196 research outputs found

    Cervelleite, Ag4TeS: solution and description of the crystal structure

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    Copyright: Springer-Verlag Wien 2015. This is the final, post refereeing version. You are advised to consult the publisher's version if you wish to cite from it, http://link.springer.com/article/10.1007%2Fs00710-015-0384-

    The SWR1 Histone Replacement Complex Causes Genetic Instability and Genome-Wide Transcription Misregulation in the Absence of H2A.Z

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    The SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription, gene silencing, chromosome segregation and DNA repair. Here we show that genetic instability, sensitivity to drugs impairing different cellular processes and genome-wide transcriptional misregulation in htz1Δ can be partially or totally suppressed if SWR1 is not formed (swr1Δ), if it forms but cannot bind to chromatin (swc2Δ) or if it binds to chromatin but lacks histone replacement activity (swc5Δ and the ATPase-dead swr1-K727G). These results suggest that in htz1Δ the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter. This would impair transcription and, either directly or indirectly, other cellular processes. Specifically, we show that in htz1Δ, the SWR1 complex causes an accumulation of recombinogenic DNA damage by a mechanism dependent on phosphorylation of H2A at Ser129, a modification that occurs in response to DNA damage, suggesting that the SWR1 complex impairs the repair of spontaneous DNA damage in htz1Δ. In addition, SWR1 causes DSBs sensitivity in htz1Δ; consistently, in the absence of Htz1 the SWR1 complex bound near an endonuclease HO-induced DSB at the mating-type (MAT) locus impairs DSB-induced checkpoint activation. Our results support a stepwise mechanism for the replacement of H2A with Htz1 and demonstrate that a tight control of this mechanism is essential to regulate chromatin dynamics but also to prevent the deleterious consequences of an incomplete nucleosome remodelling

    Survival benefits of statins for primary prevention: a cohort study

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    Objectives: Estimate the effect of statin prescription on mortality in the population of England and Wales with no previous history of cardiovascular disease.  Methods: Primary care records from The Health Improvement Network 1987-2011 were used.Four cohorts of participants aged 60, 65, 70, or 75 years at baseline included 118,700,199,574, 247,149, and 194,085 participants; and 1.4, 1.9, 1.8, and 1.1 million person-years of data, respectively. The exposure was any statin prescription at any time before the participant reached the baseline age (60, 65, 70 or 75) and the outcome was all-cause mortality at any age above the baseline age. The hazard of mortality associated with statin prescription was calculated by Cox's proportional hazard regressions, adjusted for sex, year of birth, socioeconomic status, diabetes,antihypertensive medication, hypercholesterolaemia, body mass index, smoking status, and general practice. Participants were grouped by QRISK2 baseline risk of afirst cardiovascular event in the next ten years of <10%, 10-19%, or ≥20%.  Results: There was no reduction in all-cause mortality for statin prescription initiated in participants with a QRISK2 score <10% at any baseline age, or in participants aged 60at baseline in any risk group. Mortality was lower in participants with a QRISK2 score≥20% if statin prescription had been initiated by age 65 (adjusted hazard ratio (HR)0.86 (0.79-0.94)), 70 (HR 0.83 (0.79-0.88)), or 75 (HR 0.82 (0.79-0.86)). Mortality reduction was uncertain with a QRISK2 score of 10-19%: the HR was 1.00 (0.91-1.11)for statin prescription by age 65, 0.89 (0.81-0.99) by age 70, or 0.79 (0.52-1.19) by age75.  Conclusions: The current internationally recommended thresholds for statin therapy for primary prevention of cardiovascular disease in routine practice may be too low and may lead to overtreatment of younger people and those at low risk

    Environmental enrichment intervention for Rett syndrome: An individually randomised stepped wedge trial

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    Background: Rett syndrome is caused by a pathogenic mutation in the MECP2 gene with major consequences for motor and cognitive development. One of the effects of impaired MECP2 function is reduced production of Brain Derived Neurotrophic Factor (BDNF), a protein required for normal neuronal development. When housed in an enriched environment, MECP2 null mice improved motor abilities and increased levels of BDNF in the brain. We investigated the effects of environmental enrichment on gross motor skills and blood BDNF levels in girls with Rett syndrome. Methods: A genetically variable group of 12 girls with a MECP2 mutation and younger than 6 years participated in a modified individually randomised stepped wedge design study. Assessments were conducted on five occasions, two during the baseline period and three during the intervention period. Gross motor function was assessed using the Rett Syndrome Gross Motor Scale (maximum score of 45) on five occasions, two during the baseline period and three during the intervention period. Blood levels of BDNF were measured at the two baseline assessments and at the end of the intervention period. The intervention comprised motor learning and exercise supplemented with social, cognitive and other sensory experiences over a six-month period. Results: At the first assessment, the mean (SD) age of the children was 3 years (1 year 1 month) years ranging from 1 year 6 months to 5 years 2 months. Also at baseline, mean (SD) gross motor scores and blood BDNF levels were 22.7/45 (9.6) and 165.0 (28.8) ng/ml respectively. Adjusting for covariates, the enriched environment was associated with improved gross motor skills (coefficient 8.2, 95%CI 5.1, 11.2) and a 321.4 ng/ml (95%CI 272.0, 370.8) increase in blood BDNF levels after 6 months of treatment. Growth, sleep quality and mood were unaffected. Conclusions: Behavioural interventions such as environmental enrichment can reduce the functional deficit in Rett syndrome, contributing to the evidence-base for management and further understanding of epigenetic mechanisms. Environmental enrichment will be an important adjunct in the evaluation of new drug therapies that use BDNF pathways because of implications for the strengthening of synapses and improved functioning. Trial registration: ACTRN12615001286538

