• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.395-401
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• 1998

We have synthesized new platinum(II) analogs containing 1,2-diaminocyclohexane (dach) as a carrier ligand, 1,3-bis(diphenylphosphino) propane (DPPP) /1,2-bis(diphenylphosphino)ethane (DPPE) as a leaving group and nitrates to improve solubility. In the present study, the cytotoxicity of $[Pt(trans-l-dach)(DPPP)]\;2NO_3$ (KHPC-001) and $[Pt(trans-l-dach)(DPPE)]\;2NO_3$ (KHPC-002) was evaluated and compared on various P-388 cancer cell lines and porcine kidney cell line ($LLC-PK_1$). The new platinum complexes demonstrated high efficacy on P-388 mouse leukemia cell line as well as cisplatin-resistant (P-388/CDDP) and adriamycin-resistant (P-388/ADR) P-388 cell lines. The intracellular platinum content was measured by a flame atomic absorption spectrophotometer (FAAS), and it was comparable to the results of $IC_{50}$ of the three complexes on $LLC-PK_1$ and P-388/S cells, while only DPPE compound was accumulated in high volume in P-388/ADR and P-388/CDDP cells. While the DNA-interstrand cross-links of KHPC-001, KHPC-002 and cisplatin were similar on P-388/S leukemia cells, these new platinum complexes were much less DNA cross-linking to a kidney derived cell line, $LLC-PK_1$. These results indicate that KHPC-001 and KHPC-002 are a third-generation platinum complexes with potent antitumor activity and low nephrotoxicity.

• Composites Research
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• v.35 no.3
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• pp.153-160
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• 2022

Cellulose nanofibrils (CNF) based on wood pulp fibers are gained much attention as part of biocompatible hydrogels for biomedical applications such as tissue engineering scaffolds, biomedicine, and drug carrier. However, CNF hydrogels have relatively poor mechanical properties, impeding their applications requiring high mechanical integrity. In this work, we prepare 2,2,6,6-tetramethylipiperidin-oxyl (TEMPO) oxidated cellulose nanofibrils hydrogels mediated with metal cations, which form the metal-carboxylate coordination bonds for enhanced mechanical strength and toughness. We conduct the large amplitude oscillatory shear (LAOS) test and Live/dead cell assay for obtaining nonlinear viscoelastic parameters and cell viability, respectively. In particular, the cell proliferation and viability change depending on the type of metal salt, which also affected the rheological properties of the hydrogels.

• BMB Reports
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• v.39 no.4
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• pp.339-345
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• 2006

The blood-neural barrier (BNB), including blood-brain barrier (BBB) and blood-retinal barrier (BRB), is an endothelial barrier constructed by an extensive network of endothelial cells, astrocytes and neurons to form functional 'neurovascular units', which has an important role in maintaining a precisely regulated microenvironment for reliable neuronal activity. Although failure of the BNB may be a precipitating event or a consequence, the breakdown of BNB is closely related with the development and progression of CNS diseases. Therefore, BNB is most essential in the regulation of microenvironment of the CNS. The BNB is a selective diffusion barrier characterized by tight junctions between endothelial cells, lack of fenestrations, and specific BNB transporters. The BNB have been shown to be astrocyte dependent, for it is formed by the CNS capillary endothelial cells, surrounded by astrocytic end-foot processes. Given the anatomical associations with endothelial cells, it could be supposed that astrocytes play a role in the development, maintenance, and breakdown of the BNB. Therefore, astrocytes-endothelial cells interaction influences the BNB in both physiological and pathological conditions. If we better understand mutual interactions between astrocytes and endothelial cells, in the near future, we could provide a critical solution to the BNB problems and create new opportunities for future success of treating CNS diseases. Here, we focused astrocyte-endothelial cell interaction in the formation and function of the BNB.

• Parasites, Hosts and Diseases
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• v.48 no.1
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• pp.15-21
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• 2010

Astrocytes are the most abundant cells in the central nervous system that play roles in maintaining the blood-brain-barrier and in neural injury, including cerebral malaria, a severe complication of Plasmodium falciparum infection. Prostaglandin (PG) $D_2$ is abundantly produced in the brain and regulates the sleep response. Moreover, $PGD_2$ is a potential factor derived from P. falciparum within erythrocytes. Heme oxygenase-1 (HO-1) is catalyzing enzyme in heme breakdown process to release iron, carbon monoxide, and biliverdin/bilirubin, and may influence iron supply to the P. falciparum parasites. Here, we showed that treatment of a human astrocyte cell line, CCF-STTG1, with $PGD_2$ significantly increased the expression levels of HO-1 mRNA by RT-PCR. Western blot analysis showed that $PGD_2$ treatment increased the level of HO-1 protein, in a dose- and time-dependent manner. Thus, $PGD_2$ may be involved in the pathogenesis of cerebral malaria by inducing HO-1 expression in malaria patients.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.240-246
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• 2013

In heterogeneous networks, the almost blank subframes (ABS) for inter-cell interference coordination (ICIC), which can be protected from the CCI due to unutilized subframes (i.e., ABS) is proposed. However, the analytical model for ABS-based systems has not been fully studied yet. In this paper, we derive a new analytical model to evaluate the performance of ABS-based systems. In an analytic model, we assume that each carrier in multicarrier systems, such as in OFDMA, is subject to large-scale fading, which is independent of other carriers. As a performance measure, we present the cumulative distribution function (CDF) for the effective SINR. We show the accuracy of the analytical model via simulation results.

