379 research outputs found

    Hormonal Physiology of Childbearing: Evidence and Implications for Women, Babies, and Maternity Care

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    This report synthesizes evidence about innate hormonally-mediated physiologic processes in women and fetuses/newborns during childbearing, and possible impacts of common maternity care practices and interventions on these processes, focusing on four hormone systems that are consequential for childbearing. Core hormonal physiology principles reveal profound interconnections between mothers and babies, among hormone systems, and from pregnancy through to the postpartum and newborn periods. Overall, consistent and coherent evidence from physiologic understandings and human and animal studies finds that the innate hormonal physiology of childbearing has significant benefits for mothers and babies. Such hormonally-mediated benefits may extend into the future through optimization of breastfeeding and maternal-infant attachment. A growing body of research finds that common maternity care interventions may disturb hormonal processes, reduce their benefits, and create new challenges. Developmental and epigenetic effects are biologically plausible but poorly studied. The perspective of hormonal physiology adds new considerations for benefit-harm assessments in maternity care, and suggests new research priorities, including consistently measuring crucial hormonally-mediated outcomes that are frequently overlooked. Current understanding suggests that safely avoiding unneeded maternity care interventions would be wise, as supported by the Precautionary Principle. Promoting, supporting, and protecting physiologic childbearing, as far as safely possible in each situation, is a low-technology health and wellness approach to the care of childbearing women and their fetuses/newborns that is applicable in almost all maternity care settings

    The Effects of Video Instruction Versus Verbal Instruction on High Intensity Interval Exercise Performance: A Pilot Analysis

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    It has been indicated that music and motivational videos can have a positive impact on high-intensity treadmill performance in trained athletes. It has also been shown that live or recorded video exercise instructions have an overall positive effect on exercise performance accuracy in upper extremity exercises compared to written or verbal instructions in adults with no shoulder pathologies. It is unclear whether exercise instructions given via a home workout video has any effects on non-equipment based high-intensity interval exercise performance. Purpose: The purpose of this study was to determine whether exercising along with pre-recorded video instructions positively impacts overall exercise performance in a single bout of Tabata exercise compared to verbal and handout instructions alone. Methods: In this cross-over design, 8 (2F; 6M) sedentary, college-aged (171.5±40.7 lbs; 67.6±3in; 21.3±1.5yrs) individuals participated in two randomized intervention groups: 1) Tabata with video instructions on a computer screen (V) and 2) Tabata without video instruction (NV). The Tabata workout consisted of five total sessions. Each session was composed of two rounds, with each round containing four exercises each lasting 20 seconds followed by 10 seconds of rest. Following the completion of a session, participants were given a 60 second rest period. The total duration of the exercise was 25 minutes. During the recovery period, the participants’ heart rate (HR) and ratings of perceived exertion (RPE) were recorded. Prior(pre) and immediately following the completion of exercise(post), participants were given the felt arousal scale (FAS) and the 10-centimeter visual analog fatigue scale (FS) to assess participants arousal and overall fatigue. Significant differences (p\u3c0.05) for average RPE for each trial along with the pre and post FAS and FS for each trial was determined using a Wilcoxon Signed-Rank test. Significant differences between HR were analyzed using a Student\u27s T-test (p\u3c0.05). Results: The results of the dependent samples Wilcoxon test did not reveal any significant differences between NVFASPre and VFASpre (p=0.783), NVFASpost and VFASpost (p=0.71), NVFSpre and VFSpre (p=.401), NVFSpost and VFSpost (p=0.401) and NVRPE and VRPE (p=0.779). The student\u27s t-test also did not reveal any significant differences between NVHR and VHR (174.3 ± 18.4 & 174.3 ± 13.2 BPM; p=.359). Conclusion: The findings of this study suggest that there was no significant difference in exercise performance, arousal, intensity, and fatigue between instructions given visually or verbally. However, the preference of the participants for instruction was verbal rather than visual. Comments from the participants included that the person demonstrating the exercises in the video reduced their self-efficacy, because they could not keep up. Limitations of this study were the small sample size, not counting the number of repetitions for each exercise, and population of the participants. Future research should address these limitations

    Structure-guided design and optimization of small molecules targeting the protein-protein interaction between the von hippel-lindau (VHL) E3 ubiquitin ligase and the hypoxia inducible factor (HIF) alpha subunit with in vitro nanomolar affinities

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    E3 ubiquitin ligases are attractive targets in the ubiquitin-proteasome system, however, the development of small-molecule ligands has been rewarded with limited success. The von Hippel-Lindau protein (pVHL) is the substrate recognition subunit of the VHL E3 ligase that targets HIF-1α for degradation. We recently reported inhibitors of the pVHL:HIF-1α interaction, however they exhibited moderate potency. Herein, we report the design and optimization, guided by X-ray crystal structures, of a ligand series with nanomolar binding affinities

    Dystrophin Gene Mutation Location and the Risk of Cognitive Impairment in Duchenne Muscular Dystrophy

