Hyperthermia-induced Apoptosis is Independent upon DNA Strand Breaks in Human Lymphoid Cells

정화진,가원혜,황지나,서영록 대한약리학회 2004 The Korean Journal of Physiology & Pharmacology Vol.8 No.6

Heat shock (43oC for 60 minutes) is sufficient to induce apoptosis in a wide number of cell lines. In this study, we asked whether DNA strand breaks are responsible for this phenomenon. Using the highly sensitive comet assay for DNA damage detection, we were unable to demonstrate DNA breaks immediately after heat shock in Raji human lymphoid cells. It showed that DNA breaks were not necessary for hyperthermic apoptosis, since its activity is indicative of DNA lesions. Here, we present a suggestion that a protein(s) is the major target for heat shock apoptosis. We firstly found glycerol, which reportedly stabilizes protein structure, showed a protective effect in Raji cells against hyperthermic apoptosis. In addition, quercetin, which modulates transcription of the heat shock protein family members, enhanced apoptotic death induced by hyperthermia. Furthermore, Raji cells are protected by a pre-mild heat treatment prior to the killing dose of heat shock.

유연한 연결기를 갖는 새로운 방향족 Polyformamidine의 합성과 성질

정화진 한국섬유공학회 2003 한국섬유공학회지 Vol.40 No.5

New aromatic polyformamidines were prepared by reaction of triethyl orthoformate with aromatic diamines containing various flexible linkages such as ether, isopropylidene, and hexafluoroisopropylidene between aromatic rings in N.N-dimethylsufoxide(DMSO) via high temperature solution polycondensation. The proposed structures of the resultant polymers were confirmed by elemental analysis, IR- and $^1$H-NMR spectroscopy. These polymers had inherent viscosities up to 0.42 dL/g, and most of them could be readily soluble in aprotic amide solvents including N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, and DMSO at room temperature. Wide angle X-ray diffractograms(WAXD) revealed that the polymers were partially crystalline or amorphous. The glass transition temperatures of the polymers could be determined by differential scanning calorimetry (DSC) and were in the range of 118∼245 $^{\circ}C$. Thermogravimetric analysis(TGA) indicated that the polymers are stable in nitrogen up to 300 $^{\circ}C$, and 10% weight loss occurred in the temperature range of 320∼395 $^{\circ}C$ in air.

두리번거리다

정화진 새얼문화재단 2015 황해문화 Vol.88 No.-

Pendant Phenyl 구조를 함유하는 가용성 복소오원환계 Polyazomethine의 합성과 성질

정화진 한국섬유공학회 1999 한국섬유공학회지 Vol.36 No.2

New aromatic polyazomethines were synthesized from two tetraphenylated heterocyclic diamines, 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole (DATPP), and 3,4-bis(4-aminophenyl)-2,5-diphenylthiophene (DATPT) with two aromatic dialdehydes, isophthalaldehyde (IPA), and terephthalaldehyde (TPA) by solution polycondensation in o-chlorophenol at room temperature. In addition, DATPP-based copolyazomethines were prepared by reacting the diamine with a combination of IPA and TPA. These polymers had inherent viscosities in the range of 0.32~0.62 dL/g and showed amorphous patterns in X-ray diffraction studies. The polyazomethines derived from IPA and the copolyazomethines with TPA containing less than 50 mol% were fairly soluble in various organic solvents such as N-methyl-2-pyrrolidone, o-chlorophenol, and 1,1,2,2-tetrachloroethane. In thermogravimetric analysis (TGA), all the polymers did not lose weight below 41$0^{\circ}C$ in air and nitrogen, and their 5% weight loss temperature in air and nitrogen were in the range of 445~485$^{\circ}C$ and 490~52$0^{\circ}C$, respectively. Differential scanning calorimetry curves also revealed decomposition behaviors similar to those observed in TGA analysis with no transition below the decomposition temperatures.

항종양 인자 p53 및 PTEN의 활성화를 중심으로 하는 항산화제 셀레늄의 암 예방 기전 연구

정화진,서영록 대한암예방학회 2007 Journal of cancer prevention Vol.12 No.4

Selenomethionine (SeMet) has been identified as one of the organic selenium compounds although the mechanism of chemopreventive action of SeMet was not clear yet. In our previous study, we suggested that p53 might be involved in chmopreventive effect of SeMet. Here, we investigated the implication of the p53 modulated by redox signal in response to SeMet in cancer prevention. We confirmed that the p53 accumulation was significantly increased in response to SeMet as dose-dependent manner. In addition, the differential localization of p53 protein was observed in nucleolus contrast with in redox factor 1 (Ref-1)-dominant negative cells indicating that p53 function for genomic stability might be modulated by redox signaling. On the other hand, PTEN known as a tumor suppressor with the inhibition of PI3K/Akt signaling pathway has no significant differences in the presence with SeMet suggesting that the chemopreventive mechanism of SeMet might be on PTEN-independent pathway. In our study, we suggested that p53 activation and localization in nucleolus might be a distinct cellular pathway of SeMet as one of the chemopreventive compounds. (Cancer Prev Res 12, 256-260, 2007) Key Words: p53, PTEN, Selenomethionine

