A Comparative Experimental Study of the, In-vitro Efficiency of Hypertonic, Saline-Enhanced Hepatic Bipolar and, Monopolar Radiofrequency Ablation

Lee, Jeong Min,Han, Joon Koo,Kim, Se Hyung,Sohn, Kyu Li,Lee, Kyoung Ho,Ah, Su Kyung,Choi, Byung Ihn Korean Radiological Society 2003 Korean Journal of Radiology Vol.4 No.3

Low-intensity ultrasound increased colony forming unit-fibroblasts of mesenchymal stem cells during primary culture.

Choi, Woo Hee,Choi, Byung Hyune,Min, Byoung-Hyun,Park, So Ra Mary Ann Liebert, Inc 2011 Tissue engineering. Part C, Methods Vol.17 No.5

<P>Mesenchymal stem cells (MSCs) from bone marrow (BM) are an attractive cell source for stem cell-based therapeutic applications, but they exist at low-end ratios, which further decreases along with increased donor age. Thus, for clinical applications, there is a high demand for large numbers of active MSCs. This study investigated if low-intensity ultrasound (LIUS), a special type of mechanical stimulation, could increase the yield of MSCs during primary culture from the BM. Cultures were treated with LIUS for 10 min/day during the first 6 days after initial plating of BM mononuclear cells. After 12 days, the colony-forming unit-fibroblasts assay was performed, and the colonies were culture-expanded for further analyses. The LIUS stimulation showed a significant increase in the number of MSCs colonies when compared with that of the control group. The LIUS-stimulated MSCs showed no difference compared with the untreated control MSCs in terms of their proliferation rate, expression of MSCs-enriched surface antigens, and multi-lineage differentiation ability. The LIUS stimulation also showed an increase in the expression of integrins, fibronectin, and paxillin, and induced the formation of focal adhesions in MSCs, all of which involved in the cell adhesion process. These results demonstrated that LIUS stimulation could activate the cell adhesion process and increase the colony-forming ability of MSCs during the early stage of primary culture, without affecting their phenotypes and multi-potency. The results of this study suggest that LIUS could be a useful tool to obtain a large amount of MSCs for various therapeutic applications.</P>

Streptococcus salivarius의 요소분해효소 활성에 관한 연구

정상백,최호영,민병순,박상진,이진용,최기운 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

Dental caries is induced by organic acids produced by oral bacteria. In order to prevent dental caries, therefore, it is essential to maintain neutral pH in the oral cavity. Urea plays a major role in oral pH homeostasis. Urea is hydrolyzed by bacterial ureases to ammonia, causing a pH elevation, Streptococcus salivarius has been shown to be a major contribution to oral ureolysis. Synthesis of urease by S. salivarius appears to be constituitive, but can be greatly enhanced by low pH. It is, therefore, conceivable that ureolytic activity of S. salivarius from a carious lesion is greater than that of the bacterium from a healthy tooth. In the present study, urease activity of S. salivarius isolates from dental plaque of carious lesions was compared with that of the isolates from plaques of the teeth and the dorsum of the tongue; 45 S. salivarius strains were isolated from carious lesions(>C2) of 21 individuals with dental caries and 30 strains from 10 individuals without dental caries. The results were as follows: 1. All the 21 individuals with dental caries harbored ureolytic S. salivarius whereas 3 of 13 individuals without dental caries harbored non-ureolytic strains of S. salivarius. 2. All the 45 S. salivarius isolates from carious lesions showed urease activity. In contrast, of 30 isolates from individuals without dental caries, 17 isolates(56.7%) did not demonstrate urease activity, or if any, very little(<5μmol/min/mg). 3. Urease activity of the isolates from carious lesions was greater than that of the isolates from individuals without dental caries:the urease activity ranged from 42 to 381μmol/min/mg and from 0 to 208μmol/min/mg, respectively. 4. At acid pH(5.5), the isolates which showed intermediate urease activity at pH 7.0 demonstrated even higher activity whereas the isolate with no or lower urease activity did not show any significant difference in their activity. However, the isolates with the greatest urease activity from both individuals with and without dental caries, exhibited a rather much lower urease activity at pH 5.5. The overall results suggest that isolates may have their own urease activity but the isolates exposed to chronic acidic environment of the carious lesion might elevate urease activity of S. salivarius, which in turn, might influence on survival of S. salivarius itself and other bacteria establishing a new oral bacterial ecosystem.

