296 research outputs found

    Maternal Quality of Life, Lifestyle, and Interventions after Complicated Pregnancies

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    Although most pregnancies elapse uneventful, complications arise in a substantial number. This thesis will focus on preeclampsia, intrauterine growth restriction and gestational diabetes, because women who experience these pregnancy complications share an increased cardiovascular and metabolic risk. See Box 1 for the definitions of these pregnancy complications used in this thesis

    Psychosocial determinants of lifestyle change after a cancer diagnosis:A systematic review of the literature

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    The aim of this study is to provide a systematic overview of the scientific literature on sociodemographic, psychological and social determinants that may facilitate or hamper lifestyle change after the diagnosis cancer. Four databases (PubMed, PsychINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science) were searched for relevant papers up to October 2021. Of the 9586 references yielded by the literature search, 123 papers were included: 71 quantitative and 52 qualitative papers. Findings showed a large variety of determinants influencing lifestyle change after cancer diagnosis, with differences between lifestyle behaviors (physical activity, diet, smoking, alcohol, sun protection, and multiple lifestyle behaviors) and findings from quantitative vs. qualitative studies. Findings demonstrate the important role of oncology healthcare professionals in promoting healthy lifestyle changes in cancer survivors. In addition, findings inform researchers involved in the development of health promotion programs about the methods and strategies they can use to promote healthy lifestyle changes in cancer survivors. Favorable lifestyle changes are expected to have beneficial effects on cancer risk and overall health in cancer survivors

    Amino acid modulation of lifespan and reproduction in Drosophila

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    Manipulating amino acid (AA) intake in Drosophila can profoundly affect lifespan and reproduction. Remarkably, AA manipulation can uncouple the commonly observed trade-off between these traits. This finding seems to challenge the idea that this trade- off is due to competitive resource allocation, but here we argue that this view might be too simplistic. We also discuss the mechanisms of the AA response, mediated by the IIS/TOR and GCN2 pathways. Elucidating how these pathways respond to specific AA will likely yield important insights into how AA modulate the reproduction-lifespan relationship. The Drosophila model offers powerful genetic tools, combined with options for precise diet manipulation, to address these fundamental questions

    Natural variation in memory formation among Nasonia parasitic wasps : from genes to behaviour

