335 research outputs found

    A Qualitative Analysis of the Impact of the Reform of the College of Science Undergraduate Core Curriculum at State University

    Get PDF
    The Dean of the College of Science at State University, a large public Midwestern research university, in a memo to the faculty and staff initiated what he called a review of the undergraduate science core curriculum. He formed a task force that was to investigate on three issues; a reassessment of the undergraduate core curriculum, the recruitment and retention of qualified undergraduate students with an emphasis on diversity, and strategies that would address these issues. The age of the curriculum, 40 years since the last significant change, was an important factor in the review of the curriculum. This qualitative study seeks to understand how a group of four administrators and five faculty, all from the College of Science, participated in the task force, perceived the old curriculum, and perceived the changes made and the resulting new curriculum. They were also asked to rank both the prior and new curricula. As part of an ongoing theme in higher education they were also asked if they thought the changes made to the curriculum qualified as reform and why or why not. This resulted in a discussion of what a reform might look like at State University and ultimately a definition of reform

    Squeeze flow of stress power law fluids

    Get PDF

    Hypoxia-inducible factor 1α is a new target of microphthalmia-associated transcription factor (MITF) in melanoma cells

    Get PDF
    In melanocytes and melanoma cells α-melanocyte stimulating hormone (α-MSH), via the cAMP pathway, elicits a large array of biological responses that control melanocyte differentiation and influence melanoma development or susceptibility. In this work, we show that cAMP transcriptionally activates Hif1a gene in a melanocyte cell–specific manner and increases the expression of a functional hypoxia-inducible factor 1α (HIF1α) protein resulting in a stimulation of Vegf expression. Interestingly, we report that the melanocyte-specific transcription factor, microphthalmia-associated transcription factor (MITF), binds to the Hif1a promoter and strongly stimulates its transcriptional activity. Further, MITF “silencing” abrogates the cAMP effect on Hif1a expression, and overexpression of MITF in human melanoma cells is sufficient to stimulate HIF1A mRNA. Our data demonstrate that Hif1a is a new MITF target gene and that MITF mediates the cAMP stimulation of Hif1a in melanocytes and melanoma cells. Importantly, we provide results demonstrating that HIF1 plays a pro-survival role in this cell system. We therefore conclude that the α-MSH/cAMP pathway, using MITF as a signal transducer and HIF1α as a target, might contribute to melanoma progression

    Neprilysin, a Novel Target for Ultraviolet B Regulation of Melanogenesis Via Melanocortins

    Get PDF
    SummaryCompelling evidence suggest a role for melanocortins in the regulation of melanogenesis by ultraviolet radiation. Within the epidermis, melanocytes and keratinocytes produce α-melanocyte-stimulating hormone and adrenocorticotropic hormone. The persistence and the strength of the biologic signal delivered by these peptides depend on their local concentration, which is controlled by the rate of peptide production and by the rate of its degradation. In this study, we investigated the mechanism of melanocortin degradation by melanocytes and the effect of ultraviolet on this process. We have focused our attention on a neutral endopeptidase, neprilysin, which has been implicated in the ending of numerous peptidergic signals. We have shown that this enzyme is expressed at the surface of human melanocytes. Interestingly, its activity and its expression are dramatically downregulated by ultraviolet B treatment. Moreover, in the presence of phosphoramidon, a stable inhibitor of neprilysin, we observed an increased efficiency of α-melanocyte-stimulating hormone and adrenocorticotropic hormone to stimulate both tyrosinase activity and microphthalmia expression. Taken together, these data indicate that neprilysin expressed by melanocytes has a physiologic role in the regulation of melanogenesis by proopiomelanocortin peptide. Further, its downregulation by ultraviolet B irradiation shed light on a new and appealing mechanism of ultraviolet B induced melanogenesis via the control of melanocortins degradation

    Les grandes aventures des petits héros scandinaves

    Get PDF
    Qu’est-ce que l’hĂ©roĂŻsme fait aux notions d’enfance et de mineur ? Que dit un jeune hĂ©ros de la littĂ©rature, de la culture et du public d’un pays ? D’ailleurs, est-il correct de parler de littĂ©rature, de culture et du public par rapport Ă  un pays particulier dans le cas de la littĂ©rature de jeunesse ? En proposant une approche Ă©pistĂ©mologique et thĂ©orique Ă  ces questions, nous analysons dans notre article ces pistes qui concernent la littĂ©rature de jeunesse et le petit hĂ©ros scandinave. L’hĂ©roĂŻsme permet-il au jeune hĂ©ros de faire de la littĂ©rature scandinave une « littĂ©rature majeure » dans l’imaginaire europĂ©en ?What does heroism do to the notions of childhood and minor ? What does a young hero of a national literature, culture and public mean ? Is it right to define literature, culture and the public in relation to a particular country in the case of children’s literature ? By proposing an epistemological and theoretical approach to these questions, we analyze in our article these subjects that concern literature for children and the little Scandinavian hero. Does the heroism of a young hero allow Scandinavian literature to become a “major literature” in the European literary imagination 

    Enhanced Binding of Poly(ADP-ribose)polymerase-1 and Ku80/70 to the ITGA2 Promoter via an Extended Cytosine-Adenosine Repeat

