950 research outputs found

    Circadian regulation of reproduction: From gamete to offspring

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    P01326625; Grants: GNT0519315Few challenges are more critical to the survival of a species than reproduction. To ensure reproductive success, myriad aspects of physiology and behaviour need to be tightly orchestrated within the animal, as well as timed appropriately with the external environment. This is accomplished through an endogenous circadian timing system generated at the cellular level through a series of interlocked transcription/translation feedback loops, leading to the overt expression of circadian rhythms. These expression patterns are found throughout the body, and are intimately interwoven with both the timing and function of the reproductive process. In this review we highlight the many aspects of reproductive physiology in which circadian rhythms are known to play a role, including regulation of the estrus cycle, the LH surge and ovulation, the production and maturation of sperm and the timing of insemination and fertilisation. We will also describe roles for circadian rhythms in support of the preimplantation embryo in the oviduct, implantation/placentation, as well as the control of parturition and early postnatal life. There are several key differences in physiology between humans and the model systems used for the study of circadian disruption, and these challenges to interpretation will be discussed as part of this review.M.J. Boden, T.J. Varcoe, D.J. Kennawa

    Opioid stimulation in the ventral tegmental area facilitates the onset of maternal behavior in rats

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    This research investigated the effect of an increase or decrease in opioid activity in the ventral tegmental area (VTA) on the onset of maternal behavior in rats. In Experiment 1, the latency to show maternal behavior toward foster rat pups (sensitization latency) was determined in maternally naive female rats given either nothing or a unilateral intra-VTA injection of morphine sulfate (MS) (0.0, 0.01, 0.03, 0.1 or 0.3 µg), on the first three days of a 10-day period of constant exposure to pups. Rats treated with 0.03 µg MS had significantly shorter sensitization latencies than did rats treated with 0.0 µg MS, 0.01 µg MS, or receiving no treatment (higher doses of morphine produced intermediate results). The facilitating effect of intra-VTA MS on the onset of maternal behavior was blocked by pretreatment with naltrexone hydrochloride and was found to have a specific site of action in the VTA (MS injections dorsal to the VTA were ineffective). In Experiment 2, sensitization latencies were determined in periparturitional rats given a bilateral intra-VTA injection of either the opioid antagonist naltrexone methobromide (quaternary naltrexone), its vehicle, a sham injection, or left untreated 40 min after delivery of the last pup. The mothers' own pups were removed at delivery; mothers were nonmaternal at the time of testing. Quaternary naltrexone treatment produced significantly slower sensitization to foster pups than did control conditions. Total activity and pup-directed activity did not differ significantly with treatment. The results demonstrate that increased opioid activity in the VTA facilitates the onset of maternal behavior in inexperienced nonpregnant female rats, and decreased opioid activity in the VTA disrupts the rapid onset of maternal behavior at parturition

    The Secretion of Areolar (Montgomery's) Glands from Lactating Women Elicits Selective, Unconditional Responses in Neonates

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    BACKGROUND:The communicative meaning of human areolae for newborn infants was examined here in directly exposing 3-day old neonates to the secretion from the areolar glands of Montgomery donated by non related, non familiar lactating women. METHODOLOGY/PRINCIPAL FINDINGS:The effect of the areolar stimulus on the infants' behavior and autonomic nervous system was compared to that of seven reference stimuli originating either from human or non human mammalian sources, or from an arbitrarily-chosen artificial odorant. The odor of the native areolar secretion intensified more than all other stimuli the infants' inspiratory activity and appetitive oral responses. These responses appeared to develop independently from direct experience with the breast or milk. CONCLUSION/SIGNIFICANCE:Areolar secretions from lactating women are especially salient to human newborns. Volatile compounds carried in these substrates are thus in a position to play a key role in establishing behavioral and physiological processes pertaining to milk transfer and production, and, hence, to survival and to the early engagement of attachment and bonding

    Electrohysterogram signal component cataloging with spectral and time-frequency methods

