Anal intraepithelial neoplasia in HIV+ men:Epidemiology, cancer risk stratification and prevention of recurrences

Anal cancer is relatively rare in the general population, but incidence rates have been steadily increasing over the past decades. In specific risk groups, most importantly human immunodeficiency virus-positive (HIV+) men who have sex with men (MSM), the burden of anal cancer is disproportionally high. Anal cancer is caused by a persistent human papillomavirus (HPV) infection. Anal precancerous lesions called high-grade anal intraepithelial neoplasia (HGAIN) are highly prevalent in HIV+ MSM. Therefore, preventing development of cancer from precancerous lesions through screening for and treatment of HGAIN in this risk group is under debate. However, current screening procedures are suboptimal. In this thesis, we increased the understanding of the epidemiology of anal cancer in general and within high-risk populations in particular. Next, we investigated several novel and promising strategies to overcome drawbacks of current screening. In particular, we examined biomarkers for cancer risk stratification of HGAIN to identify lesions with a high risk of progression to cancer, allowing a more targeted treatment approach, thereby preventing overtreatment of lesions with a low risk of progression. We evaluated biomarkers based on host cell DNA methylation as well as immunohistochemical markers applicable on anal tissue samples. In the last part of this thesis we evaluated the efficacy of HPV vaccination to prevent recurrences of HGAIN in HIV+ MSM. This work will help improve the effectiveness of anal cancer screening and quality of life of people at risk for anal cancer

Droge duinvegetatie zeer zuinig met water

Over de gevolgen van droogte voor de soortensamenstelling en de verdamping van grondwateronafhankelijke duinvegetaties is heel weinig bekend. Op basis van verkennend onderzoek verwachten we dat meer droogte in de zomer leidt tot een toename van het aandeel mossen en kale grond. Daardoor daalt de verdamping en neemt de winderosie toe. Klimaatverandering zou zo gunstig kunnen uitpakken voor zowel de noodzakelijke dynamiek in het duin, als voor de aanvulling van de ondergrond met neerslagwate

Anal intraepithelial neoplasia in HIV+ men: Epidemiology, cancer risk stratification and prevention of recurrences

Anal cancer is relatively rare in the general population, but incidence rates have been steadily increasing over the past decades. In specific risk groups, most importantly human immunodeficiency virus-positive (HIV+) men who have sex with men (MSM), the burden of anal cancer is disproportionally high. Anal cancer is caused by a persistent human papillomavirus (HPV) infection. Anal precancerous lesions called high-grade anal intraepithelial neoplasia (HGAIN) are highly prevalent in HIV+ MSM. Therefore, preventing development of cancer from precancerous lesions through screening for and treatment of HGAIN in this risk group is under debate. However, current screening procedures are suboptimal. In this thesis, we increased the understanding of the epidemiology of anal cancer in general and within high-risk populations in particular. Next, we investigated several novel and promising strategies to overcome drawbacks of current screening. In particular, we examined biomarkers for cancer risk stratification of HGAIN to identify lesions with a high risk of progression to cancer, allowing a more targeted treatment approach, thereby preventing overtreatment of lesions with a low risk of progression. We evaluated biomarkers based on host cell DNA methylation as well as immunohistochemical markers applicable on anal tissue samples. In the last part of this thesis we evaluated the efficacy of HPV vaccination to prevent recurrences of HGAIN in HIV+ MSM. This work will help improve the effectiveness of anal cancer screening and quality of life of people at risk for anal cancer

Quantifying energy and water fluxes in dry dune ecosystems of the Netherlands

Coastal and inland dunes provide various ecosystem services that are related to groundwater, such as drinking water production and biodiversity. To manage groundwater in a sustainable manner, knowledge of actual evapotranspiration (<i>ET</i>_a) for the various land covers in dunes is essential. Aiming at improving the parameterization of dune vegetation in hydro-meteorological models, this study explores the magnitude of energy and water fluxes in an inland dune ecosystem in the Netherlands. Hydro-meteorological measurements were used to parameterize the Penman–Monteith evapotranspiration model for four different surfaces: bare sand, moss, grass and heather. We found that the net longwave radiation (<i>R</i>_nl) was the largest energy flux for most surfaces during daytime. However, modelling this flux by a calibrated FAO-56 <i>R</i>_nl model for each surface and for hourly time steps was unsuccessful. Our <i>R</i>_nl model, with a novel sub-model using solar elevation angle and air temperature to describe the diurnal pattern in radiative surface temperature, improved <i>R</i>_nl simulations considerably. Model simulations of evaporation from moss surfaces showed that the modulating effect of mosses on the water balance is species dependent. We demonstrate that dense moss carpets (<i>Campylopus introflexus</i>) evaporate more (5%, +14 mm) than bare sand (total of 258 mm in 2013), while more open structured mosses (<i>Hypnum cupressiforme</i>) evaporate less (−30%, −76 mm) than bare sand. Additionally, we found that a drought event in the summer of 2013 showed a pronounced delayed signal on lysimeter measurements of <i>ET</i>_a for the grass and heather surfaces respectively. Due to the desiccation of leaves after the drought event, and their feedback on the parameters of the Penman–Monteith equation, the potential evapotranspiration in the year 2013 dropped with 9% (−37mm) and 10% (−61 mm) for the grass and heather surfaces respectively, which subsequently led to lowered <i>ET</i>_a of 8% (−29 mm) and 7% (−29 mm). These feedbacks are of importance to water resources, especially during a changing climate with increasing number of drought days. Therefore, such feedbacks need to be integrated into a coupled plant physiological and hydro-meteorological model to accurately simulate <i>ET</i>_a. In addition, our study showed that groundwater recharge in dunes can be increased considerably by promoting moss vegetation, especially of open structured moss species

