308 research outputs found

    Length heterogeneity at conserved sequence block 2 in human mitochondrial DNA acts as a rheostat for RNA polymerase POLRMT activity

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    The guanine (G)-tract of conserved sequence block 2 (CSB 2) in human mitochondrial DNA can result in transcription termination due to formation of a hybrid G-quadruplex between the nascent RNA and the nontemplate DNA strand. This structure can then influence genome replication, stability and localization. Here we surveyed the frequency of variation in sequence identity and length at CSB 2 amongst human mitochondrial genomes and used in vitro transcription to assess the effects of this length heterogeneity on the activity of the mitochondrial RNA polymerase, POLRMT. In general, increased G-tract length correlated with increased termination levels. However, variation in the population favoured CSB 2 sequences which produced efficient termination while particularly weak or strong signals were avoided. For all variants examined, the 3′ end of the transcripts mapped to the same downstream sequences and were prevented from terminating by addition of the transcription factor TEFM. We propose that CSB 2 length heterogeneity allows variation in the efficiency of transcription termination without affecting the position of the products or the capacity for regulation by TEFM

    Geographic variation and localised clustering of congenital anomalies in Great Britain

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    Background: Environmental pollution as a cause of congenital anomalies is sometimes suspected because of clustering of anomalies in areas of higher exposure. This highlights questions around spatial heterogeneity (clustering) in congenital anomaly rates. If spatial variation is endemic, then any one specific cluster is less remarkable, though the presence of uncontrolled geographically clustered risk factors is suggested. If rates are relatively homogeneous across space other than around specific hazards, then evidence for these hazards causing the clusters is strengthened. We sought to estimate the extent of spatial heterogeneity in congenital anomaly rates in the United Kingdom. Methods: The study population covered about one million births from five registers in Britain from 1991–1999. We estimated heterogeneity across four geographical levels: register area, hospital catchment, electoral ward, and enumeration district, using a negative binomial regression model. We also sought clusters using a circular scan statistic. Results: Congenital anomaly rates clearly varied across register areas and hospital catchments (p 0.2). Adjusting for socioeconomic deprivation and maternal age made little difference to the extent of geographical variation for most congenital anomaly subtypes. The two most significant circular clusters (of four ano-rectal atresias and six congenital heart diseases) contained two or more siblings. Conclusion: The variation in rates between registers and hospital catchment area may have resulted in part from differences in case ascertainment, and this should be taken into account in geographical epidemiological studies of environmental exposures. The absence of evidence for variation below this level should be interpreted cautiously in view of the low power of general heterogeneity tests. Nevertheless, the data suggest that strong localised clusters in congenital anomalies are uncommon, so clusters around specific putative environmental hazards are remarkable when observed. Negative binomial models applied at successive hierarchical levels provide an approach of intermediate complexity to characterising geographical heterogeneity

    Living bioethics, clinical ethics committees and children's consent to heart surgery

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    This discussion paper considers how seldom recognised theories influence clinical ethics committees. A companion paper examined four major theories in social science: positivism, interpretivism, critical theory and functionalism, which can encourage legalistic ethics theories or practical living bioethics, which aims for theory–practice congruence. This paper develops the legalistic or living bioethics themes by relating the four theories to clinical ethics committee members’ reported aims and practices and approaches towards efficiency, power, intimidation, justice, equality and children’s interests and rights. Different approaches to framing ethical questions are also considered. Being aware of the four theories’ influence can help when seeking to understand and possibly change clinical ethics committee routines. The paper is not a research report but is informed by a recent study in two London paediatric cardiac units. Forty-five practitioners and related experts were interviewed, including eight members of ethics committees, about the work of informing, preparing and supporting families during the extended process of consent to children’s elective heart surgery. The mosaic of multidisciplinary teamwork is reported in a series of papers about each profession, including this one on bioethics and law and clinical ethics committees’ influence on clinical practice. The qualitative social research was funded by the British Heart Foundation, in order that more may be known about the perioperative views and needs of all concerned. Questions included how disputes can be avoided, how high ethical standards and respectful cooperation between staff and families can be encouraged, and how minors’ consent or refusal may be respected, with the support of clinical ethics committees

