373 research outputs found

    Interpopulation hybridization results in widespread viability selection across the genome in Tigriopus californicus

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    <p>Abstract</p> <p>Background</p> <p>Genetic interactions within hybrids influence their overall fitness. Understanding the details of these interactions can improve our understanding of speciation. One experimental approach is to investigate deviations from Mendelian expectations (segregation distortion) in the inheritance of mapped genetic markers. In this study, we used the copepod <it>Tigriopus californicus</it>, a species which exhibits high genetic divergence between populations and a general pattern of reduced fitness in F2 interpopulation hybrids. Previous studies have implicated both nuclear-cytoplasmic and nuclear-nuclear interactions in causing this fitness reduction. We identified and mapped population-diagnostic single nucleotide polymorphisms (SNPs) and used these to examine segregation distortion across the genome within F2 hybrids.</p> <p>Results</p> <p>We generated a linkage map which included 45 newly elucidated SNPs and 8 population-diagnostic microsatellites used in previous studies. The map, the first available for the Copepoda, was estimated to cover 75% of the genome and included markers on all 12 <it>T. californicus </it>chromosomes. We observed little segregation distortion in newly hatched F2 hybrid larvae (fewer than 10% of markers at p < 0.05), but strikingly higher distortion in F2 hybrid adult males (45% of markers at p < 0.05). Hence, segregation distortion was primarily caused by selection against particular genetic combinations which acted between hatching and maturity. Distorted markers were not distributed randomly across the genome but clustered on particular chromosomes. In contrast to other studies in this species we found little evidence for cytonuclear coadaptation. Instead, different linkage groups exhibited markedly different patterns of distortion, which appear to have been influenced by nuclear-nuclear epistatic interactions and may also reflect genetic load carried within the parental lines.</p> <p>Conclusion</p> <p>Adult male F2 hybrids between two populations of <it>T. californius </it>exhibit dramatic segregation distortion across the genome. Distorted loci are clustered within specific linkage groups, and the direction of distortion differs between chromosomes. This segregation distortion is due to selection acting between hatching and adulthood.</p

    Mobile translators for non-English-speaking women accessing maternity services.

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    noIt is becoming increasingly common for midwives to care for women who do not speak English, and UK interpreting services are often inadequate and underused. Persistent language barriers have been found to contribute to maternal and perinatal mortality thus it is essential that these barriers are overcome to provide safe maternity care. This article reports on a two-stage study undertaken to address this. The study aimed to: • Identify difficulties midwives experience when communicating with non-English-speaking women. Through undertaking a group interview with 11 senior students, four themes emerged: accessing interpreters, working with interpreters, cultural barriers and strategies to address persistent language barriers • Explore the feasibility of using mobile devices with a translation application to communicate in clinical practice. Google Translate was tested in a simulated clinical environment with multi-lingual service users. Google Translate was not adequately developed to be safely used in maternity services. However, a maternity-specific mobile application could be built to help midwives and women communicate in the presence of a persistent language barrier

    Predictive genetic testing for Huntington's disease: Exploring participant experiences of uncertainty and ambivalence between clinic appointments

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    Ambivalence and uncertainty are key themes throughout the psychology of healthcare literature. This is especially so for individuals at risk of Huntington's disease (HD) deliberating the decision to undergo genetic testing because there is currently no treatment that modifies disease progression. A better understanding of the experience of making a decision about genetic prediction will help practitioners support and guide individuals through this process. Our aim was to capture participants' experiences of uncertainty and ambivalence in between their genetic counseling appointments. We explored these issues through the experiences of nine participants who were referred for predictive HD testing at four regional genetics services in England and Wales. Data consisted of recordings of clinic consultations, diaries, and an in‐depth interview conducted at the end of the testing process. Data were analyzed thematically. Four themes were identified representing four possible futures, each future dependent on the decision to undergo testing and the result of that test. Our results showed that participants, as well as attending more to a future that represents their current situation of not having undergone predictive testing, also attended more to a distant future where a positive predictive result is received and symptoms have started. Participants attended less to the two futures that were more immediate once testing was undertaken (a future where a positive result is received and symptoms have not started and a future where a negative result is received). The use of diaries gave us a unique insight into these participants' experiences of ambivalence and uncertainty, psychological distress, and the emotional burden experienced. These findings help inform discussions within the clinic appointment as well as encourage researchers to consider diary use as a method of exploring what happens for individuals outside of clinical encounters