Comparison of Dual Probe Bipolar Mode with Monopolar and Single Probe Bipolar Modes : Comparison of Dual Probe Bipolar Mode with Monopolar and Single Probe Bipolar Modes

Lee, Jeong Min,Han, Joon Koo,Kim,Se Hyung,Lee, Jae Young,Kim, Dae Jin,Lee, Min Woo,Cho, Gyung goo,Han, Chang Jin,Choi, Byung Ihn Korean Radiological Society 2004 Korean Journal of Radiology Vol.5 No.2

The effects of secondary task on the control of vehicle under driving simulator: a study among 50s taxi drivers

Han Soo Kim,Jin Seung Choi,Dong Won Kang,Hong Won Yeon,Mi Hyun Choi,Doo Hwan Ji,Byung Chan Min,Soon Cheol Chung,Gye Rae Tack 대한인간공학회 2011 대한인간공학회 학술대회논문집 Vol.2011 No.5

Objective: The aim of this study is to quantitatively evaluate the effects of the secondary task during simulated driving using the variable indicating control of vehicle. Background: There are so many researches for simulated driving and performance. For instance, some researches show that the effects of cell phone conversations on simulated driving. Cell phone conversations impaired explicit recognition memory. Method: Participants included 50s taxi drivers; 15 males and 15 females. All subjects were instructed to keep a distance (30m) from the car ahead and a constant speed (80km/hr or 100km/hr). Sending text message (STM) and Searching navigation (SN) were selected as the secondary task. Experiment consisted of rest for 3min., driving alone for 1min. and driving with secondary task for 1 min.. We were analyzed anterior-posterior coefficient of variation (APCV) and medial-lateral coefficient of variation (MLCV). Results: APCV was increased by 175.4% in STM and 223.8% in SN at 80km/hr. MLCV was increased by 242.3% in STM and 323.4% in SN at 100km/hr. There was no significant difference between genders. Conclusion: Consequently, performing secondary task during driving impaired the control of vehicle.

저산소성 허혈성 뇌손상을 유발시킨 어린 백서에서 Myeloperoxidase 측정 검사

양혜정(Hae Joung Yang),피대훈(Dae Hun Pee),임지혜(Ji Hye Lim),최병민(Byung Min Choi),이기형(Kee Hyoung Lee),은백린(Baik-Lin Eun) 대한소아신경학회 2002 대한소아신경학회지 Vol.10 No.2

