100 research outputs found
The Hide-and-Seek of Grain Boundaries from Moire Pattern Fringe of Two-Dimensional Graphene
Grain boundaries (GBs) commonly exist in crystalline materials and affect various properties of materials. The facile identification of GBs is one of the significant requirements for systematical study of polycrystalline materials including recently emerging two-dimensional materials. Previous observations of GBs have been performed by various tools including high resolution transmission electron microscopy. However, a method to easily identify GBs, especially in the case of low-angle GBs, has not yet been well established. In this paper, we choose graphene bilayers with a GB as a model system and investigate the effects of interlayer rotations to the identification of GBs. We provide a critical condition between adjacent moire fringe spacings, which determines the possibility of GB recognition. In addition, for monolayer graphene with a grain boundary, we demonstrate that low-angle GBs can be distinguished easily by inducing moire patterns deliberately with an artificial reference overlayopen0
Cyclic Nucleotide-Gated Channels Contribute to Thromboxane A2-Induced Contraction of Rat Small Mesenteric Arteries
Background: Thromboxane A 2 (TxA 2)-induced smooth muscle contraction has been implicated in cardiovascular, renal and respiratory diseases. This contraction can be partly attributed to TxA2-induced Ca 2+ influx, which resulted in vascular contraction via Ca 2+-calmodulin-MLCK pathway. This study aims to identify the channels that mediate TxA2-induced Ca 2+ influx in vascular smooth muscle cells. Methodology/Principal Findings: Application of U-46619, a thromboxane A2 mimic, resulted in a constriction in endothelium-denuded small mesenteric artery segments. The constriction relies on the presence of extracellular Ca 2+, because removal of extracellular Ca 2+ abolished the constriction. This constriction was partially inhibited by an L-type Ca 2+ channel inhibitor nifedipine (0.5–1 mM). The remaining component was inhibited by L-cis-diltiazem, a selective inhibitor for CNG channels, in a dose-dependent manner. Another CNG channel blocker LY83583 [6-(phenylamino)-5,8-quinolinedione] had similar effect. In the primary cultured smooth muscle cells derived from rat aorta, application of U46619 (100 nM) induced a rise in cytosolic Ca 2+ ([Ca 2+]i), which was inhibited by L-cis-diltiazem. Immunoblot experiments confirmed the presence of CNGA2 protein in vascular smooth muscle cells. Conclusions/Significance: These data suggest a functional role of CNG channels in U-46619-induced Ca 2+ influx and contraction of smooth muscle cells
Number of People Blind or Visually Impaired by Glaucoma Worldwide and in World Regions 1990 – 2010: A Meta-Analysis
Objective:
To assess the number of individuals visually impaired or blind due to glaucoma and to examine regional differences and temporal changes in this parameter for the period from 1990 to 2012.
Methods:
As part of the Global Burden of Diseases (GBD) Study 2010, we performed a systematic literature review for the period from 1980 to 2012. We primarily identified 14,908 relevant manuscripts, out of which 243 high-quality, population-based studies remained after review by an expert panel that involved application of selection criteria that dwelt on population representativeness and clarity of visual acuity methods used. Sixty-six specified the proportion attributable to glaucoma. The software tool DisMod-MR (Disease Modeling–Metaregression) of the GBD was used to calculate fraction of vision impairment due to glaucoma.
Results:
In 2010, 2.1 million (95% Uncertainty Interval (UI):1.9,2.6) people were blind, and 4.2 (95% UI:3.7,5.8) million were visually impaired due to glaucoma. Glaucoma caused worldwide 6.6% (95% UI:5.9,7.9) of all blindness in 2010 and 2.2% (95% UI:2.0,2.8) of all moderate and severe visual impairment (MSVI). These figures were lower in regions with younger populations (10%). From 1990 to 2010, the number of blind or visually impaired due to glaucoma increased by 0.8 million (95%UI:0.7, 1.1) or 62% and by 2.3 million (95%UI:2.1,3.5) or 83%, respectively. Percentage of global blindness caused by glaucoma increased between 1990 and 2010 from 4.4% (4.0,5.1) to 6.6%. Age-standardized prevalence of glaucoma related blindness and MSVI did not differ markedly between world regions nor between women.
