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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.
101

Hormonal Regulation of the Human CYP27A1 and CYP7B1 Genes

Tang, Wanjin January 2007 (has links)
CYP27A1 and CYP7B1 are widely expressed in various human tissues and are two key enzymes involved in the pathways for conversion of cholesterol to bile acids. Also, CYP27A1 is involved in bioactivation of vitamin D3 and CYP7B1 plays a role in 7alpha-hydroxylation of dehydroepiandrosterone and other steroids. Both enzymes have been reported to be relevant to prostate cell proliferation. The current study examines the hormonal regulation of CYP27A1 and CYP7B1. CYP7B1 was shown to be regulated by estrogens and androgens in human embryonic kidney HEK293 and prostate cancer LNCaP cells. Quantitation of CYP7B1 mRNA in adult and fetal human tissues showed markedly higher CYP7B1 mRNA levels in fetal tissues compared with the corresponding adult ones, except in the liver. This indicates a tissue-specific, developmental regulation of CYP7B1 and suggests an important function for this enzyme in fetal life. CYP7B1 regulation by estrogens may be of importance in fetal development and in other processes where CYP7B1 is involved, including cholesterol homeostasis, cellular proliferation, and CNS function. The regulation of CYP7B1 by sex hormones also suggests an important role for CYP7B1 in balancing prostate hormone levels in human cells. Results show that CYP27A1 can be regulated by dexamethasone, growth hormone, IGF-1, PMA, estrogens and androgens in liver-derived HepG2 cells. Dexamethasone, growth hormone and IGF-1 stimulated the promoter and endogenous activity of CYP27A1, whereas thyroid hormones and PMA inhibited CYP27A1. The regulatory effects of estrogens and androgens are different depending on the cell types. Thus, the results imply that human CYP27A1 gene is a target for estrogens and androgens, and the expression of CYP27A1 may be affected by endogenous sex hormones and pharmacological compounds with estrogenic or androgenic effects. The mechanism for the dexamethasone-induced effect on the human CYP27A1 promoter was examined. A GRE was identified important for GR-mediated regulation of CYP27A1 transcriptional activity.
102

Heck Reactions with Aryl Chlorides : Studies of Regio- and Stereoselectivity

Datta, Gopal K. January 2008 (has links)
Homogeneous palladium-catalyzed Heck vinylation of aryl chlorides was investigated under air using Herrmann’s palladacycle and the P(t-Bu)3-liberating salt [(t-Bu)3PH]BF4. Based on the results, controlled microwave heating was utilized to accelerate model Heck reactions with aryl chlorides down to 30 min employing an electron-poor olefin and a mixture of an ionic liquid and 1,4-dioxane as solvent. For the first time, a highly regioselective general protocol has been developed for palladium-catalyzed terminal (β-) arylation of acyclic vinyl ethers using inexpensive aryl chlorides as starting materials and the preligand [(t-Bu)3PH]BF4 as the key additive. This swift and straightforward protocol exploits non-inert conditions and controlled microwave heating to reduce handling and processing times, and aqueous DMF or environmentally friendly PEG-200 as the reaction medium. Somewhat higher selectivity for the linear β-product was observed in PEG-200. DFT calculations were performed at the B3LYP level of theory for the regioselectivity-determining insertion step in the Heck reaction following the neutral pathway. A series of para-substituted phenylpalladium(II) complexes was investigated in the computational study. The calculations support a ligand-driven selectivity rationale, where the electronic and steric influence of the bulky P(t-Bu)3 ligand provides improved β-selectivity. The preparative methodology was used to synthesize the β-adrenergic blocking agent Betaxolol. Highly stereoselective Pd(0)-catalyzed β-arylation and β-vinylation of a tetra-substituted cyclopentenyl ether have been accomplished using a chiral, pyrrolidine-based and substrate-bound palladium(II)-directing group under neutral reaction conditions. To the best of the author’s knowledge, this P(t-Bu)3-mediated method represents the first examples of the successful utilization of aryl and vinyl chlorides in asymmetric Heck reactions. The Heck arylation products formed were hydrolyzed and isolated as the corresponding quaternary 2-aryl-2-methyl cyclopentanones in good to moderate two-step yields with excellent stereoselectivity (90-96% ee). Inclusion of vinyl triflates under neutral reaction conditions and one aryl triflate equipped with a strongly electron-withdrawing para-cyano substituent under cationic conditions increased the preparative usefulness of the methodology. Furthermore, diastereoselective Heck arylation of both five- and six-membered cyclic vinyl ethers with aryl bromides, using the identical chiral auxiliary and suitable Pd sources, was performed. Arylated products from the tetra-substituted cyclopentenyl ether were also in this case hydrolyzed to the corresponding 2-aryl-2-methyl cyclopentanones with high to excellent enantioselectivity (85-94% ee). Despite low reaction rates and relatively modest yields, arylation reactions with the tri-substituted cyclohexenyl ether were found to be highly diastereoselective (94-98% de). Thus, an attractive supplement to direct Pd(0)-catalyzed α-arylation protocols, particularly when the use of organic chlorides, aryl bromides, and milder reaction conditions are of great importance, have been developed.
103