목 적 : 예전에는 뇌경색 부위에서 발견되는 백혈구를 단지 뇌손상에 뒤따르는 생리적인 반응으로만 생각하였으나 최근 10년 사이 재관류 손상에서도 백혈구에 의한 염증 작용이 중요한 역할을 한다고 알려지면서 이들의 역할에 대한 연구가 새롭게 이루어지고 있다. PML의 존재는 세포질내 과립에서 분비되는 MPO를 생화학적으로 측정함으로서 증명할 수 있는데 저자들은 미성숙 뇌에서 저산소성 허혈증에 의한 뇌손상이 발생할 때 백혈구가 침윤되는 과정을 MPO 측정 검사를 통하여 관찰하였고, P와 L-selectin 억제제인 Fucoidin을 투여한 후 MPO의 변화를 확인하였다. 방 법 : 생후 7일된 어린 흰쥐를 사용하여 우측총 경동맥을 전기 응고시켜 자르고 8% 산소에 노출시켰다. 저산소 노출 후 회복 시간에 따라 동물을 희생시키고 뇌를 추출하여 뇌조직 1 g당 10mL의 20 mM potassium Phosphate buffer(pH 7.4)를 첨가하여 50초간 분쇄하였다. 각각의 균질회된 조직 샘플들은 4℃에서 20분 동안 원심 분리하여 상층액을 제거한 후, 침전물은 처음 조직량에 따라 조직 1 g당 10 mL의 0.5% cetylditrimethylethyl ammonium bromide(wt/vol)가 첨가된 50 mM potassium phosphate buffer(pH 6.0)를 첨가하였다. Vortex를 이용하여 buffer와 침전물을 잘 섞고 60℃수조에서 120분 동안 방치하였다. 그 후 각 조직 샘플들을 4 watts에서 음파처리하고 4℃에서 15분 동안 원심 분리를 시행하여 상층액을 새로운 tube에 옮겼다. MPO 측정검사를 위한 MPO reaction buffer는 50 mM potassium phosphate buffer(pH 6.0) 100 mL에 0.53 mM odianisidine edihydrochlorde와 0.0005% HO를 섞어 만들었다. MPO reaction solution 2.9 mL에 각각의 MPO sample 0.1 mL을 첨가하여 460 nm의 파장에서 5분 동안 MPO에 다른 흡광도 차이를 관찰하였다. 결 과 : 조직내 백혈구 침윤의 지표로 측정한 MPO 활성도는 대조군에서는 미미하였으나 총 경동백을 절단한 우측 대뇌군에서는 허혈 및 저산소증 유발 후 8시간째부터 현저히 증가되기 시작하여 24시간 경과 후 발현이 가장 높았으며, Fucoidin 50 mg/kg으로 전처치한 약물 실험군에서는 MPO 활성도가 현저히 감소하였다. 결 론 : 백혈구는 미성숙 뇌의 저산소성 허혈증에 의한 뇌손상에서 중요한 매개체 역할을 하며, 백혈구의 생화학적 활성도를 나타내는 MPO 활성도는 저산소성 허혈성 뇌손상의 정도를 측정하는 지표로 이용될 수 있다고 생각된다. Purpose : Neutrophils found around an infarcted area in the brain was once considered as only the physiologic response following the brain injury, but recent studies have shown that inflammatory responses by neutrophils play an important role in the reperfusion injury. The presence of ploymorphonuclear leukocytes(PML) is proven by biochemical assay of myeloperoxidase(MPO) Secreted in the cytoplasmic granules. We observed the process of PML infiltration on hypoxic-ischemic brain injury of immature rats by the assay of MPO activity and changes of the MPO activity after the administration of fucoidin, inhibitor of P- and L-selectin. Methods : We used a well characterized model of the brains of 7 day-old-rats, which had unilateral hypoxic and ischemic injuries(HI). Those injuries were induced by unilateral carotid artery ligation followed by timed exposure to hypoxic inspiratory gas mixture(8% O). MPO activity was measured in the brain tissue homogenates of HI rats(n=18) at 0, 2, 8, 24 and 48 hrs and in rats that received fucoidin immediately before and again after hypoxia(50 mg/kg, n=6) at 8 and 24 hrs. Controls(n=2) were rats with neither hypoxia nor ischemia. The brain samples were homogenized in 20 mM potassium phosphate buffer(pH 7.4) for 50 secs. The homogenate was centrifuged at 14,000 g at 4℃ for 15 mins and the supernatant was discarded. The tissue was pulverized, weighed, and suspended in 1 mL of 50 mM potassium phosphate buffer solution(pH 6.0) contatining 0.5% cetylditrimethylammonium bromide(wt/vol). The tissue was sonicated and centrifuged at 10,000 g for 15 mins. 200 µL of the supernatant was mixed with 1 mL of 50 mM potassium phosphate buffer solution(pH 6.0) containing 10 μL of 1.325 mM o-dianisidine hydrochloride and 170 µL of 3% hydrogen peroxide(vol/vol). Changes in absorbance at 460 nm were measured for 5 mins by using microplate reader. One unit of MPO activity was defined as that degrading 1 µmol peroxide/min at 25℃, and the result was expressed as units of MPO/100 gm tissue. Results : In HI rats, MPO activity increased at 2 hrs after HI and peaked at 24 hrs in the right hemisphere. In rats with fucoidin treatment immediately before and again after hypoxia, the MPO activity significantly decreased in both hemispheres compared with HI rats(P<0.05). MPO activity in the tissue of control rats was insignificant. Conclusion : The dynamic changes of the MPO activity suggest the important role of PMN on hypoxic-ischemic brain injuries in immature rats. MPO activity could be used as an index of the severity of injuries of hypoxic-ischemic brains.

Sustained-release praziquantel tablet : pharmacokinetics and the treatment of clonorchiasis in beagle dogs

Hong, Sung-Tae,Lee, Sang Hyup,Lee, Seung-Jin,Kho, Weon-Gyu,Lee, Mejeong,Li, Shunyu,Chung, Byung-Suk,Seo, Min,Choi, Min-Ho 梨花女子大學校 藥學硏究所 2003 藥學硏究論文集 Vol.- No.12

Praziquantel is rapidly absorbed and secreted; and thus fractional doses are recommended for the treatment of cestode and trematode infections. In the present study, we developed a new praziquantel tablet formula allowing sustained-release (SRP). In vitro dissolution of SRP tablets showed that praziquantel at 300 ㎎/tablet combined with hydroxypropyl methylcellulose dissolved completely at a constant rate over 10 h, whereas the conventional praziquantel tablet (PZQ) was only 40% dissolved. Pharmacokinetic studies in dogs confirmed that SRP was absorbed more slowly than PZQ. The mean value of the area under the concentration/time curve from 0 h to the final observation time, the maximum concentration in serum, and the time of maximum concentration in serum for SRP were 3.471.500 ng/min for 0.25 ㎖, 10,300 ng for 0.25 ㎖, and 192 min. while the values for PZQ were 688,600 ng/min for 0.25㎖, 2,500 ng for 0.25㎖, and 135 min. The cure rate in dogs with a heavy infection (500 metacercariae) treated with a single dose of SRP (150 ㎎/tablet) at 50 ㎎/㎏ was 80%, while in dogs treated with a single dose of SRP (300 ㎎/tablet) at 30 mg/kg it was 60%, and the cure rate with PZQ was 20%. In each case. the egg reduction rate was similar (over 90%). No abnormal liver functions or hepatic or renal pathologies were observed in dogs administered with SRP at 30 ㎎/㎏. The SRP tablet showed sustained release and slow absorption; and it had an improved anthelmintic efficacy against Clonorchis sinensis in experimental dogs. compared with conventional praziquantel.

