24 research outputs found

    Towards OPtimal TIming and Method for promoting sUstained adherence to lifestyle and body weight recommendations in postMenopausal breast cancer survivors (the OPTIMUM-study):protocol for a longitudinal mixed-method study

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    BACKGROUND: The majority of postmenopausal breast cancer (PMBC) survivors do not adhere to lifestyle recommendations and have excess body weight. In this group, this is associated with poorer health-related quality of life and an increased risk of type II diabetes mellitus, cardiovascular disease, second primary cancers, cancer recurrences, and mortality. Gaining and maintaining a healthy lifestyle and body composition is therefore important. It is unknown when and how sustained adherence to these recommendations can be promoted optimally in PMBC survivors. Therefore, the OPTIMUM study aims to identify the optimal timing and method for promoting sustained adherence to lifestyle and body weight recommendations in PMBC survivors. METHODS: The OPTIMUM-study has a mixed-methods design. To assess optimal timing, a longitudinal observational study will be conducted among approximately 1000 PMBC survivors. The primary outcomes are adherence to lifestyle and body weight recommendations, readiness for change, and need for support. Questionnaires will be administered at 4–6 months after cancer diagnosis (wave 1: during treatment and retrospectively before diagnosis), 1 year after diagnosis (wave 2: after completion of initial treatment), and 1.5 years after diagnosis (wave 3: during follow-up). Wave 2 and 3 include blood sampling, and either wearing an accelerometer for 7 days or completing a 3-day online food diary (randomly assigned at hospital level). To assess the optimal method, behavioural determinants of the primary outcomes will be matched with Behavior Change Techniques using the Behaviour Change Technique Taxonomy. Qualitative research methods will be used to explore perceptions, needs and preferences of PMBC survivors (semi-structured interviews, focus groups) and health care providers (Delphi study). Topics include perceptions on optimal timing to promote adherence; facilitators and motivators of, and barriers towards (sustained) adherence to recommendations; and acceptability of the selected methods. DISCUSSION: The OPTIMUM study aims to gain scientific knowledge on when and how to promote sustained adherence to lifestyle and body weight recommendations among PBMC survivors. This knowledge can be incorporated into guidelines for tailored promotion in clinical practice to improve health outcomes

    SPO11-Independent DNA Repair Foci and Their Role in Meiotic Silencing

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    In mammalian meiotic prophase, the initial steps in repair of SPO11-induced DNA double-strand breaks (DSBs) are required to obtain stable homologous chromosome pairing and synapsis. The X and Y chromosomes pair and synapse only in the short pseudo-autosomal regions. The rest of the chromatin of the sex chromosomes remain unsynapsed, contains persistent meiotic DSBs, and the whole so-called XY body undergoes meiotic sex chromosome inactivation (MSCI). A more general mechanism, named meiotic silencing of unsynapsed chromatin (MSUC), is activated when autosomes fail to synapse. In the absence of SPO11, many chromosomal regions remain unsynapsed, but MSUC takes place only on part of the unsynapsed chromatin. We asked if spontaneous DSBs occur in meiocytes that lack a functional SPO11 protein, and if these might be involved in targeting the MSUC response to part of the unsynapsed chromatin. We generated mice carrying a point mutation that disrupts the predicted catalytic site of SPO11 (Spo11YF/YF), and blocks its DSB-inducing activity. Interestingly, we observed foci of proteins involved in the processing of DNA damage, such as RAD51, DMC1, and RPA, both in Spo11YF/YFand Spo11 knockout meiocytes. These foci preferentially localized to the areas that undergo MSUC and form the so-called pseudo XY body. In SPO11-deficient oocytes, the number

    Motor learning and movement automatization in typically developing children: The role of instructions with an external or internal focus of attention