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    Contains fulltext : 88828.pdf (publisher's version ) (Open Access)BACKGROUND: A significant component of the variation in cognitive disability that is observed in Duchenne muscular dystrophy (DMD) is known to be under genetic regulation. In this study we report correlations between standardised measures of intelligence and mutational class, mutation size, mutation location and the involvement of dystrophin isoforms. METHODS AND RESULTS: Sixty two male subjects were recruited as part of a study of the cognitive spectrum in boys with DMD conducted at the Sydney Children's Hospital (SCH). All 62 children received neuropsychological testing from a single clinical psychologist and had a defined dystrophin gene (DMD) mutation; including DMD gene deletions, duplications and DNA point mutations. Full Scale Intelligence Quotients (FSIQ) in unrelated subjects with the same mutation were found to be highly correlated (r = 0.83, p = 0.0008), in contrast to results in previous publications. In 58 cases (94%) it was possible to definitively assign a mutation as affecting one or more dystrophin isoforms. A strong association between the risk of cognitive disability and the involvement of groups of DMD isoforms was found. In particular, improvements in the correlation of FSIQ with mutation location were identified when a new classification system for mutations affecting the Dp140 isoform was implemented. SIGNIFICANCE: These data represent one of the largest studies of FSIQ and mutational data in DMD patients and is among the first to report on a DMD cohort which has had both comprehensive mutational analysis and FSIQ testing through a single referral centre. The correlation between FSIQ results with the location of the dystrophin gene mutation suggests that the risk of cognitive deficit is a result of the cumulative loss of central nervous system (CNS) expressed dystrophin isoforms, and that correct classification of isoform involvement results in improved estimates of risk

    High blood pressure and risk of dementia : a two-sample Mendelian randomization study in the UK biobank

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    This work was supported by Janssen Research and Development , LLC (of Johnson & Johnson).Background: Findings from randomized controlled trials have yielded conflicting results on the association between blood pressure (BP) and dementia traits. We tested the hypothesis that a causal relationship exists between systolic BP (SBP) and/or diastolic BP (DBP) and risk of Alzheimer's disease (AD). Methods: We performed a generalized summary Mendelian randomization (GSMR) analysis using summary statistics of a genome-wide association study meta-analysis of 299,024 individuals of SBP or DBP as exposure variables against three different outcomes: 1) AD diagnosis (International Genomics of Alzheimer's Project), 2) maternal family history of AD (UK Biobank), and 3) paternal family history of AD (UK Biobank). Finally, a combined meta-analysis of 368,440 individuals that included these three summary statistics was used as final outcome. Results: GSMR applied to the International Genomics of Alzheimer's Project dataset revealed a significant effect of high SBP lowering the risk of AD (βGSMR = −0.19, p =.04). GSMR applied to the maternal family history of AD UK Biobank dataset (SBP [βGSMR = −0.12, p =.02], DBP [βGSMR = −0.10, p =.05]) and to the paternal family history of AD UK Biobank dataset (SBP [βGSMR = −0.16, p =.02], DBP [βGSMR = −0.24, p = 7.4 × 10−4]) showed the same effect. A subsequent combined meta-analysis confirmed the overall significant effect for the other SBP analyses (βGSMR = −0.14, p =.03). The DBP analysis in the combined meta-analysis also confirmed a DBP effect on AD (βGSMR = −0.14, p =.03). Conclusions: A causal effect exists between high BP and a reduced late-life risk of AD. The results were obtained through careful consideration of confounding factors and the application of complementary MR methods on independent cohorts.Peer reviewe

    Beyond synthesis: Augmenting systematic review procedures with practical principles to optimise impact and uptake in educational policy and practice

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    Whilst systematic reviews, meta-analyses and other forms of synthesis are often constructed as sitting proudly atop the hierarchy of research evidence, their limited impact on educational policy and practice has been criticised. In this article, we analyse why systematic reviews do not benefit users of evidence more consistently and suggest how review teams can optimise the impact of their work. We introduce the Beyond Synthesis Impact Chain (BSIC), an integrated framework of practical strategies for enhancing the impact of systematic reviews. Focusing upon examples from health professions education, we propose that review teams can optimise the impact of their work by employing strategies that 1) focus on practical problems and mindful planning in collaboration with users; 2) ensure reviews are relevant and syntheses reflexively account for users’ needs; and 3) couch reports in terms that resonate with users’ needs and increase access through targeted and strategic dissemination. We argue that combining practical principles with robust and transparent procedures can purposefully account for impact, and foster the uptake of review evidence in educational policy and practice. For systematic review teams, this paper offers strategies for enhancing the practical utility and potential impact of systematic reviews and other forms of synthesis

    DNA binding and unwinding by Hel308 helicase requires dual functions of a winged helix domain