    The timing of ostomy closure in infants with necrotizing enterocolitis: a systematic review

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    Item does not contain fulltextPURPOSE: The optimal timing of ostomy closure is a matter of debate. We performed a systematic review of outcomes of early ostomy closure (EC, within 8 weeks) and late ostomy closure (LC, after 8 weeks) in infants with necrotizing enterocolitis. METHODS: PubMed, EMbase, Web-of-Science, and Cinahl were searched for studies that detailed time to ostomy closure, and time to full enteral nutrition (FEN) or complications after ostomy closure. Patients with Hirschsprung's disease or anorectal malformations were excluded. Analysis was performed using SPSS 17 and RevMan 5. RESULTS: Of 778 retrieved articles, 5 met the inclusion criteria. The median score for study quality was 9 [range 8-14 on a scale of 0 to 32 points (Downs and Black, J Epidemiol Community Health 52:377-384, 1998)]. One study described mean time to FEN: 19.1 days after EC (n = 13) versus 7.2 days after LC (n = 24; P = 0.027). Four studies reported complication rates after ostomy closure, complications occurred in 27% of the EC group versus 23% of the LC group. The combined odds ratio (LC vs. EC) was 1.1 [95% CI 0.5, 2.5]. CONCLUSION: Evidence that supports early or late closure is scarce and the published articles are of poor quality. There is no significant difference between EC versus LC in the complication rate. This systematic review supports neither early nor late ostomy closure

    An experimental study exploring the impact of vignette gender on the quality of university students’ mental health first aid for peers with symptoms of depression

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    Background University students have high rates of depression, and friends are often the most commonly-used source of support for emotional distress in this population. This study aimed to explore students’ ability to provide effective support for their peers with depressive symptoms and the factors influencing the quality of their mental health first aid (MHFA) skills, including students’ gender, course of study, and gender of student experiencing depression. Methods Via an online survey, students at two British universities (N = 483) were quasi-randomly allocated to view a video vignette of either a male or female student depicting symptoms of depression. An open-ended question probed MHFA actions they would take to help the vignette character, which were rated using a standardised scoring scheme based on MHFA guidelines. Results Students reported low MHFA scores (mean 2.89, out of possible 12). The most commonly reported action was provision of support and information, but only eight (1.6 %) students stated an intention to assess risk of harm. Those studying clinically non-relevant degrees with limited mental health content reported poorer MHFA (p = <0.001) and were less confident about their ability to support a friend with depression (p = 0.04). There was no main effect of vignette gender, but within the group of students on non-relevant courses the male vignette received significantly poorer MHFA than the female vignette (p = 0.02). A significant three-way interaction found that male participants studying non-relevant degrees who viewed a male vignette had poorer MHFA compared to females studying non-relevant degrees who viewed the female vignette (p = 0.005). Conclusions Most students lack the necessary MHFA skills to support friends suffering from symptoms of depression, or to help them get appropriate support and prevent risk of harm. Students on courses which do not include mental health related content are particularly ill-equipped to support male students, with male students receiving the poorest quality MHFA from fellow male students on these courses. MHFA training has the potential to improve outcomes for students with depression, and could have a valuable role in reducing the excess risk of harm seen in male students

    Sleep habits and sleep disturbances in Dutch children: a population-based study

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    Sleep disorders can lead to significant morbidity. Information on sleep in healthy children is necessary to evaluate sleep disorders in clinical practice, but data from different societies cannot be simply generalized. The aims of this study were to (1) assess the prevalence of sleep disturbances in Dutch healthy children, (2) describe sleep habits and problems in this population, (3) collect Dutch norm data for future reference, and (4) compare sleep in children from different cultural backgrounds. A population-based descriptive study was conducted using the Children’s sleep habits questionnaire and the sleep self-report. One thousand five hundred seven proxy-reports and 262 self-reports were analyzed. Mean age was 8.5 years (95% confidence interval, 8.4–8.6), 52% were boys. Sleep problems in Dutch children were present in 25%, i.e., comparable to other populations. Sleep habits were age-related. Problem sleepers scored significantly higher on all scales. Correlations between parental and self-assessments were low to moderate. Dutch children had significantly more sleep disturbances than children from the USA and less than Chinese children. Cognitions and attitudes towards what is considered normal sleep seem to affect the appraisal of sleep, this probably accounts partly for cultural differences. For a better understanding of cultural influences on sleep, more information on these determinants and the establishment of cultural norms are mandatory

