74 research outputs found

    Parasitophorous vacuole poration precedes its rupture and rapid host erythrocyte cytoskeleton collapse in Plasmodium falciparum egress.

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    In the asexual blood stages of malarial infection, merozoites invade erythrocytes and replicate within a parasitophorous vacuole to form daughter cells that eventually exit (egress) by sequential rupture of the vacuole and erythrocyte membranes. The current model is that PKG, a malarial cGMP-dependent protein kinase, triggers egress, activating malarial proteases and other effectors. Using selective inhibitors of either PKG or cysteine proteases to separately inhibit the sequential steps in membrane perforation, combined with video microscopy, electron tomography, electron energy loss spectroscopy, and soft X-ray tomography of mature intracellular Plasmodium falciparum parasites, we resolve intermediate steps in egress. We show that the parasitophorous vacuole membrane (PVM) is permeabilized 10-30 min before its PKG-triggered breakdown into multilayered vesicles. Just before PVM breakdown, the host red cell undergoes an abrupt, dramatic shape change due to the sudden breakdown of the erythrocyte cytoskeleton, before permeabilization and eventual rupture of the erythrocyte membrane to release the parasites. In contrast to the previous view of PKG-triggered initiation of egress and a gradual dismantling of the host erythrocyte cytoskeleton over the course of schizont development, our findings identify an initial step in egress and show that host cell cytoskeleton breakdown is restricted to a narrow time window within the final stages of egress

    Aetiology of childhood pneumonia in low- and middle-income countries in the era of vaccination: a systematic review.

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    BACKGROUND: This systematic review aimed to describe common aetiologies of severe and non-severe community acquired pneumonia among children aged 1 month to 9 years in low- and middle-income countries. METHODS: We searched the MEDLINE, EMBASE, and PubMed online databases for studies published from January 2010 to August 30, 2020. We included studies on acute community-acquired pneumonia or acute lower respiratory tract infection with ≥1 year of continuous data collection; clear consistent case definition for pneumonia; >1 specimen type (except empyema studies where only pleural fluid was required); testing for >1 pathogen including both viruses and bacteria. Two researchers reviewed the studies independently. Results were presented as a narrative summary. Quality of evidence was assessed with the Quality Assessment Tool for Quantitative Studies. The study was registered on PROSPERO [CRD42020206830]. RESULTS: We screened 5184 records; 1305 duplicates were removed. The remaining 3879 titles and abstracts were screened. Of these, 557 articles were identified for full-text review, and 55 met the inclusion criteria - 10 case-control studies, three post-mortem studies, 11 surveillance studies, eight cohort studies, five cross-sectional studies, 12 studies with another design and six studies that included patients with pleural effusions or empyema. Studies which described disease by severity showed higher bacterial detection (Streptococcus pneumoniae, Staphylococcus aureus) in severe vs non-severe cases. The most common virus causing severe disease was respiratory syncytial virus (RSV). Pathogens varied by age, with RSV and adenovirus more common in younger children. Influenza and atypical bacteria were more common in children 5-14 years than younger children. Malnourished and HIV-infected children had higher rates of pneumonia due to bacteria or tuberculosis. CONCLUSIONS: Several viral and bacterial pathogens were identified as important targets for prevention and treatment. Bacterial pathogens remain an important cause of moderate to severe disease, particularly in children with comorbidities despite widespread PCV and Hib vaccination

    Burn injury leads to increased long-term susceptibility to respiratory infection in both mouse models and population studies

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    Background: Burn injury initiates an acute inflammatory response that subsequently drives wound repair. However, acute disruption to the immune response is also common, leading to susceptibility to sepsis and increased morbidity and mortality. Despite increased understanding of the impact of burn injury on the immune system in the acute phase, little is known about longterm consequences of burn injury on immune function. This study was established to determine whether burn injury has long-term clinical impacts on patients' immune responses. Methods: Using a population-based retrospective longitudinal study and linked hospital morbidity and death data from Western Australia, comparative rates of hospitalisation for respiratory infections in burn patients and a non-injured comparator cohort were assessed. In addition, a mouse model of non-severe burn injury was also used in which viral respiratory infection was induced at 4 weeks post-injury using a mouse modified version of the Influenza A virus (H3NN; A/mem/71-a). Results and conclusions: The burn injured cohort contained 14893 adult patients from 1980-2012 after removal of those patients with evidence of smoke inhalation or injury to the respiratory tract. During the study follow-up study a total of 2,884 and 2,625 respiratory infection hospital admissions for the burn and uninjured cohorts, respectively, were identified. After adjusting for covariates, the burn cohort experienced significantly elevated admission rates for influenza and viral pneumonia (IRR, 95%CI: 1.73, 1.27-2.36), bacterial pneumonia (IRR, 95%CI: 2.05, 1.85-2.27) and for other types of upper and lower respiratory infections (IRR, 95% CI: 2.38, 2.09-2.71). In the mouse study an increased viral titre was observed after burn injury, accompanied by a reduced CD8 response and increased NK and NKT cells in the draining lymph nodes. This data suggests burn patients are at long-term increased risk of infection due to sustained modulation of the immune response

