614 research outputs found

    The Impact of Recent Alcohol Use on Genome Wide DNA Methylation Signatures

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    Chronic alcohol intake is associated with a wide variety of adverse health outcomes including depression, diabetes, and heart disease. Unfortunately, the molecular mechanisms through which these effects are conveyed are not clearly understood. To examine the potential role of epigenetic factors in this process, we examined the relationship of recent alcohol intake to genome wide methylation patterns using the Illumina 450 Methylation Bead Chip and lymphoblast DNA derived from 165 female subjects participating in the Iowa Adoption Studies. We found that the pattern of alcohol use over the 6-months immediately prior to phlebotomy was associated with, severity-dependent changes in the degree of genome wide methylation that preferentially hypermethylate the central portion of CpG islands with methylation at cg05600126, a probe in ABR, and the 5′ untranslated region of BLCAP attaining genome wide significance in two point and sliding window analyses of probe methylation data, respectively. We conclude that recent alcohol use is associated with widespread changes in DNA methylation in women and that further study to confirm these findings and determine their relationship to somatic function are in order

    Quantification and expert evaluation of evidence for chemopredictive biomarkers to personalize cancer treatment.

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    Predictive biomarkers have the potential to facilitate cancer precision medicine by guiding the optimal choice of therapies for patients. However, clinicians are faced with an enormous volume of often-contradictory evidence regarding the therapeutic context of chemopredictive biomarkers.We extensively surveyed public literature to systematically review the predictive effect of 7 biomarkers claimed to predict response to various chemotherapy drugs: ERCC1-platinums, RRM1-gemcitabine, TYMS-5-fluorouracil/Capecitabine, TUBB3-taxanes, MGMT-temozolomide, TOP1-irinotecan/topotecan, and TOP2A-anthracyclines. We focused on studies that investigated changes in gene or protein expression as predictors of drug sensitivity or resistance. We considered an evidence framework that ranked studies from high level I evidence for randomized controlled trials to low level IV evidence for pre-clinical studies and patient case studies.We found that further in-depth analysis will be required to explore methodological issues, inconsistencies between studies, and tumor specific effects present even within high evidence level studies. Some of these nuances will lend themselves to automation, others will require manual curation. However, the comprehensive cataloging and analysis of dispersed public data utilizing an evidence framework provides a high level perspective on clinical actionability of these protein biomarkers. This framework and perspective will ultimately facilitate clinical trial design as well as therapeutic decision-making for individual patients

    Effects of Genotype and Child Abuse on DNA Methylation and Gene Expression at the Serotonin Transporter

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    Altered regulation of the serotonin transporter (SLC6A4) is hypothesized to be a key event in many forms of neuropsychiatric illness, yet our understanding of the molecular mechanisms through which changes in gene function could lead to illness remains incomplete. In prior studies, we and others have demonstrated that methylation of CpG residues in the promoter associated CpG island alters SLC6A4 gene expression, that the extent of that DNA methylation in child abuse is genotype dependent, and that adverse childhood experiences such as child sex abuse are related to methylation. However, we have not examined whether these effects are splice variant specific, whether the association of methylation to gene expression varies as a function of genotype, and whether methylation in other SLC6A4 gene regions are more likely candidates for GxE effects. In the current investigation we measured methylation in lymphoblast DNA from 158 female subjects in the Iowa Adoption Studies at 16 CpG residues spread across the SLC6A4 locus, and analyzed their relationship to gene expression for two SLC6A4 splice variants. Methylation of two CpG residues in the shore of the CpG island (cg22584138 and cg05951817), a location immediately upstream from exon 1A, predicted gene expression for the splice variant containing Exon 1A + 1B. Methylation at two residues in the CpG island itself (cg 25769822 and cg05016953) was associated with total SLC6A4 expression. Examination of these four CpG residues indicated that methylation of cg22584138 was influenced by both genotype and sex abuse, whereas methylation of cg05016953 was influenced only by sex abuse history. Factors influencing methylation at other CpG dinucleotide pairs were not identified. We conclude that methylation effects on transcription may vary as a function of underlying gene motif and splice variant, and that the shore of CpG islands, upstream of TSS, may be of particular interest in examining environmental effects on methylation

