119 research outputs found
Protection of NAD(P)H: Quinone oxidoreductase 1 against renal ischemia/reperfusion injury in mice
No full textIschemia/reperfusion (I/R) is the most common cause of acute renal injury. I/R-induced reactive oxygen species (ROS) are thought to be a major factor in the development of acute renal injury by promoting the initial tubular damage. NAD(P)H:quinone oxidoreductase 1 (NQO1) is a well-known antioxidant protein that regulates ROS generation. The purpose of this study was to investigate whether NQO1 modulates the renal I/R injury (IRI) associated with NADPH oxidase (NOX)-derived ROS production in an animal model. We analyzed renal function, oxidative stress, and tubular apoptosis after IRI. NQO1-/- mice showed increased blood urea nitrogen and creatinine levels, tubular damage, oxidative stress, and apoptosis. In the kidneys of NQO1-/- mice, the cellular NADPH/NADP+ ratio was significantly higher and NOX activity was markedly higher than in those of NQO1+/+ mice. The activation of NQO1 by β-lapachone (βL) significantly improved renal dysfunction and reduced tubular cell damage, oxidative stress, and apoptosis by renal I/R. Moreover, the βL treatment significantly lowered the cellular NADPH/NADP+ ratio and dramatically reduced NOX activity in the kidneys after IRI. From these results, it was concluded that NQO1 has a protective role against renal injury induced by I/R and that this effect appears to be mediated by decreased NOX activity via cellular NADPH/NADP+ modulation. These results provide convincing evidence that NQO1 activation might be beneficial for ameliorating renal injury induced by I/R.open
Fuzzy implicative hyper BCK-ideals of hyper BCK-algebras
Get PDFWe consider the fuzzification of the notion of implicative hyper
BCK-ideals, and then investigate several properties.
Using the concept of level subsets, we give a
characterization of a fuzzy implicative hyper BCK-ideal. We state
a relation between a fuzzy hyper BCK-ideal and a fuzzy implicative
hyper BCK-ideal. We establish a condition for a fuzzy hyper
BCK-ideal to be a fuzzy implicative hyper BCK-ideal. Finally, we
introduce the notion of hyper homomorphisms of hyper
BCK-algebras, and discuss related properties
Fuzzy associative ℐ-ideals of IS-algebras
No full textWe fuzzify the concept of an associative ℐ-ideal in
an IS-algebra. We give a relation between a fuzzy
ℐ-ideal and a fuzzy associative ℐ-ideal,
and we investigate some related properties
Chemotherapeutic Agent Paclitaxel Mediates Priming of NLRP3 Inflammasome Activation
Get PDFPaclitaxelis achemotherapeuticdrug commonly used to treat different types of cancer. In addition to its antitumor effect,paclitaxelis also known to promote Toll-like receptor (TLR) 4-dependent inflammatory responses, which may lower itschemotherapeuticefficacy. However, it remains unclear whetherpaclitaxelis able to affectinflammasomesignaling in myeloid or cancer cells. Therefore, we examined the potential effect ofpaclitaxelon theactivationof aninflammasomecomplex by examining caspase-1activationand interleukin (IL)-1β secretion in bone marrow-derived macrophages (BMDMs). The results showed that treatment withpaclitaxelalone or following LPSprimingfailed to trigger the secretion ofactivecaspase-1 and IL-1β from BMDMs. However,paclitaxelcould induce robustactivationof caspase-1 in BMDMs in the presence ofNLRP3inflammasome-activatingsignal 2, such as ATP or nigericin. Thispaclitaxel/ATP-mediatedinflammasomeactivationwas completely abrogated inNlrp3-deficient macrophages. Mechanistically,paclitaxeltreatment induced robustactivationof the TLR4 signaling cascade, including phosphorylation of IκB and JNK and upregulation of proinflammatory cytokine mRNA levels in a TLR4-dependent manner. In contrast,paclitaxeltreatment alone did not induce mitochondrial damages such as the loss of the mitochondrial membrane potential and production of mitochondrial ROS. These findings suggest thatpaclitaxelcan drive theprimingof signal-mediatedevents forNLRP3activationbut not a second signal-triggered phenomenon such as mitochondrial damage. This suggestion was supported by the observations thatpaclitaxeltreatment caused robust IL-1β production in macrophages in the presence of cell-free medium derived from growth of injured cells and also in the spleen of mice. Collectively, our data strongly indicate thatpaclitaxelis able to facilitate theactivationofNLRP3inflammasomesignaling in a certain physiological environment.ope
Advanced Boiling-A Scalable Strategy for Self-Assembled Three-Dimensional Graphene
No full textCurrently, researchers are paying much attention to the development of effective 3D graphene for applications in energy storage and environmental purification. Before commercialization, however, it is necessary to develop a method that allows for the large-scale production of such materials and enables good control over their structural and chemical properties. With this objective, we herein developed a simple method for the formation of large-scale (4 in. wafer) 3D graphene networks via the self-assembly of graphene sheets at a superheated liquid-vapor interface. The structural morphology of this porous network could be modified by controlling the vaporization rate, surface temperature of the target substrate, and amount of discharged colloids. The key mechanism behind this intriguing result was investigated by high-speed visualization of microdroplet behavior and extensive thermal analysis. This self-assembled 3D graphene had excellent electrical and mechanical properties. Our approach can be directly used for the mass production of graphene-based materials.11Nsciescopu
Altered cortical functional network in major depressive disorder: A resting-state electroencephalogram study
No full textBackground: Electroencephalogram (EEG)-based brain network analysis is a useful biological correlate reflecting brain function. Sensor-level network analysis might be contaminated by volume conduction and does not explain regional brain characteristics. Source-level network analysis could be a useful alternative. We analyzed EEG-based source-level network in major depressive disorder (MDD). Method: Resting-state EEG was recorded in 87 MDD and 58 healthy controls, and cortical source signals were estimated. Network measures were calculated: global indices (strength, clustering coefficient (CC), path length (PL), and efficiency) and nodal indices (eigenvector centrality and nodal CC) in six frequency. Correlation analyses were performed between network indices and symptom scales. Results: At the global level, MDD showed decreased strength, CC in theta and alpha bands, and efficiency in alpha band, while enhanced PL in alpha band. At nodal level, eigenvector centrality of alpha band showed region dependent changes in MDD. Nodal CCs of alpha band were reduced in MDD and were negatively correlated with depression and anxiety scales. Conclusion: Disturbances in EEG-based brain network indices might reflect altered emotional processing in MDD. These source-level network indices might provide useful biomarkers to understand regional brain pathology in MDD. Keywords: Major depressive disorder, Electroencephalogram, Brain electrical activity mapping, Source-level brain networ
Sildenafil and beraprost combination therapy in patients with pulmonary hypertension undergoing valvular heart surgery
No full textBACKGROUND AND AIM OF THE STUDY: Sildenafil and beraprost, as orally available pulmonary vasodilators, are used increasingly to treat pulmonary hypertension (PH). An evaluation was made, in patients with PH undergoing valvular heart surgery, as to whether preoperative combined oral sildenafil and beraprost treatment could induce synergistic and prolonged pulmonary vasodilation, or result in a loss of pulmonary selectivity.
