547 research outputs found

    Inhibitor binding mode and allosteric regulation of Na+-glucose symporters.

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    Sodium-dependent glucose transporters (SGLTs) exploit sodium gradients to transport sugars across the plasma membrane. Due to their role in renal sugar reabsorption, SGLTs are targets for the treatment of type 2 diabetes. Current therapeutics are phlorizin derivatives that contain a sugar moiety bound to an aromatic aglycon tail. Here, we develop structural models of human SGLT1/2 in complex with inhibitors by combining computational and functional studies. Inhibitors bind with the sugar moiety in the sugar pocket and the aglycon tail in the extracellular vestibule. The binding poses corroborate mutagenesis studies and suggest a partial closure of the outer gate upon binding. The models also reveal a putative Na+ binding site in hSGLT1 whose disruption reduces the transport stoichiometry to the value observed in hSGLT2 and increases inhibition by aglycon tails. Our work demonstrates that subtype selectivity arises from Na+-regulated outer gate closure and a variable region in extracellular loop EL5

    Suicidal students' use of and attitudes to primary care prevention services

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    Aim The aims of this study were to improve responses to students in distress and who are feeling suicidal, to help practitioners to increase their responsiveness to those at high risk of suicide and to develop effective responses to those affected by their deaths. The study sought to build a detailed picture of students’ patterns of service use. Background National suicide prevention strategies emphasise that suicide prevention requires the collaboration of a wide range of organisations. Among these, primary care services play a key role in relation to suicide prevention for young people in crisis. Methods This study, undertaken between 2004 and 2007, focused on 20 case studies of student suicide that took place in the United Kingdom between May 2000 and June 2005. It adopted a psychological autopsy approach to learn from a wide range of informants, including parents, friends, university staff and the records of coroners or procurator fiscals. Twenty families gave permission for their son’s or daughter’s death to be included in the study and agreed to participate in the study. Informants were interviewed in person and the data were analysed thematically. Analysis of the case study data suggested that in a number of cases students had failed to engage with services sufficiently early or in sufficient depth. Primary care practitioners need to be proactive in communicating concerns about vulnerable students to student support services. At local levels, collaboration between student support and National Health Service practitioners varied considerably and channels of communication need to be developed

    Infant Hearing Screening 1984 to 1989: The Henry Ford Hospital Experience

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    From 1984 to 1989 the Infant Hearing Screening (IHS) program at Henry Ford Hospital identified 1,300 infants as being at risk for hearing loss. The prevalence of significant sensorineural hearing loss in this sample was 1.4%. Additionally, 80 infants who passed the IHS program and reached 3 years of age were found to have normal hearing sensitivity by conventional audiometric techniques (ie, no false-negative predictions). There were three false-positive predictions. It was discovered that infants of low birthweight (ie, \u3c 1,500 g) were three times more likely to fail IHS than those whose weight exceeded 1,500 g. A higher return rate was found for infants failing an initial hearing screening conducted in the neonatal intensive care unit in comparison to those screened as outpatients one week postdischarge. The sensitivity and specificity of behavioral observation audiometry were 43% and 92%, respectively, when brainstem auditory-evoked potentials was used as the criterion validity measure

    TNF-α Differentially Regulates Cell Cycle Genes In Promyelocytic And Granulocytic HL-60/S4 Cells