Involvement of the Opioid System in High Alcohol Consumption : Environmental and Genetic Influences

Ploj, Karolina January 2002 (has links)
It is well accepted that both inherent and environmental factors influence the pathogenesis of alcohol dependence. This thesis investigates the role of the opioid system in the initiation and maintenance of high ethanol intake. Ethanol-preferring C57BL/6J mice differ from ethanol-avoiding DBA/2J mice in that they exhibit lower basal levels of the opioid peptides dynorphin B and Met-enkephalin-Arg6Phe7 (MEAP) in the nucleus accumbens, which may contribute to their divergent drug-taking behaviour. Chronic ethanol intake in C57BL/6J mice and repeated ethanol administration in Sprague-Dawley rats induce time-specific changes in dynorphin B and MEAP levels in regions, such as the nucleus accumbens and the ventral tegmental area, associated with reinforcing effects of drugs of abuse. Daily neonatal handling for 15 min (H15) and maternal separation for 360 min (MS360) during postnatal day 1-21 were used as models for environmental manipulation early in life. H15 in male rats results in decreased anxiety-like behaviour, whereas MS360 increases anxiety-like behaviour. Both H15 and MS360 induce changes in dynorphin B and MEAP levels especially in regions related to the hypothalamic-pituitary-adrenal (HPA) axis. In female rats, regions related to the HPA axis are unaffected by H15. This suggests a gender-specific involvement of opioids in the HPA axis response to stress. More rats in the MS360 group initiate ethanol consumption and have a higher ethanol intake later in life than the H15 group. The H15 group has particularly low ethanol intake and also differs with regard to neurochemistry compared to both MS360 and control groups, suggesting that H15 can induce long-term changes, protective against high ethanol intake. Specific changes in opioid receptor density are observed after chronic ethanol consumption, such as an increased κ-receptor density in several brain areas, as well as changes in δ-receptor density in the frontal cortex and the nucleus accumbens. Altogether, these results suggest that the opioid system plays an important role in the mechanisms underlying the initiation and maintenance of high ethanol intake.
104

Development of sensitive EPR dosimetry methods

Gustafsson, Håkan January 2008 (has links)
Electron paramagnetic resonance (EPR) dosimetry using the well established dosimeter material alanine is a generally accepted dosimetric method for measurements of high absorbed doses. Alanine EPR dosimetry is however not sensitive enough for high precision measurements of low (< 5 Gy) absorbed doses using reasonably measurement times and small dosimeters. It has therefore not been possible to fully exploit the benefits of EPR dosimetry for applications in radiation therapy. The aim of this thesis was to show that sensitive EPR dosimetry is a competitive method for applications in radiation therapy fulfilling the requirements of measurement precision. Our strategy for reaching this goal was to search for new, more sensitive, EPR dosimeter materials fulfilling the criteria of being tissue equivalent, having a high radical yield and having a narrow EPR spectrum suitable for dosimetry. The best materials were found among formates and dithionates. Doping with small amounts of metal ions and recrystallisation in D2O were tested to further increase the sensitivity. Four promising candidate materials were tested regarding radical stability and dose response and among them lithium formate was chosen for dosimetry in radiation therapy applications. A high precision EPR dosimetry method was developed using lithium formate. The method included the development of a production method for EPR dosimeters with very homogenous shape, mass and composition. A read-out process was developed with maximal measurement precision for reasonably short measurement times. The method also included a dosimeter quality control before actual dose measurements. Measurement accuracy was controlled for every new dosimeter batch. This high precision lithium formate EPR dosimetry method was evaluated for pretreatment verifications of intensity modulated radiation therapy (IMRT) treatment plans. The precision and accuracy was shown to be sufficient (< 5 %) for measurements of doses above 1.5 Gy using one single dosimeter and a measurement time of 15 minutes. The described evaluation is therefore a demonstration of the improved precision at low dose determinations that is available with our sensitive EPR dosimeter materials. While the EPR signal intensity is proportional to absorbed dose, the signal shape is in some cases dependent on the radiation quality. A new method is presented for simultaneous measurements of beam LET (linear energy transfer) and absorbed dose in heavy charged particle beams using potassium dithionate EPR dosimetry. The study shows that when irradiating a dosimeter with 35 MeV carbon ions, the ratio of the signal amplitudes from two radicals in potassium dithionate vary along the track indicating a dependence on linear energy transfer, LET. Potassium dithionate may therefore be a promising EPR dosimeter material for simultaneous measurements of absorbed dose and LET in heavy charged particle radiation fields.
105