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    The aim of the current study was to examine the effects of an external focus of attention (i.e., on the movement outcome) versus an internal focus of attention (i.e., on the movement itself) on motor learning in typically developing children. We examined both immediate motor performance (i.e., practice effect, when focus instructions are given) as well as motor performance after one week (i.e., learning effect). In addition, we examined if an external and an internal focus of attention differently affected movement automatization, as measured using a dual-task paradigm. Finally, we explored whether the effect of attentional focus instructions on motor learning was influenced by children’s working memory capacity. Participants were 8–12 year old (N = 162) typically developing children. Participants practiced a new motor task (i.e., ‘Slingerball throwing task’). Results showed that an external focus of attention led to higher throwing accuracy during practice, but this beneficial effect did not extent to the retention test one week later. Furthermore, movement automatization did not differ after external or internal focus of attention instructions, and working memory capacity did not predict motor learning in children in either of the instruction conditions. This is the first study to show that the beneficial effects of an external focus of attention on discrete motor tasks found in previous studies with a child population seem to be short lived and decline after a one-week interval

    Dissolved inorganic carbon and alkalinity fluxes from coastal marine sediments: model estimates for different shelf environments and sensitivity to global change

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    We present a one-dimensional reactive transport model to estimate benthic fluxes of dissolved inorganic carbon (DIC) and alkalinity (<i>A</i><sub>T</sub>) from coastal marine sediments. The model incorporates the transport processes of sediment accumulation, molecular diffusion, bioturbation and bioirrigation, while the reactions included are the redox pathways of organic carbon oxidation, re-oxidation of reduced nitrogen, iron and sulfur compounds, pore water acid-base equilibria, and dissolution of particulate inorganic carbon (calcite, aragonite, and Mg-calcite). The coastal zone is divided into four environmental units with different particulate inorganic carbon (PIC) and particulate organic carbon (POC) fluxes: reefs, banks and bays, carbonate shelves and non-carbonate shelves. Model results are analyzed separately for each environment and then scaled up to the whole coastal ocean. The model-derived estimate for the present-day global coastal benthic DIC efflux is 126 Tmol yr<sup>−1</sup>, based on a global coastal reactive POC depositional flux of 117 Tmol yr<sup>−1</sup>. The POC decomposition leads to a carbonate dissolution from shallow marine sediments of 7 Tmol yr<sup>−1</sup> (on the order of 0.1 Pg C yr<sup>−1</sup>. Assuming complete re-oxidation of aqueous sulfide released from sediments, the effective net flux of alkalinity to the water column is 29 Teq. yr<sup>−1</sup>, primarily from PIC dissolution (46%) and ammonification (33%). Because our POC depositional flux falls in the high range of global values given in the literature, the reported DIC and alkalinity fluxes should be viewed as upper-bound estimates. Increasing coastal seawater DIC to what might be expected in year 2100 due to the uptake of anthropogenic CO<sub>2</sub> increases PIC dissolution by 2.3 Tmol yr<sup>−1</sup>and alkalinity efflux by 4.8 Teq. yr<sup>−1</sup>. Our reactive transport modeling approach not only yields global estimates of benthic DIC, alkalinity and nutrient fluxes under variable scenarios of ocean productivity and chemistry, but also provides insights into the underlying processes

    Self-performed Five Times Sit-To-Stand test at home as (pre-)screening tool for frailty in cancer survivors:Reliability and agreement assessment

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    Aims and objectives:  The self-performance of a Five-Times-Sit-To-Stand (FTSTS)-test, without the usual supervision by a medical professional, provides valuable opportunities for clinical practice and research. This study aimed: (1) to determine the validity of the self-performed FTSTS test in comparison to a supervised reference test and (2) to determine the reliability of a self-performed FTSTS test by cancer survivors. Background:  Early detection of frailty in cancer survivors may enable prehabilitation interventions before surgery or intensive treatment, improving cancer outcomes. Design:  A repeated measures reliability and agreement study, with one week in between measures, was performed. Methods:  Cancer survivors (n = 151) performed two FTSTS tests themselves. One additional reference FTSTS test was supervised by a physical therapist. The intraclass correlation coefficient (ICC), structural error of measurement (SEM) and minimally important clinical difference (MID) were calculated comparing a self-performed FTSTS test to the reference test, and comparing two self-performed FTSTS tests. The Guidelines for Reporting Reliability and Agreement Studies (GRASS) have been used. Results:  Mean age of cancer survivors was 65.6 years (SD = 9.3), 54.6% were female, median time since diagnosis was 2 years [IQR = 1], and tumour type varied (e.g., breast cancer (31.8%), prostate cancer (17.2%), gastrointestinal cancer (11.9%) and haematological cancer (11.9%)). Validity of the self-performed FTSTS test at home was acceptable in comparison with the reference test (ICC = .74; SEM = 3.2; MID = 3.6) as was the reliability of the self-performed FTSTS test (ICC = .70; SEM = 2.2; MID = 3.8). Conclusions:  The self-performed FTSTS test is a valid and reliable measure to assess lower body function and has potential to be used as objective (pre-)screening tool for frailty in cancer survivors. Relevance to clinical practice:  The self-performed FTSTS test at home may indicate the cancer survivors in need of prehabilitation in advance of surgery or intensive treatment. The feasibility, short amount of time needed and potential cost-effectiveness of the self-performed FTSTS test can make it a valuable contribution to personalised care and precision medicine

