330 research outputs found

    Carotenoid fluorescence in Dunaliella salina

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    Dunaliella salina is a halotolerant green alga that is well known for its carotenoid producing capacity. The produced carotenoids are mainly stored in lipid globules. For various research purposes, such as production and extraction kinetics, we would like to determine and/or localise the carotenoid globules in vivo. In this study, we show that the carotenoid-rich globules emit clear green fluorescence, which can be used in, for example, fluorescence microscopy (e.g. CLSM) to obtain pictures of the cells and their carotenoid content

    Statistical methods for adjusting estimates of treatment effectiveness for patient nonadherence in the context of time-to-event outcomes and health technology assessment: A systematic review of methodological papers

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    Introduction. Medication nonadherence can have a significant negative impact on treatment effectiveness. Standard intention-to-treat analyses conducted alongside clinical trials do not make adjustments for nonadherence. Several methods have been developed that attempt to estimate what treatment effectiveness would have been in the absence of nonadherence. However, health technology assessment (HTA) needs to consider effectiveness under real-world conditions, where nonadherence levels typically differ from those observed in trials. With this analytical requirement in mind, we conducted a review to identify methods for adjusting estimates of treatment effectiveness in the presence of patient nonadherence to assess their suitability for use in HTA. Methods. A “Comprehensive Pearl Growing” technique, with citation searching and reference checking, was applied across 7 electronic databases to identify methodological papers for adjusting time-to-event outcomes for nonadherence using individual patient data. A narrative synthesis of identified methods was conducted. Methods were assessed in terms of their ability to reestimate effectiveness based on alternative, suboptimal adherence levels. Results. Twenty relevant methodological papers covering 12 methods and 8 extensions to those methods were identified. Methods are broadly classified into 4 groups: 1) simple methods, 2) principal stratification methods, 3) generalized methods (g-methods), and 4) pharmacometrics-based methods using pharmacokinetics and pharmacodynamics (PKPD) analysis. Each method makes specific assumptions and has associated limitations. Five of the 12 methods are capable of adjusting for real-world nonadherence, with only g-methods and PKPD considered appropriate for HTA. Conclusion. A range of statistical methods is available for adjusting estimates of treatment effectiveness for nonadherence, but most are not suitable for use in HTA. G-methods and PKPD appear to be more appropriate to estimate effectiveness in the presence of real-world adherence

    Process evaluation of appreciative inquiry to translate pain management evidence into pediatric nursing practice

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    Background Appreciative inquiry (AI) is an innovative knowledge translation (KT) intervention that is compatible with the Promoting Action on Research in Health Services (PARiHS) framework. This study explored the innovative use of AI as a theoretically based KT intervention applied to a clinical issue in an inpatient pediatric care setting. The implementation of AI was explored in terms of its acceptability, fidelity, and feasibility as a KT intervention in pain management. Methods A mixed-methods case study design was used. The case was a surgical unit in a pediatric academic-affiliated hospital. The sample consisted of nurses in leadership positions and staff nurses interested in the study. Data on the AI intervention implementation were collected by digitally recording the AI sessions, maintaining logs, and conducting individual semistructured interviews. Data were analysed using qualitative and quantitative content analyses and descriptive statistics. Findings were triangulated in the discussion. Results Three nurse leaders and nine staff members participated in the study. Participants were generally satisfied with the intervention, which consisted of four 3-hour, interactive AI sessions delivered over two weeks to promote change based on positive examples of pain management in the unit and staff implementation of an action plan. The AI sessions were delivered with high fidelity and 11 of 12 participants attended all four sessions, where they developed an action plan to enhance evidence-based pain assessment documentation. Participants labeled AI a 'refreshing approach to change' because it was positive, democratic, and built on existing practices. Several barriers affected their implementation of the action plan, including a context of change overload, logistics, busyness, and a lack of organised follow-up. Conclusions Results of this case study supported the acceptability, fidelity, and feasibility of AI as a KT intervention in pain management. The AI intervention requires minor refinements (e.g., incorporating continued follow-up meetings) to enhance its clinical utility and sustainability. The implementation process and effectiveness of the modified AI intervention require evaluation in a larger multisite study

    Prospective screening study of 0.5 Tesla dedicated magnetic resonance imaging for the detection of breast cancer in young, high-risk women

