NMDA Receptor C-Terminal Domain Signalling in Development, Maturity, and Disease

The NMDA receptor is a Ca²⁺-permeant glutamate receptor which plays key roles in health and disease. Canonical NMDARs contain two GluN2 subunits, of which 2A and 2B are predominant in the forebrain. Moreover, the relative contribution of 2A vs. 2B is controlled both developmentally and in an activity-dependent manner. The GluN2 subtype influences the biophysical properties of the receptor through difference in their N-terminal extracellular domain and transmembrane regions, but they also have large cytoplasmic Carboxyl (C)-terminal domains (CTDs) which have diverged substantially during evolution. While the CTD identity does not influence NMDAR subunit specific channel properties, it determines the nature of CTD-associated signalling molecules and has been implicated in mediating the control of subunit composition (2A vs. 2B) at the synapse. Historically, much of the research into the differential function of GluN2 CTDs has been conducted in vitro by over-expressing mutant subunits, but more recently, the generation of knock-in (KI) mouse models have allowed CTD function to be probed in vivo and in ex vivo systems without heterologous expression of GluN2 mutants. In some instances, findings involving KI mice have been in disagreement with models that were proposed based on earlier approaches. This review will examine the current research with the aim of addressing these controversies and how methodology may contribute to differences between studies. We will also discuss the outstanding questions regarding the role of GluN2 CTD sequences in regulating NMDAR subunit composition, as well as their relevance to neurodegenerative disease and neurodevelopmental disorders.

Intermittent bolus feeding does not enhance protein synthesis, myonuclear accretion, or lean growth more than continuous feeding in a premature piglet model

Optimizing enteral nutrition for premature infants may help mitigate extrauterine growth restriction and adverse chronic health outcomes. Previously, we showed in neonatal pigs born at term that lean growth is enhanced by intermittent bolus compared with continuous feeding. The objective was to determine if prematurity impacts how body composition, muscle protein synthesis, and myonuclear accretion respond to feeding modality. Following preterm delivery, pigs were fed equivalent amounts of formula delivered either as intermittent boluses (INT; n = 30) or continuously (CONT; n = 14) for 21 days. Body composition was measured by dual-energy X-ray absorptiometry (DXA) and muscle growth was assessed by morphometry, myonuclear accretion, and satellite cell abundance. Tissue anabolic signaling and fractional protein synthesis rates were determined in INT pigs in postabsorptive (INT-PA) and postprandial (INT-PP) states and in CONT pigs. Body weight gain and composition did not differ between INT and CONT pigs. Longissimus dorsi (LD) protein synthesis was 34% greater in INT-PP than INT-PA pigs (P < 0.05) but was not different between INT-PP and CONT pigs. Phosphorylation of 4EBP1 and S6K1 and eIF4E·eIF4G abundance in LD paralleled changes in LD protein synthesis. Satellite cell abundance, myonuclear accretion, and fiber cross-sectional area in LD did not differ between groups. These results suggest that, unlike pigs born at term, intermittent bolus feeding does not enhance lean growth more than continuous feeding in pigs born preterm. Premature birth attenuates the capacity of skeletal muscle to respond to cyclical surges in insulin and amino acids with intermittent feeding in early postnatal life.NEW & NOTEWORTHY Extrauterine growth restriction often occurs in premature infants but may be mitigated by optimizing enteral feeding strategies. We show that intermittent bolus feeding does not increase skeletal muscle protein synthesis, myonuclear accretion, or lean growth more than continuous feeding in preterm pigs. This attenuated anabolic response of muscle to intermittent bolus feeding, compared with previous observations in pigs born at term, may contribute to deficits in lean mass that many premature infants exhibit into adulthood.

Associations between stool micro-transcriptome, gut microbiota, and infant growth

Rapid infant growth increases the risk for adult obesity. The gut microbiome is associated with early weight status; however, no study has examined how interactions between microbial and host ribonucleic acid (RNA) expression influence infant growth. We hypothesized that dynamics in infant stool micro-ribonucleic acids (miRNAs) would be associated with both microbial activity and infant growth via putative metabolic targets. Stool was collected twice from 30 full-term infants, at 1 month and again between 6 and 12 months. Stool RNA were measured with high-throughput sequencing and aligned to human and microbial databases. Infant growth was measured by weight-for-length z-score at birth and 12 months. Increased RNA transcriptional activity of Clostridia (R = 0.55; Adj p = 3.7E-2) and Burkholderia (R = -0.820, Adj p = 2.62E-3) were associated with infant growth. Of the 25 human RNAs associated with growth, 16 were miRNAs. The miRNAs demonstrated significant target enrichment (Adj p < 0.05) for four metabolic pathways. There were four associations between growth-related miRNAs and growth-related phyla. We have shown that longitudinal trends in gut microbiota activity and human miRNA levels are associated with infant growth and the metabolic targets of miRNAs suggest these molecules may regulate the biosynthetic landscape of the gut and influence microbial activity.

PPARγ activation in late gestation does not promote surfactant maturation in the fetal sheep lung

Respiratory distress syndrome results from inadequate functional pulmonary surfactant and is a significant cause of mortality in preterm infants. Surfactant is essential for regulating alveolar interfacial surface tension, and its synthesis by Type II alveolar epithelial cells is stimulated by leptin produced by pulmonary lipofibroblasts upon activation by peroxisome proliferator-activated receptor γ (PPARγ). As it is unknown whether PPARγ stimulation or direct leptin administration can stimulate surfactant synthesis before birth, we examined the effect of continuous fetal administration of either the PPARγ agonist, rosiglitazone (RGZ; Study 1) or leptin (Study 2) on surfactant protein maturation in the late gestation fetal sheep lung. We measured mRNA expression of genes involved in surfactant maturation and showed that RGZ treatment reduced mRNA expression of LPCAT1 (surfactant phospholipid synthesis) and LAMP3 (marker for lamellar bodies), but did not alter mRNA expression of PPARγ, surfactant proteins (SFTP-A, -B, -C, and -D), PCYT1A (surfactant phospholipid synthesis), ABCA3 (phospholipid transportation), or the PPARγ target genes SPHK-1 and PAI-1. Leptin infusion significantly increased the expression of PPARγ and IGF2 and decreased the expression of SFTP-B. However, mRNA expression of the majority of genes involved in surfactant synthesis was not affected. These results suggest a potential decreased capacity for surfactant phospholipid and protein production in the fetal lung after RGZ and leptin administration, respectively. Therefore, targeting PPARγ may not be a feasible mechanistic approach to promote lung maturation.

Cord blood metabolic signatures predictive of childhood overweight and rapid growth

INTRODUCTION

Metabolomics may identify biological pathways predisposing children to the risk of overweight and obesity. In this study, we have investigated the cord blood metabolic signatures of rapid growth in infancy and overweight in early childhood in four European birth cohorts.

METHODS

Untargeted liquid chromatography-mass spectrometry metabolomic profiles were measured in cord blood from 399 newborns from four European cohorts (ENVIRONAGE, Rhea, INMA and Piccolipiu). Rapid growth in the first year of life and overweight in childhood was defined with reference to WHO growth charts. Metabolome-wide association scans for rapid growth and overweight on over 4500 metabolic features were performed using multiple adjusted logistic mixed-effect models and controlling the false discovery rate (FDR) at 5%. In addition, we performed a look-up analysis of 43 pre-annotated metabolites, previously associated with birthweight or rapid growth.

RESULTS

In the Metabolome-Wide Association Study analysis, we identified three and eight metabolites associated with rapid growth and overweight, respectively, after FDR correction. Higher levels of cholestenone, a cholesterol derivative produced by microbial catabolism, were predictive of rapid growth (p = 1.6 × 10-3). Lower levels of the branched-chain amino acid (BCAA) valine (p = 8.6 × 10-6) were predictive of overweight in childhood. The area under the receiver operator curve for multivariate prediction models including these metabolites and traditional risk factors was 0.77 for rapid growth and 0.82 for overweight, compared with 0.69 and 0.69, respectively, for models using traditional risk factors alone. Among the 43 pre-annotated metabolites, seven and five metabolites were nominally associated (P < 0.05) with rapid growth and overweight, respectively. The BCAA leucine, remained associated (1.6 × 10-3) with overweight after FDR correction.

