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1.
Clin Immunol ; 253: 109686, 2023 08.
Article in English | MEDLINE | ID: mdl-37414380

ABSTRACT

Inflammatory demyelinating disease of the CNS (IDD) is a heterogeneous group of autoimmune diseases, and multiple sclerosis is the most common type. Dendritic cells (DCs), major antigen-presenting cells, have been proposed to play a central role in the pathogenesis of IDD. The AXL+SIGLEC6+ DC (ASDC) has been only recently identified in humans and has a high capability of T cell activation. Nevertheless, its contribution to CNS autoimmunity remains still obscure. Here, we aimed to identify the ASDC in diverse sample types from IDD patients and experimental autoimmune encephalomyelitis (EAE). A detailed analysis of DC subpopulations using single-cell transcriptomics for the paired cerebrospinal fluid (CSF) and blood samples of IDD patients (total n = 9) revealed that three subtypes of DCs (ASDCs, ACY3+ DCs, and LAMP3+ DCs) were overrepresented in CSF compared with their paired blood. Among these DCs, ASDCs were also more abundant in CSF of IDD patients than in controls, manifesting poly-adhesional and stimulatory characteristics. In the brain biopsied tissues of IDD patients, obtained at the acute attack of disease, ASDC were also frequently found in close contact with T cells. Lastly, the frequency of ASDC was found to be temporally more abundant in acute attack of disease both in CSF samples of IDD patients and in tissues of EAE, an animal model for CNS autoimmunity. Our analysis suggests that the ASDC might be involved in the pathogenesis of CNS autoimmunity.


Subject(s)
Encephalomyelitis, Autoimmune, Experimental , Multiple Sclerosis , Animals , Humans , T-Lymphocytes , Brain/pathology , Dendritic Cells , Antigens, Differentiation, Myelomonocytic , Antigens, CD , Lectins
2.
Anal Biochem ; 571: 40-48, 2019 04 15.
Article in English | MEDLINE | ID: mdl-30797744

ABSTRACT

Sialylation can influence the stability, half-life, and immunogenicity of glycoproteins, but sialylated N-glycans are known to be difficult to analyze. Human alpha1-acid glycoprotein (AGP) is reported to have glycans that consist of sialylated N-glycans. The N-glycan profiling of AGP is qualitatively and quantitatively investigated here by UPLC and LC-ESI-MS/MS. Three fluorescent tags (AB, AA, and ProA) and two separation columns (HILIC and AEX-HILIC) were adopted to confirm and compare each analytical characteristic. The results of AA were comparable to those of the well-established AB. The qualification of ProA was notable due to its superior fluorescence intensity and ionization efficiency, and ProA showed smaller quantitative or larger-sized fragments in LC-ESI-MS/MS compared to AB and AA. However, the MS quantification of ProA was distorted because the increased sialylation level decreased the LC-ESI-MS/MS ionization efficiency. HILIC had better peak separability, AEX-HILIC had an advantage in UPLC sialylation profiling, and each isomeric glycan could be identified by both columns in LC-ESI-MS/MS. In conclusion, ProA is favored for UPLC and LC-ESI-MS/MS detection but not reliable for MS quantification. This study firstly demonstrates the qualification and quantification of sialylated N-glycans by comparing the commonly used analytical conditions with different fluorescent tags, columns, and instruments.


Subject(s)
Fluorescent Dyes/chemistry , Polysaccharides/analysis , Sialic Acids/analysis , Chromatography, Liquid , Fluorescent Dyes/analysis , Glycoproteins/chemistry , Humans , Spectrometry, Mass, Electrospray Ionization , Tandem Mass Spectrometry
3.
Biochem Biophys Res Commun ; 495(4): 2418-2424, 2018 01 22.
Article in English | MEDLINE | ID: mdl-29274340

