Academic Ceremonies September 2011

“Pulsing response of the cardiac transcriptome”

“Rural Nonfarm Employment and International Migration as Alternatives to Agricultural Employment; the case of Kyrgyzstan”

“When all eyes are on you; studies into threat processing and pharmacological treatment of social anxiety disorder”

Social anxiety disorder is a disabling psychiatric disorder characterised by an extreme fear of negative judgement by others. The disorder is often accompanied by other disorders, such as depression and alcoholism.  This thesis demonstrates that persons with a social anxiety disorder show dysfunctional processing of threatening information (such as angry faces).  Furthermore, persons with social anxiety thoughts turn out to be at a higher risk of developing paranoid thoughts later on, possibly especially when they use cannabis. Therefore, social anxiety as extra risk factor for paranoia should be added to the information that is used in the current psycho-educational programmes on drug use and psychiatric symptoms in Young people. Moreover, the thesis shows that medication treatment of the social anxiety disorder is far from satisfactory.

Key words:

Social anxiety disorder, information processing, medication, information

‘Climbing the Pyramid; towards understanding performance assessment’

The studies presented in the thesis show that hemolysis (the spread of red blood damage) plays an important role in the development of organ injury during cardiovascular surgery. The focus lays on disturbances in microcirculatory perfusion and induction of injury to the gut and kidneys during acute hemolysis. Therapeutic options, mainly the inhalation of nitric-oxide gas, to counteract the deleterious effects of hemolysis on microcirculatory blood flow and the development of organ injury are studied and discussed.

Key words:

hemolysis, cardiovascular surgery, organ injury

“Exploring the Influence of Contextual Factors of the Clinical Encounter on Clinical Reasoning Success”

Context specificity refers to the phenomenon that physician’s clinical reasoning performance (decision making) can vary from patient to patient. This thesis sought to unravel this phenomenon through exploring the influence of context on clinical reasoning performance. 
First, we define context and outline contemporary theory to explore this phenomenon.  Next, we found that selected contextual factors (patient, physician, practice) do influence experts’ clinical reasoning performance and we identify several potential mechanisms.  We then explored medical students’ clinical reasoning and found that the authenticity of instructional format did not significantly impact subsequent clinical reasoning performance. Finally, we explored functional neuroimaging correlates of clinical reasoning expertise and found evidence to support contemporary theory.  

Key words:

Clinical reasoning, context

“MRI of the therapeutic neovascularization: morphology & function”

For patients with leg and coronary artery stenosis treatments such as dotter and bypass operations are not always effective. Currently, research is conducted into stimulating the growth of new blood vessels that can repair the tissue blood circulation in these patients. To evaluate and steer the effectiveness of these therapies at an early stage non-invasive techniques are necessary. This dissertation describes MRI techniques that can image the new blood vessels and their influence on the tissue blood circulation. It also discusses solutions for the challenges that imaging the vessel growth involves. This is an important step in the evaluation of vessel growth therapy. 
This research was financed by the Nederlandse Hartstichting. 

Key words:

neovascularization, MRI, peripheral and coronary arterial disease

“Glaucoom. Druk, druk, druk…”

“Interactions in Psychosis; linking environment, brain and genes”

The mechanism behind the link between stress and psychosis is still not sufficiently known. This dissertation studies among others biological and genetic markers of stress sensitivity. In a subgroup of people with a psychotic disorder, increased stress sensitivity appears to be associated with a smaller hippocampus (a brain area that is involved in the storage of new memories) and with the ‘Met/Met genotype’ of the COMT gene. In people with increased psychosis vulnerability also a raised cortisol reaction to stress appears to be connected with subclinical psychotic experiences (subtle psychotic experiences, such as suspicion, which everyone has at times). 

Key words:

psychosis, stress, biologic markers

“Multi-modality imaging for treatment response evaluation in rectal cancer”

This dissertation studies the use of medical imaging, particularly Positron Emission Tomography (PET), for the evaluation of the treatment response in rectal cancer. Changes in various processes within the tumour were correlated with each other, but the correlation with pathological tumour regression was also studied.  
The results show that a precise prediction of the treatment response of the tumour is already possible at an early stage (two weeks after the start of the treatment) on the basis of PET imaging. The results also show that the delineation of the tumour (drawing of the tumour, distinguishing the tumour and the surrounding healthy tissue) does not necessarily have to be done manually by the radiotherapist-oncologist, because automatic and very precise tumour delineation is possible on the basis of PET imaging. The results presented in this dissertation are the first step towards patient specific treatment plans.

Key words:

rectal cancer, PET, treatment

“Essays in Matching with Money and Networks”

For a model in which any two agents can trade via bilateral contracts, assuming that their preferences satisfy some natural assumptions, we show that stable solutions can always be guaranteed to exist. Algorithms for finding one such stable solution are available. Applications may be possible in matching markets for couples and electricity markets.
Discussing the most prominent methods used for evaluating scientific output we show that they do not distinguish quality from quantity at article level. The systematic bias we find is analytically tractable and implies that the methods are manipulable. We introduce modified methods that correct for this bias.
The PhD was financed by NWO under grant VIDI-452-06-013

Key words:

bilateral contracts, algorithms, evaluation methods

“The road to adolescent traffic safety is paved with good intentions: Towards a theory- and evidence-based approach in traffic safety education”

“Poverty alleviation: Aid and social pensions”

“Heraclitische ethiek. Omgaan met de soft impacts van technologie.”

