9,755 research outputs found

    Impact of exogenous gonadotropin stimulation on circulatory and follicular fluid cytokine profiles.

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    Background. The natural cycle is the prototype to which we aspire to emulate in assisted reproduction techniques. Increasing evidence is emerging that controlled ovarian hyperstimulation (COH) with exogenous gonadotropins may be detrimental to oogenesis, embryo quality, and endometrial receptivity. This research aimed at assessing the impact of COH on the intrafollicular milieu by comparing follicular fluid (FF) cytokine profiles during stimulated in vitro fertilization (IVF) and modified natural cycle (MNC) IVF. Methods. Ten women undergoing COH IVF and 10 matched women undergoing MNC IVF were recruited for this pilot study. 40 FF cytokine concentrations from individual follicles and plasma were measured by fluid-phase multiplex immunoassay. Demographic/cycle/cytokine data were compared and correlations between cytokines were computed. Results. No significant differences were found between COH and MNC groups for patient and cycle demographics, including outcome. Overall mean FF cytokine levels were higher in the MNC group for 29/40 cytokines, significantly so for leukaemia inhibitory factor and stromal cell-derived factor-1α. Furthermore, FF MNC cytokine correlations were significantly stronger than for COH data. Conclusions. These findings suggest that COH perturbs intrafollicular cytokine networks, in terms of both cytokine levels and their interrelationships. This may impact oocyte maturation/fertilization and embryo developmental competence

    Does aspirin or non-aspirin non-steroidal anti-inflammatory drug use prevent colorectal cancer in inflammatory bowel disease?

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    AIM: To determine whether aspirin or non-aspirin non-steroidal anti-inflammatory drugs (NA-NSAIDs) prevent colorectal cancer (CRC) in patients with inflammatory bowel disease (IBD). METHODS: We performed a systematic review and meta-analysis. We searched for articles reporting the risk of CRC in patients with IBD related to aspirin or NA-NSAID use. Pooled odds ratios (OR) and 95%CIs were determined using a random-effects model. Publication bias was assessed using Funnel plots and Egger’s test. Heterogeneity was assessed using Cochran’s Q and the I2 statistic. RESULTS: Eight studies involving 14917 patients and 3 studies involving 1282 patients provided data on the risk of CRC in patients with IBD taking NA-NSAIDs and aspirin respectively. The pooled OR of developing CRC after exposure to NA-NSAIDs in patients with IBD was 0.80 (95%CI: 0.39-1.21) and after exposure to aspirin it was 0.66 (95%CI: 0.06-1.39). There was significant heterogeneity (I2 > 50%) between the studies. There was no change in the effect estimates on subgroup analyses of the population studied or whether adjustment or matching was performed. CONCLUSION: There is a lack of high quality evidence on this important clinical topic. From the available evidence NA-NSAID or aspirin use does not appear to be chemopreventative for CRC in patients with IBD

    The Complexity of Drawing Graphs on Few Lines and Few Planes

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    It is well known that any graph admits a crossing-free straight-line drawing in R3\mathbb{R}^3 and that any planar graph admits the same even in R2\mathbb{R}^2. For a graph GG and d{2,3}d \in \{2,3\}, let ρd1(G)\rho^1_d(G) denote the minimum number of lines in Rd\mathbb{R}^d that together can cover all edges of a drawing of GG. For d=2d=2, GG must be planar. We investigate the complexity of computing these parameters and obtain the following hardness and algorithmic results. - For d{2,3}d\in\{2,3\}, we prove that deciding whether ρd1(G)k\rho^1_d(G)\le k for a given graph GG and integer kk is R{\exists\mathbb{R}}-complete. - Since NPR\mathrm{NP}\subseteq{\exists\mathbb{R}}, deciding ρd1(G)k\rho^1_d(G)\le k is NP-hard for d{2,3}d\in\{2,3\}. On the positive side, we show that the problem is fixed-parameter tractable with respect to kk. - Since RPSPACE{\exists\mathbb{R}}\subseteq\mathrm{PSPACE}, both ρ21(G)\rho^1_2(G) and ρ31(G)\rho^1_3(G) are computable in polynomial space. On the negative side, we show that drawings that are optimal with respect to ρ21\rho^1_2 or ρ31\rho^1_3 sometimes require irrational coordinates. - Let ρ32(G)\rho^2_3(G) be the minimum number of planes in R3\mathbb{R}^3 needed to cover a straight-line drawing of a graph GG. We prove that deciding whether ρ32(G)k\rho^2_3(G)\le k is NP-hard for any fixed k2k \ge 2. Hence, the problem is not fixed-parameter tractable with respect to kk unless P=NP\mathrm{P}=\mathrm{NP}