CONCLUSION

The metabolites identified here may assist in the identification of children at risk of developing obesity and improve understanding of mechanisms involved in postnatal growth. Cholestenone and BCAAs are suggestive of a role of the gut microbiome and nutrient signalling respectively in child growth trajectories.

Biological basis of child health 6: development of the skeletal system and orthopaedic conditions

This article is the sixth in a series on the biological basis of child health. It provides an overview of the development of the skeletal system before and after birth, and outlines the potential congenital anomalies that may occur. The article explains the structure and function of the bones before describing the role of the joints, tendons and ligaments. It also outlines the presentation and management of some of the common orthopaedic conditions seen in infants and children, including fractures, osteogenesis imperfecta, scoliosis, juvenile idiopathic arthritis, developmental dysplasia of the hip and achondroplasia.

Neutrophil-Associated Inflammatory Changes in the Pre-Diabetic Pancreas of Early-Age NOD Mice

A growing body of evidence indicates that neutrophils are the first major leukocyte population accumulating inside the pancreas even before the onset of a lymphocytic-driven impairment of functional beta cells in type 1 diabetes mellitus (T1D). In humans, pancreata from T1D deceased donors exhibit significant neutrophil accumulation. We present a time course of previously unknown inflammatory changes that accompany neutrophil and neutrophil elastase accumulation in the pancreas of the non-obese diabetic (NOD) mouse strain as early as 2 weeks of age. We confirm earlier findings in NOD mice that neutrophils accumulate as early as 2 weeks of age. We also observe a concurrent increase in the expression of neutrophil elastase in this time period. We also detect components of neutrophil extracellular traps (NET) mainly in the exocrine tissue of the pancreas during this time as well as markers of vascular pathology as early as 2 weeks of age. Age- and sex-matched C57BL/6 mice do not exhibit these features inside the pancreas. When we treated NOD mice with inhibitors of myeloperoxidase and neutrophil elastase, two key effectors of activated neutrophil activity, alone or in combination, we were unable to prevent the progression to hyperglycemia in any manner different from untreated control mice. Our data confirm and add to the body of evidence demonstrating neutrophil accumulation inside the pancreas of mice genetically susceptible to T1D and also offer novel insights into additional pathologic mechanisms involving the pancreatic vasculature that have, until now, not been discovered inside the pancreata of these mice. However, inhibition of key neutrophil enzymes expressed in activated neutrophils could not prevent diabetes. These findings add to the body of data supporting a role for neutrophils in the establishment of early pathology inside the pancreas, independently of, and earlier from the time at onset of lymphocytic infiltration. However, they also suggest that inhibition of neutrophils alone, acting via myeloperoxidase and neutrophil elastase only, in the absence of other other effector cells, is insufficient to alter the natural course of autoimmune diabetes, at least in the NOD model of the disease.

An obesogenic maternal environment impairs mouse growth patterns, satellite cell activation, and markers of postnatal myogenesis

Skeletal muscle is sensitive to environmental cues that are first present in utero. Maternal overnutrition is a model of impaired muscle development leading to structural and metabolic dysfunction in adult life. In this study, we investigated the effect of an obesogenic maternal environment on growth and postnatal myogenesis in the offspring. Male C57BL/6J mice born to chow- or high-fat-diet-fed mothers were allocated to four different groups at the end of weaning. For the following 10 wk, half of the pups were maintained on the same diet as their mother and half of the pups were switched to the other diet (chow or high-fat). At 12 wk of age, muscle injury was induced using an intramuscular injection of barium chloride. Seven days later, mice were humanely killed and muscle tissue was harvested. A high-fat maternal diet impaired offspring growth patterns and downregulated satellite cell activation and markers of postnatal myogenesis 7 days after injury without altering the number of newly synthetized fibers over the whole 7-day period. Importantly, a healthy postnatal diet could not reverse any of these effects. In addition, we demonstrated that postnatal myogenesis was associated with a diet-independent upregulation of three miRNAs, mmu-miR-31-5p, mmu-miR-136-5p, and mmu-miR-296-5p. Furthermore, in vitro analysis confirmed the role of these miRNAs in myocyte proliferation. Our findings are the first to demonstrate that maternal overnutrition impairs markers of postnatal myogenesis in the offspring and are particularly relevant to today's society where the incidence of overweight/obesity in women of childbearing age is increasing.

SPRED proteins and their roles in signal transduction, development, and malignancy

The roles of SPRED proteins in signaling, development, and cancer are becoming increasingly recognized. SPRED proteins comprise an N-terminal EVH-1 domain, a central c-Kit-binding domain, and C-terminal SROUTY domain. They negatively regulate signaling from tyrosine kinases to the Ras-MAPK pathway. SPRED1 binds directly to both c-KIT and to the RasGAP, neurofibromin, whose function is completely dependent on this interaction. Loss-of-function mutations in SPRED1 occur in human cancers and cause the developmental disorder, Legius syndrome. Genetic ablation of SPRED genes in mice leads to behavioral problems, dwarfism, and multiple other phenotypes including increased risk of leukemia. In this review, we summarize and discuss biochemical, structural, and biological functions of these proteins including their roles in normal cell growth and differentiation and in human disease.

Testing for context-dependent effects of prenatal thyroid hormones on offspring survival and physiology: an experimental temperature manipulation

Maternal effects via hormonal transfer from the mother to the offspring provide a tool to translate environmental cues to the offspring. Experimental manipulations of maternally transferred hormones have yielded increasingly contradictory results, which may be explained by differential effects of hormones under different environmental contexts. Yet context-dependent effects have rarely been experimentally tested. We therefore studied whether maternally transferred thyroid hormones (THs) exert context-dependent effects on offspring survival and physiology by manipulating both egg TH levels and post-hatching nest temperature in wild pied flycatchers (Ficedula hypoleuca) using a full factorial design. We found no clear evidence for context-dependent effects of prenatal THs related to postnatal temperature on growth, survival and potential underlying physiological responses (plasma TH levels, oxidative stress and mitochondrial density). We conclude that future studies should test for other key environmental conditions, such as food availability, to understand potential context-dependent effects of maternally transmitted hormones on offspring, and their role in adapting to changing environments.

Type of early life adversity confers differential, sex-dependent effects on early maturational milestones in mice

Early life adversity (ELA) increases risk for negative health outcomes, with sex disparities in prevalence and form of ELA experienced and risk for neuropsychiatric pathology. ELA comes in many forms (e.g. parental neglect/loss, limited access to resources) but whether disparate forms of ELA have common effects on outcomes, and if males and females are equally affected, remains unknown. Epidemiological studies often fail to accurately account for differences in type, timing, and duration of adversity experienced. Rodent models allow precise control of many of these variables. However, differences in the form of ELA, species, strain, housing, and testing paradigms used may contribute to differences in outcomes leading to questions of whether differences are the result of the form of ELA or these other variables. Here, we directly compared two mouse models of ELA, maternal separation (MS) and limited bedding (LB) in males and females on development of the body, motor and visual milestones, stress physiology, and anxiety-like behavior. LB affected timing of early milestones, somatic growth, and stress physiology in both sexes, yet only females showed later anxiety-like behaviors. MS rearing affected males and females similarly in early milestone development, yet only males showed changes in stress physiology and anxiety-like outcomes. These studies provide a platform to directly compare MS and LB models within one lab. The current work advances our understanding of the unique features of ELA that shape early neurodevelopmental events and risk for later pathology, increasing the translational relevance of these ELA models.

