중추에 의한 가토 신장기능조절에 미치는 Forskolin의 영향

고정태,김경근,국영종 전남대학교 치과대학 1993 전남치대논문집 Vol.5 No.1

Various endogenous neurotransmitter systems have been shown to take part in central regulation of renal function through the medium of intracellular cAMP, a second messenger of cellular events in response to activation of membrane receptors. This study was undertaken to observe further the influence of adenylate cyclase activation, leading to increased cAMP levels, on the central regulation of renal function. Forskolin, an activator of adenylate cyclase, was administered into a lateral ventricle (icv) of rabbit brain in doses ranging from 13 to 130 ㎍/㎏ and changes in renal function were observed. With 13 ㎍/㎏ icv no marked changes in renal function were noted. Tripling the does to 40 ㎍/㎏ icv produced marked increases in urine flow rate and excretory rate of Na and K along with increased renal perfusion (=C_(Na)) and the fraction of sodium excreted (=FE_(Na)). Increasing the does further up to 130 ㎍/㎏ icv elicited marked diuresis, natriuresis and kaliuresis for about 20 min, with increased renal hemodynamics. The fraction of filtered sodium excreted (=FE_(Na)), indicative of the degree of inhibition of tubular sodium reabsorption, also increased. No significant changes in systemic pressure were noted. DMSO, the solvent employed to dissolve forskoin, given icv in 0.15㎖ up to the concentration of 63%, did not produce significant diuresis, natriuresis, kaliuresis, nor any significant changes in systemic blood pressure. Therefore, forskolin was dissolved in 63% DMSO. When given intravenously, however, forskolin 130 ㎍/㎏, a dose which elicits marked diuresis and natriuresis when given icv, did not produce diuretic effect, but rather tended to decrease urinary output and sodium excretion, implicating central mechanism of the icv effect. In preparations in which one kidney was denervated, with the other serving as control, the denervated kidney responded to icv forskolin with more prominent diuresis and natriuresis, suggesting humoral mediation of the effect. Plasma levels of ANP significantly increased, up to more than double the control level at 20 min after 130 ㎍/㎏ forskolin icv, when the natriuresis reached the peak. These observations suggest that endogenously produced cAMP, by activating adenylate cyclase cause the renal effects, mediated by ANP, and indicate that the adenylate cyclase-cAMP system in involved in central regulation of renal function.

Diazepam의 중추성 신장기능조절과 그 작용기전에 관하여

고정태,김경근 전남대학교 치과대학 1995 전남치대논문집 Vol.7 No.1

The renal function is under regulatory influence of central nervous system, in which various neurotransmitter and neuromodulator systems take part, and it is known that diazepam have antianxiety and anticonvulsant effects through the benzodiazepine site coupled GABA receptor-CI- ion channel complex. This study was, therefore, undertaken to delineate the renal effects of diazepam and its mechanism in the regulation of renal function. Diazepam given into a lateral ventricle (icv) of rabbit brain in does ranging from 10 to 100㎍/㎏ icv elicited increases, in roughly dose dependent manner, in Na excretion, renal plasma flow (RPF), glomerular filtration rate(GFR), fraction of filtered sodium excreted(FE_NA) and K excretion, as well as in urine flow rate. NO significant changes in systemic blood pressure were shown. The vehicle alone did not produce any effect. When the same dose were given intravenously, all the parameters of renal function and systemic blood pressure did not show any changes, indicating that the icv effects were indeed of the central origin. The experiments in which renal nerve activity was monitored showed that diazepam, 100㎍/㎏ icv, transiently elicited decrease in the activity, and then recovered after 5 min. In experiments in which the plasma levels of atrial natriuretic peptides(ANP) were measured, plasma ANP level increased about 7 times over the control level after 100㎍/㎏ icv, the peak coinciding with natriuresis and diuresis. Muscimol, a specific agonist of GABA receptor, produced no significant changes in the does of 0.1 to 0.3㎍/㎏, but elicited antidiuresis and antinatriuresis, in 1.0㎍/㎏ related to decreases in systemic blood pressure. When muscimol 0.3㎍/㎏ icv. a dose minimally affecting the renal function, was given 3 min prior to 30㎍/㎏ diazepam icv, the renal effects of the latter tended to decreases in urine flow rate and Na excretion with decrease in systemic blood pressure. It is indicated that renal effect of icv diazepam is not mediated to GABAergic system. β-CCM, a benzodiazepine inverse agonist, 10~100㎍/㎏ icv, tended to diuresis and natriuresis without hemodynamic changes. When 100㎍/㎏ diazepam icv was given 3 min after β-CCM, urine flow rate and Na excretion of diazepam 100㎍/㎏ was not affected. These may be resultant to inhibition of diazepam binding to tis receptor by the icv β-CCM and the renal effects of β-CCM itself. These results suggested that diazepam may participate in the central regulation of renal function, bringing about natriuresis and diuresis which are related to increased plasma ANP levels and partly decreased renal nerve activity, and that the effect many not be mediated to activation of GABAergic system.

