Adult cortical plasticity depends on an early postnatal critical period

Development of the cerebral cortex is influenced by sensory experience during distinct phases of postnatal development known as critical periods. Disruption of experience during a critical period produces neurons that lack specificity for particular stimulus features, such as location in the somatosensory system. Synaptic plasticity is the agent by which sensory experience affects cortical development. Here, we describe, in mice, a developmental critical period that affects plasticity itself. Transient neonatal disruption of signaling via the C-terminal domain of "disrupted in schizophrenia 1" (DISC1)-a molecule implicated in psychiatric disorders-resulted in a lack of long-term potentiation (LTP) (persistent strengthening of synapses) and experience-dependent potentiation in adulthood. Long-term depression (LTD) (selective weakening of specific sets of synapses) and reversal of LTD were present, although impaired, in adolescence and absent in adulthood. These changes may form the basis for the cognitive deficits associated with mutations in DISC1 and the delayed onset of a range of psychiatric symptoms in late adolescence.

Impact of suspected food allergy on emotional distress and family life of parents prior to allergy diagnosis

Background: Food allergy is associated with psychological distress in both child and parent. It is unknown whether parental distress is present prior to clinical diagnosis or whether experiences at clinic can reduce any distress present. This study aimed to assess anxiety and depression in parents and the impact of suspected food allergy on the lives of families before and after a visit to an allergy clinic. Methods: One hundred and twenty-four parents visiting an allergy clinic for the first time to have their child assessed for food allergy completed a study-specific questionnaire and the Hospital Anxiety and Depression Scale; 50 parents completed these 4-6 wk later in their own home. Results: Most parents (86.4%) reported suspected food allergy had an impact on their family life prior to clinic attendance; 76% had made changes to their child's diet. 32.5% of parents had mild-to-severe anxiety before their clinic visit; 17.5% had mild-to-moderate depression. Post-clinic, 40% had mild-to-severe anxiety; 13.1% had mild-to-moderate depression. There were no significant differences in anxiety (p = 0.34) or depression scores (p = 0.09) before and after the clinic visit. Conclusions: Anxiety and depression is present in a small proportion of parents prior to diagnosis of food allergy in their child and this does not reduce in the short term after the clinic visit. Identification of parents at risk of suffering from distress is needed and ways in which we communicate allergy information before and at clinic should be investigated to see if we can reduce distress. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Can illness perceptions and coping predict psychological distress amongst allergy sufferers?

Objective. The aim of the present study was to measure the extent to which illness perceptions and coping strategies are associated with the levels of psychological distress amongst allergy sufferers. Design and method. One hundred and fifty-six allergy sufferers (all members of Allergy U.K.) completed a postal survey consisting of the Revised Illness Perception Questionnaire (IPQ-R) and the COPE. Psychological distress was measured using the General Health Questionnaire (GHQ-28) and the Perceived Stress Scale (PSS). Results. Multiple regression analyses indicated that illness perceptions explained between 6 and 26% of variance on measures of psychological distress; coping strategies explained between 12 and 25%. A strong illness identity and emotional representations of the allergy were associated with higher levels of psychological distress; as were less adaptive coping strategies such as focusing on and venting of emotions. Strong personal control beliefs were associated with the lower levels of distress, as were adaptive coping strategies such as positive reinterpretation and growth. Coping partially mediated the link between the illness perceptions and the outcome; however, illness identity, emotional representations and personal control retained an independent significant association with psychological distress. Conclusion. The findings support a role for illness perceptions and coping in explaining levels of psychological distress amongst allergy sufferers. This has implications for targeted health interventions aimed at reducing the strength of illness identity and emotional representations and increasing a sense of control and the use of more adaptive coping strategies.

Appetite regulatory mechanisms and food intake in mice are sensitive to mismatch in diets between pregnancy and postnatal periods

Human and animal studies suggest that obesity in adulthood may have its origins partly during prenatal development. One of the underlying causes of obesity is the perturbation of hypothalamic mechanisms controlling appetite. We determined mRNA levels of genes that regulate appetite, namely neuropeptide Y (NPY), pro-opiomelanocortin (POMC) and the leptin receptor isoform Ob-Rb, in the hypothalamus of adult mouse offspring from pregnant dams fed a protein-restricted diet, and examined whether mismatched post-weaning high-fat diet altered further expression of these gene transcripts. Pregnant MF1 mice were fed either normal protein (C, 18% casein) or protein-restricted (PR, 9% casein) diet throughout pregnancy. Weaned offspring were fed to adulthood a high-fat (HF; 45% kcal fat) or standard chow (21% kcal fat) diet to generate the C/HF, C/C, PR/HF and PR/C groups. Food intake and body weight were monitored during this period. Hypothalamic tissues were collected at 16 weeks of age for analysis of gene expression by real time RT-PCR. All HF-fed offspring were observed to be heavier vs. C groups regardless of the maternal diet during pregnancy. In the PR/HF males, but not in females, daily energy intake was reduced by 20% vs. the PR/C group (p <0.001). In PR/HF males, hypothalamic mRNA levels were lower vs. the PR/C group for NPY (p <0.001) and Ob-Rb (p <0.05). POMC levels were similar in all groups. In females, mRNA levels for these transcripts were similar in all groups. Our results suggest that adaptive changes during prenatal development in response to maternal dietary manipulation may have long-term sex-specific consequences on the regulation of appetite and metabolism following post-weaning exposure to an energy-rich nutritional environment. © 2008 Elsevier B.V. All rights reserved.

