• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.4
• /
• pp.2401-2406
• /
• 2013

From January 1, 2008 to March 31, 2010, 101 patients with stage II-III breast cancer were enrolled in this study and subjected to an anthracycline-based neoadjuvant chemotherapy regimen with or without docetaxel. Surgery was performed after 2-6 cycles of chemotherapy, and the clinical response was determined by pathological and histochemical assessments. The clinical response rate, as indicated by complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD), were 6.9, 52.5, 36.6, and 4.0%, respectively. A multivariable correlation analysis indicated that the overall clinical response rate correlated with the number of metastatic lymph nodes, number of chemotherapy cycles, and vessel invasion status. Importantly, the CR rate was only associated with the number of chemotherapy cycles. Nonparametric tests failed to detect a correlation between HER2 or Topo $II{\alpha}$ status and clinical response to neoadjuvant chemotherapy in these patients. When they were stratified by HER2 or HR status, for HER2-positive patients the CR rate was associated with vessel invasion and Topo $II{\alpha}$ status. Based on our findings, we propose that HR, HER-2 and Topo $II{\alpha}$ are not putative predictive biomarkers of chemotherapy outcome for breast cancer patients. Topo $II{\alpha}$ expression level was only inversely correlated with CR rate among HR-positive patients. Importantly, the achievement of CR was largely related to the number of chemotherapy cycles.

• YAKHAK HOEJI
• /
• v.53 no.4
• /
• pp.222-227
• /
• 2009

Human topoisomerase I (Topo I) plays a pivotal role in cell replication, transcription and repair and, therefore, is an important anti-cancer target. 20S-camptothecin (CPT) is a representative Topo I inhibitor. Compounds belonging to CPT family inhibit the religation step of Topo I-DNA by binding to the DNA cleavage site. Computational docking studies with Surflex-Dock were carried out to investigate the binding modes between Topo I-DNA binary complex structure and the ligand such as 20S-CPT and 9,10-substituted 20S-CPT analogues. The docking results demonstrated that most of the compounds with $IC_{50}$ value under $0.5{\mu}M$ intercalated exactly between the -1 and +1 DNA bases, deeply toward the cleavage site. The complex was stabilized by hydrogen-bonding and hydrophobic interactions with both the enzyme and the DNA. The compounds with $IC_{50}$ value above $0.5{\mu}M$ were poorly docked and did not intercalate. In addition, the docking results confirmed the overall correlation between the $IC_{50}$ values and docking scores, indicating the possible use of the modeling for the prediction of biological activity and design of potential inhibitors.

• The Korean Journal of Zoology
• /
• v.36 no.3
• /
• pp.367-372
• /
• 1993

We have found a protein kinase activity that is tightly associated with type II DNA topoisomerase purified from regenerating rat liver. The activities of protein kinase and topoisomerase II were not separable when the enzyme was subjected to analytical chromatographies (Hydroxyapatite, phosphocellulose, and double strand DNA cellulose) and glycerol gradient sedimentation. The kinase activity from purified rat topoisomerase II was also inactivated by the topoisomerase II inhibitors such as N-ethylmaleimide or novobiocin. The evidences, however, do not rule out a possibility that the kinase activity resides in a polypeptide other than the topoisomerase II protein. The topoisomerase II-associated protein kinase required Mg++ for its activity, and this requirement was not substituted by any other mono- or divalent ions. Histone H1 act as a strong stimulator and a good substrate for the kinase activity and other histones and ${\alpha}$-casein could not substitute the effect of histone H1.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.10
• /
• pp.1960-1964
• /
• 2008

The roles of coordinating ligands (TOPO, OA, HDA, and TDPA) for the synthesis of ZnO nanoparticles are investigated. Various shapes (hexagonal cone, hexagonal plate, and rod) and sizes (5-100 nm) of ZnO nanoparticles are prepared in relation to the coordinating ligands. The hexagonal shapes ($\leq$ 100 nm) are synthesized with TOPO and OA, while smaller size nanorods (5 ${\times}$ 30 nm) are with TOPO and TDPA. The relative intensities of two distinctive emission bands centered at 385 and 500 nm, which are related to the exciton and defect states, respectively, depend on the crystal qualities of ZnO nanoparticles affected by the coordinating ligands. The intense UV emissions with the reduced visible emissions are found in the monodisperse nanoparticles such as hexagonal cones and nanorods, suggesting that the monodispersity as well as the crystallinity is closely related to the coordinating ligands. The blue-shift of photoluminescence and absorption edge is observed in the nanorods, because the sizes of the nanorods are in the quantum confinement regime.

