This Thesis aims at the development of novel subunit selective inhibitors of the proteasome. -Three vinyl sulfone analogues of three epoxyketone containing inhibitors described in literature are... Show moreThis Thesis aims at the development of novel subunit selective inhibitors of the proteasome. -Three vinyl sulfone analogues of three epoxyketone containing inhibitors described in literature are synthesised and characterised. The nature of the electrophile determines subunit selectivity of the inhibitor. -Ten Michael acceptors are coupled to three peptoid tails yielding thirty peptide-like compounds. None of the peptoid Michael acceptors are efficient proteasome inhibitors. Using the Staudinger-Bertozzi ligation followed by affinity purification, tryptic digestion of the isolated proteins and LC/MS/MS identification, the targets of two compounds in HEK293T and RAW264.7 cells are determined. -Syringolins are potent proteasome inhibitors found in nature. A syringolin structural motif was built in peptoid epoxyketones and vinyl sulfones yielding a 16-membered library of proteasome inhibitors. The distance between the urea and electrophile dictates subunit selectivity. -Three cyclooctynes are compared to the Staudinger-Bertozzi two-step labelling strategy. Cyclooctynes quantitatively convert azide labelled proteasomes at a lower concentration than the Staudinger-Bertozzi phosphane but cyclooctyne two-step labelling is associated with tremendous background labelling. -A library of peptoid vinyl sulfones with basic amino acid side chains is synthesised. A compound with two benzylamine residues is a potent and _2 selective proteasome inhibitor. Attachment of a BODIPY fluorophore yielded a _2 selective probe. Show less
The main goal of this thesis is to investigate the possible factors playing a role in dilatation of the neo-aortic root in patients after ASO for TGA. Basic histological research as well as... Show moreThe main goal of this thesis is to investigate the possible factors playing a role in dilatation of the neo-aortic root in patients after ASO for TGA. Basic histological research as well as histological 3D reconstruction of the arterial roots has been combined with clinical investigation. The studies that resulted from this research form the basis of this thesis. We went __back to the roots__. Show less
Spiking neural P systems are a class of distributed and parallel computing models inspired by the neurophysiological behavior of neurons sending electrical impulses (spikes) along axons to other... Show moreSpiking neural P systems are a class of distributed and parallel computing models inspired by the neurophysiological behavior of neurons sending electrical impulses (spikes) along axons to other neurons. In this thesis, we consider that the spiking neural P systems are universal even if the systems work in limited asynchronous mode. And we also investigated different variants of spiking neural P systems with other additional features, such as the axon functioning, the growth of dendritic trees in neurons, the positive or negative weights on synapses, and the astrocytes having excitatory and inhibitory influence on synapses. Show less
Improving survival rates in children and adolescents with malignant bone tumours, paved the way to the application of new surgical extremity-salvage techniques. For the surgical treatment of... Show moreImproving survival rates in children and adolescents with malignant bone tumours, paved the way to the application of new surgical extremity-salvage techniques. For the surgical treatment of malignant bone tumours of the lower extremity, there are a number of resection options (amputation, limb sparing, and rotationplasty) available. Each option has its own indication and after the surgery different advantages and disadvantages. The debate is whether limb-salvage or ablative surgery is advantageous for the individual patient. Purpose of the studies presented in this thesis are evaluate and compare QoL, functional ability and physical activity levels among children and young adults in the first years after bone cancer surgery of the leg. A cross sectional and a prospective study were conducted in the Dutch university bone cancer centres. The results of the cross-sectional study show that outcomes are equivalent for those undergoing limb salvage or ablative surgery. The results of the prospective study showed that; survivors improve in the two years following resection of the bone tumour and the resulting limb-sparing or ablative surgery at all domains evaluated, with the exception of the mental QoL domains. These improvements were most pronounced over the first year after surgery. Show less
