Search

Purpose It is well known that pubertal timing affects adolescents' externalizing behaviors, but it is unknown if this effect lasts into adulthood. This study assessed if and when the early maturation effect wanes, specifically in two domains of externalizing behaviors: nonviolent and violent behaviors. Methods Using data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) that include age-appropriate items of violent and nonviolent behaviors assessed from ages 11–30 over four waves (N = 4,255), we conducted a series of longitudinal growth curve analyses to evaluate the effect of pubertal timing on the trajectories of nonviolent and violent externalizing behaviors for males and females. Results Compared to later maturing male peers, early maturing males reported significantly elevated overall externalizing, nonviolent, and violent behaviors throughout adolescence, but became indistinguishable from on-time and late-maturing counterparts in young adulthood. Similarly, early maturing females showed higher levels of overall externalizing and nonviolent behaviors than later maturing counterparts, but no effect of pubertal timing was seen on the trajectories of violent behaviors. However, early maturing females' overall externalizing and nonviolent behaviors also became indistinguishable from on-time and late-maturing females after adolescence. Conclusions These findings clarify the differential effect of early maturation on nonviolent and violent behaviors, especially in females, and highlight the short-lived nature of the effects of early pubertal timing.

Rodent pups emit ultrasonic vocalizations (USVs) to solicit maternal behavior, promoting their survival. Conversely, maternal behaviors affect the expression of pup USVs. We previously demonstrated that a maternal diet high in saturated fat (HFD) alters maternal behavior and is associated with early maturation of pups and their stress physiology. Here, we assessed the developmental profiles of pup USVs using quantitative and qualitative measures on postnatal days (PND)7 and 13. Quantitative measures included call counts, duration, and frequency, while qualitative measures examined calls' sonographic structures. HFD offspring lacked the typical decrease in USV numbers with age observed among control offspring. They also had shorter calls at PND7 compared to control and HFD offspring at PND13. HFD female offspring showed a greater number of one-frequency-sweep calls, while male pups showed a greater number of two-frequency-sweep calls compared to control offspring. Concomitantly, HFD dams showed impaired pup retrieval on PND7. The data suggest that fewer USVs of shorter duration in HFD offspring may alter dam solicitation and thus impair maternal pup retrieval. This study highlights the impacts of perinatal HFD exposure on the dyadic reciprocal interaction between dam and pups, which may set the stage for long-lasting effects on offspring physiology and behavior.

There is a growing interest in knowing the relationship between biological maturation and sport performance-related variables of young athletes. The objective of this study is to analyze the relationship between biological maturation, physical fitness, and kinanthropometric variables of athletes during their growing period, according to their sex. The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and the search protocol was registered in PROSPERO, code: CRD42020208397. A search through the PubMed, Web of Sciences, and EBSCO databases was performed. A total of 423 studies were screened and 13 were included in the meta-analysis. The meta-analysis was completed by using the mean and standard deviation of each variable according to each maturation status (early, on time, or late). Differences depending on maturation were found on physical fitness, with better results in the advanced maturational groups in the male population (standard mean difference (SMD) = 0.17–2.31; p < 0.001–0.05). Differences depending on maturation were found for kinanthropometric variables in males (SMD = 0.37–2.31; p < 0.001–0.002) and height and body mass in females (SMD = 0.96–1.19; p < 0.001). In conclusion, the early maturation group showed higher values in kinanthropometric variables and better results in physical fitness, highlighting the importance of the maturational process in the talent selection programs. Despite that, more research is needed to clarify the relationship of maturation with the other variables on female populations and the changes in the muscle and bone variables during the maturation processes of both sexes.

Vision develops rapidly during infancy, yet how visual cortex is organized during this period is unclear. One possibility is that the retinotopic organization of visual cortex emerges gradually as perceptual abilities improve. This may result in a hierarchical maturation of visual areas from striate to extrastriate cortex. Another possibility is that retinotopic organization is present from early infancy. This early maturation of area boundaries and tuning could scaffold further developmental changes. Here we test the functional maturity of infant visual cortex by performing retinotopic mapping with fMRI. Infants aged 5–23 months had retinotopic maps, with alternating preferences for vertical and horizontal meridians indicative of area boundaries from V1 to V4, and an orthogonal gradient of preferences from high to low spatial frequencies indicative of growing receptive field sizes. Although present in the youngest infants, these retinotopic maps showed subtle agerelated changes, suggesting that early maturation undergoes continued refinement.

OBJECTIVEThe acquisition and refinement of cognitive and behavioral skills during development is associated with the maturation of various brain oscillatory activities. Most developmental investigations have identified distinct patterns of low-frequency electrophysiological activity that are characteristic of various behavioral milestones. In this investigation, the authors focused on the cross-sectional developmental properties of high-frequency spectral power from the brain’s default mode network (DMN) during goal-directed behavior.METHODSThe authors contrasted regionally specific, time-evolving high gamma power (HGP) in the lateral DMN cortex between 3 young children (age range 3–6 years) and 3 adults by use of electrocorticography (ECoG) recordings over the left perisylvian cortex during a picture-naming task.RESULTSAcross all participants, a nearly identical and consistent response suppression of HGP, which is a functional signature of the DMN, was observed during task performance recordings acquired from ECoG electrodes placed over the lateral DMN cortex. This finding provides evidence of relatively early maturation of the DMN. Furthermore, only HGP relative to evoked alpha and beta band power showed this level of consistency across all participants.CONCLUSIONSRegionally specific, task-evoked suppression of the high-frequency components of the cortical power spectrum is established early in brain development, and this response may reflect the early maturation of specific cognitive and/or computational mechanisms.

