Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
136
result(s) for
"Lee, Sung-Uk"
Sort by:
Increasing cell permeability of N-acetylglucosamine via 6-acetylation enhances capacity to suppress T-helper 1 (TH1)/TH17 responses and autoimmunity
by
Demetriou, Michael
,
Li, Carey F.
,
Dennis, James W.
in
Acetic acid
,
Acetylation
,
Acetylglucosamine - immunology
2019
N-acetylglucosamine (GlcNAc) branching of Asn (N)-linked glycans inhibits pro-inflammatory T cell responses and models of autoimmune diseases such as Multiple Sclerosis (MS). Metabolism controls N-glycan branching in T cells by regulating de novo hexosamine pathway biosynthesis of UDP-GlcNAc, the donor substrate for the Golgi branching enzymes. Activated T cells switch metabolism from oxidative phosphorylation to aerobic glycolysis and glutaminolysis. This reduces flux of glucose and glutamine into the hexosamine pathway, thereby inhibiting de novo UDP-GlcNAc synthesis and N-glycan branching. Salvage of GlcNAc into the hexosamine pathway overcomes this metabolic suppression to restore UDP-GlcNAc synthesis and N-glycan branching, thereby promoting anti-inflammatory T regulatory (Treg) over pro-inflammatory T helper (TH) 17 and TH1 differentiation to suppress autoimmunity. However, GlcNAc activity is limited by the lack of a cell surface transporter and requires high doses to enter cells via macropinocytosis. Here we report that GlcNAc-6-acetate is a superior pro-drug form of GlcNAc. Acetylation of amino-sugars improves cell membrane permeability, with subsequent de-acetylation by cytoplasmic esterases allowing salvage into the hexosamine pathway. Per- and bi-acetylation of GlcNAc led to toxicity in T cells, whereas mono-acetylation at only the 6 > 3 position raised N-glycan branching greater than GlcNAc without inducing significant toxicity. GlcNAc-6-acetate inhibited T cell activation/proliferation, TH1/TH17 responses and disease progression in Experimental Autoimmune Encephalomyelitis (EAE), a mouse model of MS. Thus, GlcNAc-6-Acetate may provide an improved therapeutic approach to raise N-glycan branching, inhibit pro-inflammatory T cell responses and treat autoimmune diseases such as MS.
Journal Article
Notch signal strength controls cell fate in the haemogenic endothelium
2015
Acquisition of the arterial and haemogenic endothelium fates concurrently occur in the aorta–gonad–mesonephros (AGM) region prior to haematopoietic stem cell (HSC) generation. The arterial programme depends on Dll4 and the haemogenic endothelium/HSC on Jag1-mediated Notch1 signalling. How Notch1 distinguishes and executes these different programmes in response to particular ligands is poorly understood. By using two Notch1 activation trap mouse models with different sensitivity, here we show that arterial endothelial cells and HSCs originate from distinct precursors, characterized by different Notch1 signal strengths. Microarray analysis on AGM subpopulations demonstrates that the Jag1 ligand stimulates low Notch strength, inhibits the endothelial programme and is permissive for HSC specification. In the absence of Jag1, endothelial cells experience high Dll4-induced Notch activity and select the endothelial programme, thus precluding HSC formation. Interference with the Dll4 signal by ligand-specific blocking antibodies is sufficient to inhibit the endothelial programme and favour specification of the haematopoietic lineage.
It is unclear how Notch1 signals regulate both the maintenance of the endothelial fate and the endothelial-to-hematopoietic transition in the embryonic aorta. Here the authors show that those cells in which Notch1 ligand Jag1 is out-competed by Dll4 remain endothelial, while higher Jag1 activity leads to generation of hematopoietic stem cells.
Journal Article
Wireless, multimodal sensors for continuous measurement of pressure, temperature, and hydration of patients in wheelchair
by
Lee, Soyeong
,
Gu, Jimin
,
Sung, Hyung Jin
in
639/166/987
,
639/301/357/995
,
Chemistry and Materials Science
2023
Individuals who are unable to walk independently spend most of the day in a wheelchair. This population is at high risk for developing pressure injuries caused by sitting. However, early diagnosis and prevention of these injuries still remain challenging. Herein, we introduce battery-free, wireless, multimodal sensors and a movable system for continuous measurement of pressure, temperature, and hydration at skin interfaces. The device design includes a crack-activated pressure sensor with nanoscale encapsulations for enhanced sensitivity, a temperature sensor for measuring skin temperature, and a galvanic skin response sensor for measuring skin hydration levels. The movable system enables power harvesting, and data communication to multiple wireless devices mounted at skin-cushion interfaces of wheelchair users over full body coverage. Experimental evaluations and numerical simulations of the devices, together with clinical trials for wheelchair patients, demonstrate the feasibility and stability of the sensor system for preventing pressure injuries caused by sitting.