Major advances have been made in the treatment of rheumatoid arthritis, a potentially chronic disabling disease which poses a large burden on both patients and society. By early start of disease... Show moreMajor advances have been made in the treatment of rheumatoid arthritis, a potentially chronic disabling disease which poses a large burden on both patients and society. By early start of disease-modifying antirheumatic drugs, including methotrexate as a prominent drug, the use of combination therapies including prednisone or biologicals, and tight control of disease activity, many patients are able to reach a state of clinical remission and some can even taper and stop antirheumatic therapy. Challenges lie in correctly identifying the earliest manifestations of the disease, starting the right treatment sufficiently early, tailored to the individual patient, and setting the optimal treatment goal at which to steer therapy adjustments. This thesis has made a start towards tackling several of these challenges and discusses further necessary steps that may lead to a fundamental change in the outlook of patients with rheumatoid arthritis. Show less
Technological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in... Show moreTechnological innovation has helped the zebrafish embryo gain ground as a disease model and an assay system for drug screening. Here, we review the use of zebrafish embryos and early larvae in applied biomedical research, using selected cases. We look at the use of zebrafish embryos as disease models, taking fetal alcohol syndrome and tuberculosis as examples. We discuss advances in imaging, in culture techniques (including microfluidics), and in drug delivery (including new techniques for the robotic injection of compounds into the egg). The use of zebrafish embryos in early stages of drug safety-screening is discussed. So too are the new behavioral assays that are being adapted from rodent research for use in zebrafish embryos, and which may become relevant in validating the effects of neuroactive compounds such as anxiolytics and antidepressants. Readouts, such as morphological screening and cardiac function, are examined. There are several drawbacks in the zebrafish model. One is its very rapid development, which means that screening with zebrafish is analogous to __screening on a run-away train.__ Therefore, we argue that zebrafish embryos need to be precisely staged when used in acute assays, so as to ensure a consistent window of developmental exposure. We believe that zebrafish embryo screens can be used in the pre-regulatory phases of drug development, although more validation studies are needed to overcome industry scepticism. Finally, the zebrafish poses no challenge to the position of rodent models: it is complementary to them, especially in early stages of drug research. Show less
This thesis describes the PROMODE-study, which investigated in a pragmatic way whether a pro-active approach in primary care by screening for depressive symptoms, followed by an intervention offer... Show moreThis thesis describes the PROMODE-study, which investigated in a pragmatic way whether a pro-active approach in primary care by screening for depressive symptoms, followed by an intervention offer to persons of 75 years and over who screened positive, is (cost)effective to detect and relieve suffering from depressive symptoms at old age. We compared two screening methods regarding yield and costs. Furthermore, we found that scores of the 15-item Geriatric Depression Scale were higher when this screening questionnaire was self-administered than when interviewer-administered. In our intervention study, a cluster-randomised controlled trial, we found that the stepped-care intervention program was not (cost)effective compared with usual care in general practice, possibly due to a low uptake of the offered course being the main part of the intervention. In a qualitative study we explored the limiting and motivating factors for accepting course participation. This revealed that most persons were not (yet) prepared to accept the unsolicited intervention offer, although perceived needs to relieve depressive symptoms seemed to largely match the elements of the course. It is discussed that a more selective approach, aimed at high risk-groups and focussing on need for and readiness to accept help, might increase efficiency of a combined screening-intervention program. Show less
