Publications by authors named "Tamara J Varcoe"

Background: Psychological distress is prevalent amongst hospital in-patient and may predispose patients to potentially preventable readmissions after discharge. A particularly vulnerable group are patients with cardiac disorders. This study tested the feasibility of a brief cognitive behavioural therapy consisting of an in-hospital coping session and a post-discharge healthy sleep session.

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Introduction: Non-alcoholic fatty liver disease (NAFLD) is characterised by accumulation of triglycerides and cholesterol within the liver and dysregulation of specific hepatic cytochrome P450 (CYPs) activity. CYPs are involved in the metabolism of endogenous and exogenous chemicals. Hepatic CYP activity is dysregulated in human studies and animal models of a Western diet (WD) or low birth weight (LBW) independently, but the additive effects of LBW and postnatal WD consumption are unknown.

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Purpose: Ten percent of pregnancies are affected by intrauterine growth restriction (IUGR), and evidence suggests that affected neonates have reduced activity of hepatic cytochrome P450 (CYP) drug metabolising enzymes. Given that almost all pregnant individuals take medications and additional medications are often required during an IUGR pregnancy, we aimed to determine the impact of IUGR on hepatic CYP activity in sheep fetuses and pregnant ewes.

Methods: Specific probes were used to determine the impact of IUGR on the activity of several CYP isoenzymes (CYP1A2, CYP2C19, CYP2D6 and CYP3A) in sheep fetuses and pregnant ewes.

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Key Points: Chronic hypoxaemia is associated with intrauterine growth restriction (IUGR) and a predisposition to the development of hypertension in adult life. IUGR fetuses exhibit a greater reliance on α-adrenergic activation for blood pressure regulation. The fetal blood pressure response to post-ganglionic blockade is not different between control and IUGR fetuses.

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Key Points: Maternal shift work increases the risk of pregnancy complications, although its effects on progeny health after birth are not clear. We evaluated the impact of a simulated shift work protocol for one-third, two-thirds or all of pregnancy on the metabolic health of sheep progeny. Simulated shift work had no effect on growth, body size, body composition or glucose tolerance in pre-pubertal or young adult progeny.

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With the increased prevalence of non-communicable disease and availability of medications to treat these and other conditions, a pregnancy free from prescribed medication exposure is rare. Up to 99% of women take at least one medication during pregnancy. These medications can be divided into those used to improve maternal health and wellbeing (e.

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At birth, weight of the neonate is used as a marker of the 9-month journey as a fetus. Those neonates born less than the 10th centile for their gestational age are at risk of being intrauterine growth restricted. However, this depends on their genetic potential for growth and the intrauterine environment in which they grew.

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Preclinical imaging studies of fetal hemodynamics require anesthesia to immobilize the animal. This may induce cardiovascular depression and confound measures under investigation. We compared the impact of four anesthetic regimes upon maternal and fetal blood gas and hemodynamics during baseline periods of normoxia, and in response to an acute hypoxic challenge in pregnant sheep.

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Key Points: Shift work impairs metabolic health, although its effects during pregnancy are not well understood We evaluated the effects of a simulated shift work protocol for one-third, two-thirds or all of pregnancy on maternal and pregnancy outcomes in sheep. Simulated shift work changed the timing of activity, disrupted hormonal and cellular rhythms, and impaired maternal glucose tolerance during early pregnancy. Gestation length was increased in twin pregnancies, whereas singleton lambs were lighter at a given gestational age if mothers were subjected to shift work conditions in the first one-third of pregnancy.

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Polycystic ovary syndrome (PCOS) is a complex endocrine disorder affecting the reproductive, metabolic and psychological health of women. Clinic-based studies indicate that sleep disturbances and disorders including obstructive sleep apnea and excessive daytime sleepiness occur more frequently among women with PCOS compared to comparison groups without the syndrome. Evidence from the few available population-based studies is supportive.

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The in utero environment is inherently rhythmic, with the fetus subjected to circadian changes in temperature, substrates, and various maternal hormones. Meanwhile, the fetus is developing an endogenous circadian timing system, preparing for life in an external environment where light, food availability, and other environmental factors change predictably and repeatedly every 24 h. In humans, there are many situations that can disrupt circadian rhythms, including shift work, international travel, insomnias, and circadian rhythm disorders (e.

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Animal studies demonstrate that circadian rhythm disruption during pregnancy can be deleterious to reproductive capacity and the long-term health of the progeny. Our previous studies in rats have shown that exposure of pregnant dams to an environment that significantly disrupts maternal circadian rhythms programs increased adiposity and poor glucose metabolism in offspring. In this study, we used mice with a ClockΔ19 mutation to determine whether foetal development within a genetically disrupted circadian environment affects pregnancy outcomes and alters the metabolic health of offspring.