    Aligned Drawings of Planar Graphs

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    Let GG be a graph that is topologically embedded in the plane and let A\mathcal{A} be an arrangement of pseudolines intersecting the drawing of GG. An aligned drawing of GG and A\mathcal{A} is a planar polyline drawing Γ\Gamma of GG with an arrangement AA of lines so that Γ\Gamma and AA are homeomorphic to GG and A\mathcal{A}. We show that if A\mathcal{A} is stretchable and every edge ee either entirely lies on a pseudoline or it has at most one intersection with A\mathcal{A}, then GG and A\mathcal{A} have a straight-line aligned drawing. In order to prove this result, we strengthen a result of Da Lozzo et al., and prove that a planar graph GG and a single pseudoline L\mathcal{L} have an aligned drawing with a prescribed convex drawing of the outer face. We also study the less restrictive version of the alignment problem with respect to one line, where only a set of vertices is given and we need to determine whether they can be collinear. We show that the problem is NP-complete but fixed-parameter tractable.Comment: Preliminary work appeared in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

    Quantum Gravity - Testing Time for Theories

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    The extreme smallness of both the Planck length, on the one side, and the ratio of the gravitational to the electrical forces between, say, two electrons, on the other side has led to a widespread belief that the realm of quantum gravity is beyond terrestrial experiments. A series of classical and quantum arguments are put forward to dispel this view. It is concluded that whereas the smallness of the Planck length and the ratio of gravitational to electrical forces, does play its own essential role in nature, it does not make quantum gravity a science where humans cannot venture to probe her secrets. In particular attention is drawn to the latest neutron and atomic interferometry experiments, and to gravity wave interferometers. The latter, as Giovanni Amelino-Camelia argues [Nature 398, 216 (1999)], can be treated as probes of space-time fuzziness down to Planck length for certain quantum-gravity models

    Colonic lesion characterization in inflammatory bowel disease: A systematic review and meta-analysis

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    Aim: To perform a systematic review and meta-analysis for the diagnostic accuracy of in vivo lesion characterization in colonic inflammatory bowel disease (IBD), using optical imaging techniques, including virtual chro-moendoscopy (VCE), dye-based chromoendoscopy (DBC), magnification endoscopy and confocal laser endomicroscopy (CLE). Methods: We searched Medline, Embase and the Cochrane library. We performed a bivariate meta-analysis to calculate the pooled estimate sensitivities, specificities, positive and negative likelihood ratios (+LHR, -LHR), diagnostic odds ratios (DOR), and area under the SROC curve (AUSROC) for each technology group. A subgroup analysis was performed to investigate differences in real-time non-magnified Kudo pit patterns (with VCE and DBC) and real-time CLE. Results: We included 22 studies [1491 patients; 4674 polyps, of which 539 (11.5%) were neoplastic]. Real-time CLE had a pooled sensitivity of 91% (95%CI: 66%-98%), specificity of 97% (95%CI: 94%-98%), and an AUSROC of 0.98 (95%CI: 0.97-0.99). Magnification endoscopy had a pooled sensitivity of 90% (95%CI: 77%-96%) and specificity of 87% (95%CI: 81%-91%). VCE had a pooled sensitivity of 86% (95%CI: 62%-95%) and specificity of 87% (95%CI: 72%-95%). DBC had a pooled sensitivity of 67% (95%CI: 44%-84%) and specificity of 86% (95%CI: 72%-94%). Conclusion: Real-time CLE is a highly accurate technology for differentiating neoplastic from non-neoplastic lesions in patients with colonic IBD. However, most CLE studies were performed by single expert users within tertiary centres, potentially confounding these results