Journal Article
Genetics and the environment converge to dysregulate N-glycosylation in multiple sclerosis
2011
How environmental factors combine with genetic risk at the molecular level to promote complex trait diseases such as multiple sclerosis (MS) is largely unknown. In mice,
N
-glycan branching by the Golgi enzymes Mgat1 and/or Mgat5 prevents T cell hyperactivity, cytotoxic T-lymphocyte antigen 4 (CTLA-4) endocytosis, spontaneous inflammatory demyelination and neurodegeneration, the latter pathologies characteristic of MS. Here we show that MS risk modulators converge to alter
N
-glycosylation and/or CTLA-4 surface retention conditional on metabolism and vitamin D
3
, including genetic variants in interleukin-7 receptor-α (
IL7RA
*C), interleukin-2 receptor-α (
IL2RA
*T),
MGAT1
(IV
A
V
T−T
) and
CTLA-4
(Thr17Ala). Downregulation of Mgat1 by
IL7RA
*C and
IL2RA
*T is opposed by
MGAT1
(IV
A
V
T−T
) and vitamin D
3
, optimizing branching and mitigating MS risk when combined with enhanced CTLA-4
N
-glycosylation by
CTLA-4
Thr17. Our data suggest a molecular mechanism in MS whereby multiple environmental and genetic inputs lead to dysregulation of a final common pathway, namely
N
-glycosylation.
Complex diseases such as multiple sclerosis have both genetic and environmental components. This study demonstrates that variants of genes implicated in multiple sclerosis, and alterations in cellular metabolism and vitamin D3 levels, alter
N
-glycosylation, a post-translational modification causal of the disease in mice.
Journal Article
Temperature-Controlled Direct Imprinting of Ag Ionic Ink: Flexible Metal Grid Transparent Conductors with Enhanced Electromechanical Durability
2017
Next-generation transparent conductors (TCs) require excellent electromechanical durability under mechanical deformations as well as high electrical conductivity and transparency. Here we introduce a method for the fabrication of highly conductive, low-porosity, flexible metal grid TCs
via
temperature-controlled direct imprinting (TCDI) of Ag ionic ink. The TCDI technique based on two-step heating is capable of not only stably capturing the Ag ionic ink, but also reducing the porosity of thermally decomposed Ag nanoparticle structures by eliminating large amounts of organic complexes. The porosity reduction of metal grid TCs on a glass substrate leads to a significant decrease of the sheet resistance from 21.5 to 5.5 Ω sq
−1
with an optical transmittance of 91% at λ = 550 nm. The low-porosity metal grid TCs are effectively embedded to uniform, thin and transparent polymer films with negligible resistance changes from the glass substrate having strong interfacial fracture energy (~8.2 J m
−2
). Finally, as the porosity decreases, the flexible metal grid TCs show a significantly enhanced electromechanical durability under bending stresses. Organic light‐emitting diodes based on the flexible metal grid TCs as anode electrodes are demonstrated.
Journal Article
Soft, skin-interfaced microfluidic systems with integrated immunoassays, fluorometric sensors, and impedance measurement capabilities
2020
Soft microfluidic systems that capture, store, and perform biomarker analysis of microliter volumes of sweat, in situ, as it emerges from the surface of the skin, represent an emerging class of wearable technology with powerful capabilities that complement those of traditional biophysical sensing devices. Recent work establishes applications in the real-time characterization of sweat dynamics and sweat chemistry in the context of sports performance and healthcare diagnostics. This paper presents a collection of advances in biochemical sensors and microfluidic designs that support multimodal operation in the monitoring of physiological signatures directly correlated to physical and mental stresses. These wireless, battery-free, skin-interfaced devices combine lateral flow immunoassays for cortisol, fluorometric assays for glucose and ascorbic acid (vitamin C), and digital tracking of skin galvanic responses. Systematic benchtop evaluations and field studies on human subjects highlight the key features of this platform for the continuous, noninvasive monitoring of biochemical and biophysical correlates of the stress state.
