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이진호,최선웅,강길선,노승무,민병무,김용백,김학용 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1
"Biomaterials" are nonviable materials used in medical devices, intended to interact with biological systems. They should have "biocompativility", which is defined as the ability of materials to perform with an appropriate host response in a specific application. It includes many materials that are often classified as biomaterials. Metals, ceramics, polymers, glasses, carbons, and composite materials are some examples. Among them, biodegradable polymers are discussed in this revies article. Since a biodegradable polymeric implant does not have to be removed surgically once it is no longer needed, biodegradable polymers are of value in short-term applications that require only the temporary presence of a polymeric implant. Main short-term medical applications of biodegradable polymers include the temporary tissue scaffold, the temporary adhesion barrier, the drug delivery device, and the multifunctional implant. In this article, the properties, processing methods, and medical applications of the biodegradable polymers are reviewed.
( Woong Gil Choi ),( Gi Chang Kim ),( Cheol Ho Lee ),( Hye Young Kim ),( Dong Woon Kim ) 대한내과학회 2021 The Korean Journal of Internal Medicine Vol.36 No.2
Background/Aims: Coronary endothelial and microvascular function play important roles in cardiovascular disease. We aimed to evaluate the effect of ticagrelor on coronary artery function and tested the antiplatelet effect of low dose ticagrelor in East-Asian patients. Methods: Sixty-one consecutive patients with non-significant coronary disease were included in the study. Initially, patients were randomized in 1:1:1 ratio to receive drugs: ticagrelor 90 mg twice a day (bid; n = 22), ticagrelor 45 mg bid (n = 19) or clopidogrel 75 mg once a day (qd; n = 20) and then divided into two groups (ticagrelor vs clopidogrel) for evaluation of coronary artery function, and three groups for evaluation of antiplatelet function. Endothelial dysfunction was measured by coronary flow reserve (CFR), and changes in the levels of asymmetric dimethylarginine (ADMA), cluster of differentiation (CD) 40 ligand, and P-selectin. Microvascular function was evaluated as index of microvascular resistance (IMR). Platelet reactivity was assessed by VerifyNow P2Y12 assay. Results: The levels of CFR, ADMA, and CD 40 ligand were not different between the two groups. However, P-selectin was lower in the ticagrelor group compared with clopidogrel group. IMR was significantly lower in the ticagrelor group compared with clopidogrel group (median, 15.0 [interquartile range, 12.0 to 21.0] vs. 47.5 [23.0 to 67.5], p = 0.014). There was significant difference in platelet inhibition among the three groups (ticagrelor 90 mg bid vs. ticagrelor 45 mg bid vs. clopidogrel 75 mg qd; 85.57 ± 47.63 vs. 120.33 ± 51.09 vs. 256.42 ± 55.10, p < 0.001) Conclusions: It is hypothesized that ticagrelor might ameliorate the coronary microvascular function. When compared with clopidogrel, low dose ticagrelor exhibited satisfactory antiplatelet effect in the present study.
( Woong Gil Choi ),( Soo Hyun Kim ),( Hyung Seok Yoon ),( Eun Joo Lee ),( Dong Woon Kim ) 대한내과학회 2015 The Korean Journal of Internal Medicine Vol.30 No.1
Background/Aims: Although drug-eluting stents (DESs) effectively reduce restenosis following percutaneous coronary intervention (PCI), they also delay re-endothelialization and impair microvascular function, resulting in adverse clinical outcomes. Endothelial progenitor cell (EPC) capturing stents, by providing a functional endothelial layer on the stent, have beneficial effects on microvascular function. However, data on coronary microvascular function in patients with EPC stents versus DESs are lacking. Methods: Seventy-four patients who previously underwent PCI were enrolled in this study. Microvascular function was evaluated 6 months after PCI based on the index of microvascular resistance (IMR) and the coronary flow reserve (CFR). IMR was calculated as the ratio of the mean distal coronary pressure at maximal hyperemia to the inverse of the hyperemic mean transit time (hTmn). The CFR was calculated by dividing the hTmn by the baseline mean transit time. Results: Twenty-one patients (age, 67.2 ± 9.6 years; male:female, 15:6) with an EPC stent and 53 patients (age, 61.5 ± 14.7 years; male:female, 40:13) with second-generation DESs were included in the study. There were no significant differences in the baseline clinical and angiographic characteristics of the two groups. Angiography performed 6 months postoperatively did not show significant differences in their CFR values. However, patients with the EPC stent had a significantly lower IMR than patients with second-generation DESs (median, 25.5 [interquartile range, 12.85 to 28.18] vs. 29.0 [interquartile range, 15.42 to 39.23]; p = 0.043). Conclusions: Microvascular dysfunction was signif icantly improved after 6 months in patients with EPC stents compared to those with DESs. The complete re-endothelialization achieved with the EPC stent may provide clinical benefits over DESs, especially in patients with microvascular dysfunction.
