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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Longitudinal Models for Quantifying Disease and Therapeutic Response in Multiple Sclerosis

Novakovic, Ana M. January 2017 (has links)
Treatment of patients with multiple sclerosis (MS) and development of new therapies have been challenging due to the disease complexity and slow progression, and the limited sensitivity of available clinical outcomes. Modeling and simulation has become an increasingly important component in drug development and in post-marketing optimization of use of medication. This thesis focuses on development of pharmacometric models for characterization and quantification of the relationships between drug exposure, biomarkers and clinical endpoints in relapse-remitting MS (RRMS) following cladribine treatment. A population pharmacokinetic model of cladribine and its main metabolite, 2-chloroadenine, was developed using plasma and urine data. The renal clearance of cladribine was close to half of total elimination, and was found to be a linear function of creatinine clearance (CRCL). Exposure-response models could quantify a clear effect of cladribine tablets on absolute lymphocyte count (ALC), burden of disease (BoD), expanded disability status scale (EDSS) and relapse rate (RR) endpoints. Moreover, they gave insight into disease progression of RRMS. This thesis further demonstrates how integrated modeling framework allows an understanding of the interplay between ALC and clinical efficacy endpoints. ALC was found to be a promising predictor of RR. Moreover, ALC and BoD were identified as predictors of EDSS time-course. This enables the understanding of the behavior of the key outcomes necessary for the successful development of long-awaited MS therapies, as well as how these outcomes correlate with each other. The item response theory (IRT) methodology, an alternative approach for analysing composite scores, enabled to quantify the information content of the individual EDSS components, which could help improve this scale. In addition, IRT also proved capable of increasing the detection power of potential drug effects in clinical trials, which may enhance drug development efficiency. The developed nonlinear mixed-effects models offer a platform for the quantitative understanding of the biomarker(s)/clinical endpoint relationship, disease progression and therapeutic response in RRMS by integrating a significant amount of knowledge and data.
182

Chemical Derivatization in Combination with Liquid Chromatography Tandem Mass Spectrometry for Detection and Structural Investigation of Glucuronides

Lampinen Salomonsson, Matilda January 2008 (has links)
This thesis presents novel approaches for structural investigation of glucuronides using chemical derivatization in combination with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MSn). Today, LC-ESI-MSn is the dominant technique for quantitative as well as qualitative analyses of metabolites, due to its high sensitivity and selectivity. However, for compounds without an easily ionizable group, e.g., steroids, the sensitivity is limited. In the work presented in this thesis, a derivatization procedure forming a basic oxime significantly increased the detection sensitivity for the altrenogest glucuronide. Furthermore, in structural evaluations of glucuronides, the limitation of LC-MSn becomes evident due to the initial neutral loss of 176 u, i.e. monodehydrated glucuronic acid, which often makes it impossible to elucidate the structures of the conjugates. To solve this problem, the main part of the work described in this thesis was devoted to chemical derivatization as a means of facilitating the determination of the site of conjugation. For the first time, the isomeric estriol glucuronides were evaluated using a combination of three reagents 2-chloro-1-methylpyridinium iodide (CMPI), 1-ethyl-3-(3-dimethyl- aminopropyl)-carbodiimide (EDC), and 2-picolylamine (PA). Interestingly, the derivatization gave a selective fragmentation pattern leading to differentiation of the isomers. Another derivatization reagent, 1,2-dimethylimidazole-4-sulfonyl chloride (DMISC), was also tested for the first time in structural investigations. The isomeric glucuronides of morphine, formoterol, and hydroxypropranolol were evaluated. They can all be conjugated in aliphatic as well as aromatic positions. DMISC was proven to be useful in two ways. Firstly, the morphine and formoterol glucuronides that contained a free phenol could be differentiated from those that were conjugated in the aromatic position based on different reactivity. Secondly, for the aromatic O-glucuronide of 4’-hydroxypropranolol, DMISC was proven to react with the amine. This product gave a different fragmentation pattern compared to the corresponding derivative of the aliphatic glucuronide.
183

