S-1. Mechanism of AFB1 Hepatocarcinogenesis and Its Prevention by Butylated Hydroxyanisole

지은정 한국균학회 1985 韓國菌學會誌 Vol.13 No.4

Microsome mediated aflatoxin B₁ (AFB₁) binding to exogenous and endogenous DNA and its modulation by cytosolic GSH S-transferases have been examined in rat and hamster livers. Kinetic studies indicated that cytosol from hamster is several-fold more effective than that from the rat in inhibiting AFB₁ binding to DNA. Low concentration of GSH (0.1∼0.2 mM) are required for 50% inhibition of AFB₁-DNA binding by cytosol. In contrast to the results of exogenous DNA, AFB₁-DNA binding with combined microsome-cytosol fractions is less from the hamster than those from the rat. Cytosol inhibition of AFB₁-DNA binding is almost completely reversed in the presence of 1 mM levels of either trichloropropene oxide or styrene oxide. Quantitation of AFB₁-DNA binding and AFB₁-GSH conjugation indicate an inverse relationship between these two processes. Cytosol from the rat has less capacity than that from the hamster to form an AFB₁-GSH conjugate. Hepatic GSH levels are about equal (6∼7 mM) in both species. I.P. administration of 14C AFB₁ 2 h before sacrifice gives more AFB₁ binding to hepatic nuclear DNA in rats than in hamsters. However, depletion of hepatic levels by 80% by the administration of diethylmaleate increases AFB₁-DNA binding 2-3 fold in both species. The role of cytosolic GSH S-transferases in controling carcinogenesis is discussed. Butylated hyroxyanisole pre-treatment of male rats has been examined for its effect on in vivo and in vitro hepatic aflatoxin B₁-DNA binding in these animals. No difference either in cytochrome P-450 content or microsome mediated AFB₁-DNA was observed between livers from control and treated rats. However, cytosols from treated animals showed severalfold more inhibition of microsome mediated AFB₁ binding to either exogenous and endogenous DNA than cytosols from controls. Presence of 1 mM level of either trichloropropene oxide or styrene oxide partially reversed the cytosolic inhibition of AFB₁-DNA binding. Intraperitoneal administration of AFB₁ 2 hour before sacrifice produced 50% less AFB₁ binding to nuclear DNA in BHA treated than in control animals. The role of GSH S-transferases in treated rate in the modulation of AFB₁-DNA binding is considered.

사람 소장 Ornithine Aminotransferase 의 성상

지은정,노혜원,양병철,조옥현,김형로 의과학연구소 1989 全北醫大論文集 Vol.13 No.1

Some properties of ornithine aminotransferase, which transfers the amino group of ornithine to α-ketoglutarate in human intestine were characterized. The results of this study were as follows. 1.Ornithine aminotransferase showing optimal pH 8.5 was mainly localized in cytosol and its Km for L-ornithine and α-ketoglutarate was 2.0 mM and 2.7 mM respectively. The enzyme exhibited the absolute requirement of pyridoxal phosphate for its activity. 2.By storage at 4℃for 5 day, 75% of the enzyme activity was lost and on heat treatment at 60℃ for 5 min, 80% of that was inactivated but the stability was markedly increased to almost 100% by the addition of 0.05mM pyridoxal phosphate to the enzyme solution. 3. From the fact that the enzyme activity is completely inhibited by the presence of p-chloromercuribenzoate or HgCl_2, it can be strongly suggested that sulfhydryl group is involved in the catalytic site of ornithine aminotransferase.