Pubertal timing matters for psychological development. Early maturation in girls is linked to risk for depression and externalizing problems in adolescence and possibly adulthood, and early and late maturation in boys are linked to depression. It is unclear whether pubertal timing uniquely predicts problems; it might instead mediate the continuity of behavior problems from childhood to adolescence or create psychological risk specifically in youth with existing problems, thus moderating the link. We investigated these issues in 534 girls and 550 boys, measuring pubertal timing by a logistic model fit to annual self-report measures of development and, in girls, age at menarche. Prepuberty internalizing and externalizing behavior problems were reported by parents. Adolescent behavior problems were reported by parents and youth. As expected, behavior problems were moderately stable. Pubertal timing was not predicted by childhood problems, so it did not mediate the continuity of behavior problems from childhood to adolescence. Pubertal timing did not moderate links between early and later problems for girls. For boys, early maturation accentuated the link between childhood problems and adolescent substance use. Overall, the replicated links between puberty and behavior problems appear to reflect the unique effects of puberty and child behavior problems on the development of adolescent behavior problems.

The use of gonadotropin-releasing hormone analogs (GnRHa) for the treatment of central precocious puberty (CPP), especially in girls, has increased rapidly in recent years. In the context of a secular trend towards earlier puberty onset, many girls now treated for CPP are healthy children experiencing puberty onset within the early end of the normal range. Justifications for GnRHa treatment include the preservation of adult height (AH) potential and the alleviation of presumed distress of early maturation and menarche. With a case of a family requesting treatment for an 8-year-old girl in early puberty as a background, studies of the effect of untreated CPP and of GnRHa treatment of CPP on AH are reviewed. In addition, the limited evidence relating CPP to significant psychological distress – in part due to early menses, and for the amelioration of such distress by GnRHa treatment – is discussed. Taken together, current information suggests that for girls with mildly early onset of puberty (ages 7–9 years), an informed assent discussion with the family should include the consideration of reassurance and observation for many girls who might otherwise receive 2–4 years of GnRHa treatment for a poorly defined benefit and at a cost of at least $20–30,000 per year.

The first year of life is a key period of brain development, characterized by dramatic structural and functional modifications. Here, we measured rest cerebral blood flow (CBF) modifications throughout babies’ first year of life using arterial spin labeling magnetic resonance imaging sequence in 52 infants, from 3 to 12 months of age. Overall, global rest CBF significantly increased during this age span. In addition, we found marked regional differences in local functional brain maturation. While primary sensorimotor cortices and insula showed early maturation, temporal and prefrontal region presented great rest CBF increase across the first year of life. Moreover, we highlighted a late and remarkably synchronous maturation of the prefrontal and posterior superior temporal cortices. These different patterns of regional cortical rest CBF modifications reflect a timetable of local functional brain maturation and are consistent with baby’s cognitive development within the first year of life.

There are substantial changes in executive functioning during adolescence that may correspond with the onset and progression of puberty. The current study examines associations between pubertal development (timing and tempo) and changes in specific executive functioning skills (i.e., attention and self-control) across the transition from childhood to adolescence (ages 9.5–15.5) using data from the Study of Early Child Care and Youth Development (1099 youth; 52% female, 81% White, 83% above the poverty line). The findings indicated that early maturation was associated with faster increases in attention skills over adolescence for both boys and girls. Further, early maturation predicted worse self-control among girls but not boys. This study provides new insights on executive functioning during the transition to adolescence—a period of both vulnerability and opportunity.

Background. Malaria during pregnancy may threaten the mother’s health and cause serious structural damage to the internal architecture of the placenta, which subsequently affects the pregnancy outcome. A better understanding of the impact of malaria parasites on the placenta morphology is crucial for better management of pregnant women and their babies.Aim. To assess by stereology the histomorphology of selected placental structures in placenta malaria compared with normal placentae at term.Method. A total of 10 placentae comprising 5 controls and 5 cases were selected from 50 placentae that were collected at term (38 weeks ± 2 weeks) from the maternal delivery suit of Korle-Bu Teaching Hospital in Accra, Ghana. Blood from the placentae was collected for both rapid diagnostic test and microscopic examinations. Samples collected were examined forPlasmodiumparasites, after which they were classified as study group (Plasmodiumpositive) or control (Plasmodiumnegative). Stereological quantification using systematic uniform random sampling technique with test point and intersection counting of photomicrographs were employed to estimate the mean volume densities of syncytial knots, syncytial necrosis, foetal capillaries, and intervillous spaces of the placentae on a total of 1,600 photomicrographs.Results. Out of the fifty placental samples from the maternal side tested forPlasmodium,six representing 12% were found to be infected with the parasite by both rapid diagnostic test and microscopy. On stereological assessment, the mean volume density of syncytial knots was significantly higher in the placental malaria group compared with the control placentae at term (P = 0.0080), but foetal capillaries (P = 0.7813), intervillous spaces (P = 0.8078), and syncytial necrosis (P = 0.8249) were not significantly different.Conclusion. This preliminary result indicates that placental malaria may cause significant increase in the syncytial knots but not foetal capillaries, intervillous spaces, or syncytial necrosis. This finding signifies early maturation of the placenta and may be crucial in understanding perinatal outcomes.

Using a meta-analytic approach, this investigation examines the association between early pubertal timing and externalizing behaviors in adolescence and early adulthood. The findings showed that the effect size of early pubertal maturation on externalizing behaviors was r = 0.180. This small, yet significant effect size is consistent with the models of early pubertal maturation in that early maturation is associated with higher levels of externalizing behaviors. Using contrast analyses, we examined three potential moderators of this association: sex, the concurrent versus long-term effect of early puberty, and types of puberty assessments. Neither sex nor type of pubertal timing assessment moderated the effect significantly. However, results indicated that the effect was stronger for studies that measured pubertal timing and externalizing behaviors concurrently rather than longitudinally (i.e., examining prospective effect of pubertal timing on later externalizing behaviors). The findings are discussed in terms of implications for future research.

