Childcare Choices and Early Cognitive Development

<p>This study uses the data from the National Institute for Children Health and Development Study of Early Child Care and Youth Development to evaluate features of wage and childcare price changes that are associated with positive effects on children's early cognitive skills. Identifying beneficial characteristics of changes in market variables is especially relevant in a policy environment where the main priority of tax incentives related to the use of childcare is not facilitating the formation of children's cognitive skills, but reducing reliance on the welfare system through increase in employment among poor households. </p><p>We estimate jointly the discrete household choices related to the employment status of the mother and the use of a paid care mode, the demand functions for quantity and quality of childcare, the production function for cognitive outcomes, the wage process for the mother, and childcare price equations based on the hedonic pricing method, while at the same time introducing unobserved heterogeneity in the disturbance terms of the estimated outcomes. Our strategy for handling selection problems also utilizes the exogenous variation in childcare prices across the 10 geographical markets defined by the study sites in the NICHD SECCYD dataset, which in our model influence choices, but do not affect cognitive outcomes directly.</p><p>Our results show that failing to account for common unobserved characteristics would lead to underestimating the impact of all analyzed wage and price changes. We find that prices and wages do not have a statistically significant impact on the quality of paid care, while the marginal product of that attribute of care is positive for almost all input combinations in the production of cognitive attainment. Therefore, a policy utilizing changes in wages and prices can be effective in improving early cognitive skill only through the impact of those changes on the intensity of paid care use. </p><p>The comparison of the effects of wage and price changes on early cognitive skills for three sets of values of the observable household characteristics representing low, middle and high income households lead to the following conclusions: (1) a tax credit for working mothers and childcare subsidies for center-based care can bring disproportionate gains for children in low and middle income groups; (2) subsidizing paid home care for children less than three and a half years old can be more effective than subsidizing center-based care for the same age group in terms of improving cognitive outcomes at the age of five; (3) conditioning childcare assistance for paid care on the employment status of the mother does not seem to have a strong negative effect on early skill formation; and (4) tax incentives affecting wage rates and childcare prices prove to be beneficial for the formation of early cognitive skills only when they are implemented while the child is less than three and a half years old.</p>Dissertatio

Adult Zebrafish as a Model System for Cutaneous Wound-Healing Research

Upon injury, the skin must quickly regenerate to regain its barrier function. In mammals, wound healing is rapid and scar free during embryogenesis, whereas in adults it involves multiple steps including blood clotting, inflammation, re-epithelialization, vascularization, and granulation tissue formation and maturation, resulting in a scar. We have established a rapid and robust method to introduce full-thickness wounds onto the flank of adult zebrafish, and show that apart from external fibrin clot formation, all steps of adult mammalian wound repair also exist in zebrafish. Wound re-epithelialization is extremely rapid and initiates with no apparent lag phase, subsequently followed by the immigration of inflammatory cells and the formation of granulation tissue, consisting of macrophages, fibroblasts, blood vessels, and collagen. The granulation tissue later regresses, resulting in minimal scar formation. Studies after chemical treatment or with transgenic fish further suggest that wound re-epithelialization occurs independently of inflammation and fibroblast growth factor signaling, whereas both are essential for fibroblast recruitment and granulation tissue formation. Together, these results demonstrate that major steps and principles of cutaneous wound healing are conserved among adult mammals and adult zebrafish, making zebrafish a valuable model for studying vertebrate skin repair

Production of sterile Atlantic salmon by germ cell ablation with antisense oligonucleotides

Cultivation of sterile-only fish in aquaculture offers multiple benefits of environmental, economical, and social value. A reliable method for efficient sterilization without affecting fish welfare and performance traits would have significant impact on fish production practices. Here, we demonstrate sterilization of Atlantic salmon embryos by targeting the dead end gene with antisense oligonucleotides. Successful gene knock down and sterilization was achieved only when using Gapmer oligonucleotides and not with morpholino oligos. Germ cell-depleted embryos developed into morphologically normal male and female salmon with rudimentary gonads devoid of gametes