家兎肝의 Adenosine Diphosphate Ribose Pyrophosphohydrolase 同位 酵素에 關한 硏究

池垠政 전북대학교 의과학연구소 1980 全北醫大論文集 Vol.4 No.1

Mg^2+-dependent and -independent adenosine diphosphate ribose pyrophosphohydrolase(ADPRase), both of which catalyze the hydrolysis of ADP-ribose to AMP and ribose-5'-phosphate were separated each other by ammonium sulfate fractionation and their enzymatic properties were characterized. These two isoenzymes of ADPRase were not only tissue-specific but also subcellular organelle-specific in their distribution, Mg^2+-independent form being located in nuclei and mitochondria while Mg^2+-dependent form occurring only in the cytoplasm of rabbit liver. The enzymatic properties of cytoplasmic Mg^2+-independent ADPRase converted from Mg^2+-dependent form were identical to those of the nuclear Mg^2+-independent form in Km value, inhibition by adenine nucleotides, optimal pH, and heat stability, suggesting that nuclear Mg^2+-independent ADPRase originate from the cytoplasmic Mg^2+-dependent ADPRase. However, the nuclear and cytoplasmic Mg^2+-independent ADPRases from the liver showed different enzymatic characteristics in their Km value and adenine nucleotide inhibition from those of other tissues such as kidney, indicating that liver Mg^2+-independent ADPRase is another distinct isoenzyme, even though all of them require Mg^2+ for their activity. The labile Mg^2+-dependent ADPRase from the liver was easily inactivated during the course of storage and purification but the loss of activity was completely prevented in the presence of 35% glycerol in the enzyme solution.

Inhibition of Aflatoxin Indrced Hepatocarcinogenesis by Antioxidant, BHA

지은정 啓明大學校 醫科大學 1989 계명의대학술지 Vol.8 No.2

Aflatoxin which is widely distributed in the human food supply is extremely potent animal toxins and is welknown hepatocarcinogen. Primary liver cancer is not prevalent form of cancer in western countries, however, there are certain geographical area where the incidence is significantly elavated, namely southeast Asia, China, southeastern India and subsaharan Africa, where temperature and humidity would favor contramination of human food stufls.

赤血球의 Methylene Blue攝取 와 Pentose 形成能에 미치는 高溫保管의 影響

池垠政 全北大學校 1975 論文集 Vol.17 No.-

Human erythrocytes were incubated at 30°for various time intervals up to 7 days in Na-phosphate buffer(pH 7.4) or acid-citrate-dextrose(ACD) solution. During incubation, the uptake of methylene blue and the formation of pentose from glucose or inosine were assayed to observe the effect of storage at high temperature(30°) on the glucose metabolism of erythrocytes. During incubation of red cells at 30°in Na-phosphate buffer, the methylene blue uptake in the presence of glucose decreased rapidly, and the formation of pentose from glucose also decreased gradually. The concentration of pentose in the erythrocytes was not correlated to the activity in converting pentose to glucose-6-phosphate. In contrast when inosine was added in place of glucose to red cell suspension, the methylene blue uptake and pentose formation remained unchanged during the incubation, and also the activity of converting pentose to glucose-6-phosphate was well correlated to the pentose concentration in the cells. The erythrocytes incubated at 30°in ACD solution showed the similar changes in methylene blue uptake, penotse formation in the presence of glucose, and the converting activity of pentose to glucose-6-phosphate, however, when inosine was substrate, methylene blue uptake, pentose formation, and the converting activity of pentose to glucose-6-phosphate decreased gradually during incubation. These results suggest that the incubation of erythrocytes at 30°causes the rapid depletion of adenosine triphosphate(ATP) in the erythrocytes, leading to the decreased activity in nucleoside phosphorylase and in the conversion of triose phosphate to glucose-6-phosphate in Embden-Meyerhof Pathway. It is also suggested that the activity in the formation of triose phosphate from pentose in pentose phosphate pathway and in the later half of Embden-Meyerhof Pathway (triose phosphate→lactate) is relatively well preserved during the incubation of red cells at 30°up to 7 days.

세대 간 일자리 대체관계 및 상생을 위한 정책방향

지은정,오학수,정미경,손동기 한국고용정보원 2021 연구사업보고서 Vol.- No.-

미국 고령자 직업훈련의 고용성과가 노인일자리사업에 주는 함의

지은정 한국사회학회 2014 한국사회학회 사회학대회 논문집 Vol.2014 No.6

[내 인생의 멋진 만남] 일하는 신부님

지은정 샘터사 1998 월간 샘터 Vol.29 No.5

[정책제안] 지자체에서 양질의 노인일자리 확대하려면

지은정 한국자치학회 2019 월간 공공정책 Vol.160 No.-

통합적·체계적 노인 사회활동 만들어야

지은정 한국자치학회 2019 월간 공공정책 Vol.163 No.-