    Immunoglobulin profile of Nigerian children with Plasmodium falciparum infection

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    The immunoglobulin profiles of 126 Nigerian children infected with Plasmodium falciparum in their peripheral blood were investigated. The mean malarial parasitaemia was 4699.17 ± 3695.2 ìl. The meanimmunoglobulin profile of these infected children were 2.68 ± 0.019 mg/dl for IgA, 0.031 ± 0.01 mg/dl for IgD, 1358.29 ± 123.57 ng/dl for IgE, 19.09 ± 1.27 mg/dl for IgG and 2.80 ± 0.57 mg/dl for IgM. Therelationship between the IgD and IgE were positively correlated with the ages of the volunteers at (r = 0.89 and r = 0.97, respectively). The levels of IgA, IgG and IgM were negatively correlated with the agesof the infected children (r = -0.96, r = -0.99 and r = -0.85, respectively). The relationship between the level of parasitaemia and IgA, IgD and IgM were negatively correlated (r = -0.82, r = -0.84 and r = -0.82, respectively). IgG correlated positively with the level of malarial parasitaemia (r = 0.99). We deduce that high IgE and low levels of IgA and IgM are associated with the high risk of P. falciparum malaria attack in our community

    General Practitioners' and patients' perceptions towards stratified care: a theory informed investigation

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    Background Stratified primary care involves changing General Practitioners’ (GPs) clinical behaviour in treating patients, away from the current stepped care approach to instead identifying early treatment options that are matched to patients’ risk of persistent disabling pain. This article explores the perspectives of UK-based GPs and patients about a prognostic stratified care model being developed for patients with the five most common primary care musculoskeletal pain presentations. The focus was on views about acceptability, and anticipated barriers and facilitators to the use of stratified care in routine practice. Methods Four focus groups and six semi-structured telephone interviews were conducted with GPs (n = 23), and three focus groups with patients (n = 20). Data were analysed thematically; and identified themes examined in relation to the Theoretical Domains Framework (TDF), which facilitates comprehensive identification of behaviour change determinants. A critical approach was taken in using the TDF, examining the nuanced interrelationships between theoretical domains. Results Four key themes were identified: Acceptability of clinical decision-making guided by stratified care; impact on the therapeutic relationship; embedding a prognostic approach within a biomedical model; and practical issues in using stratified care. Whilst within each theme specific findings are reported, common across themes was the identified relationships between the theoretical domains of knowledge, skills, professional role and identity, environmental context and resources, and goals. Through analysis of these identified relationships it was found that, for GPs and patients to perceive stratified care as being acceptable, it must be seen to enhance GPs’ knowledge and skills, not undermine GPs’ and patients’ respective identities and be integrated within the environmental context of the consultation with minimal disruption. Conclusions Findings highlight the importance of taking into account the context of general practice when intervening to support GPs to make changes to their clinical behaviour. Findings will inform further stages of the research programme; specifically, the intervention format and content of support packages for GPs participating in a future randomised controlled trial (RCT). This study also contributes to the theoretical debate on how best to encourage clinical behaviour change in general practice, and the possible role of the TDF in that process

    A review of implant provision for hypodontia patients within a Scottish referral centre

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    Background: Implant treatment to replace congenitally missing teeth often involves multidisciplinary input in a secondary care environment. High quality patient care requires an in-depth knowledge of treatment requirements. Aim: This service review aimed to determine treatment needs, efficiency of service and outcomes achieved in hypodontia patients. It also aimed to determine any specific difficulties encountered in service provision, and suggest methods to overcome these. Methods: Hypodontia patients in the Unit of Periodontics of the Scottish referral centre under consideration, who had implant placement and fixed restoration, or review completed over a 31 month period, were included. A standardised data collection form was developed and completed with reference to the patient's clinical record. Information was collected with regard to: the indication for implant treatment and its extent; the need for, complexity and duration of orthodontic treatment; the need for bone grafting and the techniques employed and indicators of implant success. Conclusion: Implant survival and success rates were high for those patients reviewed. Incidence of biological complications compared very favourably with the literature
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