    Poor sleep maintenance and subjective sleep quality are associated with postpartum maternal depression symptom severity

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    Women are at increased risk of developing mood disorders during the postpartum period, and poor postpartum sleep may be a modifiable risk factor for the development of depression. This longitudinal study investigated the relationship between sleep variables and postpartum depression symptoms using wrist actigraphy and self-report surveys. Twenty-five healthy primiparous women were recruited from their outpatient obstetricians’ offices from July 2009 through March 2010. Subjects wore wrist actigraphs for 1 week during the third trimester of pregnancy and again during the 2nd, 6th, 10th, and 14th weeks postpartum while completing sleep logs and sleep surveys. Subjective assessments of mood were collected at the end of each actigraph week. Subjective sleep assessments were strongly predictive of depression severity scores as measured by the Edinburgh Postnatal Depression Scale (EPDS) across all weeks (p<0.001). Actigraphic measures of sleep maintenance, such as sleep fragmentation, sleep efficiency, and wake time after sleep onset, were also significantly correlated with EPDS scores postpartum. However, there was no relationship between nocturnal sleep duration and EPDS scores. This study provides additional evidence that poor sleep maintenance as measured by wrist actigraphy, rather than lesser amounts of sleep, is associated with EPDS scores during the postpartum period and that subjective assessments of sleep may be more accurate predictors of postpartum depression symptoms than wrist actigraphy. It also supports the hypothesis that disrupted sleep may contribute to the development and extent of postpartum depression symptoms

    Antenatal depression, treatment with selective serotonin reuptake inhibitors, and neonatal brain structure: A propensity-matched cohort study

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    The aim of this propensity-matched cohort study was to evaluate the impact of prenatal SSRI exposure and a history of maternal depression on neonatal brain volumes and white matter microstructure. SSRI-exposed neonates (n = 27) were matched to children of mothers with no history of depression or SSRI use (n=54). Additionally, neonates of mothers with a history of depression, but no prenatal SSRI exposure (n=41), were matched to children of mothers with no history of depression or SSRI use (n=82). Structural magnetic resonance imaging and diffusion weighted imaging scans were acquired with a 3T Siemens Allegra scanner. Global tissue volumes were characterized using an automatic, atlas-moderated expectation maximization segmentation tool. Local differences in gray matter volumes were examined using deformation-based morphometry. Quantitative tractography was performed using an adaptation of the UNC-Utah NA-MIC DTI framework. SSRI-exposed neonates exhibited widespread changes in white matter microstructure compared to matched controls. Children exposed to a history of maternal depression but no SSRIs showed no significant differences in brain development compared to matched controls. No significant differences were found in global or regional tissue volumes. Additional research is needed to clarify whether SSRIs directly alter white matter development or whether this relationship is mediated by depressive symptoms during pregnancy

    On the rate of quantum ergodicity in Euclidean billiards

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    For a large class of quantized ergodic flows the quantum ergodicity theorem due to Shnirelman, Zelditch, Colin de Verdi\`ere and others states that almost all eigenfunctions become equidistributed in the semiclassical limit. In this work we first give a short introduction to the formulation of the quantum ergodicity theorem for general observables in terms of pseudodifferential operators and show that it is equivalent to the semiclassical eigenfunction hypothesis for the Wigner function in the case of ergodic systems. Of great importance is the rate by which the quantum mechanical expectation values of an observable tend to their mean value. This is studied numerically for three Euclidean billiards (stadium, cosine and cardioid billiard) using up to 6000 eigenfunctions. We find that in configuration space the rate of quantum ergodicity is strongly influenced by localized eigenfunctions like bouncing ball modes or scarred eigenfunctions. We give a detailed discussion and explanation of these effects using a simple but powerful model. For the rate of quantum ergodicity in momentum space we observe a slower decay. We also study the suitably normalized fluctuations of the expectation values around their mean, and find good agreement with a Gaussian distribution.Comment: 40 pages, LaTeX2e. This version does not contain any figures. A version with all figures can be obtained from http://www.physik.uni-ulm.de/theo/qc/ (File: http://www.physik.uni-ulm.de/theo/qc/ulm-tp/tp97-8.ps.gz) In case of any problems contact Arnd B\"acker (e-mail: [email protected]) or Roman Schubert (e-mail: [email protected]

