치과용 니켈-티타늄 합금의 갈바닉 부식

최창혁,최기열,이중배 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

The purpose of this study was to evaluate the galvanic corrosion behavior of NT by coupling with other dental alloys in artificial saliva. The variation of galvanic current and common potential (mixed potential) were monitored as a function of time, and interpreted in terms of the electrochemical properties of each alloy. The effects of adding some constituents such as acid or chloride to the ordinary composition of artificial saliva were also estimated. For most cases of coupling, the significant current was observed only at early stage for several seconds or several minutes, then gradually diminished. The current value was affected by the excessive amount of acid or chloride added to artificial saliva, depending on their aggressiveness on each alloy ; the current was increased in the couples with HG, LG, VT, and decreased in the couples with AM and G2. The results were more complicated in the couples with AP and TC, where some mixed reaction occurred. The common potential was always between two corrosion potentials of alloys involved in the couple, and did not exceed the breakdown potential of alloy acted as anode except the case of coupling with AM in acid-containing artificial saliva. The coupling with AM was found to be the most susceptible to galvanic corrosion.

하악골에서 발생한 원발성 Ewing씨 육종 1례

고중화,전상훈,오영택,최진혁 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.2

우리 민속음악의 현대화에 관한 연구

김현중 / 김용래 / 윤경구 / 최종석 / 권혁남 공주교육대학교 초등연구원 1978 公州敎大論叢 Vol.14 No.2

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선인장 양심실 보조장치의 설계 및 임상적용을 위한 평가

민병구,박찬영,최재순,이혁수,황창모,김삼성,윤걸중,김종원,선경,이경갑,정종태,김원곤 제주대학교 인공심장이식연구소 2001 인공심장 연구 Vol.2 No.1

현재 개발되고 있는 맥동형 이식형 인공심장은 완전이식형 인공심장과 좌심실보조장치 뿐이다. 좌심실보조장치를 장착한 환자의 10~15%가 우심실의 보조를 필요로하고 완전이식형 인공심장의 장착을 위해서는 자연심장을 제거해야하는 상황에서 이식형 양심실보조장치에 대한 필요성이 대두되고 있다. 본 연구진은 완전이식형 인공심장으로 개발된 한국형 인공심장을 개선하여 양심 실 보조장치를 개발하였다. 양심실보조장치는 이동형 작동기식 미케니즘을 이용하고 있으며 에너지 변환장치와 감속기로 구성된 작동기와 혈액주머니, 그리고 내장형 제어기로 구성되어 있다. 선인장 펌프로 명명된 KAH350은 캐뉼라의 연결을 위한 커넥터를 포함하여 길이 177mm, 폭 164mm, 높이 67 이고 무게 780g이며 최대 심박출량은 5L/min 이다. 양심실보조장치로 개발된 선인장펌프는 좌심실보조장치로도 응용이 가능하다. 이식적합성과 생체적합성을 평가하기 위하여 좌심실보조장치로 5회, 양싱실보조장치로 6회의 동물실험을 수행하였다. 각각 최장 28일간 생존하였으며 11회의 동물실험중 장치의 결함에 의한 것이 3회 있었는데 이들은 모두 전자장치의 결함과 방수처리문제였다. 현재 이식적합성과 일박출량을 향상시킨 KAH400모델이 개발중이다. The types of pulsatile implantable artificial hearts that are on the way of development and have been developed are totally implantable artificial heart and implantable left ventricular assist device (LVAD). Approximately 10% to 15% of all patients Implanted with wearable VADs have required right heart support with another device. And it is reluctant to patient who should remove his or her own heart to be implanted with total artificial heart. These situations drive the development of implantable bi-ventricular assist device (BVAD). The Korean BVAD was develophed by modifying the moving actuator type Korean artificial heart. This electro-mechanical BVAD comprises actuator including energy converter and reduction gear train, blood sacs, and internal motor and energy controllers. The KAH350 which is named as 'Cactus Pump' is 177mm in length, 164mm in width, and 67mm in thickness including connectors and nuts. The weight and maximum cardiac output of Cactus Pump is 780g and 5L/min, respectively. The Cactus Pump that was developed as BVAD could be used as LVAD by attaching compliance caps on the 2 ports of one ventricle. The animal experiments were undergone 5 times for LVAD, and 6 times for BVAD. The best records were 28 days survival in both applications. There were 3 times of device failure and they were all associated with electrical connection and hermetic sealing. The KAH400 that has improved anatomical fitting characterisitcs and stroke volume is on development.

