• Macromolecular Research
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• v.14 no.5
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• pp.573-578
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• 2006

Three different, polymer-platinum conjugates (hydrogels, microparticles, and nanoparticles) were synthesized by complexation of cis-dichlorodiammineplatinum(II) (cisplatin) with partially succinylated glycol chitbsan (PSGC). Succinic anhydride was used as a linker to introduce cisplatin to glycol chitosan (GC). Succinylation of GC was investigated systematically as a function of the molar ratio of succinic anhydride to glucosamine, the methanol content in the reaction media, and the reaction temperature. By controlling the reaction conditions, water-soluble, partially water-soluble, and hydrogel-forming PSGCs were synthesized, and then conjugated with cisplatin. The complexation of cisplatin with water-soluble PSGC via a ligand exchange reaction of platinum from chloride to the carboxylates induced the formation of nano-sized aggregates in aqueous media. The hydrodynamic diameters of PSGC/cisplatin complex nano-aggregates, as determined by light scattering, were 180-300 nm and the critical aggregation concentrations (CACs), as determined by a fluorescence technique using pyrene as a probe, were $20-30{\mu}g/mL$. The conjugation of cisplatin with partially water-soluble PSGC, i.e., borderline between water-soluble and water-insoluble PSGC, produced micro-sized particles $<500{\mu}m$. Cisplatin-complexed PSGC hydrogels were prepared from water-insoluble PSGCs. All of the cisplatin-incorporated, polymer matrices released platinum in a sustained manner without any significant initial burst, suggesting that they may all be useful as slow release systems for cisplatin. The release rate of platinum increased with the morphology changes from hydrogel through microparticle to nanoparticle systems.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.212-217
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• 1992

The thermodynamic parameters for the formation of gadolinium benzoate have been determined in the ionic medium of 0.1 M $NaClO_4$ at $25^{\circ}C$ in aqueous solution. The thermodynamic results indicate that the complex is stabilized by the excess entropy effect caused by the dehydration of reacting ions. The especially high stability of Gd(III)-benzoate compared to the monodentate ligand complexes might be ascribed to the conjugation effect of the benzene ring in the benzoate ligand. IR spectra show that benzoate anion acts as a bidentate ligand toward $Gd^{3+}$ to form a chelate ring in solid state. Magnetic susceptibility data of the compound were also obtained and well described by Curie-Weiss law in the temperature range 80${\sim}$300K.

• YAKHAK HOEJI
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• v.57 no.6
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• pp.400-405
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• 2013

In this study, we measured the complex efficiency of a physiologically active antibody, a chelator and radiosiotopes using the ESI-TOF/Ms system for develop good radiopharmaceuticals. For a precise measurement, TLC is a low accuracy method. Loading of same amount of sample is difficult for each test, and work to quantify accurately the results obtained through TLC cannot be afforded compared to the use of other analytical instruments. The method of analysis using a mass spectrometer is capable of a mass analysis of proteins for quantitative analysis. The conjugates of the chelator (CHX-A- DTPA) and the antibody (IgG) were separated through MWCO, and were analyzed using ESI-TOF and MALDI-TOF mass spectrometry. The analysis using MALDI-TOF is roughly divided into measurements on mass spectrometry. When conjugating a small molecular weight of CHX-A-DTPA and a large molecular weight of IgG, distinguishing the peak of the conjugate and the peak of IgG was difficult. However, an ESI-TOF mass spectrometer system is capable of an analysis of mass by decentralizing the IgG. It is utilized as a technique for measuring the metabolic processes during conjugation and the stability evaluation of radiopharmaceuticals. When establishing this technique, the accuracy of the overall radiophar-maceutical analysis is expected to be able to be improved.

• Journal of Acupuncture Research
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• v.26 no.2
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• pp.159-170
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• 2009