    The design of a community lifestyle programme to improve the physical and psychological well-being of pregnant women with a BMI of 30 kg/m2 or more

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    <p>Abstract</p> <p>Background</p> <p>Obesity is a global public health issue. Having a BMI of 30 kg/m<sup>2 </sup>or more (classifying a person as obese) at the start of pregnancy is a significant risk factor for maternal and fetal morbidity. There is a dearth of evidence to inform suitable inteventions to support pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more. Here we describe a study protocol to test the feasibility of a variety of potential healthy lifestyle interventions for pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more in a community based programme.</p> <p>Methods/Design</p> <p>Four hundred women will be approached to attend a 10-week community lifestyle programme. The programme will be provided as a supplement to standard antenatal care. The programme is multi-faceted, aimed at equipping participants with the skills and knowledge needed to adopt healthy behaviours. The social (cognitive) learning theory will be used as a tool to encourage behaviour change, the behaviour change techniques are underpinned by five theoretical components; self-efficacy, outcome expectancies, goal setting, feedback and positive reinforcement.</p> <p>The main outcomes are pregnancy weight gain and caesarean section rate. Other important outcomes include clinical outcomes (e.g., birth weight) and psychological outcomes (e.g., well-being). Secondary outcomes include women's experience of pregnancy and health care services, amount of physical activity, food intake and the suitability of the intervention components.</p> <p>A prospective study using quantitative and qualitative methods will inform the feasibility of implementing the community lifestyle programme with pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more. Mixed methods of data collection will be used, including diaries, focus groups/interviews, pedometers, validated and specifically designed questionnaires, a programme register, weight gain during pregnancy and perinatal outcome data.</p> <p>Discussion</p> <p>Findings from this current feasibility study will inform future interventions and NHS services and add to the evidence-base by providing information about the experiences of pregnant women with a BMI of 30 kg/m<sup>2 </sup>or more undertaking a community lifestyle programme. The study will lead on to a randomised control trial of a suitable intervention to improve the pregnancy outcomes of this target group.</p> <p>Trail Registration</p> <p>ISRCTN29860479.</p

    The association of cardioprotective medications with pneumonia-related outcomes

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    Introduction: Little research has examined whether cardiovascular medications, other than statins, are associated with improved outcomes after pneumonia. Our aim was to examine the association between the use of beta-blockers, statins, angiotensin converting enzyme (ACE) inhibitors, and angiotensin II receptor blockers (ARBs) with pneumonia-related outcomes. Materials and Methods: We conducted a retrospective population-based study on male patients ≥65 years of age hospitalized with pneumonia and who did not have pre-existing cardiac disease. Our primary analyses were multilevel regression models that examined the association between cardiovascular medication classes and either mortality or cardiovascular events. Results: Our cohort included 21,985 patients: 22% died within 90 days of admission, and 22% had a cardiac event within 90 days. The cardiovascular medications studied that were associated with decreased 90-day mortality included: statins (OR 0.70, 95% CI 0.63-0.77), ACE inhibitors (OR 0.82, 95% CI 0.74-0.91), and ARBs (OR 0.58, 95% CI 0.44-0.77). However, none of the medications were significantly associated with decreased cardiovascular events. Discussion: While statins, ACE inhibitors, and ARBs, were associated with decreased mortality, there was no significant association with decreased CV events. These results indicate that this decreased mortality is unlikely due to their potential cardioprotective effects

    From the animal house to the field : are there consistent individual differences in immunological profile in wild populations of field voles (Microtus agrestis)?

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    Inbred mouse strains, living in simple laboratory environments far removed from nature, have been shown to vary consistently in their immune response. However, wildlife populations are typically outbreeding and face a multiplicity of challenges, parasitological and otherwise. In this study we seek evidence of consistent difference in immunological profile amongst individuals in the wild. We apply a novel method in this context, using longitudinal (repeated capture) data from natural populations of field voles, Microtus agrestis, on a range of life history and infection metrics, and on gene expression levels. We focus on three immune genes, IFN-γ, Gata3, and IL-10, representing respectively the Th1, Th2 and regulatory elements of the immune response. Our results show that there was clear evidence of consistent differences between individuals in their typical level of expression of at least one immune gene, and at most all three immune genes, after other measured sources of variation had been taken into account. Furthermore, individuals that responded to changing circumstances by increasing expression levels of Gata3 had a correlated increase in expression levels of IFN-γ. Our work stresses the importance of acknowledging immunological variation amongst individuals in studies of parasitological and infectious disease risk in wildlife populations
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