Structured AbstractObjectives Studies have shown that the mandibular permanent first molar (M1inf) in young children with isolated cleft palate is characterized by delay in maturation and has reduced crown width. Consequently, it is of interest to investigate the early maturation and width of the follicle and crown of M1inf in children with combined cleft lip and palate. Design Retrospective, longitudinal study. Cephalometric X-rays of 47 consecutive Danish children with UCCLP (37 males; 10 females) and 44 with unilateral incomplete cleft lip (UICL) (29 males; 15 females) examined at 2 and 22 months of age. UICL served as control group. Maturation (according to Haavikko), width of follicle (FW) and crown (CW) of M1inf were assessed. Results The maturation of the first mandibular molar was delayed in both genders at 2 and 22 months of age. FW and CW were smaller in children with UCCLP at both 2 and 22 months of age. There was a positive correlation between maturation and FW. Conclusions Maturation of the first mandibular molar is delayed in both genders, and FW and CW were reduced in UCCLP compared to controls. Maturation was correlated with FW.

The reaction norm between growth rate, age and size at maturity in ectotherms is widely debated in ecological literature. It has been proposed that the effect depends on whether growth is affected by food quality or temperature (called the Berrigan-Charnov puzzle). The present experiment tested this for Atlantic salmon (Salmo salar). We enhanced growth rates by increasing temperature and ratio of lipids to proteins in the food for groups of Atlantic salmon. Both treatments gave higher percentages of early mature and therefore smaller adults in contrast to the proposed Berrigan-Charnov puzzle. There was a difference between sexes in that males could attain maturity 1 year younger than females when reared under similar environmental conditions. Males that matured during the first year in sea water were smaller than similar aged immature males. The probability of that Atlantic salmon attained maturity for the first time during their second year in sea increased with growth rate during the preceding winter and if fed a high-lipid diet. Increased summer temperature exhibited no additional effect. Similar aged fish reared at elevated temperature and fed high-lipid diet attained maturity at a larger body mass and exhibited higher mass-length-ratios than those reared at natural temperature and fed a low-lipid diet, indicating that structural growth has priority over lipid deposits. Increased growth rate before the onset of maturation, whether this is owing to enhanced lipid content in food or increased water temperature, decreased age and therefore size at maturity. Enhanced lipid relative to protein content in food, but not temperature, had an additive positive effect on early maturation probability, likely due to increased amounts of reserve energy. These results may be general for ectotherm organisms.

Optimal life histories in a fluctuating environment are likely to differ from those that are optimal in a constant environment, but we have little understanding of the consequences of bounded fluctuations versus episodic massive mortality events. Catastrophic disturbances, such as floods, droughts, landslides and fires, substantially alter the population dynamics of affected populations, but little has been done to investigate how catastrophes may act as a selective agent for life-history traits. We use an individual-based model of population dynamics of the stream-dwelling salmonid marble trout (Salmo marmoratus) to investigate how trade-offs between the growth and mortality of individuals and density-dependent body growth can lead to the maintenance of a wide or narrow range of individual variation in body growth rates in environments that are constant (i.e., only demographic stochasticity), variable (i.e., environmental stochasticity), or variable with catastrophic events that cause massive mortalities (e.g., flash floods). We find that occasional episodes of massive mortality can substantially reduce persistent variability in individual growth rates. Lowering the population density reduces density dependence and allows for higher fitness of more opportunistic strategies (rapid growth and early maturation) during the recovery period.

Neural plasticity of pitch processing mechanisms at the human brainstem, as reflected by the scalp-recorded frequency-following response (FFR) to voice pitch, has been reported for normal-hearing adults. Characteristics and maturation of such a response during the first year of life have remained unclear. The purpose of this study was to examine the characteristics of FFR to voice pitch in normal-hearing infants and to make a direct comparison with adults using the same stimulus and recording parameters. 9 infants and 9 adults were recruited. A Chinese monosyllable that mimics the English vowel /i/ with a rising pitch was used to elicit the FFR to voice pitch. The results demonstrated that infant FFRs showed slightly larger Pitch Strength but comparable Frequency Error, Slope Error, and Tracking Accuracy to those obtained from adults. Early maturation of FFRs was also observed in the infants starting from 1 to 3 mo. of age.

To identify quantitative trait loci (QTL) influencing early maturation (EM) in rainbow trout (Oncorhynchus mykiss), a genome scan was performed using 100 microsatellite loci across 29 linkage groups. Six inter-strain paternal half-sib families using three inter-strain F1 brothers (approximately 50 progeny in each family) derived from two strains that differ in the propensity for EM were used in the study. Alleles derived from both parental sources were observed to contribute to the expression of EM in the progeny of the brothers. Four genome-wide significant QTL regions (i.e., RT-8, -17, -24, and -30) were observed. EM QTL detected on RT-8 and -24 demonstrated significant and suggestive QTL effects in both male and female progeny. Furthermore, within both male and female full-sib groupings, QTL on RT-8 and -24 were detected in two or more of the five parents used. Significant genome-wide and several strong chromosome-wide QTL for EM localized to different regions in males and females, suggesting some sex-specific control. Namely, QTL detected on RT-13, -15, -21, and -30 were associated with EM only in females, and those on RT-3, -17, and -19 were associated with EM only in males. Within the QTL regions identified, a comparison of syntenic EST markers from the rainbow trout linkage map with the zebrafish (Danio rerio) genome identified several putative candidate genes that may influence EM. Electronic supplementary material The online version of this article (doi:10.1007/s10126-008-9098-5) contains supplementary material, which is available to authorized users.