ABSTRACT

Myozyme is a recombinant human acid alpha-glucosidase (rhGAA) that is currently the only drug approved for treating Pompe disease, and its low efficacy means that a high dose is required. Mannose-6-phosphate (M6P) glycosylation on rhGAA is a key factor influencing lysosomal enzyme targeting and the efficacy of enzyme replacement therapy (ERT); however, its complex structure and relatively small quantity still remain to be characterized. This study investigated M6P glycosylation on rhGAA using liquid chromatography (LC)-electrospray ionization (ESI)-high-energy collisional dissociation (HCD) tandem mass spectrometry (MS/MS). The glycans released from rhGAA were labeled with procainamide to improve mass ionization efficiency and the sensitivity of MS/MS. The relative quantities (%) of 78 glycans were obtained, and 1.0% of them were glycans containing M6P (M6P glycans). These were categorized according to their structure into 4 types: 3 newly found ones, comprising high-mannose-type M6P glycans capped with N-acetylglucosamine (GlcNAc) (2 variants, 17.5%), hybrid-type M6P glycans (2 variants, 11.2%), and hybrid-type M6P glycans capped with GlcNAc (3 variants, 6.9%), as well as high-mannose-type M6P glycans (3 variants, 64.4%). HCD-MS/MS spectra identified six distinctive M6P-derived oxonium ions. The glycopeptides obtained from protease-digested rhGAA were analyzed using nano-LC-ESI-HCD-MS/MS, and the extracted-ion chromatograms of M6P-derived oxonium ions confirmed three M6P glycosylation sites comprising Asn 140, Asn 233 (newly found), and Asn 470 attached heterogeneously to nine M6P glycans (two types), eight M6P glycans (four types), and seven M6P glycans (two types), respectively. This is the first study of rhGAA to differentiate M6P glycans and identify their attachment sites, despite rhGAA already being an approved drug for Pompe disease.


Subject(s)
Glycogen Storage Disease Type II/drug therapy , Mannosephosphates/chemistry , Mannosephosphates/therapeutic use , Polysaccharides/chemistry , Polysaccharides/therapeutic use , alpha-Glucosidases/chemistry , alpha-Glucosidases/therapeutic use , Binding Sites , Drug Approval , Humans , Protein Binding , Recombinant Proteins/chemistry , Recombinant Proteins/therapeutic use
4.
Ann Plast Surg ; 78(4): 365-370, 2017 Apr.
Article in English | MEDLINE | ID: mdl-27740951

ABSTRACT

BACKGROUND: The ability to correct unnatural-appearing, high, and deep double eyelid folds has been limited by the lack of redundant upper eyelid skin and the presence of prior incision line scars in patients. METHODS: From January 2000 to September 2011, 256 patients with high and deep double eyelid folds underwent our fold-lowering procedure. The first dissection was made at the superficial layer between the orbicularis oculi muscle and orbital septum/retroorbicularis oculi fat. The second dissection was at a deeper layer between the preaponeurotic fat and levator aponeurosis. The dissection proceeded 7 to 8 mm farther cephalad to the prior fold line to separate the upper flap and the floor from the prior fold line. The lower flap was undermined caudally to obtain normal skin tension, and the lower flap was secured to the septoaponeurosis junctional thickening or pretarsal tissue. Six months after surgery, the correction of the high fold scar and change in fold height (with eyes closed) was documented. RESULTS: Using the authors' technique, unnatural-appearing, high, and deep double eyelid folds were converted to lower nondepressed folds. Although prior high fold incision scars could be seen postoperatively on close examination, they were not easily visible. Complications included fold height asymmetry in 10 cases, persistence of the prior fold in 5 cases, and redundant upper flap skin that needed further excision in 25 cases. CONCLUSIONS: Using a wide double-layer dissection, high folds were lowered successfully even in situations where there was no redundant upper eyelid skin for excision.


Subject(s)
Blepharoplasty/methods , Dissection/methods , Eyelids/surgery , Surgical Flaps/transplantation , Wound Healing/physiology , Adult , Asian People/statistics & numerical data , Cohort Studies , Esthetics , Female , Humans , Male , Middle Aged , Patient Satisfaction/statistics & numerical data , Postoperative Care/methods , Republic of Korea , Retrospective Studies , Risk Assessment
5.
Immunology ; 143(4): 550-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-24913005

ABSTRACT

The roles of Notch1 and Notch2 in T-cell function have been well studied, but the functional roles of Notch in B cells have not been extensively investigated, except for Notch2 involvement in peripheral marginal zone B-cell differentiation. This study examined the roles of Notch1 in murine primary B cells. During B-cell activation by B-cell receptor ligation, Notch1 was up-regulated while Notch2 was not. In addition, Notch1 up-regulation itself did not contribute to the further activation of B cells, but the Notch ligand was important for Notch1-mediated further B-cell activation. Moreover, Notch1 deficiency significantly decreased B-cell activation and antibody secretion under the presence of Notch ligand. These data suggest that Notch1 is an important mediator for enhancing B-cell activation and antibody secretion by Notch ligand.


