Effects of Iron Chelators and Reducing Agents on Iron induced Lipid Peroxidation

Park, Chan-Hyun,Lee, Chung-Soo,Shin, Yong-Kyu,Lee, Kwnag-Soo 중앙대학교 의과대학 의과학연구소 1987 中央醫大誌 Vol.12 No.3

금속이온 가운데 iron은 산소라디칼에 의한 생체 세포내 거대분자의 파괴를 촉매하며 iron의 환원이 지질의 과산화에 주요한 역할을 하는 것으로 알려져 있다. OH·을 생성하는 Haber-Weiss reaction은 iron에 의하여 촉진되며, 생성된 OH·이 지질의 과산화를 초래하는 물질로서 시사되고 있다. Iron에 의한 불포화 지방산의 과산화에는 ferrous-dioxygen복합체 또는 제일 철(혹은 착화 제일 철)의 자가산화 반응중에 산소라디칼이 형성되어 이들이 관여하는것으로 추측하고 있다. 한편 다수의 보고들은 생체내에 존재하는 환원제의 하나로써 ascorbate가 지질의 과산화를 포함한 세포내 거대분자의 손상을 초래하며 또한 금속이온의 독성작용을 항진시킨다고 보고하고 있다. 이와 같이 iron의 산화와 환원이 지질의 과산화에 관여할 가능성에서 볼 때, ascor-bate와 같은 환원제들의 환원력이 갖는 역할은 이들의 독성작용에 기여하는 작용을 밝히는 계기가 될 것이다. 그러므로 본 연구에서는 iron의 산화 또는 환원에 따른 조직 손상의 정도를 여러 환원제와 iron chelator존재하에서 나타나는 현상으로써 측정하였다. 이들 효과는 iron의 산화중에 유리되는 산소라디칼과 microsome의 지질의 과산화를 통하여 관찰하였다. 또한 이온의 산화 및 환원에 미치는 iron chelator와 환원제들의 영향을 관찰하였으며 더 나아가 iron의 산화 및 환원과 이에 따른 지질의 과산화 사이의 관계를 규명하였다. Fe^++은 microsome의 질을 과산화시켰으나 Fe^++은 100uM농도까지 지질의 과산화에 약간의 영향을 나타내었다. 중성의 반응액에서 Fe^++ 은 5분내에 거의 완전히 산화되었으며 이와 동시에 ferricytochrom c가 환원되었다. 이에 반하여 Fe^++은 ferricytochrom c의 환원에 거의 영향을 나타내지 아니 하였다. Fe^++에 의한 microsome지질의 과산화는 O_2의 scavenger인 SOD와 H_2o_2의 scavenger인 catalase 에 의하여 억제되었다. EDTA 또는 DETAPAC은 Fe^++에 의한 microsome 지질의 과산화에 이중효과를 나타내었으며 EDTA 또는 DETAPAC과 iron의 결합이 1:2일때 iron에 의한 지질의 과산화는 증가하였으나, 이러한 비율에서 벗어날 때는 오히려 iron에 의한 지질의 과산화는 억제되었다. ADP 는 Fe^++에 의한 지질의 과산화를 억제하였으나 Fe^++에 의한 지질의 과산화를 촉진시켰다. EDTA또는 ADP 는 Fe^++의 자발적인 산화를 촉진하였으나 DETAPAC은 용량에 따라 억제하였다. 한편 salicylate의 hydroxylation은 EDTA나 DETAPAC 에 대한 Fe^++의 결합비율이 2:1일 때 가장 크게 이루어졌으며 이러한 비율에서 벗어날때 hydroxylation속도는 감소되었다. ADP 또한 salicylate 의 hydroxylation 을 억제하였다. 여러 환원제 가운데 ascorbate는 Fe^+++의 환원과 iron에 의한 지질의 과산화를 가장 강력하게 촉진하였다. Fe^++와 ascorbate의 첨가에 따른 지질의 과산화는 Fe^+++와 ascorbate에 의한 것보다 훨씬 현저하였다. Fe^++또는 Fe^++와 ascorbate 의 상호반응에 의한 ferricytochrom c의 환원은 SOD에 의하여 뚜렷하게 억제되었으나, ascorbate 자체에 의한 ferricytochrom c의 환원은 SOD에 의하여 약간 억제되었다. 한편 cysteine,NADH와 giutathione중에서 cysteine에 의한 ferricytochrom c 의 환원만이 SOD 에 의하여 억제되었다. 이상의 결과로부터 iron의 산화와 환원을 억제 또는 촉진시키는 물질은 지질의 과산화를 억제하거나 촉진 시키므로 iron의 산화 및 환원과 지질의 과산화 사이에는 관계가 있을 것으로 사료되었다. 또한 이러한 반응에서 OH·같은 산소라디칼이 iron의 산화 및 환원에 따른 지질의 과산화를 초래하는 매개물질로서 작용할 가능성이 시사되었다. Iron is a reactive metal ion which is known to catalyze damages of cellular rnacrornolecules causrd by oxygen radicals and its reduction may play a major role in lipid peroxidation. The iron-catalyzed Hater-Weiss reaction to produce OH is catalyzed by iron and OH appear to participate as an initiator of lipid peroxidation. Ferrous(or chelated) ion will also initiate peroxidation of unsaturated fatty acids. This initiation may of cur via abstraction by a ferrous-dioxygen complex or alternatively may involve 0_2, H_2O_2 or other partially reduced oxygen species generated through fur-ther autoxidation