Neuropeptidomics – Expanding Proteomics Downwards

Svensson, Marcus January 2007 (has links)
Biological function is mainly carried out by a dynamic population of proteins which may be used as markers for disease diagnosis, prognosis, and as a guide for effective treatment. In analogy to genomics, the study of proteins is called proteomics and it is generally performed by two-dimensional gel electrophoresis and mass spectrometric methods. However, gel based proteomics is methodologically restricted from the low mass region which includes important endogenous peptides. Furthermore, the study of endogenous peptides, peptidomics, is compromised by protein fragments produced post mortem during conventional sample handling. In this thesis nanoflow liquid chromatography and mass spectrometry have been used together with improved methods for sample preparation to semi-quantitatively monitor peptides in brain tissue. The proteolysis of proteins and rise of fragments in the low mass region was studied in a time-course study up to ten minutes, where a potential marker for sample quality was found. When rapidly denatured brain tissue was analyzed, the methods enabled detection of hundreds of peptides and identifications of several endogenous peptides not previously described in the literature. The identification process of endogenous peptides has been improved by creating small targeted sequence collections from existing databases. In applications of the MPTP model for Parkinson’s disease the protein and peptide expressions were compared to controls. Several proteins were significantly changed belonging to groups of mitochondrial, cytoskeletal, and vesicle associated proteins. In the peptidomic study, the levels of the small protein PEP-19 was found to be significantly decreased in the striatum of MPTP administered animals. Using imaging mass spectrometry the spatial distribution of PEP-19 was found to be predominant in the striatum and the levels were concordantly decreased in the parkinsonian tissue as verified by immunoblotting.
106

Benefits of Non-Linear Mixed Effect Modeling and Optimal Design : Pre-Clinical and Clinical Study Applications

Ernest II, Charles January 2013 (has links)
Despite the growing promise of pharmaceutical research, inferior experimentation or interpretation of data can inhibit breakthrough molecules from finding their way out of research institutions and reaching patients. This thesis provides evidence that better characterization of pre-clinical and clinical data can be accomplished using non-linear mixed effect modeling (NLMEM) and more effective experiments can be conducted using optimal design (OD).  To demonstrate applicability of NLMEM and OD in pre-clinical applications, in vitro ligand binding studies were examined. NLMEMs were used to evaluate precision and accuracy of ligand binding parameter estimation from different ligand binding experiments using sequential (NLR) and simultaneous non-linear regression (SNLR). SNLR provided superior resolution of parameter estimation in both precision and accuracy compared to NLR.  OD of these ligand binding experiments for one and two binding site systems including commonly encountered experimental errors was performed.  OD was employed using D- and ED-optimality.  OD demonstrated that reducing the number of samples, measurement times, and separate ligand concentrations provides robust parameter estimation and more efficient and cost effective experimentation. To demonstrate applicability of NLMEM and OD in clinical applications, a phase advanced sleep study formed the basis of this investigation. A mixed-effect Markov-chain model based on transition probabilities as multinomial logistic functions using polysomnography data in phase advanced subjects was developed and compared the sleep architecture between this population and insomniac patients. The NLMEM was sufficiently robust for describing the data characteristics in phase advanced subjects, and in contrast to aggregated clinical endpoints, which provide an overall assessment of sleep behavior over the night, described the dynamic behavior of the sleep process. OD of a dichotomous, non-homogeneous, Markov-chain phase advanced sleep NLMEM was performed using D-optimality by computing the Fisher Information Matrix for each Markov component.  The D-optimal designs improved the precision of parameter estimates leading to more efficient designs by optimizing the doses and the number of subjects in each dose group.  This thesis provides examples how studies in drug development can be optimized using NLMEM and OD. This provides a tool than can lower the cost and increase the overall efficiency of drug development. / <p>My name should be listed as "Charles Steven Ernest II" on cover.</p>
107

