broad range of reactions / reduction, hydrolysis and deracemization, while another fungus / A. oryzae 5048 was utilized in bioreduction reactions of benzil and its derivatives. Each reaction was investigated, optimized and thus enhanced via medium design. Products were obtained with high yields and ee&rsquo / s. To sum up, in this study novel efficient green procedures were developed to synthesize various ahydroxy ketones with high yield and stereoselectivity. These newly established methods present promising alternatives to classical chemical methodologies.

HudBay Minerals (formerly the Hudson Bay Mining and Smelting Co., Limited) has operated a Zn and Cu processing facility in Flin Flon, MB since the 1930’s. Located in the Boreal Shield, the area surrounding the mine complex has been severely impacted by both natural (forest fires) and the anthropogenic disturbance, which has adversely affected recovery of the local forest ecosystem. Zinc is one of the most prevalent smelter-derived metals in the soils and has been identified as a key factor limiting natural revegetation of the landscape. Because metal toxicity is related more to speciation than to total concentration, Zn speciation in soils from the impacted landscape was characterized using X-ray absorption fine structure, X-ray fluorescence mapping and µ-X-ray absorption near edge structure. Beginning with speciation at a micro-scale and transitioning to bulk speciation was able to determine Zn speciation and link it to two distinct landform characteristics: (1) soils stabilized by metal tolerant grass species—in which secondary adsorption species of Zn (i.e., sorbed to Mn and Si oxides, and as outer-sphere adsorbed Zn) were found to be more abundant; and (2) eroded, sparsely vegetated soils in mid to upper slope positions that were dominated almost entirely by smelter derived Zn minerals, specifically Franklinite (ZnFe2O4). The long-term effect of liming on pH and Zn speciation was examined using field sites limed by a community led organization over a ten year period. Upon liming to a pH of 4 to 4.5, the eroded, sparsely vegetated soils where found to form a Zn-Al-Hydroxy Interlayer Material (HIM) co-precipitate, reducing the phytotoxicity of both Zn and Al and allowed for boreal forest vegetation to recovery quickly in these areas. The grass stabilized soils experienced a steady pH increase, as compared to a sporadic pH increase in the heavily eroded soils, as the buffering capacity was overcome allowing for a transition between multiple adsorption species based upon the point of zero charge of reactive soil elements. Ultimately reaching a near neutral pH after ten years, this allowed for the formation of stable Zn-Al-layered double hydroxide (LDH) soil precipitates and significantly reduced concentrations of plant available Zn.

La 7β-hydroxy-épiandrostérone, stéroïde endogène dérivant de la DHEA, présente des propriétés anti-inflammatoires. En effet, elle module la voie des prostaglandines (PGs) en inhibant la production de la PGE2 pro-inflammatoires et en augmentant la production de la 15-Deoxy-∆12,14-PGJ2 cyto-protectrice in vivo et in vitro. Les faibles doses de 7β-hydroxy-épiandrostérone (1nM, 10nM, 100nM) pour lesquelles ces effets sont observés, suggèrent une liaison à un récepteur spécifique. L'inflammation et la production des PGs jouent un rôle important dans le développement et la prolifération des tumeurs mammaires estrogéno-dépendantes. Le 17β-estradiol (E2), en se fixant sur les récepteurs des estrogènes (REs), induit la production de PGE2 et la prolifération cellulaire dans ces cellules tumorales. De ce fait, notre objectif était de tester les effets de la 7β-hydroxy-épiandrostérone sur la prolifération (comptage avec exclusion au bleu trypan), le cycle cellulaire et l'apoptose (cytométrie de flux) dans les lignées cellulaires de cancer du sein MCF-7 (REα+, REβ+, GPR30+) et MDA-MB-231 (REα-, REβ+, GPR30+) et d'identifier une(des) cible(s) potentielle(s) dans ces cellules (transactivation) et dans des cellules négatives pour les REs nucléaires SKBr3 (GPR30+) (études de prolifération). Cette étude a montré que la 7β-hydroxy-épiandrostérone exerce des effets anti-estrogéniques dans les cellules MCF-7 et MDA-MB-231 associés à une inhibition de la prolifération et un arrêt du cycle cellulaire. Les études de transactivation et de prolifération avec les agonistes spécifiques des REs ont montré une interaction avec le REβ. De plus, les résultats des études de proliférations sur les trois lignées cellulaires suggèrent que la 7β-hydroxy-épiandrostérone pourrait également interagir avec le GPR30. Ces résultats indiquent que ce stéroïde androgène agit comme un anti-estrogène. De plus, c'est la première fois qu'un stéroïde androgène à faible dose montre une action anti-proliférative dans des lignées de cancers du sein. Des études ultérieures restent à réaliser afin de mieux comprendre ces effets observés.

