기업지배구조의 변화가 주주의 부에 미치는 영향

조광현,안희영,Rifat Gorener,최성호 한국산업경제학회 2010 산업경제연구 Vol.23 No.6

이 논문은 국내 상장기업을 대상으로 기업지배구조 등급의 변화가 주주의 부에 미치는 영향을 사건 연구 방법을 통해 실증분석하였다. 본 연구의 주요결과를 요약하면 다음과 같다. 첫째, 사건연구를 통한 분석결과 지배구조 등급변경의 공시 사건일(event window)에 측정한 누적평균초과수익률(CAAR)은 통계적으로 유의한 수준에서 음(-)의 값으로 나타났다. 이는 지배구조등급의 변화가 일반적으로 시장참여자들에게 해당기업에 대한 위험요인으로 받아들여지고 있음을 나타낸다. 둘째, 기업지배구조 등급의 변경을 상향조정과 하향조정으로 구분하여 CAAR을 검증한 결과, 등급의 하향조정시 CAAR은 통계적으로 유의한 수준에서 음(-)의 값이 나타났다. 셋째, 기업지배구조의 등급 변화가 취약등급에서 보통이상의 등급으로 상향조정된 경우 CAAR 값은 양(+)의 값이 나타났고, 보통 이상의 등급에서 취약등급으로 하향 조정된 경우에는 CAAR 값들은 통계적으로 더욱 유의하게 음(-)의 값이 나타났다. 이 결과들은 기업지배구조의 변화가 시장에 적절히 반영되고 있음을 의미하며, 지배구조등급의 개선이 주주의 부를 높이고 지배구조등급의 악화가 주주의 부를 감소시킬 수 있음을 나타낸다. 넷째, 기업특성을 통제한 후 지배구조 등급의 변화와 초과수익률(CAR)간의 관계를 살펴본 회귀분석의 결과에서도 전체 표본을 이용하였을 때 등급의 상향 변경이 초과수익률과 유의한 양(+)의 상관관계를 가지는 것으로 확인되어, 시장참여자들이 지배구조등급의 변화에 민감하게 반응함이 나타났다. 또한 지배구조등급이 취약등급에서 보통이상의 등급으로 상향조정되는 경우 CAR가 유의하게 상승하는 것으로 나타났으며 계수 값 또한 다른 등급의 조정변화보다 크게 나타났다. 이러한 결과는 취약등급을 기준으로 이루어진 지배구조등급의 상하향이 시장에서 더 큰 정보로 받아들여지고 있음을 의미한다. 본 논문의 결과를 종합해보면 지배구조가 좋은 기업일수록 기업의 가치가 높게 평가되고, 이 결과는 기존의 연구결과들과 일치한다. This paper examines the effect of the changes in the rating group of the company's governance index on the wealth of stockholders. Specifically, this paper investigates the announcement effect of governance index group changes which is measured by the cumulative abnormal returns to stockholders of rating group-changed company. The empirical results are as follows. First, the empirical test indicates that on average the cumulative abnormal return (CAAR) is significantly negative in various event windows. This finding implies that the announcement of governance rating group changes plays as an additional risk factor to stockholders, resulting in a lower return. However, changes in corporate governance ratings have different results depending on whether the rating change is upgrade on not. While the downgrade of governance rating results in a significantly negative abnormal returns to the stockholders, the CAAR is positive when there is an upgrade of governance rating. Further more, if the governance rating falls to the weakest group, the cumulative abnormal return is significantly negative. On the other hand, the upgrade from the weakest group results in a significantly positive CAR to the stockholders. Finally, after controlling the firm specific characteristics, the regression analysis confirms our previous results. These results are consistent with the literature that the good governance practice increases the value of firm.