Three Cases of Waardenburg Syndrome Type 2 in a Korean Family

Joong Hyuk Choi,Sung-Kyun Moon,Ki Hwang Lee,Ho Min Lew,Yoon-Hee Chang 대한안과학회 2004 Korean Journal of Ophthalmology Vol.18 No.2

Waardenburg syndrome (WS) is a rare, autosomal dominant disorder characterized by sensorineural hearing loss, pigmentary disturbances of the skin, hair, and iris, and other developmental defects such as lateral displacement of both medial canthi and lacrimal puncta called dystopia canthorum. While mutations of the PAX3(paired box) gene have been identified in about 99% of WS type 1 cases, WS type 2 is a heterogeneous group, with about 15% of cases caused by mutations in microphthalmia associated transcription factor (MITF). We have experienced three cases of typical WS type 2 in a Korean family, for whom full ocular examination and genetic studies were performed. The genetic studies revealed no mutation in either PAX3 or MITF genes. The genetic basis, as yet unknown for most cases of WS type 2, might be found with further investigation.

Safety and Efficacy of Everolimus-Eluting Bioresorbable Vascular Scaffold Versus Second-Generation Drug-Eluting Stents in Real-World Practice

이주명,조현성,Choi Ki Hong,Hong David,박택규,Yang Jeong Hoon,송영빈,Choi Jin-Ho,Choi Seung-Hyuk,정진옥,이종영,Choi Young Jin,Chae Jei-Keon,허승호,Bae Jang-Whan,Oh Ju-Hyeon,전국진,Kim Hyun-Joong,조병렬,Shin Doosup,Lee Seung Hun 대한의학회 2023 Journal of Korean medical science Vol.38 No.5

Background: The risk of device thrombosis and device-oriented clinical outcomes with bioresorbable vascular scaffold (BVS) was reported to be significantly higher than with contemporary drug-eluting stents (DESs). However, optimal device implantation may improve clinical outcomes in patients receiving BVS. The current study evaluated mid-term safety and efficacy of Absorb BVS with meticulous device optimization under intravascular imaging guidance. Methods: The SMART-REWARD and PERSPECTIVE-PCI registries in Korea prospectively enrolled 390 patients with BVS and 675 patients with DES, respectively. The primary endpoint was target vessel failure (TVF) at 2 years and the secondary major endpoint was patientoriented composite outcome (POCO) at 2 years. Results: Patient-level pooled analysis evaluated 1,003 patients (377 patients with BVS and 626 patients with DES). Mean scaffold diameter per lesion was 3.24 ± 0.30 mm in BVS group. Most BVSs were implanted with pre-dilatation (90.9%), intravascular imaging guidance (74.9%), and post-dilatation (73.1%) at proximal to mid segment (81.9%) in target vessel. Patients treated with BVS showed comparable risks of 2-year TVF (2.9% vs. 3.7%, adjusted hazard ratio [HR], 1.283, 95% confidence interval [CI], 0.487–3.378, P = 0.615) and 2-year POCO (4.5% vs. 5.9%, adjusted HR, 1.413, 95% CI, 0.663–3.012, P = 0.370) than those with DES. The rate of 2-year definite or probable device thrombosis (0.3% vs. 0.5%, P = 0.424) was also similar. The sensitivity analyses consistently showed comparable risk of TVF and POCO between the 2 groups. Conclusion: With meticulous device optimization under imaging guidance and avoidance of implantation in small vessels, BVS showed comparable risks of 2-year TVF and device thrombosis with DES.

인공타액 조건에 따른 치과용 티타늄의 갈바니부식 특성

최창혁(Chang Hyuk Choi),이중배(Joong Bae Lee),최기열(Ki Yeol Choi) 대한치과재료학회 2009 대한치과재료학회지 Vol.36 No.1

Reduced pelvic field sparing anastomosis for postoperative radiotherapy in selected patients with mid–upper rectal cancer

Choi, Seo Hee,Chang, Jee Suk,Kim, Nam Kyu,Lim, Joon Seok,Min, Byung So,Hur, Hyuk,Shin, Sang Joon,Ahn, Joong Bae,Kim, Yong Bae,Koom, Woong Sub JAPAN RADIATION RESEACH SOCIETY 2017 JOURNAL OF RADIATION RESEARCH Vol.58 No.4