    Get PDF
    Background: We have identified a cytosine-adenosine (CA) repeat length polymorphism in the 59-regulatory region of the human integrin a2 gene ITGA2 that begins at 2605. Our objective was to establish the contribution of this polymorphism to the regulation of integrin a2b1 expression, which is known to vary several-fold among normal individuals, and to investigate the underlying mechanism(s). Methodology/Principal Findings: In combination with the SNP C-52T, previously identified by us as a binding site for the transcription factor Sp1, four ITGA2 haplotypes can be distinguished, in the order in which they enhance ITGA2 transcription: (CA)12/-52C.(CA)11/-52C.(CA)11/-52T.(CA)10/-52T. By DNA affinity chromatography and chromatin immunoprecipitation (ChIP) assays, we show that poly (ADP-ribose)polymerase-1 (PARP-1) and Ku80/70 bind specifically and with enhanced affinity to the longer (CA)12 repeat alleles. Conclusions/Significance: The increased binding of PARP-1 and Ku80/70, known components of transcription co-activator complexes, to the longer (CA)12 alleles of ITGA2 coincides with enhanced a2b1 expression. The most likely explanation for these findings is that PARP-1 and Ku80/70 contribute to the transcriptional regulation of ITGA2. These observations provide new insight into the mechanisms(s) underlying haplotype-dependent variability in integrin a2b1 expression in huma

    Microphthalmia-associated transcription factor regulates RAB27A gene expression and controls melanosome transport.

    Get PDF
    Melanosomes are lysosome-related organelles specialized in melanin synthesis and transport. In this study, we show that microphthalmia-associated transcription factor (MITF) silencing induces melanosome gathering around the nucleus and causes the relocalization of Rab27A, Slac2a-Mlph, and Myo5a that control the transport of melanosomes on the actin network. In an attempt to elucidate the mechanism by which MITF controls melanosome distribution, we identify RAB27A as a new MITF target gene. Indeed, MITF silencing leads to a dramatic decrease in Rab27A expression and blocks the stimulation of Rab27A expression evoked by cAMP. Further, forced expression of MITF increases Rab27A expression, indicating that MITF is required and sufficient for Rab27A expression in melanoma cells. MITF binds to two E-boxes in the proximal region of the Rab27A promoter and stimulates its transcriptional activity. Finally, re-expression of Rab27A, in MITF-depleted cells, restores the transport of melanosomes to the cell periphery. These results show that RAB27A is a new direct transcriptional target of MITF and link MITF to melanosome transport, another key parameter of melanocyte differentiation and skin pigmentation. Interestingly, Rab27A is involved in other fundamental physiological functions, such as the transport of lytic granules and insulin secretion. Thus our results, deciphering the mechanism of Rab27A transcriptional regulation, have an interest that goes beyond the skin pigmentation field

    Risk of hematological malignancies associated with magnetic fields exposure from power lines: a case-control study in two municipalities of northern Italy

    Get PDF
    BackgroundSome epidemiologic studies have suggested an association between electromagnetic field exposure induced by high voltage power lines and childhood leukemia, but null results have also been yielded and the possibility of bias due to unmeasured confounders has been suggested.MethodsWe studied this relation in the Modena and Reggio Emilia municipalities of northern Italy, identifying the corridors along high voltage power lines with calculated magnetic field intensity in the 0.1-<0.2, 0.2-<0.4, and ≄ 0.4 microTesla ranges. We identified 64 cases of newly-diagnosed hematological malignancies in children aged <14 within these municipalities from 1986 to 2007, and we sampled four matched controls for each case, collecting information on historical residence and parental socioeconomic status of these subjects.ResultsRelative risk of leukemia associated with antecedent residence in the area with exposure ≄ 0.1 microTesla was 3.2 (6.7 adjusting for socioeconomic status), but this estimate was statistically very unstable, its 95% confidence interval being 0.4-23.4, and no indication of a dose-response relation emerged. Relative risk for acute lymphoblastic leukemia was 5.3 (95% confidence interval 0.7-43.5), while there was no increased risk for the other hematological malignancies.ConclusionsThough the number of exposed children in this study was too low to allow firm conclusions, results were more suggestive of an excess risk of leukemia among exposed children than of a null relation

    Rab27a: A key to melanosome transport in human melanocytes

    Full text link
    Normal pigmentation depends on the uniform distribution of melanin-containing vesicles, the melanosomes, in the epidermis. Griscelli syndrome (GS) is a rare autosomal recessive disease, characterized by an immune deficiency and a partial albinism that has been ascribed to an abnormal melanosome distribution. GS maps to 15q21 and was first associated with mutations in the myosin-V gene. However, it was demonstrated recently that GS can also be caused by a mutation in the Rab27a gene. These observations prompted us to investigate the role of Rab27a in melanosome transport. Using immunofluorescence and immunoelectron microscopy studies, we show that in normal melanocytes Rab27a colocalizes with melanosomes. In melanocytes isolated from a patient with GS, we show an abnormal melanosome distribution and a lack of Rab27a expression. Finally, reexpression of Rab27a in GS melanocytes restored melanosome transport to dendrite tips, leading to a phenotypic reversion of the diseased cells. These results identify Rab27a as a key component of vesicle transport machinery in melanocytes
    • 

    corecore