Mouse embryo culture induces changes in postnatal phenotype including raised systolic blood pressure

A key factor in the use of assisted reproductive technologies (ART) for diverse species is the safety of procedures for long-term health. By using a mouse model, we have investigated the effect of in vitro culture and embryo transfer (ET) of superovulated embryos on postnatal growth and physiological activity compared with that of embryos developing in vivo. Embryo culture from two-cell to blastocyst stages in T6 medium either with or without a protein source reduced blastocyst trophectoderm and inner cell mass cell number compared with that of embryos developing in vivo. Embryo culture and ET had minimal effects on postnatal growth when compared with in vivo development with an equivalent litter size. However, embryo culture, and to a lesser extent ET, led to an enhanced systolic blood pressure at 21 weeks compared with in vivo development independent of litter size, maternal origin, or body weight. Moreover, activity of enzymatic regulators of cardiovascular and metabolic physiology, namely, serum angiotensin-converting enzyme and the gluconeogenesis controller, hepatic phosphoeno/pyruvate carboxykinase, were significantly elevated in response to embryo culture and/or ET in female offspring at 27 weeks, independent of maternal factors and postnatal growth. These animal data indicate that postnatal physiological criteria important in cardiovascular and metabolic health may be more sensitive to routine ART procedures than growth. © 2007 by The National Academy of Sciences of the USA.

The influence of mouse Ped gene expression on postnatal development

The Ped (preimplantation embryo development) gene, whose product is Qa-2 protein, is correlated with a faster rate of preimplantation development (Ped fast phenotype) in mice that express Qa-2 protein compared with mice with an absence of Qa-2 protein (Ped slow phenotype). In the current study, we have used two congenic mouse strains differentially expressing the Ped gene, strain B6.K1 (Ped slow; Qa-2 negative) and strain B6.K2 (Ped fast; Qa-2 positive), to investigate the effects of Ped gene expression on postnatal growth profiles, systolic blood pressure and adult organ allometry. At birth, B6.K1 mice were moderately lighter than B6.K2 mice. B6.K1 mice became heavier during postnatal life (P

The role of illness perceptions:psychological distress and treatment seeking delay in patients with genital warts.

This study examined the relationships between illness perceptions, psychological distress and treatment-seeking delay in genital warts patients. Sixty-six genital warts patients were approached while attending a sexual health clinic. They completed a questionnaire assessing their illness perceptions, psychological distress and treatment-seeking delay. Negative perceptions of illness consequences and control and a perceived cyclical timeline were associated with increased psychological distress. Perceived illness consequences maintained significance in a multiple regression equation, which accounted for 25% variance in distress. Depression was associated with treatment-seeking delay (r = 0.28, P = 0.03). In conclusion, illness perceptions may play an important role in the experience of psychological distress in genital warts patients. The implications of these findings for the design of health-care interventions are discussed.

Distress risk, growth and earnings quality

We extend and complement prior work by investigating the earnings quality of firms with different financial health characteristics and growth prospects. By using three alternative measures of default likelihood and two alternative measures of growth options, without being limited to a specific event, we provide a more comprehensive setup for analysing the earnings characteristics of the universe of firms than examining distressed firms with persistent losses, dividend reductions or bankruptcy-filings. Our dataset consists of 15,049 healthy U.S. firms over the period 1990-2004. Results show that the relation between earnings quality and financial health is not monotonic. Distressed firms have a low level of earnings timeliness for bad news and a high level for good news, and manage earnings toward a positive target more frequently than healthy firms. On the other hand, healthy firms have a high level of earnings timeliness for bad news. Growth aspects play an important role in a firm's ability to manage earnings. In contrast to the findings of prior studies, growth firms have greater earnings timeliness for bad news, whereas value firms manage earnings toward a positive target more frequently than growth firms. © 2011 The Authors. Abacus© 2011 Accounting Foundation, The University of Sydney.

