Correction to: Investigation of brain structure in the 1-month infant.

The authors regret that, in this article, there was an error in the analyses comparing infant male and female regional brain volume differences.

Investigation of brain structure in the 1-month infant.

The developing brain undergoes systematic changes that occur at successive stages of maturation. Deviations from the typical neurodevelopmental trajectory are hypothesized to underlie many early childhood disorders; thus, characterizing the earliest patterns of normative brain development is essential. Recent neuroimaging research provides insight into brain structure during late childhood and adolescence; however, few studies have examined the infant brain, particularly in infants under 3 months of age. Using high-resolution structural MRI, we measured subcortical gray and white matter brain volumes in a cohort (N = 143) of 1-month infants and examined characteristics of these volumetric measures throughout this early period of neurodevelopment. We show that brain volumes undergo age-related changes during the first month of life, with the corresponding patterns of regional asymmetry and sexual dimorphism. Specifically, males have larger total brain volume and volumes differ by sex in regionally specific brain regions, after correcting for total brain volume. Consistent with findings from studies of later childhood and adolescence, subcortical regions appear more rightward asymmetric. Neither sex differences nor regional asymmetries changed with gestation-corrected age. Our results complement a growing body of work investigating the earliest neurobiological changes associated with development and suggest that asymmetry and sexual dimorphism are present at birth.

Mapping White Matter Microstructure in the One Month Human Brain.

White matter microstructure, essential for efficient and coordinated transmission of neural communications, undergoes pronounced development during the first years of life, while deviations to this neurodevelopmental trajectory likely result in alterations of brain connectivity relevant to behavior. Hence, systematic evaluation of white matter microstructure in the normative brain is critical for a neuroscientific approach to both typical and atypical early behavioral development. However, few studies have examined the infant brain in detail, particularly in infants under 3 months of age. Here, we utilize quantitative techniques of diffusion tensor imaging and neurite orientation dispersion and density imaging to investigate neonatal white matter microstructure in 104 infants. An optimized multiple b-value diffusion protocol was developed to allow for successful acquisition during non-sedated sleep. Associations between white matter microstructure measures and gestation corrected age, regional asymmetries, infant sex, as well as newborn growth measures were assessed. Results highlight changes of white matter microstructure during the earliest periods of development and demonstrate differential timing of developing regions and regional asymmetries. Our results contribute to a growing body of research investigating the neurobiological changes associated with neurodevelopment and suggest that characteristics of white matter microstructure are already underway in the weeks immediately following birth.

Occurrence of perfluoroalkyl sulfonates and carboxylates in German drinking water sources compared to other countries.

Different homologues of C4 to C8 perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFASs) were detected in German surface waters, bank filtrates, artificially recharged groundwaters, and drinking waters. If no point sources are located nearby, the typically measured levels are in the low ng/L range. In the presence of point sources, such as a fluorochemical production site, a leaching agricultural fertilizer contaminated with PFCAs and PFASs, or drained PFC containing fire-fighting foams, much higher concentrations in the microg/L range occur. This situation is similar in Germany and other countries.

Development of children's body knowledge, using knowledge of the lungs as an exemplar.

When teaching young children about health care procedures, health care professionals must assess what children already know about human anatomy and physiology, otherwise known as "body knowledge," to correct misconceptions and expand children's knowledge of their bodies. This article summarizes studies published between 1935 and 2000 that were related to the development and assessment of children's body knowledge, using knowledge of the lungs as an exemplar of body knowledge. Types of instruments used to measure body knowledge are described, and suggestions for future studies are provided.

2,3,7,8-tetrachlorodibenzo-p-dioxin increases serum and kidney retinoic acid levels and kidney retinol esterification in the rat.

Halogenatedorganic environmental contaminants such as dioxins are well-known to affect tissue levels of retinoids. To further investigate the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on retinoid homeostasis, adult male Sprague-Dawley rats were killed 1-112 days after a single oral dose of 10 microg TCDD/kg body wt. Additional groups of rats were killed three days after a single oral dose of 0.1, 1, 10, or 100 microg TCDD/kg body wt. Serum and renal retinoic acid levels were measured, as were levels of serum retinol-binding protein (RBP) in liver, kidneys, and serum. Hepatic and renal formation as well as hepatic hydrolysis of retinyl esters were determined, together with hepatic and renal retinoid levels. In addition, one of the retinyl ester hydrolase (REH) activities was investigated in isolated hepatocytes and hepatic stellate cells from rats killed 7 days after a single oral dose of 10 microg TCDD/kg body wt. No increased hepatic REH activity that could explain the decreased hepatic retinyl ester levels following TCDD treatment was found. In the liver, TCDD increased protein levels, but not mRNA levels, of RBP. A causal relationship is suggested for the increased renal lecithin:retinol acyltransferase (LRAT) activity and increased renal retinyl ester levels in TCDD-treated rats. Importantly, TCDD was shown to substantially increase serum and renal levels of retinoic acid. The ability of TCDD to cause increased tissue retinoic acid levels suggests that TCDD may alter the transcription of retinoic acid-responsive genes.

