2,376 research outputs found

    Cooperation of Gq, Gi, and G12/13 in Protein Kinase D Activation and Phosphorylation Induced by Lysophosphatidic Acid

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    To examine the contribution of different G-protein pathways to lysophosphatidic acid (LPA)-induced protein kinase D (PKD) activation, we tested the effect of LPA on PKD activity in murine embryonic cell lines deficient in Galpha q/11 (Galpha q/11 KO cells) or Galpha 12/13 (Galpha 12/13 KO cells) and used cells lacking rhodopsin kinase (RK cells) as a control. In RK and Galpha 12/13 KO cells, LPA induced PKD activation through a phospholipase C/protein kinase C pathway in a concentration-dependent fashion with maximal stimulation (6-fold for RK cells and 4-fold for Galpha 12/13 KO cells in autophosphorylation activity) achieved at 3 µM. In contrast, LPA did not induce any significant increase in PKD activity in Galpha q/11 KO cells. However, LPA induced a significantly increased PKD activity when Galpha q/11 KO cells were transfected with Galpha q. LPA-induced PKD activation was modestly attenuated by prior exposure of RK cells to pertussis toxin (PTx) but abolished by the combination treatments of PTx and Clostridium difficile toxin B. Surprisingly, PTx alone strikingly inhibited LPA-induced PKD activation in a concentration-dependent fashion in Galpha 12/13 KO cells. Similar results were obtained when activation loop phosphorylation at Ser-744 was determined using an antibody that detects the phosphorylated state of this residue. Our results indicate that Gq is necessary but not sufficient to mediate LPA-induced PKD activation. In addition to Gq, LPA requires additional G-protein pathways to elicit a maximal response with Gi playing a critical role in Galpha 12/13 KO cells. We conclude that LPA induces PKD activation through Gq, Gi, and G12 and propose that PKD activation is a point of convergence in the action of multiple G-protein pathways

    Interaction of Gα₁₂ with Gα₁₃ and Gα_q signaling pathways

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    The G(12) subfamily of heterotrimeric G-proteins consists of two members, G(12) and G(13). Gene-targeting studies have revealed a role for G(13) in blood vessel development. Mice lacking the a subunit of G(13) die around embryonic day 10 as the result of an angiogenic defect. On the other hand, the physiological role of G(12) is still unclear. To address this issue, we generated Galpha(12)-deficient mice. In contrast to the Galpha(13)-deficient mice, Galpha(12)-deficient mice are viable, fertile, and do not show apparent abnormalities. However, Galpha(12) does not seem to be entirely redundant, because in the offspring generated from Galpha(12)+/-Galpha(13) intercrosses, at least one intact Galpha(12) allele is required for the survival of animals with only one Galpha(13) allele. In addition, Galpha(12) and Galpha(13) showed a difference in mediating cell migratory response to lysophosphatidic acid in embryonic fibroblast cells. Furthermore, mice lacking both Galpha(12) and Galpha(q) die in utero at about embryonic day 13. These data indicate that the Galpha(12)-mediated signaling pathway functionally interacts not only with the Galpha(13)- but also with the Galpha(q/11)-mediated signaling systems

    Every Step Counts: Adapting Qualtrics to Encourage Student Engagement in Library Orientations

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    Many libraries have adopted gamification strategies to enhance their orientation programmes, in the hope of encouraging better student engagement via goal-based design. A literature review reveals a lack of in-depth, granular data on participant behavior in these gamified activities, with evidence generally limited to post-event feedback and comments. Such data could potentially provide insights to help assess the extent to which orientation programme outcomes have been achieved. An example of an orientation activity with in-depth usage data is provided by Hong Kong Baptist University Library’s paperless, mobile-assisted Library Mystery Challenge (the Challenge). Designed using the popular data collection and analysis platform Qualtrics, the Challenge is presented to students as a scenario where they are tasked with helping the Library to find a missing student. Participants are given a series of clues that lead them to various locations, and at each stop they are provided with information on the nearby facilities and services. The Challenge has been run three times since Fall 2016, with close to 100% positive feedback from participants. Game design using Qualtrics is cost-effective, customizable and scalable, and has required minimal staffing resources. The authors will present the design principles of the Challenge, with a particular emphasis on how librarians analyzed student data recorded at each step of completion in the Challenge, for example, participation and retention, average time to completion, etc., and how these insights into student behavior were used to refine the user experience in subsequent iterations of the Challenge. Practical suggestions and advice for making informed decisions through the use of data analytics tools will also be shared

    Does mobile phone ownership predict better utilization of maternal and newborn health services? a cross-sectional study in Timor-Leste.

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    BackgroundIncreasingly popular mobile health (mHealth) programs have been proposed to promote better utilization of maternal, newborn and child health services. However, women who lack access to a mobile phone are often left out of both mHealth programs and research. In this study, we determine whether household mobile phone ownership is an independent predictor of utilization of maternal and newborn health services in Timor-Leste.MethodsThe study included 581 women aged 15-49 years with a child under the age of two years from the districts of Manufahi and Ainaro in Timor-Leste. Participants were interviewed via a structured survey of knowledge, practices, and coverage of maternal and child health services, with additional questions related to ownership and utilization of mobile phones. Mobile phone ownership was the exposure variable, and the dependent variables included having at least four antenatal care visits, skilled birth attendance, health facility delivery, a postnatal checkup within 24 h, and a neonatal checkup within 24 h for their youngest child. Logistic regression models were applied to assess for associations.ResultsSixty-seven percent of women reported having at least one mobile phone in the family. Women who had a mobile phone were significantly more likely to be of higher socioeconomic status and to utilize maternal and newborn health services. However, after adjusting socioeconomic factors, household mobile phone ownership was not independently associated with any of the dependent variables.ConclusionEvaluations of the effects of mHealth programs on health in a population need to consider the likelihood of socioeconomic differentials indicated by mobile phone ownership

