A longitudinal analysis of prenatal exposure to methylmercury and fatty acids in the Seychelles

Background

Maternal fish consumption during pregnancy exposes the fetus simultaneously to methylmercury (MeHg) and long chain polyunsaturated fatty acids (LCPUFA). Data from the Seychelles Child Development Nutrition Study (SCDNS) showed a negative association of MeHg with child development when children were 30 months of age, only when controlling for LCPUFA. Concomitantly, n − 3 LCPUFA were found to have a significant positive association only at 9 months. These findings suggest that the effects of MeHg and LCPUFA may vary with age over the first few years of life. We address this by including outcomes at two ages and adjusting for the child's age at testing.

Methods

A longitudinal analysis utilizing linear mixed models was performed to assess the associations of maternal hair total mercury (THg, a biomarker for MeHg) and maternal LCPUFA with children's Bayley Scales of Infant Development Psychomotor Developmental Index (BSID-II PDI) at 9 and 30 months of age, and to determine whether these associations change over time. Data from 228 children were included.

Results

Maternal hair MeHg had a negative effect on BSID PDI, while maternal n − 3 LCPUFA had a positive effect. These effects did not change significantly from 9 to 30 months in this analysis.

Conclusions

The longitudinal analysis provides increased power for estimating the relationships of prenatal MeHg and LCPUFA exposures during child development. Significant associations of these exposures in opposite directions confirm the importance of LCPUFA in development and the need to adjust for maternal nutrition when studying prenatal MeHg exposure.     

The interactive effect of change in perceived stress and trait anxiety on vagal recovery from cognitive challenge

The present study tested the hypothesis that the change in state negative affect (measured as perceived stress) after cognitive challenge moderates the relationship of trait anxiety and anger to vagal recovery from that challenge.Cardiac vagal control (assessed using heart rate variability) and respiratory rate were measured in a sample of 905 participants from the Midlife in the United States Study. Cognitive challenges consisted of computerized mental arithmetic and Stroop color–word matching tasks. Multiple regression analyses controlling for the effects of the demographic, lifestyle, and medical factors influencing cardiac vagal control showed a significant moderating effect of change in perceived stress on the relationship of trait anxiety to vagal recovery from cognitive challenges (Beta = .253, p = .013). After adjustment for respiratory rate, this effect became marginally significant (Beta = .177, p = .037). In contrast, for the relationship of trait anger to vagal recovery, this effect was not significant either before (Beta = .141, p = .257) or after (Beta = .186, p = .072) adjusting for respiratory rate. Secondary analyses revealed that among the individuals with higher levels of trait anxiety, greater reductions in perceived stress were associated with greater increases in cardiac vagal control after the challenge. In contrast, among the individuals with lower levels of trait anxiety, changes in perceived stress had no impact on vagal recovery. Therefore, change in perceived stress moderates the relationship of trait anxiety, but not trait anger, to vagal recovery from cognitive challenge.     

Beyond the numbers: Papua New Guinean perspectives on the major health conditions and programs of the country

How members of the community perceive and respond to diseases and health problems are important variables to take into account when planning interventions and priorities in a health system. This paper summarizes some qualitative research undertaken in 2001 and 2002 in Papua New Guinea as part of the formative research for health promotion activity development for immunization, maternal health, tuberculosis and malaria services. It provides some highlights of the health beliefs and health-seeking behaviours amongst a range of urban and rural populations in a range of provinces in Papua New Guinea (PNG), and across a range of age groups including young adults. The findings reinforce that these health-related issues are seen by most of the population as important, although maternal health lags behind, especially in male respondents' perspectives. However, how they respond varies often with the planned health system interventions, and these differences need to be understood and addressed in order to increase the acceptability and efficiency of health services in PNG.     