Implementering av farmaceutiska tjänster : en litteraturstudie av faktorer som påverkar utfallet

Sheykh Sofla, Elham January 2020 (has links)
Abstrakt Bakgrund: Under lång tid har apoteksbranschen och den farmaceutiska professionen önskat utveckla farmaceutiska tjänster på öppenvårdsapotek samt få offentlig finansiering för dessa. Nya metoder som ska införas i en verksamhet tar ofta lång tid, kostar mycket och misslyckas ofta. Den process som används för att införa nya metoder i en verksamhet kallas implementering. Forskning visar att kunskap om implementering kan påverka resultatet framgångsrikt och att processen tar två till fyra år utan sådan kunskap genomförs implementeringen efter i genomsnitt 17 år. Syfte: Syftet är att identifiera vilka faktorer som kan påverka implementering av farmaceutiska tjänster på öppenvårdsapotek och belysa hur dessa faktorer påverkar implementeringen Metod: Arbetet har baserats på en litteraturstudie med hjälp av SBU:s handbok. SBU:s handbok handlar om utvärdering av metoder i hälso- och sjukvården och insatser i socialtjänsten. Artikel sökningen gjordes mellan 2020-04-08 till 2020-04-15. Totalt inkluderades 30 artiklar via databas PubMed och involverade följande termer: Cognitive service, community pharmacy, implementation science, barriers and facilitators.        Resultat: Implementering av farmaceutiska tjänster på öppenvårdsapotek är en komplex process och det finns olika faktorer som påverkar implementeringsprocessen och resultatet. De centrala begreppen för implementering är bl.a. process-modell, innovation, sammanhängande domäner av faktorer, strategier och utvärdering. Process-modellen består av fem olika delar, bland annat utforskning, förberedelse eller installation, testning och initial implementering, full verksamhet och hållbarhet. Ett vanligt ramverk som används i olika studier kallas det konsoliderade (förstärkta) ramverket för implementeringsforskning (CFIR). CFIR används för bedömning av olika faktorer som påverkar implementeringen. Faktorerna som påverkar implementeringen delas in i två grupper, hindrande (barriärer) och underlättande (faciliterande) faktorer. Slutsats: Implementering av farmaceutiska tjänster på öppenvårdsapotek påverkas av olika hindrande och underlättande faktorer. För att få en framgångsrik implementering behövs en processmodell och ett ramverk. Det behövs mer forskning för att utveckla processmodellerna och ramverket för få bättre resultat av implementering av farmaceutiska tjänster på öppenvårds apotek.
108

Användning av nya tekniker för farmaceutisk tillverkning baserade på tredimensionell utskrift.

Hammada, Abdul Majid January 2022 (has links)
Introduktion: Jämfört med traditionella procedurer erbjuder tredimensionell utskrift (3D-utskrift) av föremål en fördel när det gäller att producera mer komplexa och specialdesignade varor. 3D-utskrift är mer kostnadseffektivt och tidsbesparande jämfört med andra tillverkningsteknologier. 3D-utskriftstekniker används inom flera områden, såsom militär- och vävnadsteknik. Den skapar komplexa geometrier och har också använts för att skapa ett unikt läkemedelsfrisättningsmönster som är individuellt anpassat. Detta möjliggör lokal administrering av läkemedel till specifika organ och en mängd olika läkemedelsfrisättningsmönster. Smältdeponeringsmodellering (FDM), laserbaserade system (SLA) och selektiv lasersintring (SLS) och andra 3D-utskriftstekniker används nu i den farmaceutiska tillverkningens industri. Syfte: Syftet med detta arbete är att presentera och jämföra två 3D-utskriftstekniker som används för att framställa läkemedelsformer, nämligen FDM och SLS. Metod: Studien genomfördes som en systematisk litteraturöversikt med användning av databaserna PubMed och Web of Science. Resultat: I uppsatsen presenteras vilka läkemedelsformer som man kan tillverka med hjälp av FDM och SLS och vilka utmaningar samt för-och nackdelar som finns vid användning av de dessa tekniker. Vidare diskuteras acceptansen av nya läkemedelsformer tillverkade med 3D-utskrift. Slutsats: 3D-utskrift är en billig, snabb och enkel metod och med hjälp av denna teknik kan man skapa föremål som man aldrig har kunnat skapa tidigare. Under kommande år kommer tekniken att utvecklas snabbt, vilket gör den mer pålitlig och billigare. Baserat på resultaten ser 3D-utskrift ut att vara en teknologi under utveckling som öppnar för nya och spännande terapeutiska möjligheter. Dessutom är både FDM och SLS bättre lämpade som produktionsprocesser inom läkemedelsindustrin, där kostnadseffektivitet, reproducerbarhet, noggrannhet, precision och förmågan att tillverka olika frisättningsprofiler är avgörande.
109

