974 resultados para following pregnancy


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Grattan, John and Pyatt, Brian. 'Acid damage to vegetation following the laki fissure eruption in 1783 - an historical review' The Science of the Total Environment. 26 August 1993. 151 pgs 241-247

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Burnley, M., Doust, J. and Jones, A. (2006). Time required for the restoration of normal heavy exercise Vo(2) kinetics following prior heavy exercise. Journal of Applied Physiology. 101(5), pp.1320-1327 RAE2008

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Luis A.J. Mur, I. Edi Santosa, Lucas J.J. Laarhoven, Nicholas J. Holton, Frans J.M. Harren and Aileen R. Smith (2005). Laser photoacoustic detection allows in planta detection of nitric oxide in tobacco following challenge with avirulent and virulent pseudomonas syringae pathovars. Plant Physiology, 138(3), 1247-1258. Sponsorship: BBSRC / EU RAE2008

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A neural model is presented that explains how outcome-specific learning modulates affect, decision-making and Pavlovian conditioned approach responses. The model addresses how brain regions responsible for affective learning and habit learning interact, and answers a central question: What are the relative contributions of the amygdala and orbitofrontal cortex to emotion and behavior? In the model, the amygdala calculates outcome value while the orbitofrontal cortex influences attention and conditioned responding by assigning value information to stimuli. Model simulations replicate autonomic, electrophysiological, and behavioral data associated with three tasks commonly used to assay these phenomena: Food consumption, Pavlovian conditioning, and visual discrimination. Interactions of the basal ganglia and amygdala with sensory and orbitofrontal cortices enable the model to replicate the complex pattern of spared and impaired behavioral and emotional capacities seen following lesions of the amygdala and orbitofrontal cortex.

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Memories in Adaptive Resonance Theory (ART) networks are based on matched patterns that focus attention on those portions of bottom-up inputs that match active top-down expectations. While this learning strategy has proved successful for both brain models and applications, computational examples show that attention to early critical features may later distort memory representations during online fast learning. For supervised learning, biased ARTMAP (bARTMAP) solves the problem of over-emphasis on early critical features by directing attention away from previously attended features after the system makes a predictive error. Small-scale, hand-computed analog and binary examples illustrate key model dynamics. Twodimensional simulation examples demonstrate the evolution of bARTMAP memories as they are learned online. Benchmark simulations show that featural biasing also improves performance on large-scale examples. One example, which predicts movie genres and is based, in part, on the Netflix Prize database, was developed for this project. Both first principles and consistent performance improvements on all simulation studies suggest that featural biasing should be incorporated by default in all ARTMAP systems. Benchmark datasets and bARTMAP code are available from the CNS Technology Lab Website: http://techlab.bu.edu/bART/.

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Pregnancy-Specific Glycoproteins (PSG) are the most abundant fetally expressed proteins in the maternal bloodstream at term. This multigene family are immunoglobulin superfamily members and are predominantly expressed in the syncytiotrophoblast of human placenta and in giant cells and spongiotrophoblast of rodent placenta. PSGs are encoded by seventeen genes in the mouse and ten genes in the human. Little is known about the function of this gene family, although they have been implicated in immune modulation and angiogenesis through the induction of cytokines such as IL-10 and TGFβ1 in monocytes, and more recently, have been shown to inhibit the platelet-fibrinogen interaction. I provide new information concerning the evolution of the murine Psg genomic locus structure and organisation, through the discovery of a recent gene inversion event of Psg22 within the major murine Psg cluster. In addition to this, I have performed an examination of the expression patterns of individual Psg genes in placental and non-placental tissues. This study centres on Psg22, which is the most abundant murine Psg transcript detected in the first half of pregnancy. A novel alternative splice variant transcript of Psg22 lacking the protein N1-domain was discovered, and similar to the full length isoform induces TGFβ1 in macrophage and monocytic cell lines. The identification of a bidirectional antisense long non-coding RNA transcript directly adjacent to Psg22 and its associated active local chromatin conformation, suggests an interesting epigenetic gene-specific regulatory mechanism that may be responsible for the high level of Psg22 expression relative to the other Psg family members upon trophoblast giant cell differentiation

