2,179 research outputs found
Inactivation of SAG E3 Ubiquitin Ligase Blocks Embryonic Stem Cell Differentiation and Sensitizes Leukemia Cells to Retinoid Acid
Sensitive to Apoptosis Gene (SAG), also known as RBX2 (RING box protein-2), is the RING component of SCF (SKP1, Cullin, and F-box protein) E3 ubiquitin ligase. Our previous studies have demonstrated that SAG is an anti-apoptotic protein and an attractive anti-cancer target. We also found recently that Sag knockout sensitized mouse embryonic stem cells (mES) to radiation and blocked mES cells to undergo endothelial differentiation. Here, we reported that compared to wild-type mES cells, the Sag−/− mES cells were much more sensitive to all-trans retinoic acid (RA)-induced suppression of cell proliferation and survival. While wild-type mES cells underwent differentiation upon exposure to RA, Sag−/− mES cells were induced to death via apoptosis instead. The cell fate change, reflected by cellular stiffness, can be detected as early as 12 hrs post RA exposure by AFM (Atomic Force Microscopy). We then extended this novel finding to RA differentiation therapy of leukemia, in which the resistance often develops, by testing our hypothesis that SAG inhibition would sensitize leukemia to RA. Indeed, we found a direct correlation between SAG overexpression and RA resistance in multiple leukemia lines. By using MLN4924, a small molecule inhibitor of NEDD8-Activating Enzyme (NAE), that inactivates SAG-SCF E3 ligase by blocking cullin neddylation, we were able to sensitize two otherwise resistant leukemia cell lines, HL-60 and KG-1 to RA. Mechanistically, RA sensitization by MLN4924 was mediated via enhanced apoptosis, likely through accumulation of pro-apoptotic proteins NOXA and c-JUN, two well-known substrates of SAG-SCF E3 ligase. Taken together, our study provides the proof-of-concept evidence for effective treatment of leukemia patients by RA-MLN4924 combination
Causal analysis between altered levels of interleukins and obstructive sleep apnea
BackgroundInflammation proteins including interleukins (ILs) have been reported to be related to obstructive sleep apnea (OSA). The aims of this study were to estimate the levels for several key interleukins in OSA and the causal effects between them.MethodWeighted mean difference (WMD) was used to compare the expression differences of interleukins between OSA and control, and the changed levels during OSA treatments in the meta-analysis section. A two-sample Mendelian randomization (MR) was used to estimate the causal directions and effect sizes between OSA risks and interleukins. The inverse-variance weighting (IVW) was used as the primary method followed by several other MR methods including MR Egger, Weighted median, and MR-Robust Adjusted Profile Score as sensitivity analysis.ResultsNine different interleukins—IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17, IL-18, and IL-23—were elevated in OSA compared with control to varying degrees, ranging from 0.82 to 100.14 pg/ml, and one interleukin, IL-10, was decreased by 0.77 pg/ml. Increased IL-1β, IL-6, and IL-8 rather than IL-10 can be reduced in OSA by effective treatments. Further, the MR analysis of the IVW method showed that there was no significant evidence to support the causal relationships between OSA and the nine interleukins—IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17, and IL-18. Among them, the causal effect of OSA on IL-5 was almost significant [estimate: 0.267 (−0.030, 0.564), p = 0.078]. These results were consistent in the sensitivity analysis.ConclusionsAlthough IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IL-17, IL-18, and IL-23 were increasing and IL-10 was reducing in OSA, no significant causal relationships were observed between them by MR analysis. Further research is needed to test the causality of OSA risk on elevated IL-5 level
Analisis in silico peptida berasaskan epitop daripada protein-protein imunogen Burkholderia pseudomallei
Melioidosis is an infectious disease caused by the gram-negative bacterium Burkholderia pseudomallei. This disease is associated with high human mortality rate, especially in tropical and subtropical regions. Rapid diagnosis is crucial in ensuring proper management and treatment of the disease with effective antibiotics. Currently, melioidosis diagnosis, bacterial culture is time consuming, difficult, and not sensitive, while IHA is hindered by high antibody background in healthy population and ELISA lacks standardization and is hindered by antigen inconsistency. To improve the current diagnosis method for melioidosis, this research aims to identify, screen, and develop epitope-spanning peptides to be used as standardized B. pseudomallei antigen in serodiagnosis of melioidosis. Peptides are favoured as they are more stable, and they offer effective and rapid antibody detection. Using in silico analysis, a pool of 154 B. pseudomallei proteins previously reported as immunogenic were screened and ranked based on their antigenicity, subcellular localization, stability, adhesive properties, and ability to interact with class I and class II major histocompatibility complex (MHC). The selected candidate from the analysis, BPSS0908 and BPSL2152 were then taken for further analysis to identify linear B-cell epitopes using several sequence-based B-cell epitope prediction tools. Consensus sequences that are confidently predicted by more than two prediction tools and are longer than 15 amino acids were then selected as linear B-cell epitopes. Through ELISA analysis, low sensitivity was demonstrated by the epitope-spanning peptides as compared to B. pseudomallei crude lysate. However, high specificity of 100% was observed for all tested peptides. The low sensitivity demonstrated by the peptides in ELISA could be due to lack of 3-dimensional structure which is needed for a stable antigen-antibody binding