• Journal of the Korean Chemical Society
• /
• v.39 no.2
• /
• pp.28-81
• /
• 1995

Inductively coupled plasma atomic emission spectrometry was used for the determination of all 14 rare earth elements (REE) in geological materials. Samples were decomposed by using acid digestion followed by alkaline fusion. Group separation of the REE was achieved by solvent extraction with TOPO (trioctylphosphine oxide) and back extraction into HCl. The results for standard rock sample, AGV-1, showed a good agreement with those obtained by US Geological Survey as well as reported values in other articles.

• Journal of the Korean Chemical Society
• /
• v.45 no.1
• /
• pp.25-30
• /
• 2001

A selective kinetic fluorimetric method for the determination of trace rhodium(Ⅲ), based on the catalytic effect of rhodium(Ⅲ) on the oxidation of nile blue by periodate have been studied. The effects of pH and concentrations of nile blue, sodium periodate, trioctyl phosphine oxide(TOPO) and temperature were investigated. The calibration curve for rhodium(Ⅲ) ion was linear over the range from 100 ng/mL to 0.1 ng/mL and the detection limit was 0.01 ng/mL under the optimal experimental conditions. Effects of interferences from several cations and anions for the determination of rhodium(Ⅲ) were also investigated.

• Journal of the Korean Chemical Society
• /
• v.7 no.4
• /
• pp.271-276
• /
• 1963

The distribution ratio of lanthanon nitrates in the TBPO- and TOPO-toluene systems were studied radiometrically as a function of solvent, nitrate and atomic number(Z). The plots of log Kd vs. Z shows two straight lines which are crossing at Z = 63∼64. The solvent dependency was same for lighter and heavier lanthanons but nitrate dependency was different between the two parts.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.7
• /
• pp.2391-2396
• /
• 2011

Benzonaphthofurandiones containing four coplanar fused aromatic rings were synthesized and evaluated for their cytotoxicity against five human cancer cell lines, and their inhibitory activity on topoisomerases. These benzonaphthofurandiones were prepared by condensation of 2,3-dichloronaphthoquinone and three aromatic diols with base catalysts in alcohol. The synthesized compounds were o-alkylated with six dialkylaminoalkyl halides. The hydroxy derivatives (8a-8g) exhibited relatively potent cytotoxicity among the prepared compounds. These compounds were evaluated as excellent inhibitors against topoisomerase II (topo II). Especially, the hydroxy analogue with branched methyl side chain (8e) showed high cytotoxicity against cancer cell lines and good inhibitory activity on topo II.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.359-362
• /
• 2005

알파전용 액체섬광기를 이용하여 지하수내 Polonium을 간편하고 신속하게 측정하는 방법을 연구하였다. 추출섬광용액으로 HDEHP, TNOA, TOPO 또는 NDA 등을 사용하지만 본 실험에서는 POREX(77g TOPO, 180g Naphthalene, 4.0g PBBO/1L Toluene)를 사용하였다. 지하수의 액상을 $1M\;H_2SO_4-0.01M\;NaCl$로 맞추어주고 0.012M POREX를 추출액으로 사용하여, 분리 추출하므로써 실험의 추출효율 및 재현성을 조사하였다. 위 조건에서의 Polonium 분배계수는 $10^4$ 이상으로 알려져 있다. 표준물질인 Po-209(NIST SRM 4326)를 Po의 측정효율 및 추출효율을 조사하는데 이용하였다. 실제 지하수에 위 실험방법을 적용하여 지하수의 Polonium을 측정하였다.

• Korean Journal of Plant Taxonomy
• /
• v.49 no.4
• /
• pp.282-293
• /
• 2019

Broussonetia × kazinoki Siebold has long been utilized as a major component in the manufacturing of Korean traditional paper, hanji, and has been suggested as a hybrid species of B. papyrifera and B. monoica. By applying three molecular markers, chloroplast (cp) ndhF-rpl32 IGS, a nuclear ribosomal internal transcribed spacer, and the TOPO6 gene, the hybrid origin of B. × kazinoki is tested. As a result, B. × kazinoki in Korea is demonstrated to be a hybrid of B. monoica × B. papyrifera, most likely formed naturally in Korea. The cp haplotypes detected provided information about the origins and genetic diversity of the maternal lineage B. monoica and paternal lineage B. papyrifera. The two nuclear markers were supplemented to each other, leading to the discovery of introgression in Broussonetia.