도축 한우의 복강내 지방괴사증 발생과 병리조직학적 연구
최길성 ( Gil Seong Choi ),임채웅 ( Chae Woong Lim ),채효석 ( Hyo Seok Chai ),최인열 ( In Yeol Choi ),이성효 ( Sung Hyo Lee ),김추철 ( Chu Cheul Kim ),서문정 ( Moon Jeong Suh ) 한국동물위생학회 1998 한국동물위생학회지 (KOJVS) Vol.21 No.1
The bovine fat necrosis is often seen as an incidental lesion in the adipose tissues of the abdominal cavity. Most of affected animals, however, have been detected at the slaughter house or routine necropsy. The purpose of this study was to examine the occurrence and distribution of abdominal fat necrosis in Korean native cattle, and its pathologic features. Postmortem inspection at an Chonju abattoir during a three-month period in 1997 detected at necrosis lesions in 67(6.6%) of the 1,012 animals received for slaughter. The occurrence was mainly in alimentary tracts and perirenal. Both sexes were affected, but the lesions were predominantly occurred in female. Gross lesions were white or yellowish in color and formed hard lumps irregular in shape ranging from small nodules to large solid masses. On the cut surface, lesions were occasionally seen chalky calcified granules and some of the lesions contained oil-like fluid. The surface of irregular shaped masses constricted kidneys and intestinal loops. Microscopically, the masses were encapsulated by thickened fibrous tissue, which infiltrated deeply and divided them into many irregular lobules. Initial lesions presented mild inflammatory cell and fibrous proliferation. It became fibroplasia in progressive lesions and resembled chronic lesion, eventhough no grossly apparent inflammatory reaction. The hard consistency of masses, due to fibroplasia, can compress the intestines, urinary organs, and reproductive organs.
급성 심근 경색 환자에서 재관류 방법에 따른 P파폭과 P파 분산의 변화
최웅길 ( Woong Gil Choi ),김대혁 ( Dae Hyeok Kim ),김기창 ( Gi Chang Kim ),안인선 ( In Sun Ahn ),김수현 ( Soo Hyun Kim ),유형권 ( Hyung Kwon Yu ),권준 ( Jun Kwan ),박금수 ( Keum Soo Park ),이우형 ( Woo Hyung Lee ) 대한내과학회 2007 대한내과학회지 Vol.73 No.5
Background: P wave dispersion (PWD) and P wave duration have been used to evaluate the discontinuous propagation of sinus impulse and the prolongation of atrial conduction time, respectively. This study was conducted to compare the change of the maximal P wave duration (Pmax) and PWD according to the treatment strategy used in patients with an acute myocardial infarction (AMI). Methods: We retrospectively evaluated 86 patients that experienced an AMI. Patients were classified into three groups according to the treatment strategy: primary percutaneous coronary intervention (PCI), thrombolytic therapy, and delayed PCI. ECGs that were obtained from all patients on admission and on the second day were analyzed. The Pmax and minimum P wave duration (Pmin) were measured from a 12-lead ECG. The PWD was calculated as the difference between the Pmax and Pmin. Result: There was no significant difference in the age, gender, medication, coronary risk factor, ejection fraction, left atrial diameter, basal Pmax and PWD among the groups. However, there were significant differences in P max and PWD between the primary PCI group and the other groups on the second day after hospital admission. In the thrombolytic therapy and delayed PCI groups, the PWD was significantly lower in the patients with a patent infarct-related artery (IRA) than in patients without a patent IRA on the second day after hospital admission. Conclusions: These findings suggest that a primary PCI decreased the Pmax and PWD more than thrombolytic therapy or a delayed PCI.(Korean J Med 73:489-495, 2007)
전신성 홍반성 루푸스 환자에서 면역 억제 요법 후 발생한 카포시 육종
최웅길 ( Woong Gil Choi ),김준미 ( Joon Mee Kim ),권성렬 ( Seong Ryul Kwon ),이문희 ( Moon Hei Lee ),이진수 ( Jin Soo Lee ),박원 ( Won Park ) 대한류마티스학회 2006 대한류마티스학회지 Vol.13 No.1
A 41-year-old woman was admitted because of dyspnea on exertion for one month. She was diagnosed to have systemic lupus erythematosus 4 years ago and has taken prednisolone and azathioprine. One month prior to admission she visited dental clinic for painful gingival swelling and gingival biopsy was performed. Physical examination showed multiple round elevated purpuric rashes in thoracic wall. Gingiva and skin biopsy showed Kaposi`s sarcoma. Computed tomography of abdomen and chest revealed ill-defined nodules in both lung fields and multiple small para-aortic lymphadenopathies. Chemotherapy with paclitaxel was given for Kaposi`s sarcoma. Prednisolone was tapered. After the 7th course of chemotherapy, the lesions show marked improvement in size and number.