Investigation of the phase formation and dielectric properties of Bi7Ta3O18
Polycrystalline Bi7Ta3O18 was synthesised at the firing temperature of 950 °C over 18 h via conventional solid state method. It crystallised in a monoclinic system with space group C2/m, Z = 4 similar to that reported diffraction pattern in the Inorganic Crystal Structure Database (ICSD), 1-89-6647. The refined lattice parameters were a = 34.060 (3) Å, b = 7.618 (9) Å, c = 6.647 (6) Å with α = γ = 90° and β = 109.210 (7), respectively. The intermediate phase was predominantly in high-symmetry cubic structure below 800 °C and finally evolved into a low-symmetry monoclinic structured, Bi7Ta3O18 at 950 °C. The sample contained grains of various shapes with different orientations in the size ranging from 0.33–22.70 μm. The elemental analysis showed the sample had correct stoichiometry with negligible Bi2O3 loss. Bi7Ta3O18 was thermally stable and it exhibited a relatively high relative permittivity, 241 and low dielectric loss, 0.004 at room temperature, ∼30 °C and frequency of 1 MHz
Prediction of the Lymph Node Status in Patients with Intrahepatic Cholangiocarcinoma: Analysis of 320 Surgical Cases
Purpose: This study was conducted to identify factors involved in lymph node metastasis (LNM) and evaluate their role in predicting LNM in clinically lymph node negative (clinical stage I–III) intrahepatic cholangiocarcinoma (ICC). Materials and Methods: We selected 320 patients who were diagnosed with ICC with no apparent clinical LNM (T1–3N0M0). Age, gender, tumor boundary, histological differentiation, tumor size, and carbohydrate antigen 19-9 value were the studied factors. Univariate and multivariate logistic analysis were conducted. Receiver operating characteristics curve analysis was used to test the predicting value of each factor and a test which combined the associated factors was used to predict LNM. Results: LNM was observed in 76 cases (76/320, 23.8%). Univariate and multivariate analysis showed that histological differentiation as well as tumor boundary and tumor size significantly correlated with LNM. The sensitivity and negative predictive value for LNM for the three factors when combined was 96.1 and 95% respectively. This means that 5% of the patients who did not have the risk factors mentioned above developed LNM. Conclusion: This model used the combination of three factors (low-graded histological differentiation, distinct tumor boundary, small tumor size) and they proved to be useful in predicting LNM in ICC with clinically lymph node negative cases. In patients with these criteria, lymph node dissection or lymph node irradiation may be omitted and such cases may also be good candidates for stereotactic body radiotherapy (SBRT)
Context-specific economic evaluation for molecular pathology tests: An application in colorectal cancer in the West of Scotland.
The cost-effectiveness of molecular pathology testing is highly context dependent. The field is fast-moving, and national health technology assessment may not be relevant or timely for local decision makers. This study illustrates a method of context-specific economic evaluation that can be carried out in a limited timescale without extensive resources. We established a multi-disciplinary group including an oncologist, pathologists and a health economist. We set out diagnostic and treatment pathways and costs using registry data, health technology assessments, guidelines, audit data, and estimates from the group. Sensitivity analysis varied input parameters across plausible ranges. The evaluation setting was the West of Scotland and UK NHS perspective was adopted. The evaluation was assessed against the AdHopHTA checklist for hospital-based health technology assessment. A context-specific economic evaluation could be carried out on a timely basis using limited resources. The evaluation met all relevant criteria in the AdHopHTA checklist. Health outcomes were expected to be at least equal to the current strategy. Annual cost savings of £637,000 were estimated resulting primarily from a reduction in the proportion of patients receiving intravenous infusional chemotherapy regimens. The result was not sensitive to any parameter. The data driving the main cost saving came from a small clinical audit. We recommended this finding was confirmed in a larger population. The method could be used to evaluate testing changes elsewhere. The results of the case study may be transferable to other jurisdictions where the organization of cancer services is fragmented