Postpartum environmental challenges alter maternal responsiveness and offspring development

Because many threats exist in an animal's natural habitat, it is important to understand the impact of environmental challenges on maternal-offspring interactions and outcomes. In the current study, a rodent model incorporating the presence of restricted resources and an environmental threat (e.g. predator-related odors and sounds) was investigated. Specifically, pregnant females were assigned to one of four treatments: standard resources, without threat (SR; n = 7); standard resources plus threat (SR-T; n = 8); restricted resources, without threat (RR; n = 7); and restricted resources plus threat (RR-T; n = 6). Maternal rats were moved into the assigned conditions on postnatal day 2 and remained until pups were weaned. Following a standard pup retrieval task on postnatal days 2 and 6, maternal rats were exposed to a retrieval challenge task on postnatal day 8 in which each rat had to traverse a novel barrier to retrieve pups. For neurobiological measures of stress/resilience responsiveness, fecal samples were collected for detection of corticosterone and DHEA metabolites; additionally, immunohistochemistry was conducted on the maternal brains to indicate the presence of Neuropeptide Y (NPY) and Brain Derived Neurotrophic Factor (BDNF) immunoreactivity in the hippocampus, amygdala and hypothalamus. Pup development measures, including body weight and tail length, were also collected. Results suggest that maternal rats with restricted resources exhibited diminished maternal responsiveness that resulted in altered pup development measures; further, restricted resource rats exhibited endocrine markers of compromised emotional resilience (lower DHEA) and decreased neural markers of neuroplasticity (BDNF) and emotional resilience (NPY). Interestingly, predator threat affected various aspects of maternal-pup interactions but had no effect on neurobiological variables, suggesting that restricted resources had a more negative impact on maternal-related outcomes than the presence of predator threat.

Association of Poor Sanitation With Growth Measurements Among Children in India

Importance

Much research on sanitation and linear growth in low- and middle-income countries focuses on children younger than 5 years. However, poor sanitation may be associated with growth faltering during middle and late childhood to a greater extent than previously recognized.

Objective

To characterize the association of poor sanitation with height-for-age z (HAZ) scores in children and adolescents in India aged 0 to 18 years.

Design, Setting, and Participants

This cross-sectional study examined 134 882 children and adolescents aged 0 to 18 years who were surveyed in the fourth round of India's District Level Household and Facilities Survey (survey conducted August 2012 to February 2014). Data were analyzed from June 1, 2019, to August 20, 2019.

Exposures

Proportion of households reporting open defecation at the village level (to account for its high negative externality) and household-level access to boiled or filtered drinking water.

Main Outcomes and Measures

Individual-level HAZ scores were measured in standard deviations. The association of exposures with outcomes was estimated using ordinary least-squares regression stratified by sex (boys and girls) and 4 age groups (≤1, >1 to ≤7, >7 to ≤12, >12 to ≤18 years). Models controlled for parental height and education, socioeconomic status, maternal age at birth, hemoglobin level, and indicators for state and birth year to adjust for regional (state) and temporal (birth year) fixed effects.

Results

The sample comprised 70 463 male (52.5%) and 64 419 female (47.8%) children and adolescents aged 0 to 18 years; 46 722 participants (34.6%) were aged older than 12 to 18 years. Open defecation was inversely associated with HAZ score among all age groups except boys aged 1 year and younger (>1 to ≤7 years: β, -0.22; 95% CI, -0.35 to -0.10; >7 to ≤12 years: β, -0.15; 95% CI, -0.24 to -0.06; >12 to ≤18 years: β, -0.10; 95% CI, -0.19 to -0.01) and among girls aged between 7 and 18 years (>7 to ≤12 years: β, -0.22; 95% CI, -0.33 to -0.12; >12 to ≤18 years: β, -0.16; 95% CI, -0.23 to -0.09). Boiled or filtered drinking water was positively associated with HAZ score among younger girls (≤1 year: β, 0.26; 95% CI, 0.07 to 0.45; >1 to ≤7 years: β, 0.07; 95% CI, 0.01 to 0.14) and across all age groups in boys (≤1 years: β, 0.19; 95% CI, 0.03 to 0.35; >1 to ≤7 years: β, 0.07; 95% CI, 0.00 to 0.14; >7 to ≤12 years: β, 0.08; 95% CI, 0.03 to 0.13; >12 to ≤18 years: β, 0.06; 95% CI, 0.01 to 0.11).

Conclusions and Relevance

In this study, open defecation and lack of boiled or filtered drinking water were inversely associated with height-for-age measures across all ages in children and adolescents in India. Improved sanitation may benefit growth among children and adolescents older than 5 years.

Relationships between vocal pitch perception and production: a developmental perspective

The purpose of this study was to examine the relationships between vocal pitch discrimination abilities and vocal responses to auditory pitch-shifts. Twenty children (6.6-11.7 years) and twenty adults (18-28 years) completed a listening task to determine auditory discrimination abilities to vocal fundamental frequency (fo) as well as two vocalization tasks in which their perceived fo was modulated in real-time. These pitch-shifts were either unexpected, providing information on auditory feedback control, or sustained, providing information on sensorimotor adaptation. Children were subdivided into two groups based on their auditory pitch discrimination abilities; children within two standard deviations of the adult group were classified as having adult-like discrimination abilities (N = 11), whereas children outside of this range were classified as having less sensitive discrimination abilities than adults (N = 9). Children with less sensitive auditory pitch discrimination abilities had significantly larger vocal response magnitudes to unexpected pitch-shifts and significantly smaller vocal response magnitudes to sustained pitch-shifts. Children with less sensitive auditory pitch discrimination abilities may rely more on auditory feedback and thus may be less adept at updating their stored motor programs.

Energy balance but not competitive environment corresponds with allostatic load during development in an Old World monkey

Primates develop slowly relative to their body size, a pattern posited to result from ecological risk aversion. Little is known, however, about how energy balance contributes to allostatic load in juveniles. Using data collected over 8 consecutive months, we examined variation in energy balance (as measured by urinary C-peptide) and how energy balance, life history status, and social competition related to allostatic load (as measured by deviation from baseline fecal glucocorticoid metabolites, dfGCs) in 41 wild juvenile blue monkeys from 3 social groups. Juvenile energy balance was higher among females, older juveniles, when ripe fruit was more available, and when rainfall was lower. Energy balance, but not life history or competitive environments, predicted dfGC concentrations, such that juveniles generally had lower mean dfGCs when they had higher energy balance. An additional exploratory analysis of how dfGCs relate to social strategies revealed that subjects had lower dfGCs when they groomed less, and played more. Time spent grooming interacted with energy balance in predicting dfGC concentrations, so that individuals that groomed more actually had higher dfGCs when they had higher energy balance. Together these results reveal that energetic deficiencies are a true ecological risk factor in blue monkeys, and suggest that navigating the social environment via overt affiliative behavior is potentially both a stress-relieving and stress-inducing endeavor during development.

Prepubertal gonadectomy reveals sex differences in approach-avoidance behavior in adult mice

Adolescence is a developmental period that is associated with physical, cognitive, and affective maturation and a time when sex biases in multiple psychiatric diseases emerge. While puberty onset marks the initiation of adolescence, it is unclear whether the pubertal rise in gonadal hormones generates sex differences in approach-avoidance behaviors that may impact psychiatric vulnerability. To examine the influence of pubertal development on adult behavior, we removed the gonads or performed sham surgery in male and female mice just prior to puberty onset and assessed performance in an odor-guided foraging task and anxiety-related behaviors in adulthood. We observed no significant sex differences in foraging or anxiety-related behaviors between intact adult male and female mice but found significant differences between adult male and female mice that had been gonadectomized (GDX) prior to puberty onset. GDX males failed to acquire the odor-guided foraging task, showed reduced locomotion, and exhibited increased anxiety-like behavior, while GDX females showed the opposite pattern of behavior. These data suggest that puberty may minimize rather than drive differences in approach-avoidance phenotypes in male and female mice.