Subject(s)
Antibody Formation/genetics , Antibody Formation/immunology , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , Lymphocyte Activation/immunology , Receptor, Notch1/metabolism , Animals , B-Lymphocytes/cytology , Cell Differentiation/genetics , Cell Line , Gene Deletion , Gene Expression , Gene Knockout Techniques , Humans , Ligands , Lymphocyte Activation/genetics , Mice , Phenotype , Protein Interaction Domains and Motifs , Receptor, Notch1/agonists , Receptor, Notch1/chemistry , Receptor, Notch1/genetics , Receptors, Antigen, B-Cell/metabolism
6.
Nanoscale ; 16(11): 5613-5623, 2024 Mar 14.
Article in English | MEDLINE | ID: mdl-38412042

ABSTRACT

Modern silicone-based epidermal electronics engineered for body temperature sensing represent a pivotal development in the quest for advancing preventive medicine and enhancing post-surgical monitoring. While these compact and highly flexible electronics empower real-time monitoring in dynamic environments, a noteworthy limitation is the challenge in regulating the infiltration or obstruction of heat from the external environment into the surface layers of these electronics. The study presents a cost-effective temperature sensing solution by embedding wireless electronics in a multi-layered elastomeric composite to meet the dual needs of enhanced thermal insulation for encapsulation in contact with air and improved thermal conductivity for the substrate in contact with the skin. The encapsulating composite benefits from the inclusion of hollow silica microspheres, which reduce the thermal conductivity by 40%, while non-spherical aluminum nitride enhances the thermal conductivity of the substrate by 370%. The addition of particles to the respective composites inevitably leads to an increase in modulus. Two composite elements are engineered to coexist while maintaining a matching low modulus of 3.4 MPa and a stretchability exceeding 30%, all without compromising the optimized thermal properties. Consecutive thermal, electrical, and mechanical characterization confirms the sensor's capacity for precise body temperature monitoring during a single day's lifespan, while also assessing the influence of behavioral factors on body temperature.

7.
Gut Microbes ; 15(1): 2226915, 2023.
Article in English | MEDLINE | ID: mdl-37351626

ABSTRACT

Age-related gut microbes and urine metabolites were investigated in 568 healthy individuals using metataxonomics and metabolomics. The richness and evenness of the fecal microbiota significantly increased with age, and the abundance of 16 genera differed between the young and old groups. Additionally, 17 urine metabolites contributed to the differences between the young and old groups. Among the microbes that differed by age, Bacteroides and Prevotella 9 were confirmed to be correlated with some urine metabolites. The machine learning algorithm eXtreme gradient boosting (XGBoost) was shown to produce the best performing age predictors, with a mean absolute error of 5.48 years. The accuracy of the model improved to 4.93 years with the inclusion of urine metabolite data. This study shows that the gut microbiota and urine metabolic profiles can be used to predict the age of healthy individuals with relatively good accuracy.


Subject(s)
Gastrointestinal Microbiome , Microbiota , Humans , Child, Preschool , Feces , Metabolomics , Machine Learning , RNA, Ribosomal, 16S
8.
Sci Rep ; 12(1): 11248, 2022 Jul 04.
Article in English | MEDLINE | ID: mdl-35787663

ABSTRACT

In this study, numerical analysis was performed to predict amount of fragments and travel distance after collision of a concrete median barrier with a truck under impact loading using Smooth Particle Hydrodynamics (SPH). The obtained results of the SPH analysis showed that amount of fragments and the travel distance can be changed depending on different velocity-to-mass ratios under same local impact energy. Using the results of the SPH analysis, artificial neural network (ANN) was constructed to consider the uncertainties for the prediction of amount of fragments and travel distance of concrete after collision. In addition, the results of the ANN were compared with the results of multiple linear regression analysis (MRA). The ANN results showed better coefficient of determination (R2) than the MRA results. Therefore, the ANN showed improvement than the MRA results in terms of the uncertainties of the prediction of amount of fragments and travel distance. Using the constructed ANN, data augmentation was conducted from a limited number of analysis data using a statistical distribution method. Finally, the fragility curves of the concrete median barrier were suggested to estimate the probability of exceed specific amount of fragments and travel distance under same impact energy.