Reproductive allocation at one age is predicted to reduce the probability of surviving to the next year or to lead to a decrease in future reproduction. This prediction assumes that reproduction involves fitness costs. However, few empirical studies have assessed whether such costs may vary with the age at primiparity or might be overridden by heterogeneities in individual quality. We used data from 35 years' monitoring of individually marked semi-domestic reindeer females to investigate fitness costs of reproduction. Using multi-state statistical models, we compared age-specific survival and reproduction among four reproductive states (never reproduced, experienced non-breeders, reproduced but did not wean offspring, and reproduced and weaned offspring) and among contrasted age at primiparity. We assessed whether reproductive costs occurred, resulting in a trade-off between current reproduction and future reproduction or survival, and whether early maturation was costly or rather reflected differences in individual quality of survival and reproduction capabilities. We did not find any evidence for fitness costs of reproduction in female reindeer. We found no cost of gestation and lactation in terms of future reproduction and survival. Conversely, successful breeders had higher survival and subsequent reproductive success than experienced non-breeders and unsuccessful breeders, independently of the age at primiparity. Moreover, it was beneficial to mature earlier, especially for females that successfully weaned their first offspring. Successful females at early primiparity remained successful throughout their life, clearly supporting the existence of marked among-female differences in quality. The weaning success peaked for multiparous females and was lower for first-time breeders, indicating a positive effect of experience on reproductive performance. Our findings emphasize an overwhelming importance of individual quality and experience to account for observed variation in survival and reproductive patterns of female reindeer that override trade-offs between current reproduction and future performance, at least in the absence of harsh winters.

Objective To examine the relationship between pubertal timing and physical activity. Study design A longitudinal sample of 143 adolescent girls was assessed at ages 11 and 13 years. Girls' pubertal development was assessed at age 11 with blood estradiol levels, Tanner breast staging criteria, and parental report of pubertal development. Girls were classified as early maturers (n = 41) or later maturers (n = 102) on the basis of their scores on the 3 pubertal development measures. Dependent variables measured at age 13 were average minutes/day of moderate to vigorous and vigorous physical activity as measured by the ActiGraph accelerometer. Results Early-maturing girls had significantly lower self-reported physical activity and accumulated fewer minutes of moderate to vigorous and vigorous physical activity and accelerometer counts per day at age 13 than later maturing girls. These effects were independent of differences in percentage body fat and self-reported physical activity at age 11. Conclusion Girls experiencing early pubertal maturation at age 11 reported lower subsequent physical activity at age 13 than their later maturing peers. Pubertal maturation, in particular early maturation relative to peers, may lead to declines in physical activity among adolescent girls.

Superficial white matter (SWM) lies immediately beneath cortical gray matter and consists primarily of short association fibers. The characteristics of SWM and its development and aging were seldom examined in the literature and warrant further investigation. Magnetization transfer imaging is sensitive to myelin changes in the white matter. Using an innovative multimodal imaging analysis approach, vertex-based surface statistics (VBSS), the current study vertexwise mapped age-related changes of magnetization transfer ratio (MTR) in SWM from young adulthood to old age (30-85 years, N = 66). Results demonstrated regionally selective and temporally heterochronologic changes of SWM MTR with age, including (1) inverted U-shaped trajectories of SWM MTR in the rostral middle frontal, medial temporal, and temporoparietal regions, suggesting continuing myelination and protracted maturation till age 40-50 years and accelerating demyelination at age 60 and beyond, (2) linear decline of SWM MTR in the middle and superior temporal, and pericalcarine areas, indicating early maturation and less acceleration in age-related degeneration, and (3) no significant changes of SWM MTR in the primary motor, somatosensory and auditory regions, suggesting resistance to age-related deterioration. We did not observe similar patterns of changes in cortical thickness in our sample, suggesting the observed SWM MTR changes are not due to cortical atrophy. Hum Brain Mapp 37:1759-1769, 2016. © 2016 Wiley Periodicals, Inc.

Numerous diseases have been linked to genetic mutations that lead to reduced amounts or disorganization of arterial elastic fibres. Previous work has shown that mice with reduced amounts of elastin (Eln+/−) are able to live a normal lifespan through cardiovascular adaptations, including changes in haemodynamic stresses, arterial geometry and arterial wall mechanics. It is not known if the timeline and presence of these adaptations are consistent in other mouse models of elastic fibre disease, such as those caused by the absence of fibulin-5 expression (Fbln5−/−). AdultFbln5−/−mice have disorganized elastic fibres, decreased arterial compliance and high blood pressure. We examined mechanical behaviour of the aorta inFbln5−/−mice through early maturation when the elastic fibres are being assembled. We found that the physiologic circumferential stretch, stress and modulus ofFbln5−/−aorta are maintained near wild-type levels. Constitutive modelling suggests that elastin contributions to the total stress are decreased, whereas collagen contributions are increased. Understanding how collagen fibre structure and mechanics compensate for defective elastic fibres to meet the mechanical requirements of the maturing aorta may help to better understand arterial remodelling in human elastinopathies.

Effects of early physical maturation and accelerated pubertal changes on symptoms of major depression were examined in 639 African American children. Three rival hypotheses, early timing, off-time, and stressful change, were tested using 2 waves of data (mean ages = 11 and 13 years). The pubertal effect operates differently according to children's gender and age. For girls, early maturation was consistently associated with elevated levels of depressive symptoms. For boys, early maturers manifested elevated levels of depression only at age 11, but these symptoms subsided by age 13. Boys who experienced accelerated pubertal growth over time displayed elevated symptom levels. Results support the early timing hypothesis for girls and the stressful change hypothesis for boys. Time at assessment is critical when examining boys' pubertal transition.

This research explored sex differences in the pathways linking pubertal timing to depression across 4 years. A sample of 167 youth (M age = 12.41 years, SD = 1.19) and their caregivers completed measures of puberty and semistructured interviews of interpersonal stress and youth depression. Youth reported on psychological (negative self-focus, anxious arousal) and social–behavioral (coping) characteristics; parents reported on youths’ social–behavioral characteristics (withdrawal/social problems) and deviant peer affiliations. Early maturation predicted stable high trajectories of depression in girls; although early maturing boys showed low initial levels of depression, they did not differ from girls by the final wave of the study. Latent growth curve analyses identified several psychological, social–behavioral, and interpersonal pathways accounting for the contribution of pubertal timing to initial and enduring risk for depression in girls as well as emerging risk for depression in boys. These findings provide novel insight into multilevel processes accounting for sex differences in depression across the adolescent transition.