<P><B>Abstract</B></P><P>The aim of this study was to report the clinical results of reduced pelvic field radiotherapy (RT), excluding the anastomotic site, after total mesorectal excision in selected patients with rectal cancer. Between 2011 and 2014, 99 patients underwent upfront surgery for clinically less-advanced tumors but were finally diagnosed as pT3/N+. Among them, 50 patients with mid–upper rectal cancer who received postoperative RT with a reduced pelvic field were included in this retrospective review. This group was composed of patients with high seated tumors, complete resection with a clear circumferential resection margin, and no complication during surgery. We investigated treatment outcomes, toxicity and the effect of RT-field reduction on organs-at risk in 5 randomly selected patients. During the median follow-up period of 42 months (range: 15−59 months), tumors recurred in 9 patients (18%). The 3-year overall and disease-free survival were 98% and 81%, respectively. Distant metastasis was the dominant failure pattern (<I>n</I> = 8, 16%), while no recurrences occurred at or near anastomotic sites. No anastomotic complications were found on pelvic examination, images and/or colonoscopy. Reported acute and late RT-related toxicities were mostly mild to moderate, with only small numbers of Grade 3 toxicities. None of the patients developed Grade 4−5 acute or late toxicity. With a caudally reduced field, 64% reduction in absolute anastomotic exposure at the maximum dose was achieved compared with the traditional whole-pelvic field (<I>P</I> = 0.008). The reduced pelvic field RT was able to minimize late anastomotic complication without increasing its recurrence in selected patients with mid–upper rectal cancer in the postoperative setting.</P>

Comparison of Initial Weaning Success Rates and Weaning Periods between Synchronized Intermittent Mandatory Ventilation and Pressure Support Ventilation

Joong Hyuk Yang,Kyoung Min Lee,Hyun Kyung Lim,Dae Ja Um,Ryung Choi Korean Society of Critical Care Medicine 1997 Acute and Critical Care Vol.12 No.1

BACKGOUND: SIMV (synchronized intermittent mandatory ventilation) mode is comprised of a ventilator that intermittently enters the volume assist/control mode in conjunction with circuitry that allows for spontaneous ventilation by a demand flow system. There is additional work of breathing caused by the endotracheal tube and demand valve in SIMV. However, PSV (pressure support ventilation) has the ability to decrease work of breathing and to augment spontaneous breaths with a variable amount of inspiratory positive pressure with a clinician-selected level of inspiratory airway pressure. METHODS: To compare the initial weaning success rates and weaning periods between SIMV and PSV, we reviewed medical records of 103 intensive care unit patients, who had received mechanical ventilatory support and performed weaning. We compared the patients' characteristics, initial weaning success rates and ventilatory periods, weaning periods, weaning periods/ventilatory periods, ICU stays according to the weaning process (SIMV and PSV). And then we compared the same variables as the above between the initial weaning success group and initial weaning failure group. RESULTS: Patients' characteristics, ventilatory periods, weaning periods, ICU stays were similar, but there was significantly shorter weaning periods/ventilatory periods on PSV group. Initial weaning success rates according to the weaning process were similar. Ventilatory periods, weaning periods, weaning periods/ventilatory periods, ICU stays were significantly shorter on initial weaning success group. CONCLUSIONS: PSV could be used effectively as one of the weaning modes, and further studies are required about weaning criteria, weaning start time and weaning methods.

The Incidence and Risk Factors for Metachronous Gastric Cancer in the Remnant Stomach after Gastric Cancer Surgery

Choi Yonghoon,Kim Nayoung,Yoon Hyuk,Shin Cheol Min,Park Young Soo,Lee Dong Ho,Park Young Suk,Ahn Sang-Hoon,Suh Yun-Suhk,Park Do Joong,Kim Hyung Ho 거트앤리버 소화기연관학회협의회 2022 Gut and Liver Vol.16 No.3

Background/Aims: Less invasive surgical treatment is performed in East Asia to preserve postoperative digestive function and reduce complications such as postgastrectomy syndromes, but there is an issue of metachronous gastric cancer (GC) in the remaining stomach. This study aimed to analyze the incidence of metachronous GC and its risk factors in patients who had undergone partial gastrectomy. Methods: A total of 3,045 GC patients who had undergone curative gastric partial resection at Seoul National University Bundang Hospital were enrolled and analyzed retrospectively for risk factors, including age, sex, smoking, alcohol, Helicobacter pylori status, family history of GC, histological type, and surgical method. Results: Metachronous GC in the remaining stomach occurred in 35 of the 3,045 patients (1.1%): 23 in the distal gastrectomy group (18 with Billroth-I anastomosis, five with Billroth-II anastomosis), seven in the proximal gastrectomy (PG) group, and five in the pylorus-preserving gastrectomy (PPG) group. Univariate and multivariate Cox regression analyses showed that age ≥60 years (p=0.005) and surgical method used (PG or PPG, p<0.001) were related risk factors for metachronous GC, while male sex and intestinal type histology were potential risk factors. Conclusions: Metachronous GC was shown to be related to older age and the surgical method used (PG or PPG). Regular and careful follow-up with endoscopy should be performed in the case of gastric partial resection, especially in patients with male sex and intestinal type histology as well as those aged ≥60 years undergoing the PG or PPG surgical method.