82 research outputs found

    Baboon endogenous virus genome. I. Restriction enzyme map of the unintegrated DNA genome of a primate retrovirus

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    A detailed restriction map was deduced for the genome of an endogenous retrovirus of a higher primate, that of baboon. The cleavage sites for 12 restriction enzymes were mapped. The unintegrated linear viral DNA intermediate that is produced by infection of permissive cells with baboon endogenous virus was isolated. Hybridization with a strong-stop complementary DNA probe demonstrated presence of a terminal repetition in the linear viral DNA. The positions of restriction sites for two particular enzymes, SmaI and XhoI, near each end were consistent with this result and indicated that the length of the repetition is 0.55 +/- 0.01 kilobase. The linear viral DNA had a unique restriction map indicating that it is not a set of random circular permutations of the RNA genome. From hybridization with a 3'-specific probe, the DNA restriction map was aligned relative to the 5'-to-3' orientation of the viral RNA. We observed a minor heterogeneity in a BamHI recognition site 1.95 kilobases from the right end of the linear map

    Reproduction in wild female olive baboons

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    The purpose of this paper is to evaluate several factors that influence female reproduction in a large troop of wild olive baboons ( Papio cynocephalus anubis ) based on 4 consecutive years of demographic data. Interbirth intervals were significantly shorter for females whose infants died before their next conception than for females whose infants survived. High-ranking mothers of surviving infants had significantly shorter birth intervals than comparable low-ranking mothers, independent of maternal age. This occurred mainly because the interval from resumption of cycling to conception was significantly shorter for high-vs. low-ranking females. Dominance rank did not influence sex ratio at birth, infant survival in the first 2 years, or adult female mortality. Age was also significantly related to interbirth intervals, with older females having shorter intervals. Primiparous females had consistently longer reproductive intervals than did multiparous females, but this difference reached statistical significance only for females whose infants died before the next conception. Primiparous females also experienced significantly higher infant mortality. Data on body size and estrous cycle length indicated no differences between high- and low-ranking females. Nutritional and stress-related mechanisms that may underlie the reproductive advantages of high rank are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38425/1/1350190405_ftp.pd

    Competing Life Narratives: Portraits of Vita Sackville-West

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    This article sets out to examine the fraught, often contested relationship between multiple and competing life narratives, taking as its focus the case of Vita Sackville-West and her infamous love affair with Violet Trefusis. Vita wrote her account of this relationship in a short, autobiographical fragment (1920–21), and this text now forms the basis of nearly all subsequent accounts of her life. By examining how Vita's confession has been appropriated and revised by successive generations of the Nicolson family—in Nigel Nicolson's biography of his parents, Portrait of a Marriage (1973) and Adam Nicolson's recent television documentary, Sissinghurst (2009)—this article will identify the relational structures that exist between texts and across different life-writing genres and media. Contemporary studies of life writing and relationality have emphasised the intratextual connections between subjects. By contrast, the example of Vita Sackville-West highlights the importance of intertextuality. This article explores how intertextual relations—the construction of lives in response to extant accounts; the repetition, revision and accumulation of life narratives—has served to sustain an open-ended industry of life writing

    Cortisol and induced cognitive fatigue: Effects on memory activation in healthy males

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    We investigated the relationship between individual differences in acute fatigue and endogenous cortisol changes elicited by the sustained performance of cognitively demanding tasks (fatigue condition). Healthy males provided salivary cortisol measurements and subjective fatigue ratings, and were scanned (functional magnetic resonance imaging) during memory encoding and recognition tasks in fatigue and control conditions. A group of 15 'responders' showed significantly higher cortisol levels in the fatigue condition than 12 'non-responders'. Responders showed higher subjective fatigue and reduced encoding and recognition activation than non-responders in the fatigue condition. An interaction in activation changes in the right hippocampus during encoding reflected decreased activation in responders, but somewhat increased activation in non-responders in the fatigue compared to control condition. Moreover, decreased hippocampal activation in responders was associated with increased subjective fatigue. Findings are consistent with a central role for the hippocampus in differences between responders and non-responders and also implicate the right hippocampus in individual differences in induced cognitive fatigue effects

    Genetic fine mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci.