Growth Hormone(s), Testosterone, Insulin-Like Growth Factors, and Cortisol: Roles and Integration for Cellular Development and Growth With Exercise

Hormones are largely responsible for the integrated communication of several physiological systems responsible for modulating cellular growth and development. Although the specific hormonal influence must be considered within the context of the entire endocrine system and its relationship with other physiological systems, three key hormones are considered the "anabolic giants" in cellular growth and repair: testosterone, the growth hormone superfamily, and the insulin-like growth factor (IGF) superfamily. In addition to these anabolic hormones, glucocorticoids, mainly cortisol must also be considered because of their profound opposing influence on human skeletal muscle anabolism in many instances. This review presents emerging research on: (1) Testosterone signaling pathways, responses, and adaptations to resistance training; (2) Growth hormone: presents new complexity with exercise stress; (3) Current perspectives on IGF-I and physiological adaptations and complexity these hormones as related to training; and (4) Glucocorticoid roles in integrated communication for anabolic/catabolic signaling. Specifically, the review describes (1) Testosterone as the primary anabolic hormone, with an anabolic influence largely dictated primarily by genomic and possible non-genomic signaling, satellite cell activation, interaction with other anabolic signaling pathways, upregulation or downregulation of the androgen receptor, and potential roles in co-activators and transcriptional activity; (2) Differential influences of growth hormones depending on the "type" of the hormone being assayed and the magnitude of the physiological stress; (3) The exquisite regulation of IGF-1 by a family of binding proteins (IGFBPs 1-6), which can either stimulate or inhibit biological action depending on binding; and (4) Circadian patterning and newly discovered variants of glucocorticoid isoforms largely dictating glucocorticoid sensitivity and catabolic, muscle sparing, or pathological influence. The downstream integrated anabolic and catabolic mechanisms of these hormones not only affect the ability of skeletal muscle to generate force; they also have implications for pharmaceutical treatments, aging, and prevalent chronic conditions such as metabolic syndrome, insulin resistance, and hypertension. Thus, advances in our understanding of hormones that impact anabolic: catabolic processes have relevance for athletes and the general population, alike.

Evolutionary Strategies for Body Size

Humans show marked variation in body size around the world, both within and among populations. At present, the tallest people in the world are from the Netherlands and the Balkan countries, while the shortest populations are central African Pygmies. There are genetic, genetic plasticity, developmental, and environmental bases for size variation in Homo sapiens from the recent past and the present. Early populations of Homo species also have shown considerable size variation. Populations from the present and the past are also marked by sexual dimorphism, which, itself, shows group variation. There is abundant evidence for the effects of limited food and disease on human growth and resultant adult body size. This environmental influence has been reflected in "secular trends" (over a span of years) in growth and adult size from socioeconomic prosperity or poverty (availability of resources). Selective and evolutionary advantages of small or large body size also have been documented. Heritability for human height is relatively great with current genome-wide association studies (GWAS) identifying hundreds of genes leading to causes of growth and adult size variation. There are also endocrinological pathways limiting growth. An example is the reduced tissue sensitivity to human growth hormone (HGH) and insulin-like growth factor (IGF-1) in Philippine and African hunter-gatherer populations. In several short-statured hunter-gatherer populations (Asian, African, and South American), it has been hypothesized that short life expectancy has selected for early maturity and truncated growth to enhance fertility. Some island populations of humans and other mammals are thought to have been selected for small size because of limited resources, especially protein. The high-protein content of milk as a staple food may contribute to tall stature in East African pastoral peoples. These and other evolutionary questions linked to life history, male competition, reproduction, and mobility are explored in this paper.

Altered growth trajectory in children born to mothers with gestational diabetes mellitus and preeclampsia

PURPOSE

Gestational diabetes mellitus (GDM) and preeclampsia are leading causes of mortality and morbidity in mothers and children. High childhood body mass index (BMI) is among their myriad of negative outcomes. However, little is known about the trajectory of the child BMI exposed to GDM and co-occurring preeclampsia from early to mid-childhood. This study examined the independent and joint impact of GDM and preeclampsia on childhood BMI trajectory.

METHODS

A population-based sample of 356 mothers were recruited from OB/GYN clinics in New York. Their children were then followed annually from 18 to 72 months. Maternal GDM and preeclampsia status were obtained from medical records. Child BMI was calculated based on their height and weight at annual visits.

RESULTS

Hierarchical Linear Modeling was used to evaluate the trajectories of child BMI exposed to GDM and preeclampsia. BMI trajectory by GDM decreased (t ratio = - 2.24, [Formula: see text]0.45, 95% CI - 0.05-0.95, p = 0.07), but the trajectory by preeclampsia increased over time (t ratio = 3.153,[Formula: see text]0.65, 95% CI 0.11-1.18, p = 0.002). Moreover, there was a significant interaction between the two (t ratio = -2.24, [Formula: see text]- 1.244, 95% CI 0.15-2.33, p = 0.02), such that the BMI of children born to mothers with both GDM and preeclampsia showed consistent increases over time.

CONCLUSIONS

GDM and preeclampsia could be used as a marker for childhood obesity risk and the identification of a high-risk group, providing potential early intervention. These findings highlight the importance of managing obstetric complications, as an effective method of child obesity prevention.

Instant Ocean Versus Natural Seawater: Impacts on Aspects of Reproduction and Development in Three Marine Invertebrates

Marine invertebrate larvae have often been reared in artificial rather than natural seawater, either for convenience or to avoid potentially confounding effects of unknown contaminants. This study sought to determine the impact of artificial seawater on various aspects of development for three marine invertebrate species. We examined the impact of Instant Ocean on growth, survival, and fecundity of the deposit-feeding polychaete Capitella teleta at 2 salinities: 24 and 34 ppt; the impact on survival, growth rate, and time to metamorphic competence for the slipper limpet Crepidula fornicata; and the impact on larval growth for the sea star Asterias forbesi. Juveniles of C. teleta survived better in natural seawater than in Instant Ocean at both salinities but at the higher salinity grew more quickly in Instant Ocean; fecundity was not significantly affected by the type of seawater used at either salinity. Using Instant Ocean in place of natural seawater had no pronounced impact on the survival of C. fornicata larvae or on how long it took them to become competent to metamorphose; however, larvae grew somewhat more quickly in Instant Ocean than in natural seawater for the first 4 days of development, but by day 7 they were about 4.5% larger if they had been reared in seawater. The type of seawater used affected the growth of A. forbesi larvae, with larvae growing significantly more slowly in Instant Ocean than in natural seawater, no matter how growth was measured. In conclusion, our results suggest that although Instant Ocean may be a reasonable substitute for natural seawater for work with some species, using it may affect experimental outcomes in some aspects of work with other species.

Populus trichocarpa clade A PP2C protein phosphatases: their stress-induced expression patterns, interactions in core abscisic acid signaling, and potential for regulation of growth and development

Overexpression of the poplar PP2C protein phosphatase gene PtrHAB2 resulted in increased tree height and altered leaf morphology and phyllotaxy, implicating PP2C phosphatases as growth regulators functioning under favorable conditions. We identified and studied Populus trichocarpa genes, PtrHAB1 through PtrHAB15, belonging to the clade A PP2C family of protein phosphatases known to regulate abscisic acid (ABA) signaling. PtrHAB1 through PtrHAB3 and PtrHAB12 through PtrHAB15 were the most highly expressed genes under non-stress conditions. The poplar PP2C genes were differentially regulated by drought treatments. Expression of PtrHAB1 through PtrHAB3 was unchanged or downregulated in response to drought, while all other PtrHAB genes were weakly to strongly upregulated in response to drought stress treatments. Yeast two-hybrid assays involving seven ABA receptor proteins (PtrRCAR) against 12 PtrHAB proteins detected 51 interactions involving eight PP2Cs and all PtrRCAR proteins with 22 interactions requiring the addition of ABA. PtrHAB2, PtrHAB12, PtrHAB13 and PtrHAB14 also interacted with the sucrose non-fermenting related kinase 2 proteins PtrSnRK2.10 and PtrSnRK2.11, supporting conservation of a SnRK2 signaling cascade regulated by PP2C in poplar. Additionally, PtrHAB2, PtrHAB12, PtrHAB13 and PtrHAB14 interacted with the mitogen-activated protein kinase protein PtrMPK7. Due to its interactions with PtrSnRK2 and PtrMPK7 proteins, and its reduced expression during drought stress, PtrHAB2 was overexpressed in poplar to test its potential as a growth regulator under non-stress conditions. 35S::PtrHAB2 transgenics exhibited increased growth rate for a majority of transgenic events and alterations in leaf phyllotaxy and morphology. These results indicate that PP2Cs have additional roles which extend beyond canonical ABA signaling, possibly coordinating plant growth and development in response to environmental conditions.