Studies on Cytotoxic and Neutrophil Challenging Polypeptides and Cardiac Glycosides of Plant Origin

Johansson, Senia January 2001 (has links)
<p>This thesis examines the isolation and characterisation (biological and chemical) of polypeptides from plants. A fractionation protocol was developed and applied on 100 plant materials with the aim of isolating highly purified polypeptide fractions from small amounts of plant materials. The polypeptide fractions were analysed and evaluated for peptide content and biological activities. A multitarget functional bioassay was optimised as a method for detecting substances interacting with the inflammatory process of activated neutrophil granulocytes. In this assay, the neutrophil was challenged with an inflammatory mediator, <i>N</i>-formyl methionyl-leucyl-phenylalanine (fMLP), or with platelet activating factor (PAF), to induce exocytotic release of the enzyme elastase, which then was quantified by photometric determination of the product p-nitroanilide (pNA) formed from a chromogenic substrate for elastase. Of the tested extracts, 41% inhibited pNA formation more than 60%, and 3% stimulated formation.</p><p>Phoratoxin B and four new peptides, phoratoxins C-F, were isolated from <i>Phoradendron tomentosum</i>. In addition, the cardiac glycoside digitoxin was isolated from <i>Digitalis purpurea</i>. All these substances expressed cytotoxicity and a neutrophil challenging activity.</p><p>Phoratoxins C-F were similar to earlier described phoratoxins A and B, which belong to the group of thionins. All the peptides were evaluated for cytotoxicity in a human cell line panel. Phoratoxin C was the most potent towards the cell lines (mean IC<sub>50</sub>: 160 nM), and was therefore investigated further on tumour cells from patients. Correlation analysis of the log IC<sub>50</sub> values indicated a mechanism of action different from clinically used archetypal cytotoxic drugs. Phoratoxin C also showed selective toxicity to the solid tumours when compared to the haematological cancer types. The phoratoxin C was 18 times more potent towards the solid tumour samples from breast cancer cells (87 nM) compared to the tested haematological malignancies.</p><p>The structure-activity relationship concerning cytotoxicity was evaluated for digitoxin and related cardiac glycosides. Digitoxin was shown to be potent, with the average IC<sub>50</sub> 37 nM being within the therapeutic concentration used for cardiac congestion (13-45 nM). Digitoxin expressed selective toxicity towards solid tumours from patients compared to haematological malignancies.</p>
110

Synthesis of Aldehyde-Functionalized Building Blocks and Their Use for the Cyclization of Peptides : Applications to Angiotensin II

Johannesson, Petra January 2002 (has links)
<p>This study addresses the issue of how to convert peptides into drug-like non- peptides with retained biological activities at peptide receptors. Angiotensin II (Asp-Arg-Val-Tyr-Ile-His-Pro-Phe, Ang II) was used as a model peptide. </p><p>Knowledge of the bioactive conformations of endogenous peptides is invaluable for the conversion of peptides into less peptidic analogues. Effectively constrained cyclic analogues, with retained pharmacological activities, may provide valuable information about the bioactive conformations of the peptide in question. </p><p>This thesis describes the development of synthesis for a number of protected, aldehyde-functionalized building blocks for standard solid phase peptide synthesis, and their use for the preparation of cyclic peptide analogues. The effect of variations in the side-chain lengths of the building blocks, on the outcome of the cyclizations was studied. Incorporation of a building block derived from L-aspartic acid afforded bicyclization towards the C-terininal end of the peptide, while for the corresponding L-glutamic acid derived building block, N-terminal directed bicyclization was achieved. A building block derived from L-2-aminoadipic acid was exploited for monocyclization furnishing <i>cis-</i> and <i>trans-</i> vinyl sulfide bridged peptide analogues. </p><p>The described cyclization methods have been applied to the synthesis of a number of conformationally constrained Ang II analogues, for which the pharmacological properties have been evaluated. Two of the Ang II analogues synthesized displayed high affinities and full agonist activities at the AT<sub>1</sub> angiotensin receptor, and have proven to be useful tools in the search for the bioactive conformation of Ang II.</p>

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