793 research outputs found

    Nutrigenetics—Personalized Nutrition in the Genetic Age

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    Diet is an important modifiable determinant of disease, and it is becoming clear that diet and genetic risk factors are interactive in determining risk for diseases such as cardiovascular disease, diabetes and cancers. Advances in technology have improved our understanding of gene-nutrient interactions, and lead to the development of nutrigenetics, personalized nutrition based on genetics. While evidence is strong for some associations, others remain unclear. As such, the implementation of nutrigenetics remains controversial. While some argue it is not ready for clinical use, it has also been argued that nutrigenetics is unfairly held to a higher standard than traditional nutrition research. Despite the future promise of nutrigenetic testing for improving health outcomes, several barriers in science, technology, acceptance and ethics exist to its implementation. Gene-nutrient associations have been identified in a number of lifestyle-associated diseases, and better understanding of these relationships may lead to improved health outcomes. However, the success of nutrigenetics is not only dependent on the strength of the science, but in consumer acceptance and uptake. This narrative review provides an overview of the current landscape for nutrigenetics in relation to key disease states, and addresses the potential barriers to implementation

    The Role of Practice Research Networks (PRN) in the Development and Implementation of Evidence: The Northern Improving Access to Psychological Therapies PRN Case Study

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    Practice research networks (PRNs) can support the implementation of evidence based practice in routine services and generate practice based evidence. This paper describes the structure, processes and learning from a new PRN in the Improving Access to Psychological Therapies programme in England, in relation to an implementation framework and using one study as a case example. Challenges related to: ethics and governance processes; communications with multiple stakeholders; competing time pressures and linking outcome data. Enablers included: early tangible outputs and impact; a collaborative approach; engaging with local research leads; clarity of processes; effective dissemination; and committed leadership

    Folic acid fortification and public health: Report on threshold doses above which unmetabolised folic acid appear in serum

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    BACKGROUND: All flour in the USA is fortified with folic acid at a level of 140 μg/100 g which is estimated to supply an extra 100 μg daily to the average diet. Some researchers have advocated that this be increased to double and even four times this amount. Based on previous research these higher levels are likely to lead to the appearance of unmetabolised vitamin in the circulation, which may have safety implications for sub-groups of the population. The UK and the Republic of Ireland will likely introduce mandatory fortification also in the next year or so. The aim of this study was to capture the short-term effect of folic acid fortification on unmetabolised folic acid in serum after chronic consumption of folic acid. METHODS: After pre-saturation with 400 μg folic acid supplements daily for 14-weeks, healthy folate replete adults (n = 20) consumed folic acid fortified bread, at three different levels (400 μg, 200 μg, 100 μg) over a period of one week each. The dose was administered in two-equal sized slices consumed at 09.00 hrs and 13.00 hrs. Serum samples for total folate and folic acid were collected at baseline, after 14-weeks of supplementation, and pre and post (at 1, 2, 3 and 4 hours) each dose tested. RESULTS: Unmetabolised folic acid was detected after the 14-week supplementation period. Folic acid was not detected in either the 200 μg or 100 μg (current US regime) doses tested but was present at the highest level (400 μg) tested. CONCLUSION: Our findings suggest that persons exposed to the current US fortification programme supplying an average of 100 μg per day or less are unlikely to have unmetabolised folic acid in serum. It also seems that daily consumption of the higher level of 200 μg or less is unlikely to be problematic. Increasing the level however to 400 μg on the other hand is likely to lead to unmetabolised folic acid appearance

    New Strategies for Research in Clinical Practice: A focus on self–harm.

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    This article suggests new ways of approaching clinical-based research in an era of evidence-based practice. Using the example of self-harm, we identify three distinct problems with current dominant approaches to research in this area. These include insufficient clarity about target issues, an overreliance on predetermined outcomes which prioritise behavioural measures (such as self-harm cessation) and an undue focus on treatment techniques. We argue that clinical research requires flexible, user-centred and practice-based methods, informed by a focus on principles instead of techniques. Therefore, we outline key practice-based principles that we argue need to be embedded within clinical research strategies. We then demonstrate how traditional behavioural approaches to research can be enriched with more qualitative cognitive and emotionally based data. We conclude that such strategies provide thickened, meaningful and context-specific research which is more relevant for service commissioners, clinicians and service users