    Inclusion at Scale: Deploying a Community-Driven Moderation Intervention on Twitch

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    Harassment, especially of marginalized individuals, on networked gaming and social media platforms has been identified as a significant issue, yet few HCI practitioners have attempted to create interventions tackling toxicity online. Aligning ourselves with the growing cohort of design activists, we present a case study of the GLHF pledge, an interactive public awareness campaign promoting positivity in video game live streaming. We discuss the design and deployment of a community-driven moderation intervention for GLHF, intended to empower the inclusive communities emerging on Twitch. After offering a preliminary report on the effects we have observed based on the more than 370,000 gamers who have participated to date, the paper concludes with a reflection on the challenges and opportunities of using design activism to positively intervene in large-scale media platforms

    Epigenetic change induced by in utero dietary challenge provokes phenotypic variability across multiple generations of mice

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    Transmission of epigenetic information between generations occurs in nematodes, flies and plants, mediated by specialised small RNA pathways, histone H3K9me3, H3K27me3, H4K16ac and DNA methylation 1-3 . In higher vertebrates, epidemiological and experimental evidence supports similar trans-generational effects 4,5 although the mechanisms that underpin these are incompletely understood 6-9 . We generated a luciferase reporter knock-in mouse for the imprinted Dlk1 locus, to visualise and track epigenetic fidelity across generations. We showed that exposure to high-fat diet (HFD) in pregnancy provokes sustained re-expression of the normally silent maternal Dlk1 allele in offspring, coincident with increased DNA methylation at the Dlk1 sDMR . Interestingly, maternal Dlk1 mis-expression was also evident in the next generation (F2), exclusively in animals derived from F1-exposed females. Oocytes from these females showed altered microRNA and gene expression, without any major changes in underlying DNA methylation, and correctly imprinted Dlk1 expression resumed in subsequent generations (F3 onwards). Our results reveal how canonical and non-canonical imprinting mechanisms enable the foetal epigenome to adapt to in utero challenge to modulate the properties of two successive generations of offspring

    Percutaneous coronary revascularization in patients with formerly "refractory angina pectoris in end-stage coronary artery disease" – Not "end-stage" after all

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    <p>Abstract</p> <p>Background</p> <p>Patients with refractory angina pectoris in end-stage coronary artery disease represent a severe condition with a higher reduction of life-expectancy and quality of life as compared to patients with stable coronary artery disease. It was the purpose of this study to invasively re-evaluate highly symptomatic patients with formerly diagnosed refractory angina pectoris in end-stage coronary artery disease for feasible options of myocardial revascularization.</p> <p>Methods</p> <p>Thirty-four Patients formerly characterized as having end stage coronary artery disease with refractory angina pectoris were retrospectively followed for coronary interventions.</p> <p>Results</p> <p>Of those 34 patients 21 (61.8%) were eventually revascularized with percutaneous interventional revascularization (PCI). Due to complex coronary morphology (angulation, chronic total occlusion) PCI demanded an above-average amount of time (66 ± 42 minutes, range 25–206 minutes) and materials (contrast media 247 ± 209 ml, range 50–750 ml; PCI guiding wires 2.0 ± 1.4, range 1–6 wires). Of PCI patients 7 (33.3%) showed a new lesion as a sign of progression of atherosclerosis. Clinical success rate with a reduction to angina class II or lower was 71.4% at 30 days. Surgery was performed in a total of8 (23.5%) patients with a clinical success rate of 62.5%. Based on an intention-to-treat 2 patients of originally 8 (25%) demonstrated clinical success. Mortality during follow-up (1–18 months) was 4.8% in patients who underwent PCI, 25% in patients treated surgically and 25% in those only treated medically.</p> <p>Conclusion</p> <p>The majority of patients with end-stage coronary artery disease can be treated effectively with conventional invasive treatment modalities. Therefore even though it is challenging and demanding PCI should be considered as a first choice before experimental interventions are considered.</p
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