Diagnosis of acute pancreatitis (AP) is erroneous in up to one third of patients when based on clinical criteria and elevated serum amylase values. Furthermore, according to autopsy reports fatal pancreatitis remains clinically undiagnosed in 22 to 86 % of hospitalised patients. Consequently, search for better methods for the diagnosis of AP seems not only justified but urgent. The pancreas secretes an nonspecific lipase, the carboxylic ester hydrolase (CEH) with molecular properties different from other pancreatic secretory enzymes. These differences may imply that sites and rates of clearances from blood of pancreatic enzymes differ. Except for the pancreas this enzyme is secreted from the lactating mammary gland with milk. A sensitive and reproducible sandwich-ELISA for quantitative determination of CEH was developed. When establishing referent values it was noted that in individuals aged 20 to 65 years serum concentrations of CEH did not depend on age, gender, the time of the day or duration from food intake to blood sampling, or use of nicotine. The mammary gland did not contribute significantly to basal serum levels of CEH; enzyme levels in lactating women or women with mammary tumours were identical to those of the reference population. Seventy percent of patients with the diagnosis AP, based on elevated serum amylase levels and abdominal pain, had elevated CEH values. Among the patients with elevated amylase alone a probable cause of pancreatitis was lacking in the majority of patients. Contrastingly, a likely cause of AP could be identified in all patients presenting with abdominal pain and elevated CEH levels alone. These findings suggested that an elevated CEH level indicated AP more reliably than an elevated amylase level. In patients with AP diagnosed by contrast enhanced computed tomography (CECT) alone, or combined with histopathological diagnosis, serum CEH levels were elevated on admission in all but one patient, and in all within the next 24 h. Furthermore, in patients with severe pancreatitis CEH levels remained at a raised level from the second to at least the 10:th day following admission, whereas a significant decrease was noted in patients with mild pancreatitis. In contrast, serum amylase values were higher in patients with mild pancreatitis during the observation period than in those with severe pancreatitis. CEH levels were higher in patients with three or more Ranson signs than in those with less than three signs from the first day after admission. CEH levels were within referent range in 164 patients without known pancreatic disease admitted due to abdominal emergency conditions, or due to planned surgery for chronic extrapancreatic gastrointestinal diseases, and 16 patients having CECT without pathological findings in the pancreas. This suggests that AP can be excluded with very high degree of probability in presence of non-elevated CEH levels. A sandwich ELISA for determination of Guinea pig CEH and a model for graded pancreatitis in the same species were developed. CEH levels showed proportional to severity of inflammation, thus confirming previous clinical observations. CEH levels in bile were proportional to inflammation, while it was absent in urine. Amylase levels in urine were identical regardless of severity of inflammation, but low in bile. These results suggested differences in sites and rates of clearance between the two enzymes. Seemingly elevated CEH levels allowed identification of clinically significant pancreatitis following ERCP, which amylase levels did not. The presented studies have shown that quantitative determination in serum of CEH by the described method is a more reliable test for the diagnosis of AP than determination of amylase activity. The differences between CEH and amylase are, at least partly, due to differences in molecular properties determining rates and routes of clearances of the two enzymes from serum. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu.se

published_or_final_version / abstract / toc / Chemistry / Master / Master of Philosophy

No description available.

Thesis (Ph.D.); Submitted to Department of Chemical Engineering, Colorado School of Mines, Golden, CO (US); 1 Sep 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "LA-14178-T" R.L. Ames. 09/01/2004. Report is also available in paper and microfiche from NTIS.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2003. / Vita. Bibliography: 148-166.