Homesickness in preadolescent and adolescent girls: risk factors, behavioral correlates, and sequelae.

Examined homesickness in 117 girls ages 8 to 16 during a 2-week stay at summer camp. (Homesickness is the distress or impairment caused by an actual or anticipated separation from home. It is characterized by acute longing and preoccupying thoughts of home and attachment objects.) Elevated preseparation levels of homesickness, high expectations of homesickness, negative separation attitudes, low decision control, and little previous separation experience predicted in-camp levels of homesickness. During the separation, homesickness was associated with insecure interpersonal attitudes, negative initial impressions of the novel environment, high perceived distance from home, and low perceived control. Female surrogate caregivers rated homesick girls as having lower social status and more somatic complaints, social problems, and externalizing behavior than less homesick girls. Although the prevalence, intensity, and longitudinal course of homesickness in girls did not differ from analogous samples of boys, girls' profile of risk factors, correlates, and sequelae is unique in its mixed behavioral presentation and small correlations with age and experience.

Streptomycin- and rifampin-resistant mutants of Escherichia coli perturb F exclusion of bacteriophage T7 by affecting synthesis of the F plasmid protein PifA.

Certain alleles of rpsL that confer resistance to the antibiotic streptomycin almost completely relieve F exclusion of bacteriophage T7. Introduction of a specific rpoB allele conferring resistance to rifampin into the rpsL strain restores the ability of the F-containing strain to exclude T7. This variation in the severity of F exclusion is reflected in the levels of the F-encoded inhibitor protein PifA: F'-containing cells that harbor specific rpsL alleles are phenotypically Pif-, but become Pif+ by the further acquisition of a specific rpoB allele. F-containing cells harboring the gyrA43(Ts) mutation also appear phenotypically Pif-, possibly because repression of the pif operon is enhanced by an altered DNA conformation in the gyrase mutant strain.

Test-retest reliability of a body knowledge instrument in school-age children.

The authors investigated the reliability of a body knowledge tool utilizing a test-retest design. Subjects were 86 children, 6-12 years old, who attended a rural elementary school in Southwestern Pennsylvania. Data consisted of children's perceptions of internal body parts as measured by responses to the Modified Gellert Body Knowledge Interview. A second set of body knowledge scores was generated when the children were retested 7 days after the original testing. A significant relationship (r = .70, p < .001) was found between the two body knowledge scores. Analysis of the body knowledge scores indicated that children's knowledge of the human body increases with age. A significant correlation was also found between grade level and body knowledge scores. Gender was unrelated to level of performance on the body knowledge instrument. The most commonly listed body parts were heart, brain, bones, veins, blood, and muscles. The reliability established for this instrument indicates that studies could be pursued to validate its effectiveness in determining school-age children's body knowledge.

Pre-operative preparation: effects on immediate pre-operative behavior, post-operative behavior and recovery in children having same-day surgery.

This study explored whether preoperative preparation affects the immediate preoperative behavior, post-operative behavior, and recovery in children undergoing same-day surgery. An experimental design was utilized. Three hypotheses were tested: that children who receive pre-operative preparation will (1) display fewer intra-operative and post-operative complications; (2) use lesser amounts and less frequent administration of pain medications post-operatively; and (3) exhibit fewer behavioral problems during pre-, intra-, and post-operative periods than children who do not receive such preparation. Sixty children, ages 2-10 years, were observed at a community hospital's same-day surgery facility, with subjects randomly selected. Subjects were directly observed during the pre-, intra-, and immediate post-operative periods. Parents of each child completed a questionnaire within 7-10 days post-operatively, describing demographics, type of pre-operative preparation, and post-operative recovery and behavior. Subjects were retrospectively divided into groups according to their type of pre-operative preparation. Data were analyzed with multiple Pearson Correlation coefficients, ANOVA using General Linear Models, and Scheffe's test. There was only one significant difference: the group which played with hospital equipment showed less negative behavior changes at home (p less than .05).