METHODS: Fifty patients scheduled for valvular heart surgery with a mean pulmonary arterial pressure (PAP) > 30 mmHg were randomly assigned to receive either 50 mg oral sildenafil + 40 microg beraprost, or a placebo, 15 min before the induction of anesthesia. Hemodynamic variables were measured intraoperatively.
RESULTS: The treatment group had a significantly lower systemic vascular resistance index at 60 min after medication. No other significant intergroup differences in hemodynamic variables were observed. In addition, significantly more patients in the treatment group required vasopressor therapy. In both groups, the PAP was significantly reduced by general anesthesia, and almost normalized after valvular heart surgery.
CONCLUSION: Preoperative oral sildenafil and beraprost treatment resulted in a loss of pulmonary selectivity, and did not provide any additional pulmonary vasodilation or favorable perioperative hemodynamics in patients with PH undergoing valvular heart surgery.ope
Bright visible light emission from graphene
No full textGraphene and related two-dimensional materials are promising candidates for atomically thin, flexible and transparent opto-electronics(1,2). In particular, the strong light-matter interaction in graphene(3) has allowed for the development of state-of-the-art photodetectors(4,5), optical modulators(6) and plasmonic devices(7). In addition, electrically biased graphene on SiO2 substrates can be used as a low-efficiency emitter in the mid-infrared range(8,9). However, emission in the visible range has remained elusive. Here, we report the observation of bright visible light emission from electrically biased suspended graphene devices. In these devices, heat transport is greatly reduced(10). Hot electrons (similar to 2,800 K) therefore become spatially localized at the centre of the graphene layer, resulting in a 1,000-fold enhancement in thermal radiation efficiency(8,9). Moreover, strong optical interference between the suspended graphene and substrate can be used to tune the emission spectrum. We also demonstrate the scalability of this technique by realizing arrays of chemical-vapour-deposited graphene light emitters. These results pave the way towards the realization of commercially viable large-scale, atomically thin, flexible and transparent light emitters and displays with low operation voltage and graphene-based on-chip ultrafast optical communications.Y
Cortical volume and 40-Hz auditory-steady-state responses in patients with schizophrenia and healthy controls
No full textBackground: Abnormalities in the 40-Hz auditory steady-state response (ASSR) of the gamma range have been reported in schizophrenia (SZ) and are regarded as important pathophysiological features. Many of the previous studies reported diminished gamma oscillations in SZ, although some studies reported increased spontaneous gamma oscillations. Furthermore, brain morphological correlates of the gamma band ASSR deficits have rarely examined. We investigated different measures of the 40-Hz ASSR and their association with brain volumes and psychological measures of SZ. Methods: The 40-Hz ASSR was measured for 80 dB click sounds (1 ms, 500-ms trains at 40-Hz, with 3050 to 3500 inter-train interval) using electroencephalography with 64 electrodes in 33 patients with SZ (male: 16, female: 17 (age range: 21–60)) and 30 healthy controls (HCs) (male: 13, female: 17 (age range: 23–64)). Four gamma oscillation measures (evoked power, spontaneous oscillations (baseline and total power), and inter-trial phase coherence (ITC)) were assessed. The source activities of the ASSR were also analyzed. Brain volumes were assessed using high-resolution magnetic resonance imaging and voxel-based morphometry and superior temporal gyrus (STG) volume measures were obtained. Results: Patients with SZ had larger total and evoked powers and higher ITC than HCs. Both groups showed significantly different association between mean evoked power and right STG volume. In HCs but not SZ, mean evoked power showed significant positive correlation with right STG volume. In addition, the two groups showed significantly different association between verbal fluency and mean evoked power. High evoked power was significantly correlated with poor verbal fluency in SZ. Conclusions: The current study found increased gamma oscillation in SZ and suggests significant involvement of the STG in gamma oscillations. Keywords: 40-Hz ASSR, Gamma oscillation, STG volume, Schizophrenia, Voxel-based morphometr
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