9.
Materials (Basel) ; 15(9)2022 May 01.
Article in English | MEDLINE | ID: mdl-35591594

ABSTRACT

In the present study, graphite blocks were fabricated using synthetic graphite scrap and phenolic resin, and the effect of the heating rate during carbonization on their mechanical and electrical characteristics was examined. While varying the heating rate from 1, 3, 5, and 7 to 9 °C/min, the microstructure, density, porosity, flexural strength, compressive strength, and electrical resistivity of the fabricated graphite blocks were measured. As the heating rate increased, the pores in the graphite blocks increased in size, and the shape of the gas release paths became more irregular. Overall, it was found that increases in the heating rate led to the degradation of the graphite blocks' mechanical and electrical properties.

10.
Materials (Basel) ; 15(3)2022 Jan 28.
Article in English | MEDLINE | ID: mdl-35160990

ABSTRACT

In the present study, the amount of fragments generated and their travel distances due to vehicle collision with concrete median barrier (CMB) was analyzed and predicted. In this regard, machine learning was applied to the results of numerical analysis, which were developed by comparing with field test. The numerical model was developed using smoothed particle hydrodynamics (SPH). SPH is a mesh-free method that can be used to predict the amount of fragments and their travel distances from concrete structures under impact loading. In addition, deep neural network (DNN) and gradient boosting machine (GBM) were also employed as machine learning methods. In this study, the results of DNN, GBM, and numerical analysis were then compared with the conducted field test. Such comparisons revealed that numerical analysis generated lower error than both DNN and GBM. When prediction results of both the amount of fragments and their travel distances were considered, the result of DNN showed smaller errors than that of GBM. Therefore, in studies where machine learning is used to predict the amount of fragments and their travel distances, careful selection of an appropriate method from the various available machine learning methods such as DNN, GBM, and random forest is absolutely important.

11.
Front Physiol ; 13: 1054463, 2022.
Article in English | MEDLINE | ID: mdl-36505084

ABSTRACT

Exercise and obesity regulate hematopoiesis, in part through alterations in cellular and soluble components of the bone marrow niche. Extracellular vesicles (EVs) are components of the bone marrow niche that regulate hematopoiesis; however, the role of exercise training or obesity induced EVs in regulating hematopoiesis remains unknown. To address this gap, donor EVs were isolated from control diet-fed, sedentary mice (CON-SED), control diet-fed exercise trained mice (CON-EX), high fat diet-fed, sedentary mice (HFD-SED), and high fat diet-fed, exercise trained mice (HFD-EX) and injected into recipient mice undergoing stress hematopoiesis. Hematopoietic and niche cell populations were quantified, and EV miRNA cargo was evaluated. EV content did not differ between the four groups. Mice receiving HFD-EX EVs had fewer hematopoietic stem cells (HSCs) (p < 0.01), long-term HSC (p < 0.05), multipotent progenitors (p < 0.01), common myeloid progenitors (p<0.01), common lymphoid progenitors (p < 0.01), and granulocyte-macrophage progenitors (p < 0.05), compared to mice receiving HFD-SED EVs. Similarly, mice receiving EX EVs had fewer osteoprogenitor cells compared to SED (p < 0.05) but enhanced mesenchymal stromal cell (MSC) osteogenic differentiation in vitro (p < 0.05) compared to SED EVs. HFD EVs enhanced mesenchymal stromal cell (MSC) adipogenesis in vitro (p < 0.01) compared to CON EVs. HFD-EX EVs had lower microRNA-193 and microRNA-331-5p content, microRNAs implicated in inhibiting osteogenesis and leukemic cell expansion respectively, compared to HFD-SED EVs. The results identify alterations in EV cargo as a novel mechanism by which exercise training alters stress hematopoiesis and the bone marrow niche.

