213 research outputs found
The effect of prompts on the shared reading interactions of parents and children with Down syndrome
This study examined the effect of prompts on the shared reading interactions of parents and young children with Down syndrome. Eight parents and their children with Down syndrome (aged 4 years, 7 months to 6 years, 9 months) were recorded reading two books together, one of which included 12 question prompts which parents were instructed to ask their child during reading. Though there was considerable variability, parents and children engaged in significantly more extra-textual talk when reading books with embedded prompts than during typical reading. In addition, children showed greater participation, and produced significantly more words and a greater range of words, when reading books with embedded prompts. Prompts had no effect on the complexity of child language. Embedded prompts significantly enhanced the interactions that occurred between parents and young children with Down syndrome during shared book reading and created more opportunities for parents to support their childβs language development. Though further studies are needed, the findings reported here have potentially important implications for the development of shared reading interventions to support language development in young children with Down syndrome
Stage 1 Registered Report: The relationship between handedness and language ability in children [version 1; referees: 2 approved]
Weak or inconsistent hand preference may be a risk factor for developmental language delay.Β This study will test the extent to which variations in language skills are associated with the strength of hand preference. Data are drawn from a large sample (n = 569) of 6- to 7-year-old children unselected for ability, assessed at two time points, 6 months apart. Hand preference is assessed using the Quantitative Hand Preference task (QHP) and five uni-manual motor tasks. Language skills (expressive and receptive vocabulary, receptive grammar, and morphological awareness) are assessed with standardized measures. If weak cerebral lateralisation (as assessed by the QHP task) is a risk factor for language difficulties, it should be possible to detect such effects in the large representative sample of children examined here
Error-Prone ZW Pairing and No Evidence for Meiotic Sex Chromosome Inactivation in the Chicken Germ Line
In the male mouse the X and Y chromosomes pair and recombine within the small pseudoautosomal region. Genes located on the unsynapsed segments of the X and Y are transcriptionally silenced at pachytene by Meiotic Sex Chromosome Inactivation (MSCI). The degree to which MSCI is conserved in other vertebrates is currently unclear. In the female chicken the ZW bivalent is thought to undergo a transient phase of full synapsis at pachytene, starting from the homologous ends and spreading through the heterologous regions. It has been proposed that the repair of the ZW DNA double-strand breaks (DSBs) is postponed until diplotene and that the ZW bivalent is subject to MSCI, which is independent of its synaptic status. Here we present a distinct model of meiotic pairing and silencing of the ZW pair during chicken oogenesis. We show that, in most oocytes, DNA DSB foci on the ZW are resolved by the end of pachytene and that the ZW desynapses in broad synchrony with the autosomes. We unexpectedly find that ZW pairing is highly error prone, with many oocytes failing to engage in ZW synapsis and crossover formation. Oocytes with unsynapsed Z and W chromosomes nevertheless progress to the diplotene stage, suggesting that a checkpoint does not operate during pachytene in the chicken germ line. Using a combination of epigenetic profiling and RNAβFISH analysis, we find no evidence for MSCI, associated with neither the asynaptic ZW, as described in mammals, nor the synaptic ZW. The lack of conservation of MSCI in the chicken reopens the debate about the evolution of MSCI and its driving forces
Putting episodic disability into context: a qualitative study exploring factors that influence disability experienced by adults living with HIV/AIDS
<p>Abstract</p> <p>Background</p> <p>An increasing number of individuals may be living with the health-related consequences of HIV and its associated treatments, a concept we term disability. However, the context in which disability is experienced from the HIV perspective is not well understood. The purpose of this paper is to describe the contextual factors that influence the experiences of disability from the perspective of adults living with HIV.</p> <p>Methods</p> <p>We conducted four focus groups and 15 face-to-face interviews with 38 men and women living with HIV. We asked participants to describe their health-related challenges, the physical, social and psychological areas of their life affected, and the impact of these challenges on their overall health. We also conducted two validity check focus groups with seven returning participants. We analyzed data using grounded theory techniques to develop a conceptual framework of disability for adults living with HIV, called the Episodic Disability Framework.</p> <p>Results</p> <p>Contextual factors that influenced disability were integral to participants' experiences and emerged as a key component of the framework. Extrinsic contextual factors included social support (support from friends, family, partners, pets and community, support from health care services and personnel, and programme and policy support) and stigma. Intrinsic contextual factors included living strategies (seeking social interaction with others, maintaining a sense of control over life and the illness, "blocking HIV out of the mind", and adopting attitudes and beliefs to help manage living with HIV) and personal attributes (gender and aging). These factors may exacerbate or alleviate dimensions of HIV disability.</p> <p>Conclusion</p> <p>This framework is the first to consider the contextual factors that influence experiences of disability from the perspective of adults living with HIV. Extrinsic factors (level of social support and stigma) and intrinsic factors (living strategies and personal attributes) may exacerbate or alleviate episodes of HIV-related disability. These factors offer a broader understanding of the disability experience and may suggest ways to prevent or reduce disability for adults living with HIV.</p