Biocatalysis is a field rapidly expanding to meet a demand for green and sustainable chemical processes. As the use of enzymes for synthetic chemistry becomes more common, the construction of multistep enzyme reactions is likely to become more prominent providing excellent cost and productivity benefits. However, the design and optimisation of multistep reactions can be challenging. An enzyme toolbox of well-characterised enzyme parts is critical for the design of novel multistep reactions. Furthermore, while whole-cell biocatalysis offers an excellent platform for multistep reactions, we are limited to the use of mesophilic host organisms such as Escherichia coli. The development of a thermophilic host organism would offer a powerful tool allowing whole-cell biocatalysis at elevated temperatures. This study aimed to investigate the construction of a multistep enzyme reaction from well-characterised enzyme parts, consisting of an esterase, a carboxylic acid reductase and an alcohol dehydrogenase. A novel thermostable esterase Af-Est2 was characterised both biochemically and structurally. The enzyme shows exceptional stability making it attractive for industrial biocatalysis, and features what is likely a structural or regulatory CoA molecule tightly bound near the active site. Five carboxylic acid reductases (CARs) taken from across the known CAR family were thoroughly characterised. Kinetic analysis of these enzymes with various substrates shows they have a broad but similar substrate specificity and that electron rich acids are favoured. The characterisation of these CARs seeks to provide specifications for their use as a biocatalyst. The use of isolated enzymes was investigated as an alternative to whole-cell biocatalysis for the multistep reaction. Additional enzymes for the regeneration of cofactors and removal of by-products were included, resulting in a seven enzyme reaction. Using characterised enzyme parts, a mechanistic mathematical model was constructed to aid in the understanding and optimisation of the reaction, demonstrating the power of this approach. Thermus thermophilus was identified as a promising candidate for use as a thermophilic host organism for whole-cell biocatalysis. Synthetic biology parts including a BioBricks vector, custom ribosome binding sites and characterised promoters were developed for this purpose. The expression of enzymes to complete the multistep enzyme reaction in T. thermophilus was successful, but native T. thermophilus enzymes prevented the biotransformation from being completed. In summary, this work makes a number of contributions to the enzyme toolbox of well-characterised enzymes, and investigates their combination into a multistep enzyme reaction both in vitro and in vivo using a novel thermophilic host organism.

xv, 116 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Aqueous solutes next to hydrophobic interfaces arc prevalent in a multitude of chemical and biological systems throughout the world. Their presence ranges from environmental processes such as soil and water remediation to biological processes such as ion transport, membrane formation, and enzyme activity. In these and other examples, the interface is an integral part of the system. Understanding these chemically complex systems requires that a molecular level picture be built as a starting basis. In this dissertation, vibrational sum-frequency spectroscopy (VSFS), a surface selective non-linear optical technique, is used to obtain a fundamental understanding of the interfacial properties of carboxylic acid based surfactants and polymers at the oil-water interface. Interfacial studies of the solvating environment around a carboxylate headgroup surfactant are presented first. By utilizing different VSFS polarization schemes, the carboxylate vibrational stretching region was used to monitor the headgroup environment. Results showed the oil-water interface provides a unique environment for adsorption and structuring, and distinct differences exist from the air-water and solid-water interface. With the information gained in the first study, the binding of metal ions to carboxylate headgroups is investigated using VSFS. Mg 2+ , Ca 2+ , Mn 2+ , Ni 2+ , Cu 2+ , and Zn 2+ were used to perturb the headgroup vibrations to further our understanding of the types of interactions and the binding strength between the ion and headgroup. The results show each ion to have a different interaction characteristics with the strongest being bi-dentate in nature and the weakest having ionic character. The final work presented involves moving VSFS studies towards macromolccular assemblies at the oil-water interface to model inherently complex biomolecular systems. These studies present adsorption structure and dynamics of poly(acrylic-acid) as a function of pH, molecular weight, concentration, and the presence of mono and divalent salts. Poly(acrylic-acid) was found to have ordered adsorption characteristics that were highly dependent on the pH and the presence of aqueous salts. This dissertation includes unpublished co-authored materials. / Committee in charge: Thomas Dyke, Chairperson, Chemistry; Geraldine Richmond, Advisor, Chemistry; John Hardwick, Member, Chemistry; Jeffrey Cina, Member, Chemistry; 1. Andrew Berglund, Member, Chemistry; John Conery, Outside Member, Computer & Information Science

abstract: Carboxylic acids are an abundant and reactive species present throughout our solar system. The reactions of carboxylic acids can shape the organic abundances within oil field brines, carbonaceous chondrites, and different ranks of coal. I have performed hydrothermal experiments with model aromatic carboxylic acids in the presences of different oxide minerals to investigate the reactions available to carboxylic acids in the presence of mineral surfaces. By performing experiments containing one organic compound and one mineral surface, I can begin to unravel the different reactions that can occur in the presence of different minerals. I performed experiments with phenylacetic acid (PAA), hydrocinnamic acid (HCA) and benzoic acid (BA) in the presence of spinel (MgAl2O4), magnetite (Fe3O4), hematite (Fe2O3), and corundum (Al2O3). The focus of this work was metal oxide minerals, with and without transition metal atoms, and with different crystal structures. I found that all four oxide minerals facilitated ketonic decarboxylation reactions of carboxylic acids to form ketone structures. The two minerals containing transition metals (magnetite and hematite) also opened a reaction path involving electrochemical oxidation of one carboxylic acid, PAA, to the shorter chain version of a second carboxylic acid, BA, in experiments starting with PAA. Fundamental studies like these can help to shape our knowledge of the breadth of organic reactions that are possible in geologic systems and the mechanisms of those reactions. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2017