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    We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct signal mapped predominantly to noncoding sequence, implying that association with T2D is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine mapping implicated rs10830963 as driving T2D association. We confirmed that the T2D risk allele for this SNP increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease

    Gender moderates diurnal cortisol in relation to trauma and PTSD symptoms: A study in Sri Lankan adolescents

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    Trauma exposure and posttraumatic stress disorder (PTSD) have been linked to aspects of diurnal cortisol secretion in adolescents, but little is known about gender differences in these associations. A school-based sample of Sri Lankan adolescents aged 13-16 years took part in this study 4.5 years after the 2004 tsunami had impacted many of their lives to varying degrees. Saliva samples were obtained 4 times a day for 3 days in 84 participants, who also completed measures of lifetime trauma, current stressors, and posttraumatic stress symptoms (PTSS). We used multilevel regression to estimate effects of trauma exposure and symptoms on cortisol level, diurnal slope, and awakening response (CAR). Results indicated higher cortisol in girls and older adolescents. Although trauma, PTSS, and recent PTSD had non-significant main effects, these three variables interacted with gender, with higher cortisol in girls than in similarly traumatized or symptomatic boys. Co-occurrence of internalizing symptoms and PTSS was also associated with higher cortisol. The 28 adolescents with recent PTSD displayed flatter diurnal slopes, reflecting relatively low morning cortisol. Among the 56 trauma-exposed participants, negative trauma appraisals were associated with higher cortisol. Girls were more likely than boys to display elevated cortisol in relation to re-experiencing and hyperarousal symptoms. In contrast to significant findings for cortisol level and diurnal slope, the CAR showed no association with either trauma or PTSS, irrespective of gender. Findings, viewed in light of normative gender differences in HPA activity during adolescence, can contribute to understanding heightened female vulnerability to posttraumatic stress disorder

    Negative Trauma Appraisals and PTSD Symptoms in Sri Lankan Adolescents

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    The cognitive model posits that negative appraisals play an important role in posttraumatic stress disorder, in children as well as in adults. This study examined correlates of negative appraisals in relation to trauma exposure and their relationship to posttraumatic stress symptoms (PTSS) in 414 Sri Lankan adolescents, aged 12 to 16, living in areas impacted in varying degrees by the 2004 tsunami. In 2008, participants completed measures of negative appraisals, lifetime traumatic events, posttraumatic stress symptoms, internalizing symptoms, ongoing adversity, and social support. The majority (70 %) of the participants reported multiple traumatic events; 25 % met DSM-IV criteria for full or partial PTSD. Adolescents who had experienced more severe events, abusive events, greater cumulative trauma, or greater current adversity reported more negative appraisals. In regression analyses controlling for known risk factors such as female gender, cumulative trauma, ongoing adversity, and low social support, negative appraisals were the best predictor of PTSS, explaining 22 % of the variance. This relationship appeared specific to PTSS, as negative appraisals did not predict internalizing symptoms. Findings confirm the link between negative cognitions concerning traumatic events and persistent PTSS in adolescents, but longitudinal studies are needed to determine whether appraisals contribute to symptom maintenance over time

    Levels and variability of daily life cortisol secretion in major depression

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    Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is an important feature of major depressive disorder (MDD), but relatively little attention has been given to within-person variability of hormone secretion over time. Because most studies have been conducted in hospital settings, little information is available about naturally occurring patterns of cortisol secretion throughout the day in depressed outpatients. Multiple salivary cortisol samples were obtained over a 6-day period from 47 outpatients with MDD and 39 healthy controls in their everyday environment. We used multilevel regression analysis to estimate the effects of MDD and associated clinical characteristics on cortisol levels and intraindividual variability. Although more severe symptoms were associated with small elevations in cortisol levels, we found no clear evidence for hypercortisolism in the MDD group as a whole. However, cortisol output in MDD outpatients was less stable from sample to sample, as evidenced by a significantly lower autocorrelation than that observed in controls. Secretory patterns were particularly erratic in patients with more severe or recurrent episodes. Findings suggest that erratic cortisol secretion may be a more characteristic feature of HPA axis dysregulation in MDD than hypercortisolism, especially in outpatient populations
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