The amount of non-maternal care (allocare) found in primates varies greatly from species to species. Our paper examines this variation and focuses on possible reasons why mothers in some anthropoid primate species are prepared to relinquish their infants to other carers whereas others are not. We use data collected from the literature to test a number of hypotheses that attempt to explain the observed variation in non-maternal care. Analyses were carried out using comparative methods that control for the influence of both body size and phylogeny on life-history and ecological variation. The results support previous studies of both primates and other mammals in finding a clear link between the amount of allocare provided and female reproductive rates. Species with high allocare levels grow rapidly post-natally and wean their infants at a younger age (but at the same relative size) than species of the same body size with lower allocare levels. This early weaning allows high allocare species to support higher birth rates than low allocare species but does not result in earlier maturation. Our results, therefore, suggest that mothers allow non-maternal care of their infants in order to increase their own reproductive output. It is not clear whether such a strategy also benefits the infant, as we could find no link between the presence of allocare and early maturation (which would increase the infant’s reproductive output) or between allocare levels and infant survival (as measured by vulnerability to infanticide). This suggests that mothers and infants might come into conflict over transfer to other carers, as the benefits to the mother may not be accompanied by benefits to the infant. However, although mothers may benefit from allocare in some circumstances, they will not be expected to allow allocare if the costs are high (e.g. if there is a high risk to the infant).

Development of problem behaviour in early adolescence was predicted from change in pubertal stage and timing of pubertal development. Parent-reported (Child Behavior Checklist) and self-reported (Youth Self-Report) problem behaviour, pubertal stage and life events were assessed twice from a community sample of nearly 1300 Dutch children, aged 10-12 years at T1 and 12-14 years at T2. Pubertal change was a significant predictor of development in most parent-reported problems. Once initial differences in problems had been accounted for, the slower the progress in pubertal development, the higher the problem score at T2. Development of self-reported problems was independent of pubertal change. Pubertal timing predicted development of two parent-reported and three self-reported problem scales. Of the parent-reported problems, early maturation was associated with a decrease in boys' social problems and attention problems. Late maturing increased girls' social problems. Of the self-reported problems, early maturation was associated with an increase in girls' withdrawn and delinquent behaviour. Late maturing increased boys' attention problems. We conclude that pubertal development has small but significant effects on the development of problem behaviour in early adolescence.

Objective Early detection of autism is critical for effective intervention, but currently, no simple screening tests are available. Furthermore, little is known about the development of brain dynamics in young children. We examine the early neurophysiological manifestations of autism by retrospectively analyzing EEG. In particular, we focus on maturation of the posterior basic rhythm (PBR), which is one of the most characteristic features of the normal EEG, and comprises a discrete functional state. Methods Subjects with a diagnosis of autism ( n =74), as well as normal ( n =134) and epileptic ( n =108) controls, were extracted retrospectively from our digital EEG database. Segments with clear PBR were extracted, and standard signal analysis methods were used to calculate peak PBR frequency, power, and coherence. Results In our cohort, a subset of autistic children show accelerated development of the PBR, with early maturation especially in the 2- to 4-year old range. The overall coherence of PBR-specific activity is also lower in autistic children in our cohort. Conclusions These findings provide evidence that autism is associated with accelerated development of the PBR. Significance These findings generate a clinical hypothesis for future prospective studies on the efficacy of these simple measures as a diagnostic or screening tool.

Barnacles, which are sedentary marine crustaceans, have diverse sexual systems that include simultaneous hermaphroditism, androdioecy (coexistence of hermaphrodites and males) and dioecy (females and males). In dioecious and androdioecious species, the males are very small and are thus called dwarf males. These sexual systems are defined by two factors: sex allocation of non-dwarf individuals and the presence or absence of dwarf males. We constructed an ESS model treating sex allocation and life history simultaneously to explain sexual systems in barnacles. We analyzed the evolutionarily stable size-dependent resource allocation strategy to male reproductive function, female reproductive function and growth in non-dwarf barnacles, and the ESS proportion of dwarf males, under conditions of varying mortality and food availability. Sex allocation in non-dwarf individuals (hermaphrodites or females) is affected by mate availability and the proportion of dwarf males. When hermaphrodites appear, all hermaphrodites become protandric simultaneous hermaphrodites. Furthermore, high mortality and poor resource availability favor dwarf males because of their early maturation and weakened sperm competition. In conclusion, we showed that combining sex allocation and life history theories is a useful way to understand various sexual systems in barnacles and perhaps in other organisms as well.

Heavy metal cadmium (Cd) traces are able to promote growth (growth promoter) and induce early maturation in Oreochromis mossambicus fries of both sexes, whereas, in the adults, they degenerate the gonads and their function. The gathered data on length-weight relation, gonado-somatic index, hepato-somatic index, egg numbers and reproductive hormones such as gonadotropins (GtH-I and GtH-II) and gonadial hormones such as progesterone, testosterone and estradiol levels all prove Cd as an endocrine disruptor.

Background Early maturation in the Atlantic salmon is an interesting subject for numerous research lines. Prior to sea migration, parr can reach sexual maturation and successfully fertilize adult female eggs during the reproductive season. These individuals are known as precocious parr, mature parr or "sneakers". Reasons for early maturation are unknown and this transitory stage is usually considered to be a threshold trait. Here, we compare methylation patterns between mature and immature salmon parr from two different rivers in order to infer if such methylation differences may be related to their maturation condition. First we analyzed genetic differences between rivers by means of AFLPs. Then, we compared the DNA methylation differences between mature and immature parrs, using a Methylation-Sensitive Amplified Polymorphism (MSAP), which is a modification of the AFLPs method by making use of the differential sensitivity of a pair of restriction enzymes isoschizomeres to cytosine methylation. The tissues essayed included brain, liver and gonads. Results AFLPs statistical analysis showed that there was no significant differentiation between rivers or a significant differentiation between maturation states in each river. MSAP statistical analysis showed that among the three tissues sampled, the gonads had the highest number of significant single-locus variation among populations with 74 loci followed by brain with 70 and finally liver with only 12. Principal components analysis (PCA) of the MSAP profiles revealed different profiles among different tissues (liver, brain and testis) clearly separating maturation states in the testis tissue when compared to the liver. Conclusions Our results reveal that genetically-similar mature and immature salmon parr present high levels of DNA methylation variation in two of the three analyzed tissues. We hypothesize that early maturation may be mostly mediated by epigenetic processes rather than by genetic differences between parrs. To our knowledge this is the first study that attempt to link phenotypic plasticity in salmonids and epigenetic changes.