Following the mevalonate pathway to bone heal alley

Skoglund, Björn January 2007 (has links)
The mevalonate pathway is an important biosynthetic pathway, found in all cells of virtually all known pro- as well as eukaryotic organisms. This thesis is an investigation into the use of two drugs, originally developed for different applications, but both affecting the mevalonate pathway, in to models of fracture repair. Using two different rodent models of fracture repair, a commonly used cholesterol lowering drug (statin) and two drugs used to treat osteoporosis (bisphosphonate) were applied both systemically as well as locally in order to enhance fracture repair. Papers I and II investigate the potential of simvastatin to improve the healing of femoral fractures in mice. Papers III and IV explore the use of two bisphosphonates to improve early fixation of stainless steel screws into rat bone. The statin simvastatin lead to an increased strength of the healing cellus. The application of bisphosphonates increased early screw fixation. It seems clear that both drugs have uses in orthopaedic applications. One interesting avenue of further research would be to combine the two classes of drugs and see if we can get the benefits while at the same time diminishing the drawbacks.
184

Novel Fatty Acid Dioxygenases of Human and Plant Pathogenic Fungi : Studies by Gene Deletion and Expression

Jernerén, Fredrik January 2011 (has links)
The dioxygenase-cytochrome P450 fusion proteins (DOX-CYP) comprise a heme-containing enzyme family that shares structural and catalytic properties with mammalian prostaglandin H (PGH) synthases. 7,8-Linoleate diol synthase (7,8-LDS) of Gaeumannomyces graminis was first characterized, and DOX-CYP enzymes are of mechanistic and biological interest. The growing number of fungal genome sequences has revealed DOX-CYP homologues in medically and economically important species. The aim of this thesis was to identify novel members of the DOX-CYP fusion protein family. The devastating rice pathogen Magnaporthe oryzae contains two DOX-CYP genes. The fungus synthesizes 7S,8S-dihydroxyoctadecadienoic acid (7,8-DiHODE) by dioxygenation of linoleic acid to 8R-hydroperoxyoctadecadienoic acid (8R-HPODE), and subsequent isomerisation to the diol. 7,8-LDS of M. oryzae was identified by gene deletion, but the infection and reproduction processes of the Δ7,8-LDS strain were not altered. A mutant with constitutive protein kinase A activity profoundly changed the oxygenation profile, possibly due to post-translational modification. The human pathogens Aspergillus fumigatus and A. clavatus contain three DOX-CYP, designated psi producing oxygenase A (ppoA), ppoB, and ppoC, and form three oxylipins: 5S,8R-DiHODE, 8R,11S-DiHODE, and 10R-hydroxyoctadecadienoic acid.  PpoA was identified as 5,8-LDS, and ppoC as 10R-DOX. The 8,11-linoleate hydroperoxide isomerase activity was reduced by two imidazole-containing P450 inhibitors, miconazole and 1-benzylimidazole. PpoB could not be linked to the biosynthesis of 8,11-DiHODE for the following reasons: First, the 8,11-hydroperoxide isomerase activity was retained in A. fumigatus ΔppoB strains. Second, the P450 domain of the deduced ppoB of A. clavatus lacks a heme-thiolate cysteine ligand, presumably essential for hydroperoxide isomerase activity. Linoleate 9R-DOX activities of Aspergillus terreus and Lasiodiplodia theobromae were discovered. 9R-HPODE was further converted into unstable allene oxides, as judged by the accumulation of their hydrolysis products, α- and γ-ketols. These allene oxide synthase activities were specific for 9R-hydroperoxides. The 9R-DOX and AOS were found to have unique characteristics. In conclusion, novel DOX-CYP enzymes were identified in human and plant pathogenic fungi. These enzymes might be involved in biological processes, and show interesting catalytic similarities to human PGH synthase and thromboxane synthase (CYP5A).
185