Synthesis, structural and electrical properties of novel pyrochlores in the Bi2O3-CuO-Ta2O5 ternary system
A series of non-stoichiometric cubic pyrochlores with general formula, Bi3−xCu1.8Ta3+xO13.8+x (BCT) was successfully prepared by solid state reaction at the firing temperature of 950 °C over 2 days. The solid solution mechanism is proposed as one-to-one replacement of Bi3+ for Ta5+, together with a variation in oxygen content in order to achieve electroneutrality. The solid solution limit is confirmed by X-ray diffraction technique (XRD) for which linear variation of lattice constants is observed at 0 ≤ x ≤ 0.6. The refined lattice constants are found to be in the range of 10.4838 (8) Å–10.5184 (4) Å and the grain sizes of these samples determined by scanning electron microscopy (SEM) fall between 1 and 40 μm. Meanwhile, thermal analyses show no physical or chemical change for the prepared pyrochlores. The relative densities of the densified pellets for AC impedance measurements are above 85% and the measured relative permittivity, ɛ′ and dielectric loss, tan δ for composition, x = 0.2 at ambient temperature are ∼60 and 0.07 at 1 MHz, respectively. The calculated activation energies are 0.32–0.40 eV and the conductivity values, Y′ are in the order of 10−3 at 400 °C. The conduction mechanisms of BCT pyrochlores are probably attributed to the oxygen non-stoichiometry and mixed valency of copper within the structure
Novel monoclinic zirconolite in Bi2O3-CuO-Ta2O5 ternary system: phase equilibria, structural and electrical properties
Synthesis of novel monoclinic zirconolite, Bi1.92Cu0.08(Cu0.3Ta0.7)2O7.06 (β-BCT) using solid state reaction had been finalised at the firing temperature of 900 °C over 24 h. The X–ray diffraction pattern of β-BCT was fully indexed on a monoclinic symmetry, space group, C2/c with lattice constants, a = 13.1052 (8), b = 7.6749 (5), c = 12.162 (6), α = γ = 90° and β = 101.32° (1), respectively. The reaction mechanism study indicated phase formation was greatly influenced by the reaction between intermediate bismuth tantalate binary phases and CuO at elevated temperatures. β-BCT was thermally stable up to a temperature of 900 °C and contained spherulite grains with sizes ranging from 1 to 14 μm. Electrical properties of this material were characterised over a broad temperature range covering temperatures from 10 K to 874 K. At the temperature of 304 K, two semicircles were discernible in complex Cole–Cole plot showing an insulating grain boundary with Cgb = 6.63 × 10−9 F cm−1 and a bulk response capacitance, Cb = 6.74 × 10−12 F cm−1. The Power law frequency-dependent ac conductivity of β-BCT was apparent in three frequency regimes; a low–frequency plateau regime, a high-frequency plateau regime and a dispersive regime taking place in the temperature range of 220–576 K. The frequency-dependent ac conductivity of β-BCT with increasing temperature was attributed to the thermal activated electrical conduction mechanism within the structure
Yinchen Linggui Zhugan Decoction Ameliorates Nonalcoholic Fatty Liver Disease in Rats by Regulating the Nrf2/ARE Signaling Pathway
Yinchen Linggui Zhugan Decoction (YCLGZGD) is the combination of Linggui Zhugan (LGZGD) and Yinchenhao (YCHD) decoctions, two famous traditional Chinese medicine prescriptions. In previous studies, we found that Yinchen Linggui Zhugan Decoction (YCLGZGD) could regulate lipid metabolism disorder and attenuate inflammation in pathological process of nonalcoholic fatty liver disease (NAFLD). However, the exact underlying mechanism remains unknown. The aim of this study was to explore the effect of Yinchen Linggui Zhugan Decoction on experimental NAFLD and its mechanism in rats with high-fat diet (HFD) which was established by 8-week administration of HFD. YCLGZGD, LGZGD, and YCHD were administered daily for 4 weeks, after which the rats were euthanized. The level of blood lipid, liver enzymes, H&E, and Oil Red O staining were determined to evaluate NAFLD severity. Western blotting and real-time polymerase chain reaction were, respectively, used to determine hepatic protein and gene expression of Keap1, Nrf2, NQO1, and HO-1. Oral YCLGZGD ameliorated HFD-induced NAFLD. Furthermore, YCLGZGD increased the protein and gene expression of Nrf2, NQO1, and HO-1 without changing Keap1. Overall, these results suggest that YCLGZGD ameliorates HFD-induced NAFLD in rats by upregulating the Nrf2/ARE signaling pathway
Phase equilibria in the Bi2O3-CuO-Nb2O5 ternary system
A complete subsolidus ternary phase diagram of the Bi2O3-CuO-Nb2O5 (BCN) system was constructed. Careful firing control and phase analysis were applied to determine the phase assemblages and compatibilities over a wide range of temperatures, i.e. 700–925 °C. Phase-pure BCN pyrochlores were found to crystallise in cubic symmetry, space group Fd3m, No. 227 with lattice constants in the range of 10.4855 (5)<x<10.5321 (3). The mechanism of this limited subsolidus series could be represented by a general formula, Bi3.08−xCu1.84+2x/9Nb3.08+7x/9O14.16+6x/9 (0≤x≤0.36) wherein the reduction in Bi content was compensated by a proportion amount of copper and niobium together with non-stoichiometry in oxygen
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