In vivo tracing of canonical Wnt signaling in Xenopus tadpoles by means of an inducible transgenic reporter tool

The canonical Wnt pathway is recurrently used during embryogenesis and adult life. To track the cellular output of Wnt signaling in a living organism, we designed a hormone-inducible Wnt responsive system, capable to dynamically and specifically report Wnt pathway activities through eGFP expression. In contrast to previous in vivo reporters, our system essentially avoids interference of consecutive signals by remaining dormant until addition of hormone, which makes it a valuable tool to map canonical Wnt signaling in post-embryonic stages. Transgenic Xenopus laevis embryos were analyzed revealing at tadpole stage in specific tissues and organs cell populations with high Wnt pathway activity.     

The role of teachers' expectations in the association between children's SES and performance in kindergarten: a moderated mediation analysis

This study examines the role of teachers' expectations in the association between children's socio-economic background and achievement outcomes. Furthermore, the role of children's ethnicity in moderating this mediated relation is investigated. In the present study, 3,948 children from kindergarten are examined. Data are analysed by means of structural equation modeling. First, results show that teachers' expectations mediate the relation between children's SES and their later language and math achievement, after controlling for children's ethnicity, prior achievement and gender. This result indicates that teachers may exacerbate individual differences between children. Second, children's ethnicity moderates the mediation effect of teachers' expectations with respect to math outcomes. The role of teachers' expectations in mediating the relation between SES and math outcomes is stronger for majority children than for minority children.     

Requirement of Wnt/β-catenin signaling in pronephric kidney development

The pronephric kidney controls water and electrolyte balance during early fish and amphibian embryogenesis. Many Wnt signaling components have been implicated in kidney development. Specifically, in Xenopus pronephric development as well as the murine metanephroi, the secreted glycoprotein Wnt-4 has been shown to be essential for renal tubule formation. Despite the importance of Wnt signals in kidney organogenesis, little is known of the definitive downstream signaling pathway(s) that mediate their effects. Here we report that inhibition of Wnt/β-catenin signaling within the pronephric field of Xenopus results in significant losses to kidney epithelial tubulogenesis with little or no effect on adjoining axis or somite development. We find that the requirement for Wnt/β-catenin signaling extends throughout the pronephric primordium and is essential for the development of proximal and distal tubules of the pronephros as well as for the development of the duct and glomus. Although less pronounced than effects upon later pronephric tubule differentiation, inhibition of the Wnt/β-catenin pathway decreased expression of early pronephric mesenchymal markers indicating it is also needed in early pronephric patterning. We find that upstream inhibition of Wnt/β-catenin signals in zebrafish likewise reduces pronephric epithelial tubulogenesis. We also find that exogenous activation of Wnt/β-catenin signaling within the Xenopus pronephric field results in significant tubulogenic losses. Together, we propose Wnt/β-catenin signaling is required for pronephric tubule, duct and glomus formation in Xenopus laevis, and this requirement is conserved in zebrafish pronephric tubule formation.     

Role of the 2 zebrafish survivin genes in vasculo-angiogenesis, neurogenesis, cardiogenesis and hematopoiesis

Background  

Normal growth and development of organisms requires maintenance of a dynamic balance between systems that promote cell survival and those that induce apoptosis. The molecular mechanisms that regulate these processes remain poorly understood, and thus further in vivo study is required. Survivin is a member of the inhibitor of apoptosis protein (IAP) family, that uniquely also promotes mitosis and cell proliferation. Postnatally, survivin is hardly detected in most tissues, but is upregulated in all cancers, and as such, is a potential therapeutic target. Prenatally, survivin is also highly expressed in several tissues. Fully delineating the properties of survivin in vivo in mice has been confounded by early lethal phenotypes following survivin gene inactivation.     

First-Time Parents Are Not Well Enough Prepared for the Safety of Their Infant

Background

Unintentional falls and poisonings are major causes of death and disability among infants. Although guidelines are available to prevent these injuries, safety behaviours are not performed by parents, causing unnecessary risks. Little is known about safety behaviours of first-time parents and whether they behave according to these guidelines.

Aims/Objectives/Purpose

The objective of this study was to compare safety behaviours of first-time parents with those of non-first-time parents and to determine correlates of unsafe behaviour of parents of infants. We used self-report questionnaires to assess safety behaviours in a cross-sectional study sample.

Methods

A total of 1439 parents visiting a preventive youth healthcare centre in the Netherlands were invited to complete a questionnaire with regard to the prevention of falls and poisonings. Parents were categorized into first-time parents and non-first-time parents. Correlates of parents'' child safety behaviours were determined using multiple logistic regression analyses.

Results/Outcome

Most respondents were mothers (93.2%); 48.2% of families were first-time parents. The mean age of the infants was 7.2 months (SD 1.1; range 4–12), 51.8% were boys, and 34.5% of infants could crawl. First-time parents were more likely not to have a stair gate installed (OR 16.46; 95% CI 12.36–21.93); were more likely to store cleaning products unsafely (OR 4.55; 95% CI 3.59–5.76); and were more likely to store medicines unsafely (OR 2.90; 95% CI 2.31–3.63) than non-first-time parents. First-time parents were more likely to not have a window guard installed (OR 1.52; 95% CI 1.08–2.15) (all P<0.05).

Discussion/Conclusion

First-time parents are not well prepared for the safety of their infant, causing unnecessary risks. The various parents'' safety behaviours were influenced by different variables, for example, age of the infant, crawling of the infant, mother''s educational level, mother''s ethnicity, self-efficacy, vulnerability, severity.     

Self-exploding lipid-coated microgels

Self-exploding microparticles show potential for advanced delivery of certain therapeutics. This study evaluates (1) whether degrading biodegradable dextran hydroxyethyl methacrylate (dex-HEMA) microgels can be coated by a lipid membrane and (2) whether the surrounding membrane can be ruptured by the increasing swelling pressure of the degrading microgel. We found that adsorption of charged liposomes to oppositely charged dex-HEMA microgels provides efficient coating of the microgels, whereby microparticles with a "core-shell" structure were clearly obtained. Especially, we could confirm experimentally that the swelling pressure increase of degrading dex-HEMA microgels can destroy the lipid membrane surrounding the microgels.