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    Hel308 helicases promote genome stability linked to DNA replication in archaea, and have homologues in metazoans. In the crystal structure of archaeal Hel308 bound to a tailed DNA duplex, core helicase domains encircle single-stranded DNA (ssDNA) in a “ratchet” for directional translocation. A winged helix domain (WHD) is also present, but its function is mysterious. We investigated the WHD in full-length Hel308, identifying that mutations in a solvent exposed α-helix resulted in reduced DNA binding and unwinding activities. When isolated from the rest of Hel308, the WHD protein alone bound to duplex DNA but not ssDNA, and DNA binding by WHD protein was abolished by the same mutations as were analyzed in full-length Hel308. Isolated WHD from a human Hel308 homologue (HelQ) also bound to duplex DNA. By disrupting the interface between the Hel308 WHD and a RecA-like domain, a topology typical of Ski2 helicases, we show that this is crucial for ATPase and helicase activities. The data suggest a model in which the WHD promotes activity of Hel308 directly, through binding to duplex DNA that is distinct from ssDNA binding by core helicase, and indirectly through interaction with the RecA-like domain. We propose how the WHD may contribute to ssDNA translocation, resulting in DNA helicase activity or in removal of other DNA bound proteins by “reeling” ssDNA

    Glucocorticoids regulate mitochondrial fatty acid oxidation in fetal cardiomyocytes

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    Abstract: The late gestational rise in glucocorticoids contributes to the structural and functional maturation of the perinatal heart. Here, we hypothesized that glucocorticoid action contributes to the metabolic switch in perinatal cardiomyocytes from carbohydrate to fatty acid oxidation. In primary mouse fetal cardiomyocytes, dexamethasone treatment induced expression of genes involved in fatty acid oxidation and increased mitochondrial oxidation of palmitate, dependent upon a glucocorticoid receptor (GR). Dexamethasone did not, however, induce mitophagy or alter the morphology of the mitochondrial network. In vivo, in neonatal mice, dexamethasone treatment induced cardiac expression of fatty acid oxidation genes. However, dexamethasone treatment of pregnant C57Bl/6 mice at embryonic day (E)13.5 or E16.5 failed to induce fatty acid oxidation genes in fetal hearts assessed 24 h later. Instead, at E17.5, fatty acid oxidation genes were downregulated by dexamethasone, as was GR itself. PGC-1α, required for glucocorticoid-induced maturation of primary mouse fetal cardiomyocytes in vitro, was also downregulated in fetal hearts at E17.5, 24 h after dexamethasone administration. Similarly, following a course of antenatal corticosteroids in a translational sheep model of preterm birth, both GR and PGC-1α were downregulated in heart. These data suggest that endogenous glucocorticoids support the perinatal switch to fatty acid oxidation in cardiomyocytes through changes in gene expression rather than gross changes in mitochondrial volume or mitochondrial turnover. Moreover, our data suggest that treatment with exogenous glucocorticoids may interfere with normal fetal heart maturation, possibly by downregulating GR. This has implications for clinical use of antenatal corticosteroids when preterm birth is considered a possibility. Key points: Glucocorticoids are steroid hormones that play a vital role in late pregnancy in maturing fetal organs, including the heart. In fetal cardiomyocytes in culture, glucocorticoids promote mitochondrial fatty acid oxidation, suggesting they facilitate the perinatal switch from carbohydrates to fatty acids as the predominant energy substrate. Administration of a synthetic glucocorticoid in late pregnancy in mice downregulates the glucocorticoid receptor and interferes with the normal increase in genes involved in fatty acid metabolism in the heart. In a sheep model of preterm birth, antenatal corticosteroids (synthetic glucocorticoid) downregulates the glucocorticoid receptor and the gene encoding PGC-1α, a master regulator of energy metabolism. These experiments suggest that administration of antenatal corticosteroids in anticipation of preterm delivery may interfere with fetal heart maturation by downregulating the ability to respond to glucocorticoids

    Hematopoietic reconstitution by multipotent adult progenitor cells: precursors to long-term hematopoietic stem cells

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    For decades, in vitro expansion of transplantable hematopoietic stem cells (HSCs) has been an elusive goal. Here, we demonstrate that multipotent adult progenitor cells (MAPCs), isolated from green fluorescent protein (GFP)-transgenic mice and expanded in vitro for >40–80 population doublings, are capable of multilineage hematopoietic engraftment of immunodeficient mice. Among MAPC-derived GFP+CD45.2+ cells in the bone marrow of engrafted mice, HSCs were present that could radioprotect and reconstitute multilineage hematopoiesis in secondary and tertiary recipients, as well as myeloid and lymphoid hematopoietic progenitor subsets and functional GFP+ MAPC-derived lymphocytes that were functional. Although hematopoietic contribution by MAPCs was comparable to control KTLS HSCs, approximately 103-fold more MAPCs were required for efficient engraftment. Because GFP+ host-derived CD45.1+ cells were not observed, fusion is not likely to account for the generation of HSCs by MAPCs
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