Locomotion and posture development in immature male and female rats (Rattus norvegicus): Comparison of sensory-enriched versus sensory-deprived testing environments

The aim of the current study was to provide normative data on spontaneous locomotion and posture behavior in developing rats (Rattus norvegicus), during the first 2 postnatal weeks. Male and female rat pups were tested daily from P1 (postnatal day 1; ∼24 hr after birth) to P15 in a sensory-enriched or sensory-deprived testing environment, which was enclosed in a temperature-controlled incubator. Pups in the sensory-deprived condition were tested individually and placed in a square, Plexiglas box (open-field) for a 20-min test period. Pups in the sensory-enriched condition were placed in the same box with the siblings and bedding from the home cage to provide sensory stimulation that mimicked the home nest. Subjects in this condition were tested two at a time, with an additional two siblings (2 males and 2 females total in box). It was hypothesized that pups in the sensory-enriched testing condition would demonstrate more mature patterns of behavior, given the presence of behavior-activating sensory stimuli in the box. It was found that rat pups exhibited spontaneous pivoting and crawling as early as P1, regardless of sensory stimulation present in the testing environment. These behaviors were shown at least 1 to 3 days earlier than reported in prior studies. Quadrupedal walking occurred as early as P4 but was not reliably expressed until P10/11. These findings suggest that controlling temperature during testing influences the typical age of first occurrence of these behaviors. Finally, there were no sex differences in the duration of locomotion and posture behaviors. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Beyond the Bayley: Neurocognitive Assessments of Development During Infancy and Toddlerhood

The use of global, standardized instruments is conventional among clinicians and researchers interested in assessing neurocognitive development. Exclusively relying on these tests for evaluating effects may underestimate or miss specific effects on early cognition. The goal of this review is to identify alternative measures for possible inclusion in future clinical trials and interventions evaluating early neurocognitive development. The domains included for consideration are attention, memory, executive function, language, and socioemotional development. Although domain-based tests are limited, as psychometric properties have not yet been well-established, this review includes tasks and paradigms that have been reliably used across various developmental psychology laboratories.

Functional principal component analysis for identifying multivariate patterns and archetypes of growth, and their association with long-term cognitive development

For longitudinal studies with multivariate observations, we propose statistical methods to identify clusters of archetypal subjects by using techniques from functional data analysis and to relate longitudinal patterns to outcomes. We demonstrate how this approach can be applied to examine associations between multiple time-varying exposures and subsequent health outcomes, where the former are recorded sparsely and irregularly in time, with emphasis on the utility of multiple longitudinal observations in the framework of dimension reduction techniques. In applications to children’s growth data, we investigate archetypes of infant growth patterns and identify subgroups that are related to cognitive development in childhood. Specifically, “Stunting” and “Faltering” time-dynamic patterns of head circumference, body length and weight in the first 12 months are associated with lower levels of long-term cognitive development in comparison to “Generally Large” and “Catch-up” growth. Our findings provide evidence for the statistical association between multivariate growth patterns in infancy and long-term cognitive development.

Well-Child Visits for Infants and Young Children

The well-child visit allows for comprehensive assessment of a child and the opportunity for further evaluation if abnormalities are detected. A complete history during the well-child visit includes information about birth history; prior screenings; diet; sleep; dental care; and medical, surgical, family, and social histories. A head-to-toe examination should be performed, including a review of growth. Immunizations should be reviewed and updated as appropriate. Screening for postpartum depression in mothers of infants up to six months of age is recommended. Based on expert opinion, the American Academy of Pediatrics recommends developmental surveillance at each visit, with formal developmental screening at nine, 18, and 30 months and autism-specific screening at 18 and 24 months; the U.S. Preventive Services Task Force found insufficient evidence to make a recommendation. Well-child visits provide the opportunity to answer parents' or caregivers' questions and to provide age-appropriate guidance. Car seats should remain rear facing until two years of age or until the height or weight limit for the seat is reached. Fluoride use, limiting or avoiding juice, and weaning to a cup by 12 months of age may improve dental health. A one-time vision screening between three and five years of age is recommended by the U.S. Preventive Services Task Force to detect amblyopia. The American Academy of Pediatrics guideline based on expert opinion recommends that screen time be avoided, with the exception of video chatting, in children younger than 18 months and limited to one hour per day for children two to five years of age. Cessation of breastfeeding before six months and transition to solid foods before six months are associated with childhood obesity. Juice and sugar-sweetened beverages should be avoided before one year of age and provided only in limited quantities for children older than one year.

The absence of maternal pineal melatonin rhythm during pregnancy and lactation impairs offspring physical growth, neurodevelopment, and behavior

Maternal melatonin provides photoperiodic information to the fetus and thus influences the regulation and timing of the offspring's internal rhythms and preparation for extra-uterine development. There is clinical evidence that melatonin deprivation of both mother and fetus during pregnancy, and of the neonate during lactation, results in negative long-term health outcomes. As a consequence, we hypothesized that the absence of maternal pineal melatonin might determine abnormal brain programming in the offspring, which would lead to long-lasting implications for behavior and brain function. To test our hypothesis, we investigated in rats the effects of maternal melatonin deprivation during gestation and lactation (MMD) to the offspring and the effects of its therapeutic replacement. The parameters evaluated were: (1) somatic, physical growth and neurobehavioral development of pups of both sexes; (2) hippocampal-dependent spatial learning and memory of the male offspring; (3) adult hippocampal neurogenesis of the male offspring. Our findings show that MMD significantly delayed male offspring's onset of fur development, pinna detachment, eyes opening, eruption of superior incisor teeth, testis descent and the time of maturation of palmar grasp, righting reflex, free-fall righting and walking. Conversely, female offspring neurodevelopment was not affected. Later on, male offspring show that MMD was able to disrupt both spatial reference and working memory in the Morris Water Maze paradigm and these deficits correlate with changes in the number of proliferative cells in the hippocampus. Importantly, all the observed impairments were reversed by maternal melatonin replacement therapy. In summary, we demonstrate that MMD delays the appearance of physical features, neurodevelopment and cognition in the male offspring, and points to putative public health implications for night shift working mothers.

[Physical development and the age of fat reunion of Uygur and Han children under 7 years old in Urumuqi in 2015]

OBJECTIVE

To understand the physical development of Uygur and Han children under 7 years old in Urumuqi, and analyze the age of adiposity rebound.

METHODS

Using stratified cluster sampling, 9682 Uygur and Han children under 7 years old were selected in 7 districts and 1 county in Urumqi in June 2015, measuring their heights, weights, sitting heights, head circumference and chest circumference; comparingthe differences of weight for height Z-score( WHZ), drawing WHZ curves, calculating the adiposity rebound ages of Uygur and Han nationality boys and girls.