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    The ability to learn and form memory has been demonstrated in various animal species, ranging from relatively simple invertebrates, such as snails and insects, to more complex vertebrate species, including birds and mammals. The opportunity to acquire new skills or to adapt behaviour through learning is an obvious benefit. However, memory formation is also costly: it can be maladaptive when unreliable associations are formed and the process of memory formation can be energetically costly. The balance between costs and benefits determines if learning and memory formation are beneficial to an animal or not. Variation in learning abilities and memory formation between species is thought to reflect species-specific differences in ecology. This thesis focused on variation in the number of trials required to form long-term memory (LTM). LTM is considered the most stable and durable type of memory, but also the most costly, because it requires protein synthesis. Many animal species require multiple learning experiences, which are spaced in time, to form LTM. This allows re-evaluation of information before an animal invests in costly LTM. There is, however, variation in the number of trials that animal species require to induce LTM formation. A number of insect species, including a number of parasitic wasp species, form LTM after only a single learning experience. Parasitic wasps can learn odours that guide them towards suitable hosts for their offspring, so-called oviposition learning. Substantial differences in LTM formation are observed among closely related species of parasitic wasps, which provides excellent opportunities for comparative studies. Both ecological and genetic factors involved in variation in LTM formation have been studied in this project. A multidisciplinary approach is essential to understand the evolution of variation in LTM formation, because the interaction between genes and environment shapes learning and memory formation. LTM formation was studied in closely related species of the genus Nasonia. These small parasitic wasps (~2 mm in length) lay their eggs in various species of fly pupae and differences in the ecology of the four known species of this genus have been described. A high-throughput method for olfactory conditioning was developed in which the wasps associated an odour, either chocolate or vanilla, with the reward of a host. A T-maze olfactometer was designed for high-throughput testing of memory retention. Using these methods, variation in memory retention was observed between three Nasonia species. Both N. vitripennis and N. longicornis form a long-lasting memory after a single conditioning trial, which lasts at least 5 days. Nasonia giraulti, on the other hand, lost its memory after 1 to 2 days after a single conditioning trial. Further studies focused on the difference between N. vitripennis and N. giraulti, which was most pronounced. By inhibiting LTM with transcription and translation inhibitors, it was confirmed that N. vitripennis forms this type of memory after a single conditioning trial. LTM is visible 4 days after conditioning in N. vitripennis. Nasonia giraulti does not form LTM after a single conditioning trial. Long-lasting memory is only formed after two trials, with a 4-hour interval between them. This difference in LTM formation makes N. vitripennis and N. giraulti excellent model species to study both ecological and genetic factors involved in this difference. Ecological factors such as the value of the reward and the reliability of the learned association have been shown to affect memory formation in a number of animal species. A recent study on oviposition learning in two parasitic wasp species demonstrated that LTM formation depends on the host species, i.e. the reward offered during conditioning. LTM was formed when a host with a higher quality was offered, but not when a host of lower quality was offered. The effect of host quality on memory retention of N. vitripennis and N. giraulti was tested. Either a large host, Calliphora vomitoria, a medium-sized host, Lucilia sericata, or a small host, Musca domestica, was offered during conditioning. These hosts were observed to differ significantly in their quality, i.e. in the number of parasitoid offspring that emerged and the size of the offspring. There was, however, no effect of host species on memory retention in either Nasonia species. These results suggest that host quality is not important for LTM formation in N. vitripennis and N. giraulti. This observation shows that ecological factors that are important for memory formation in one species may not be important for another species. The genetic basis of memory formation is highly conserved among distant animal phyla. A large number of genes involved in LTM formation have been identified in genetic model organisms, including fruit flies, honeybees, the California sea hare, mice and rats, and the zebra finch.Genetic factors responsible for natural variation in LTM formation between species are currently unknown, however. Two approaches were used to study genetic factors responsible for the difference in LTM formation between N. vitripennis and N. giraulti. The first approach took advantage of the unique possibility to interbreed Nasonia species. Hybrid offspring of N. vitripennis and N. giraulti did not form LTM after a single conditioning trial, similar to N. giraulti. The dominant LTM phenotype of N. giraulti was then backcrossed into the genetic background of N. vitripennis for up to 5 generations. Using a genotyping microarray analysis and subsequent confirmation experiments, we detected two genomic regions (quantitative trait loci – QTLs) that both reduce long-lasting memory, but not completely remove this memory. These results indicate that multiple QTLs regulate the difference in LTM formation between the two Nasonia species. Concluding, our approach has provided insights in the genomic basis of a naturally occurring difference in LTM formation between two species. Excellent opportunities for fine-scale QTL mapping are available for the genus Nasonia. This will allow identification of decisive regulatory mechanisms involved in LTM formation that are located in the two genomic regions detected in this study. The second approach took advantage of next-generation sequencing techniques that allow transcriptome-wide studies of gene expression levels. RNA from heads of N. vitripennis and N. giraulti was collected before conditioning and immediately, 4 hours, or 24 hours after conditioning. This RNA was sequenced strand-specifically using HiSeq technology, which allows detection of sense and antisense transcripts. Various genes, from a number of different signalling pathways known to be involved in LTM formation, were uniquely differentially expressed after conditioning in N. vitripennis. These genes are likely involved in the ongoing process of LTM formation in this species. A number of other genes with a known role in LTM formation,including genes involved in dopamine synthesis and in the Ras-MAPK and PI3K signalling pathways, were uniquely differentially expressed in N. giraulti. These genes may have a role in a LTM inhibitory mechanism in this species. Antisense transcripts were detected for a number of known memory genes, which may indicate a role inregulation of transcription, alternative splicing, or translation. This study is the first to compare gene expression patterns after conditioning between two species that differ in LTM formation. The results provide promising candidate genes for future studies in which the regulation of these genes, the function of specific splice variants, and spatial expression patterns in the brain should be studied to understand how these genes are involved in the regulation of LTM formation. Learning and memory formation have an important role in animal and human behaviour.Novel and valuable insights on both ecological and genetic factors responsible for variation in LTM formation have been revealed by the research presented in this thesis. Integrating ecological factors and genetic factors is essential, as genes are the level on which ecological factors can drive the evolution of variation in learning and memory formation. The genus Nasonia has offered excellent opportunities for ecological research as well as unique opportunities for studies on genomic and genetic factors, which were addressed by comparing closely related species that differ in memory formation. This thesis provides the basis for the identification of genomic differences responsible for the difference in memory formation between Nasonia species, but it also characterized the consequences of these genomic differences on gene expression. The genetic basis of learning and memory formation are highly conserved among distant animal species and insights from this thesis are likely applicable to other animal species and humans, as well.Altogether, these small parasitic wasps allow us to understand and value differences in memory formation.</p

    Comparison of large aperture scintillometer and eddy covariance measurements: Can thermal infrared data be used to capture footprint-induced differences?

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    Eddy covariance (EC) and large aperture scintillometer (LAS) measurements were collected over an irrigated olive orchard near Marrakech, Morocco. The tall, sparse vegetation in the experimental site was relatively homogeneous, but during irrigation events spatial variability in soil humidity was large. This heterogeneity caused large differences between the source area characteristics of the EC system and the LAS, resulting in a large scatter when comparing sensible heat fluxes obtained from LAS and EC. Radiative surface temperatures were retrieved from thermal infrared satellite images from the Landsat Enhanced Thematical Mapper and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellites. Using these images in combination with an analytical footprint model, footprint-weighted radiative surface temperatures for the footprints of the LAS and the EC system were calculated. Comparisons between the difference in measured sensible heat fluxes and the difference in footprint-weighted radiative surface temperature showed that for differences between the footprint-weighted radiative surface temperatures larger than 0.5 K, correlations with the difference in measured sensible heat flux were good. It was found that radiative surface temperatures, obtained from thermal infrared satellite imagery, can provide a good indication of the spatial variability of soil humidity, and can be used to identify differences between LAS and EC measurements of sensible heat fluxes resulting from this variability

