591 research outputs found

    Fluid Mechanics of Everyday Objects

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    High speed Schlieren videos were produced highlighting the fluid mechanics found in everyday objects. This video (entry 102369) was submitted as part of the Gallery of Fluid Motion 2013, which is a showcase of fluid dynamics videos.Comment: Both a high-resolution version and a low-resolution version of the submitted video are available for downloa

    East Asia and the global/transatlantic/Western crisis

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    This paper introduces the special collection on East Asia and the Global Crisis. After justifying why a focus on East Asia is appropriate, it draws out the main themes that run through the individual contributions. These are the extent to which the region is decoupling from the global economy (or the West), the increasing legitimacy of statist alternatives to neoliberal development strategies, and the impact of crises on the definition of ―region‖ and the functioning of regional institutions and governance mechanisms

    Immune Cell–Derived C3 Is Required for Autoimmune Diabetes Induced by Multiple Low Doses of Streptozotocin

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    OBJECTIVE: The complement system contributes to autoimmune injury, but its involvement in promoting the development of autoimmune diabetes is unknown. In this study, our goal was to ascertain the role of complement C3 in autoimmune diabetes. RESEARCH DESIGN AND METHODS: Susceptibility to diabetes development after multiple low-dose streptozotocin treatment in wild-type (WT) and C3-deficient mice was analyzed. Bone marrow chimeras, luminex, and quantitative reverse transcription PCR assays were performed to evaluate the phenotypic and immunologic impact of C3 in the development of this diabetes model. RESULTS: Coincident with the induced elevations in blood glucose levels, we documented alternative pathway complement component gene expression within the islets of the diabetic WT mice. When we repeated the experiments with C3-deficient mice, we observed complete resistance to disease, as assessed by the absence of histologic insulitis and the absence of T-cell reactivity to islet antigens. Studies of WT chimeras bearing C3-deficient bone marrow cells showed that bone marrow cell-derived C3, and not serum C3, is involved in the induction of diabetes in this model. CONCLUSIONS: The data reveal a key role for immune cell-derived C3 in the pathogenesis of murine multiple low-dose streptozotocin-induced diabetes and support the concept that immune cell mediated diabetes is in part complement-dependen

    Role of the Mitochondria in Immune-Mediated Apoptotic Death of the Human Pancreatic β Cell Line βLox5

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    Mitochondria are indispensable in the life and death of many types of eukaryotic cells. In pancreatic beta cells, mitochondria play an essential role in the secretion of insulin, a hormone that regulates blood glucose levels. Unregulated blood glucose is a hallmark symptom of diabetes. The onset of Type 1 diabetes is preceded by autoimmune-mediated destruction of beta cells. However, the exact role of mitochondria has not been assessed in beta cell death. In this study, we examine the role of mitochondria in both Fas- and proinflammatory cytokine-mediated destruction of the human beta cell line, βLox5. IFNγ primed βLox5 cells for apoptosis by elevating cell surface Fas. Consequently, βLox5 cells were killed by caspase-dependent apoptosis by agonistic activation of Fas, but only after priming with IFNγ. This beta cell line undergoes both apoptotic and necrotic cell death after incubation with the combination of the proinflammatory cytokines IFNγ and TNFα. Additionally, both caspase-dependent and -independent mechanisms that require proper mitochondrial function are involved. Mitochondrial contributions to βLox5 cell death were analyzed using mitochondrial DNA (mtDNA) depleted βLox5 cells, or βLox5 ρ0 cells. βLox5 ρ0 cells are not sensitive to IFNγ and TNFα killing, indicating a direct role for the mitochondria in cytokine-induced cell death of the parental cell line. However, βLox5 ρ0 cells are susceptible to Fas killing, implicating caspase-dependent extrinsic apoptotic death is the mechanism by which these human beta cells die after Fas ligation. These data support the hypothesis that immune mediators kill βLox5 cells by both mitochondrial-dependent intrinsic and caspase-dependent extrinsic pathways

    MicroRNAs in pulmonary arterial remodeling

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    Pulmonary arterial remodeling is a presently irreversible pathologic hallmark of pulmonary arterial hypertension (PAH). This complex disease involves pathogenic dysregulation of all cell types within the small pulmonary arteries contributing to vascular remodeling leading to intimal lesions, resulting in elevated pulmonary vascular resistance and right heart dysfunction. Mutations within the bone morphogenetic protein receptor 2 gene, leading to dysregulated proliferation of pulmonary artery smooth muscle cells, have been identified as being responsible for heritable PAH. Indeed, the disease is characterized by excessive cellular proliferation and resistance to apoptosis of smooth muscle and endothelial cells. Significant gene dysregulation at the transcriptional and signaling level has been identified. MicroRNAs are small non-coding RNA molecules that negatively regulate gene expression and have the ability to target numerous genes, therefore potentially controlling a host of gene regulatory and signaling pathways. The major role of miRNAs in pulmonary arterial remodeling is still relatively unknown although research data is emerging apace. Modulation of miRNAs represents a possible therapeutic target for altering the remodeling phenotype in the pulmonary vasculature. This review will focus on the role of miRNAs in regulating smooth muscle and endothelial cell phenotypes and their influence on pulmonary remodeling in the setting of PAH