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    BACKGROUND: Evidence-based screening guidelines are needed for women under 40 with a family history of breast cancer, a BRCA1 or BRCA2 mutation, or other risk factors. An accurate assessment of breast cancer risk is required to balance the benefits and risks of surveillance, yet published studies have used narrow risk assessment schemata for enrollment. Breast density limits the sensitivity of film-screen mammography but is not thought to pose a limitation to MRI, however the utility of MRI surveillance has not been specifically examined before in women with dense breasts. Also, all MRI surveillance studies yet reported have used high strength magnets that may not be practical for dedicated imaging in many breast centers. Medium strength 0.5 Tesla MRI may provide an alternative economic option for surveillance. METHODS: We conducted a prospective, nonrandomized pilot study of 30 women age 25–49 years with dense breasts evaluating the addition of 0.5 Tesla MRI to conventional screening. All participants had a high quantitative breast cancer risk, defined as ≥ 3.5% over the next 5 years per the Gail or BRCAPRO models, and/or a known BRCA1 or BRCA2 germline mutation. RESULTS: The average age at enrollment was 41.4 years and the average 5-year risk was 4.8%. Twenty-two subjects had BIRADS category 1 or 2 breast MRIs (negative or probably benign), whereas no category 4 or 5 MRIs (possibly or probably malignant) were observed. Eight subjects had BIRADS 3 results, identifying lesions that were "probably benign", yet prompting further evaluation. One of these subjects was diagnosed with a stage T1aN0M0 invasive ductal carcinoma, and later determined to be a BRCA1 mutation carrier. CONCLUSION: Using medium-strength MRI we were able to detect 1 early breast tumor that was mammographically undetectable among 30 young high-risk women with dense breasts. These results support the concept that breast MRI can enhance surveillance for young high-risk women with dense breasts, and further suggest that a medium-strength instrument is sufficient for this application. For the first time, we demonstrate the use of quantitative breast cancer risk assessment via a combination of the Gail and BRCAPRO models for enrollment in a screening trial

    Rituximab in Combination with Corticosteroids for the Treatment of Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis: A NICE Single Technology Appraisal

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    As part of its single technology appraisal (STA) process, the National Institute for Health and Care Excellence (NICE) invited the manufacturer of rituximab (Roche Products) to submit evidence of the clinical and cost effectiveness of rituximab in combination with corticosteroids for treatment of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The School of Health and Related Research Technology Appraisal Group at the University of Sheffield was commissioned to act as the independent Evidence Review Group (ERG). The ERG produced a critical review of the evidence for the clinical and cost effectiveness of the technology, based upon the manufacturer’s submission to NICE. The evidence was derived mainly from a double-blind, phase III, placebo-controlled trial of rituximab in patients with new or relapsed ‘severe’ AAV, which compared a rituximab treatment regimen with an oral cyclophosphamide treatment regimen. Intravenous cyclophosphamide is also commonly used but was not included in the pivotal trial. The evidence showed that rituximab is noninferior to oral cyclophosphamide in terms of induction of remission in adults with AAV and de novo disease, and is superior to oral cyclophosphamide in terms of remission in adults who have relapsed once on cyclophosphamide. The ERG concluded that the results of the manufacturer’s economic evaluation could not be considered robust, because of errors and because the full range of relevant treatment sequences were not modelled. The ERG amended the manufacturer’s model and demonstrated that rituximab was likely to represent a cost-effective addition to the treatment sequence if given after cyclophosphamide treatment

    The pedunculopontine tegmental nucleus and the nucleus basalis magnocellularis: Do both have a role in sustained attention?

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    It is well established that nucleus basalis magnocellularis (NbM) lesions impair performance on tests of sustained attention. Previous work from this laboratory has also demonstrated that pedunculopontine tegmental nucleus (PPTg) lesioned rats make more omissions on a test of sustained attention, suggesting that it might also play a role in mediating this function. However, the results of the PPTg study were open to alternative interpretation. We aimed to resolve this by conducting a detailed analysis of the effects of damage to each brain region in the same sustained attention task used in our previous work. Rats were trained in the task before surgery and post-surgical testing examined performance in response to unpredictable light signals of 1500 ms and 4000 ms duration. Data for PPTg lesioned rats were compared to control rats, and rats with 192 IgG saporin infusions centred on the NbM. In addition to operant data, video data of rats' performance during the task were also analysed

    Global analysis of gene expression in response to L-Cysteine deprivation in the anaerobic protozoan parasite Entamoeba histolytica