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Vitamin D deficiency during pregnancy, lactation, and early infancy has been widely reported. Current understanding of vitamin D metabolism during pregnancy and lactation is incomplete, and to date, experimental data to support vitamin D requirements for these life stages are scarce. There is a shortage of nationally representative data and appropriate reference ranges for serum 25-hydroxyvitamin D (25OHD) during pregnancy, lactation and infancy, including in umbilical cord blood. This thesis described concentrations of total 25OHD and individual metabolites including 25OHD3, 25OHD2, and 3-epi-25OHD3 at 15 weeks’ gestation in a large seasonally balanced pregnancy cohort study (n 1768), carried out in Cork, Ireland (52oN). The prevalence of low 25OHD concentrations in pregnant women was higher than published reports in other Caucasian women, and was highest among non-users of vitamin D-containing supplements during winter. A longitudinal pregnancy study was included which suggested gestational stages had an impact on the total serum 25OHD concentration. This thesis incorporated a randomized controlled trial carried out among 100 women across 3 intervention groups using 20 μg/day of vitamin D3 with or without 500 mg calcium, or placebo, over 12-weeks of lactation to investigate the vitamin D requirement for lactating mothers and the vitamin D content of human milk. A daily intake of 25 μg/day was suggested to meet the requirement of lactating women to maintain a 25OHD levels above 50 nmol/L in 97.5% of the population at 52oN all year around. However, vitamin D content in human milk did not increase in response to supplementation. Serum 25OHD concentration has been used as a predictor of a number of health outcomes. This thesis reported large differences in serum 25OHD concentrations using different methods in 86 umbilical cord samples. The need for international standardization of serum 25OHD measurements was re-emphasized in this thesis.

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The standard early markers for identifying and grading HIE severity, are not sufficient to ensure all children who would benefit from treatment are identified in a timely fashion. The aim of this thesis was to explore potential early biomarkers of HIE. Methods: To achieve this a cohort of infants with perinatal depression was prospectively recruited. All infants had cord blood samples drawn and biobanked, and were assessed with standardised neurological examination, and early continuous multi-channel EEG. Cord samples from a control cohort of healthy infants were used for comparison. Biomarkers studied included; multiple inflammatory proteins using multiplex assay; the metabolomics profile using LC/MS; and the miRNA profile using microarray. Results: Eighty five infants with perinatal depression were recruited. Analysis of inflammatory proteins consisted of exploratory analysis of 37 analytes conducted in a sub-population, followed by validation of all significantly altered analytes in the remaining population. IL-6 and IL-6 differed significantly in infants with a moderate/severely abnormal vs. a normal-mildly abnormal EEG in both cohorts (Exploratory: p=0.016, p=0.005: Validation: p=0.024, p=0.039; respectively). Metabolomic analysis demonstrated a perturbation in 29 metabolites. A Cross- validated Partial Least Square Discriminant Analysis model was developed, which accurately predicted HIE with an AUC of 0.92 (95% CI: 0.84-0.97). Analysis of the miRNA profile found 70 miRNA significantly altered between moderate/severely encephalopathic infants and controls. miRNA target prediction databases identified potential targets for the altered miRNA in pathways involved in cellular metabolism, cell cycle and apoptosis, cell signaling, and the inflammatory cascade. Conclusion: This thesis has demonstrated that the recruitment of a large cohortof asphyxiated infants, with cord blood carefully biobanked, and detailed early neurophysiological and clinical assessment recorded, is feasible. Additionally the results described, provide potential alternate and novel blood based biomarkers for the identification and assessment of HIE.

