208 research outputs found

    Ca2+-induced changes in energy metabolism and viability of melanoma cells

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    Cancer cells are characterized by a high rate of glycolysis, which is their primary energy source. We show here that a rise in intracellular-free calcium ion (Ca2+), induced by Ca2+-ionophore A23187, exerted a deleterious effect on glycolysis and viability of B16 melanoma cells. Ca2+-ionophore caused a dose-dependent detachment of phosphofructokinase (EC 2.7.1.11), one of the key enzymes of glycolysis, from cytoskeleton. It also induced a decrease in the levels of glucose 1,6-bisphosphate and fructose 1,6-bisphosphate, the two stimulatory signal molecules of glycolysis. All these changes occurred at lower concentrations of the drug than those required to induce a reduction in viability of melanoma cells. We also found that low concentrations of Ca2+-ionophore induced an increase in adenosine 5′-triphosphate (ATP), which most probably resulted from the increase in mitochondrial-bound hexokinase, which reflects a defence mechanism. This mechanism can no longer operate at high concentrations of the Ca2+-ionophore, which causes a decrease in mitochondrial and cytosolic hexokinase, leading to a drastic fall in ATP and melanoma cell death. The present results suggest that drugs which are capable of inducing accumulation of intracellular-free Ca2+ in melanoma cells would cause a reduction in energy-producing systems, leading to melanoma cell death. © 1999 Cancer Research Campaig

    Flipping the world upside down: Using eye tracking in virtual reality to study visual search in inverted scenes

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    Image inversion is a powerful tool for investigating cognitive mechanisms of visual perception. However, studies have mainly used inversion in paradigms presented on two-dimensional computer screens. It remains open whether disruptive effects of inversion also hold true in more naturalistic scenarios. In our study, we used scene inversion in virtual reality in combination with eye tracking to investigate the mechanisms of repeated visual search through three-dimensional immersive indoor scenes. Scene inversion affected all gaze and head measures except fixation durations and saccade amplitudes. Our behavioral results, surprisingly, did not entirely follow as hypothesized: While search efficiency dropped significantly in inverted scenes, participants did not utilize more memory as measured by search time slopes. This indicates that despite the disruption, participants did not try to compensate the increased difficulty by using more memory. Our study highlights the importance of investigating classical experimental paradigms in more naturalistic scenarios to advance research on daily human behavior

    Atomically thin quantum light-emitting diodes

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    This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The data that support the findings of this study are available from the corresponding authors upon request.Transition metal dichalcogenides are optically active, layered materials promising for fast optoelectronics and on-chip photonics. We demonstrate electrically driven single-photon emission from localized sites in tungsten diselenide and tungsten disulphide. To achieve this, we fabricate a light-emitting diode structure comprising single-layer graphene, thin hexagonal boron nitride and transition metal dichalcogenide mono- and bi-layers. Photon correlation measurements are used to confirm the single-photon nature of the spectrally sharp emission. These results present the transition metal dichalcogenide family as a platform for hybrid, broadband, atomically precise quantum photonics devices.European UnionEuropean Research Council (ERC)Engineering and Physical Sciences Research Council (EPSRC

    Atomically thin quantum light-emitting diodes

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    Transition metal dichalcogenides are optically active, layered materials promising for fast optoelectronics and on-chip photonics. We demonstrate electrically driven single-photon emission from localized sites in tungsten diselenide and tungsten disulphide. To achieve this, we fabricate a light-emitting diode structure comprising single-layer graphene, thin hexagonal boron nitride and transition metal dichalcogenide mono- and bi-layers. Photon correlation measurements are used to confirm the single-photon nature of the spectrally sharp emission. These results present the transition metal dichalcogenide family as a platform for hybrid, broadband, atomically precise quantum photonics devices.European Research Council (Grant ID: PHOENICS), Engineering and Physical Sciences Research Council (Grant ID: EP/N010345/1

    Renal outcomes of agalsidase beta treatment for Fabry disease: role of proteinuria and timing of treatment initiation

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    BACKGROUND: The purpose of this study was to identify determinants of renal disease progression in adults with Fabry disease during treatment with agalsidase beta. METHODS: Renal function was evaluated in 151 men and 62 women from the Fabry Registry who received agalsidase beta at an average dose of 1 mg/kg/2 weeks for at least 2 years. Patients were categorized into quartiles based on slopes of estimated glomerular filtration rate (eGFR) during treatment. Multivariate logistic regression analyses were used to identify factors associated with renal disease progression. RESULTS: Men within the first quartile had a mean eGFR slope of -0.1 mL/min/1.73m(2)/year, whereas men with the most rapid renal disease progression (Quartile 4) had a mean eGFR slope of -6.7 mL/min/1.73m(2)/year. The risk factor most strongly associated with renal disease progression was averaged urinary protein:creatinine ratio (UP/Cr) ≥1 g/g (odds ratio 112, 95% confidence interval (95% CI) 4-3109, P = 0.0054). Longer time from symptom onset to treatment was also associated with renal disease progression (odds ratio 19, 95% CI 2-184, P = 0.0098). Women in Quartile 4 had the highest averaged UP/Cr (mean 1.8 g/g) and the most rapid renal disease progression: (mean slope -4.4 mL/min/1.73m(2)/year). CONCLUSIONS: Adults with Fabry disease are at risk for progressive loss of eGFR despite enzyme replacement therapy, particularly if proteinuria is ≥1 g/g. Men with little urinary protein excretion and those who began receiving agalsidase beta sooner after the onset of symptoms had stable renal function. These findings suggest that early intervention may lead to optimal renal outcomes