RESULTS

The difference of physical development in low age groups was significant. There were significant differences in the WHZ of Uygur and Han boys in 0 month-( t = 4. 277, P <0. 001), 6 months-( t = 2. 133, P = 0. 033), 5 years-( t = 2. 278, P = 0. 023), 6-7 years( t = 2. 503, P = 0. 013) and all ages combined( t = 5. 238, P < 0. 001), and significant differences exist in WHZ of Uygur and Han girls in 0 month-( t = 2. 533, P =0. 011) and 1 year old-( t =-2. 141, P = 0. 033). The overall prevalence of overweight and obesity in boys was higher than that in girls under 7 years old( overweight rate: Uygur boys 7. 97%, Uygur girls 5. 46%; Han boys 12. 55%, Han girls 5. 90%; obesity rate:Uygur boys 5. 58%, Uygur girls 3. 48%; Han boys 7. 73%, Han girls 3. 92%), while overweight obesity ratio( OOR) in Uygur girls were higher than Uygur boys( girls OOR =1. 57, boys OOR = 1. 43) and OOR of Han girls was lower than that of boys( girls OOR =1. 50, boys OOR = 1. 62). Mathematical model indicated that the adiposity rebound age of Han boys was 3. 94 years old( 95% CI 3. 54-4. 33), Uygur boys was 4. 17 years old( 95% CI 2. 70-5. 72) and Han girls was 4. 56 years old( 95% CI 4. 14-4. 99), and the adiposity rebound age of Uygur girls was 5. 57 years old( 95% CI 4. 00-7. 13).

CONCLUSION

The prevalence of overweight and obesity among Han children under seven years old is higher than that of Uygur children, and the age of fat rebound in Han children is earlier than that of Uygur children.

Polycystic ovary syndrome throughout a woman's life

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-aged women and the main cause of infertility due to anovulation. However, this syndrome spans the lives of women affecting them from in-utero life until death, leading to several health risks that can impair quality of life and increase morbidity and mortality rates. Fetal programming may represent the beginning of the condition characterized by hyperandrogenism and insulin resistance which leads to a series of medical consequences in adolescence, adulthood, and old age. Menstrual and fertility problems evolve into metabolic complications as age advances. An early and precise diagnosis is important for an adequate management of PCOS, especially at the extreme ends of the reproductive lifespan. However, many different phenotypes are included under the same condition, being important to look at these different phenotypes separately, as they may require different treatments and have different consequences. In this way, PCOS exhibits a great metabolic complexity and its diagnosis needs to be revised once again and adapted to recent data obtained by new technologies. According to the current medical literature, lifestyle therapy constitutes the first step in the management, especially when excess body weight is associated. Pharmacotherapy is frequently used to treat the most predominant manifestations in each age group, such as irregular menses and hirsutism in adolescence, fertility problems in adulthood, and metabolic problems and risk of cancer in old age. Close surveillance is mandatory in each stage of life to avoid health risks which may also affect the offspring, since fetal and post-natal complications seem to be increased in PCOS women.

Sertoli Cell Number Defines and Predicts Germ and Leydig Cell Population Sizes in the Adult Mouse Testis

Sertoli cells regulate differentiation and development of the testis and are essential for maintaining adult testis function. To model the effects of dysregulating Sertoli cell number during development or aging, we have used acute diphtheria toxin-mediated cell ablation to reduce Sertoli cell population size. Results show that the size of the Sertoli cell population that forms during development determines the number of germ cells and Leydig cells that will be present in the adult testis. Similarly, the number of germ cells and Leydig cells that can be maintained in the adult depends directly on the size of the adult Sertoli cell population. Finally, we have used linear modeling to generate predictive models of testis cell composition during development and in the adult based on the size of the Sertoli cell population. This study shows that at all ages the size of the Sertoli cell population is predictive of resulting testicular cell composition. A reduction in Sertoli cell number/proliferation at any age will therefore lead to a proportional decrease in germ cell and Leydig cell numbers, with likely consequential effects on fertility and health.

Effects of developmental conditions on glucocorticoid concentrations in adulthood depend on sex and foraging conditions

Developmental conditions in early life frequently have long-term consequences on the adult phenotype, but the adult environment can modulate such long-term effects. Glucocorticoid hormones may be instrumental in mediating developmental effects, but the permanency of such endocrine changes is still debated. Here, we manipulated environmental conditions during development (small vs. large brood size, and hence sibling competition) and in adulthood (easy vs. hard foraging conditions) in a full factorial design in zebra finches, and studied effects on baseline (Bas-CORT) and stress-induced (SI-CORT) corticosterone in adulthood. Treatments affected Bas-CORT in females, but not in males. Females reared in small broods had intermediate Bas-CORT levels as adults, regardless of foraging conditions in adulthood, while females reared in large broods showed higher Bas-CORT levels in hard foraging conditions and lower levels in easy foraging conditions. Female Bas-CORT was also more susceptible than male Bas-CORT to non-biological variables, such as ambient temperature. In line with these results, repeatability of Bas-CORT was higher in males (up to 51%) than in females (25%). SI-CORT was not responsive to the experimental manipulations in either sex and its repeatability was high in both sexes. We conclude that Bas-CORT responsiveness to intrinsic and extrinsic conditions is higher in females than in males, and that the expression of developmental conditions may depend on the adult environment. The latter finding illustrates the critical importance of studying of causes and consequences of long-term developmental effects in other environments in addition to standard laboratory conditions.

Effects of early life adversity on cortisol/salivary alpha-amylase symmetry in free-ranging juvenile rhesus macaques

Early life adversity (ELA) affects physiological and behavioral development. One key component is the relationship between the developing Hypothalamic-Pituitary-Adrenal (HPA) axis and the Sympathetic Nervous System (SNS). Recent studies suggest a relationship between early life adversity and asymmetry in cortisol (a measure of HPA activation) and salivary alpha-amylase (sAA: a correlate of SNS activation) responses to stress among human children, but to our knowledge there have been no comparable studies in nonhumans. Here, we investigate the responses of these two analytes in "low stress" and "high stress" situations in free-ranging juvenile rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico. Behavioral data on maternal maltreatment were collected during the first 3months of life to determine individual rates of ELA, and saliva samples were collected from subjects noninvasively during juvenility. Irrespective of ELA, salivary alpha-amylase levels were lower in low stress situations and higher in high stress situations. For cortisol however, high ELA subjects exhibited higher low stress concentrations and blunted acute responses during high stress situations compared to moderate and low ELA subjects. Cortisol and sAA values were positively correlated among low ELA subjects, suggesting symmetry, but were uncorrelated or negatively correlated among moderate and high ELA subjects, suggesting asymmetry in these individuals. These findings indicate dysregulation of the stress response among juveniles maltreated during infancy: specifically, attenuated cortisol reactivity coupled with typical sAA reactivity characterize the stress response profiles of juveniles exposed to higher rates of ELA during the first 3months of life.

Impact of peanut consumption in the LEAP Study: Feasibility, growth, and nutrition

BACKGROUND

Early introduction of peanut is an effective strategy to prevent peanut allergy in high-risk infants; however, feasibility and effects on growth and nutritional intake are unknown.

OBJECTIVE

We sought to evaluate the feasibility of introducing peanut in infancy and explore effects on growth and nutritional intake up to age 60 months.

METHODS

In the Learning Early About Peanut Allergy trial, 640 atopic infants aged 4 to 11 months were randomly assigned to consume (6 g peanut protein per week) or avoid peanut until age 60 months. Peanut consumption and early feeding practices were assessed by questionnaire. Dietary intake was evaluated with prospective food diaries. Anthropometric measurements were taken at all study visits.

RESULTS

Peanut was successfully introduced and consumed until 60 months, with median peanut protein intake of 7.5 g/wk (interquartile range, 6.0-9.0 g/wk) in the consumption group compared with 0 g in the avoidance group. Introduction of peanut in breast-feeding infants did not affect the duration of breast-feeding. There were no differences in anthropometric measurements or energy intakes between groups at any visits. Regular peanut consumption led to differences in dietary intakes. Consumers had higher intakes of fat and avoiders had higher carbohydrate intakes; differences were greatest at the upper quartiles of peanut consumption. Protein intakes remained consistent between groups.

CONCLUSIONS

Introduction of peanut proved feasible in infants at high risk of peanut allergy and did not affect the duration of breast-feeding nor impact negatively on growth or nutrition. Energy balance was achieved in both groups through variations in intakes from fat and carbohydrate while protein homeostasis was maintained.