    Development of gaze aversion: qualitiative changes over the early school years

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    Looking away from an interlocutors’ face during demanding cognitive activity can help adults and children answer challenging mental arithmetic and verbal-reasoning questions (Glenberg, Schroeder, & Robertson, 1998; Phelps, Doherty-Sneddon & Warnock, in press). Whilst such ‘gaze aversion’ (GA) is used far less by 5-year old school children, its use increases dramatically during the first years of primary education, reaching adult levels by 8-years of age (Doherty-Sneddon, Bruce, Bonner, Longbotham, & Doyle, 2002). The current study investigates whether developmental changes also occur in a qualitative aspect of GA - the direction of movement involved in GA shifts. Video data from 18 5-year-olds and 19 8-year-olds answering verbal and arithmetic questions were analysed for direction of GA. We found very different profiles of direction of GA across the two ages: whilst the 5-year-olds used predominantly rapid multi-directional ‘flicking’ movements and some sustained left lateral movements, the 8-year-olds used predominantly sustained rightward movements. It is concluded that, as well as quantitative increases in the use of GA across these age groups, there are concomitant qualitative changes in the nature of GA shifts. A model of human attention in face-to-face interaction is discussed as are implications for the assessment of children’s learning and development

    INCRESE: Development of an Inventory to Characterize Recorded Mental Health Recovery Narratives

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    Objective: Mental health recovery narratives are increasingly used in clinical practice, public health campaigns, and a directly-accessed online resources. No instrument exists to describe characteristics of individual recovery narratives. The aims were to develop and evaluate an inventory to characterize recorded recovery narratives. Research Design and Methods: A preliminary version of the Inventory of Characteristics of Recovery Stories (INCRESE) was generated from an existing theory-base. Feasibility and acceptability were evaluated by two coders each rating 3- purposively-selected narratives. A refined version was produced and a formal evaluation conducted. Reliability was assessed by four coders each rating 95 purposively-selected narratives. Inter-coder reliability was assessed using Fleiss’s kappa coefficients; test-retest reliability was assessed using intra-class correlation coefficients (ICCs). Results:  Multiple refinements to description, coding categories, and language were made. Data completeness was high, and no floor or ceiling effects were found. Inter-coder reliability ranged from moderate (k=0.58) to perfect (k=1.00) agreement. Test-retest reliability ranged from moderate (ICC=0.57) to complete (ICC=1.00) agreement. The final INCRESE comprises 77 items spanning five sections: Narrative Eligibility; Narrative Mode; Narrator Characteristics; Narrative Characteristics; Narrative Content.  Conclusion: INCRESE is the first evaluated tool to characterize mental health recovery narratives. It addresses current concerns around normative recovery narratives being used to promote compulsory wellness, e.g. by identifying narratives that reject diagnosis as an explanatory model and those with non-upward trajectories. INCRESE can be used to establish the diversity of a narrative collection and will be used in the NEON trials (ISRCTN11152837, ISRCTN63197153, ISRCTN76355273) to allow a recommender system to match narratives to participants

    The mechanisms and processes of connection: developing a causal chain model capturing impacts of receiving recorded mental health recovery narratives.

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    BACKGROUND: Mental health recovery narratives are a core component of recovery-oriented interventions such as peer support and anti-stigma campaigns. A substantial number of recorded recovery narratives are now publicly available online in different modalities and in published books. Whilst the benefits of telling one's story have been investigated, much less is known about how recorded narratives of differing modalities impact on recipients. A previous qualitative study identified connection to the narrator and/or to events in the narrative to be a core mechanism of change. The factors that influence how individuals connect with a recorded narrative are unknown. The aim of the current study was to characterise the immediate effects of receiving recovery narratives presented in a range of modalities (text, video and audio), by establishing the mechanisms of connection and the processes by which connection leads to outcomes. METHOD: A study involving 40 mental health service users in England was conducted. Participants were presented with up to 10 randomly-selected recovery narratives and were interviewed on the immediate impact of each narrative. Thematic analysis was used to identify the mechanisms of connection and how connection leads to outcome. RESULTS: Receiving a recovery narrative led participants to reflect upon their own experiences or those of others, which then led to connection through three mechanisms: comparing oneself with the narrative and narrator; learning about other's experiences; and experiencing empathy. These mechanisms led to outcomes through three processes: the identification of change (through attending to narrative structure); the interpretation of change (through attending to narrative content); and the internalisation of interpretations. CONCLUSIONS: This is the first study to identify mechanisms and processes of connection with recorded recovery narratives. The empirically-based causal chain model developed in this study describes the immediate effects on recipients. This model can inform selection of narratives for use in interventions, and be used to support peer support workers in recounting their own recovery narratives in ways which are maximally beneficial to others