The Epithelial Cell Adhesion Molecule EpCAM Is Required for Epithelial Morphogenesis and Integrity during Zebrafish Epiboly and Skin Development

The aberrant expression of the transmembrane protein EpCAM is associated with tumor progression, affecting different cellular processes such as cell–cell adhesion, migration, proliferation, differentiation, signaling, and invasion. However, the in vivo function of EpCAM still remains elusive due to the lack of genetic loss-of-function studies. Here, we describe epcam (tacstd) null mutants in zebrafish. Maternal-zygotic mutants display compromised basal protrusive activity and epithelial morphogenesis in cells of the enveloping layer (EVL) during epiboly. In partial redundancy with E-cadherin (Ecad), EpCAM made by EVL cells is further required for cell–cell adhesion within the EVL and, possibly, for proper attachment of underlying deep cells to the inner surface of the EVL, thereby also affecting deep cell epiboly movements. During later development, EpCAM per se becomes indispensable for epithelial integrity within the periderm of the skin, secondarily leading to disrupted morphology of the underlying basal epidermis and moderate hyper-proliferation of skin cells. On the molecular level, EVL cells of epcam mutant embryos display reduced levels of membranous Ecad, accompanied by an enrichment of tight junction proteins and a basal extension of apical junction complexes (AJCs). Our data suggest that EpCAM acts as a partner of E-cadherin to control adhesiveness and integrity as well as plasticity and morphogenesis within simple epithelia. In addition, EpCAM is required for the interaction of the epithelia with underlying cell layers

Decreased striatal monoaminergic terminals in multiple system atrophy detected with positron emission tomography

We examined the density of striatal presynaptic monoaminergic terminals, using a ligand for the type 2 vesicular monoamine transporter, (+)-[ 11 C]dihydrotetrabenazine, with positron emission tomography in 7 normal control subjects, 8 multiple system atrophy (MSA) patients with predominantly parkinsonian features (MSA-P), 8 MSA patients with principally cerebellar dysfunction (MSA-C), and 6 sporadic olivopontocerebellar atrophy (sOPCA) patients. The findings were correlated with the results of neurological evaluations and magnetic resonance imaging studies. Specific binding was significantly reduced in the putamen of all patient groups in the order MSA-P < MSA-C < sOPCA, compared with controls. Mean blood-to-brain ligand transport (K 1 ) was significantly decreased in the putamen of all patient groups and in the cerebellar hemispheres of MSA-C and sOPCA but not MSA-P groups, compared with controls. Significant negative correlations were found between striatal binding and the intensity of parkinsonian features and between cerebellar K 1 and the intensity of cerebellar dysfunction. The results suggest fundamental differences between MSA-P and MSA-C groups reflecting differential severity of degeneration of nigrostriatal and cerebellar systems in these two forms of MSA. The findings also show that some sOPCA patients have subclinical nigrostriatal dysfunction and are at risk of developing MSA with disease progression. Ann Neurol 1999;45:769–777Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34881/1/11_ftp.pd

Laser capture microdissection of gonads from juvenile zebrafish

<p>Abstract</p> <p>Background</p> <p>Investigating gonadal gene expression is important in attempting to elucidate the molecular mechanism of sex determination and differentiation in the model species zebrafish. However, the small size of juvenile zebrafish and correspondingly their gonads complicates this type of investigation. Furthermore, the lack of a genetic sex marker in juvenile zebrafish prevents pooling gonads from several individuals. The aim of this study was to establish a method to isolate the gonads from individual juvenile zebrafish allowing future investigations of gonadal gene expression during sex determination and differentiation.</p> <p>Methods</p> <p>The laser capture microdissection technique enables isolation of specific cells and tissues and thereby removes the noise of gene expression from other cells or tissues in the gene expression profile. A protocol developed for laser microdissection of human gonocytes was adjusted and optimised to isolate juvenile zebrafish gonads.</p> <p>Results</p> <p>The juvenile zebrafish gonad is not morphologically distinguishable when using dehydrated cryosections on membrane slides and a specific staining method is necessary to identify the gonads. The protocol setup in this study allows staining, identification, isolation and subsequent RNA purification and amplification of gonads from individual juvenile zebrafish thereby enabling gonadal gene expression profiling.</p> <p>Conclusion</p> <p>The study presents a protocol for isolation of individual juvenile zebrafish gonads, which will enable future investigations of gonadal gene expression during the critical period of sex differentiation. Furthermore, the presented staining method is applicable to other species as it is directed towards alkaline phosphatase that is expressed in gonocytes and embryonic stem cells, which is conserved among vertebrate species.</p

