43 research outputs found
Expression of the gene for main intrinsic polypeptide (MIP): separate spatial distributions of MIP and beta-crystallin gene transcripts in rat lens development
The main intrinsic polypeptide (MIP) is the major protein present in the lens fiber cell membrane and is the product of a gene which, as far as is known, is expressed only in the lens. We have used in situ hybridization and immunofluorescence microscopy to characterize the expression of this gene during the course of development in the rat. At progressive stages of lens morphogenesis, we find that synthesis of the protein is closely tied to the accumulation of MIP mRNA in cells that are committed to terminal differentiation, first in the elongating presumptive primary lens fibers and later in the secondary fibers as they differentiate from the anterior epithelial cells. The transcripts accumulate in the basal cytoplasm of the primary fibers and in the cytoplasm which surrounds the cell nucleus in the secondary fibers. We have compared this pattern of expression with that of a gene for a cytoplasmic protein, beta-crystallin beta-A1/A3. In sharp contrast to the localized concentrations seen for the MIP mRNA, beta-A1/A3 transcripts are relatively uniformly distributed throughout the cytoplasm. Neither MIP nor crystallin gene appears to be transcriptionally active in the undifferentiated epithelial cell, but transcripts from the beta-A1/A3 gene appear earlier in fiber cell differentiation than do those from the gene for MIP
Interleukin-33 Contributes Toward Loss of Tolerance by Promoting B-Cell-Activating Factor of the Tumor-Necrosis-Factor Family (BAFF)-Dependent Autoantibody Production
Breaking tolerance is a key event leading to autoimmunity, but the exact mechanisms responsible for this remain uncertain. Here we show that the alarmin IL-33 is able to drive the generation of autoantibodies through induction of the B cell survival factor BAFF. A temporary, short-term increase in IL-33 results in a primary (IgM) response to self-antigens. This transient DNA-specific autoantibody response was dependent on the induction of BAFF. Notably, radiation resistant cells and not myeloid cells, such as neutrophils or dendritic cells were the major source of BAFF and were critical in driving the autoantibody response. Chronic exposure to IL-33 elicited dramatic increases in BAFF levels and resulted in elevated numbers of B and T follicular helper cells as well as germinal center formation. We also observed class-switching from an IgM to an IgG DNA-specific autoantibody response. Collectively, the results provide novel insights into a potential mechanism for breaking immune-tolerance via IL-33-mediated induction of BAFF
Tet2 disruption leads to enhanced self-renewal and altered differentiation of fetal liver hematopoietic stem cells
Somatic mutation of ten-eleven translocation 2 (TET2) gene is frequently found in human myeloid malignancies. Recent reports showed that loss of Tet2 led to pleiotropic hematopoietic abnormalities including increased competitive repopulating capacity of bone marrow (BM) HSCs and myeloid transformation. However, precise impact of Tet2 loss on the function of fetal liver (FL) HSCs has not been examined. Here we show that disruption of Tet2 results in the expansion of Lin−Sca-1+c-Kit+ (LSK) cells in FL. Furthermore, Tet2 loss led to enhanced self-renewal and long-term repopulating capacity of FL-HSCs in in vivo serial transplantation assay. Disruption of Tet2 in FL also led to altered differentiation of mature blood cells, expansion of common myeloid progenitors and increased resistance for hematopoietic progenitor cells (HPCs) to differentiation stimuli in vitro. These results demonstrate that Tet2 plays a critical role in homeostasis of HSCs and HPCs not only in the BM, but also in FL
Generic health literacy measurement instruments for children and adolescents:a systematic review of the literature
Background Health literacy is an important health promotion concern and recently children and adolescents have been the focus of increased academic attention. To assess the health literacy of this population, researchers have been focussing on developing instruments to measure their health literacy. Compared to the wider availability of instruments for adults, only a few tools are known for younger age groups. The objective of this study is to systematically review the field of generic child and adolescent health literacy measurement instruments that are currently available. Method A systematic literature search was undertaken in five databases (PubMed, CINAHL, PsycNET, ERIC, and FIS) on articles published between January 1990 and July 2015, addressing children and adolescents ?18 years old. Eligible articles were analysed, data was extracted, and synthesised according to review objectives. Results Fifteen generic health literacy measurement instruments for children and adolescents were identified. All, except two, are self-administered instruments. Seven are objective measures (performance-based tests), seven are subjective measures (self-reporting), and one uses a mixed-method measurement. Most instruments applied a broad and multidimensional understanding of health literacy. The instruments were developed in eight different countries, with most tools originating in the United States (n =?6). Among the instruments, 31 different components related to health literacy were identified. Accordingly, the studies exhibit a variety of implicit or explicit conceptual and operational definitions, and most instruments have been used in schools and other educational contexts. While the youngest age group studied was 7-year-old children within a parent-child study, there is only one instrument specifically designed for primary school children and none for early years. Conclusions Despite the reported paucity of health literacy research involving children and adolescents, an unexpected number of health literacy measurement studies in children?s populations was found. Most instruments tend to measure their own specific understanding of health literacy and not all provide sufficient conceptual information. To advance health literacy instruments, a much more standardised approach is necessary including improved reporting on the development and validation processes. Further research is required to improve health literacy instruments for children and adolescents and to provide knowledge to inform effective interventionspublishersversionPeer reviewe
TET1 and hydroxymethylcytosine in transcription and DNA methylation fidelity
Enzymes catalysing the methylation of the 5-position of cytosine (mC) have essential roles in regulating gene expression and maintaining cellular identity. Recently, TET1 was found to hydroxylate the methyl group of mC, converting it to 5-hydroxymethyl cytosine (hmC). Here we show that TET1 binds throughout the genome of embryonic stem cells, with the majority of binding sites located at transcription start sites (TSSs) of CpG-rich promoters and within genes. The hmC modification is found in gene bodies and in contrast to mC is also enriched at CpG-rich TSSs. We provide evidence further that TET1 has a role in transcriptional repression. TET1 binds a significant proportion of Polycomb group target genes. Furthermore, TET1 associates and colocalizes with the SIN3A co-repressor complex. We propose that TET1 fine-tunes transcription, opposes aberrant DNA methylation at CpG-rich sequences and thereby contributes to the regulation of DNA methylation fidelity
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
A study on celebrity equity.
In this study, we adopted and applied Aaker’s Brand Equity Model [Aaker, 1991] to develop a measure of celebrity success. We investigate the extent to which factors such as loyalty to celebrity, awareness of celebrity, celebrity authenticity and celebrity associations have an impact on the success of celebrities. This success is measured by two dimensions: (1) purchase intention of the celebrity’s next album and (2) purchase intention of his endorsed product.
We first used a focus group interview to gain a better understanding of our target respondents’ preferences and perceptions in regard to celebrities in the Mandarin music industry and used the insights we obtained to develop our survey questionnaire. An online self-administered survey was then conducted and we obtained a total of 172 usable responses for the analysis.
Our findings showed that there is a significant relationship between loyalty to celebrity and the success of celebrity in terms of consumers’ purchase intention of the celebrity’s next album. Following that, we discuss the managerial implications of our results as well as ways on how relevant stakeholders can leverage on our findings.BUSINES
Statistical methods for discovery sampling.
This research project first presents an overview of discovery sampling, a sampling method that can be used in an audit. It also highlights the various probability distributions that are used in fixed sample size discovery sampling, including the hypergeometric, binomial and poisson distribution. The project also discusses the use of sequential sampling approach in discovery sampling and concludes with a recommendation of the most appropriate statistical method