• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.203-211
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• 1999

목적: 일산화질소 (nitric oxide; NO)는 생식계를 비롯한 여러 생체내 기관에서 다양하고도 중요한 작용을 하는 것으로 알려져 있으며, 복강액은 난관내강과 연결되어 복강액 내의 세포 성분의 변화는 난관의 미세환경을 변화시켜 수정과 초기 배아 발생에 영향을 줄 수 있다. 본 연구는 배아 발생에 있어서 일산화질소의 역할을 이해하고 복강액 내의 NO농도 변화가 배아 발생에 미치는 역할을 조사하기 위해 수행되었다. 방법: 과배란시킨 1세대 잡종 암컷 생쥐 (C57BL${\times}$CBA/Ca)로부터 1세포기 배아를 얻어 10% synthetic serum substitute가 첨가된 modified human tubal fluid 배양액에서 4일 동안 체외배양하였다(대조군). 실험을 위해 이러한 배양조건에 sodium nitroprusside (SNP)를 $0{\sim}1mM$의 다양한 농도로 배양초기부터 첨가하거나, $200{\mu}M$ SNP를 2-, 4-, 8-세포기의 각기 다른 배아시기에 첨가하였으며, 복강경수술을 받는 42명의 여성으로부터 채취한 복강액을 SSS대신 단백질원으로 사용하여 포배아까지의 배아 발달율을 관찰하였으며, 복강액 내의 NO농도를 Griess방법에 의해 측정하였다. 배아의 apoptotic body는 H33342 염색법으로 조사하였으며 배아 발달율은 3회 이상 반복 실험한 결과의 mean${\pm}$SEM으로 나타내었다. 결과: SNP는 농도에 의존적으로 배발생을 억제하였으나 배아 단계에 대한 특이성은 관찰할 수 없었으며, 특히 $100{\mu}M$ 이상의 고농도의 SNP는 2-세포기 단계에서 배아 발생을 정지시켰다. 또한 단백질원으로 복강액 이용시 배 발생율은 복강액 내의 NO 농도에 따라 현저한 차이가 발견되었으며, $2.5{\mu}M$이상의 NO를 함유한 복강액에서 배양한 배아의 발생율은 현저하게 감소하였다. cGMP analogue인 8-bromo-cGMP를 배양액에 첨가시 배아 발생에는 변화가 없었으며, SNP에 의해 배발생이 정지된 2-세포기 배아에서 apoptotic body를 발견할 수 없었다. 결론: 이상의 결과로 보아 NO는 고농도에서 배아 발생을 저해하며, 복강액 내의 NO와 같은 성분의 변화는 배아 발생에 유해한 효과를 유발할 것으로 사료된다. 이러한 NO의 배아 발생 억제효과는 cGMP로 중재되는 경로나 apoptosis유발과는 관계가 없는 것 같다.

• Advances in pediatric surgery
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• v.13 no.2
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• pp.127-134
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• 2007

Meckel's diverticulum is the most common congenital anomaly of gastrointestinal tract in children. The incidence of complicated Meckel's diverticulum is about 4 %. The major complications of Meckel's diverticulum are bleeding, intussusception, obstruction and perforation. The aim of this study was to investigate the clinical manifestations and the role of laparoscopic surgery in complicated Meckel's diverticulum in children. We retrospectively reviewed the medical records of 19 patients with complicated Meckel's diverticulum who underwent operation at Asan Medical Center between Jan. 1990 and Apr. 2007. Male to female ratio was 11:8, and median age was 1 year (1 day-13 years). The most frequent symptom was hematochezia (68%), followed by irritability or abdominal pain (16%), vomiting (11%), and abdominal distension (5%). Two operative procedures were performed; small bowel resection with anastomosis (68%) and diverticulectomy (32%). The operation proven complications of the Meckel's diverticulum were bleeding (68%), intussusception (16%), perforation (11%) and obstruction (5%). Ectopic tissues found by postoperative pathologic examination were gastric (84%) and pancreatic (11%). Hospital stay after laparoscopic operation for bleeding Meckel's was 5 days (median) and average first postoperative feeding was 1.5 days. On the contrary, hospital stay for open surgery was 7 days and first feed was 3 days. In summary, the most common compliation of Meckel's diverticulum in children was bleeding and ectopic gastric tissues were present in 84%. Laparoscopic procedure seemed to be useful for diagnosis as well as for definitive treatment.