Backgrounds and Objectives: A fracture means a loss of continuity in the substance of bone. Bone differs from other musculoskeletal tissue due to its ability to repair and heal itself without leaving a scar. The cutter head has multinucleated osteoclast cells to resorb the dead bone. The tail, with its conical surface, is lined with osteoblast cells laying down new bone. The conjugation of fracture is a unique biological process regulated by a complex array of signaling molecules and proinflammatory cytokines. Pyritum, one of the important prescriptions in the oriental medicine, has been used for conjugation fracture. The purpose of this study is to evaluate the effects of administration of Pyritum on activation of osteoblast cells in human body & on tibia bone fracture in mice. Materials and Methods : Four weeks aged 30 female DBA mice were used for this study. They were divided three groups, normal group, control group(fracture elicitate mice: FE group) and experimental group(Pyritum administered mice group after fracture elicitation : PA group). Left tibia bones of mice in FE and PA groups were fractured by bone cutters. MG-63 cells in human body th Pyritum in the ratio of 1 mg/m${\ell}$, and the cells were further incubated for 24 hours. Activation of osteoblast was identified using osteopontin, FGF in vitro test. In vivo test, regeneration of fractured tibia through the morphological changes was observed, and also activation of inflammation through NF-${\kappa}$B p65, iNOS, COX-2, osteoblast through osteopontin, FGF and osteoblast's proliferation in each group was measured. Results and Conclusions : 1. In vitro test for activation of osteoblast cells in human body by Pyritum, osteopontin and FGF production were remarkably increased in Pyritum treated MG-63 cells. 2. In regeneration of fractured tibia by Pyritum, fractured area in external tibia morphology was decreased more in the PA group than that of the FE group. Osteogenesis in fractured area was increased more in the PA group than that of the FE group. Also, endochodrial ossification in central area of fracture and osteoid in lateral area of fracture were increased more in the PA group than those of the FE group. 3. In activation of inflammation by Pyritum administered, activation of NF-${\kappa}$B p65, increase of iNOS and COX-2 production were higher in the PA and the FE groups than those of the control group. Especially, the PA group showed higher activation and increase than those of the FE group. 4. In activation of osteoblast by Pyritum, increase of osteopontin, FGF and osteoblast's proliferation were higher in the PA and the FE groups than those of the control group. Especially, the PA group showed higher increase and proliferation than those of the FE group.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.116-124
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• 2012

Identification was performed in March 2008 for the 76 Enterococcus strains isolated from the Han-river, which is used as water supply for Seoul citizens. The antibiotic susceptibility, antibiotic resistant structural analysis, trans-conjugation, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were also carried out for the isolated strains. Among the isolated strains, 25 strains were E. casseliflavus, 4 strains were E. faecalis and 1 strain was E. hirae. Investigation of antibiotic susceptibility indicated that 15 strains demonstrated tolerance against vancomycin, and that 11 strains of E. faecium and 4 strains of E. casseliflavus were VRE. The vanA gene detection of the VRE strains revealed that 6 E. faecium strains were vancomycin-resistant Enterococcus faecium (VREF) possessing vanA. Analyses of transposon Tn1546 structure containing vanA demonstrated that Km36 and Km37 belonged to Tn1 type, Km20 and Km38 was Tn2 type, and Km39 and Km40 was Tn3 type. PFGE disclosed that among the 6 VREF strains, Km36 and Km37 exhibited equivalent subtype, while the rest 4 strains showed subtypes different to each other. MLST for the 6 VREF strains disclosed that 3 strains were ST78, while the rest 3 strains were ST18, ST192 and ST230, respectively. All these clonal complexes were derived from CC17 which has been isolated from clinical sources. 4 strains belonged to CC78, while the rest 2 strains were CC18 and CC192, respectively.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.398-406
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• 2022

The outer membrane of Gram-negative bacteria is the outermost layer of cellular environment in which numerous biophysical and biochemical processes are in action sustaining viability. Advances in cell engineering enable modification of bacterial genetic information that subsequently alters membrane physiology to adapt bacteria to specific purposes. Surface display of a functional molecule on the outer membranes is one of strategies that directs host cells to respond to a specific extracellular matter or stimulus. While intracellular expression of a functional peptide or protein fused to a membrane-anchoring motif is commonly practiced for surface display, the method is not readily applicable to exogenous or large proteins inexpressible in bacteria. Chemical conjugation at reactive groups naturally occurring on the membrane might be an alternative, but often compromises fitness due to non-specific modification of essential components. Herein, we demonstrated two distinct approaches that enable site-specific decoration of the outer membrane with a fluorescent agent in Escherichia coli. An unnatural amino acid genetically incorporated in a surface-exposed peptide could act as a chemoselective handle for bioorthogonal dye labeling. A surface-displayed α-helical domain originating from a part of a selected heterodimeric coiled-coil complex could recruit and anchor a green fluorescent protein tagged with a complementary α-helical domain to the membrane surface in a site- and hetero-specific manner. These methods hold a promise as on-demand tools to confer new functionalities on the bacterial membranes.