• Journal of Welding and Joining
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• v.14 no.6
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• pp.68-80
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• 1996

When a workpiece is to be arc welded around the outside corner, continuous welding without welding seam in the neighborhood of comer still remains a very difficult technique. Skilled welders weld comers by delicate“hand-eye coordination”while turning the workpiece manually, However, there is not a very clear solution to this problem in robotized arc welding process. In order to solve this problem, the coordination of a robot and a positioner with one or two axes is necessary. This paper presents a method of continuous welding around the corner of workpiece using the coordinated motion of a robot and a positioner. The positioner is either revolute jointed or prismatic jointed. In this paper, a clothoid curve is chosen for welding trajectory. The clothoid curve is excellent in connecting straight and curved weld-lines with good continuity and accommodates various welding conditions. By using this welding trajectory, the deceleration, which leads to widening of the melt and the heat affected zone, at comer area is reduced with strategic rotation of robot torch in coordination with a positioner providing smooth transition of welding torch orientation. Two types of special clothoid curves are developed for different weld slope conditions. These clothoid curves are applied to the case of linear and rotary Positioners at arc welding robot work-cell.

• Genomics & Informatics
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• v.8 no.2
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• pp.90-93
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• 2010

A-kinase-anchoring proteins (AKAPs) are scaffold proteins which compartmentalize protein kinase A (PKA, cAMP-dependent protein kinase) and other enzymes to specific subcellular sites. The spatiotemporal control of these enzymes by AKAPs is important for cellular function like cell growth and development etc. Hence, it is important to understand the basic function of AKAPs and their functional domains. However, diverse names, function, cellular localizations and many members of AKAPs increase difficulties when researchers search appropriate AKAPs for their experimental purpose. Nevertheless, there was no previous AKAPs-related database regardless of their important cellular functions and difficulty of finding appropriate AKAPs. So, we developed AKAPs database (AKAPDB), which contains their sequence information, functions and other information derived from prediction programs and other databases. Therefore, we propose that AKAPDB can be an important tool to researchers in the related fields. AKAPDB is available via the internet at http://plaza3.snu.ac.kr/akapdb/.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.399-405
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• 2000

We have synthesized a novel platinum (II) coordination complex containing trans-ι-1,2-diaminocyclohexane (DACH) as a carrier ligand and 1,2-bis (diphenylphosphino)ethane (DPPE) as a leaving group. In addition, nitrate was added to improve the water-solubility. A new series of [Pt (trans-ι-DACH) (DPPE)].2NO$_3$(PC) was evaluated for its cytotoxic activity on MKN-45 human gastric adenocarcinoma cells and normal primary cultured kidney cells. PC has demonstrated high levels of cytotoxicity against MKN-45/S, MKN-45/ADR and MKN-45/CDDP cells. The cytotoxicity of PC against rabbit proximal renal tubular cells, human renal cortical cells, and human renal cortical tissues, determined using the MTT assaying technique, the ($^3$H)-thymidine uptake and the glucose consumption tests, was found to be quite less than those of cisplatin. Based on these results, this novel platinum (II) coordination complex appears to be better for improving antitumor activities with low nephrotoxicity and is a valuable lead in the development of new clinically available anticancer chemotherapeutic agents.

• BMB Reports
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• v.56 no.11
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• pp.575-583
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• 2023

Mitochondria, fundamental cellular organelles that govern energy metabolism, hold a pivotal role in cellular vitality. While consuming dioxygen to produce adenosine triphosphate (ATP), the electron transfer process within mitochondria can engender the formation of reactive oxygen species that exert dual roles in endothelial homeostatic signaling and oxidative stress. In the context of the intricate electron transfer process, several metal ions that include copper, iron, zinc, and manganese serve as crucial cofactors in mitochondrial metalloenzymes to mediate the synthesis of ATP and antioxidant defense. In this mini review, we provide a comprehensive understanding of the coordination chemistry of mitochondrial cuproenzymes. In detail, cytochrome c oxidase (CcO) reduces dioxygen to water coupled with proton pumping to generate an electrochemical gradient, while superoxide dismutase 1 (SOD1) functions in detoxifying superoxide into hydrogen peroxide. With an emphasis on the catalytic reactions of the copper metalloenzymes and insights into their ligand environment, we also outline the metalation process of these enzymes throughout the copper trafficking system. The impairment of copper homeostasis can trigger mitochondrial dysfunction, and potentially lead to the development of copper-related disorders. We describe the current knowledge regarding copper-mediated toxicity mechanisms, thereby shedding light on prospective therapeutic strategies for pathologies intertwined with copper dyshomeostasis.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.101-101
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• 1997

As part of a drug discovery program to develope more effective platinum-based anticancer drugs, a series of platinum complexes trans -diaminocyclohexane platinum bi sdiphenylphosphino -ethane (KHPC-002) cis-diaminocyclohexane platinum bisdiphenylphosphino-ethane (KHPC-006) has been evaluated in vitro against 4 human carcinoma cell lines with those of cisplatin using a tetrazolium-based colorimetric assay (MTT assay). The cell lines were two human bladder carcinoma cell lines, HT-1197 and HT-1376, human colon carcinoma cell line, HCT-116, and prostate cancer cell line DU-145.