팔로사징증의 근치 수술에 관한 임상적 고찰

조광현 대한흉부심장혈관외과학회 1991 Journal of Chest Surgery (J Chest Surg) Vol.24 No.7

The surgical treatment of tetralogy of Fallot [TOF] was initiated by Blalock and Taussig in 1945 with the establishment of the subclavian artery to pulmonary artery anastomosis. In an imaginative and daring effort, in 1954, Lillehei and collaborators [1955] using controlled cross-circulation, carried out the first intracardiac repair of TOF by closing the ventricular septal defect [VSD] and relieving the pulmonary stenosis under direct vision. Nowadays, total correction is the ideal operation for treatment of TOF and is accomplished with extracorporeal circulation. And the results of surgery for TOF have steadily improved over the years, thanks to important contributions of many surgeons. Nevertheless because of its protean physiologic and anatomic presentation, TOF continues to offer challenges to cardiologist and cardiac surgeons. Thirty two cases of TOF have undergone total corrective surgery using extracorporeal circulation in the Department of Thoracic & Cardiovascular Surgery, Pusan Paik Hospital, Inje University, from Oct. 1985 to Feb. 1990. Clinical considerations were applied to these cases and the results were obtained as follows. 1. The heart lung machine used for extracorporeal circulation was SarnsO 7000, 5-head roller pump, and the number and type of oxygenators were 10 of bubble type and 22 of membrane type. The mean bypass time was 148.9 minutes and the mean aortic cross clamp time was 123.8 minutes. The GIK [glucose-insulin-potassium] solution was used as cardioplegic solution for myocardial protection during operation. 2. 20 cases were male and 12 were female, the mean age was 8 years old and the mean body weight was 25Kg. 3. The preoperative symptoms were cyanosis [29 cases], squatting [27 cases] and etc. The mean values of preoperative Hb., Hct., and SaO2 were 16.5 gm /dl, 50.3%, and 78.5%. 4. Combined anomalies were noticed in 16 cases [50%]. Among them 10 cases were PFO and 6 cases were ASD. 5. The degree of aorta overriding were 25% in 5 cases, 25 ~ 50% in 22 cases and above 50% in 5 cases. The dPA/Ao [ratio of diameter of pulmonary artery trunk to ascending aorta] were below 25% in 5 cases, 25 ~ 50% in 10 cases, 50 ~ 70% in 6 cases and above 75% in 11 cases. 6. The types of RVOT [right ventricular outflow tract] stenosis were valvular and infundibular in 14 cases [43.6%], diffuse hypoplastic type in 12 cases [37.5%], infundibular in 5 cases, and valvular and supravalvular in 1 case. 7. One stage radical corrective surgery was applied to the all cases. In widening of the RVOT, 3 types of patches were used: MVOP [monocusp ventricular outflow patch, Polystan BioprosthesesO] in 3 cases, knitted Dacron vessel patches in 2 cases, and double layer with bovine pericardium and woven Dacron prosthesis in 26 cases. 8. Postoperative complications were occurred in 15 cases. Among them, low output syndrome were occurred in 10 cases [31.3%] and 2 of them were expired postoperatively.

32세 여자 환자의 얼굴에 발생한 단단한 저색소반

조광현 대한피부과학회 2012 대한피부과학회 학술발표대회집 Vol.64 No.1

절제폐(切除肺)에서 본 폐결핵병소(肺結核病巢)의 X선상(線像)의 특징(特徵)에 관(關)한 연구(硏究)

조광현,Cho, Kwang Hyun 대한흉부심장혈관외과학회 1976 Journal of Chest Surgery (J Chest Surg) Vol.9 No.2

The cellular change of the pulmonary tuberculous lesions may be divided into two groups,exudative and proliferative form by their course and fate. In the most cases, the patients usually have very much complex type of cellular changes. Therefore, the shadows of the chest films in pulmonary tuberculosis are also much variable in nature. And Daniel said that knowledge of the pathology of tuberculosis and an appreciation of the method of progression and healing are essential to proper interpretation of the films. Author, having reviewed 33 cases of resected tuberculous lung obtained in N.M.T.H. for one year from Oct. '75 to Sep. '76 by surgical managements, classified the Pathological findings such as: 1) caseation only, 2) tuberculoma, 3) atelectatic lung 4) cavitary lesion and 5) atelectasis with cavity, and examined the relationship between the roentgenological characteristics of the chest films and the pathological process of tuberculous lesions of the resected lungs, The result were obtained as follows. (1) Tuberculoma was commonly appeared in $S_2$ segment in right and $S_6$ segment in left. (2) Atelectasis and destroyed lung were more commonly appeared in left lung than right, and their containing rate of cavity was 82%. (3) Cavities were mostly appeared in $S_1$ and $S_2$ segments of both lung and the appearance-rate of cavity on $S_6$ segment was higher in left than right. And among the cavitary lesions of the resected lung, cavity was not seen in the preoperative chest films in 22%. (4) The configuration, thickness and sharpness of the walls of cavities, which revealed the cavitary shadows in the preoperative chest films, were mostly depended on the degree of increased collagenous fiber of the wall, existence of perifocalitis, and more or less of the caseous masses on the inner surface of the cavity wall.

폐과오종 치험 3례

조광현,박동식,홍숙희,Cho, Kwang-Hyun,Park, Dong-Sick,Hong, Sook-Hee 대한흉부심장혈관외과학회 1982 Journal of Chest Surgery (J Chest Surg) Vol.15 No.2

The term hamartoma was first used by Albrecht to describe what he considered to be localized errors of development involving one or more tissue native to the organ of origin. The definition was meant to encompass not only abnormal local growth rate, but also the spatial arrangement, relative proportions and degree of the component tissue. But lately the major conclusions are that this group of lesion is neoplastic than developmental in origin. The Importance of pulmonary hamartoma is that they are relatively common among the benign tumor of the lung, but they usually present as asymptomatic coin lesion on chest x-ray film and were find out In routine check up and frequently mimic clinically the more common lung tumor such as cancer. Recently, we have experienced three cases of pulmonary hamartoma which were all discovered during routine chest film check up for certificate of health and evaluation of other disease. All of these were surgically resected with good result. Among the operations, one of these was mass enucleation and the others were lobectomy of lung involved by the mass.