한국 실학사상 : 실학자들의 사상과 교육관

정화진 이화여자대학교 사범대학 교육학과 1973 교육 연구 Vol.- No.41

Negative feedback regulation of Wnt signaling by Gβγ-mediated reduction of Dishevelled

정화진,Hyun Joon Kim,Suk Kyung Lee,Rokki Kim,Will Kopachik,Jin-Kwan Han,조익훈 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.10

Wnt signaling is known to be important for diverse embryonic and post-natal cellular events and be regulated by the proteins Dishevelled and Axin. Although Dishevelled is activated by Wnt and involved in signal transduction, it is not clear how Dishevelled-mediated signaling is turned off. We report that guanine nucleotide binding protein beta 2 (Gnb2; Gβ2) bound to Axin and Gβ2 inhibited Wnt mediated reporter activity. The inhibition involved reduction of the level of Dishevelled, and the Gβ2γ2 mediated reduction of Dishevelled was countered by increased expression of Axin. Consistent with these effects in HEK293T cells, injection of Gβ2γ2 into Xenopus embryos inhibited the formation of secondary axes induced either by XWnt8 or Dishevelled, but not by β-catenin. The DEP domain of Dishevelled is necessary for both interaction with Gβ2γ2 and subsequent degradation of Dishevelled via the lysosomal pathway. Signaling induced by Gβ2γ2 is required because a mutant of Gβ2, Gβ2 (W332A) with lower signaling activity, had reduced ability to downregulate the level of Dishevelled. Activation of Wnt signaling by either of two methods, increased Frizzled signaling or transient transfection of Wnt, also led to increased degradation of Dishevelled and the induced Dishevelled loss is dependent on Gβ1 and Gβ2. Other studies with agents that interfere with PLC action and calcium signaling suggested that loss of Dishevelled is mediated through the following pathway: Wnt/Frizzled →Gβγ → PLC →Ca+2/PKC signaling. Together the evidence suggests a novel negative feedback mechanism in which Gβ2γ2 inhibits Wnt signaling by degradation of Dishevelled.

분자생물학적 방법에 의한 세포 독성 측정

정화진,김동욱,Chung Hwa-Jin,Kim Dong-Wook 한국작물학회 2004 Korean journal of crop science Vol.49 No.suppl1

정전류 쵸핑을 이용한 구형파 구동형 고압 수은 방전등용 전자안정기 설계에 관한 연구

정화진,지철근 한국조명전기설비학회 1995 조명.전기설비 Vol.9 No.1

본 논문에서는 고압방전등 전자안정기의 제작시 발생하는 음향공진 현상을 방지하기 위해서 방전등에 55.5[Hz]구형파를 인가하였고, 이 경우 방전등의 부저항특성 및 방전등의 시동특성에 효과적으로 대응하기 위해 인버터에 공급되는 전원을 정전류 쵸핑에 의한 DC전압으로 하였다. 설계된 전자안정기는 220[V]AC전원 전압을 정류하고, 스위칭 주파수가 30[kHz]인 정전류 쵸핑으로 방전등의 관전압에 맞는 DC전압을 인버터에 공급하며, 인버터에서 55.5[Hz]의 구형파를 방전등에 인가하도록 설계하였다. 설계한 전자안정기를 제작하여 실험한 결과, 비교된 재래식 안정기보다 효율이 향상되고, 플리커현상이 발생하지 않으며, 방전등 시스템의 정전력화 및 조광기능을 갖추고 있어서 탁월한 실용성을 입증하였다. 제작한 전자안정기의 용량은 300[W] 입력전압은 220[V]이며, 실험에 사용한 램프는 정격전력이 300[W]이며 관전압 135[V] 관전류는 2.0[A]로서 측정하였다. There are many articles about the HID lamps about it's characteristics and simulation methods for lamp design or ballast design. For the electronic ballasts of HID lamps, There are some problems caused by acoustic-resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods suggested are high frequence driving over 100[kHz], and mixed frequence driving which alternates high frequence and low frequence, and squarewave driving etc. This study suggests the electronic ballast of HID lamps that solves the problems of acoustic-resonance, and can control the luminance by constant current boostes chopper of which frequence is 30[kHz] and by the squarewave driving of which frequence is 55.5[Hz.] As follows, we have the good electronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

디젤발전기실 화재진압용 미분무 소화설비의 화재실증실험 연구

정화진,곽지현,김영한,박문희,정준호 한국화재소방학회 2014 한국화재소방학회 학술대회 논문집 Vol.2014 No.춘계