Significance:
By 2010, one out of 15 blind people was blind due to glaucoma, and one of 45 visually impaired people was visually impaired, highlighting the increasing global burden of glaucoma
IlsA, A Unique Surface Protein of Bacillus cereus Required for Iron Acquisition from Heme, Hemoglobin and Ferritin
The human opportunistic pathogen Bacillus cereus belongs to the B. cereus group that includes bacteria with a broad host spectrum. The ability of these bacteria to colonize diverse hosts is reliant on the presence of adaptation factors. Previously, an IVET strategy led to the identification of a novel B. cereus protein (IlsA, Iron-regulated leucine rich surface protein), which is specifically expressed in the insect host or under iron restrictive conditions in vitro. Here, we show that IlsA is localized on the surface of B. cereus and hence has the potential to interact with host proteins. We report that B. cereus uses hemoglobin, heme and ferritin, but not transferrin and lactoferrin. In addition, affinity tests revealed that IlsA interacts with both hemoglobin and ferritin. Furthermore, IlsA directly binds heme probably through the NEAT domain. Inactivation of ilsA drastically decreases the ability of B. cereus to grow in the presence of hemoglobin, heme and ferritin, indicating that IlsA is essential for iron acquisition from these iron sources. In addition, the ilsA mutant displays a reduction in growth and virulence in an insect model. Hence, our results indicate that IlsA is a key factor within a new iron acquisition system, playing an important role in the general virulence strategy adapted by B. cereus to colonize susceptible hosts
Current Antiviral Therapy of Chronic Hepatitis B: Efficacy and Safety
The treatment of chronic hepatitis B is in constant evolution. Interferon, the first agent licensed for chronic hepatitis B treatment, has been superseded by the growing popularity of nucleoside/nucleotide analogues (NA). However, resistance to these agents is a major challenge. Newer NAs, such as entecavir and tenofovir dipivoxil fumarate, have very low resistance rates and favorable safety profiles. Long-term use of these agents can effectively suppress hepatitis B virus DNA, leading to decrease in incidence of hepatitic flares, as well as in the development of cirrhosis and hepatocellular carcinoma. The efficacy and safety of various antiviral agents is discussed in this review
Global gene expression profile progression in Gaucher disease mouse models
<p>Abstract</p> <p>Background</p> <p>Gaucher disease is caused by defective glucocerebrosidase activity and the consequent accumulation of glucosylceramide. The pathogenic pathways resulting from lipid laden macrophages (Gaucher cells) in visceral organs and their abnormal functions are obscure.</p> <p>Results</p> <p>To elucidate this pathogenic pathway, developmental global gene expression analyses were conducted in distinct <it>Gba1 </it>point-mutated mice (V394L/V394L and D409 V/null). About 0.9 to 3% of genes had altered expression patterns (≥ ± 1.8 fold change), representing several categories, but particularly macrophage activation and immune response genes. Time course analyses (12 to 28 wk) of INFγ-regulated pro-inflammatory (13) and IL-4-regulated anti-inflammatory (11) cytokine/mediator networks showed tissue differential profiles in the lung and liver of the <it>Gba1 </it>mutant mice, implying that the lipid-storage macrophages were not functionally inert. The time course alterations of the INFγ and IL-4 pathways were similar, but varied in degree in these tissues and with the <it>Gba1 </it>mutation.</p> <p>Conclusions</p> <p>Biochemical and pathological analyses demonstrated direct relationships between the degree of tissue glucosylceramides and the gene expression profile alterations. These analyses implicate IFNγ-regulated pro-inflammatory and IL-4-regulated anti-inflammatory networks in differential disease progression with implications for understanding the Gaucher disease course and pathophysiology.</p
Stroke genetics informs drug discovery and risk prediction across ancestries
Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries
Accurate sequential detection of primary tumor and metastatic lymphatics using a temperature-induced phase transition nanoparticulate system
Keun Sang Oh,1 Ji Young Yhee,2 Dong-Eun Lee,3 Kwangmeyung Kim,2 Ick Chan Kwon,2 Jae Hong Seo,4 Sang Yoon Kim,5 Soon Hong Yuk1,4 1College of Pharmacy, Korea University, Sejong, 2Biomedical Research Center, Korea Institute of Science and Technology, Seoul, 3Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeonbuk, 4Biomedical Research Center, Korea University Guro Hospital, Seoul, 5Department of Otolaryngology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Republic of Korea Abstract: Primary tumor and tumor-associated metastatic lymphatics have emerged as new targets for anticancer therapy, given that these are difficult to treat using traditional chemotherapy. In this study, docetaxel-loaded Pluronic nanoparticles with Flamma™ (FPR-675, fluorescence molecular imaging dye; DTX/FPR-675 Pluronic NPs) were prepared using a temperature-induced phase transition for accurate detection of metastatic lymphatics. Significant accumulation was seen at the primary tumor and in metastatic lymph nodes within a short time. Particle size, maximum drug loading capacity, and drug encapsulation efficiency of the docetaxel-loaded Pluronic NPs were approximately 10.34±4.28 nm, 3.84 wt%, and 94±2.67 wt%, respectively. Lymphatic tracking after local and systemic delivery showed that DTX/FPR-675 Pluronic NPs were more potent in tumor-bearing mice than in normal mice, and excised mouse lymphatics showed stronger near-infrared fluorescence intensity on the tumor-bearing side than on the non-tumor-bearing side at 60 minutes post-injection. In vivo cytotoxicity and efficacy data for the NPs demonstrated that the systemically administered NPs caused little tissue damage and had minimal side effects in terms of slow renal excretion and prolonged circulation in tumor-bearing mice, and rapid renal excretion in non-tumor-bearing mice using an in vivo real-time near-infrared fluorescence imaging system. These results clearly indicate that docetaxel-loaded Pluronic NPs could provide a strategy to achieve effective cancer therapy by simultaneous delivery to primary tumors, tumor lymphatics, and tumor-associated metastatic lymphatics. Keywords: metastatic lymphatics, primary tumor targeting, lymphatic tracking, temperature-induced phase transition, Pluronic nanoparticle
Docetaxel-loaded multilayer nanoparticles with nanodroplets for cancer therapy
Keun Sang Oh,1,* Kyungim Kim,1,* Byeong Deok Yoon,1 Hye Jin Lee,1 Dal Yong Park,1 Eun-yeong Kim,1 Kiho Lee,1 Jae Hong Seo,2 Soon Hong Yuk1,2 1College of Pharmacy, Korea University, Sejong, 2Biomedical Research Center, Korea University Guro Hospital, Guro-gu, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: A mixture of docetaxel (DTX) and Solutol® HS 15 (Solutol) transiently formed nanodroplets when it was suspended in an aqueous medium. However, nanodroplets that comprised DTX and Solutol showed a rapid precipitation of DTX because of their unstable characteristics in the aqueous medium. The incorporation of nanodroplets that comprised DTX and Solutol through vesicle fusion and subsequent stabilization was designed to prepare multilayer nanoparticles (NPs) with a DTX-loaded Solutol nanodroplet (as template NPs) core for an efficient delivery of DTX as a chemotherapeutic drug. As a result, the DTX-loaded Solutol nanodroplets (~11.7 nm) were observed to have an increased average diameter (from 11.7 nm to 156.1 nm) and a good stability of the hydrated NPs without precipitation of DTX by vesicle fusion and multilayered structure, respectively. Also, a long circulation of the multilayer NPs was observed, and this was due to the presence of Pluronic F-68 on the surface of the multilayer NPs. This led to an improved antitumor efficacy based on the enhanced permeation and retention effect. Therefore, this study indicated that the multilayer NPs have a considerable potential as a drug delivery system with an enhanced therapeutic efficacy by blood circulation and with low side effects. Keywords: multilayer nanoparticles, Solutol, Pluronic F-68, docetaxel, cancer therap
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