12.
Materials (Basel) ; 14(14)2021 Jul 17.
Article in English | MEDLINE | ID: mdl-34300924

ABSTRACT

The effect of a magnetic field on the rheology of mortars with steel slags and fibers was evaluated in this study. The rheology of the mortar measured with and without a magnetic field was compared. The effect of steel fiber addition to normal and steel slag mortars, mix ratio and size of steel fibers, and magnetic field formation position on rheology were evaluated. Steel fiber addition increased the yield stress and viscosity of the normal and steel slag mortars. The increased rheology was almost restored because of the magnetic field applied to the normal mortars. However, the increased rheology of the steel slag mortars with steel fibers was restored only upon the application of the magnetic field, whose position was continuously changed by a power relay. It is deduced that the alignment of the steel fibers by the magnetic field contributes to the rheology reduction of the mortars. However, in the case of steel slag mortar, experimental results demonstrated that steel slag, which is a ferromagnetic material, receives constant force by the magnetic field, which increases the rheology. This is evidenced by the decrease in the rheology of steel slag mortars under a continuously changing magnetic field formation position by power relay.

13.
Materials (Basel) ; 14(16)2021 Aug 14.
Article in English | MEDLINE | ID: mdl-34443088

ABSTRACT

We firstly introduce Er and Ga co-doped swedenborgite-structured YBaCo4O7+δ (YBC) as a cathode-active material in lithium-ion batteries (LIBs), aiming at converting the phase instability of YBC at high temperatures into a strategic way of enhancing the structural stability of layered cathode-active materials. Our recent publication reported that Y0.8Er0.2BaCo3.2Ga0.8O7+δ (YEBCG) showed excellent phase stability compared to YBC in a fuel cell operating condition. By contrast, the feasibility of the LiCoO2 (LCO) phase, which is derived from swedenborgite-structured YBC-based materials, as a LIB cathode-active material is investigated and the effects of co-doping with the Er and Ga ions on the structural and electrochemical properties of Li-intercalated YBC are systemically studied. The intrinsic swedenborgite structure of YBC-based materials with tetrahedrally coordinated Co2+/Co3+ are partially transformed into octahedrally coordinated Co3+, resulting in the formation of an LCO layered structure with a space group of R-3m that can work as a Li-ion migration path. Li-intercalated YEBCG (Li[YEBCG]) shows effective suppression of structural phase transition during cycling, leading to the enhancement of LIB performance in Coulombic efficiency, capacity retention, and rate capability. The galvanostatic intermittent titration technique, cyclic voltammetry and electrochemical impedance spectroscopy are performed to elucidate the enhanced phase stability of Li[YEBCG].

14.
Micromachines (Basel) ; 12(8)2021 Aug 06.
Article in English | MEDLINE | ID: mdl-34442555

ABSTRACT

Although skin-like pressure sensors exhibit high sensitivity with a high performance over a wide area, they have limitations owing to the critical issue of being linear only in a narrow strain range. Various strategies have been proposed to improve the performance of soft pressure sensors, but such a nonlinearity issue still exists and the sensors are only effective within a very narrow strain range. Herein, we fabricated a highly sensitive multi-channel pressure sensor array by using a simple thermal evaporation process of conducting nanomembranes onto a stretchable substrate. A rigid-island structure capable of dissipating accumulated strain energy induced by external mechanical stimuli was adopted for the sensor. The performance of the sensor was precisely controlled by optimizing the thickness of the stretchable substrate and the number of serpentines of an Au membrane. The fabricated sensor exhibited a sensitivity of 0.675 kPa-1 in the broad pressure range of 2.3-50 kPa with linearity (~0.990), and good stability (>300 Cycles). Finally, we successfully demonstrated a mapping of pressure distribution.

15.
Enzyme Microb Technol ; 134: 109482, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32044029

ABSTRACT

Recombinant human acid alpha-glucosidase (rhGAA) from Chinese hamster ovary cells is the only approved treatment for patients with Pompe disease. In this study, rhGAAs were produced in transgenic rice cell suspension cultures under eight different conditions; untreated, 5 µM of 2-fluoro-l-fucose (2-FF), 50 µM of 2-FF, 100 µM of 2-FF, 100 µM of 2-FF + 0.5% Pluronic F-68 (PF-68), 100 µM of 2-FF + 0.05% Tween 20 (Tw 20), 0.5% PF-68, and 0.05% Tw 20. The N-glycans of eight rhGAAs were analyzed using ultra-performance liquid chromatography (UPLC) and tandem mass spectrometry. The relative quantity (%) of each glycan was obtained from the corresponding UPLC peak area per the sum (100%) of individual UPLC peak area. Fifteen N-glycans, comprising seven core-fucosylated glycans (71.5%, sum of each relative quantities) that have immunogenicity-inducing potential, three de-core-fucosylated glycans (15.4%), and five non-core-fucosylated glycans (13.1%), were characterized with high mass accuracy and glycan-generated fragment ions. The increases or decreases of relative quantities of each glycan from seven rhGAAs were compared with those of untreated control. The percentages of the sum of the relative quantities of core-fucosylated glycans divided by the sums of those of de-core- (core-fucose removed) and non-core-fucosylated glycans were calculated, and the lowest percentage was obtained in 100 µM of 2-FF combined with 0.5% PF-68. These results indicate that the relative quantity of each glycan of rhGAA produced in rice cell suspension cultures is significantly affected by their culture condition. This study performed the comparison of the N-glycan profiles of rice cell-derived rhGAA to identify the core-fucosylated glycans using UPLC and tandem mass spectrometry.