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Pregnancy-specific glycoproteins (PSGs) are highly glycosylated secreted proteins encoded by multi-gene families in some placental mammals. They are carcinoembryonic antigen (CEA) family and immunoglobulin (Ig) superfamily members. PSGs are immunomodulatory, and have been demonstrated to possess antiplatelet and pro-angiogenic properties. Low serum levels of these proteins have been correlated with adverse pregnancy outcomes. Objectives: Main research goals of this thesis were: 1). To attempt to replicate previously reported cytokine responses to PSG-treatment of immune cells and subsequently to investigate functionally important amino acids within PSG1. 2). To determine whether candidate receptor, integrin αvβ3, was a binding partner for PSG1 and to investigate whether PSG1 possessed functionality in a leukocyte-endothelial interaction assay. 3). To determine whether proteins generated from recently identified putative PSG genes in the horse shared functional properties with PSGs from other species. Outcomes: 1). Sequential domain deletion of PSG1 as well as mutation of conserved residues within the PSG1 Ndomain did not affect PSG1-induced TGF-β1. The investigated response was subsequently found to be the result of latent TGF-β1 contaminating the recombinant protein. Protein further purified by SEC to remove this showed no induction of TGF-β1. The most N-terminal glycosylation site was demonstrated to have an important role in PSG N domain secretion. PSG1 attenuated LPS-induced IL-6 and TNF-α. Investigations into signalling underpinning this proved inconclusive. 2). Integrin αvβ3 was identified as a novel PSG1 receptor mediating an as yet unknown function. Preliminary investigations into a role for PSGs as inhibitors of leukocyte endothelial interactions showed no effect by PSG1. 3). Horse PSG protein, CEACAM49, was shown to be similarly contaminated by latent TGF-β1 particle and once removed did not demonstrate TGF-β1 release. Interestingly horse PSG did show anti-platelet properties through inhibition of the plateletfibrinogen interaction as previously published for mouse and human PSGs.

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Background and Aims: Caesarean section rates have increased in recent decades and the effects on subsequent pregnancy outcome are largely unknown. Prior research has hypothesised that Caesarean section delivery may lead to an increased risk of subsequent stillbirth, miscarriage, ectopic pregnancy and sub-fertility. Structure and Methods: Papers 1-3 are systematic reviews with meta-analyses. Papers 4-6 are findings from this thesis on the rate of subsequent stillbirth, miscarriage, ectopic pregnancy and live birth by mode of delivery. Results Systematic reviews and meta-analyses: A 23% increased odds of subsequent stillbirth; no increase in odds of subsequent ectopic pregnancy and a 10% reduction in the odds of subsequent live birth among women with a previous Caesarean section were found in the various meta-analyses. Danish cohorts: Results from the Danish Civil Registration System (CRS) cohort revealed a small increased rate of subsequent stillbirth and ectopic pregnancy among women with a primary Caesarean section, which remained in the analyses by type of Caesarean. No increased rate of miscarriage was found among women with a primary Caesarean section. In the CRS data, women with a primary Caesarean section had a significantly reduced rate of subsequent live birth particularly among women with primary elective and maternal-requested Caesarean sections. In the Aarhus Birth Cohort, overall the effect of mode of delivery on the rate and time to next live birth was minimal. Conclusions: Primary Caesarean section was associated with a small increased rate of stillbirth and ectopic pregnancy, which may be in part due to underlying medical conditions. No increased rate of miscarriage was found. A reduced rate of subsequent live birth was found among Caesarean section in the CRS data. In the smaller ABC cohort, a small reduction in rate of subsequent live birth was found among women with a primary Caesarean section and is most likely due to maternal choice rather than any ill effects of the Caesarean. The findings of this study, the largest and most comprehensive to date will be of significant interest to health care providers and women globally.

