<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 IC₅₀: 160 nM), and was therefore investigated further on tumour cells from patients. Correlation analysis of the log IC₅₀ 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 IC₅₀ 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>

<p>Transport into and across the cells of the human body is a prerequisite for the pharmacological action of drugs. Passive membrane permeability and active transport mechanisms are major determinants of the intestinal absorption of drugs, as well as of the distribution to target tissues and the subsequent metabolism and excretion from the body. In this thesis, the role of ATP-binding cassette (ABC) transporters and passive permeability on drug absorption and disposition was investigated. Particular emphasis was placed on defining the molecular properties important for these transport mechanisms. </p><p>The influence of different transport pathways on predictions of intestinal drug absorption was investigated using experimental models of different complexity. Experimental models that include the paracellular pathway gave improved predictions of intestinal drug absorption, especially for incompletely absorbed drugs. Further, the inhibition of the ABC transporters breast cancer resistance protein (BCRP/ABCG2) and multidrug-resistance associated protein 2 (MRP2/ABCC2) was experimentally investigated using structurally diverse datasets that were representative of orally administered drugs. A large number of previously unknown inhibitors were identified among registered drugs, but their clinical relevance for drug-drug interactions and drug-induced toxicity remains to be determined. The majority of the inhibitors affected all three major ABC transporters BCRP, MRP2 and P-glycoprotein (P gp/ABCB1), and these multi-specific inhibitors were found to be enriched in highly lipophilic weak bases. </p><p>To summarize, the present work has led to an increased knowledge of the molecular features of importance for ABC transporter inhibition and passive membrane permeability. Previously unknown ABC transporter inhibitors were identified and predictive computational models were developed for the different drug transport mechanisms. These could be valuable tools to assist in the prioritization of experimental efforts in early drug discovery.</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, N-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. Phoratoxin B and four new peptides, phoratoxins C-F, were isolated from Phoradendron tomentosum. In addition, the cardiac glycoside digitoxin was isolated from Digitalis purpurea. All these substances expressed cytotoxicity and a neutrophil challenging activity. 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 IC50: 160 nM), and was therefore investigated further on tumour cells from patients. Correlation analysis of the log IC50 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. The structure-activity relationship concerning cytotoxicity was evaluated for digitoxin and related cardiac glycosides. Digitoxin was shown to be potent, with the average IC50 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.

Transport into and across the cells of the human body is a prerequisite for the pharmacological action of drugs. Passive membrane permeability and active transport mechanisms are major determinants of the intestinal absorption of drugs, as well as of the distribution to target tissues and the subsequent metabolism and excretion from the body. In this thesis, the role of ATP-binding cassette (ABC) transporters and passive permeability on drug absorption and disposition was investigated. Particular emphasis was placed on defining the molecular properties important for these transport mechanisms. The influence of different transport pathways on predictions of intestinal drug absorption was investigated using experimental models of different complexity. Experimental models that include the paracellular pathway gave improved predictions of intestinal drug absorption, especially for incompletely absorbed drugs. Further, the inhibition of the ABC transporters breast cancer resistance protein (BCRP/ABCG2) and multidrug-resistance associated protein 2 (MRP2/ABCC2) was experimentally investigated using structurally diverse datasets that were representative of orally administered drugs. A large number of previously unknown inhibitors were identified among registered drugs, but their clinical relevance for drug-drug interactions and drug-induced toxicity remains to be determined. The majority of the inhibitors affected all three major ABC transporters BCRP, MRP2 and P-glycoprotein (P gp/ABCB1), and these multi-specific inhibitors were found to be enriched in highly lipophilic weak bases. To summarize, the present work has led to an increased knowledge of the molecular features of importance for ABC transporter inhibition and passive membrane permeability. Previously unknown ABC transporter inhibitors were identified and predictive computational models were developed for the different drug transport mechanisms. These could be valuable tools to assist in the prioritization of experimental efforts in early drug discovery.

Gold nanoparticles exhibit a combination of physical, chemical, optical, and electronic properties unique from all other nanotechnologies. These structures can provide a highly multifunctional platform with which to diagnose and treat diseases and can dramatically enhance a variety of photonic and electronic processes and devices. The work herein highlights some newly emerging applications of these phenomena as they relate to the targeted diagnosis and treatment of cancer, improved charge carrier generation in photovoltaic device materials, and strategies for enhanced spectrochemical analysis and detection. Chapter 1 introduces the reader to the design, synthesis, and molecular functionalization of gold nanotechnologies, and provides a framework from which to discuss the unique photophysical properties and applications of these nanoscale materials and their physiological interactions in Chapter 2. Chapter 3 discusses ongoing preclinical research in our lab investigating the use of near-infrared absorbing gold nanorods as photothermal contrast agents for laser ablation therapy of solid tumors. In Chapter 4, we present recent work developing a novel strategy for the targeted treatment of hormone-dependent breast and prostate tumors using multivalent gold nanoparticles that function as highly selective and potent endocrine receptor antagonist chemotherapeutics. In Chapter 5, we discuss a newly-emerging tumor-targeting strategy for nanoscale drug carriers which relies on their selective delivery to immune cells that exhibit high accumulation and infiltration into breast and brain tumors. Using this platform, we further investigate the interactions of nanoscale drug carriers and imaging agents to a transmembrane protein considered to be the single most prevalent and single most important contributor to drug resistance and the failure of chemotherapy. Chapter 6 presents work from a series of studies exploring enhanced charge carrier generation and relaxation in a hybrid electronic system exhibiting resonant interactions between photovoltaic device materials and plasmonic gold nanoparticles. Chapter 7 concludes by presenting studies investigating the contributions from so-called “dark” plasmon modes to the spectrochemical diagnostic method known as surface enhanced Raman scattering.