• Journal of Gastric Cancer
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• v.10 no.1
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• pp.19-25
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• 2010

Purpose: Laparoscopy-assisted gastrectomy (LAG) is gaining wider acceptance as a minimally invasive treatment for early gastric cancer, but the safety, efficacy and clinical benefits of this type of surgery are still unclear. The purpose of this study is to compare laparoscopy-assisted gastrectomy (LADG) and conventional open distal gastrectomy (CODG) for early gastric cancer (EGC) according to the changes of the postoperative nutritional status and acute inflammatory reaction. Materials and Methods: Eighty seven patients with EGC and who underwent a LADG between March 2006 and May 2009 at Daegu Catholic University Hospital, was enrolled. Over the same period, we enrolled 30 patients who underwent CODG and they were confirmed to have EGC from their pathology. The clinico-pathological features and serologic parameters were evaluated from the medical records and then retrospectively analyzed. Results: There were no differences in the preoperative white blood cell (WBC), C-reactive protein (CRP) level, albumin level, the T4/T8 ratio and the other clinical data between the two groups. The total WBC counts gradually increased and they were significant lower at the $1^{st}$ and $3^{rd}$ postoperative days in the LADG group than that in the CODG group (P=0.001 and 0.008, respectively). The postoperative CRP levels were significantly lower at postoperative $5^{th}$ day in the LADG group (P<0.001). The postoperative albumin and T4/T8 ratio gradually decreased, and the T4/T8 ratio was significantly higher at the $3^{rd}$ postoperative day in the LADG group compared to that in the CODG group (P=0.003). Conclusion: This study demonstrates that the LADG has less of an influence on an acute inflammatory reaction than does CODG. Therefore, it is one of the safe and feasible procedures for the treatment of early gastric cancer.

• Journal of Chest Surgery
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• v.39 no.3 s.260
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• pp.255-259
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• 2006

The operation for esophageal cancer is both complex and challenging, and may be associated with significant morbidity and mortality compared to other oncologic surgeries. Minimally invasive surgeries have been applied on various kinds of surgery to enhance better recovery with minimal surgical complications. But for the esophageal cancer, it has not been actively applied yet. With improvement in instrumentations and increasing experience with endoscopic surgical techniques, minimally invasive surgical approaches to esophageal cancer are being explored to determine feasibility, results and potential advantages. We experienced eight cases of minimally invasive surgery for esophageal cancer and report here focusing on surgical techniques and tips.

• Advances in pediatric surgery
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• v.13 no.2
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• pp.203-211
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• 2007

A nationwide survey on acute appendicitis (AAP) was undertaken among members of the Korean Association of Pediatric Surgeons. The members were required to complete a questionnaire and the case registration form for each patient during the 6 months period from the $1^{st}$ October, 2005 to $31^{st}$ March, 2006. Questionnaires were collected from 23 members. Four hundred seventy six patients were registered from 21 hospitals where the members were working. The male to female ratio was 1.67:1. Average age was 9 years and 5 months (range 21 months-20 years). Operations were performed on average 10.4 hours (range 1-230 hours) from arrival at hospital. The average operation time was 59.1 minutes. The average admission days were 5.8 days (range 2-45 days). The most frequent symptoms were abdominal pain (95.1 %), vomiting (50.6 %) and fever (43.7%). The average duration of symptoms was 42.2 hours (range 1 hour-22 days). Leukocytosis (WBC count > 10,000) was found in 85.9%. The most popular diagnostic tools were ultrasonography and CT. Open surgery was performed in 72.1 % and laparoscopic surgery in 27.5 %. Two laparoscopic surgeries were converted to open surgery (0.4 %). Simple appendicitis was found in 54.5 % and complicated appendicitis such as abscess, gangrenous change and perforation in 45.5%. According to the questionnaires 12 hospitals were performing open surgery only in all patients. Four hospitals were performing laparoscopic surgery in all patients. Seven hospitals are performing both surgical methods according to surgeon or occasion. Regarding the use of antibiotics in acute appendicitis, three kinds of antibiotics were used in 40 % of total simple appendicitis patients. The results showed the trend of management in acute appendicitis in Korea. Especially it is necessary for the members to discuss the use of antibiotics for prophylaxis in the simple appendicitis.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.238-245
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• 2009

Purpose: Treatment strategies for early gastric carcinoma (EGC) should be based on achieving a complete cure, but clear indications for limited surgery have not been established. We investigated surgical outcomes for early gastric cancer to determine the optimal? treatment strategy for EGC. Materials and Methods: Subjects included 881 patients who underwent curative surgery for EGC between 1986 and 2003. Retrospective uni & multi-variate analysis for prognostic factors, factors affecting lymph node metastasis, and risk factors for cancer recurrence were analyzed. Results: In multivariate survival analyses, age, operation method, macroscopic appearance and lymph node stage proved to be independent prognostic factors. Lymph node metastasis, depth of tumor invasion, tumor size, lymphatic and venous invasion were also significant risk factors in multivariate analyses. In multivariate analyses for cancer recurrence, depth of tumor invasion and lymph node metastasis proved to be significant risk factors. Conclusion: Appropriate surgical treatment with lymph node dissection is necessary for EGC patients with risk factors for lymph node metastasis.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.732-736
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• 2006