Subject(s)
Oryza/genetics , Polysaccharides/chemistry , alpha-Glucosidases/biosynthesis , Animals , CHO Cells , Cell Culture Techniques , Chromatography, Liquid , Cricetulus , Fucose/chemistry , Humans , Oryza/cytology , Plants, Genetically Modified , Recombinant Proteins/biosynthesis , Tandem Mass Spectrometry , alpha-Glucosidases/genetics
16.
Materials (Basel) ; 12(20)2019 Oct 15.
Article in English | MEDLINE | ID: mdl-31618816

ABSTRACT

The lack of ductility is the greatest concern in the applications of carbon fiber reinforced polymer (CFRP) materials, when used as pre-stressing reinforcements. To improve the ductility, a partially bonded FRP system which is intentionally unbonded in the middle part of the beam and bonded in both end parts of the beam has been developed and applied to prestressed concrete beams. While, many researchers investigated the instantaneous performance of partially bonded CFRP prestressed concrete beams, this study intended to evaluate the fatigue performance, the static load-carrying capacity after fatigue loading and ductility. Based on the fatigue loading tests followed by static loading tests, over-reinforced and web-confined partially bonded CFRP prestressed concrete beams exhibited satisfactory fatigue performance without cracks and stiffness degradation during fatigue loading. In addition, no degradation of load-carrying capacity was observed in static loading tests after the fatigue tests. The ductility index of concrete beams, prestressed with partially bonded CFRP bars, is combined with over-reinforcements and web-confinements, similar to that of beams prestressed with steel bars.

17.
Materials (Basel) ; 12(19)2019 Sep 27.
Article in English | MEDLINE | ID: mdl-31569779

ABSTRACT

In South Korea, the number of vehicles is gradually increasing. The number of heavy vehicles in 2010 increased up to 19% in less than five years. Therefore, the chances of heavy vehicle-concrete median barrier (CMB) collision also became higher than in the past; therefore, a need to study a stricter design level for improving the current CMB (CMB-15) under harsher environments arose. Accordingly, in the present study, a new concrete median barrier was designed under a stricter impact severity, SB6(420 kJ), compared to the current design impact severity, SB5-B (270 kJ). In particular, shock absorbing devices to absorb impact energy were applied to the CMB. An empty space allows the dowel bars to deform and absorb collision energy. Therefore, deformable CMB was designed and tested. The key parameters selected in our study were dowel bar and wire-mesh. A series of numerical analyses were conducted to evaluate the proposed new deformable CMB designs with shock absorbers. Finally, the optimal design, CMB-17S, was proposed after several evaluations of the proposed designs and a full-scale field test. It was found that, although the developed model did not accurately predict the impact sequence due to certain differences between the actual truck and the truck model, the permanent deformation after collision could be well predicted. Based on the observations from a full-scale impact test, it was recommended that the top part of the CMB should be strengthened since major volume loss occurred due to local impact, which appeared to be due to punching shear failure.