    Megafauna extinction, tree species range reduction, and carbon storage in Amazonian forests

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    During the Late Pleistocene and early Holocene 59 species of South American megafauna went extinct. Their extinction potentially triggered population declines of large-seeded tree species dispersed by the large-bodied frugivores with which they co-evolved, a theory first proposed by Janzen and Martin (1982). We tested this hypothesis using species range maps for 257 South American tree species, comparing 63 species thought to be primarily distributed by megafauna with 194 distributed by other animals. We found a highly significant (p 95% following disperser extinction. A numerical gap dynamic simulations suggests that over a 10 000 yr period following the disperser extinctions, the average convex hull range size of large-seeded tree species decreased by ∼ 31%, while the estimated decrease in population size was ∼ 54%, indicating a likely greater decrease in species population size than indicated by the empirical range patterns. Finally, we found a positive correlation between seed size and wood density of animal-dispersed tree species implying that the Late Pleistocene and early Holocene megafaunal extinctions reduced carbon content in the Amazon by ∼ 1.5 ± 0.7%. In conclusion, we 1) provide some empirical evidence that megafauna distributed fruit species have a smaller mean range size than wind, water or other animal-dispersed species, 2) demonstrate mathematically that such range reductions are expected from megafauna extinctions ca 12 000 yr ago, and 3) illustrate that these extinctions may have reduced the Amazon's carbon storage capacity

    Rate of Chiari I Malformation in Children of Mothers with Depression with and without Prenatal SSRI Exposure

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    Selective serotonin reuptake inhibitors (SSRIs) are frequently prescribed to pregnant women. Therefore, research on in utero exposure to SSRIs can be helpful in informing patients and clinicians. The aim of this retrospective two-cohort study was to determine whether there is a statistically significant increase in Chiari I malformations (CIM) in children exposed to SSRIs during pregnancy. A total of 33 children whose mothers received a diagnosis of depression and took SSRIs during pregnancy (SSRI-exposed cohort) were matched to 66 children with no history of maternal depression and no SSRI exposure. In addition, 30 children whose mothers received a diagnosis of depression, but did not receive antidepressants during pregnancy (history of maternal depression cohort), were matched to 60 children with no history of maternal depression and no SSRI exposure. Main outcome was presence/absence of CIM on MRI scans at 1 and/or 2 years of age. Scans were reviewed by two independent neuroradiologists who were blind to exposure status. The SSRI-exposed children were significantly more likely to be classified as CIM than comparison children with no history of maternal depression and no SSRI exposure (18% vs 2%, p=0.003, OR estimate 10.32, 95% Wald confidence limits 2.04–102.46). Duration of SSRI exposure, SSRI exposure at conception, and family history of depression increased the risk. The history of maternal depression cohort did not differ from comparison children with no history of maternal depression and no SSRI exposure in occurrence of CIM (7% vs 5%, p=0.75, OR estimate 1.44, 95% Wald confidence limits 0.23–7.85). Replication is needed, as is additional research to clarify whether SSRIs directly impact risk for CIM or whether this relationship is mediated by severity of depressive symptoms during pregnancy. We would discourage clinicians from altering their prescribing practices until such research is available

    Forecasting the spread of raccoon rabies using a purpose-specific group decisionmaking process

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    The Centers for Disease Control (CDC) and USDA Wildlife Services (WS) have been involved in an oral rabies vaccination (ORV) program for raccoons (Procyon lotor) that has slowed the westward spread of raccoon rabies. The objective of this study was to forecast the spread of the disease if an ORV zone was not maintained. A group decision-making process was designed to address the forecasting problem and was implemented using a group of 15 experts and 4 support personnel at a meeting at the USDA National Wildlife Research Center. Ten expansion regions were constructed that described the spread of disease at 2-year intervals. This forecast may provide for more accurate cost-benefit analysis of the ORV barrier
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