This thesis explores the resistance of tomato plants to WFT. At first an overview about tomato, WFT and their interactions is presented (this chapter). This is followed by 5 experimental chapters.... Show moreThis thesis explores the resistance of tomato plants to WFT. At first an overview about tomato, WFT and their interactions is presented (this chapter). This is followed by 5 experimental chapters. The first experiment comprises a comparison of thrips resistance between major tomato cultivars and wild tomatoes. Wild species of crops are important sources of genes for resistance to biotic and abiotic stresses. In this study, we explored the natural variation in WFT resistance of the genus Lycopersicon by performing bioassays and comparing thrips damage on some wild species and cultivated lines to determine the chemical and mechanical resistance factors in these plants. All plants were subjected to NMR metabolomic analysis to correlate thrips resistance to plant secondary metabolites (Chapter 2). Invasion of pests may lead to rapid local adaptation and the development of biotypes specialized to different hosts. Therefore, host plant adaptation of thrips was studied by observing variation in genetics and performance of Dutch WFT populations (Chapter 3). In this chapter genetic differences between Dutch WFT populations collected on different hosts were analysed with AFLP and the existence of possible cryptic species was tested using mitochondrial barcoding. Feeding damage and reproduction of thrips were examined in different thrips bioassays. A negative effect of CGA in chrysanthemum on WFT has been reported earlier. To study the effects of CGA level in tomato on thrips resistance, transgenic tomatoes with increased amounts of CGA were subjected to thrips infestation and feeding damage was monitored (Chapter 4). Introgression lines (ILs), represent an excellent platform to explore the genetics of multiple biological and chemical traits of agronomical importance. The wild tomato, S. pennellii was highly resistance to WFT (Chapter 2). A set of 76 introgression lines between the S. pennellii and the cultivated tomato S. lycopersicum was used to detect QTLs associated with WFT resistance, secondary metabolites and their co-localization (Chapter 5). Sugars have acted as plant hormones that control gene expression and development processes in plants and sugar spraying of leaves has been used in pest management of different plants. Potentially, it can, therefore be used as a new and more environmentally friendly method of crop protection. We used sugar-sensing, applying sprays of sucrose, fructose and glucose to increase resistance to WFT in a susceptible tomato cultivar (Chapter 6). The summary and conclusions of this thesis are given in chapter 7. Show less
Several years ago we embarked on a journey, aiming to identify the molecular mechanisms of candidate risk genes for type 1 diabetes (T1D), focusing on their role in disease pathogenesis. In this... Show moreSeveral years ago we embarked on a journey, aiming to identify the molecular mechanisms of candidate risk genes for type 1 diabetes (T1D), focusing on their role in disease pathogenesis. In this context, we studied phenomena of T1D with clinical relevance in great detail and aimed to find genetic correlates of these. This thesis can be considered the clinical chapter of this journey providing validation and extension of several clinically relevant gene polymorphisms with functional consequences in relation to growth (INS-VNTR, IGF1, disease progression and remission (IFN-_, IL-10,), islet autoimmunity (INS-VNTR), and environment (Lewis). We found: Increased early growth, rather than birth weight, to be a risk factor for T1D; Accelerated growth preceding T1D is limited to early life i.e. to the 1st year of life ; Early in life and in contrast to the INS-VNTR, an IGF-1 variant is associated with T1D via accelerated growth ; Remission or disease progression is at least partially immune-mediated ; IFN-_ levels, along with their corresponding genotypes, could be valuable in predicting (partial) clinical remission at clinical onset of diabetes ; T1D disease mechanisms appear to overrule genetic influences in disease progression. Show less
Chapter 1 reviews technical developments of cardiac CT and current status, recommendations and future perspective of various clinical cardiac CT applications. In chapter 2, the eff ect of dose... Show moreChapter 1 reviews technical developments of cardiac CT and current status, recommendations and future perspective of various clinical cardiac CT applications. In chapter 2, the eff ect of dose reduction on diagnostic performance in CT coronary angiography is assessed. Chapter 3 evaluates the eff ect of thin-slice image reconstructions on coronary artery calcium measurements. In chapter 4, the assessment of Agatston scores using coronary CT angiography is studied. Chapter 5 evaluates the predictive value of CT-derived RV/LV ratios and cardiac biomarkers for short term clinical outcome in patients with suspected acute PE. In chapter 6, the incremental value of ventricular function with ECG-synchronized cardiac CT over standard pulmonary CTA-derived RV/LV ratios for predicting clinical outcome in patients with suspected acute PE is discussed. Chapter 7 studies the influence of timing of NT-pro-BNP sampling for predicting adverse clinical outcome. Show less
