Evening activities as a potential confound in research on the adrenocortical system in children

The relation among children's evening activities, behavioral characteristics, and activity of the hypothalamic-pituitary-adrenocortical axis was assessed in normally developing children ages 7 to 10 years. Salivary cortisol at bedtime was compared on evenings when children had structured activities outside of the home with unstructured evenings at home in relation to parental reports of children's behavioral characteristics. Participating in evening activities, particularly sport activities, was associated with small increases in bedtime cortisol levels in boys but not in girls. Differences in cortisol on activity versus no-activity nights were negatively related to children's social isolation. These results show that in studies with children, nights on which participants engage in sport activities should be avoided when collecting ambulatory measures of salivary cortisol concentrations.     

Dampening of Adrenocortical Responses during Infancy: Normative Changes and Individual Differences

Changes in cortisol and behavioral responses were examined longitudinally in 83 infants (39 girls, 44 boys) tested at their well-baby exams with inoculations at 2, 4, 6, and 15 months (72 infants completed all testing). Another sample of 2-, 4-, and 6-month-olds ( n = 18 per age) received mock exams without inoculations to determine early developmental changes to the exam procedures. Behavioral distress was coded every 30 sec during the exam, a 5-min inoculation period, and a 20-min recovery period. Salivary cortisol was obtained upon arrival at the clinic and 25 min after the beginning of the inoculation period. To the exam-inoculation procedures, cortisol responses were high at 2 months, decreased significantly between 2 and 4 months, remained comparable between 4 and 6 months, and then declined again between 6 and 15 months. Between 6 and 15 months there was also a decrease in pretest cortisol. By 15 months, significant increases in cortisol from pre- to posttest were no longer observed for most infants. To the exam-only procedures, cortisol responses decreased between 2 and 4 months, and by 4 months most infants failed to show pre- to posttest increases in cortisol. Behavioral distress decreased between 2 and 6 months, but increased again at 15 months. While crying and cortisol were modestly correlated during the 2- to 6-month exam-inoculation procedures, at 15 months no significant correlations were obtained. Behavioral and hormonal reactions thus followed different ontogenetic paths and may provide different information about infant functioning. There was some evidence that the emergence of the circadian rhythm in cortisol might be related to the early decrease in cortisol response.     

Coping with aversive stimulation in the neonatal period: quiet sleep and plasma cortisol levels during recovery from circumcision

Measures of behavioral state and plasma cortisol were obtained on 80 healthy, full-term, 2-3-day-old, male newborns who were scheduled to be circumcised. To establish baseline or precircumcision levels, the newborns were observed, and behavioral state was recorded for the half hour prior to circumcision. Blood was sampled via heelstick for plasma cortisol determination at the end of this observation period. The newborns were then circumcised and assigned randomly to one of 4 postcircumcision, blood-sampling time-point groups. The time points were 30, 90, 120, and 240 min following the beginning of circumcision. Behavioral state was observed during circumcision and for the half hour prior to taking the second blood sample. The results showed a return to baseline cortisol levels sometime prior to 240 min, with data from an additional group of 10 newborns indicating that the return occurred by 150 min. Behavioral distress during circumcision was associated with elevations in plasma cortisol at 30 and 90 min. Quiet sleep was correlated negatively with plasma cortisol prior to circumcision, and significant increases in quiet sleep followed circumcision, with the greatest increase corresponding to the period of most rapid reductions in cortisol.     

Acute exercise-induced irisin release in healthy adults: Associations with training status and exercise mode

There is a growing interest in exploring irisin response to acute exercise; however, the associations of acute exercise-induced irisin release with training status and exercise mode are not fully understood. This study was primarily designed to evaluate these associations. Sixteen healthy adults (8 trained versus 8 untrained) underwent a bout of cycling at 80% of maximal oxygen uptake (VO_2max) for 50?min, with blood drawn pre-, 10-, and 180-min post-exercise. Another 17 healthy adults performed 2 bouts of graded exercise (cycling and running) until exhaustion on separate days using a randomized cross-over design, with blood taken pre-, 0-, 10-, and 60-min post-exercise. Circulating irisin, creatine kinase (CK), aspartate aminotransferase (AST), and myoglobin (Mb) were measured, and their respective areas under the curves (AUCs) were calculated. Irisin increased 10-min after 50?min of cycling at 80% of VO_2max, while its changes from baseline to post-exercise and the amount of exercise-induced irisin release (presented as AUC) were comparable between trained and untrained adults (all P?>?.05). Irisin remained elevated 10-min post-exhausting running but decreased towards baseline 10-min post-exhausting cycling. Exhausting running induced an increase in irisin release for the whole course of exercise and recovery periods, but cycling did not. Acute exercise-induced irisin changes seemed not related to changes of CK, aspartate AST, and Mb in general. In conclusion, acute exercise-induced irisin release is not associated with training status but might be affected by training mode. Future studies are required to investigate which exercise mode might be most efficient in altering irisin.     

Peer Problems Among Postinstitutionalized,Internationally Adopted Children: Relations to Hypocortisolism,Parenting Quality,and ADHD Symptoms

Seventy-eight postinstitutionalized (PI) children adopted at ages 17–36 months were assessed 2, 8, 16, and 24 months postadoption on measures of cortisol and parenting quality, and compared to same-aged children adopted from foster care (FC, n = 45) and nonadopted children (NA, n = 45). In kindergarten (M_age = 6.0 years), teachers, parents, and trained observers completed measures of peer relationships and attention deficit hyperactivity disorder (ADHD) symptoms. PI children had more peer problems and ADHD symptoms according to teachers and observers than NA children with FC children in between, whereas both PI and FC children were at significantly greater risk of hypocortisolism (i.e., blunted cortisol diurnal rhythm and reactivity). Hypocortisolism and ADHD symptoms mediated the association between preadoption adversity and peer difficulties. Higher postadoption parenting quality was protective.     

A Perspective on the Intended Science Curriculum in Iceland and its ‘Transformation’ over a Period of 50 Years

In recent decades, a consensus has emerged among educators and scientists that all compulsory school students need good science education. The debate about its purpose and nature as a school subject in an emerging information society has not been as conclusive. To further understand this, it helps to examine how the science curriculum has transformed and what forces have shaped it as a core curricular area over time. This article sheds light on the transformation of the science curriculum for compulsory schools in Iceland in force from 1960 to 2010. Using criteria based on curriculum ideologies regarding the function of learners, instructors and subject matter in the learning process and the orientation of content and product versus process and development, it offers findings from content analysis of the intended science curriculum. The official curriculum was studied and conceptualised as it has evolved over time. The curriculum developers appear to have been striving for a compromise between conflicting views, resulting in what the authors of this article conceive as a ‘kaleidoscopic quilt’ of ideas over the period studied.