In diabetes hyperglycemia and lack of insulin signaling are key factors in the induction of diabetic sensory neuropathy. The combination of these factors in diabetes may enhance oxidative stress and trigger distal nerve damage in the peripheral nervous system. The link between elevated reactive oxygen species (ROS) levels and nerve degeneration is not clear. We tested the hypothesis that elevation of 4-hydroxy-2-nonenal (4-HNE) induced by oxidative stress in diabetes impairs mitochondrial activity and axonal regeneration in dorsal root ganglion (DRG) neurons. Also, we investigated the association between mitochondrial dysfunction and altered mitochondrial proteome in the axons of streptozotocin–induced diabetic rats. Research design and methods. Cultured adult rat DRG sensory neurons were treated exogenously with 4-HNE, and cell survival, axonal morphology, and level of axon outgrowth assessed. Western blot and fluorescence imaging were used to determine changes in the levels of adducts of 4-HNE and abnormalities in the mitochondria. Proteomic analysis using stable isotope labeling with amino acids in cell culture (SILAC) determined expression of proteins in the mitochondria. Results. 4-HNE impaired axonal regeneration, mitochondrial activity and induced aberrant axonal structures along the axons, which mimicked axon pathology observed in nerve isolated from diabetic rats and replicated aspects of neurodegeneration observed in human diabetic neuropathy. Proteins associated with mitochondrial dysfunction, oxidative phosphorylation and biosynthesis were down regulated in diabetic samples. The axons of diabetic neurons exhibited oxidative stress and depolarized mitochondria. CNTF and resveratrol reversed abnormalities in the mitochondrial membrane potential induced by diabetes and treatment of neurons with 4-HNE. CONCLUSIONS. Elevation of 4-HNE levels in diabetes was associated with impaired mitochondrial function and might be an important link between increased ROS levels and nerve degeneration in diabetic neuropathy. Abnormal mitochondrial function correlated with a down-regulation of mitochondrial proteins, with components of the respiratory chain targeted in lumbar DRG in diabetes. The reduced activity of the respiratory chain was associated with diminished superoxide generation within the mitochondrial matrix and did not contribute to oxidative stress in axons of diabetic neurons.

The research presented in this dissertation focuses on chiral BINOL metal phosphatephosphoric acid catalyzed enantioselective additions of phosphorus and sulfur nucleophiles to imines and epoxides. In chapter 2, we reported a new method to synthesize chiral amino phosphine oxides. The reaction combines N-substituted imines and diphenylphosphine oxide catalyzed by chiral magnesium 9-antryl phosphate. A wide variety of aliphatic and aromatic aldimines substituted by electron neutral benzhydryl or dibenzocycloheptene groups were excellent substrates for the addition reaction. The imines protected with dibenzocycloheptene protecting group provided better enantioselectivity than those protected with benzhydryl group, while both imines gave comparable yields. Also, the substituted diphenylphosphine oxides were excellent nucleophiles obtaining chiral α-amino phosphine oxides in good yields and enantioselectivities. In chapter 3, we reported the first catalytic asymmetric method to prepare enantioenriched N,S-acetals catalyzed TRIP phosphoric acids. The reaction combined N-acyl imines with thiols to generate products in excellent yield and enantioselectivity. Electron-rich and electron-deficient aromatic N-acyl imines were excellent substrate for the addition reaction. A wide range of aliphatic and aromatic thiols obtained the N,S-acetals in excellent yields and enantioselectivities. The TRIP phosphoric acid was found to be an extremely efficient catalyst for the transformation, resulting in asymmetric induction at extremely low catalyst loading. In chapter 4, a highly enantioselective method for desymmetrization of meso-epoxides using thiols catalyzed by substituted BINOL lithium phosphate is reported. This is the first example of epoxide activation using metal phosphate is reported. Various five and six membered aliphatic cyclic meso-epoxides were excellent substrates for the desymmetrization reaction; aromatic acyclic epoxides also reacted with excellent yield and asymmetric induction. Similarly electron rich and electron deficient aromatic thiols obtained the β-hydroxyl sulfides in excellent yields and enantioselectivities.

In diabetes hyperglycemia and lack of insulin signaling are key factors in the induction of diabetic sensory neuropathy. The combination of these factors in diabetes may enhance oxidative stress and trigger distal nerve damage in the peripheral nervous system. The link between elevated reactive oxygen species (ROS) levels and nerve degeneration is not clear. We tested the hypothesis that elevation of 4-hydroxy-2-nonenal (4-HNE) induced by oxidative stress in diabetes impairs mitochondrial activity and axonal regeneration in dorsal root ganglion (DRG) neurons. Also, we investigated the association between mitochondrial dysfunction and altered mitochondrial proteome in the axons of streptozotocin–induced diabetic rats. Research design and methods. Cultured adult rat DRG sensory neurons were treated exogenously with 4-HNE, and cell survival, axonal morphology, and level of axon outgrowth assessed. Western blot and fluorescence imaging were used to determine changes in the levels of adducts of 4-HNE and abnormalities in the mitochondria. Proteomic analysis using stable isotope labeling with amino acids in cell culture (SILAC) determined expression of proteins in the mitochondria. Results. 4-HNE impaired axonal regeneration, mitochondrial activity and induced aberrant axonal structures along the axons, which mimicked axon pathology observed in nerve isolated from diabetic rats and replicated aspects of neurodegeneration observed in human diabetic neuropathy. Proteins associated with mitochondrial dysfunction, oxidative phosphorylation and biosynthesis were down regulated in diabetic samples. The axons of diabetic neurons exhibited oxidative stress and depolarized mitochondria. CNTF and resveratrol reversed abnormalities in the mitochondrial membrane potential induced by diabetes and treatment of neurons with 4-HNE. CONCLUSIONS. Elevation of 4-HNE levels in diabetes was associated with impaired mitochondrial function and might be an important link between increased ROS levels and nerve degeneration in diabetic neuropathy. Abnormal mitochondrial function correlated with a down-regulation of mitochondrial proteins, with components of the respiratory chain targeted in lumbar DRG in diabetes. The reduced activity of the respiratory chain was associated with diminished superoxide generation within the mitochondrial matrix and did not contribute to oxidative stress in axons of diabetic neurons.

Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references.