순수티타늄 용접재의 피로크랙 진전거동에 관한 연구

최병기,국중민,장경천,권택용 朝鮮大學校 機械技術硏究所 2001 機械技術硏究 Vol.4 No.1

본 연구에서는 원자력 발전소의 터빈장치에 사용되는 순수티타늄 용접재의 피로수명과 크랙성장속도 등을 열영향부, 용접부 그리고 모재부를 각각 비교하기 위하여 시험편을 크게 용접된 4개의 시험편(Specimen1∼4 ; 초기노치에서 2∼3mm 떨어진 부분이 각각 H.A.Z, 본드부, 용접부, 모재부 등에 위치함)과 모재 시험편으로 나누어 피로시험을 수행한 결과 다음과 같은 결론을 얻을 수 있었다. 1) 순수티타늄 용접재 중 Specimen-2가 모재 시험편에 비해 피로수명이 약 700%로 가장 크게 나타났다. 2) 초기 크랙이 1mm로 성장하는데 걸리는 평균 크랙진전속도를 조사한 결과 Specimen-2가 모재에 비하여 약 30배로 가장 낮은 크랙진전속도를 나타내고 있었으며, 초기 크랙진전속도가 최종 파단 수명에 매우 큰 영향을 미치고 있음을 알 수 있었다. 3) 시험편 중 피로수명이 가장 큰 Specimen-2 시험편은 노치 선단으로부터 H.A.Z까지 거리가 약 6.7mm로 전체 파단길이의 약 25%를 차지하고 있었다. 4) da/dN과 ΔK를 고찰한 결과 용접으로 인해 생긴 두 개의 기울기로 인하여 Paris 법칙에 적용하기에는 부적당함을 알 수 있었다. In this study, Specimens were classified four welded specimens and a base metal to investigate fatigue life and crack growth rate of pure titanium welding materials, and Ti was used in turbine equipment of nuclear power generation, etc. The summarized results are as follows ; 1) Specimen-2 was bigger 712% than base metal, when it was compared with other welding materials. 2) As the result of specimens data. Specimen-2 crack Behavior rate was lower 30 times than base metal, and so total fracture life was very influenced by it 3) Notch tip of Specimen-2 was offsetted 6.7mm from boundary H.A.Z, and it formed 25% in total fracture length. 4) As the considering of da/dN and ΔK, Paris' law is incongruous in this study, because two inclines were on one date.

離岸堤에 의한 海雲臺海濱의 浸蟲防止에 관한 實驗的 硏究

閔丙亨,崔道碩,閔一圭,李東明 東亞大學校 海洋資源硏究所 1989 硏究論文集 Vol.2 No.1

A three-dimensional hydraulic model test was accomplished to study nourishment effects on the lengths, apperture width of offshore breakwaters and the site where they are to be built when they were adopted as an erosion protection method in HAEUNDAE beach which is showing obvious erosion phenomena. The experimental results showed that the nourishment effects can be maximized when the length and aperture width of offshore breakwaters are 200m, 100m, respectively, and the water depth at which they are located is about 3m.

자외선 살균효과에 미치는 옥수(玉水)와 옥분말(玉粉末)의 영향

최영길,민병례 한양대학교 자연과학연구소 2001 自然科學論文集 Vol.20 No.-

생체에 대한 옥수와 옥분말의 자외선 차단효과를 알아보기 위하여 동물의 피부 생태계와 연관있는 미생물들(Gram+, Gram-, 및 Eucaryotic yeast)을 대상으로 실험한 결과 다음과 같은 결과를 얻었다. 1.자외선 조사후 생존한 미생물 개체수의 측정결과로 분석해 볼 때 옥수첨가 액체배지에서 보다 옥분말 첨가 액체배지에서 자외선 차단효과가 높게 나타났다. 2.자외선 차단효과는 Escherichia coli, Saccharomyces cerevisiae, Bacillus subtilis의 배양체의 순으로 확인되었다. This experiment was designed to elucidate the effect of jade product (jade powder and jade water) on the sterilization by ultraviolet ray as the ecological model of animal skin. The microorganisms(Gram+, Gram-, and Eucaryote) which are closely related to animal skin were cultured in broth medium with jade powder and jade water, illuminated by ultraviolet ray to count viable number of microorganism, and evaluated the effect of jade product on the strength of ultraviolet ray. The results of this experiment are summarized as the followings. 1.The survival number of microbes illuminated by UV light were higher in the cultures of jade powder than those in the jade water, It could be evaluated that jade powder has an effect to interrupt the sterilization of UV light. 2.The sterilization by ultraviolet ray was decreased in order of the cultures as the Escherichia coli, Saccharomyces cerevisiae, and Bacillus subtilis.