18.
J Pharm Biomed Anal ; 169: 188-195, 2019 May 30.
Article in English | MEDLINE | ID: mdl-30877930

ABSTRACT

O-acetylated sialic acid (SA) attached to the N-glycans of therapeutic glycoproteins reportedly inhibit sialidase activity, increase protein half-life, decrease protein antigenicity, and stabilize protein conformation. Recombinant human acid α-glucosidase (Myozyme) is the only drug approved by the United States Food and Drug Administration for the treatment of Pompe disease. In this study, unreported N-glycans containing O-acetylated SA in Myozyme and the relative quantities of total glycans were investigated using liquid chromatography (LC)-electrospray ionization (ESI)-high-energy collisional dissociation (HCD) tandem mass spectrometry (MS/MS). The 17 N-glycans (6.4% of total glycans) containing mono-, di-, mono/di-, and di/di-O-acetylated N-acetylneuraminic acid (Neu5Ac) were identified with mass accuracy, glycan-generated fragment ions, and the retention time on an LC column. The analysis of peptides containing mono- and/or di-O-acetylated Neu5Ac ions sorted from all peptides using nano-LC-ESI-HCD-MS/MS confirmed six O-acetylation sites (Asn 140, Asn 233, Asn 390, Asn 470, Asn 652, and Asn 882), at least five of which (Asn 140, Asn 233, Asn 390, Asn 470, and Asn 652) could contribute to the drug efficacy or cellular uptake of Myozyme. This is the first study to identify N-glycans containing O-acetylated Neu5Ac and O-acetylation sites in Myozyme.


Subject(s)
Polysaccharides/chemistry , alpha-Glucosidases/chemistry , Acetylation , Chromatography, Liquid/methods , Glycoproteins/chemistry , Humans , N-Acetylneuraminic Acid/chemistry , Peptides/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Tandem Mass Spectrometry/methods
19.
Int J Biol Macromol ; 138: 1072-1078, 2019 Oct 01.
Article in English | MEDLINE | ID: mdl-31325506

ABSTRACT

Bovine submaxillary mucin (BSM) is a heavily-glycosylated macromolecular (approximately 4 MDa) protein and is used in various biomaterial applications in light of its high viscosity and biocompatibility, in addition to use as a biochemical substrate or inhibitor as a result of its abundant O-glycans. Although it has been reported that N-glycosylation provides stability of human mucins, most BSM research has been focused on its O-glycans, while N-glycans have not been reported to date. In this study, a common N-glycan core component was detected by monosaccharide analysis of BSM, and the structures of the N-glycans and their relative quantities were determined by liquid chromatography-tandem mass spectrometry. Seventeen N-glycans comprising ten complex-type [Fucose0~2Hexose3~4N-acetylhexosamine1~6Sulfate0~1; 61.1% (the sum of the relative quantities of each N-glycan out of the total N-glycans)], two high-mannose-type (Hexose5~6N-acetylhexosamine2; 12.0%), and five paucimannose type (Fucose0~1Hexose3~4N-acetylhexosamine2~3; 26.9%) were identified, but no hybrid-type or sialylated N-glycans were found. Additionally, these are less-branched structures compared to human mucins. Of these, ten glycans (77.2%), including two sulfated glycans (8.0%), were core fucosylated, which confer unique biological functions to glycoproteins. The N-glycosylation sites were identified from the analysis of glycopeptides from BSM. This study is the first confirmation of N-glycan attachment to BSM.


Subject(s)
Mucins/chemistry , Polysaccharides/chemistry , Animals , Cattle , Chromatography, Liquid , Glycosylation , Monosaccharides/chemistry , Spectrometry, Mass, Electrospray Ionization , Submandibular Gland/metabolism , Tandem Mass Spectrometry
20.
IEEE Trans Appl Supercond ; 18(2): 912-915, 2008.
Article in English | MEDLINE | ID: mdl-20390056

ABSTRACT

A 700-mm bore superconducting magnet was built and operated in our laboratory to demonstrate the feasibility of newly developed MgB(2) superconductor wire for fabricating MRI magnets. The magnet, an assembly of 10 coils each wound with a reacted and s-glass insulated wire ~1-km long, was immersed in solid nitrogen rather than in a bath of liquid cryogen. This MgB(2) magnet was designed to operate in the temperature range 10-15 K, maintained by a cryocooler. A combination of this "wide" temperature range and immersion of the winding in solid nitrogen enables this magnet to operate under conditions not possible with a low temperature superconductor (LTS) counterpart. Tested individually at 13 K, each coil could carry current up to 100 A. When assembled into the magnet, some coils, however, became resistive, causing the magnet to prematurely quench at currents ranging from 79 A to 88 A, at which point the magnet generated a center field of 0.54 T. Despite the presence of a large volume (50 liters) of solid nitrogen in the cold body, cooldown from 77 K to 10 K went smoothly.

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