    Treatment of Liver Metastases in Patients with Neuroendocrine Tumors of Gastroesophageal and Pancreatic Origin

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    Well-to-moderately differentiated neuroendocrine tumors of gastroesophageal and pancreatic origin (GEP-NETs) with liver metastasis are a heterogeneous group of malignancies for which a range of therapeutic options have been employed. Surgical resection of hepatic metastases or hepatic artery embolization may be beneficial in patients with hepatic-predominant metastatic disease. Patients with “carcinoid” syndrome and syndromes associated with functional pancreatic NET (PNET) can be effectively treated with somatostatin analogs. On the other hand, the efficacy of systemic chemotherapy for these patients is limited. A placebo-controlled, double-blind, prospective, and randomized study showed that octreotide LAR improves progression-free survival in patients with advanced midgut functional “carcinoids.” In patients with advanced pancreatic NET, randomized, placebo-controlled studies have recently demonstrated that treatment with the tyrosine kinase inhibitor sunitinib or with mTOR inhibitor everolimus is associated with improved progression-free survival. Based on these studies, octreotide LAR, sunitinib, or everolimus are now considered as first-line therapeutic options in patients with advanced NET. Future studies will likely further define the role of these agents in patients with carcinoid liver metastasis and pancreatic NET liver metastasis

    A Novel Treatment of Postpartum Depression and Review of Literature.

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    Early-onset postpartum depression has been shown to have a unique neurobiological basis compared to major depressive disorder, implying a need for targeted treatments such as the recent Food and Drug Administration (FDA)-approved brexanolone. In this case report, a woman with a past medical history of major depressive disorder was diagnosed with postpartum depression due to worsening mood with suicidal and homicidal ideations. She was treated with vilazodone and aripiprazole with good effect after consideration of her past medication trials. Her regimen is unique in clinical practice and not reported in current literature for the treatment of postpartum depression. It may represent a safe and effective medication choice, especially in the context of current first-line treatments that have a high treatment failure rate. More research is needed to find treatments that address the unique challenges of postpartum women

    Dynamic GATA4 enhancers shape the chromatin landscape central to heart development and disease.

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    How stage-specific enhancer dynamics modulate gene expression patterns essential for organ development, homeostasis and disease is not well understood. Here, we addressed this question by mapping chromatin occupancy of GATA4--a master cardiac transcription factor--in heart development and disease. We find that GATA4 binds and participates in establishing active chromatin regions by stimulating H3K27ac deposition, which facilitates GATA4-driven gene expression. GATA4 chromatin occupancy changes markedly between fetal and adult heart, with a limited binding sites overlap. Cardiac stress restored GATA4 occupancy to a subset of fetal sites, but many stress-associated GATA4 binding sites localized to loci not occupied by GATA4 during normal heart development. Collectively, our data show that dynamic, context-specific transcription factors occupancy underlies stage-specific events in development, homeostasis and disease

    Direct genetic demonstration of Gα13 coupling to the orphan G protein-coupled receptor G2A leading to RhoA-dependent actin rearrangement

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    G2A is an orphan G protein-coupled receptor (GPCR), expressed predominantly in T and B cells and homologous to a small group of GPCRs of unknown function expressed in lymphoid tissues. G2A is transcriptionally induced in response to diverse stimuli, and its ectopic expression suppresses transformation of B lymphoid precursors by BCR-ABL. G2A induces morphological transformation of NIH 3T3 fibroblasts. Microinjection of constructs encoding G2A into Swiss 3T3 fibroblasts induces actin reorganization into stress fibers that depends on RhoA, but not CDC42 or RAC. G2A elicits RhoA-dependent transcriptional activation of serum response factor. Direct evaluation of RhoA activity demonstrates elevated levels of RhoA-GTP in G2A-expressing cells. Microinjection of embryonic fibroblasts derived from various Galpha knockout mice establishes a requirement for Galpha 13 but not Galpha 12 or Galpha q/11 in G2A-induced actin rearrangement. In conclusion, G2A represents a family of GPCRs expressed in lymphocytes that may link diverse stimuli to cytoskeletal reorganization and transcriptional activation through a pathway involving Galpha 13 and RhoA

    HIV risks and prevention: themes from a community forum among African community members in Queensland

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    Introduction: Significant health disparities persist regarding new/late HIV diagnoses among HIV sub-Saharan African communities in Australia . A wide range of personal and cultural beliefs and practices significantly influence HIV risk and prevention both within Australia and during return visits to countries of origin. Method: A community forum was conducted which included 23 male and female adult members of African community agencies/networks and stakeholders. The forum was facilitated by cultural workers and an experienced clinician/researcher. The forum consisted of small and large group discussions regardingkey topics with responses transcribed verbatim. Thematic analysis was utilised to analyse data collected at the forum. Ethics approval was obtained. Results: Issues of stigma and denial, social norms, tradition and culture permeated perceptions and beliefs regarding HIV prevention and transmission among African Australians, particularly in relation to return travel to countries of origin. Conclusions: The role of international travel as a risk factor for HIV acquisition requires increased examination and review, as do the role of the GP and Pre-exposure prophylaxis (PrEP) as responses to that risk. Further assessment of PrEP as an appropriate and feasible intervention within the community is needed with careful attention given to negative community perceptions and its potential impact on individuals
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