Symposium : BMP, myth or fact (reality)

고정태 대한치주과학회 2009 대한치주과학회 학술대회자료집 Vol.2009 No.2

초고주 원편파를 이용한 회전 플라즈마 무전극 황전등 방전

고정태(Jung Tae Ko),원동호(Dong Ho Won),김진중(Jin Joong Kim),김정원(Jeong Won Kim) 대한전기학회 2003 대한전기학회 학술대회 논문집 Vol.2003 No.7

고주파방전 무전극 형광등(직관 및 환형) 광원 성능향상을 위한 신기술

김진중,고정태,원동호,백홍구,박해일,이태일 한국조명전기설비학회 2003 조명.전기설비 Vol.17 No.1

Epressions of Angiogenic and Angiostatic Genes in Cyclosporin A-induced Gingival Overgrowth

Park, Young-Seob,Koh, Jeong-Tae,Kim, Kyung-Keun 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.1

Cyclosporine A (CyA)는 장기 이식 및 자가면역 질환의 치료제로 널리 사용되는 면역억제제로서, 신독성, 간독성, 구강 내 치은비대증 등의 부작용을 초래한다. 치은 조직 내 섬유아세포, 세포외 기질, 혈관조직의 증가를 동반한 치은비대증의 기전으로는 콜라젠 섬유의 생성 증가와 파괴 감소 등이 제시되고 있으나 명확하게 규명되고 있지는 않다. 특히, 치은 증식에서의 혈관조직 변화와 관련하여 혈관 생성 인자의 관여와 그 역할에 대해서는 알려진 바 없다. 본 연구에서는 CyA를 흰쥐에 피하 주사하여 치은 비대증을 유발한 후, 치은 조직에서 혈관생성 촉진인자 [angiopoietin1(AGP1), basic fibroblast growth factor(bFGF), vascular endothelial growth factor(VEGF)]와 혈관생성 억제인자 [angiopoietin2(AGP2), brain-specific angiogenesis inhibitors (BAIs), thrombospondin 2 (TSP2)]의 발현정도를 역전사 중합 반응법(RT-PCR)으로 비교함으로 치은 비대증 발생과 혈관생성과의 관계를 알아보고자 하였다. 또한, CyA에 의한 혈관생성인자의 발현 변화가 치은 비대증의 주 작용세포로 알려진 치은 섬유아세포에서 초래되는지를 알아보고자 일차 배양한 치은 섬유아세포에서의 혈관생성 관련 유전자들의 발현을 역전사 중합 반응법과 Western blot분석을 통하여 비교 관찰하였다. CyA 10 mg/kg를 6주간 투여한 흰쥐의 치은 조직으로부터 RT-PCR을 시행한 결과, AGP1, bFGF, VEGF, AGP2, BAI1의 mRNA 발현은 정상 흰쥐에 비해 뚜렷한 변화를 보이지 않았으나, TSP2 발현은 현저히 감소되었다. 치은 조직에서의 TSP2발현 정도는 5, 10, 15 mg/kg의 CyA에 의해 용량 의존적으로 감소하였으며, 10 mg/kg를 투여한 3주, 6주, 12주의 치은조직에서도 모두 감소하였다. 흰쥐의 치은조직으로부터 일차 배양한 치은 섬유아세포에 치은 비대증을 유발하는 CyA 혈중 농도로 알려진 1000 ng/ml을 투여한 후에는, VEGF, AFP1, bFGF, AgP2, BAI1, BAI2의 mRNA발현이 정상 섬유아세포에 비해 뚜렷한 변화를 보이지 않았으나, TSP2 mRNA 발현은 현저히 감소하였다. 정상 인간의 치은 조직으로부터 배양한 치은 섬유아세포에서도 TSP2 mRNA 발현은 CyA의 투여 용량 (250, 500, 750, 1000 ng/ml)과 시간(1, 2, 3, 4일)에 따라 감소하였으며, 배양한 치은 섬유아세포에서 TSP 단백 발현도 투여한 CyA의 농도 (250∼1000 ng/ml)에 의존적으로 감소하였다. 이상의 결과로 CyA 투여에 의해 혈관증식과 함께 초래되는 치은 비대증에서 혈관생성 촉진인자의 변동은 관찰할 수 없는 반면 혈관생성 억제인자인 TSP2 발현은 억제되며, 이러한 작용은 치은 섬유아세포에서도 나타남을 알 수 있었다. 이는 치은 비대증의 병인 중에 하나인 혈관증식에는 혈관생성 촉진인자보다는 혈관생성 억제인자가 주로 관여하고 있음을 시사한다.