    Agalsidase beta treatment is associated with improved quality of life in patients with Fabry disease: Findings from the Fabry Registry

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    Purpose: To evaluate the effect of agalsidase beta on longitudinal health-related quality of life in patients with Fabry disease. Methods: the SF-36 (R) Health Survey was used to measure health-related quality of life in Fabry Registry patients. Seventy-one men and 59 women who were treated with agalsidase beta (median dose: 1.0 mg/kg/2 weeks) and who had baseline and at least 2 yearly posttreatment health-related quality of life measurements were included in these analyses. A repeated measures model was used to analyze change in score from baseline. Results: Men improved in the physical component summary and in all eight scales of the SF-36 after 1 and 2 years and in the mental component summary after 1 year of agalsidase beta treatment (P < 0.05). Women improved in the mental component summary and in six of the eight scales after 1 and/or 2 years of treatment. Patients whose baseline SF-36 scores were below the median showed the greatest improvements. These responses were comparable with or greater than the published effects of various treatments for multiple sclerosis, rheumatoid arthritis, central neuropathic pain, and Gaucher disease. Conclusion: Long-term treatment with agalsidase beta resulted in substantial improvements in health-related quality of life in both men and women; the effect was more pronounced in men. Genet Med 2010:12(11):703 712.Genzyme CorporationGenzymeNatl Univ Hosp, Dept Endocrinol, DK-2100 Copenhagen, DenmarkSan Bassano Hosp, Dept Neurol, Bassano Del Grappa, ItalyUniv Padua, Dept Neurosci, Padua, ItalyUniv Wurzburg, Dept Med, Wurzburg, GermanyColumbia Univ, Dept Pediat, Div Clin Genet, Coll Phys & Surg, New York, NY 10027 USACincinnati Childrens Hosp, Div Human Genet, Cincinnati, OH USAUniversidade Federal de São Paulo, Inatos Metab CREIM, São Paulo, BrazilMassachusetts Gen Hosp, Dept Neurol, Boston, MA 02114 USAGenzyme Corp, Dept Biomed Data Sci & Informat, Cambridge, MA USAUniversidade Federal de São Paulo, Inatos Metab CREIM, São Paulo, BrazilWeb of Scienc

    A many-analysts approach to the relation between religiosity and well-being

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    The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N = 10, 535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported beta = 0.120). For the second research question, this was the case for 65% of the teams (median reported beta = 0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates.</p

    Differential responses to doxorubicin-induced phosphorylation and activation of Akt in human breast cancer cells

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    INTRODUCTION: We have shown previously that overexpression of constitutively active Akt or activation of Akt caused by constitutively active Ras or human epidermal growth factor receptor-2 (HER2) confers on breast cancer cells resistance to chemotherapy or radiotherapy. As an expanded study we here report differential responses in terms of phosphorylation and activation of Akt as a result of treatment with doxorubicin in a panel of breast cancer cell lines. METHODS: The levels of Akt phosphorylation and activity were measured by Western blot analysis with an anti-Ser473-phosphorylated Akt antibody and by in vitro Akt kinase assay using glycogen synthase kinase-3 as a substrate. RESULTS: Within 24 hours after exposure to doxorubicin, MCF7, MDA468 and T47D cells showed a drug-dose-dependent increase in the levels of phosphorylated Akt; in contrast, SKBR3 and MDA231 cells showed a decrease in the levels of phosphorylated Akt, and minimal or no changes were detected in MDA361, MDA157 and BT474 cells. The doxorubicin-induced Akt phosphorylation was correlated with increased kinase activity and was dependent on phosphoinositide 3-kinase (PI3-K). An increased baseline level of Akt was also found in MCF7 cells treated with ionizing radiation. The cellular responses to doxorubicin-induced Akt phosphorylation were potentiated after the expression of Akt upstream activators including HER2, HER3 and focal adhesion kinase. CONCLUSION: Taken together with our recent published results showing that constitutive Akt mediates resistance to chemotherapy or radiotherapy, our present data suggest that the doxorubicin-induced phosphorylation and activation of Akt might reflect a cellular defensive mechanism of cancer cells to overcome doxorubicin-induced cytotoxic effects, which further supports the current efforts of targeting PI3-K/Akt for enhancing the therapeutic responses of breast cancer cells to chemotherapy and radiotherapy
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