31 research outputs found

    Diet-associated inflammation modulates inflammation and WNT signaling in the rectal mucosa, and the response to supplementation with dietary fiber

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    Inflammation drives colorectal cancer development, and colorectal cancer risk is influenced by dietary factors, including dietary fiber. Hyperactive WNT signaling occurs in colorectal cancer and may regulate inflammation. This study investigated (i) relationships between the inflammatory potential of diet, assessed using the Energy-adjusted Dietary Inflammatory Index (E-DII), and markers of WNT signaling, and (ii) whether DII status modulated the response to supplementation with two types of dietary fiber. Seventy-five healthy participants were supplemented with resistant starch and/or polydextrose (PD) or placebo for 50 days. Rectal biopsies were collected before and after intervention and used to assess WNT pathway gene expression and crypt cell proliferation. E-DII scores were calculated from food frequency questionnaire data. High-sensitivity C-reactive protein (hsCRP) and fecal calprotectin concentrations were quantified. hsCRP concentration was significantly greater in participants with higher E-DII scores [least square means (LSM) 4.7 vs. 2.4 mg/L, P = 0.03]. Baseline E-DII score correlated with FOSL1 (b = 0.503, P = 0.003) and WNT11 (b = 0.472, P = 0.006) expression, after adjusting for age, gender, body mass index, endoscopy procedure, and smoking status. WNT11 expression was more than 2-fold greater in individuals with higher E-DII scores (LSM 0.131 vs. 0.059, P = 0.002). Baseline E-DII modulated the effects of PD supplementation on FOSL1 expression (P = 0.04). More proinflammatory diets were associated with altered WNT signaling and appeared to modulate the effects of PD supplementation on expression of FOSL1. This is the first study to investigate relationships between the E-DII and molecular markers of WNT signaling in rectal tissue of healthy individuals

    Acquisition of Growth-Inhibitory Antibodies against Blood-Stage Plasmodium falciparum

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    Background: Antibodies that inhibit the growth of blood-stage Plasmodium falciparum may play an important role in acquired and vaccine-induced immunity in humans. However, the acquisition and activity of these antibodies is not well understood. Methods: We tested dialysed serum and purified immunoglobulins from Kenyan children and adults for inhibition of P. falciparum blood-stage growth in vitro using different parasite lines. Serum antibodies were measured by ELISA to bloodstage parasite antigens, extracted from P. falciparum schizonts, and to recombinant merozoite surface protein 1 (42 kDa Cterminal fragment, MSP1-42). Results: Antibodies to blood-stage antigens present in schizont protein extract and to recombinant MSP1-42 significantly increased with age and were highly correlated. In contrast, growth-inhibitory activity was not strongly associated with age and tended to decline marginally with increasing age and exposure, with young children demonstrating the highest inhibitory activity. Comparison of growth-inhibitory activity among samples collected from the same population at different time points suggested that malaria transmission intensity influenced the level of growth-inhibitory antibodies. Antibodies to recombinant MSP1-42 were not associated with growth inhibition and high immunoglobulin G levels were poorly predictive of inhibitory activity. The level of inhibitory activity against different isolates varied. Conclusions: Children can acquire growth-inhibitory antibodies at a young age, but once they are acquired they do not appear to be boosted by on-going exposure. Inhibitory antibodies may play a role in protection from early childhood malaria

    Protocol for the IDEAL-2 longitudinal study: Following the experiences of people with dementia and their primary carers to understand what contributes to living well with dementia and enhances active life

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    Background There is a major need for longitudinal research examining the experiences of people with dementia and their primary carers, as relatively little is known about how the factors associated with capability to ‘live well’ vary over time. The main aim of the IDEAL-2 study is to investigate how and why, over time, people with dementia and their primary carers might vary in their capability to live well with dementia, whilst exploring both their use of health and care services and their unmet needs. Methods IDEAL-2 will build on the Improving the experience of Dementia and Enhancing Active Life (IDEAL) cohort of 1547 people (who, at recruitment between July 2014 and July 2016, had mild-to-moderate dementia), and their 1283 primary carers in Great Britain. The existing cohort will be enriched with additional participants with mild-to-moderate dementia (and their primary carers where available and willing) from the following groups: people with rarer forms of dementia, and/or those who are ≥90 years or < 65 years of age at time of recruitment. We will assess the primary outcome, capability to live well with dementia, and the factors influencing it using questionnaires at yearly intervals for 3 years. Additionally, we will seek to link the cohort data with administrative data to obtain information about health service use. Some participants will be invited for in-depth face-to-face interviews. The cohort study will be supplemented by linked research focusing on: the co-production of new measures of living well; including the perspectives of people with advanced dementia living in residential care settings; including people with dementia from black, Asian, and minority ethnic groups; and understanding the experience of people living with undiagnosed dementia. Discussion IDEAL-2 will provide evidence about the key indicators of, and factors associated with, living well over the course of dementia and how these differ for particular subgroups. It will tell us which combinations of services and support are most beneficial and cost-effective. Moreover, the IDEAL-2 study will gather evidence from under-researched groups of people with dementia, who are likely to have their own distinct perceptions of living well.Alzheimer’s Society & The University of Exete

    Variation in use of erythrocyte invasion pathways by Plasmodium falciparum mediates evasion of human inhibitory antibodies