Psychoactive prescription drug use disorders, misuse and abuse : Pharmacoepidemiological aspects

Tjäderborn, Micaela January 2016 (has links)
Background: There is a widespread and increasing use of psychoactive prescription drugs, such as opioid analgesics, anxiolytics, hypnotics and anti-epileptics, but their use is associated with a risk of drug use disorder, misuse and abuse. Today, these are globally recognized and emerging public health concerns. Aim: The aim of this thesis is to estimate the prevalence of psychoactive prescription drug (PPD) use disorders, misuse and abuse, and to investigate the association with some potential risk factors. Methods: A study using register data from forensic cause of death investigations investigated and described cases of fatal unintentional intoxication with tramadol (Study I). Based on register data on spontaneously reported adverse drug reactions (ADRs) reported cases of tramadol dependence were investigated and summarised (Study II). In a study in suspected drug-impaired drivers with a toxicology analysis confirming the intake of one out of five pre-specified PPDs, the prevalence of non-prescribed use was assessed and associated factors were investigated (Study III). From a cohort of patients initiating prescribed treatment with pregabalin, using data on prescription fills, a study investigated longitudinal utilisation patterns during five years with regards to use of the drug above the maximum approved daily dose (MAD), and factors associated with the utilisation patterns (Study IV). Results: In the first study, 17 cases of unintentional intoxications were identified, of which more concerned men, the median age was 44 years and the majority used multiple psychoactive substances (alcohol, illicit drugs and prescription drugs). The second study identified 104 spontaneously reported cases of tramadol dependence, in which more concerned women, the median age was 45 years, and a third reported a history of substance abuse and 40% of past psychoactive medication use. In the third study, more than half of the individuals suspected of drug-impaired driving used the drug without a recent prescription. Non prescribed use was most frequent in users of benzodiazepines and tramadol, and was more likely in younger individuals and in multiple-substance users. In the last paper five longitudinal utilisation patterns were found in pregabalin users, with two patterns associated with a particularly high risk of doses above the maximum approved dosing recommendation. This pattern of use was associated with male sex, younger age, non-urban residency and a recent prescribed treatment with an antiepileptic or opioid analgesic drug. Conclusions: This thesis shows that psychoactive prescription drug use disorders, misuse and abuse occur and may have serious and even fatal consequences. The prevalence varies between different drugs and populations. Abuse and misuse seem to be more common in young people. Fatal intoxications and misuse of prescribed drugs may be more common in men, while drug use disorders following prescribed treatment may be more common in women and non-prescribed use equally distributed between women and men. Individuals with a history of mental illness, substance use disorder or abuse, or of past use of psychoactive medications are likely important risk groups. In summary, the findings suggest a potential for improvements in the utilisation of psychoactive prescription drugs. The results may be useful in the planning of clinical and regulatory preventive interventions to promote the rational, individualised and safe use of such drugs.
186

En utvärdering av 5-HT1A-receptoragonisten vilazodone för en utökad antidepressiv effekt i behandlingen av egentlig depression / Evaluation of the antidepressant effect of vilazodone for the treatment of major depression