reactions of the ferrous che-lates. Many studies have reported toxic effects of ascorbate on various biological materials including lipid and DNA peroxidation. In view of data suggesting that the effect of iron on lipid peroxidation is mediated by its oxidore-duction, reducing actiyity of reducing agents such as ascorbate may be the mechanism through which the toxic action of ascorbate is mediated. In the Present study, the effect of oxidore-ducticn of iron on tissue damages was inves-tigated in the presence of various reducing agents or iron chelators. These effects were studied with respect to generation of oxygen radicals during oxidation or reduction of iron in relation to the lipid peroxidation caused by iron. The effects of reducing agents or iron chelators on redox phenomenon of iron were also observed. Furthermore, the relationship between oxidoreduction of iron and lipid pero-xidation was studied. Lipid peroxidation of microsomes was increased with concentration of Fe^++, but Fe^+++ had little effect. In reaction medium of pH 7.4, Fe^++ was almost compte-tely autoxidized at 5 min after the reaction and during this process superoxide radical was formed. Lipid peroxidation of microsomes by Fe^++ was inhibited by SOD and catalase. EDTA or DETAPAC showed dual effects on lipid peroxidation by Fe^++ When proportion of these chelators to iron was 1:2, lipid peroxidation was enhanced but when this ratio is altered, lipid peroxidation was inhibited. ADP prevented lipid peroxidation by Fe^++ and stimulated that by Fe^+++, EDTA or ADP facilitated autoxidation of Fe^++ whereas DE-TAPAC inhibited. On the other hand, when proportion of EDTA or DEfAPAC to Fe^++ was 1:2, hydroxylation of sodium salicylate was maximum and fell off as this proportion was altered. ADP also prevented hydroxylation of salicylate by Fe^++ Among various reducing agents tested ascorbate had a most potent reducing power and also most remarkably facilitated lipid peroxidation by iron. Lipid peroxidation caused by interaction of Fe^++ and ascorbate was greater than that by interaction of Fe^++ plus ascorbate. Reduction of ferricyto-chrorne c was enhanced by ascorbate in a dose dependent manner, but other reducing agents showed little effect. Reduction of ferricytoch-rorne c by Fe^++ alone or Fe^++ plus ascorbate was signifi cantly inhibited by SOD. However, reduction of ferricytochrorne c by ascorbate alone was slightly inhibited by SOD. From these results obtained, it is suggested that oxidoreduction of iron plays the major role in tissue damages including lipid peroxidation caused by iron dependent reactions and there is the relationship between the oxidoreduction of iron and lipid peroxidation. Also, it appears that oxygen radicals such as OH·plays at least a partial role in initiating lipid peroxidation.