Height and calories in early childhood

This paper estimates a height production function using data from a randomized nutrition intervention conducted in rural Guatemala from 1969 to 1977. Using the experimental intervention as an instrument, the IV estimates of the effect of calories on height are an order of magnitude larger than the OLS estimates. Information from a unique measurement error process in the calorie data, counterfactuals results from the estimated model and external evidence from migration studies suggest that IV is not identifying a policy relevant average marginal impact of calories on height. The preferred, attenuation bias corrected OLS estimates from the height production function suggest that, averaging over ages, a 100 calorie increase in average daily calorie intake over the course of a year would increase height by 0.06 cm. Counterfactuals from the model imply that calories gaps in early childhood can explain at most 16% of the height gap between Guatemalan children and the US born children of Guatemalan immigrants.

Reducing Adiposity in a Critical Developmental Window Has Lasting Benefits in Mice

Although most adults can lose weight by dieting, a well-characterized compensatory decrease in energy expenditure promotes weight regain more than 90% of the time. Using mice with impaired hypothalamic leptin signaling as a model of early-onset hyperphagia and obesity, we explored whether this unfavorable response to weight loss could be circumvented by early intervention. Early-onset obesity was associated with impairments in the structure and function of brown adipose tissue mitochondria, which were ameliorated by weight loss at any age. Although decreased sympathetic tone in weight-reduced adults resulted in net reductions in brown adipose tissue thermogenesis and energy expenditure that promoted rapid weight regain, this was not the case when dietary interventions were initiated at weaning. Enhanced energy expenditure persisted even after mice were allowed to resume overeating, leading to lasting reductions in adiposity. These findings reveal a time window when dietary interventions can produce metabolic improvements that are stably maintained.

[Cognitive and brain development of memory from infancy to early adulthood]

Cognitive and brain development are closely linked from infancy to adulthood. The purpose of this article is to review the current state of knowledge on behavioral and brain substrates of memory development. First, we will review cognitive development of different memory systems, from procedural to autobiographical memory. We will discuss how the development of other cognitive functions (language, attention, executive functions and metamemory) participates in memory development. Second, we will describe how structural and functional changes in two core brain regions of memory, i.e. the hippocampus and the prefrontal cortex, impact the protracted development of memory throughout childhood.

Sleep/Wake Dynamics Changes during Maturation in Rats

Objectives

Conventional scoring of sleep provides little information about the process of transitioning between vigilance states. We applied the state space technique (SST) using frequency band ratios to follow normal maturation of different sleep/wake states, velocities of movements, and transitions between states of juvenile (postnatal day 34, P34) and young adult rats (P71).

Design

24-h sleep recordings of eight P34 and nine P71 were analyzed using conventional scoring criteria and SST one week following implantation of telemetric transmitter. SST is a non-categorical approach that allows novel quantitative and unbiased examination of vigilance-states dynamics and state transitions. In this approach, behavioral changes are described in a 2-dimensional state space that is derived from spectral characteristics of the electroencephalography.

Measurements and Results

With maturation sleep intensity declines, the duration of deep slow wave sleep (DSWS) and light slow wave sleep (LSWS) decreases and increases, respectively. Vigilance state determination, as a function of frequency, is not constant; there is a substantial shift to higher ratio 1 in all vigilance states except DSWS. Deep slow wave sleep decreases in adult relative to juvenile animals at all frequencies. P71 animals have 400% more trajectories from Wake to LSWS (p = 0.005) and vice versa (p = 0.005), and 100% more micro-arousals (p = 0.021), while trajectories from LSWS to DSWS (p = 0.047) and vice versa (p = 0.033) were reduced by 60%. In both juvenile and adult animals, no significant changes were found in sleep velocity at all regions of the 2-dimensional state space plot; suggesting that maturation has a partial effect on sleep stability.

Conclusions

Here, we present novel and original evidence that SST enables visualization of vigilance-state intensity, transitions, and velocities that were not evident by traditional scoring methods. These observations provide new perspectives in sleep state dynamics and highlight the usefulness of this technique in exploring the development of sleep-wake activity.

Perception of everyday sounds: a developmental study of a free sorting task

OBJECTIVES

The analysis of categorization of everyday sounds is a crucial aspect of the perception of our surrounding world. However, it constitutes a poorly explored domain in developmental studies. The aim of our study was to understand the nature and the logic of the construction of auditory cognitive categories for natural sounds during development. We have developed an original approach based on a free sorting task (FST). Indeed, categorization is fundamental for structuring the world and cognitive skills related to, without having any need of the use of language. Our project explored the ability of children to structure their acoustic world, and to investigate how such structuration matures during normal development. We hypothesized that age affects the listening strategy and the category decision, as well as the number and the content of individual categories.

DESIGN

Eighty-two French children (6-9 years), 20 teenagers (12-13 years), and 24 young adults participated in the study. Perception and categorization of everyday sounds was assessed based on a FST composed of 18 different sounds belonging to three a priori categories: non-linguistic human vocalizations, environmental sounds, and musical instruments.

RESULTS

Children listened to the sounds more times than older participants, built significantly more classes than adults, and used a different strategy of classification. We can thus conclude that there is an age effect on how the participants accomplished the task. Analysis of the auditory categorization performed by 6-year-old children showed that this age constitutes a pivotal stage, in agreement with the progressive change from a non-logical reasoning based mainly on perceptive representations to the logical reasoning used by older children. In conclusion, our results suggest that the processing of auditory object categorization develops through different stages, while the intrinsic basis of the classification of sounds is already present in childhood.

Strength and precision of neurotransmission at mammalian presynaptic terminals

Classically, the basic concept of chemical synaptic transmission was established at the frog neuromuscular junction, and direct intracellular recordings from presynaptic terminals at the squid giant presynaptic terminal have further clarified principles of neurotransmitter release. More recently, whole-cell patch-camp recordings from the calyx of Held in rodent brainstem slices have extended the classical concept to mammalian synapses providing new insights into the mechanisms underlying strength and precision of neurotransmission and developmental changes therein. This review summarizes findings from our laboratory and others on these subjects, mainly at the calyx of Held, with a particular focus on precise, high-fidelity, fast neurotransmission. The mechanisms by which presynaptic terminals acquire strong, precise neurotransmission during postnatal development are also discussed.

Early-Life Environmental Exposures and Height, Hypertension, and Cardiovascular Risk Factors Among Older Adults in India

Environmental exposures like rainfall and temperature influence infectious disease exposure and nutrition, two key early-life conditions linked to later-life health. However, few tests of whether early-life environmental exposures impact adult health have been performed, particularly in developing countries. This study examines the effects of experiencing rainfall and temperature shocks during gestation and up through the first four years after birth on measured height, hypertension, and other cardiovascular risk factors using data on adults aged 50 and above (N = 1,036) from the 2007-2008 World Health Organization Study on Global Ageing and Adult Health (SAGE) and district-level meteorological data from India. Results from multivariate logistic regressions show that negative rainfall shocks during gestation and positive rainfall shocks during the postbirth period increase the risk of having adult hypertension and CVD risk factors. Exposure to negative rainfall shocks and positive temperature shocks in the postbirth period increases the likelihood of falling within the lowest height decile. Prenatal shocks may influence nutrition in utero, while postnatal shocks may increase exposure to infectious diseases and malnutrition. The results suggest that gestation and the first two years after birth are critical periods when rainfall and temperature shocks take on increased importance for adult health.