Khalifa, Aseel January 2017 (has links)
Major depressive disorder (MDD) is a mood disorder majorly responsible for disability and mortality worldwide. With a lifetime prevalence of 15-20%, it is the main cause of functional impairment in Western societies as well as the fourth most debilitating illness in the world. Although the pathophysiology of MDD is not yet fully understood, some evidence that suggest the presence of a neuroanatomical deficiency have given rise to the theory of a specific imbalance in the monoamine neurotransmitters noradrenaline (NA) and/or serotonin (5-HT) levels in the brain. Overall, the various classes of antidepressant agents that have been developed to increase monoamine levels on the basis of this proposal have been successful. However, facts relating to prevalent escalation in the illness and recurring episodes of depression point towards a need to enhance clinical treatment. Most conventional antidepressants such as selective serotonin reuptake inhibitors (SSRI) and selective serotonin and noradrenaline inhibitors (SNRI) pose problems in symptomatic improvement. These include therapeutic lag, safety and tolerability issues, making more than 30% patients with MDD unable to reach adequate relief. In this respect, the action mechanism has moved beyond conventional SSRI and lead to the introduction of vilazodone, a novel antidepressant with an additional 5-HT1A partial agonist profile argued to be of potential benefit for a greater efficacy, faster onset of action and better tolerability. Using secondary data, this project aimed to evaluate the role of vilazodone as a SPARI-drug in the overall clinical treatment of MDD as well as its potential in addressing some of the most common obstacles in antidepressant treatment. Study results proved vilazodone’s efficacy to be superior to placebo. Patients across all studies showed significant improvement in depressive symptoms measured in MADRS and HAMD17. Vilazodone was also shown to be generally safe and tolerable but was not positively distinguished from placebo with regards to adverse effects. An overall, meaningful improvement in depressive symptoms was demonstrated in vilazodone, which reinforces its merit as an important treatment option for patients with MDD.
187

Strategic Supply Chain Optimization for Generic Pharmaceuticals : Improving the triple bottom line by postponing product completion

Arjang Eslumuand Quch Tape, Hanif, Ismail, Liban Ahmed January 2019 (has links)
Generic pharmaceutical supply chains are complex, interfacing humanitarian needs, industrial manufacturing, regulatory bodies and numerous other shareholders. This report gives a brief introduction to a current supply chain process within a company as well as a proposal to improve the supply chain financially, socially and environmentally. Data has been collected mainly through interviews and literature studies in order to conduct a case study. The project included an initial business case, calculations of necessary data in order to justify the work as well as to quantify the results. The main part of the proposal is to postpone the packing of medical products to a later stage as a way of improving the triple bottom line. Theoretically, this change results in lower ordering costs, lower volumes scrapped and thus lower scrapping costs and pollution, a decrease in order volumes further reducing costs and pollution and more. The study met the intended outcomes and would theoretically improve the company in line with the set targets. At the time of writing it is yet unclear whether it will lead to any action on behalf of the company. / Försörjningskedjorna inom farmaceutisk generika är komplexa med många externa beröringspunkter såsom mänskligt behov, industriell produktion, regulatoriska organisationer och andra intressenter. Den här rapporten erbjuder en kort introduktion till den befintliga försörjningsprocessen i ett företag i branschen samt ett förslag till hur företaget kan förbättra sin försörjningskedja ur ett ekonomiskt, socialt och miljömässigt perspektiv. Information har inhämtats främst genom intervjuer och litteraturstudier som har utgjort grund för en fallstudie. Projektet inkluderade framtagning av ett beslutsunderlag, datakalkyler för att ge stöd åt syftet med arbetet samt för att kvantifiera resultaten. Huvuddelen av förslaget utgörs av senareläggningen av packningsstadiet för medicinska produkter och effekten det får på det som på engelska kallas triple bottom line. Implementeringen av projektet ska teoretiskt leda till bland annat förbättrade vinstmarginaler, lägre andel kassationer och därmed en minskning av kostnader och utsläpp hänförliga till kassationer, lägre ordervolymer vilket i sin tur leder till sänkta kostnader och utsläpp. Studien har gett ett positivt utfall relativt målsättningen och implementeringen ska teoretiskt leda till en förbättring av verksamheten i linje med de uppsatta målen. I skrivande stund är det oklart huruvida företaget kommer att implementera förslaget.
188

Pharmacometrics Modelling in Type 2 Diabetes Mellitus : Implications on Study Design and Diabetes Disease Progression