    Letter from R.D. Blackmore, Teddington, England : autograph manuscript signed, 1888 February 21

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    Note in pencil on the top of the letter regarding the location of R. D. Blackmore\u27s gravehttps://repository.wellesley.edu/autographletters/1298/thumbnail.jp

    Letter from R.D. Blackmore, Teddington, London, England, to Edmund Gosse : autograph manuscript signed, 1896 June 17

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    Regarding reproduction of Blackmore\u27s portrait in America contrary to copyright. Written on the back of a typed manuscript letter, signed, from G.P. Putnam\u27s Sons, London, to R.D. Blackmore, June 16, 1896. Written above this typed letter is an autograph manuscript copy, signed, of a letter to from R.D. Blackman, Teddington, to G.P. Putnam\u27s Sons, June 15, 1896https://repository.wellesley.edu/autographletters/1299/thumbnail.jp

    Letter from Robert D. Andrews, Boston, Massachusetts, to Hugh S. Fullerton, New York, New York : typed manuscript signed, 1925 August 19

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    Recommends Nancy Webster for title of Most Interesting Woman. Letterhead: Andrew, Jones, Biscoe & Whitmore Architects.https://repository.wellesley.edu/autographletters/1093/thumbnail.jp

    Towards environmentally sustainable human behaviour: targeting non-conscious and conscious processes for effective and acceptable policies.

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    Meeting climate change targets to limit global warming to 2°C requires rapid and large reductions in demand for products that most contribute to greenhouse gas (GHG) emissions. These include production of bulk materials (e.g. steel and cement), energy supply (e.g. fossil fuels) and animal source foods (particularly ruminants and their products). Effective strategies to meet these targets require transformative changes in supply as well as demand, involving changes in economic, political and legal systems at local, national and international levels, building on evidence from many disciplines. This paper outlines contributions from behavioural science in reducing demand. Grounded in dual-process models of human behaviour (involving non-conscious and conscious processes) this paper considers first why interventions aimed at changing population values towards the environment are usually insufficient or unnecessary for reducing demand although they may be important in increasing public acceptability of policies that could reduce demand. It then outlines two sets of evidence from behavioural science towards effective systems-based strategies, to identify interventions likely to be effective at: (i) reducing demand for products that contribute most to GHG emissions, mainly targeting non-conscious processes and (ii) increasing public acceptability for policy changes to enable these interventions, targeting conscious processes.This article is part of the themed issue 'Material demand reduction'

    Atrioventricular septal defects among infants in Europe: a population-based study of prevalence, associated anomalies, and survival.

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    OBJECTIVE: To describe the epidemiology of chromosomal and non-chromosomal cases of atrioventricular septal defects in Europe. METHODS: Data were obtained from EUROCAT, a European network of population-based registries collecting data on congenital anomalies. Data from 13 registries for the period 2000-2008 were included. RESULTS: There was a total of 993 cases of atrioventricular septal defects, with a total prevalence of 5.3 per 10,000 births (95% confidence interval 4.1 to 6.5). Of the total cases, 250 were isolated cardiac lesions, 583 were chromosomal cases, 79 had multiple anomalies, 58 had heterotaxia sequence, and 23 had a monogenic syndrome. The total prevalence of chromosomal cases was 3.1 per 10,000 (95% confidence interval 1.9 to 4.3), with a large variation between registers. Of the 993 cases, 639 cases were live births, 45 were stillbirths, and 309 were terminations of pregnancy owing to foetal anomaly. Among the groups, additional associated cardiac anomalies were most frequent in heterotaxia cases (38%) and least frequent in chromosomal cases (8%). Coarctation of the aorta was the most common associated cardiac defect. The 1-week survival rate for live births was 94%. CONCLUSION: Of all cases, three-quarters were associated with other anomalies, both chromosomal and non-chromosomal. For infants with atrioventricular septal defects and no chromosomal anomalies, cardiac defects were often more complex compared with infants with atrioventricular septal defects and a chromosomal anomaly. Clinical outcomes for atrioventricular septal defects varied between regions. The proportion of termination of pregnancy for foetal anomaly was higher for cases with multiple anomalies, chromosomal anomalies, and heterotaxia sequence
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