CADASIL is a hereditary cerebral small vessel disease, caused by a mutation in the NOTCH3 gene, leading to migraine with aura, cerebrovascular accidents and cognitive decline at young to middle... Show moreCADASIL is a hereditary cerebral small vessel disease, caused by a mutation in the NOTCH3 gene, leading to migraine with aura, cerebrovascular accidents and cognitive decline at young to middle adult age. MRI scans of the brain may show lacunar infarcts, white matter lesions and microbleeds. In this thesis MRI scans of the brains are used to investigate the disease course in CADASIL. It is shown that lacunar infarcts, white matter lesions and microbleeds are progressive in CADASIL patients. Vascular risk factors are not associated with rate of progression of these MRI abnormalities. However, the rate of disease progression can be predicted by measuring the amount of MRI abnormalities at baseline. Lacunar infarcts, microbleeds and increased white ventricular volume are strongly associated with cognitive decline in CADASIL. Progression of white matter hyperintensities can be predicted by measurements of cerebrovascular reactivity. Using high-field MRI we demonstrated that luminal diameters of lenticulostriate arteries are normal in CADASIL, and that lacunar infarcts in CADASIL are not the result of luminal narrowing of these vessels. High-field MRI also showed that CADASIL patients have an increased diffuse iron deposition in the putamen and caudate nucleus of the brain. Show less
Cells in the human body have to deal with DNA damage daily, either caused by external or internal sources. The DDR is particularly strong in stem cells. Since these cells have a long life span and... Show moreCells in the human body have to deal with DNA damage daily, either caused by external or internal sources. The DDR is particularly strong in stem cells. Since these cells have a long life span and are essential for tissue homeostasis, tolerance to damaged DNA would lead to accumulation of mutations and malignant transformation. In addition, accumulation of damaged DNA would lead to loss of the stem cell pool and contribute to aging. In this thesis I investigated the role of the DNA damage response in the context of stem cells as well as cancer cells, from the response to different DNA damaging agents, to the importance of the interaction with the extracellular matrix in combination with the presence of oncogenes. In order to acquire a complete picture of the DNA damage response in mES cells, and therefore elucidate novel pathways involved in this particular response, we combined OMICS techniques such as Functional Genomics, Transcriptomics and Phosphoprotoemics, that once overlapped, allowed us to find novel pathways that where not previously described to be involved in the DNA damage response. Show less
The work presented in this thesis concerns various, mainly clinicopathological, studies of ANCA-associated vasculitis. The first chapter provides a general introduction to the topic and the studies... Show moreThe work presented in this thesis concerns various, mainly clinicopathological, studies of ANCA-associated vasculitis. The first chapter provides a general introduction to the topic and the studies. Chapters 2 and 3 describe long-term patient and renal survival data concerning 535 patients. The emphasis in these chapters is on the results of multivariable models, developed to detect baseline patient characteristics that can provide reliable prognostic information to treating physicians. Chapter 4 comprises a clinicopathological study performed on renal biopsies of patients experimentally treated with a rituximab-based regimen. Specific attention is paid to the presence of B cell, T cell and plasma cell infiltrates in the diagnostic renal biopsy and the relation of these infiltrates to renal outcome under rituximab treatment. Chapter 5 reviews known disturbances in cellular immunity in vasculitis. In chapter 6 the presence of anti-plasminogen antibodies is described in two independent patient cohorts, one from the United Kingdom and one from the Netherlands. Chapter 7 illustrates that a simple classification schema comprising only four histological classes correlates well with renal outcome in a first validation exercise. Finally, the results described in this thesis are summarized and discussed in chapter 8. Show less