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Background: Elective repeat caesarean delivery (ERCD) rates have been increasing worldwide, thus prompting obstetric discourse on the risks and benefits for the mother and infant. Yet, these increasing rates also have major economic implications for the health care system. Given the dearth of information on the cost-effectiveness related to mode of delivery, the aim of this paper was to perform an economic evaluation on the costs and short-term maternal health consequences associated with a trial of labour after one previous caesarean delivery compared with ERCD for low risk women in Ireland.Methods: Using a decision analytic model, a cost-effectiveness analysis (CEA) was performed where the measure of health gain was quality-adjusted life years (QALYs) over a six-week time horizon. A review of international literature was conducted to derive representative estimates of adverse maternal health outcomes following a trial of labour after caesarean (TOLAC) and ERCD. Delivery/procedure costs derived from primary data collection and combined both "bottom-up" and "top-down" costing estimations.Results: Maternal morbidities emerged in twice as many cases in the TOLAC group than the ERCD group. However, a TOLAC was found to be the most-effective method of delivery because it was substantially less expensive than ERCD ((sic)1,835.06 versus (sic)4,039.87 per women, respectively), and QALYs were modestly higher (0.84 versus 0.70). Our findings were supported by probabilistic sensitivity analysis.Conclusions: Clinicians need to be well informed of the benefits and risks of TOLAC among low risk women. Ideally, clinician-patient discourse would address differences in length of hospital stay and postpartum recovery time. While it is premature advocate a policy of TOLAC across maternity units, the results of the study prompt further analysis and repeat iterations, encouraging future studies to synthesis previous research and new and relevant evidence under a single comprehensive decision model.

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Background: Many European countries including Ireland lack high quality, on-going, population based estimates of maternal behaviours and experiences during pregnancy. PRAMS is a CDC surveillance program which was established in the United States in 1987 to generate high quality, population based data to reduce infant mortality rates and improve maternal and infant health. PRAMS is the only on-going population based surveillance system of maternal behaviours and experiences that occur before, during and after pregnancy worldwide.Methods: The objective of this study was to adapt, test and evaluate a modified CDC PRAMS methodology in Ireland. The birth certificate file which is the standard approach to sampling for PRAMS in the United States was not available for the PRAMS Ireland study. Consequently, delivery record books for the period between 3 and 5 months before the study start date at a large urban obstetric hospital [8,900 births per year] were used to randomly sample 124 women. Name, address, maternal age, infant sex, gestational age at delivery, delivery method, APGAR score and birth weight were manually extracted from records. Stillbirths and early neonatal deaths were excluded using APGAR scores and hospital records. Women were sent a letter of invitation to participate including option to opt out, followed by a modified PRAMS survey, a reminder letter and a final survey.Results: The response rate for the pilot was 67%. Two per cent of women refused the survey, 7% opted out of the study and 24% did not respond. Survey items were at least 88% complete for all 82 respondents. Prevalence estimates of socially undesirable behaviours such as alcohol consumption during pregnancy were high [>50%] and comparable with international estimates.Conclusion: PRAMS is a feasible and valid method of collecting information on maternal experiences and behaviours during pregnancy in Ireland. PRAMS may offer a potential solution to data deficits in maternal health behaviour indicators in Ireland with further work. This study is important to researchers in Europe and elsewhere who may be interested in new ways of tailoring an established CDC methodology to their unique settings to resolve data deficits in maternal health.