Journal Article
Current evidence and the potential role of proton beam therapy for hepatocellular carcinoma
2023
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death, and external beam radiation therapy has emerged as a promising approach for managing HCC. Proton beam therapy (PBT) offers dosimetric advantages over X-ray therapy, with superior physical properties known as the Bragg peak. PBT holds promise for reducing hepatotoxicity and allowing safe dose-escalation to the tumor. It has been tried in various clinical conditions and has shown promising local tumor control and survival outcomes. A recent phase III trial demonstrated the non-inferiority of PBT in local tumor control compared to current standard radiofrequency ablation in early-stage HCC. PBT also tended to show more favorable outcomes compared to transarterial chemoembolization in the intermediate stage, and has proven effective in-field disease control and safe toxicity profiles in advanced HCC. In this review, we discuss the rationale, clinical studies, optimal indication, and future directions of PBT in HCC treatment.
Journal Article
Clinical Outcome of Salvage Radiotherapy for Locoregional Clinical Recurrence After Radical Prostatectomy
by
Shim, Su Jung
,
Cho, Jaeho
,
Choi, Seo Hee
in
Aged
,
Androgen Antagonists - therapeutic use
,
Cancer surgery
2021
Objectives: To assess the clinical outcomes of prostate cancer patients treated with salvage radiotherapy (SRT) for locoregional clinical recurrence (CR) after radical prostatectomy (RP). Methods: Records of 60 patients with macroscopic locoregional recurrence after prostatectomy and referrals for SRT were retrospectively investigated in the multi-institutional database. The median radiation dose was 70.2 Gy. Biochemical failure was defined as the prostate-specific antigen (PSA) ≥ nadir + 2 or initiation of androgen deprivation therapy (ADT) for increased PSA. Results: Median recurrent tumor size was 1.1 cm and pre-radiotherapy PSA level was 0.4 ng/ml. At a median follow-up of 83.1-month after SRT, 7-year biochemical failure-free survival (BCFFS), locoregional failure-free survival (LRFFS), distant metastasis-free survival (DMFS), and overall survival (OS) were 67.0%, 89.7%, 83.6%, and 91.2%, respectively. Higher Gleason's scores were associated with unfavorable BCFFS, DMFS, and OS. Pre-SRT PSA ≥0.5 ng/ml predicted worse BCFFS, LRFFS, and DMFS. In multivariate analyses, a Gleason's score of 8 to 10 was associated with decreased BCFFS (hazard ratio [HR] 3.12, 95% confidence interval [CI] 1.11-8.74, P = .031) and OS (HR 17.72, 95% CI 1.75-179.64, P = .015), and combined ADT decreased the risks of distant metastasis (HR 0.18, 95% CI 0.04-0.92, P = .039). Two patients (3.3%) experienced late grade 3 urinary toxicity. Conclusions: SRT for locoregional CR after RP achieved favorable outcomes with acceptable long-term toxicities. Higher Gleason's scores and pre-radiotherapy PSA level were unfavorable prognostic variables. Combined ADT may decrease the risks of metastases.
Journal Article
The LRF transcription factor regulates mature B cell development and the germinal center response in mice
2011
B cells play a central role in immune system function. Deregulation of normal B cell maturation can lead to the development of autoimmune syndromes as well as B cell malignancies. Elucidation of the molecular features of normal B cell development is important for the development of new target therapies for autoimmune diseases and B cell malignancies. Employing B cell-specific conditional knockout mice, we have demonstrated here that the transcription factor leukemia/lymphoma-related factor (LRF) forms an obligate dimer in B cells and regulates mature B cell lineage fate and humoral immune responses via distinctive mechanisms. Moreover, LRF inactivation in transformed B cells attenuated their growth rate. These studies identify what we believe to be a new key factor for mature B cell development and provide a rationale for targeting LRF dimers for the treatment of autoimmune diseases and B cell malignancies.
Journal Article
A Mobile Robotic System for the Inspection and Repair of SG Tubes in NPPs
2016
The reliability and performance of a steam generator (SG) is one of the serious concerns in the operation of pressurized water nuclear power plants. Because of high levels of radiation, robotic systems have been used to inspect and repair SG tubes. In this paper, we present a mobile robotic system that positions the inspection and repair tools while hanging down from the tube sheets where the tubes are fixed. All of the driving mechanisms of the mobile robot are actuated by electric motors to start its works, providing that the electric power is prepared without the additional need for an on-site air services. A special tube-holding mechanism with a high holding force has been developed to prevent falling from the tube sheets, even in the case of an electric power failure. We have also developed a quick installation guide device that guides the mobile robot to desired initial positions in the tube sheet exactly and quickly, which helps to reduce the radiation exposure of human workers during the installation work. This paper also provides on-site experimental results and lessons learned.
Journal Article