In individuals with tuberculosis-infection – until recently referred to as latent tuberculosis infection – the risk of progression to active tuberculosis (reactivation) varies strongly. Among those... Show moreIn individuals with tuberculosis-infection – until recently referred to as latent tuberculosis infection – the risk of progression to active tuberculosis (reactivation) varies strongly. Among those at increased risk of reactivation are patients with an impaired immune system, e.g. due to immunosuppressive therapy. Therefore, prior to planned immunosuppression, patients are screened for tuberculosis-infection and subsequently treated in case of infection. Current screening methods include the Mantoux test, Interferon-γ release assays (i.e., the QuantiFERON-TB Gold Plus and T-SPOT.TB) and chest X-ray. However, despite screening, cases of reactivation continue to occur – in part due to the lack of a gold standard test for tuberculosis-infection. Therefore, the aims of this thesis were to increase the diagnostic sensitivity for tuberculosis-infection prior to immunosuppression. Using various (novel) methods we showed that approximately two-thirds of all QuantiFERON-TB Gold Plus results just below the manufacturer’s cut-off (in the borderline range) are caused by Mycobacterium tuberculosis-infection, which now warrants preventive treatment in patients with such a result. Furthermore, we quantified the diagnostic accuracy of chest X-ray for tuberculosis-infection and showed that using a novel ultra-low dose CT scanning technique, sensitivity for tuberculosis-infection could be significantly increased by three-fold compared to chest X-ray. 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 describes several topics on angiogenesis and screening in uveal melanoma, the most frequent eye tumour in adults. The expression of vascular endothelial growth factor and other... Show moreThis thesis describes several topics on angiogenesis and screening in uveal melanoma, the most frequent eye tumour in adults. The expression of vascular endothelial growth factor and other angiostimulating factors in this tumour are described. In a second part, the use of different screening tests in screening for metastases of uveal melanoma is investigated. Show less