“Bestuurlijk gedonder”

In local administration in the Netherlands, mayors, aldermen or entire city councils are increasingly often forced to resign. In some communities this occurs so often that these communities have become known for the large amount of administrative problems that occur or have occurred.  This dissertation studies how many of these ‘administrative problem communities’ there are in the Netherlands, measured over the period 1998-2010, and what is the cause of the continuous problems. From a list of nine communities, four were investigated. The main conclusion is that in administrative problem communities a number of problem causing factors are assembled, while inhibitory factors (sometimes temporarily) are lacking.  Met name het ontbreken van goede communicatie in de coalitie jaagt problemen aan, terwijl de burgemeester juist remmend kan werken.

Key words:

administrative problem communities, causes

“Insulin resistance and mitochondrial function; a mitocentric view”

Results in this thesis show that patients with type 2 diabetes, as well as first-degree realatives of type 2 diabetic patients, have a lower capacity to burn fat and sugar. Mitochondria are the organelles where the burning of fat and sugar finds place. These mitochondria have a lower functionality in muscle of type 2 diabetic patients, which could lead to fat accumulation in the muscle and insulin resistance. These mitochondrial defects, however, restore upon a 12-week physical exercise-training programme. We also found that endurance trained men are better protected against the negative effects of fat on insulin sensitivity. We conclude that physical exercise is capable to restore compromised mitochondrial function in type 2 diabetes and that it has a protective role against fat accumulation and the development of insulin resistance. Mitochondrial function and insulin sensitivity are, however, not per se causally related, and are two independent mechanisms involved in the development of type 2 diabetes.

Key words:

type 2 diabetes, physical activity, mitochondria

“The role of arginine in human healing”

Accelerating wound healing is very important for patients with for example burns of chronic wounds. This dissertation studies the role of the amino acid arginine in this healing. Animal experiments show that arginine considerably accelerates wound healing in animals. The hypothesis was that human skin and wounds use arginine. The first part of the hypothesis was confirmed. Moreover, the results suggested that during normal human wound healing arginine is used. However, a study into the effect of arginine addition on wound healing (of surgical wounds) showed no positive effect.
This research was conducted with financial support from the Dutch Burns Foundation and the ‘Profileringsfonds’ of Maastricht University Medical Center.  

Key words:

wound healing, arginine

“Fysiologie als metafoor”

‘Venous cryo surgery of the leg’

The surgical treatment of varicose veins is one of the most performed interventions worldwide. Because of the enormous amount of operations this also involves considerable costs. Each improvement of technique can lower the risks of relapse and the costs and increase the quality of life. Historically, the surgeon ‘stripped’ the varicose vein from the leg by means of an operation. In the last ten years, the treatment has become increasingly less invasive and has for example been replaced by the laser treatment. An alternative treatment of the classic strip operation is the cryo strip surgery in which the vein is frozen out of the leg. 
This dissertation shows that this cryo strip is less effective than the classic strip surgery and should in fact no longer be used. It also turns out that the modern treatment of varicose veins by means of laser or other sources of heat is not better than the old strip surgery (that is even less expensive).  

Key words:

varicose veins, strip surgery, cryo strip, laser therapy

“The Metabolic Syndrome and Cardiovascular Disease: The CODAM study”

‘Surgical management of chronic inguinal pain syndromes’

“Interrupted Innovation; Emerging economies in the structure of the global aerospace industry”.

Key words:

aerospace manufacturing; latecomer industrialization; technological capabilities; sectoral systems of innovation

“Connecting the dots; functional networks and cognition in chronic epilepsy”

Aircraft and spacecraft manufacturing has been a privileged sector of leading industrialized economies because of its high technology and capital intensity. Statistical data on aerospace manufacturing compiled for the first time for nearly 50 countries and 50 years shows that only a few of the latecomers have succeeded in creating sustained growth in the sector. The study shows that competitive pressures and the cyclical nature of the industry require the establishment and periodical restructuring of sectoral innovation systems. The evolution of aerospace innovation systems are discussed in greater detail in the cases of Brazil, China, Argentina, Indonesia and Singapore.

“Hemolysis, microcirculatory changes and organ injury induced by cardiovascular surgery”

The studies presented in the thesis show that hemolysis (the spread of red blood damage) plays an important role in the development of organ injury during cardiovascular surgery. The focus lays on disturbances in microcirculatory perfusion and induction of injury to the gut and kidneys during acute hemolysis. Therapeutic options, mainly the inhalation of nitric-oxide gas, to counteract the deleterious effects of hemolysis on microcirculatory blood flow and the development of organ injury are studied and discussed.

Key words:

hemolysis, cardiovascular surgery, organ injury

“New developments in Sacral Neuromodulation for Lower Urinary Tract Dysfunction”

Function disorders of the bladder are a serious health problem. Globally it concerns patients with an overactive bladder (often combined with urine loss) and patients with a dysfunctional bladder evacuation. In the first instance treatment consists of pelvic floor therapy and medication. However, a large part of the patients insufficiently benefits from this or cannot stand the side-effects. Sacral neuromodulation is a relatively new treatment. The nerves of the bladder are stimulated with a subcutaneous stimulator, which helps the patients gain control over their bladder again. This dissertation shows that this treatment is safe and long term effective. After approximately 5 years the treatment is successful in 64 % of the patients.  

Key words:

bladder, function disorders, sacral neuromodulation