| 1. |
- Kim, Joon Tae, et al.
(author)
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Dual antiplatelet Use for extended period taRgeted to AcuTe ischemic stroke with presumed atherosclerotic OrigiN (DURATION) trial : Rationale and design
- 2023
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In: International Journal of Stroke. - : SAGE Publications. - 1747-4930 .- 1747-4949. ; 18:8, s. 1015-1020
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Journal article (peer-reviewed)abstract
- Rationale: The optimal duration of dual antiplatelet therapy (DAPT) with clopidogrel-aspirin for the large artery atherosclerotic (LAA) stroke subtype has been debated. Aims: To determine whether the 1-year risk of recurrent vascular events could be reduced by a longer duration of DAPT in patients with the LAA stroke subtype. Methods and study design: A total of 4806 participants will be recruited to detect a statistically significant relative risk reduction of 22% with 80% power and a two-sided alpha error of 0.05, including a 10% loss to follow-up. This is a registry-based, multicenter, prospective, randomized, open-label, blinded end point study designed to evaluate the efficacy and safety of a 12-month duration of DAPT compared with a 3-month duration of DAPT in the LAA stroke subtype. Patients will be randomized (1:1) to either DAPT for 12 months or DAPT for 3 months, followed by monotherapy (either aspirin or clopidogrel) for the remaining 9 months. Study outcomes: The primary efficacy outcome of the study is a composite of stroke (ischemic or hemorrhagic), myocardial infarction, and all-cause mortality for 1 year after the index stroke. The secondary efficacy outcomes are (1) stroke, (2) ischemic stroke or transient ischemic attack, (3) hemorrhagic stroke, and (4) all-cause mortality. The primary safety outcome is major bleeding. Discussion: This study will help stroke physicians determine the appropriate duration of dual therapy with clopidogrel-aspirin for patients with the LAA stroke subtype. Trial registration: URL: https://cris.nih.go.kr/cris. CRIS Registration Number: KCT0004407.
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| 2. |
- Li, He, et al.
(author)
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Enhanced production of trehalose in Escherichia coli by homologous expression of otsBA in the presence of the trehalase inhibitor, validamycin A, at high osmolarity
- 2012
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In: Journal of Bioscience and Bioengineering. - : Elsevier. - 1389-1723 .- 1347-4421. ; 113:2, s. 224-232
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Journal article (peer-reviewed)abstract
- Trehalose production in Escherichia coli DH5α was explored by overexpressing otsBA operon encoding trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase. Production and subsequent degradation of trehalose resulted in low production of trehalose in engineered cells overexpressing otsBA, which was primarily due to the concomitant expression of endogenous trehalase. Through an in vitro enzyme assay and flask cultures of engineered cells, trehalase expression was shown to be directly related to the expression of otsBA rather than osmotic stress. Validamycin A effectively inhibited E. coli trehalase and the intracellular accumulation of trehalose was markedly enhanced in the presence of validamycin A at an optimal concentration in the medium. The trehalose production was further increased upon growth in a hypertonic medium in the presence of validamycin A, with most trehalose accumulating as an intracellular product. The highest titer was obtained when otsBA expression was induced by a medium-copy vector, ptrc99A, with 0.5mM of isopropyl β-d-1-thiogalactopyranoside. Trehalose titer was 1.7 g/L in controlled bioreactor cultures using synthetic M9 medium supplemented with 40 g/L glycerol, 0.1mM validamycin A, and 300 mM NaCl.
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| 3. |
- Li, He, et al.
(author)
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Quantitative analysis of valiolamine through pre-column derivatization with phenylisocyanate using high-performance liquid chromatography with UV detection : Selection of reagent, identification of derivative and optimization of derivatization conditions
- 2009
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In: Journal of Pharmaceutical and Biomedical Analysis. - : Elsevier. - 0731-7085 .- 1873-264X. ; 49:4, s. 957-963
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Journal article (peer-reviewed)abstract
- This report describes the improved quantitative determination of valiolamine in a medium for microbial culture using high-performance liquid chromatography with UV detection. Valiolamine aqueous solution was dried, dissolved in dimethyl sulfoxide and derivatization performances of phenylisocyanate (PHI), 1-fluoro-2,4-dinitrobenznene and 1-naphthylisothiocyanate were compared in the presence of triethylamine. The PHI was chosen as the most suitable derivatization reagent and the valiolamine-PHI derivative was identified by thin-layer chromatography and electrospray ionization mass spectrometry. The derivative eluted at 10.5 min on a reverse-phase column using a mobile phase composed of 10% acetonitrile in water containing 0.5 mM sodium octyl sulfate (pH 3.0), at a column flow rate of 1.0 mL/min with UV detection at 240 nm. The optimum conditions for derivatization were a reaction temperature of 30 degrees C, reaction time of 30 min, and PHI concentration higher than 33.6 mM. Calibration curves were linear in the range of 0.99-19.95 microg/mL for the standard solutions and 24.9-99.7 microg/mL for the spiked sample. The proposed method was validated and proven to be selective, accurate and precise and suitable for the quantitative analysis of valiolamine in medium for microbial cultures.
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| 4. |
- Suh, Sang Heon, et al.
(author)
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Gut microbiota regulates lacteal integrity by inducing VEGF-C in intestinal villus macrophages
- 2019
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In: EMBO Reports. - : WILEY. - 1469-221X .- 1469-3178. ; 20:4
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Journal article (peer-reviewed)abstract
- A lacteal is a blunt-ended, long, tube-like lymphatic vessel located in the center of each intestinal villus that provides a unique route for drainage of absorbed lipids from the small intestine. However, key regulators for maintaining lacteal integrity are poorly understood. Here, we explore whether and how the gut microbiota regulates lacteal integrity. Germ depletion by antibiotic treatment triggers lacteal regression during adulthood and delays lacteal maturation during the postnatal period. In accordance with compromised lipid absorption, the button-like junction between lymphatic endothelial cells, which is ultrastructurally open to permit free entry of dietary lipids into lacteals, is significantly reduced in lacteals of germ-depleted mice. Lacteal defects are also found in germ-free mice, but conventionalization of germ-free mice leads to normalization of lacteals. Mechanistically, VEGF-C secreted from villus macrophages upon MyD88-dependent recognition of microbes and their products is a main factor in lacteal integrity. Collectively, we conclude that the gut microbiota is a crucial regulator for lacteal integrity by endowing its unique microenvironment and regulating villus macrophages in small intestine.
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