Ghadzi, Siti Maisharah Sheikh January 2017 (has links)
Pharmacometric modelling is widely used in many aspects related to type 2 diabetes mellitus (T2DM), for instance in the anti-diabetes drug development, and in quantifying the disease progression of T2DM. The aim of this thesis were to improve the design of early phase anti-diabetes drug development studies with the focus on the power to identify mechanism of drug action (MoA), and to characterize and quantify the progression from prediabetes to overt diabetes, both the natural progression and the progression with diet and exercise interventions, using pharmacometrics modelling. The appropriateness of a study design depends on the MoAs of the anti-hyperglycaemic drug. Depending on if the focus is power to identify drug effect or accuracy and precision of drug effect, the best design will be different. Using insulin measurements on top of glucose has increase the power to identify a correct drug effect, distinguish a correct MoA from the incorrect, and to identify a secondary MoA in most cases. The accuracy and precision of drug parameter estimates, however, was not affected by insulin. A natural diabetes disease progression model was successfully added in a previously developed model to describe parameter changes of glucose and insulin regulation among impaired glucose tolerance (IGT) subjects, with the quantification of the lifestyle intervention. In this model, the assessment of multiple short-term provocations was combined to predict the long-term disease progression, and offers apart from the assessment of the onset of T2DM also the framework for how to perform similar analysis. Another previously published model was further developed to characterize the weight change in driving the changes in glucose homeostasis in subjects with IGT. This model includes the complex relationship between dropout from study and weight and glucose changes. This thesis has provided a first written guidance in designing a study for pharmacometrics analysis when characterizing drug effects, for early phase anti-diabetes drug development. The characterisation of the progression from prediabetes to overt diabetes using pharmacometrics modelling was successfully performed. Both the natural progression and the progression with diet and exercise interventions were quantified in this thesis.
189

High-throughput screening using multicellular tumor spheroids to reveal and exploit tumor-specific vulnerabilities

Senkowski, Wojciech January 2017 (has links)
High-throughput drug screening (HTS) in live cells is often a vital part of the preclinical anticancer drug discovery process. So far, two-dimensional (2D) monolayer cell cultures have been the most prevalent model in HTS endeavors. However, 2D cell cultures often fail to recapitulate the complex microenvironments of in vivo tumors. Monolayer cultures are highly proliferative and generally do not contain quiescent cells, thought to be one of the main reasons for the anticancer therapy failure in clinic. Thus, there is a need for in vitro cellular models that would increase predictive value of preclinical research results. The utilization of more complex three-dimensional (3D) cell cultures, such as multicellular tumor spheroids (MCTS), which contain both proliferating and quiescent cells, has therefore been proposed. However, difficult handling and high costs still pose significant hurdles for application of MCTS for HTS. In this work, we aimed to develop novel assays to apply MCTS for HTS and drug evaluation. We also set out to identify cellular processes that could be targeted to selectively eradicate quiescent cancer cells. In Paper I, we developed a novel MCTS-based HTS assay and found that nutrient-deprived and hypoxic cancer cells are selectively vulnerable to treatment with inhibitors of mitochondrial oxidative phosphorylation (OXPHOS). We also identified nitazoxanide, an FDA-approved anthelmintic agent, to act as an OXPHOS inhibitor and to potentiate the effects of standard chemotherapy in vivo. Subsequently, in Paper II we applied the high-throughput gene-expression profiling method for MCTS-based drug screening. This led to discovery that quiescent cells up-regulate the mevalonate pathway upon OXPHOS inhibition and that the combination of OXPHOS inhibitors and mevalonate pathway inhibitors (statins) results in synergistic toxicity in this cell population. In Paper III, we developed a novel spheroid-based drug combination-screening platform and identified a set of molecules that synergize with nitazoxanide to eradicate quiescent cancer cells. Finally, in Paper IV, we applied our MCTS-based methods to evaluate the effects of phosphodiesterase (PDE) inhibitors in PDE3A-expressing cell lines. In summary, this work illustrates how MCTS-based HTS yields potential to reveal and exploit previously unrecognized tumor-specific vulnerabilities. It also underscores the importance of cell culture conditions in preclinical drug discovery endeavors.

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