흉선절제로 치료한 중증 근무력증

조광현 대한흉부심장혈관외과학회 1985 Journal of Chest Surgery (J Chest Surg) Vol.18 No.4

Myasthenia gravis is a neuromuscular transmission disorder characterized by fatigue and weakness of voluntary muscles. Although the pathogenesis is known as reduction of available acetylcholine receptors at neuromuscular junctions by autoimmune attack, the thymic role in myasthenia gravis is still unclear and under investigation. But thymectomy in the management of myasthenia gravis has become increasingly important since the first successful operation with remission of symptoms in 1939 by Blalock. From January 1983 to June 1985, authors performed 17 thymectomies for patients with myasthenia gravis. Among them, 12 patients were free from thymoma [Croup A] and 5 were coupled with thymoma [Group B]. The results were as follows: 1] Sex distribution was 11 females and 6 males. Mean age of the patients was 32.2 year old. Sex and age distribution by the Group A and B are shown Table 1. 2] Clinical manifestations of ocular symptoms were seen in 5 patients [88.2%], extremity weakness in 13 patients, bulbar weakness in 12 patients and dyspnea in 6 patients. According to the Osserman`s classification, 5 patients were in group IIA, 6 in IIB and 6 in IIC. 3] Pre-operatively, all patients were positive response to the anti-cholinesterase test and 12 patients [92.3%] revealed positive findings in electromyography [EMC] which was done in 13 patients. 4] The postoperative complications were respiratory distress in 3 patients, myasthenic crisis in 2 patients and wound disruption in one patients. 5] Pathologic examination of the thymus showed hyperplasia in 10 patients [90%] and thymoma in 5 patients, of which 4 were mixed type with invasion to the adjacent tissues and one lymphocytic type without invasion. Normal thymus was noticed in only 2 patients. 6] In postoperative evaluations, among the 12 patients c free from thymoma [Group A], complete remission of symptoms was noticed in 3 patients and improvement in 7 patients. But among the 5 patients coupled with thymoma [Group B], only one patients showed improvement [Table 8]. Therefore, remission and clinical improvement were noticed in 11 patients [64.7%] of the all and complete remission was noticed in 3 patients [17.6%].

St. Jude Medical 판을 이용한 심판막 치환술의 성적

조광현 대한흉부심장혈관외과학회 1992 Journal of Chest Surgery (J Chest Surg) Vol.25 No.3

A 6 year experience with the bileaflet St. Jude Medical valve is reported. Between Feb. 1986 and Dec. 1992, 68 patients received 87 such valves[36 mitral, 13 aortic, and 19 double mitral-aortic valve replacements]. The results are summarized as follows 1. There were 35 male and 33 female patients ranging in age from 17 to 55 years the mean age of 35.3 $\pm$ 9.7 years. 2. The mean aortic clamp time[ACT] of the MVR, AVR and DVR groups were 91.5$\pm$16.4, 117.2$\pm$28.7 and 165.5$\pm$24.1 minutes. The mean total bypass time [TBT] of the MVR, AVR and DVR groups were 112.8$\pm$19.5, 134.7$\pm$31.4 and 192.2$\pm$28.5 minutes. 3. Eighty seven valves were used [55 mitral site, 32 aortic site]. 31mm[20], 33mm[15], 29mm[15], 27mm[2], 25mm[2] and 35mm[1] were used in mitral site and 23mm[13], 21mm[8], 19mm[7] and 25mm[4] were used in the aortic site. In the DVR, there were valve combinations such as 4 cases of M[29mm]-A[19mm], 4 of M[31mm]-A[23mm], 3 of M[33mm]-A[23mm] and others. 4. Preoperative NYHA functional classes were II [3 cases], III [46 cases], IV[19 cases] and improved to I [52 cases] and Il [13 cases] postoperatively. 5 Early postoperative complications were occurred in 15 cases[2Z.l%] and there were LOS in 5 cases[7.4%], arrythmia [3 cases], wound infection [2 cases], hepatitis [2 cases], sudden cardiac arrest [2 cases] and postoperative bleeding [1 case]. The early hospital death was occurred in 3 cases[4.4%] with LOS [1 case] and sudden cardiac arrest [2 cases]. 6. Mean follow-up time of survival cases[65 cases] was 31.3$\pm$21.9 months and the total follow-up time was 169.8 patient-years. Late postoperative complications were occurred in 4 cases[2 thromboembolism, 1 paravalvular leak, 1 thromboembolism br paravalvular leak, 1 valve endocarditis] with the occurrence rate as 2.35% per patient-years. Reoperation was performed in 2 cases [1 paravalvular leak, 1 left atrial thrombus] and there was one [1.5%] late valve related death. Therefore the 6 year complication free rate was 90.6% and 6 year actuarial survival rate was 98.3$\pm$1.7%. On the basis of this experience and the results, SJMvalve appears to be one of the best performing mechanical prosthesis currently available, in terms of both hemodynamics and lower complications with warfarin antioagulation.