The onset of downstream migration of European eels is accompanied by a cessation of feeding and the start of sexual maturation which stresses the link between metabolism and sexual maturation, also suggesting an important role for exercise. Exercise has been tested with eels in swim tunnels and was found to stimulate the onset of sexual maturation. In this study, we have investigated the interplay between migration and maturation in the field during the downstream migration of female silver eels. Temporal changes in migratory status and sexual maturation among silver eels of the upstream Rhine River system over 3 months of the migration season (August, September and October) were determined in biometrical parameters, plasma 17ß-estradiol and calcium levels, oocyte histology and gonadal fat levels. Furthermore, the ecological relevant parameters age as determined by otolithometry and health aspects indicated by haematocrit, haemoglobin and swim-bladder parasite load were measured. Silver eels were estimated to be 14 years old. A strong temporal progression in migratory stage was shown over the months of downstream migration. Catches probably represented a mix of reproductive migrants and feeding migrants of which the ratio increased over time. Furthermore, this study confirmed our hypothesis linking the migratory stage to early maturation as indicated by enlargement of the eyes, oocyte growth and fat deposition in the oocytes, exactly the same changes as found induced by exercise but not ruling out environmental influences. Migrants show extensive fat uptake by the oocytes, probably stimulated by the swimming exercise. In addition, at least 83% of the silver eels in this spawning run may have suffered from negative effects of swim-bladder parasites on their swimming performance.

The California National Primate Research Center (CNPRC) houses more than 1,000 rhesus macaques (Macaca mulatta) of mixed Chinese–Indian ancestry. Most of these animals are kept in outdoor field cages, the colony's long term breeding resource. Since 2001, hybrids comprised between 4 and 49% of the field cage populations, but in most cases have represented a maximum of 10% of those populations. The increasing prevalence of hybrids is partly due to management efforts to distribute genetic diversity effectively and minimize genetic subdivisions. However, other factors may also contribute to the spread of hybrids within the colony, most notably variance in socio-sexual behaviors and physical attributes. It is known that hybrids of some species exhibit heterosis, such as early maturation, that can enhance reproductive success, and anecdotal observations of mixed groups of hybrid, Indian and Chinese animals at the CNPRC suggest that hybrids are more sexually active. To determine whether hybrids experienced a reproductive advantage, a study was conducted using birth records of 5,611 offspring born in the CNPRC colony between 2003 and 2009. We found that while the degree of Chinese ancestry (DCA) appeared to influence the maturational schedule of both males and females (maturation was inversely related to proportion of Chinese ancestry), DCA had no independent effect on either male or female RS or rank. Therefore, we have found no evidence that a hybrid phenotype confers an absolute reproductive advantage in our colony. Am. J. Primatol. 73:671–678, 2011. © 2011 Wiley-Liss, Inc.

Objective To examine changes in insulin sensitivity (SI), compensatory acute insulin response (AIR), and β-cell function/disposition index (DI) across puberty in overweight Latino boys and girls. Study design Latino children (n = 253) were followed annually for up to 5 years. Longitudinal modeling was used to examine changes in SI, AIR, DI, and fasting and 2-hour glucose and insulin across Tanner stage. Results In boys, SI decreased in early puberty with a recovery by late puberty. The compensatory increase in AIR was appropriate in early maturation, but after Tanner stage 3, AIR declined by more than that predicted from the recovery in SI. For girls, SI decreased in early puberty and across all stages of maturation. In early maturation, there was an appropriate compensatory increase in AIR, but after Tanner stage 3, AIR decreased. Thus, DI deteriorated across puberty in boys and girls. Conclusions In overweight Hispanic youth, compensatory changes in insulin secretion fails after Tanner stage 3 in both sexes, indicating β-cell deterioration during this critical period of development, thus increasing risk for type 2 diabetes.

Degradation of enamel matrix proteins, and their removal during early maturation, is critical for the growth of large enamel crystals in the subsequent processes of enamel maturation. In this study, we sought to demonstrate, using in vivo zymography, the exact sites of proteolysis in maturing enamel and its relationship to the overlying ameloblasts. The maturing enamel surfaces of rat and bovine incisors were exposed and painted either with pre-exposed autoradiographic emulsion or with densely fluorescein-conjugated (DQ) gelatin. After a few hours, photographic development of the emulsion revealed alternate black and white banding patterns over the maturing enamel surface. DQ gelatin also revealed similar banding patterns of fluorescent and non-fluorescent regions. White, powdery areas of emulsion and fluorescent bands of DQ gelatin both corresponded to the areas of ruffle-ended ameloblasts, at least up to the mid stages of enamel maturation, implicating a predominant contribution of ruffle-ended ameloblasts in the degradation of enamel matrix proteins. Powdery white bands in autoradiographic emulsion shifted from the areas of ruffle-ended to smooth-ended ameloblasts in late maturation in both bovine and rat incisors and were not influenced by proteinase inhibitors or heat inactivation, implicating non-enzymatic interactions. DQ gelatin, in fact, did not generate any fluorescence in such smooth-ended ameloblast regions.