토끼 유리체에 주사한 세페핌에 의한 망막 독성

조호균,하상우 중앙대학교 의과대학 의과학연구소 2001 中央醫大誌 Vol.26 No.3

The present study was performed to determine the appropriate intravitreal dose of Cefepime in the rabbit. Fifteen nonpigmented rabbits were divided into 3 groups.The first group,200㎍ of Cefepime in 0.1ml of distilled water was injected into five rabbits'vitreous cavities of right eyes, while same amount of balanced salt solution was injected into those of left eyes. The second group, the same method was used but 400㎍ of Cefepime was injected. The third group,1000㎍ of Cefepime was injected while using the same method as the first and the second. For the injection, 30 gauge syringe was guided to the center of the vitreous through the pars plana without conjunctival incision. To prevent ocular pressure increase from the intravitreal injection anterior chamber paracentesis was done. To observe the change of the retina, electron microscopic examination was done after 1,3, and 7 days respectively. There were no significant changes in the control and 200㎍ of Cefepime injection groups. On the other hand, in the 400㎍ Cefepime and 1,000㎍ Cefepime injection groups, ganglion cell deneneration, axonal deneneration, vacuole formation, retinal pigment epithelial deneneration were shown concentration dependently. These changes emerged in the inner retina first and progressed to the outer retina as the time went on. According to the result of the rabbit experiment, the proper concentration of intravitreal Cefepime dose is inferred as 600㎍ for human vitreous cavity.

난소절제후 Estrogen을 투여한 흰쥐 대동맥에서 Protein Kinase C-α와 Fas 발현의 변화

이왕수,이상엽,안지현,송영빈,김학진,이광재,유재격,김상욱,김태호,김치정,류왕성 중앙대학교 의과대학 의과학연구소 2001 中央醫大誌 Vol.26 No.3

Estrogen is believed to decrease coronary artery disease. Protein kinase C-α(PKCα)appear to be important in signal conduction pathways. Estrogen treatment increases catalytic activity of PKCα,and activation of PKCαcan modulate estrogen receptor levels and responsiveness. And it was reported that activation of PKC can protect cells from apoptosis induced by Fas ligation. But the beneficial effect of estrogen on PKCαwas not clearly demonstrated. The objective of this study was to evaluate the role of PKCαafter ovariectomy and estrogen therapy in rat aorta. The results were summarized as below: 1. The significant pathological changes were not observed in the rat aorta irrelevant to ovariectomy and estrogen therapy. 2. The expression of Fas was decreased in the aorta of estrogen-treated rats than that of ovariectomized rats without estrogen therapy. 3. Increased expression of PKCαwas more marked in the aprta of estrogen-treated rats than that of ovariectomized rat without estrogen therapy. In conclusion,PKCαmay be important in signal conduation pathway on the effect of estrogen. Activation of PKCαby estrogen reduced Fas expression, suggesting that PKCαactivation may play a role in protection against atherasclerosis. Further studies are needed to elucidate the role of PKCαafter estrogen therapy.