Tests of the Intersensory Redundancy Hypothesis across early postnatal development

The Intersensory Redundancy Hypothesis (IRH; Bahrick & Lickliter, 2000, 2002, 2012) predicts that early in development information presented to a single sense modality will selectively recruit attention to modality-specific properties of stimulation and facilitate learning of those properties at the expense of amodal properties (unimodal facilitation). Vaillant (2010) demonstrated that bobwhite quail chicks prenatally exposed to a maternal call alone (unimodal stimulation) are able to detect a pitch change, a modality-specific property, in subsequent postnatal testing between the familiarized call and the same call with altered pitch. In contrast, chicks prenatally exposed to a maternal call paired with a temporally synchronous light (redundant audiovisual stimulation) were unable to detect a pitch change. According to the IRH (Bahrick & Lickliter, 2012), as development proceeds and the individual's perceptual abilities increase, the individual should detect modality-specific properties in both nonredundant, unimodal and redundant, bimodal conditions. However, when the perceiver is presented with a difficult task, relative to their level of expertise, unimodal facilitation should become evident. The first experiment of the present study exposed bobwhite quail chicks 24 hr after hatching to unimodal auditory, nonredundant audiovisual, or redundant audiovisual presentations of a maternal call for 10min/hr for 24 hours. All chicks were subsequently tested 24 hr after the completion of the stimulation (72 hr following hatching) between the familiarized maternal call and the same call with altered pitch. Chicks from all experimental groups (unimodal, nonredundant audiovisual, and redundant audiovisual exposure) significantly preferred the familiarized call over the pitch-modified call. The second experiment exposed chicks to the same exposure conditions, but created a more difficult task by narrowing the pitch range between the two maternal calls with which they were tested. Chicks in the unimodal and nonredundant audiovisual conditions demonstrated detection of the pitch change, whereas the redundant audiovisual exposure group did not show detection of the pitch change, providing evidence of unimodal facilitation. These results are consistent with predictions of the IRH and provide further support for the effects of unimodal facilitation and the role of task difficulty across early development.

Elevated progesterone in yolk as a moderator of prenatal and postnatal auditory learning in bobwhite quail

Recent studies have established that yolk hormones of maternal origin have significant effects on the physiology and behavior of offspring in birds. Herrington (2012) demonstrated that an elevation of progesterone in yolk elevates emotional reactivity in bobwhite quail neonates. Chicks that hatched from progesterone treated eggs displayed increased latency in tonic immobility and did not emerge as quickly from a covered location into an open field compared to control groups. For the present study, three experimental groups were formed: chicks hatched from eggs with artificially elevated progesterone (P), chicks hatched from an oil-vehicle control group (V), and chicks hatched from a non-manipulated control group (C). Experiment 1 examined levels of progesterone with High Performance Liquid Chromatography/tandem Mass Spectroscopy (HPLC/MS) from prenatal day 1 to prenatal day 17 in bobwhite quail egg yolk. In Experiment 2, bobwhite quail embryos were passively exposed to an individual maternal assembly call for 24 hours prior to hatching. Chicks were then tested individually for their preference between the familiarized call and a novel call at 24 and 48 hours following hatching. For Experiment 3, newly hatched chicks were exposed to an individual maternal assembly call for 24-hrs. Chicks were then tested for their preference for the familiarized call at 24 and 48-hrs after hatch. Results of Experiment 1 showed that yolk progesterone levels were significantly elevated in treated eggs and were present in the egg yolk longer into prenatal development than the two control groups. Results from Experiment 2 indicated that chicks from the P group failed to demonstrate a preference for the familiar bobwhite maternal assembly call at 24 or 48-hrs after hatch following 24-hrs of prenatal exposure. In contrast, chicks from the C and V groups demonstrated a significant preference for the familiarized call. In Experiment 3, chicks from the P group showed an enhanced preference for the familiarized bobwhite maternal call compared to chicks from the C and V groups at 24 and 48-hrs after hatch. The results of these experiments suggest that elevated maternal yolk hormone levels in pre-incubated bobwhite quail eggs can influence auditory perceptual learning in embryos and neonates.^

Fast and efficient : Postnatal growth and energy expenditure in an Arctic-breeding waterbird, the Red-throated Loon (Gavia stellata)

Peer reviewed

Postnatal pelvic floor muscle training for preventing and treating urinary incontinence : where do we stand?

Purpose of review: Postnatal pelvic floor muscle training aims to rehabilitate the pelvic floor muscles. To be effective, a certain exercise dosage must be respected. Recent trials evaluated the effect of different programs on prevention/treatment of urinary incontinence immediately after delivery and in treatment of persistent incontinence. Recent findings: Only three systematic reviews, six trials, and four follow-up studies have been published in the past two decades. High heterogeneity in postnatal pelvic floor muscle training programs is observed throughout the literature, making comparisons difficult. In the prevention/treatment of postnatal urinary incontinence immediately after delivery and in persistent incontinence, supervised intensive programs prove more effective than standard postnatal care. Longer-term results have yet to show advantages for postnatal training programs. Summary: Although a certain exercise dosage must be respected for a postnatal pelvic floor muscle training program to be effective, a few randomized controlled trials present such dosage. Randomized controlled trials should study the effect of supervised, intensive training protocols with adherence aids. As standard care does not seem to reduce the prevalence of postnatal urinary incontinence, obstetrics services must address delivery of postnatal pelvic floor muscle training.

Effets d'un suivi postnatal intensif et précoce auprès de mères adolescentes sur le niveau de soutien perçu et la structure de leur réseau familial et communautaire

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Postnatal development of glutamatergic receptormediated excitatory postsynaptic currents and their modulations by ach and dopamine in nucleus accumbens

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.