Membrane transport proteins are known to influence the absorption, distribution, metabolism, excretion and toxicity (ADMET) of drugs. At the onset of this thesis work, only a few structure-activity models, in general describing P-glycoprotein (Pgp/ABCB1) interactions, were developed using small datasets with little structural diversity. In this thesis, drug-transport protein interactions were explored using large, diverse datasets representing the chemical space of orally administered registered drugs. Focus was set on the ATP-binding cassette (ABC) transport proteins expressed in the canalicular membrane of human hepatocytes. The inhibition of the ABC transport proteins multidrug-resistance associated protein 2 (MRP2/ABCC2) and bile salt export pump (BSEP/ABCB11) was experimentally investigated using membrane vesicles from cells overexpressing the investigated proteins and sandwich cultured human hepatocytes (SCHH). Several previously unknown inhibitors were identified for both of the proteins and predictive in silico models were developed. Furthermore, a clear association between BSEP inhibition and clinically reported drug induced liver injuries (DILI) was identified. For the first time, an in silico model that described combined inhibition of Pgp, MRP2 and breast cancer resistance protein (BCRP/ABCG2) was developed using a large, structurally diverse dataset. Lipophilic weak bases were more often found to be general ABC inhibitors in comparison to other drugs. In early drug discovery, in silico models can be used as predictive filters in the drug candidate selection process and membrane vesicles as a first experimental screening tool to investigate protein interactions. In summary, the present work has led to an increased understanding of molecular properties important in ABC inhibition as well as the potential influence of ABC proteins in adverse drug reactions. A number of previously unknown ABC inhibitors were identified and predictive computational models were developed.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2005. / Härtill 4 uppsatser. På omsl. felaktigt " ... daunorobicin ..."

Philosophiae Doctor - PhD (Chemistry) / Tuberculosis (TB) is an airborne disease caused by Mycobacterium tuberculosis (MTB) that usually affects the lungs leading to severe coughing, fever and chest pains. It was estimated that over 9.6 million people worldwide developed TB and 1.5 million died from the infectious disease of which 12 % were co-infected with human immunodeficiency virus (HIV) in the year 2015. In 2016 the statistics increased to a total of 1.7 million people reportedly died from TB with an estimated 10.4 million new cases of TB diagnosed worldwide. The development of the efficient point-of-care systems that are ultra-sensitive, cheap and readily available is essential in order to address and control the spread of the tuberculosis (TB) disease and multidrugresistant tuberculosis.

This diploma thesis summarizes knowledge of significant genetically contitioned deseases occurring in border collies. There is described a total of 14 diseases, some with the location of causal mutation not yet known. Primary focus of this thesis is g.4411956_4411960delGTTT mutation of gene VPS13B causing Trapped Neuthrophil Syndrome (TNS), MDR1 gene's mutation AF045016.1: c.227_230delATAG associated with multidrug resistance (MDR1) and CUBN gene's mutation c.8392delC which causes intestinal malabsorption of cobalamin by another name ImerslundGräsbeck syndrome (IGS). A genotype analysis of 89 border collies with a proof of origin was performed. The DNA was extracted from buccal mucosal swabs, the isolation of DNA was performed by Chelex-100 from the native material. The analysis was proceeded by optimized PCR-RFLP method using restrictive MboI (MDR1) and Msl I (IGS) enzymes. There were detected 4 g.4411956_4411960delGTTT mutation vectors causing TNS. As for the MDR1 and IGS there wasn't detected any affected case.

The purpose of the study was to investigate and describe the experiences of a mobile injection team for multi drug resistant-tuberculosis outpatients, and to design and recommend a mobile injection team guideline based on the experiences of the team members in Ugu District, KwaZulu-Natal and to indicate the support that the MIT require. Phenomenological research was conducted. Convenient census sampling was used as all the seven members of the Ugu District mobile injection team were included. The inclusion criteria was at least six months’ working experience with MDR-TB patients in a mobile injection team at Ugu District, be an enrolled nurse registered with the South African Nursing Council as an enrolled nurse and must have an annual practicing certificate, or be a TB assistant, be willing to participate in the study and be located at the decentralised and satellite site. Data were collected through individual in-depth interviews with the participants. Data were analysed using Giorgi’s method of data analysis. The research findings revealed four broad themes (the perceptions held by the team, challenges, available support and needs to promote the service) and 73 sub-themes. The findings of the study indicate that the MDR-TB outreach injection teams experience many challenges in the community and need to be supported by their management in order to provide quality care to the patients. This study contributes to the development of guidelines to assist the mobile injection teams to provide quality patient care and effective service delivery. Based on the findings, the recommendation is that an intervention study be performed to compare the utilisation of the mobile MDR-TB injection team after implementing the recommendations made and the guidelines developed in this study / Health Studies / D. Litt. et Phil. (Health Studies)