자발성 뇌교출혈 환자의 예후에 관한 임상 분석

조재영,석종식,민병국,권정택,최덕영,황성남,김영백,박승원 중앙대학교 의과대학 의과학연구소 2002 中央醫大誌 Vol.27 No.1

Patients with spontaneous pontine hemorrhage very often develop setvere disturbances of consciousness,pupilary abnormalities, respiratory and motor. They have high mortality rate. Therefore, I analyzed the correlation between the Glasgow outcome scale(GOS)and clincial manifestations or computed tomographic(CT)findings in 48 patients with spontaneous pontine hemorrhage to clarify factors predicting the prognosis. I examined 48 Patients with spontaneous pontine hemorrhage; 33 males and 15 females, age 54.6±8.99(mean±S.D.;range 39 to 68)brought to our hospital between January 1995 and December 1999, retrospectively. Correlations between the clinical manifestations, CT findings and the GOS was assessed with multivariate regression analysis. The results were as follow: 1) Patients with the pontine hemorrhage were of 8.8% in those with intracerebral hemorrhage. The ratio of male and female was 33 to 15. The incidence of age is eqial to 40,50 and 60. Total mortality was 41.6%. 2) The poor prognostic factor were that; Glasgow coma scale(GCS)3∼8, irregular respiration. pupilary abnormality, quadriplegia, Brain CT typeⅠ(massive), hydrocephalus, extrapontine extension, Intraventricular hemorrhage(IVH). These clinical analysis should be useful in determining the level of care and future resuscitative efforts.

Heat Shock Protein Expression in Endotoxin Treated Renal Epithelial Cells

Park, Jee-Hyoun,Oh, Dong-Jin,Yu, Soo Jeong,Lee,Tae-Woo,Kim, Cha-Hyun,Cho, Jae-Young,Yu, Suk-Hee,Kang, Eung-Taek 중앙대학교 의과대학 의과학연구소 2002 中央醫大誌 Vol.27 No.3-4

Recent studies have reported that markedly increased concentrations of a number of different classes of protein are initially identified by the marked increase in their concentration in cells after various stresses including heat shock. In this study, putative interactions between apoptosis and heat-shock proteins disturbed by endotoxin as aseptic shock model were investigated. The direct cellular damages were assessed by the LDH release from the cytoplasm of the human tubular epithelial cells(HK-2 cells) after lipopolysaccharides(LPS) treatment. And the expressions of Bcl2 and BAX mRNA that had been employed as an index of apoptosis to assess by what extent apoptosis contributed to tubular cell damage and the expression of heat shock protein(HSP)90, 72 and 27 with the Bcl2/BAX ratio in septic shock model were studied also. LPS treatment let HK-2 cells release SDH markely(14.33+/-1.55 vs. 61.00+/- 2.65, p<0.01). LDH release was greater significantly from the cells that had not been heat preconditioned than that of heat preconditioned(61.00+/- 2.65vs. 41.33 +/- 3.21,p<0.05) LPS treatment itself did not up-regulated Bcl2 significantly. But the expression of Bcl2 was marked with heat preconditioning. The expression of BAX was increased with LPS treatment but did not increase significantly with heat preconditioning(165% vs. 1496%). We did not see any contribution of heat preconditioning on the expression of HSP90. HSP72 expression was slightly increased with LPS treatment. But the expression of HSP27 was more evident after preconditioning with LPS treatment HSP27 expression was evident after LPS treatment. This study showed that the heat preconditioning was able to provide protection on the human tubular epithlial cells from LPS treatment extensively. The protection from cytolytic damage and increase of Bcl2/BAX ratio was closely related with the increase of HSP72 and HSP27, especially with LPS treatment.

Sclerosing Peritonitis Presenting as a Huge Peritoneal Cyst : Two Cases Report

Ahn, Juhee,Kim, Chahyun,Lee, Taewoo,Choi, Jaeyoung,Park, Jongsun,Kang, Eungtaek,Yu, Suk Hee,Cha, Seong Jae,Lim, Hyun Muck 중앙대학교 의과대학 의과학연구소 2001 中央醫大誌 Vol.26 No.2

Though sclerosing peritonitis(SCP)is rare, it is a serious complication of continuous ambulatory peritoneal dialysis(CAPD) patients. The pathogenesis of SCP, which appears to be multifactorial, is unclear even now. We report on two patients wo had been diagnosed with SCP presenting as a hung peritoneal cyst. They were transferred from CAPD to hemodialysis(HD) because of ultrafiltration failure and intractable peritonitis. Abdominal CT showed a hung fluid-filled cyst in the peritoneal cavity. Because of intractable ascites and abdominal discomfort, exploratory lapartomy with cyst removal and adhesiolysis were performed. The pathology confirmed the diagnosis of SCP. The patients have remained healthy without any complications or further treatment.