    Toward the optimal strategy for sustained weight loss in overweight cancer survivors: a systematic review of the literature

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    Purpose: To gain more insight into the optimal strategy to achieve weight loss and weight loss maintenance in overweight and obese cancer survivors after completion of initial treatment, this systematic review aimed to provide an overview of the literature on intervention effects on weight, to describe intervention components used in effective interventions, to identify and synthesize behaviour change techniques (BCTs) and to assess the frequency with which these BCTs were used in effective interventions. / Methods: Six databases were searched for original research articles describing weight changes in adult overweight cancer survivors after participation in a lifestyle intervention initiated after completion of initial treatment. Two researchers independently screened the retrieved papers and extracted BCTs using the BCT Taxonomy version 1. / Results: Thirty-two papers describing 27 interventions were included. Interventions that were evaluated with a robust study design (n = 8) generally showed <5% weight loss and did not evaluate effects at ≥12 months after intervention completion. Effective interventions promoted both diet and physical activity and used the BCTs ‘goal setting (behaviour)’, ‘action planning’, ‘social support (unspecified)’ and ‘instruction on how to perform the behaviour’. / Conclusions: The results of this first review on intervention components of effective interventions could be used to inform intervention development and showed a need for future publications to report long-term effects, a detailed intervention description and an extensive process evaluation. / Implications for cancer survivors: This study contributed to increasing knowledge on the optimal strategy to achieve weight loss, which is recommended for overweight cancer survivors to improve health outcomes

    Iris Yellow Spot Virus in the Netherlands: Occurence in Onion and Confirmation of Transmission by Thrips tabaci

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    Since its first detection in the Netherlands in 1992, Iris yellow spot virus (IYSV, genus Tospovirus) has been reported worldwide in Allium crops, in a few ornamentals and in a small number of weeds. After recent findings of IYSV in Alstroemeria and Eustoma in the Netherlands, a number of neighbouring onion fields were surveyed. In 2005 and 2006, only few infected plants were found with obvious symptoms of IYSV. In 2007, after sampling and testing small leaf samples with various types of damage, including small brown-yellow colored spots and spots with thrips feeding damage, a high percentage of plants were found with positive IYSV scores in ELISA. Infection by IYSV could be confirmed in most ELISA-positive samples by RT-PCR. Under laboratory conditions, evidence was obtained that Thrips tabaci acts as a vector for this virus. Acquisition of the IYSV from infected Datura stramonium plants resulted in virus uptake and replication in over 60% of the thrips exposed, as determined by Western blotting and immunolocalisation of the virus in the foregut, and in epithelial and midgut muscle cells using antibodies against both the viral N and NSs proteins. Successful transmission of IYSV to seedlings of Emilia sonchifolia was observed, however, only at low frequency under the laboratory conditions used

    Using the behavior change wheel to identify and understand key facilitators and barriers for lifestyle care for postmenopausal breast cancer survivors:A delphi-study

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    BackgroundOptimal approaches to promote sustained adherence to lifestyle and bodyweight recommendations in postmenopausal breast cancer (PMBC) survivors are lacking.PurposeThis Delphi-study aims to identify and understand expert-opinion on potential barriers and facilitators for promoting adherence to these lifestyle and bodyweight recommendations in (clinical) care for PMBC survivors, and to determine potential effective intervention strategies.MethodsThe expert panel consisted of oncology Health Care Professionals (HCPs) (N = 57), patient advocates (N = 5), and PMBC survivors (N = 38). They completed three questionnaires: Q1—idea generation; Q2—validation and prioritization; Q3—ranking. The Behavior Change Wheel was used as theoretical framework for analysis. Thematic analysis was applied to identify key overarching themes based on the top-ranked facilitators and barriers. Potential Behavior Change Techniques (BCTs) and intervention strategies were identified using the Behavior Change Technique Taxonomy version 1 and the Behavior Change Wheel.ResultsEleven core categories of key barriers/facilitators for the promotion of adherence to recommendations for lifestyle and bodyweight among PMBC survivors were identified. For each core category, relevant BCTs and practical potential intervention strategies were selected based on suggestions from the expert panel. These included: increasing knowledge about the link between lifestyle and cancer; enabling self-monitoring of lifestyle behaviors followed by evaluation; offering group lifestyle counseling for PMBC survivors, enhancing social support for favorable lifestyle behaviors; and stimulating multidisciplinary collaboration among HCPs.ConclusionsFindings provide valuable insight for the development of interventions changing behavior of PMBC survivors and HCPs toward increased healthy lifestyle (support) behavior
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