폐의 선천성 낭포성 유선종치험 2례

조광현 대한흉부심장혈관외과학회 1985 Journal of Chest Surgery (J Chest Surg) Vol.18 No.4

The congenital cystic adenomatoid malformation [C.C.A.M.] of the lung is a rare lesion consisted of multiple cysts in the pulmonary parenchyma lined cuboidal or columnar epithelium. The C.C.A.M. presents clinically in three ways:[1] stillborn or perinatal death, [2] progressive respiratory distress in the newborn, and [3] acute and chronic pulmonary nfections in the older infant and child. We recently experienced two cases of C.C.A.M. of the lung, and have good surgical results. The first case was 29 days old male and the second case was 16 month old female who have been suffered from severe respiratory difficulty and pulmonary infection repeatedly each other. The lobectomies were performed, and the postoperative course was uneventful.

5년간 개심술 600예에 관한 검토

조광현 대한흉부심장혈관외과학회 1991 Journal of Chest Surgery (J Chest Surg) Vol.24 No.4

Surgical treatment of congenital and acquired heart disease preceded the development of accurate techniques for diagnosis, heart lung machine and cardiopulmonary bypass, intraoperative myocardial protection, operative techniques and cardiac anesthesia. For 5 years from Sep. 1985 to Sep. 1990, six hundred cases of open heart surgeries [OHS] were performed in the department of Thoracic & Cardiovascular Surgery, Pusan Paik Hospital, College of Medicine, Inje University. The results were summarized as follows. 1. The annual number of OHS[cases per year] was above 100 since 1987, and the increasing rate of cases was 23.5% per year since 1986. 2. Among the total 600 cases, there were 470 cases of congenital heart diseases and 130 cases of acquired. Age range of the congenital patients was 8 months to 44 years with the mean age of 10 years, and acquired patients was 16 to 56 years with the mean age of 36 years. 3. Among the 470 congenital anomalies, there were 429 cases of acyanotic and 41 cyanotic patients. Totally, VSD was 286 cases[60.6%], ASD 103 cases[21.9%], TOF 35 cases [7.4%], PS 20 cases [4.1%], ECD 12 cases [2.0%], Ebstein`s anomaly 3 cases [0.6%], Valsalva sinus rupture 3 cases [0.6%] and others. The appropriate one stage radical operations were applied to the all congenital cases with the result of 2.6% immediate postoperative hospital mortality rate. 4. Among the 130 acquired cases, there were 122 cases of valvular heart diseases, 6 of heart tumors [5 myxoma, one malignant histiocytoma], one of LA thrombus and one of annuloaortic ectasia. Cardiac tumors and LA thrombus were removed through the atrial septal approach. Bentall procedure was adopted to the annuloaortic ectasia case. AVR, MVR and TVA [DeVega procedure] were applied to 120 valve diseases, and there were also one of OMC and one of MVA[Jerome-Kay procedure]. 5. Among the 120 valve replacement cases, there were 87 of single valve replacement cases [AVR: 8, MVR: 79], 11 of double valve replacement [AVR+MVR: 11], 12 of MVR+TVR and 10 of MVR+AVR+TVA. The total number of implanted prosthetic valves were 141. In MVR, 45 of St. Jude Medical valves, 63 of Carpentier-Edward valves and 4 of Ionescu-Shiley valves were used. In AVR, 18 of St. Jude Medical valves and 11 of Carpentier-Edward valves were used. in MVR, 29mm and 31mm sized valves were used mostly and In AVR, 23mm sized valves were used mostly. 6. Postoperatively many kinds of complications were occurred. Among them, wound problems [30 cases], low output syndrome [29 cases], arrhythmia [20 cases], pleural effusion and pneumothorax [13 cases] were occurred frequently. The postoperative immediate hospital mortality was 3.0% in total [congenital 2.6%, acquired 4.6%].

Zn2+에 의한 Tolaasin의 용혈활성 저해효과

조광현,김영기,김성태 한국응용생명화학회 2006 Journal of Applied Biological Chemistry (J. Appl. Vol.49 No.4