허혈-재관류에 의한 흰쥐 간의 손상에 있어서 반응성 산소종의 역할

지경천,권년수,이희성,김상준,장선택 중앙대학교 의과대학 의과학연구소 1992 中央醫大誌 Vol.17 No.4

Increased generation of reactive oxygen species is thought to be a major cause of tissue in ischemia-reperfusion injury. Left and median lobes of rat livers were subjected to 20 minutes of ischemia followed by reperfusion for up to 120 minutes. Superoxide radical generation was enhanced to 338 μmol/minute/g tissue after 60 minutes of reperfusion,and 367 μmol/minute/g tissue after 120 minutes. Superoxide generation in the liver of the control animal was 260 μmol/minute/g tissue. The activity of xanthine oxidase, a superoxide radical-generating enzyme, was also elevated in the liver treated with ischemia-referfusion. These results indicate that xanthine oxidase-catalyzed reaction is an important source for the superoxide generation in rat liver treated with ischmia-referfusion. The activities of superoxide dismutase and catalase, enzyme responsible in removing superoxide radical and hydrogen peroxide, were measured. Cu, Zn-superoxide dismutase activity was significantly higher in reperfused liver after ischemia than in control. However, the activity of Mn-containing superoxide dismutase was significantly low in reperfusion. The extent of tissue damage by ischemia-reperfusion was evaluated by measuring lipid peroxidation. Thiobarbituric acid reactive substance was significantly elevated in the liver treated with 60 minutes of ischemia followed by 60 minute of reperfusion. These results suggested that increased reactive oxygen species and diminished activities of enzyme removing toxic oxygen species rendered the damages on the liver which was sujected to ischemia followed by reperfusion.

과배란유도시 난포성숙을 유도시키는 GnRH Agonist가 성선자극 및 호르몬 분비에 미치는 영향에 관한 연구

김중환,이상훈,배도환 중앙대학교 의과대학 의과학연구소 1992 中央醫大誌 Vol.17 No.3

Gonadotropin medications have been used successfully for three decades to stimulate ovarian follicular development in anovulatory patients and , more recently, in normal ovulatory women for assisted reproduction. In these patients, endogenous luteinizing hormone(LH) surge infrequently occureed and therefore the administration of human chorionic gonadotropin(hGG) is required to induce oocyte maturation and ovulation. In spontaneous ovulatory cycle, there is a surge of both luteinzing hormone and follicle stimulation hormone(FSH) at midcycle. But, hCG possesses mainly LH-like activity. In addition, hCG continues to stiumlate the follicles for days after ovulation has been completed due to its long half-life. The objective of this study was to evaluate the efficacy of Gonadotropin releasing hormone(Gn고) agonist to trigger the final follicular maturation in hormone secretions during the ovarian stiumlation. A single dose of decapepty 0.1mg subcutaneously were administered to 40 cycles and 10,000 IU hCG were intramuscularly administered to 38 cycles for triggering the final maturation of oocytes. Both groups underwent identical ovarian stimulation protocol and cycle monitoring. GnRH agonist effectively triggered LH and FSH surge, and which duration was similar that of spontaneous menstrual cycle. In contrast hCG triggered LH surge only, and which duration was longer than that of spontaneous menstrual cycle. No differences were observed in mean serum E_2 and progesterone concentration. Mature oocytes were recovered in all patients. In conclusion, single dose of GnRH-a is able to trigger and adequate midcycle LH/FSH surge, resulting n adequate oocyte maturation and fertilization.