Small organelle, big responsibility: the role of centrosomes in development and disease

The centrosome, a key microtubule organizing centre, is composed of centrioles, embedded in a protein-rich matrix. Centrosomes control the internal spatial organization of somatic cells, and as such contribute to cell division, cell polarity and migration. Upon exiting the cell cycle, most cell types in the human body convert their centrioles into basal bodies, which drive the assembly of primary cilia, involved in sensing and signal transduction at the cell surface. Centrosomal genes are targeted by mutations in numerous human developmental disorders, ranging from diseases exclusively affecting brain development, through global growth failure syndromes to diverse pathologies associated with ciliary malfunction. Despite our much-improved understanding of centrosome function in cellular processes, we know remarkably little of its role in the organismal context, especially in mammals. In this review, we examine how centrosome dysfunction impacts on complex physiological processes and speculate on the challenges we face when applying knowledge generated from in vitro and in vivo model systems to human development.

MicroRNAs: history, biogenesis, and their evolving role in animal development and disease

The discovery of microRNAs (miRNAs) in 1993 followed by developments and discoveries in small RNA biology have redefined the biological landscape by significantly altering the longstanding dogmas that defined gene regulation. These small RNAs play a significant role in modulation of an array of physiological and pathological processes ranging from embryonic development to neoplastic progression. Unique miRNA signatures of various inherited, metabolic, infectious, and neoplastic diseases have added a new dimension to the studies that look at their pathogenesis and highlight their potential to be reliable biomarkers. Also, altering miRNA functionality and the development of novel in vivo delivery systems to achieve targeted modulation of specific miRNA function are being actively pursued as novel approaches for therapeutic intervention in many diseases. Here we review the current body of knowledge on the role of miRNAs in development and disease and discuss future implications.

Somatic growth and lung function in sickle cell disease

Somatic growth is a key indicator of overall health and well-being with important prognostic implications in the management of chronic disease. Worldwide studies of growth in children and adults with SCD have predominantly shown delayed growth (especially in terms of body weight) that is gradual and progressive in nature. However, more recent studies have shown that a substantial number of patients with SCD have normal weight gain whereas some are even obese. Height in patients with SCD is not universally affected even among those with suboptimal weight gain, whereas some achieve the same or greater height than healthy controls. The relationship between somatic growth and lung function in SCD is not yet clearly defined. As a group, patients with SCD tend to have lower lung volumes compared with healthy controls. These findings are similar across the age spectrum and across ethnic/racial lines regardless of the differences in body weight. Several mechanisms and risk factors have been proposed to explain these findings. These include malnutrition, racial differences and socioeconomic status. In addition, there are structural changes of the thorax (specifically the anterio-posterior chest diameter and anterio-posterior to lateral chest ratio) specific to sickle cell disease, that potentially interfere with normal lung growth. Although, caloric and protein intake have been shown to improve both height and weight, the composition of an optimal diet remains unclear. The following article reviews the current knowledge and controversies regarding somatic growth and its relationship with lung function in sickle cell disease (SCD) as well as the role of specific deficiencies of certain micronutrients.

[The peculiarities of calcium metabolism regulation in different periods of growth and development]

The review contains literature data about calcium metabolism regulation in different periods of growth and development. The analyses of retrospective and current sources of information about the regulation of calcium homeostasis under the theory of functional systems, the regulation of calcium metabolism in prenatal and postnatal periods of the development, the significance of calcium metabolism disturbances in the development of pathological conditions were showed.

Are the 2006 World Health Organization standards for infant growth applicable to Hong Kong Chinese? Universalistic standards or epidemiological transition stage-specific norms

1. Parental socio-economic status was positively associated with length and body mass index of Hong Kong Chinese infants at 9 months. 2. Maternal smoking in pregnancy was negatively associated with infant length at 9 months. 3. Some of the World Health Organization (WHO) criteria for an optimal nurturing environment contributed positively to growth. At 36 months, Hong Kong Chinese infants were generally shorter and fatter than the WHO growth references.

Lifelong caloric restriction increases working memory in mice

Caloric restriction (CR) is argued to positively affect general health, longevity and the normally occurring age-related reduction of cognition. This issue is well examined, but most studies investigated the effect of short-term periods of CR. Herein, 4 weeks old female mice were fed caloric restricted for 4, 20 and especially for 74 weeks. CR mice received 60% of food eaten by their ad libitum (AL) fed littermates, and all age-matched groups were behaviorally analyzed. The motor coordination, which was tested by rotarod/accelerod, decreased age-related, but was not influenced by the different periods of CR. In contrast, the age-related impairment of spontaneous locomotor activity and anxiety, both being evaluated by open field and by elevated plus maze test, was found aggravated by a lifelong CR. Measurement of cognitive performance with morris water maze showed that the working memory decreased age-related in AL mice, while a lifelong CR caused a better cognitive performance and resulted in a significantly better spatial memory upon 74 weeks CR feeding. However, a late-onset CR feeding in 66 weeks old mice did not ameliorate the working memory. Therefore, a lifelong CR seems to be necessary to improve working memory.

Metamorphosis revealed: time-lapse three-dimensional imaging inside a living chrysalis

Studies of model insects have greatly increased our understanding of animal development. Yet, they are limited in scope to this small pool of model species: a small number of representatives for a hyperdiverse group with highly varied developmental processes. One factor behind this narrow scope is the challenging nature of traditional methods of study, such as histology and dissection, which can preclude quantitative analysis and do not allow the development of a single individual to be followed. Here, we use high-resolution X-ray computed tomography (CT) to overcome these issues, and three-dimensionally image numerous lepidopteran pupae throughout their development. The resulting models are presented in the electronic supplementary material, as are figures and videos, documenting a single individual throughout development. They provide new insight and details of lepidopteran metamorphosis, and allow the measurement of tracheal and gut volume. Furthermore, this study demonstrates early and rapid development of the tracheae, which become visible in scans just 12 h after pupation. This suggests that there is less remodelling of the tracheal system than previously expected, and is methodologically important because the tracheal system is an often-understudied character system in development. In the future, this form of time-lapse CT-scanning could allow faster and more detailed developmental studies on a wider range of taxa than is presently possible.

Mysteries of development. Under development

Much of what we know about the journey from single cell to mature organism involves what happens when things go awry. Here are five more mysteries of what happens when genes are working as they should.

Earlier development of analytical than holistic object recognition in adolescence

BACKGROUND

Previous research has shown that object recognition may develop well into late childhood and adolescence. The present study extends that research and reveals novel differences in holistic and analytic recognition performance in 7-12 year olds compared to that seen in adults. We interpret our data within a hybrid model of object recognition that proposes two parallel routes for recognition (analytic vs. holistic) modulated by attention.

METHODOLOGY/PRINCIPAL FINDINGS

Using a repetition-priming paradigm, we found in Experiment 1 that children showed no holistic priming, but only analytic priming. Given that holistic priming might be thought to be more 'primitive', we confirmed in Experiment 2 that our surprising finding was not because children's analytic recognition was merely a result of name repetition.

CONCLUSIONS/SIGNIFICANCE

Our results suggest a developmental primacy of analytic object recognition. By contrast, holistic object recognition skills appear to emerge with a much more protracted trajectory extending into late adolescence.

Effect of obesity on linear growth

PURPOSE OF REVIEW

To describe our current understanding of the mechanisms involved in the regulation of linear growth in childhood obesity.

RECENT FINDINGS

The developmental origins hypothesis has focused on low birth weight individuals with subsequent obesity, identifying a cascade of neuroendocrine regulatory factors involved in the progressive increase in body fat and metabolic risk. Yet, tall stature is the common clinical outcome of childhood obesity. Recent data have expanded our understanding of environmental influences on developing systems. Here, we review the elements of neuroendocrine systems contributing to the integration of metabolic controls involved in growth regulation in the obese child with particular emphasis on growth hormone, ghrelin, insulin-like growth factors and insulin.

SUMMARY

Growth patterns of obesity during childhood are well described, documenting increased linear growth in early childhood associated with accelerated pubertal maturation resulting in normal adult height. Despite recent data suggesting that ghrelin and the growth hormone secretagogue receptor, as well as the insulin-like growth factors, their binding proteins and insulin have potential to be mediators of nutrient exposure and linear growth, it remains to be determined how these systems interrelate and determine growth. This is an area of ongoing investigation.