    Different perceptions of the burden of upper GI endoscopy: an empirical study in three patient groups

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    Background: Few studies have evaluated patients' perceived burden of cancer surveillance tests. Cancer screening and surveillance, however, require a large number of patients to undergo potentially burdensome tests with only some experiencing health gains from it. We investigated the determinants of patients' reported burden of upper gastrointestinal (GI) endoscopy by comparing data from three patient groups. Patients and methods: A total of 476 patients were included: 180 patients under regular surveillance for Barrett esophagus (BE), a premalignant disorder; 214 patients with non-specific upper GI symptoms (NS), and 82 patients recently diagnosed with upper GI cancer (CA). We assessed pain, discomfort and overall burden experienced during endoscopy, symptoms in the week afterwards and psychological distress over time (Hospital Anxiety and Depression scale and Impact of Event Scale). Results: Two-thirds (66%) of patients reported discomfort and overall burden of upper GI endoscopy. Only 23% reported any pain. BE patients reported significantly less discomfort, pain and overall burden than the other patients: those with NS reported more discomfort, CA patients more pain, and both more overall burden. These differences could be statistically explained by the number of previous endoscopies and whether sedation was provided or not, but not by patient characteristics. Conclusion: The perception of upper GI endoscopy varies by patient group, due to potential adaptation after multiple endoscopies and aspects of th

    Evidence that Proteasome-Dependent Degradation of the Retinoblastoma Protein in Cells Lacking A-Type Lamins Occurs Independently of Gankyrin and MDM2

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    A-type lamins, predominantly lamins A and C, are nuclear intermediate filaments believed to act as scaffolds for assembly of transcription factors. Lamin A/C is necessary for the retinoblastoma protein (pRB) stabilization through unknown mechanism(s). Two oncoproteins, gankyrin and MDM2, are known to promote pRB degradation in other contexts. Consequently, we tested the hypothesis that gankyrin and/or MDM2 are required for enhanced pRB degradation in Lmna-/- fibroblasts. Principal Findings. To determine if gankyrin promotes pRB destabilization in the absence of lamin A/C, we first analyzed its protein levels in Lmna-/- fibroblasts. Both gankyrin mRNA levels and protein levels are increased in these cells, leading us to further investigate its role in pRB degradation. Consistent with prior reports, overexpression of gankyrin in Lmna+/+ cells destabilizes pRB. This decrease is functionally significant, since gankyrin overexpressing cells are resistant to p16(ink4a)-mediated cell cycle arrest. These findings suggest that lamin A-mediated degradation of pRB would be gankyrin-dependent. However, effective RNAi-enforced reduction of gankyrin expression in Lmna-/- cells was insufficient to restore pRB stability. To test the importance of MDM2, we disrupted the MDM2-pRB interaction by transfecting Lmna-/- cells with p14(arf). p14(arf) expression was also insufficient to stabilize pRB or confer cell cycle arrest, suggesting that MDM2 also does not mediate pRB degradation in Lmna-/- cells.Our findings suggest that pRB degradation in Lmna-/- cells occurs by gankyrin and MDM2-independent mechanisms, leading us to propose the existence of a third proteasome-dependent pathway for pRB degradation. Two findings from this study also increase the likelihood that lamin A/C functions as a tumor suppressor. First, protein levels of the oncoprotein gankyrin are elevated in Lmna-/- fibroblasts. Second, Lmna-/- cells are refractory to p14(arf)-mediated cell cycle arrest, as was previously shown with p16(ink4a). Potential roles of lamin A/C in the suppression of tumorigenesis are discussed

    Lifespan benefits for the combination of rapamycin plus acarbose and for captopril in genetically heterogeneous mice.

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    Mice bred in 2017 and entered into the C2017 cohort were tested for possible lifespan benefits of (R/S)-1,3-butanediol (BD), captopril (Capt), leucine (Leu), the Nrf2-activating botanical mixture PB125, sulindac, syringaresinol, or the combination of rapamycin and acarbose started at 9 or 16 months of age (RaAc9, RaAc16). In male mice, the combination of Rapa and Aca started at 9 months and led to a longer lifespan than in either of the two prior cohorts of mice treated with Rapa only, suggesting that this drug combination was more potent than either of its components used alone. In females, lifespan in mice receiving both drugs was neither higher nor lower than that seen previously in Rapa only, perhaps reflecting the limited survival benefits seen in prior cohorts of females receiving Aca alone. Capt led to a significant, though small (4% or 5%), increase in female lifespan. Capt also showed some possible benefits in male mice, but the interpretation was complicated by the unusually low survival of controls at one of the three test sites. BD seemed to produce a small (2%) increase in females, but only if the analysis included data from the site with unusually short-lived controls. None of the other 4 tested agents led to any lifespan benefit. The C2017 ITP dataset shows that combinations of anti-aging drugs may have effects that surpass the benefits produced by either drug used alone, and that additional studies of captopril, over a wider range of doses, are likely to be rewarding
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