    The Influence of Curator Goals on Collections of Lived Experience Narratives: A Qualitative Study

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    Objective: The aim of this study was to investigate how curator goals influence the design of curation processes for collections of mental health lived experience narratives. The objectives were (1) to characterize the goals of a range of curators of existing collections, and (2) to identify specific working practices impacted by these goals.Research Design and Methods: Thirty semi-structured interviews were conducted with a purposive sample of curators of collections of lived experience narratives. Thematic analysis was conducted. Goals and impacts on working practice were tabulated, and narrative summaries were constructed to describe the relation between the two.Results: Curators interviewed were from seven countries (Brazil, Canada, Hong Kong, India, Italy, UK, USA), and 60% had lived experience of mental health service usage. Participants discussed eight goals that inspired their work: fighting stigma, campaigning for change in service provision, educating about mental health and recovery, supporting others in their recovery journey, critiquing psychiatry, influencing policy, marketing health services, and reframing mental illness. These goals influenced how decisions were made about inclusion of narratives, editing of narrative content, withdrawal rights, and anonymization. Conclusions: Our work will support the development of curatorship as a professional practice by shaping training for curators, helping curators reflect on the outcomes they would like to achieve, and helping individuals planning a collection to reflect on their motivations. We argue that transparency is an essential orientation for curators. Transparency allows narrators to make an informed choice about donating a narrative. It allows policy makers to understand the influences on a collection and hence treat it as a source of collective evidence

    Post-traumatic growth in psychosis: a systematic review and narrative synthesis

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    Background and objective: People with psychosis report experiences of highly traumatic events. Positive change or post-traumatic growth (PTG) can occur as a result of traumatic experiences. Yet there is limited attention on PTG in psychosis, possibly due to the negative impact of psychotic symptoms on functioning and quality of life. The aim of this review was to identify significant correlates and mediators of PTG in psychosis, and to develop a conceptual framework synthesising facilitators of PTG in psychosis. Method: Ten electronic databases were searched in seven languages, and five journals and grey literature were searched in English. Quantitative studies were eligible if examining correlates, mediators, or the temporal relationship between PTG and one or more variables. Qualitative studies were eligible if describing PTG arising from experiences of psychosis. Findings from quantitative papers were grouped by analysis method, with significant correlates, mediators, and temporal relationships descriptively reported upon. Narrative synthesis was conducted on findings in qualitative papers. Results: Thirty-seven papers were included. Significant correlates and mediators of PTG were identified. Mediators of PTG in psychosis included meaning in life, coping self-efficacy, core beliefs, and self-reported recovery. No studies describing the temporal relationship between PTG and psychosis were identified. The narrative synthesis identified seven facilitators of PTG in psychosis: Personal identity and strength, Receiving support, Opportunities and possibilities, Strategies for coping, Perspective shift, Emotional experience, and Relationships, giving the acronym PROSPER. Conclusions: Individuals with psychosis can be supported to grow from traumatic experiences. Clinicians can support PTG through the provision of trauma-informed care that supports positively valued identity changes. For researchers, the findings provide an evidence-based theoretical framework for conceptualising PTG, which can be validated through longitudinal cohort studies and underpin the development of new clinical interventions

    Typology of content warnings and trigger warnings: systematic review

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    Content and trigger warnings give information about the content of material prior to receiving it. Different typologies of content warnings have emerged across multiple sectors, including health, social media, education and entertainment. Benefits arising from their use are contested, with recent empirical evidence from educational sectors suggesting they may raise anxiety and reinforce the centrality of trauma experience to identity, whilst benefits relate to increased individual agency in making informed decisions about engaging with content. Research is hampered by the absence of a shared inter-sectoral typology of warnings. The aims of this systematic review are to develop a typology of content warnings and to identify the contexts in which content warnings are used. The review was pre-registered (ID: CRD42020197687, URL: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020197687) and used five sources: electronic databases covering multiple sectors (n = 19); table of contents from multi-sectoral journals (n = 5), traditional and social media websites (n = 53 spanning 36 countries); forward and backward citation tracking; and expert consultation (n = 15). In total, 6,254 documents were reviewed for eligibility and 136 documents from 32 countries were included. These were synthesised to develop the Narrative Experiences Online (NEON) content warning typology, which comprises 14 domains: Violence, Sex, Stigma, Disturbing content, Language, Risky behaviours, Mental health, Death, Parental guidance, Crime, Abuse, Socio-political, Flashing lights and Objects. Ten sectors were identified: Education, Audio-visual industries, Games and Apps, Media studies, Social sciences, Comic books, Social media, Music, Mental health, and Science and Technology. Presentation formats (n = 15) comprised: education materials, film, games, websites, television, books, social media, verbally, print media, apps, radio, music, research, DVD/video and policy document. The NEON content warning typology provides a framework for consistent warning use and specification of key contextual information (sector, presentation format, target audience) in future content warning research, allowing personalisation of content warnings and investigation of global sociopolitical trends over time

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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