We described a total of 4 species and 4 subspecies of Coelogyne and one species of Panisea from the Himalayan region as new species to science based on analysis of morphological characters and DNA... Show moreWe described a total of 4 species and 4 subspecies of Coelogyne and one species of Panisea from the Himalayan region as new species to science based on analysis of morphological characters and DNA sequences. Extrafloral nectar produced by Nepalese Coelogyninae was found to play a key role in attracting aggressive ants protecting flowers and leaves against herbivorous beetles. This nectar was found to be exudated by nectary-modified stomata positioned just below the pedicels on the inflorescence. Our ethnobotanical survey showed that a total of 60 species of wild orchids were found to be used as energizers, aphrodisiacs and treatments of burnt skin, fractured or dislocated bones, headaches, fever and wounds. The antibacterial screening carried out by us indicated that the majority of the medicinal orchid species used by local people in Nepal showed biological activity. A total of 10% of confiscated orchids remained sterile but could be identified to species level by applying DNA barcoding and chemical profiling. Our market surveys in central Nepal showed that many wild orchid species are involved in illegal trade and exported to China and India for preparation of herbal products and traditional Chinese medicines. Wild orchids were found to be immensely important to sustain local livelihoods in Nepal. Due to large scale ille_gal trade, many species are rapidly becoming endangered in the wild. Establishing sustainable orchid breeding enterprises could be a valuable alternative for the production of medicinal orchids for local communities. Critically endangered species should be placed on CITES Appendix I to prevent their extinc_tion from the wild. DNA barcoding and chemical profiling seem promising tools for a better control of cross-border illegal trade. Show less
This thesis describes the epidemiology of emerging infections with Clostridium difficile. Outbreaks of severe disease with high mortality were found to be associated with certain types of this... Show moreThis thesis describes the epidemiology of emerging infections with Clostridium difficile. Outbreaks of severe disease with high mortality were found to be associated with certain types of this bacterium and type specific risk factors were identified. Moreover, highly discriminatory typing techniques were useful in understanding clonal disseminations across healthcare institutions. Show less
The main aim of this thesis is to evaluate the clinical risk factors and imaging techniques for the diagnosis and to analyze the treatment outcomes of Ruthenium-106 plaque brachytherapy for iris... Show moreThe main aim of this thesis is to evaluate the clinical risk factors and imaging techniques for the diagnosis and to analyze the treatment outcomes of Ruthenium-106 plaque brachytherapy for iris and iridociliary melanomas in terms of tumor regression and its complications, survival and development of metastasis. This thesis also focuses on the differential diagnosis of iris melanomas. Understanding of these subjects can assist ophthalmologists in the diagnosis and evidence-based management of iris melanomas, therefore avoiding unnecessary treatment of an iris naevus. Show less
Rheumatoid arthritis (RA) is a complex chronic disease, which, despite the advanced pharmacological treatment, requires care provided by health professionals other than the rheumatologist in many... Show moreRheumatoid arthritis (RA) is a complex chronic disease, which, despite the advanced pharmacological treatment, requires care provided by health professionals other than the rheumatologist in many patients during the course of their disease. Physical therapy is an important part of the non-pharmacological treatment of patients with RA. However, due to the changes in the medical treatment of patients with RA the role of physical therapists and patient has changed as well. The aims of the present thesis were to describe the currently available RA guideline including recommendations concerning the physical therapy management, to develop a RA guideline specific for physical therapists, and make an inventory of the currently provided physical therapy management in patients with RA. Moreover, this thesis includes a synthesis of the evidence regarding the effectiveness and safety of supervised and home-based exercise programs in patients with RA and the maintenance of physical activity after two one-year internet-based physical activity interventions in RA patients. In addition, the role of motivation and health care providers__ practice regarding the level of physical activity of patients with RA was evaluated. Show less