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    The Electrohysterogram (EHG) is a new instrument for pregnancy monitoring. It measures the uterine muscle electrical signal, which is closely related with uterine contractions. The EHG is described as a viable alternative and a more precise instrument than the currently most widely used method for the description of uterine contractions: the external tocogram. The EHG has also been indicated as a promising tool in the assessment of preterm delivery risk. This work intends to contribute towards the EHG characterization through the inventory of its components which are: • Contractions; • Labor contractions; • Alvarez waves; • Fetal movements; • Long Duration Low Frequency Waves; The instruments used for cataloging were: Spectral Analysis, parametric and non-parametric, energy estimators, time-frequency methods and the tocogram annotated by expert physicians. The EHG and respective tocograms were obtained from the Icelandic 16-electrode Electrohysterogram Database. 288 components were classified. There is not a component database of this type available for consultation. The spectral analysis module and power estimation was added to Uterine Explorer, an EHG analysis software developed in FCT-UNL. The importance of this component database is related to the need to improve the understanding of the EHG which is a relatively complex signal, as well as contributing towards the detection of preterm birth. Preterm birth accounts for 10% of all births and is one of the most relevant obstetric conditions. Despite the technological and scientific advances in perinatal medicine, in developed countries, prematurity is the major cause of neonatal death. Although various risk factors such as previous preterm births, infection, uterine malformations, multiple gestation and short uterine cervix in second trimester, have been associated with this condition, its etiology remains unknown [1][2][3]

    Maternal Programming: Application of a Developmental Psychopathology Perspective

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    The fetal phase of life has long been recognized as a sensitive period of development. Here we posit that pregnancy represents a simultaneous sensitive period for the adult female with broad and persisting consequences for her health and development, including risk for psychopathology. In this review, we examine the transition to motherhood through the lens of developmental psychopathology. Specifically, we summarize the typical and atypical changes in brain and behavior that characterize the perinatal period. We highlight how the exceptional neuroplasticity exhibited by women during this life phase may account for increased vulnerability for psychopathology. Further, we discuss several modes of signaling that are available to the fetus to affect maternal phenotypes (hormones, motor activity, and gene transfer) and also illustrate how evolutionary perspectives can help explain how and why fetal functions may contribute to maternal psychopathology. The developmental psychopathology perspective has spurred advances in understanding risk and resilience for mental health in many domains. As such, it is surprising that this major epoch in the female life span has yet to benefit fully from similar applications

    Improving pregnancy outcomes in humans through studies in sheep

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    Experimental studies that are relevant to human pregnancy rely on the selection of appropriate animal models as an important element in experimental design. Consideration of the strengths and weaknesses of any animal model of human disease is fundamental to effective and meaningful translation of preclinical research. Studies in sheep have made significant contributions to our understanding of the normal and abnormal development of the fetus. As a model of human pregnancy, studies in sheep have enabled scientists and clinicians to answer questions about the etiology and treatment of poor maternal, placental, and fetal health and to provide an evidence base for translation of interventions to the clinic. The aim of this review is to highlight the advances in perinatal human medicine that have been achieved following translation of research using the pregnant sheep and fetus

    Bovine parturition: welfare and production implications of assistance and ketoprofen analgesia