Ouabain이 음경해면체평활근에 미치는 영향에 관한 실험적 연구

오충환,김세철 중앙대학교 의과대학 의과학연구소 1992 中央醫大誌 Vol.17 No.3

The effect of ouabain on smooth muscle of the corpus cavernosum itself and its effect on the action of adrenergic, cholinergic or non-adrenergic non-cholinergic neurotransmitters were observed in vivo using dogs as experimental animals and in vitro using isoloated corpus cavernosal strips from rabbit penis. A 21 gauge needle was placed into the cavernous space of the anethetized dog, and intracorporeal pressure(ICP) was measured; 1) before stimulation of the cavernous nerve(NS), 2) during NS and 3) during NS following intracorporeat injection of ouabain. The corpus cavernosal strip was suspended in an organ both containing 20ml of Krebs-bicarbonate solution main-tained at 37 The Krebs-bicarbonate solution was aerated with 95% oxygen and 5% carbon dioxide. One end of the cavernosal strip was fixed at the bottom of the bath and the other end connected to the force displacement transducer. When the stable tension level of the strip reached, drugs were added to the organ bath and the change of contractility of the strip was recorded on a polygraph. The resist were obtained as follows; 1. ICP before and during NS were 9.806.14mmHg(Mean±S.D.) and 107.80±15.76mmHg. ICP during NS following intracorporeal injection of ouabain was 37.00±12.39mmHg at 10 minutes after injection of ouabain 34.00±1.58mmHg at 50 minutes, 28.80±12.15 mmHg at 90 minutes and 28.40±10.55 mmHg at 130 minutes. There was a significal drop of ICP following intracorporeal injection of ouabain(p<0.01) but a significant change of ICP with the time elapsed after obtain injection was not found. 2. Ouabain (1×10^7M) increased the contractility of the isolated cavernosal strip from rabbit. In the pretreated state with tetrodotoxin(5×10^7M), contraction of the strip was induced by ouabain, but neither relaxation nor contraction occurred by additional nerve stimulation. So, ouabain might contribute to the contraction of cavernosal strip not by neuronal effect but by direct action on the smooth muscle. 3. 2-chloro-adenosine and Vasoactive Intestinal Polypepeide(VIP) showed a relaxing effect on the cavernosal strip but acetylcholine had both contraction and relaxing effect. Ouabain partly inhibited the relaxing effect of these neurotransmitter. Therefore, it is concluded that ouabain directly acts on the smooth muscle of the corpus cavernosum and contracts it. However, it seems that the contraction effect of ouabain is less stronger than the relaxing effect of the adenosine, VIP and acetylcholine.

소아 비폐색 환자의 수술 전후 비저항치 변화에 대한 연구

한병상,유태선,유영근,홍영호,김춘길,김훈 중앙대학교 의과대학 의과학연구소 1992 中央醫大誌 Vol.17 No.1

Nasal obstruction is one of the most common complaints in pediatric otolarygology. Generally nasal obstruction is caused by anatomic abnormalities of the nasal cavity, inflammation of the nasal from patient to patient. The size of the nasopharyngeal airway and adenoids on the symptom pharygeal wall has been asseaaed by clinical inspection with the posterior rhinoscopy. However, this inspection may be difficult to carry out in childern and has limited value in physiologic aspect. I can measeure the nasal obstruction objectively and raliably with rhinomanometry. 32 patients with nasal obstruction were evaluated preoperatively and postoperativeley. We compared the effects of the two types of surgery by measuring the total nasal resistance(TNR) of rhinomanometry (Rion SR-11) during inspiration. The results were as folloes ; 1) The group who undewent tonsillectomy, adenoidectomy and submucous diatermy had more significant improvement of symptoms than the group who underwent just tosillectomy and adenoidectomy(p<0.05). 2) The preoperative TNR of all the patients during inspiration was 0.360Pa/㎤/sec and 0.275Pa/㎤/sec in postoperative period(p<0.01). The group who underwent tonsillectomy and adenoidectomy had a preoperative TNR OF 0.377Pa/㎤/sec and postoperative TNR OF 0.292Pa/㎤/sec. The group who underwent tonsillectormy, adenoidectormy and submucous diathermy had a preoperative TNR of 0.348Pa/㎤/sec. This changed into a postoperative TNR of 0.261Pa/㎤/sec (p<0.01). 3) This difference of the TNR between preoperative group and postoperative group was statistically significant(P<0.01).