Orientador: Nelson Ramos Stradiotto / Banca: Hideko Yamanaka / Banca: Rodrigo Alejandro Abarza Muñoz / Resumo: O etanol é um importante componente da matriz energética brasileira, sendo produz ido a partir da cana - de - açúcar. Nesse processo de produção, é produzida vinhaça como subproduto, a qual pa ra cada 1 L de etanol gera - se de 12 L a 18 L . A vinhaça é constituída principalmente de sais de potássio, cálcio e magnésio e compostos orgânicos . Dentre estes, os ácidos carboxílicos tornam - se importantes por estarem presentes em concentrações significativas na vinhaça de cana - de - açúcar e por apresentarem expressiva importância industrial. Sendo assim, n esse trabalho foi dese nvolvi do um detector eletroquímico baseado em eletrodo s de diamante dopado com boro quimicamente modificado s com nanopartículas de níquel ( NiNPs - BDD ) e de cobre ( CuNPs - BDD ) para determinação dos ácidos lático, málico e tartárico em vinhaça de cana - de - açúca r utilizando a técnica de cromatografia líquida de alta eficiência (CLAE) de troca iônica. Imagens de microscopia eletrônica de varredura e espectros de raios X por dispersão em energia, em conjunto com os experimentos eletroquímicos, mostraram que o s elet rodo s de BDD fo ram efetivamente modificado s com nanopartículas de óxido - hidróxido de níquel e óxido de cobre com diâmetro s médio s de 89 nm e 91 nm, respectivamente . Os estudos voltamétricos mostraram que as oxidações dos ácidos lático, málico e tartárico, em meio básico, se dão em potenciais em torno de 0,50 V ( vs. Ag/AgCl) e 0,73 V ( vs. Ag/AgCl), nos eletrodos NiNPs - BDD e CuNPs - BDD, respectivamente, e são mediadas pelas espécies Ni 3+ e Cu 3 + . O eletrodo de NiNPs - BDD foi utilizado em CL AE com detecção amperométric a pulsada. A coluna de troca aniônica CarboPac PA 1 foi utilizada para separação dos ácidos carboxílicos em vinhaça . E mpreg ou - se como fase móvel água deionizada e 0,10 mol L - 1 de NaOH em 0,25 mol L - 1... / Abstract: Ethanol is an important component of the Brazilian energy ma trix, being produced from sugar cane. In this producing procedure, vinasse is produced as by - product, which for every 1 L of ethanol is generated from 12 L to 18 L . The vinasse is basically composed by salts of p otassium, calcium and magnesium and organic compounds . Among these, carboxylic acids are important because they are present in significant concentrations in the sugar cane vinasse and show sig nificant industrial importance. Thus, in this work it was developed an electrochemical detector based on boron - doped diamond electrodes chemically modified with nickel nanoparticles (NiNPs - BDD) and copper nanoparticles (CuNPs - BDD) for the determination of lactic ac id, malic acid and tartaric acid in vinasse from sugarcane using high - performance liquid chromatography (HPLC) by ion exchange. Image s of scanning electron microscopy and spectra of e nergy - dispersive X - ray in conjuction with electrochemical experiments showed the electrodes of BDD were effectively modified with nickel oxide - hydroxide nanoparticles and copper oxide nanoparticles with diameter s of 89 nm and 91 nm, respectively . The voltammetric studies showed the oxidation s of lactic acid, malic acid and tartaric acid, in basic medium, tooke place at potential s around 0.50 V ( vs. Ag/AgCl) and 0.73 V ( vs. Ag / AgCl) at NiNPs - BDD and CuNPs - BDD electrodes, respectively, and they are mediated by Ni 3 + and Cu 3 + species. NiNPs - BDD electrode was used in HPLC with pulsed amperometr ic detection. The anion exchange column Carbo Pac PA1 was used for separation of carboxylic acids in vinasse. It w as employed as mobile phase deion ized water and 0.10 mol L - 1 NaOH in 0.25 mol L - 1 CH3COONa und er flow of 1.0 m L min - 1 . The detect ion potential was 0.48 V vs . Pd. The NiNPs - BDD electrode showed good stability under chromatographic conditions... / Mestre