Sex differences in math/spatial performance demand explanations. Within the biological view, the complexity and number of variables make the explanation difficult at best. Laterality and age of pubertal onset have been investigated prominently in this context but rarely considered as interactions in the same study. Some 468 college subjects with SAT MATH (SAT M) scores were divided into 12 groups defined by sex, laterality, and age (early, middle, and late) of pubertal onset. Significant main effects for sex and age of onset emerged, as did an interaction between lateral preference and pubertal onset. Generally males outperformed females. The combination of maleness, sinistrality, and early maturation was associated with high SAT M scores. Sinistrality and late maturation among females predicted very poor math performance.

Peak velocity, duration and accuracy of eye movements (saccade, vergence and combined saccade-vergence eye movements) were investigated in fourteen normal children (4.5 to 12 years of age) and ten normal adults (22 to 44 years of age). Horizontal movements from both eyes were recorded simultaneously by the oculometer, a photoelectric device. Peak velocity of all eye movements, saccades, and vergence (convergence and divergence), attains adult levels by the age of 4.5 years and there is no significant change over the age range studied (4.5 to 44 years). Vergence duration is longer only in young children (below 8 years of age). The reciprocal interaction between saccade and vergence during combined movements known in adults, i.e. acceleration of the vergence by the saccade (increase of velocity and decrease of duration) and deceleration of the saccade by the vergence (decrease of velocity and increase of duration) was found to be similar in children. The accuracy of eye movements is good on average for both saccades and vergence by the age of 4.5 years, and does not change with age; an exception is the variability of saccade amplitude, which is higher in children less than 8 years old. Taken together, the results indicate early maturation of brainstem structures controlling spatio-temporal aspects of saccades, vergence and their interaction.

Our objectives were to compare: (1) conception rates (in early postpartum Japanese Black beef cows) to timed-artificial insemination (timed-AI) among Ovsynch and Ovsynch plus CIDR protocols, and a protocol that used estradiol benzoate (EB) in lieu of the first GnRH of the Ovsynch plus CIDR; and (2) the effects of these protocols on blood concentrations of ovarian steroids. Cows in the control group (Ovsynch; n=35) underwent a standard Ovsynch protocol (GnRH analogue on Day 0, PGF(2 alpha) analogue on Day 7 and GnRH analogue on Day 9), with timed-AI on Day 10, approximately 20 h after the second GnRH treatment. Cows in the Ovsynch+CIDR group (n=31) received a standard Ovsynch protocol plus a CIDR for 7 days (starting on Day 0). Cows in the third treatment group (EB+CIDR+GnRH; n=41) received 2mg of EB on Day 0 in lieu of the first GnRH treatment, followed by the same treatment as in the Ovsynch+CIDR protocol. The conception rate tended to be greater in the Ovsynch+CIDR group (67.7%, P

Contrasting theories posit the source of verbal repetition priming in the activation of preexisting memory representations in the input lexicons or, alternatively, in the formation of new episodic memory traces. The two hypotheses predict different outcomes from the comparison of developmental rates of visual and auditory verbal repetition priming. The activation theory predicts a developmental dissociation between the early maturation of auditory priming and the later maturation of visuo-verbal priming, contingent upon the discrepant acquisition rates of the auditory and visual input lexicons. The episodic theory, instead, does not make such an assumption. We administered visual and auditory implicit Stem Completion to 40 reading beginners (first-graders), 40 third-graders and 20 fifth-graders. Consistent with previous reports, auditory priming was stable across different age groups. Visual priming and a measure of lexicality in reading, instead, showed a parallel developmental increase passing from reading beginners to third-graders and to fifth-graders. In the overall group, visual priming and the measure of lexicality in reading were significantly associated. These data describe a new developmental dissociation in the memory abilities of normal children and provide further support for the hypothesis that repetition priming for words reflects facilitated access to previously established memory representations.

Children underwent motor and sensory testing during each of 3 consecutive years beginning at kindergarten entrance. Children were assigned to either a motor-normal or motor-delayed group based on results from testing during the 1st year of the study. Motor-normal subjects (n = 17) had standard scores on a global motor-sensory test that fell within one standard deviation of the mean. Motor-delayed subjects (n = 12) had a global motor-sensory test standard score indicating greater than one standard deviation of motor delay and, in addition, were delayed by a minimum of one standard deviation on four of five of the motor-sensory test subtests. At the conclusion of the 3-year study, the mean standard score of the motor-delayed group remained greater than one standard deviation below the performance of the motor-normal group as measured by the global motor-sensory test. Statistical analysis using repeated measures analysis of variance indicated that the motor-delayed group made gains but did not close the gap between themselves and the motor-normal group during the 3-year study. Group x time interaction effects showed that during the study, significant gain was made by the motor-delayed group on the motor coordination subtest of the motor-sensory test. The study supports the conclusion that motor-delayed children without early intervention fail to outgrow their motor delays by age 8 years. (J Child Neurol 1993;8:323-329).

Yearling heifer growth data were obtained during 4 yr for 524 heifers allotted to either humid bermudagrass pastures (Overton) or semiarid rangeland (Uvalde). Each year, heifers were allotted on April 15 to four forage availability levels (400 to 2,800 kg of DM per 100 kg of BW at Uvalde and 80 to 260 kg of DM per 100 kg of BW at Overton) maintained by varying the stocking rate monthly until mid-October of each year. Forage availability and yearling heifer characteristics (weight, condition score, and height at hooks, taken on April 15) were treated as continuous variables in regression analyses. Final heifer weight, height, and condition responses to in- creased forage allowance were related to yearling phenotypes differently for the two locations. Gen- erally, at Overton, forage availability influenced final characteristics to a greater extent than did yearling variables, whereas the trend was the opposite at Uvalde. At Uvalde, the yearling char- acteristic that had the largest effect on perform- ance was height at hooks. Yearlings with large frames benefited from increased forage allowance by accumulating body fat at a faster rate than those with small frames. In contrast, at Overton, the yearling characteristic that had the largest effect on performance was condition. Fat heifers responded to increased forage availability to gain even greater advantages in fatness at the expense of potential growth in height and, thus, achieved early maturation. Yearling phenotypes were more broadly adapted to arrays of forage availability for humid, improved pastures than for semiarid rangeland.