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Background: On-going surveillance of behaviours during pregnancy is an important but overlooked population health activity that is particularly lacking in Ireland. Few, if any, nationally representative estimates of most maternal behaviours and experiences are available. While on-going surveillance of maternal behaviours has not been a priority thus far in European countries including Ireland, on-going surveillance was identified as a key priority in the United States (US) during the 1980’s when the Pregnancy Risk Assessment Monitoring System (PRAMS), was established. Today, PRAMS is the only surveillance programme of maternal behaviours and experiences world-wide. Although on-going prevalence estimates are required in Ireland, studies which examine the offspring health effects of maternal behaviours are also required, since various questions regarding maternal exposures and their offspring health effects remain unanswered. Gestational alcohol consumption is one such important maternal exposure which is common in pregnancy, though its offspring health effects are unclear, particularly at lower or moderate levels. Thus, guidelines internationally have not reached consensus on safe alcohol recommendations for pregnant women. The aims of this thesis are to implement the PRAMS in Ireland (PRAMS Ireland), to describe the prevalence of health behaviours around the time of pregnancy in Ireland and to examine the effect of health behaviours on pregnancy and child outcomes (specifically the relationship between alcohol use during pregnancy and infant and child growth). Structure: In Chapter 1, a brief background and rationale for the work, as well as the thesis aims and objective is provided. A detailed description of the design and implementation of PRAMS Ireland is described in Chapter 2. Chapter 3 and Chapter 4 describe the methodological results of the implementation of the PRAMS Ireland pilot study and PRAMS Ireland main study. In Chapter 5, a comparison of alcohol prevalence in two Irish studies (PRAMS Ireland and Growing up in Ireland (GUI)) and one multi-centre prospective cohort study, Screening for Pregnancy Endpoints (SCOPE) Study is detailed. Chapter 6 describes findings on adherence to National Clinical Guidelines on health behaviours and nutrition around the time of pregnancy in PRAMS Ireland. Findings on exposure to alcohol use in pregnancy and infant growth outcomes are described in Chapter 7 and Chapter 8. The results of analysis conducted to examine the impact of gestational alcohol use on offspring growth trajectories to age ten are described in Chapter 9. Finally, a discussion of the findings, strengths and limitations of the thesis, direction for future research, policy, practice and public health implications are discussed in Chapter 10.Results: Implementation of PRAMS: PRAMS may be an effective system for the surveillance of health behaviours around the time of pregnancy in the Irish context. PRAMS Ireland had high response rates (67% and 61% response rates in the pilot and main study respectively), high item completion rates and valid prevalence estimates for many health behaviours. Examining prevalence of health behaviours: We found high levels of alcohol consumption before and during pregnancy, poor adherence to healthy diets and high levels of smoking before and during pregnancy among women in Ireland. Socially disadvantaged women had higher rates of deleterious health behaviours before pregnancy, although women with the most deleterious behaviour profiles before pregnancy appeared to experience the greatest gain in protective health behaviours during pregnancy. The impact of alcohol use on infant and offspring growth: We found that low and moderate levels of alcohol use did not impact on birth outcomes or offspring growth whereas heavy alcohol consumption resulted in reduced birth length and birth weight; however, this finding was not consistently observed across all studies. Selection, reporting and confounding biases which are common in observational research could be masking harmful effects. Conclusion: PRAMS is a valid and feasible method of surveillance of health behaviours around the time of pregnancy in Ireland. A surveillance program of maternal behaviours and experiences is immediately warranted due to high levels of deleterious health behaviours around the time of pregnancy in Ireland. Although our results do not indicate any evidence of harm, given the quality of evidence available, abstinence and advice of abstinence from alcohol may be the most prudent choice for patients and healthcare professionals respectively. Further studies of the effects of gestational alcohol use are required; particularly those which can reduce selection bias, reporting bias and confounding.

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Background: The first childbirth has the greatest impact on a woman’s pelvic floor when major changes occur. The aim of this study was to comprehensively describe pelvic floor dysfunction (PFD) in young nulliparous women, and its correlation with postnatal pathology. Methods: A prospective study was performed at Cork University Maternity Hospital, Ireland. Initially 1484 nulliparous women completed the validated Australian Pelvic Floor Questionnaire at 15 weeks’ gestation and repeatedly at one year postnatally (N=872). In the second phase, at least one year postnatally, 202 participants without subsequent pregnancies attended the clinical follow up which included: pelvic organ prolapse quantification, a 3D-Transperineal ultrasound scan and collagen level assessment. Results: A high pre-pregnancy prevalence of various types of PFD was detected, which in the majority of cases persisted postnatally and included multiple types of PFD. The first birth had a negative impact on severity of pre-pregnancy symptoms in <15% of cases. Apart from prolapse, vaginal delivery, including instrumental delivery did not increase the risk of PFD symptoms, where as Caesarean section was protective for all types of PFD. The first birth had a bigger impact on pre-existing symptoms of overactive bladder compared to stress urinary incontinence. Pelvic organ prolapse is extremely prevalent in young primiparous women, however usually it is low grade and asymptomatic. Congenital factors and high collagen type III levels play an important role in the aetiology of pelvic organs prolapse. Levator ani trauma is present in one in three women after the first pregnancy and delivery. Conclusion: The main damage to the pelvic floor most likely occurs due to an undiagnosed congenital intrinsic weakness of the pelvic floor structures. PFD is highly associated with first childbirth, however it seems that pregnancy and delivery are contributing factors only which unmask the congenital intrinsic weakness of the pelvic floor support.