The Intracellular Transport and Secretion of Calumenin-1/2 in Living Cells
Calumenin isoforms 1 and 2 (calu-1/2), encoded by the CALU gene, belong to the CREC protein family. Calu-1/2 proteins are secreted into the extracellular space, but the secretory process and regulatory mechanism are largely unknown. Here, using a time-lapse imaging system, we visualized the intracellular transport and secretory process of calu-1/2-EGFP after their translocation into the ER lumen. Interestingly, we observed that an abundance of calu-1/2-EGFP accumulated in cellular processes before being released into the extracellular space, while only part of calu-1/2-EGFP proteins were secreted directly after attaching to the cell periphery. Moreover, we found the secretion of calu-1/2-EGFP required microtubule integrity, and that calu-1/2-EGFP-containing vesicles were transported by the motor proteins Kif5b and cytoplasmic dynein. Finally, we determined the export signal of calu-1/2-EGFP (amino acid positions 20β46) and provided evidence that the asparagine at site 131 was indispensable for calu-1/2-EGFP stabilization. Taken together, we provide a detailed picture of the intracellular transport of calu-1/2-EGFP, which facilitates our understanding of the secretory mechanism of calu-1/2
Genetically enhanced asynapsis of autosomal chromatin promotes transcriptional dysregulation and meiotic failure
During meiosis, pairing of homologous chromosomes and their synapsis are essential prerequisites for normal male gametogenesis. Even limited autosomal asynapsis often leads to spermatogenic impairment, the mechanism of which is not fully understood. The present study was aimed at deliberately increasing the size of partial autosomal asynapsis and analysis of its impact on male meiosis. For this purpose, we studied the effect of t12 haplotype encompassing four inversions on chromosome 17 on mouse autosomal translocation T(16;17)43H (abbreviated T43H). The T43H/T43H homozygotes were fully fertile in both sexes, while +/T43H heterozygous males, but not females, were sterile with meiotic arrest at late pachynema. Inclusion of the t12 haplotype in trans to the T43H translocation resulted in enhanced asynapsis of the translocated autosome, ectopic phosphorylation of histone H2AX, persistence of RAD51 foci, and increased gene silencing around the translocation break. Increase was also on colocalization of unsynapsed chromatin with sex body. Remarkably, we found that transcriptional silencing of the unsynapsed autosomal chromatin precedes silencing of sex chromosomes. Based on the present knowledge, we conclude that interference of meiotic silencing of unsynapsed autosomes with meiotic sex chromosome inactivation is the most likely cause of asynapsis-related male sterility
The Dynamism of Organizational Practices: The Role of Employment Blueprints
This paper explores how foundersβ blueprints affect the dynamism of organizational practices, and in particular the capability to sustain as well as change practices. First, a theoretical argument is developed on the critical role of foundersβ blueprints of the employment model, which are difficult to alter and mark firmsβ future paths by affecting the dynamism of organizational practices over an extended period of time. Subsequently, case studies of several organizational practices in three management consulting firms in the USA, the Netherlands and the UK illustrate how foundersβ conceptions of the employment relationship (i.e. their employment model) affect the way in which competing demands of continuity and renewal are addressed. Moreover, engineering- or commitment-oriented blueprints appear to facilitate the capability to adapt, while autocratic blueprints do not
Failure of SOX9 Regulation in 46XY Disorders of Sex Development with SRY, SOX9 and SF1 Mutations
In human embryogenesis, loss of SRY (sex determining region on Y), SOX9 (SRY-related HMG box 9) or SF1 (steroidogenic factor 1) function causes disorders of sex development (DSD). A defining event of vertebrate sex determination is male-specific upregulation and maintenance of SOX9 expression in gonadal pre-Sertoli cells, which is preceded by transient SRY expression in mammals. In mice, Sox9 regulation is under the transcriptional control of SRY, SF1 and SOX9 via a conserved testis-specific enhancer of Sox9 (TES). Regulation of SOX9 in human sex determination is however poorly understood.We show that a human embryonal carcinoma cell line (NT2/D1) can model events in presumptive Sertoli cells that initiate human sex determination. SRY associates with transcriptionally active chromatin in NT2/D1 cells and over-expression increases endogenous SOX9 expression. SRY and SF1 co-operate to activate the human SOX9 homologous TES (hTES), a process dependent on phosphorylated SF1. SOX9 also activates hTES, augmented by SF1, suggesting a mechanism for maintenance of SOX9 expression by auto-regulation. Analysis of mutant SRY, SF1 and SOX9 proteins encoded by thirteen separate 46,XY DSD gonadal dysgenesis individuals reveals a reduced ability to activate hTES.We demonstrate how three human sex-determining factors are likely to function during gonadal development around SOX9 as a hub gene, with different genetic causes of 46,XY DSD due a common failure to upregulate SOX9 transcription
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