Genetic Analysis of Fin Development in Zebrafish Identifies Furin and Hemicentin1 as Potential Novel Fraser Syndrome Disease Genes

Using forward genetics, we have identified the genes mutated in two classes of zebrafish fin mutants. The mutants of the first class are characterized by defects in embryonic fin morphogenesis, which are due to mutations in a Laminin subunit or an Integrin alpha receptor, respectively. The mutants of the second class display characteristic blistering underneath the basement membrane of the fin epidermis. Three of them are due to mutations in zebrafish orthologues of FRAS1, FREM1, or FREM2, large basement membrane protein encoding genes that are mutated in mouse bleb mutants and in human patients suffering from Fraser Syndrome, a rare congenital condition characterized by syndactyly and cryptophthalmos. Fin blistering in a fourth group of zebrafish mutants is caused by mutations in Hemicentin1 (Hmcn1), another large extracellular matrix protein the function of which in vertebrates was hitherto unknown. Our mutant and dose-dependent interaction data suggest a potential involvement of Hmcn1 in Fraser complex-dependent basement membrane anchorage. Furthermore, we present biochemical and genetic data suggesting a role for the proprotein convertase FurinA in zebrafish fin development and cell surface shedding of Fras1 and Frem2, thereby allowing proper localization of the proteins within the basement membrane of forming fins. Finally, we identify the extracellular matrix protein Fibrillin2 as an indispensable interaction partner of Hmcn1. Thus we have defined a series of zebrafish mutants modelling Fraser Syndrome and have identified several implicated novel genes that might help to further elucidate the mechanisms of basement membrane anchorage and of the disease's aetiology. In addition, the novel genes might prove helpful to unravel the molecular nature of thus far unresolved cases of the human disease

HuB (elavl2) mRNA Is Restricted to the Germ Cells by Post-Transcriptional Mechanisms including Stabilisation of the Message by DAZL

The ability of germ cells to carry out a gene regulatory program distinct from the surrounding somatic tissue, and their capacity to specify an entire new organism has made them a focus of many studies that seek to understand how specific regulatory mechanisms, particularly post-transcriptional mechanisms, contribute to cell fate. In zebrafish, germ cells are specified through the inheritance of cytoplasmic determinants, termed the germ plasm, which contains a number of maternal mRNAs and proteins. Investigation of several of these messages has revealed that the restricted localisation of these mRNAs to the germ plasm and subsequent germ cells is due to cis-acting sequence elements present in their 3′UTRs. Here we show that a member of the Hu family of RNA-binding proteins, HuB, is maternally provided in the zebrafish embryo and exhibits germ cell specific expression during embryogenesis. Restriction of HuB mRNA to the germ cells is dependent on a number of sequence elements in its 3′UTR, which act to degrade the mRNA in the soma and stabilise it in the germ cells. In addition, we show that the germ cell specific RNA-binding protein DAZL is able to promote HuB mRNA stability and translation in germ cells, and further demonstrate that these activities require a 30 nucleotide element in the 3′UTR. Our study suggests that DAZL specifically binds the HuB 3′UTR and protects the message from degradation and/or enhances HuB translation, leading to the germ cell specific expression of HuB protein