The basis of the presented investigations in this thesis is the modulation of signal inducers and their respective activated signaling cascades through intrinsic antagonistic feedback- and/or feed... Show moreThe basis of the presented investigations in this thesis is the modulation of signal inducers and their respective activated signaling cascades through intrinsic antagonistic feedback- and/or feed forward-loops. In particular, signal inducers of the transforming growth factor-_ superfamily were investigated on their impact on tissue development and maintenance. Thereby, the main focus lies on a group of proteins that are known as bone morphogenetic proteins (BMPs). Due to their wide impact, Dr. H. Reddi recently proposed a more suitable name to this cytokines: body morphogenetic proteins. The distinct terminology is also reflected in this book. Not only does this book discuss the impact of BMP signal modulation on osteoblast differentiation, it also focuses on BMPs as potential inducers of signaling drifts in fibrotic traits. Interestingly, BMPs can relay signals with different outcomes. They can be signal triggers themselves as investigated in the case of osteoblast differentiation, but they can also arrest signaling cascades, as shown for TGF-_ induced fibrosis. Up to date, more than fifteen different BMPs are known. One aim of this book is to biochemically characterize different BMPs on their potential to relay signals and how this signals can be governed to yield a specific medical benefit. It is well known that BMPs are tightly regulated on diverse interfaces throughout the cell. Thereby, the presented investigations focus on innate extracellular signaling modulators, as well as on synthetic small molecule inhibitors that have the potential to facilitate the development of new treatment strategies of certain human diseases. Show less
This thesis evaluates, using various methods, two important surgical procedures currently used in heart failure patients: surgical ventricular restoration and restrictive mitral annuloplasty. The... Show moreThis thesis evaluates, using various methods, two important surgical procedures currently used in heart failure patients: surgical ventricular restoration and restrictive mitral annuloplasty. The conductance catheter was used to analyze the hemodynamic effects of heart failure surgery invasively. It demonstrated improvement in systolic function of the left ventricle for both procedures at long term follow-up. Diastolic function demonstrated signs of impairment, although the functional effect remained limited, regarding limited or no increase in left ventricular end-diastolic pressure for SVR and RMA, respectively. Furthermore, assessment of left ventricular volumes demonstrated persistent reverse remodeling at follow-up. Clinical performance demonstrated significant improvement for both surgical procedures. The hemodynamic results together with the positive clinical outcome for both surgical procedures supports the use of these procedures in end-stage heart failure patients. Regarding the fact that using the conductance catheter is time consuming and can be burdensome for patients, a demand for less invasive methods was generated. Evaluation of alternative methods demonstrated that heart failure surgery can also be evaluated by single-beat analysis, a simplified method of the conventional conductance catheter method avoiding load interventions by temporary vena cava occlusions. Furthermore, echocardiography and to a certain extent, serum biomarker analysis can also be used. Show less
Stem cell-based therapies represent promising approaches for the treatment of incurable diseases and tissue injury due to the capacity of these cells to self-renew and differentiate into... Show moreStem cell-based therapies represent promising approaches for the treatment of incurable diseases and tissue injury due to the capacity of these cells to self-renew and differentiate into specialized mature cells. Understanding the interaction of stem cells with the disease/injured environment and their contribution to the repair process by release of regeneration-promoting signals or by differentiation into the lost cell types is crucial for the advancement of their clinical application. This thesis focuses on one stem cell population, the mesenchymal stem cells (MSCs) from human and in particular on their role and utility in skeletal muscle regeneration. For this purpose, several in vivo tissue damage models were employed (i.e. cardiotoxin-induced injury, pressure ulcers, and subcutaneous implants of minced skeletal muscle). Most of the experiments were performed in immunocompromised mice (i.e. NOD/SCID) to avoid immunological rejection of the human cells. Furthermore, we described the downregulation of MHC class I protein expression on the surface of human MSCs by retroviral vectors encoding a herpesviral immunoevasin (i.e. the US11). This renders human MSCs vulnerable to NK cell recognition and cytolysis implies that multiple viral immune evasion proteins are likely required to make human MSCs non-immunogenic and thereby universally transplantable. Show less