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    Tumor necrosis factor alpha (TNF-α) is a potent cytokine involved in systemic inflammation and immune modulation. Signaling responses that involve TNF-α are context dependent and capable of stimulating pathways promoting both cell death and survival. TNF-α treatment has been investigated as part of a combined therapy for acute myeloid leukemia due to its modifying effects on all-trans retinoic acid (ATRA) mediated differentiation into granulocytes. To investigate the interaction between cellular differentiation and TNF-α, we performed RNA-sequencing on two forms of the human HL-60/S4 promyelocytic leukemia cell line treated with TNF-α. The ATRA-differentiated granulocytic form of HL-60/S4 cells had an enhanced transcriptional response to TNF-α treatment compared to the undifferentiated promyelocytes. The observed TNF-α responses included differential expression of cell cycle gene sets, which were generally upregulated in TNF-α treated promyelocytes, and downregulated in TNF-α treated granulocytes. This is consistent with TNF-α induced cell cycle repression in granulocytes and cell cycle progression in promyelocytes. Moreover, we found evidence that TNF-α treatment of granulocytes shifts the transcriptome toward that of a macrophage. We conclude that TNF-α treatment promotes a divergent transcriptional program in promyelocytes and granulocytes. TNF-α promotes cell cycle associated gene expression in promyelocytes. In contrast, TNF-α stimulated granulocytes have reduced cell cycle gene expression, and a macrophage-like transcriptional program

    “It's all the time in my mind”: Facilitators of adherence to antiretroviral therapy in a Tanzanian setting

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    Although HIV-positive patients’ adherence to antiretroviral therapy (ART) is relatively high in African nations, as compared with industrialized nations, few studies have explored why. In the research presented here we aimed to understand the dynamics of good adherence to ART among patients receiving free ART and HIV-related services from a clinic in Arusha, Tanzania. We conducted individual semi-structured interviews with 6 health care providers and 36 patients at the study site. Interviews were conducted in Swahili using interview guides informed by social cognitive theory. All interviews were audio-recorded, transcribed in Kiswahili, translated into English and coded for themes and patterns with Atlas t.i. Of the 36 patients interviewed (mean time on ART 9.8 months; range 1–23 months), 32 reported perfect adherence in the previous month. Self-reported adherence was high despite economic hardship, depression, low rates of HIV disclosure and high perceived HIV-associated stigma. Five factors emerged to explain excellent adherence in the face of such barriers. First, all respondents experienced substantial improvements in their health after starting ART; this supported their confidence in the medication and motivated them to adhere. Second, their perceived need to be able to meet their family responsibilities motivated respondents to stay healthy. Third, respondents developed specific strategies to remember to take pills, particularly routinizing pill-taking by linking it with daily activities or events. Fourth, material and emotional support received from others facilitated adherence. Finally, respondents trusted the advice and instructions of their health care providers, who regularly emphasized adherence. The facilitating factors identified were consistent with the constructs of social cognitive theory and highlighted the importance of interventions that address multiple levels of influence on adherence

    Factors associated with self-reported adherence to antiretroviral therapy in a Tanzanian setting

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    This study aimed to determine the level of antiretroviral (ART) adherence and factors associated with adherence among patients receiving free ART at one clinic in Tanzania. Adult patients were recruited into the cross-sectional study and completed a survey that included self-reported adherence over four days and over one month. Less than 95% adherence on either measure was considered “poor”. Factors associated with adherence in unadjusted analyses (α=0.10) were included in a logistic regression model. 340 patients participated in the study, and 5.9% (20/340) reported poor adherence. The final model found poor adherence associated with: being young (OR=4.03) or old (OR=6.68); having lower perceived quality of patient-provider interaction (OR=2.75); and ever missing a clinic appointment (OR=3.13). Results highlight good adherence, but suggest the importance of addressing: 1) age-specific challenges of adherence through counseling and support; 2) client-focused care and quality of patient-provider interaction; and 3) clinic appointment reminder systems

    Forkhead box O-class 1 and Forkhead box G1 as Prognostic Markers for Bladder Cancer