    Automatic determination of white matter hyperintensity properties in relation to the development of Alzheimer's disease

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    Alzheimer's disease (AD) is the most common form of dementia seen in the elderly. No curing medicine for AD exists at this moment. In the search for an effective medicine, research is directed towards the prediction of conversion of mild cognitive impairment (MCI) to AD. White matter hyperintensities (WMHs) have been shown to contain information regarding the development of AD, although non-conclusive results are found in literature. These studies often use qualitative measures to describe WMHs, which is time consuming and prone to variability. To investigate the relation between WMHs and the development of AD, algorithms to automatically determine quantitative properties in terms of volume and spatial distribution of WMHs are developed and compared between normal controls and MCI subjects. MCI subjects have a significantly higher total volume of WMHs than normal controls. This difference persists when lesions are classified according to their distance to the ventricular wall. Spatial distribution is also described by defining different brain regions based on a common coordinate system. This reveals that MCI subjects have a larger WMH volume in the upper part of the brain compared to normal controls. In four subjects, the change of WMH properties over time is studied in detail. Although such a small dataset cannot be used to give definitive conclusions, the data suggests that progression of WMHs in subjects with a low lesion load is caused by an increase in the number of lesions and by the progression of juxtacortical lesions. In subjects with a larger lesion load, progression is caused by expansion of pre-existing lesions

    Course of objectively measured physical activity and sleep in postmenopausal breast cancer survivors during the COVID-19 pandemic:A 1-year follow-up

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    BACKGROUND: As physical inactivity and poor sleep quality may impose additional risk for cancer recurrence and overall mortality in postmenopausal breast cancer (PMBC) survivors, it is important to gain insight into the effect of the COVID-19 pandemic on their physical activity (PA) and sleep level. OBJECTIVE: This study aimed to assess the course of their physical activity (PA) and sleep throughout governmental measures against COVID-19 during 12 months of the COVID-19 pandemic. METHODS: PMBC survivors (n = 96) wore an ActiGraph wGT3X-BT for seven consecutive days at 12 and 18 months after diagnosis and additional measurements were taken after onset of the second (partial) COVID-19 lockdown. Longitudinal data was categorized into four timepoints: before onset of COVID-19 (T1), during the initial lockdown (T2), in between initial and second lockdown (T3), and during the second lockdown (T4). General linear mixed effects models assessed differences in moderate-to-vigorous physical activity (MVPA) per day, total minutes of PA per day, average acceleration, intensity gradient, sleep efficiency, and sleep duration over time. RESULTS: Levels of MVPA per day before COVID-19 were low (Median = 20.9 min/day (IQR = 10.8;36.2)), and time spent physically active was most often in light intensity, which remained stable throughout the pandemic. Sleep duration (Median = 442.8 min/night (IQR = 418.3;478.0)) and efficiency (85.9% (IQR = 79.6;88.4)) was sufficient before COVID-19 and showed stability over time. CONCLUSIONS: Low levels of PA with mostly light intensity, and adequate sleep efficiency and duration were observed before COVID in PMBC survivors. This was not further affected by COVID-19 governmental measures.</p
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