Coming dissertations at Uppsala university
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Metabolite Profiling of Drugs using Mass Spectrometry : Identification of analytical targets for doping control and improvements of the metabolite search process
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-521781
Doping is defined as the use of prohibited substances or methods by the World Anti-Doping Agency and the aim with doping control analysis is to detect the use of these illicit substances or methods. Substances that are prohibited in human or equine sports have either a positive or negative impact on the performance. Since administered drugs generally are metabolized to a varying degree and thereby not only excreted in their original form, their metabolite profiles are of high interest because drug metabolites may be present in the body for a longer time than the administered drug itself. Thereby detection of metabolites can improve the window of detection. Unfortunately, the metabolite profiles of non-approved drugs that are mainly available on the Internet, such as Selective Androgen Receptor Modulators (SARMs) are often unknown.
This thesis consists of four papers that all encompass drug metabolite profiling either in vivo, in vitro or in a combination, utilizing separation with liquid chromatography and detection with high resolution mass spectrometry. In paper I and II, the equine in vivo metabolite profiles of the two SARMs ACP-105 and LGD-3303 were investigated and the results showed that using drug metabolites as analytical targets can prolong the detection time. For ACP-105, the in vivo metabolite profile was compared with different incubation models such as liver microsomes, S9 fractions and the fungus Cunninghamella elegans. The in vivo and in vitro metabolite profiles showed an interesting overlap for several metabolites, demonstrating the importance and usefulness for in vitro methods in doping control, especially since microsome incubates are allowed as reference material. An optimization of microsome incubation conditions utilizing experimental design was presented in paper III and IV, showing that the optimized conditions greatly impacted the yield of drug metabolites, but also that the optimal conditions are substance dependent. In paper III, a multivariate data analysis search tool utilizing OPLS-DA was presented, which greatly simplified the in vitro drug metabolite identification process of ACP-105 and the results showed relevance in comparison with human in vivo metabolites.
In conclusion, several new analytical targets with improved detectability for equine and human doping control have been presented, where the drug metabolite profile showed to be of great importance. All together, these new analytical targets, the optimized microsome incubation conditions for improved metabolite yield and the search tool that aids the metabolite investigation through multivariate data analysis, have made a positive contribution to the doping control area.
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Advanced molecular tools for diagnostic analyses of RNA and antibodies in situ and in solution
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-522118
Advanced molecular diagnostics uses in vitro biological assays to detect nucleic acids or proteins even in low concentrations across samples, allowing for the identification of biomarkers, monitoring the course of the disease over time, and selection of appropriate therapy. In this thesis, I focus on development and early applications of several molecular tools of expected value in research, and eventually also clinically.
In papers I and II, proximity extension assay (PEA) was for the first time modified to measure specific antibody responses, rather than protein levels as in the standard PEA. We call the method AbPEA and the technique was used to sensitively measure antibody responses to the spike protein or the nucleocapsid of SARS-CoV-2. We demonstrated that AbPEA has high specificity, sensitivity, and broad dynamic range, along with multiplexing potential, offering performance similar to that of other methods for antibody measurements. We demonstrated utilization of blood and saliva samples in paper I and paper II, respectively, which further establish that our approach has great potential for large-scale screening and biobanking.
In paper III, we aimed to investigate how the protein composition of extracellular vesicles (EVs) differed among blood samples collected from healthy individual or ones with either mild or severe COVID-19. Proximity barcoding assay was applied to obtain a comprehensive overview of the protein composition of large numbers of individual EVs, demonstrating interesting differences.
In paper IV, we enhanced padlock-RCA-based RNA genotyping in situ by using another newly developed technology for highly selective detection of DNA or RNA sequence variants, referred to as super RCA (sRCA). Our analysis showed that this approach can improve the selectivity for sequence variants during in situ detection of mutant or wild-type transcripts, and the signals representing superRCA reaction products are prominent and easily distinguished from any background.
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Exploring Reaction Pathways in Li-ion Batteries with Operando Gas Analysis
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-522294
The reliance on Li-ion batteries is increasing as we transition from fossil fuels to renewable energy sources. Despite their widespread use, a gap remains in understanding certain processes within these batteries, especially regarding the solid electrolyte interphase (SEI) and the impact of side reactions on Li-ion batteries. A custom-made Online Electrochemical Mass Spectrometry (OEMS) instrument was designed to explore these aspects. The OEMS instrument was validated through the study of gas-evolving reactions in the classic LiCoO2 | Graphite system. In-depth studies focusing on the reaction pathways of ethylene carbonate, the archetype Li-ion battery electrolyte solvent, identified the specific reaction pathways contributing to SEI formation. Moreover, ethylene carbonate’s interaction with residual contaminants like OH– from H2O reduction was explored. It was revealed that the integrity of the SEI can be compromised by minor amounts of contaminants, establishing a competitive dynamic at the negative electrode surface between ethylene carbonate and residual contaminants such as H2O and HF. Additionally, the roles of additives like vinylene carbonate and lithium bis(oxolato) borate in SEI formation were explored. Vinylene carbonate was shown to form a layer on the negative electrode, but also scavenge protons and H2O, revealing that it is a multi-functional additive. Lithium bis(oxolato) borate on the other hand formed an SEI layer before H2O reduction, blocking the residual contaminant and ethylene carbonate from reaching the electrode surface. By providing insights into the negative electrode’s interphase and SEI formation through a custom-made OEMS instrument, this research underscores the complexity of reaction pathways and the necessity of considering both major and minor, as well as, primary and secondary reactions for a holistic understanding of Li-ion batteries.