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    <p>Abstract</p> <p>Background</p> <p><it>Entamoeba histolytica</it>, an enteric protozoan parasite, causes amebic colitis and extra intestinal abscesses in millions of inhabitants of endemic areas. <it>E. histolytica </it>completely lacks glutathione metabolism but possesses L-cysteine as the principle low molecular weight thiol. L-Cysteine is essential for the structure, stability, and various protein functions, including catalysis, electron transfer, redox regulation, nitrogen fixation, and sensing for regulatory processes. Recently, we demonstrated that in <it>E. histolytica</it>, L-cysteine regulates various metabolic pathways including energy, amino acid, and phospholipid metabolism.</p> <p>Results</p> <p>In this study, employing custom-made Affymetrix microarrays, we performed time course (3, 6, 12, 24, and 48 h) gene expression analysis upon L-cysteine deprivation. We identified that out of 9,327 genes represented on the array, 290 genes encoding proteins with functions in metabolism, signalling, DNA/RNA regulation, electron transport, stress response, membrane transport, vesicular trafficking/secretion, and cytoskeleton were differentially expressed (≥3 fold) at one or more time points upon L-cysteine deprivation. Approximately 60% of these modulated genes encoded proteins of no known function and annotated as hypothetical proteins. We also attempted further functional analysis of some of the most highly modulated genes by L-cysteine depletion.</p> <p>Conclusions</p> <p>To our surprise, L-cysteine depletion caused only limited changes in the expression of genes involved in sulfur-containing amino acid metabolism and oxidative stress defense. In contrast, we observed significant changes in the expression of several genes encoding iron sulfur flavoproteins, a major facilitator super-family transporter, regulator of nonsense transcripts, NADPH-dependent oxido-reductase, short chain dehydrogenase, acetyltransferases, and various other genes involved in diverse cellular functions. This study represents the first genome-wide analysis of transcriptional changes induced by L-cysteine deprivation in protozoan parasites, and in eukaryotic organisms where L-cysteine represents the major intracellular thiol.</p

    Correlation between driving-related skill and alcohol use in young-adults from six European countries: the TEN-D by Night Project

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    <p>Abstract</p> <p>Background</p> <p>Only few studies with small experimental samples investigated the impact of psychoactive substances on driving performance. We conducted a multicenter international cross-sectional study to evaluate the correlation between alcohol use and driving-related skill as measured by brake reaction time (RT).</p> <p>Methods</p> <p>Before and after the entrance into randomly selected recreational sites from six European countries, all subjects aged 16-35 years, owning a driver license, were asked to compile a structured socio-demographic questionnaire and measure RT (SimuNomad3 driving simulator), breath alcohol concentration (BAC; Drager Alcoltest), and drug use (Oratect III saliva test, only at the exit). Mixed regression modeling was used to evaluate the independent association between RT and alcohol concentration or drug use.</p> <p>Results</p> <p>Before the entrance into the recreational site, 4534 subjects completed all assessments and composed the final sample. Their mean age was 23.1 ± 4.2y; 68.3% were males; 54.7% had BAC > 0 g/L (assumed alcoholics); 7.5% declared illegal drug assumption (mostly cannabis). After the exit, 3019 also completed the second assessment: 71.7% showed BAC > 0 g/L. Controlling for age, gender, educational level, occupation, driver license years, and drug use, BAC was positively associated with RT, achieving significance, however, only when BAC was higher than 0.49 g/L. Significant interaction terms were found between BAC and female gender or drug use, with highest RTs (> 1 sec.) recorded among drug users with BAC > = 1 g/L.</p> <p>Conclusions</p> <p>This field study confirms previous experimental data on the negative impact of alcohol use on driving-related skill, supporting regulations and educational campaigns aimed at discouraging driving after consumption of psychoactive substances.</p

    Directed Evaluation of Enterotoxigenic Escherichia coli Autotransporter Proteins as Putative Vaccine Candidates

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    Diarrheal diseases are responsible for more than 1.5 million deaths annually in developing countries. Enterotoxigenic E. coli (ETEC) are among the most common bacterial causes of diarrhea, accounting for an estimated 300,000–500,000 deaths each year, mostly in young children. There unfortunately is not yet a vaccine that can offer sustained, broad-based protection against ETEC. While most vaccine development effort has focused on plasmid-encoded finger-like ETEC adhesin structures known as colonization factors, additional effort is needed to identify conserved target antigens. Epidemiologic studies suggest that immune responses to uncharacterized, chromosomally encoded antigens could contribute to protection resulting from repeated infections. Earlier studies of immune responses to ETEC infection had identified a class of surface-expressed molecules known as autotransporters (AT). Therefore, available ETEC genome sequences were examined to identify conserved ETEC autotransporters not shared by the commensal E. coli HS strain, followed by studies of the immune response to these antigens, and tests of their utility as vaccine components. Two chromosomally encoded ATs, identified in ETEC, but not in HS, were found to be immunogenic and protective in an animal model, suggesting that conserved AT molecules contribute to protective immune responses that follow natural ETEC infection and offering new potential targets for vaccines
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