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    Forkhead box O-class 1 (FOXO1) is a key regulator of glucose homeostasis, cell-cycle progression, and apoptosis. Its functions are modulated by forkhead box G1 (FOXG1), which acts as a transcriptional repressor with oncogenic potential. Real-time PCR and immunohistochemical staining were performed in 174 primary bladder cancer specimens and 21 normal bladder mucosae to evaluate these genes. FOXO1 and FOXG1 mRNA expression in cancer tissues were higher than in normal mucosae (each P<0.001). FOXO1 mRNA levels were significantly higher in samples of non-progressed patients (P<0.001), but FOXG1 were enhanced in those of progressed patients (P=0.019). On univariate analysis, FOXO1 mRNA expression was significantly associated with grade, stage, recurrence, progression and survival (each P<0.05). On multivariate analysis, increased FOXO1 mRNA expression was associated with both reduced disease progression (odds ratio [OR], 0.367; 95% confidence interval [CI], 0.163-0.826, P=0.015) and enhanced disease-free survival (OR, 3.262; 95% CI, 1.361-7.820, P=0.008). At a median follow-up of 33 months (range 2 to 156), the patients with a high FOXO1 mRNA expression had a significantly prolonged survival (P=0.001). Immunohistochemical findings of FOXO1 were generally concordant with mRNA expression levels. In conclusion, FOXO1 may be a promising marker for predicting progression in human bladder cancers

    A pragmatic cluster randomised trial evaluating three implementation interventions

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    Background Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting. Methods A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients' experiences, and stakeholders' experiences of implementation, including influences. ANOVA was used to test differences over time and interventions. Results Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility. Conclusions This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions' impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance. Trial registration ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE

    Cone-Rod Dystrophy Due to Mutations in a Novel Photoreceptor-Specific Homeobox Gene (CRX) Essential for Maintenance of the Photoreceptor

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    Genes associated with inherited retinal degeneration have been found to encode proteins required for phototransduction, metabolism, or structural support of photoreceptors. Here we show that mutations in a novel photoreceptor-specific homeodomain transcription factor gene (CRX) cause an autosomal dominant form of cone-rod dystrophy (adCRD) at the CORD2 locus on chromosome 19q13. In affected members of a CORD2-linked family, the highly conserved glutamic acid at the first position of the recognition helix is replaced by alanine (E80A). In another CRD family, a 1 bp deletion (E168 [delta1 bp]) within a novel sequence, the WSP motif, predicts truncation of the C-terminal 132 residues of CRX. Mutations in the CRX gene cause adCRD either by haploinsufficiency or by a dominant negative effect and demonstrate that CRX is essential for the maintenance of mammalian photoreceptorsThis work was supported by the RP Foundation of Canada (R. R. M.), the Foundation Fighting Blindness (R. R. M. and S. G. J.), the Canadian Genetic Disease Network (R. R. M. and A. D.), the Medical Research Council of Canada (R. R. M.), The Wellcome Trust (043825/Z/95) and the Human Genome Mapping Resource Centre (C. Y. G.-E. and S. S. B.), the Howard Hughes Medical Institute and NIH R01 EY0 8064 (C. L. C.), the Canadian Genome Analysis and Technology Genome Resource Facility (S. W. S. and L.-C. T.), the NIH/NEI (EY05627) (S. G. J.), and the Greek National Scholarship Foundation (M. P.). R. R. M. and L.-C. T. are International Research Scholars of the Howard Hughes Medical Institute

    High-resolution elemental abundance analysis of the open cluster IC 4756

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    We present detailed elemental abundances of 12 subgiants in the open cluster IC 4756 including Na, Al, Mg, Si, Ca, Ti, Cr, Ni, Fe, Zn and Ba. We measure the cluster to have [Fe/H] = -0.01 +/- 0.10. Most of the measured star-to-star [X/H] abundance variation is below sigma < 0.03, as expected from a coeval stellar population preserving natal abundance patterns, supporting the use of elemental abundances as a probe to reconstruct dispersed clusters. We find discrepancies between Cr I and Cr II abundances as well as between Ti I and Ti II abundances, where the ionized abundances are larger by about 0.2 dex. This follows other such studies which demonstrate the effects of overionization in cool stars. IC 4756 are supersolar in Mg, Si, Na and Al, but are solar in the other elements. The fact that IC 4756 is supersolar in some alpha-elements (Mg, Si) but solar in the others (Ca, Ti) suggests that the production of alpha-elements is not simply one dimensional and could be exploited for chemical tagging.Comment: 13 pages, 13 figures, 10 tables, MNRAS (Accepted for publication- 2012 August 25
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