Emotion recognition following human pulvinar damage

Pulvinar activation has been observed while viewing fearful expressions, but the necessity of this activation to their recognition has not been previously assessed. We measured the processing of emotional facial expressions in a rare patient with complete unilateral loss of the pulvinar. With brief presentations, patient CJ was incapable of recognizing fearful expressions in his contralesional field. Three other patients, with damage limited to the anterior and to the lateral pulvinar, showed no deficits in recognition. In conjunction with anatomical studies of the monkey pulvinar, these results suggest that fear recognition is mediated by the human medial pulvinar. We outline the possible role of the pulvinar in fear recognition, considering both the pulvinar's direct and indirect cortical connections with the amygdala, and we suggest that the integrative role of the pulvinar may be primary. Our results suggest that the cortex in isolation from the entire pulvinar is incapable of recognizing fearful expressions.     

Who gains or who loses weight? Psychosocial factors among first-year university students

Self-reported weight changes over 7 months and their relation to psychosocial characteristics (self-esteem, depression, social support, perceived stress and transition perception) and eating attitudes and behaviors (restrained eating and Eating Disorder Inventory subscales [EDI]) were assessed in first-year male and female students at six Canadian universities (N=2753). Results showed small but significant weight increases over time in males and females (M=1.5 kg). Males who lost weight versus those who gained reported greater negative well-being and more negative feelings about university transition. Females who either lost or gained weight had higher initial restraint and EDI scores than did weight maintainers. At 3 months, total EDI and body dissatisfaction increased in female weight gainers compared to weight losers, plus greater drive for thinness compared to weight maintainers. Thus, males distressed at the transition from high school to university appear more likely to lose weight while well-adjusted males are more likely to gain weight. For females, however, weight gain is associated with more negative well-being and preoccupations with weight and eating.     

Ontogeny of Rat Recognition Memory measured by the novel object recognition task

Detection of novelty is an essential component of recognition memory, which develops throughout cerebral maturation. To better understand the developmental aspects of this memory system, the novel object recognition task (NOR) was used with the immature rat and ontogenically profiled. It was hypothesized that object recognition would vary across development and be inferior to adult performance. The NOR design was made age‐appropriate by downsizing the testing objects and arena. Weanling (P20–23), juvenile (P29–40), and adult (P50+) rats were tested after 0.25, 1, 24, and 48 hr delays. Weanlings exhibited novel object recognition at 0.25 and 1 hr, while older animals showed a preference for the novel object out to 24 hr. These findings are consistent with previous research performed in humans and monkeys, as well as to studies using the NOR after medial temporal lobe damage in adult rats. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 672–678, 2009     

Modification of the L1-CAM carboxy-terminus in pancreatic adenocarcinoma cells

The neural cell adhesion molecule L1 has recently been shown to be expressed in pancreatic adenocarcinoma (PDAC) cells. In this report, we demonstrate that L1 is expressed by moderately- to poorly-differentiated PDAC cells in situ, and that L1 expression is a predictor of poor patient survival. In vitro, reduced reactivity of an anti-L1 carboxy-terminus-specific antibody was observed in the more poorly differentiated fast-growing (FG) variant of the COLO357 population, versus its well-differentiated slow-growing (SG) counterpart, even though they express equivalent total L1. The carboxy-terminus of L1 mediates binding to the MAP kinase-regulating protein RanBPM and mutation of T1247/S1248 within this region attenuates the expression of malignancy associated proteins and L1-induced tumorigenicity in mice. Therefore, we reasoned that the differential epitope exposure observed might be indicative of modifications responsible for regulating these events. However, epitope mapping demonstrated that the major determinant of binding was actually N1251; mutation of T1247 and S1248, alone or together, had little effect on C20 binding. Moreover, cluster assays using CD25 ectodomain/L1 cytoplasmic domain chimeras demonstrated the N1251-dependent, RanBPM-independent stimulation of erk phosphorylation in these cells. Reactivity of this antibody also reflects the differential exposure of extracellular epitopes in these COLO357 sublines, consistent with the previous demonstration of L1 ectodomain conformation modulation by intracellular modifications. These data further support a central role for L1 in PDAC, and define a specific role for carboxy-terminal residues including N1251 in the regulation of L1 activity in PDAC cells.