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    Parturition is a necessary event for productive dairy cows (and their calves) and assisted parturition is common. Although difficult parturition is believed by farmers and veterinary surgeons to be painful and stressful for cows and their calves, data to support this view are limited. Previous studies typically analysed the effects of assistance or analgesia as individual effects but inclusion of both in a factorial design is rare, so the association between pain and parturition assistance is not certain. Furthermore, there is a paucity of studies investigating calf birth-related experiences in general, and available work typically focuses on health and productivity rather than more sensitive measures of welfare (e.g. behaviour). Differences in study design further challenge the interpretation and practical application of available data; most studies refer to ‘dystocia’, but definitions of this term vary widely and important differences between veterinary and farmer provided assistance are not always acknowledged. Accordingly, it is currently difficult to develop evidence based recommendations for farmers and veterinary surgeons regarding the value of analgesic provision to cows and calves around parturition. Farmers are recommended to closely monitor cows that may need assisted parturition to enable intervention to be optimised; however, this can be difficult to achieve particularly if staff availability is limited, and it is currently not possible to accurately predict when cows will give birth, or whether they are likely to need assistance. As such, some cows that experience difficult parturition may not receive timely assistance and conversely, some cows may be assisted unnecessarily — both are situations that may challenge welfare. The studies presented in this thesis aimed to investigate the effects of farmer-assisted parturition and administration of the non-steroidal anti-inflammatory drug ketoprofen on the welfare, health, and productivity of commercially managed Holstein dairy cows and calves (Bos taurus) using a 2 x 2 factorial study design. Further work aimed to support the findings of initial studies using accelerometer generated data to analyse behavioural patterns of cows and calves for up to 48 h postpartum. A final aim was to assess the potential for data generated by animal-worn accelerometers to detect cows that are likely to need farmer-provided assistance at parturition. Cows and calves subject to farmer-assisted and unassisted parturition were randomly assigned to receive either ketoprofen or saline within 3 h of parturition. Behaviour in the first 48 h postpartum was analysed using focal instantaneous sampling (visual observations) to investigate welfare outcomes. Detailed behavioural analysis was complemented with analysis of biomarkers indicative of health and welfare status (cortisol, creatine kinase [cows and calves]; L-lactate, plasma total protein [calves only]) in the first 7 d postpartum. Regardless of ketoprofen treatment, cows and calves subject to assisted birth showed behavioural differences consistent with a reduced welfare state (increased lateral recumbency [both] and reduced play [calves only]), compared to unassisted animals. Additionally, the plasma cortisol concentration of assisted cows was higher than unassisted cows immediately after parturition, suggesting assisted parturition is associated with heightened maternal stress. Irrespective of assistance status, cows and calves treated with ketoprofen engaged in behaviours consistent with pain and reduced welfare less than saline treated animals. Additionally, ketoprofen treated cows engaged in lying postures suggestive of improved comfort, and ketoprofen treated calves engaged in play behaviour more than saline treated cows and calves respectively (regardless of assistance status) — suggesting that all cows and calves experience pain after parturition that can be improved by ketoprofen. Results of further work using accelerometers to continuously monitor behaviour for 48 h after parturition corroborated these findings — ketoprofen treated cows and calves were more active than saline treated animals and ketoprofen treated calves engaged in increased play behaviour. Health and productivity data for cows and calves recruited in initial work were obtained from farm records: cow data were collected until the end of the subsequent lactation (approximately one year), calf data were collected until the end of the first lactation (approximately three years). Regardless of treatment status, parturition assistance was associated with increased postpartum disease and reduced maternal reproductive performance in the subsequent lactation. Birth assistance was associated with poorer growth of calves before first parturition and reduced reproductive performance in the first lactation (irrespective of treatment status). Ketoprofen treated cows had a 305 d mature equivalent milk yield 664 kg higher than saline treated cows, irrespective of assistance status. Ketoprofen treatment did not affect measures of calf productivity overall but ketoprofen treated assisted calves had a growth rate to weaning 0.1 kg/d higher than calves in the other assistance x treatment status interaction groups. Accelerometer generated data (primarily step count) showed potential for detection of cows more likely to need assistance, although a threshold for detection could not be established with high accuracy. Additionally, the number of lying bouts exhibited by cows in the last 12 h of gestation showed promise for predicting the timing of parturition. These data suggest that leg-worn accelerometers may be a valuable tool to aid pre-partum management of dairy cows, and the results presented here offer a starting point for the development of pre-partum specific algorithms for use in future remote devices. Collectively, the results presented in these studies indicate that parturition assistance is negatively associated with welfare and future productivity of cows and calves, and that ketoprofen administration immediately after parturition has beneficial effects on these outcomes. However, observed interaction effects were few, suggesting that a) farmer-assisted cows and calves experience challenges to welfare that extend beyond pain (i.e. challenges that cannot be manipulated using analgesia), and b) pain is experienced by all cows and calves after parturition, not just those that are assisted. These findings suggest that assistance at parturition should be provided judiciously and not be a routine management intervention. Furthermore, these results provide a robust basis on which inclusion of ketoprofen administration in parturition and newborn calf management protocols can be recommended to dairy farmers and veterinary surgeons seeking to optimise the welfare and productivity of Holstein cows and calves managed in a housed dairy system
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