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This review summarizes the evidence concerning effects of night shift work on women's reproductive health, specifically difficulty in conceiving and miscarriage. We distinguish between fixed night shift and rotating night shift, as the population subgroups exposed, the social and biological mechanisms, and the magnitude of effects are likely to differ; of note, women working fixed night shift are known to have high tolerance for this schedule. We identified two relevant systematic reviews with meta-analyses and five additional studies.

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The Robinson Research Institute of the University of Adelaide convened a multidisciplinary group of n = 33 clinicians, researchers and representatives of government organisations on the 2 October 2014 for a workshop entitled "Promoting fertility and healthy conception. How do we generate greater reproductive health awareness?" The key aim of the workshop was to assess the body of knowledge that informs clinical practice and government policy, and to identify questions and additional information needed by health practitioners and government representatives working in the field of reproductive health and to frame future research and policy. The workshop identified topics that fell mostly into three categories: lifestyle-related, societal and biological factors.

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Disrupting circadian rhythms in rodents perturbs glucose metabolism and increases adiposity. To determine whether these effects occur in a large diurnal animal, we assessed the impact of circadian rhythm disruption upon metabolic function in sheep. Adult ewes (n = 7) underwent 3 weeks of a control 12 h light-12 h dark photoperiod, followed by 4 weeks of rapidly alternating photoperiods (RAPs) whereby the time of light exposure was reversed twice each week.

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The time of day at which meals are consumed is known to impact on behaviour as well as physiological systems. In this study we investigated the behavioural and physiological effects of restricting access to food to the light or dark period in mice maintained on either long or short photoperiods. In both photoperiods, wheel running commenced upon the onset of darkness and was generally confined to the period of darkness.

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The close relationship between circadian rhythm disruption and poor metabolic status is becoming increasingly evident, but role of adipokines is poorly understood. Here we investigated adipocyte function and the metabolic status of mice with a global loss of the core clock gene Bmal1 fed either a normal or a high fat diet (22% by weight). Bmal1 null mice aged 2 months were killed across 24 hours and plasma adiponectin and leptin, and adipose tissue expression of Adipoq, Lep, Retn and Nampt mRNA measured.

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Disrupting maternal circadian rhythms through exposure to chronic phase shifts of the photoperiod has lifelong consequences for the metabolic homeostasis of the fetus, such that offspring develop increased adiposity, hyperinsulinaemia and poor glucose and insulin tolerance. In an attempt to determine the mechanisms by which these poor metabolic outcomes arise, we investigated the impact of chronic phase shifts (CPS) on maternal and fetal hormonal, metabolic and circadian rhythms. We assessed weight gain and food consumption of dams exposed to either CPS or control lighting conditions throughout gestation.

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Circadian rhythms impact on a wide range of physiological systems and this impact extends to fertility, such that disruptions to timing systems can impact upon reproductive capacity. This is highlighted most obviously in mutant mouse models whereby deletion or mutation of single genes results not only in disrupted circadian rhythmicity, but also compromised male and female reproductive function. In this review, we discuss the presence of circadian clocks in female and male reproductive tissues and the role these clocks play in the generation of oestrus cycles, ovulation, sperm generation, implantation and the maintenance of pregnancy.

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Shift work during pregnancy is associated with an increased risk for preterm birth and low birth weight. However, the impact upon the long term health of the children is currently unknown. In this study, we used an animal model to determine the consequences of maternal shift work exposure on the health of the adult offspring.

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The light/dark cycle and suprachiasmatic nucleus rhythmicity are known to have important influences on reproductive function of rodents. We studied reproductive function in female heterozygous and homozygous brain and muscle ARNT-like protein 1 (Bmal1, also known as Arntl) null mice, which lack central and peripheral cellular rhythms. Heterozygous Bmal1 mice developed normally and were fertile, with apparent normal pregnancy progression and litter size, although postnatal mortality up to weaning was high (1.

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The suprachiasmatic nucleus of the hypothalamus receives dense serotonergic projections from the raphe nuclei. This input may be involved in the transmission of photic information with activation of 5-HT receptors at night having a photo-mimetic effect. 5-HT2C receptors have been implicated in this role, with 5-HT2C receptor agonist administration at night resulting in the induction of cFOS protein, and a phase delay of melatonin metabolite excretion rhythms in a manner similar to light.

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