Impact of Cigarette Smoking: a 3-Year Clinical Outcome of Vasospastic Angina Patients
Byoung Geol Choi,Seung-Woon Rha,Taeshik Park,Se Yeon Choi,Jae Kyeong Byun,Min Suk Shim,Shaopeng Xu,Hu Li,Sang-Ho Park,Ji Young Park,Woong Gil Choi,Yun-Hyeong Cho,이선기,Jin Oh Na,Cheol Ung Choi,Hong Euy 대한심장학회 2016 Korean Circulation Journal Vol.46 No.5
However, it is largely unknown whether smoking adds to any long-term clinical risk in VSA patients. Subjects and Methods: A total of 2797 patients without significant CAD underwent acetylcholine (Ach) provocation test between November 2004 and October 2010. Patients were divided into three groups, based on the presence of coronary artery spasm (CAS) and smoking habits (non-CAS group: n=1188, non-smoking CAS group: n=1214, smoking CAS group: n=395). All CAS patients were prescribed with anti-anginal medications for at least 6 months. The incidence of major clinical outcomes and recurrent angina of these groups were compared up to 3 years. Results: There were considerable differences in the baseline clinical and angiographic characteristics among the three groups, but there was no difference in the endpoints among the three groups (including individual and composite hard endpoints) such as death, myocardial infarction, de novo percutaneous coronary intervention, cerebrovascular accident, and major adverse cardiac events. However, there was a higher incidence of recurrent angina in both the non-smoking CAS group and smoking CAS group, as compared to the nonCAS group. In multivariable adjusted Cox-proportional hazards regression analysis, smoking CAS group exhibited a higher incidence of recurrent angina compared with the non-CAS group (hazard ratio [HR]; 2.46, 95% confidence interval [CI]; 1.46-4.14, p=0.001) and nonsmoking CAS group (HR; 1.76, 95% CI; 1.08-2.87, p=0.021). Conclusion: Cigarette smoking CAS group exhibited higher incidence of recurrent angina during the 3-year clinical follow-up compared with both the non-CAS group and non-smoking CAS group. Quitting of smoking, paired with intensive medical therapy and close clinical follow-up, can help to prevent recurrent angina.
Woong-Chul Shin,Kyu-Jeong Choi,Soon-Gil Yoon 한국진공학회(ASCT) 2000 Journal of Korean Vacuum Science & Technology Vol.4 No.1
Ferroelectric YMnO₃ thin films were deposited on Y₂O₃/Si(100) substrates by metalorganic chemical vapor deposition. The YMnO₃ thin films annealed in vacuum ambient (100 mTorr) above 750℃ show hexagonal structured YMnO₃. However, the film annealed in oxygen ambient shows poor crystallinity, and the second phase as Y₂O₃ and orthorhombic-YMnO₃ were shown. The C-V characteristics have a hysteresis curve with a clockwise rotation, which indicates ferroelectric polarization switching behavior. When the gate voltage sweeps from +5 to 5 V, the memory window of the Pt/YMnO₃/Y₂O₃/Si gate capacitor annealed at 850℃ is 1.8 V. The typical leakage current densities of the films annealed in oxygen and vacuum ambient are about 10^(-3) and 10^(-7) A/㎠ at applied voltage of 5 V.