While the association of young maternal age with low birthweight (LBW) is well known, the contribution of early menarche to this association has never been studied. We examined the effects of early menarche (less than or equal to 11 years) on LBW and its two major underlying causes: pre-term delivery and smallness-for-gestational-age (SGA). Results represent a narrow chronological age range, 17-18 years, of a larger geographically based cohort of 2789 pregnant adolescents. Adjusted odds ratios (AOR) indicated that early menarche was significantly associated with an increased risk of LBW which was specific to SGA. The attributable risk of SGA with early menarche exceeded 20%. Early age at menarche is also correlated with an earlier onset of sexual activity, pregnancy, and childbearing. Consequently, adolescents with early menarche are over-represented in a sample limited to young gravidae or a sample that contains a stratum of young gravidae. This may have previously obscured the effects or early menarche on foetal growth and attributed them to a more frequently measured characteristic, young maternal age. Thus, effects of secular change in age at menarche may not be wholly benign. Improvements in maternal fertility and nutritional status appear to be offset by intrauterine growth retardation in the offspring.

SUMMARY A 5-year-old girl with the McCune-Albright syndrome presented with precocious puberty secondary to autonomously functioning ovarian cysts, followed by true central puberty. Progression from gonadotrophin-independent to gonadotrophin-dependent precocious puberty may occur from elevated sex steroid levels leading to the early maturation of the hypothalamic-pituitary axis.

Binding of serotonin to rat brain membranes increased linearly from birth to adulthood, but newborn receptor densities were already 39% of adult levels. These data suggest a postnatal development of serotonin receptors, coincident with synaptic maturation but do not preclude a non-transmitter function for serotonin during early maturation.

Isometric tension was measured in arterial strips from neonatal lambs and adult sheep, after stimulation by angiotensin II. During the early maturation period immediately following birth (3 weeks) there was a progressive increase in sensitivity to the agent.

• In a complementary clinical and biochemical study of patients with globoid leukodystrophy (GLD), cases differed from the classic phenotype of Krabbe disease and suggested a broader spectrum of clinical presentations. In terms of pathogenesis, the advanced development achieved before symptom onset suggested normal early maturation and myelination. Enzyme studies were carried out on white blood cells from the patients, their siblings, parents, and normal agematched controls. These studies utilized galactosyl ceramide of brain origin and a new assay technique. We found a specific deficit in cerebrosidase activity in leukocyte preparations from patients with GLD and intermediate levels of activity in their parents. These findings confirm prior reports and indicate an autosomal recessive mode of genetic expression.

• As shown In 11,464 black and white pregnant teenagers and 28,477 older pregnant women, teenage mothers tend to be of small stature and weight, consistent with age and early maturation. The small size of their infants is in proportion to their smaller size and not to their early age at conception. Although the progeny of teenage mothers show a higher incidence of prematurity and diminished birth size, in the extent of fetal loss, low Apgar and Bayley scores, and In the frequency of medical abnormalities, they are not at a disadvantage compared with infants of third-decade mothers of comparable size. ( Am J Dis Child 1983;137:365-368)

Eight-week-old Harco Sex-Link pullets were assigned to four growing regimens. Feed was restricted to Group 1. The birds reached an average weight of 1.52 kg at 20 weeks of age and were then light stimulated. Group 2 received the same ration ad lib and reached an average weight of 1.64 kg at 16 weeks. At this age they were light stimulated. Birds in Groups 3 and 4 were separated into two weight classes at 8 weeks of age. Those below the median weight received an 18% protein grower ration and those above the median weight a 16% ration. Group 3 birds were grown similarly to Group 1; Group 4 birds were grown similarly to Group 2. At housing, each group was equally divided and given either a 17 or 19% protein layer ration. Two cage designs (standard and reverse) were used and each treatment combination was equally represented. Ad lib-fed, early-housed pullets reached 1.64 kg at 16 weeks of age, but they did not come into production until 19.4 weeks of age. Hen-day percent production (HDP) was significantly less than for the late-housed pullets. Feed per dozen eggs was not affected by the early housing, but early-housed pullets laid significantly smaller eggs and feed per gram egg was significantly increased. Hens in reverse cages on a 19% protein layer ration laid the largest eggs in weight and size. Although early housing had a detrimental effect on average egg weight, it appeared possible to manipulate egg weight and size distribution through a combination of cage design and layer protein. Birds grouped by body weight at 8 weeks had higher uniformity, but this trait was not correlated with egg numbers or size. Moreover, housing body weights were not significantly correlated with egg size, suggesting factors other than body weight were responsible for the smaller eggs from early-housed pullets.

Three hundred and sixty 17-week-old Harco Sex Link pullets were transferred to laying cages and received 13 hr of light daily for the first week followed by 15 hr the second and subsequent weeks. A second group of 360 pullets remained in the growing facility on 8 hr of light until 19 weeks of age when the light was increased to 13 hr. At 20 weeks these birds were transferred to the laying facility where they received 15 hr of light daily for the duration of the experiment. A 15% protein grower ration was fed until daily production of each group reached 2%, at which time the diets were changed to either a 17 or 19% protein layer ration, each supplemented with DL-methionine so as to contain .3 or .4% total methionine. Early housed pullets averaged 140.4 days at first egg whereas late housed reached sexual maturity at 149 days. The initial increase in egg production by the early housed pullets was followed by a more rapid decline and overall, from housing to 66 weeks, equivalent egg numbers were produced. The early housed pullets were less efficient than the late housed birds due in part to their larger body mass. The greater percentage of small and medium-sized eggs produced by the early housed birds was not influenced by increasing the concentration of protein or methionine in the layer ration.