Immune function of the serosa in hemimetabolous insect eggs

Insects comprise more than a million species and many authors have attempted to explain this success by evolutionary innovations. A much overlooked evolutionary novelty of insects is the serosa, an extraembryonic epithelium around the yolk and embryo. We have shown previously that this epithelium provides innate immune protection to eggs of the beetle Tribolium castaneum. It remained elusive, however, whether this immune competence evolved in the Tribolium lineage or is ancestral to all insects. Here, we expand our studies to two hemimetabolous insects, the bug Oncopeltus fasciatus and the swarming grasshopper Locusta migratoria. For Oncopeltus, RNA sequencing reveals an extensive response upon infection, including the massive upregulation of antimicrobial peptides (AMPs). We demonstrate antimicrobial activity of these peptides using in vitro bacterial growth assays and describe two novel AMP families called Serosins and Ovicins. For both insects, quantitative polymerase chain reaction shows immune competence of the eggs when the serosa is present, and in situ hybridizations demonstrate that immune gene expression is localized in the serosa. This first evidence from hemimetabolous insect eggs suggests that immune competence is an ancestral property of the serosa. The evolutionary origin of the serosa with its immune function might have facilitated the spectacular radiation of the insects. This article is part of the theme issue 'Extraembryonic tissues: exploring concepts, definitions and functions across the animal kingdom'.Animal science

Preferential flow of bromide, bentazon, and imidacloprid in a Dutch clay soil

Leaching to ground water and tile drains are important parts of the environmental assessment of pesticides. The aims of the present study were to (i) assess the significance of preferential flow for pesticide leaching under realistic worst-case conditions for Dutch agriculture (soil profile with thick clay layer and high rainfall) and (ii) collect a high-quality data set that is suitable for testing pesticide leaching models. The movement of water, bromide, and the pesticides bentazon [3-isopropyl-1H-2, 1,3-benzothiadiazine-4(3H)-one-2,2-dioxide] and imidacloprid [1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine] was monitored in a clay soil for about 1 yr. The 1.2-ha field was located in the central part of the Netherlands (51°53' N, 5°43' E). The soil was a Eutric Fluvisol cropped with winter wheat (Triticum aestivum L.). Tile drains were present at a 0.8- to 0.9-m depth and the ground water level fluctuated between a 0.5- and 2-m depth. All chemicals were applied in spring. None of the soil concentration profiles showed bimodal concentration distributions. However, for each substance the highest concentration in drain water was found in the first drainage event after its application, which indicates preferential flow. This preferential flow is probably caused by permanent macropores that were present in the 0.3- to 1.0-m layer. At the time of the first drainage event, the drain water concentration of each substance was about an order of magnitude higher than its ground water concentration. Thus, the flux concentrations in drain water proved to be a more sensitive detector of preferential flow than the resident concentrations in the soil profile and the ground water

Testing MACRO (version 5.1) for pesticide leaching in a Dutch clay soil

Testing of pesticide leaching models against comprehensive field-scale measurements is necessary to increase confidence in their predictive ability when used as regulatory tools. Version 5.1 of the MACRO model was tested against measurements of water flow and the behaviour of bromide, bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one-2,2-dioxide] and imidacloprid [1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] in a cracked clay soil. In keeping with EU (FOCUS) procedures, the model was first calibrated against the measured moisture profiles and bromide concentrations in soil and in drain water. Uncalibrated pesticide simulations based on laboratory measurements of sorption and degradation were then compared with field data on the leaching of bentazone and imidacloprid. Calibrated parameter values indicated that a high degree of physical non-equilibrium (i.e. strong macropore flow) was necessary to describe solute transport in this soil. Comparison of measured and simulated bentazone concentration profiles revealed that the bulk of the bentazone movement in this soil was underestimated by MACRO. Nevertheless, the model simulated the dynamics of the bentazone breakthrough in drain water rather well and, in particular, accurately simulated the timing and the concentration level of the early bentazone breakthrough in drain water. The imidacloprid concentration profiles and its persistence in soil were simulated well. Moreover, the timing of the early imidacloprid breakthrough in the drain water was simulated well, although the simulated concentrations were about 2-3 times larger than measured. Deep groundwater concentrations for all substances were underestimated by MACRO, although it simulated concentrations in the shallow groundwater reasonably well. It is concluded that, in the context of ecotoxicological risk assessments for surface water, MACRO can give reasonably good simulations of pesticide concentrations in water draining from cracking clay soils, but that prior calibration against hydrologic and tracer data is desirable to reduce uncertainty and improve accuracy

Unsaturated hydraulic properties of xerophilous mosses: towards implementation of moss covered soils in hydrological models

Evaporation from mosses and lichens can form a major component of the water balance, especially in ecosystems where mosses and lichens often grow abundantly, such as tundra, deserts and bogs. To facilitate moss representation in hydrological models, we parameterized the unsaturated hydraulic properties of mosses and lichens such that the capillary water flow through moss and lichen material during evaporation could be assessed. We derived the Mualem-van Genuchten parameters of the drying retention and the hydraulic conductivity functions of four xerophilous moss species and one lichen species. The shape parameters of the retention functions (2.17<n<2.35 and 0.08<α<0.13c