    Human genetic selection on the MTHFR 677C>T polymorphism

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    <p>Abstract</p> <p>Background</p> <p>The prevalence of genotypes of the 677C>T polymorphism for the MTHFR gene varies among humans. In previous studies, we found changes in the genotypic frequencies of this polymorphism in populations of different ages, suggesting that this could be caused by an increase in the intake of folate and multivitamins by women during the periconceptional period. The aim was to analyze changes in the allelic frequencies of this polymorphism in a Spanish population, including samples from spontaneous abortions (SA).</p> <p>Methods</p> <p>A total of 1305 subjects born in the 20th century were genotyped for the 677C>T polymorphism using allele specific real-time PCR with Taqman<sup>® </sup>probes. A section of our population (n = 276) born in 1980–1989 was compared with fetal samples (n = 344) from SA of unknown etiology from the same period.</p> <p>Results</p> <p>An increase in the frequency of the T allele (0.38 vs 0.47; p < 0.001) and of the TT genotype (0.14 vs 0.24; p < 0.001) in subjects born in the last quarter of the century was observed. In the 1980–1989 period, the results show that the frequency of the wild type genotype (CC) is about tenfold lower in the SA samples than in the controls (0.03 vs 0.33; p < 0.001) and that the frequency of the TT genotype increases in the controls (0.19 to 0.27) and in the SA samples (0.20 to 0.33 (p < 0.01)); r = 0.98.</p> <p>Conclusion</p> <p>Selection in favor of the T allele has been detected. This selection could be due to the increased fetal viability in early stages of embryonic development, as is deduced by the increase of mutants in both living and SA populations.</p

    Pemetrexed pharmacokinetics and pharmacodynamics in a phase I/II study of doublet chemotherapy with vinorelbine: implications for further optimisation of pemetrexed schedules

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    The purpose of this study was to investigate the utility of plasma pharmacokinetic and pharmacodynamic measures including plasma deoxynucleosides, homocysteine and methylmalonic acid concentrations in understanding the time course and extent of the inhibition of thymidylate synthase (TS) by pemetrexed in the context of a phase I/II combination study with vinorelbine. Eighteen patients received supplementation with folic acid and Vitamin B12 1 week before beginning treatment with pemetrexed and vinorelbine administered in a dose-escalating manner on a 21-day cycle. Heparinised blood samples were collected from consenting patients in the first cycle for pharmacokinetic analyses and in the first two cycles for determination of plasma thymidine, deoxyuridine, homocysteine and methylmalonic acid concentrations. These values were correlated with response and toxicity. Plasma deoxyuridine was used as a measure of TS inhibition, and concentrations of deoxyuridine were significantly elevated relative to baseline on days 1 (P<0.01), 2 (P<0.001) and 3 (P<0.05) after treatment at all pemetrexed dose levels (400–700 mg m−2). The magnitude of deoxyuridine elevation correlated with pemetrexed area under the plasma concentration–time curve (AUC) (r2=0.23, P<0.05). However, deoxyuridine concentrations returned to baseline between 8 and 15 days after treatment with pemetrexed, suggesting that inhibition of TS was not durable. Pemetrexed AUC correlated with the percentage decline (relative to baseline) in both platelets (r2=0.58, P<0.001) and leucocytes (r2=0.26, P<0.05) at day 8. Baseline homocysteine was also significantly correlated with these measures of haematological toxicity (r2=0.37, P<0.01 and r2=0.39, P<0.01, respectively). In addition, there was a significant reduction of plasma homocysteine on days 8 (P<0.005) and 15 (P<0.05) in cycle 1 compared to baseline values. The results suggest that the TS inhibitory effects of pemetrexed are short-lived and make the case for a more frequent schedule of administration such as every 2 weeks. The lack of protracted TS inhibition may be due to concomitant vitamin administration, and this may be the mechanism by which vitamins prevent life-threatening toxicity from pemetrexed. Baseline homocysteine concentration remains a predictive marker for haematological toxicity even following folate supplementation

    Feasibility of familial PSA screening: psychosocial issues and screening adherence

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    This study examined factors that predict psychological morbidity and screening adherence in first-degree relatives (FDRs) taking part in a familial PSA screening study. Prostate cancer patients (index cases – ICs) who gave consent for their FDRs to be contacted for a familial PSA screening study to contact their FDRs were also asked permission to invite these FDRs into a linked psychosocial study. Participants were assessed on measures of psychological morbidity (including the General Health Questionnaire; Cancer Worry Scale; Health Anxiety Questionnaire; Impact of Events Scale); and perceived benefits and barriers, knowledge; perceived risk/susceptibility; family history; and socio-demographics. Of 255 ICs, 155 (61%) consented to their FDRs being contacted. Of 207 FDRs approached, 128 (62%) consented and completed questionnaires. Multivariate logistic regression revealed that health anxiety, perceived risk and subjective stress predicted higher cancer worry (P=0.05). Measures of psychological morbidity did not predict screening adherence. Only past screening behaviour reliably predicted adherence to familial screening (P=0.05). First-degree relatives entering the linked familial PSA screening programme do not, in general, have high levels of psychological morbidity. However, a small number of men exhibited psychological distress

    Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

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    Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate
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