Purpose : Numerous methods exist for diagnosing nonpalpable testis in treatment of cryptochidism. However, there is no clinically established data for the rational diagnostic tool of nonpalpable testis in terms of expenses. We tried to establish a current conventional diagnostic course of nonpalpable testis. We then evaluated the efficacy of ultrasonography, physical examination under general anesthesia and laparoscopy for diagnosing nonpalpable testis. Methods : Between March 2000 and February 2005, 103 boys(129 testes) with undescended testes were treated in our department. There were 31 testes(24.0%) that were not palpable at physical examination. These patients were evaluated with ultrasonography and repeated physical examination under general anesthesia. In the cases where testes could not be detected with ultrasonography and physical examination under general anesthesia, laparoscopy was performed to diagnose nonpalpable testis. Results : In 31 cases of nonpalpable testis, 13 testes were detected with ultrasonography and 15 testes became palpable with physical examination under general anesthesia. All of the remaining 16 nonpalpable testes were confirmed with laparoscopy. Conclusion : Physical examination under general anesthesia was superior to ultrasonography in making a diagnosis of nonpalpable testis. Ultrasonography and physical examination under general anesthesia could reduce the incidence of diagnostic laparoscopy. Therefore, it is recommended that ultrasonography, physical examination under general anesthesia and laparoscopy must be performed conventionally in order to diagnose nonpalpable testis.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.7
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• pp.685-696
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• 2011

An efficient laparoscope manipulator robot was designed to automatically control the position of laparoscope via a passive joint on end-effector position. The end position of the manipulator is controlled to have corresponding velocity defined in the global coordinate space using laparoscopic visual information. Desired spatial position of laparoscope was derived from detected positions of surgical instrument tips, then the clinical viewing plane was moved by visual servoing task. The laparoscope manipulator is advantageous for automatically maintaining clinically important views in the laparoscopic image without any additional operator. A laparoscope is mounted to a holder which is linked to four degree of freedom manipulator via universal joint-type passive rings connection. No change in the design of laparoscope or manipulator is necessary for its application to surgery assistant robot system. Expanded working space and surgical efficiency were accomplished by implementing slant linking structure between laparoscope and manipulator. To ensure reliable positioning accuracy and controllability, the motion of laparoscope in an abdominal space through trocar was inspected using geometrical analysis. A designed laparoscope manipulating robot system can be easily set up and controlled in an operation room since it has a few subsidiary devices such as a laparoscope light source regulator, a control PC, and a power supply.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.518-526
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• 2008

The fuzzy self-tuning PID controller is a PID controller with a fuzzy logic mechanism for tuning its gains on-line. In this structure, the proportional, integral and derivative gains are tuned on-line with respect to the change of the output of system under control. This paper deals with two types of fuzzy self-tuning PID controllers, rule-based fuzzy PID controller and learning fuzzy PID controller. As a medical application of fuzzy PID controller, the proposed controllers were implemented and evaluated in a laparoscopic surgery robot system. The proposed fuzzy PID structures maintain similar performance as conventional PID controller, and enhance the position tracking performance over wide range of varying input. For precise approximation, the fuzzy PID controller was realized using the linear reasoning method, a type of product-sum-gravity method. The proposed controllers were compared with conventional PID controller without fuzzy gain tuning and was proved to have better performance in the experiment.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.218-221
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• 2006

This paper reports on a Realtime OS based motor control system for laparoscopic surgery robot which enables telesurgery and overcomes shortcomings with conventional laparoscopic surgery. The system has a conventional master-slave robot configuration and the control system consists of joint controllers, host controllers, and power units. The robot features (1) a compact slave robot with 5 DOF (Degree Of Freedom) expanding the workspace of each tool and increasing the number of tools operating simultaneously, and (2) direct 1:1 correspondence in the joint of master and slave robot that simplifies control algorithm and enhances reliability. Each master, slave and GUI (Graphical User Interface) host has a dedicated RTOS (RealTime OS), RTLinux-Pro (FSMLabs Inc., U.S.A.) Each master and slave controller set pair has a dedicated CAN (Controller Area Network) channel for control and monitoring signal communication. Total 4 pairs of the master/slave manipulators as current are monitored by one host controller for operation monitoring and higher level motion control. The system showed acceptable performance in both position control precision and master-slave motion synchronization and is now under further development for better safety and control fidelity for clinically applicable prototype.