La formation argileuse du Callovo-Oxfordien (COx) est étudiée comme possible roche-hôte d’un stockage profond de déchets radioactifs (projet Cigéo). En effet, en plus d’être très faiblement perméable, elle présente une forte teneur en minéraux argileux, capables de retenir les radionucléides sous forme cationique et d’en retarder ainsi fortement leur transport. Néanmoins, certains colis de déchets sont susceptibles de relarguer d’importante quantité de molécules organiques, capables de complexer ces radionucléides et d’augmenter leur mobilité. Aussi, l’objectif de ce travail a été de mieux comprendre le comportement diffusif de plusieurs molécules organiques d’intérêt vis à vis de cette roche argileuse, en investiguant dans un premier temps leur affinité avec la roche hôte. La rétention de molécules organiques sous forme anionique (acétate, phtalate, adipate, benzoate, citrate) a été quantifiée sur la roche argileuse du COx dispersée à l’aide d’expériences d’adsorption/désorption en batch. Des expériences sur roche décarbonatée et fraction de faible granulométrie ont également été réalisées afin de mettre en évidence les phases de la roche et les fonctions chimiques responsables de la rétention. L’intensité de la rétention, Rd, a pu être corrélée avec le moment dipolaire, µ(Orga.), pour fournir une estimation qualitative de la rétention de molécules organiques polaires hydrophiles. Ainsi, le phtalate, légèrement polaire, présente une rétention réversible (Rd ~1,6 L.kg 1), majoritairement sur les phases argileuses. Le citrate, très polaire et fortement adsorbé (Rd ~ 40 L.kg-1), présente une hystérèse de désorption persistante et une affinité avec différentes phases de la roche (minéraux argileux et oxydes minoritaires). Enfin, l’acétate, l’adipate et le benzoate, peu polaires, présentent une affinité moindre avec la roche (Rd < 0,2 L.kg-1). Le comportement diffusif sur roche compacte de ces anions organiques a alors été étudié. Les valeurs de coefficient de diffusion effectif, De, et facteur de retard ont été quantifiées. La faible diffusivité, [De/D0]ANIONS ORGANIQUES ~ 0,1 à 0,25 × [De/D0]EAU, indique un effet d’exclusion anionique, de même intensité que celui observé pour les anions inorganiques. De plus, les coefficients d’adsorption, Kd, estimés à partir des retards à la diffusion sont environ 2 à 5 fois inférieurs aux coefficients de distribution Rd mesurés sur roche dispersée. Cette différence de comportement n’a pas pu être imputée, ni à des effets de cinétique, ni à des effets de porosité accessible aux anions. Quoiqu’il en soit, les espèces complexantes présentent un retard significatif à la diffusion (Kd > 0,2 L.kg-1), ce qui conforte les capacités de confinement de la roche vis-à-vis de ces espèces. / The Callovo-Oxfordian mudstone (COx) is studied as a possible host rock for a deep disposal of radioactive waste (Cigéo project). Indeed, besides being very weakly permeable, it presents a high content of clayey minerals, capable of retaining radionuclides under cationic form and to delay strongly their transport. Nevertheless, some waste packages may release a significant amount of organic molecules, capable of complexing these radionuclides and drastically increase their mobility. So, the objective of this work was to better understand the diffusive behavior of several organic molecules of interest in this mudstone, by investigating at first their affinity with the host rock. The retention of organic molecules under anionic form (acetate, phthalate, adipate, benzoate, and citrate) was quantified on to the dispersed COx mudstone using adsorption/desorption batch experiments. Experiments on decarbonated rock and clay fraction only (< 2µm) were also performed to identify solid phases and chemical functions responsible for the retention. A correlation of the intensity of retention, Rd, was pointed out whit the dipole moment µ(Orga.), providing a qualitative estimate of retention capacity for polar hydrophilic organic molecules. So, phthalate, slightly polar, displays a reversible retention (Rd ~1,6 L.kg-1), mainly on clayey phases. Citrate, very polar and strongly adsorbed (Rd ~ 40 L.kg 1), displays a persistent desorption hysteresis and an affinity to different solid phases (clayey minerals and minor oxides). Lastly, acetate, adipate and benzoate, weakly polar, display a lower affinity with rock (Rd < 0,2 L.kg-1). The diffusive behavior in compact rock of these organic anions was then studied. The effective diffusion coefficient and retardation factor values were quantified. The low diffusivity, [De/D0]ORGANIC ANIONS ~ 0,1 à 0,25 × [De/D0]WATER evidences an effect of anionic exclusion, with a same intensity as that observed for inorganic anions. Furthermore, the Kd adsorption coefficient, estimated from retarded diffusion are approximately 2 to 5 times lower than the Rd distribution coefficient measured on dispersed rock. This difference of behavior was not able to be attributed, or to kinetic effects, nor to accessible porosity to anions effects. Anyway, the complexing species display a significant diffusive retardation (Kd > 0,2 L.kg-1) consolidating the contain properties of the COx mudstone toward this species.