Morphological Property and In vitro Enzymatic Degradation of Modified Chitosan as a Scaffold

배인호,고정태,장원구,임현필,박상원,이광민,박영준,박인규,정명호 한국고분자학회 2011 Macromolecular Research Vol.19 No.12

Chitosan (CS) was proposed as a promising candidate scaffold for tissue engineering. However, some drawbacks of natural CS remain. The current study modified CS by conjugating thiol to CS polymer (Thio-CS) and substantiated its three-dimensional microstructure and physical properties such as swelling or degradation. The Thio-CS was obtained by CS modification using 2-iminothiolane-HCl (2-IT). Because of the formation of disulfide bonds between thiol moieties based on oxidation of the immobilized thiol groups of CS, Thio-CS exhibits in situ gelling properties according to the reducing amount of free thiol. The content of the thiol group was increased as the amount of 2-IT increased. The swelling test demonstrated that Thio-CS can absorb up to 3.5 times its weight of phosphate buffered saline within 1 h and that the pore size and amount significantly increased with incubation time. The Thio-CS enzymatic degradation rate according to velocity was investigated. The results showed that Thio-CS was more resistant to lysozyme as viscosity increased. Thio-CS sponges were fabricated using freezedrying. The lyophilized Thio-CS had a homogeneous honeycomb-like shape, and its pores were relatively smaller (<2 μm) than those of unmodified CS (>2 μm). These results suggest that Thio-CS might be a candidate regenerative therapeutic device.

고주파 방전 무전극 형광등 광원 기술 : 직관 및 환형

김진중,고정태,원동호 한국조명·전기설비학회 2002 한국조명·전기설비학회 학술대회논문집 Vol.2002 No.-

This paper describes the first-year accomplishments in the R&D project entitled, “Electrodeless Fluorescent Lamp Technology Using High-Frequency Discharges (Linear and Circular Type),” supported by a contact from the Korea Energy Management Corporation (KEMCO). One of the most important accomplishments in the project is that the luminance of electrodeless fluorescent lamps is increased more than 25% when the hybrid technique of capacitive and inductive couplings is utilized for both linear and circular types of high-frequency discharge fluorescent lamps compared to the case where pure capacitive couplings are used. We present the results of the experiments and the status of the development efforts in the project.