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    Antibodies that inhibit Plasmodium falciparum invasion of erythrocytes are believed to be an important component of immunity against malaria. During blood-stage infection, P. falciparum can use different pathways for erythrocyte invasion by varying the expression and/or utilization of members of 2 invasion ligand families: the erythrocyte-binding antigens (EBAs) and reticulocyte-binding homologs (PfRhs). Invasion pathways can be broadly classified into 2 groups based on the use of sialic acid (SA) on the erythrocyte surface by parasite ligands. We found that inhibitory antibodies are acquired by malaria-exposed Kenyan children and adults against ligands of SA-dependent and SA-independent invasion pathways, and the ability of antibodies to inhibit erythrocyte invasion depended on the pathway used by P. falciparum isolates. Differential inhibition of P. falciparum lines that varied in their use of specific EBA and PfRh proteins pointed to these ligand families as major targets of inhibitory antibodies. Antibodies against recombinant EBA and PfRh proteins were acquired in an age-associated manner, and inhibitory antibodies against EBA175 appeared prominent among some individuals. These findings suggest that variation in invasion phenotype might have evolved as a mechanism that facilitates immune evasion by P. falciparum and that a broad inhibitory response against multiple ligands may be required for effective immunity

    Randomised controlled trial of an online mental health and suicide gatekeeper resource for parents and caregivers: study protocol

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    Introduction Rates of help-seeking for mental disorders and suicide are low among children and adolescents. Parents are viewed as gatekeepers for their care, yet they may lack the knowledge and skills to identify needs or facilitate service access. The primary aim is to test the effect of a new gatekeeper resource for parents and caregivers on their self-efficacy to recognise, respond and access support for mental health problems and suicide risk in their child.Methods and analysis A two-arm randomised controlled trial will compare an online mental health and suicide gatekeeper resource for parents and caregivers to a waitlist control. Australian parents of children aged 5–17 years recruited through social media and community advertising will participate in an online trial. Participants randomised to the intervention condition will be emailed the resource to work through at their own pace. The resource consists of three sections providing parents and caregivers with confidence, knowledge and skills to recognise and respond to mental health problems and suicide risk in their child, as well as support them in accessing professional help. The primary outcome measure is self-efficacy to recognise, respond and provide support for mental health problems and suicide risk, while secondary outcomes include perceived knowledge, stigma, literacy, help-seeking attitudes, intentions and barriers. Data will be collected at preintervention, postintervention (4 weeks after accessing the resource) and 12-week follow-up. Primary analyses will compare changes in self-efficacy in the intervention condition relative to the waitlist control using mixed-model repeated measures analyses.Ethics and dissemination The ethical aspects of the study were approved by the Australian National University Human Research Ethics Committee (Protocol 2023/195). If effective, the resource will fill an important gap in resources for parents, with the potential for dissemination through school groups, community organisations and clinical settings.Trial registration number Australian New Zealand Clinical Trials Registry, ACTRN12623000933651

    Prevalence of antibodies to AMA1 or specific epitopes by age group in the Chonyi cohort.

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    <p>Antibodies to recombinant AMA1 protein were tested by standard ELISA. Antibodies to specific AMA1 epitopes were measured by assessing the ability of human serum antibodies to inhibit the binding of monoclonal antibodies 1F9 and 2C5 in competition ELISA. (<b>A</b>) IgG to recombinant AMA1 (P&lt;0.001), (<b>B</b>) inhibition of binding of mAb 1F9 epitope (P&lt;0.001), (<b>C</b>) inhibition of binding of mAb 2C5 (P = 0.028). P values were calculated using the Chi square test for trend excluding age 0 (&lt;1) years. Data represent the proportion of individuals with detectable IgG binding or inhibitory activity and error bars indicate 95% CI.</p

    Association between antibody responses and risk of clinical malaria in the Chonyi cohort.

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    <p>Notes.</p>1<p>Children were classified as high and low responders for antibodies based on being above or below the median level for the cohort.</p>2<p>Multivariable Cox proportional hazards adjusted for age.</p>3<p>Hazard ratios show the risk of <i>P. falciparum</i> malaria over a 6 month follow-up period comparing children who were high or low antibody responders to each antigen or epitope.</p>4<p>Parasitemia detected by light microscopy.</p

    Levels of inhibition of 1F9-binding by human antibodies according to age group and infection status in the Ngerenya cohort.

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    <p>Values show the level of inhibition of 1F9 mAb binding to AMA1 by human serum antibodies, stratified by infection status at the time of sample collection and grouped according to age. Boxes indicate median and interquartile range, and whiskers represent 95% CI. Positive 1F9 inhibition was defined as inhibition of 1F9 binding&gt;(mean +2 standard deviations of negative controls = 6.19%). Differences in the level of anti-1F9 activity among age groups was significant amongst aparasitemic individuals (P = 0.020, Kruskal Wallis test), but not amongst parasitemic individuals. The median level of anti-1F9 activity was lower amongst aparasitemic compared to parasitemic individuals (median inhibition [IQR] −0.1% [−2.8–1.7] vs 4.3% [−1.0–13.2], P = 0.002, Mann Whitney U test).</p

    Combined antibody responses to AMA1 and the risk of clinical malaria in the Chonyi cohort.

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    <p>Notes.</p>1<p>Children were classified as high and low responders for antibodies based on being above or below the median level for the cohort. Analysis compared children who were high responders to both antigens versus those who were low responders to both.</p>2<p>Multivariable Cox proportional hazards adjusted for age.</p>3<p>Hazard ratios show the risk of <i>P. falciparum</i> malaria over a 6 month follow-up period.</p
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