Cytotoxicity and physical properties of tricalcium silicate-based endodontic materials

장영은,이빈나,고정태,박영준,주남억,장훈상,황인남,오원만,황윤찬 대한치과보존학회 2014 Restorative Dentistry & Endodontics Vol.39 No.2

Objectives: The aim of this study was to evaluate the cytotoxicity, setting time and compressive strength of MTA and two novel tricalcium silicate-based endodontic materials, Bioaggregate (BA) and Biodentine (BD). Materials and Methods: Cytotoxicity was evaluated by using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5- ((phenylamino)carbonyl)-2H-tetrazolium hydroxide (XTT) assay. Measurements of 9 heavy metals (arsenic, cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc) were performed by inductively coupled plasma-mass spectrometry (ICP-MS) of leachates obtained by soaking the materials in distilled water. Setting time and compressive strength tests were performed following ISO requirements. Results: BA had comparable cell viability to MTA, whereas the cell viability of BD was significantly lower than that of MTA. The ICP-MS analysis revealed that BD released significantly higher amount of 5 heavy metals (arsenic, copper, iron, manganese, and zinc) than MTA and BA. The setting time of BD was significantly shorter than that of MTA and BA, and the compressive strength of BA was significantly lower than that of MTA and BD. Conclusions: BA and BD were biocompatible, and they did not show any cytotoxic effects on human periodontal ligament fibroblasts. BA showed comparable cytotoxicity to MTA but inferior physical properties. BD had somewhat higher cytotoxicity but superior physical properties than MTA.

치근 천공 치료 재료의 생체친화성의 비교

강민경,배인호,고정태,황윤찬,황인남,오원만 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.3

This study was carried out in order to determine in vitro biocompatibility of white mineral trioxide aggregate (MTA), and to compare it with that of the commonly used materials, i. e. calcium hydroxide liner(Dycal), glass ionomer cement (GIC), and Portland cement which has a similar composition of MTA. To assess the biocompatibility of each material, cytotoxicity was examined using MG-63 cells. The degree of cytotoxicity was evaluated by scanning electron microscopy (SEM) and a colorimetric method, based on reduction of the tetrazolium salt 2,3 bis {2methoxy 4nitro 5〔(sulfenylamino) carbonyl〕2H tetrazolium hydroxide} (XTT) assay. The results of SEM revealed the cells in contact with GIC, MTA, and Portland cement at 1 and 3 days were apparently healthy. In contrast, cells in the presence of Dycal appeared rounded and detached. In XTT assay, the cellular activities of the cells incubated with all the test materials except Dycal were similar, which corresponded with the SEM observation. The present study supports the view that MTA is a very biocompatible root perforation repair material. It also suggests that cellular response of Portland cement and GIC are very similar to that of MTA. 이번 연구는 치근 천공의 치료 재료인 white mineral trioxide aggregate (MTA)를 흔히 사용되는 calcium hydroxideliner(Dycal^(R), glass ionomer cement (GIC), 그리고 MTA와 유사한 성분을 가진 Portland cement와 세포독성 실험으로 생체 친화성을 평가하는 것이다. 세포독성의 정도는 MG-63 세포를 이용해 주사전자 현미경적 관찰과 수용성 tetrazolium salt를 이용한 흡광도를 측정 (XTT assay)하여 평가하였다. SEM 관찰에서, 1일과 3일째 모두에서 GIC와 MTA, Portland cement표면에서는 잘 부착된 세포를 보여주었다. 반면에, Dycal 표면의 세포들은 둥글고 부착되지 않은 양상을 보여주었다. XTT assay에서는 Dycal을 제외한 모든 재료에서 유사하게 높은 세포 활성도를 보여주었으며, 이는 SEM 관찰 소견과 일치하였다. 이번 연구는 MTA가 생체친화적인 재료라는 견해를 뒷받침한다. 또한 Portland cement와 GIC에서도 MTA와 유사한 세포반응을 보여주었다.