Prevotella nigrescens의 용혈특성에 관한 연구

곽주석,장훈상,장석우,이수종,유용욱,민경산 大韓齒科保存學會 2005 Restorative Dentistry & Endodontics Vol.30 No.4

세균의 용혈활성은 세균이 숙주 내에서 생존하기 위해 필요한 철을 획득하기위한 특성이며 기능면에서 볼 때 숙주에 대한 중요한 독력인자로 간주될 수 있다. 본 연구에서는 괴사치수 및 치근단 치주염으로 진단된 환자의 근관에서 분리한 Prevotella nigrescens의 용혈활성을 다양한 조건 하에서 측정하여 그 특성을 규명하는 것을 목적으로 한다. 1. 임상에서 분리한 P. nigrescers와 표준균주인 P. nigrescers ATCC 33563에서 모두 용혈활성이 나타났다. 2. 사람, 면양 및 말 세 가지 종에 대해 용혈활성을 비교한 결과 사람의 적혈구에서 가장 강한 용혈활성을 나타내었다. 3. 용혈소 억제제인 NaN₃와 dithiothreitol (DTT)는 농도의존적으로 P.nigrescers의 용혈활성을 감소시켰다 (p<0.05). 4. P. nigrescers가 최대 용혈활성을 나타내는 최적의 pH는 4이었으며, 50℃이하의 온도에서는 용혈활성을 보였으나 95℃에서 급격히 감소하였다. 5.배양조건에 따른 P. nigrescens의 용혈활성을비교한 결과 10% CO₂배양기에 배양한 경우혐기성 조건에서 배양한 것보다 더 높은 용혈활성을 보였다. Hemolytic property is a specific feature of bacteria to obtain iron which is essential for its survival in host tissues. Therefore, it is thought to be one of several factors of virulence. The purpose of this study was to investigate the hemolytic properties of Prevotella nigrescens isolated from the teeth diagnosed as pulp necrosis and apical periodontitis under the presence of hemolysin inhibitors such as NaN3 and dithiothreitol, heat, various pH and cultural conditions. The results were as follows; 1. Clinically isolated P. nigrescens strains and standard P. nigrscens ATCC 33563 showed hemolytic activity. 2. P. nigrescens showed higher hemolytic activity against human erythrocytes than sheep or horse erythrocytes. 3. NaN₃ and dithiothreitol (DTT) reduced the hemolytic activity of P. nigrescens in a dose dependent manner (p<0.05). 4. Optimal pH for the maximum hemolytic activity of P. nigrescens was 4.0 and the hemolysin was stable under the 50℃, but the hemolytic activity was significantly decreased at 95℃. 5. P. nigrescens cultured in 10% CO₂ condition showed higher hemolytic activity than the bacteria cultured in the anaerobic condition.[J Kor Acad Cons Dent 30(4):335-343,2005]

지혈제 오염이 콤포머의 전단결합강도에 미치는 영향

허정무,곽주석,이황,이수종,임미경 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.2

One of this latest concepts in bonding are "total etch", in which both enamel and dentin are etched with an acid to remove the smear layers, and "wet dentin" in which the dentin is not dry but left moist before application of the bonding primer. Ideally, the application of a bonding agent to tooth structure should be insensitive to minor contamination from oral fluids. Clinically, contaminations such as saliva, gingival fluid, blood and handpiece lubricant are often encountered by dentists during cavity preparation. The aim of this study was to evaluate the effect of contamination by hemostatic agents on shear bond strength of compomer restorations. One hundred and ten extracted human maxillary and mandibular molar teeth were collected. The teeth were removed soft tissue remnant and debris and stored in physiologic solution until they were used. Small flat area on dentin of the buccal surface were wet ground serially with 400, 800 and 1200 abrasive papers on automatic polishing machine. The teeth were randomly divided into 11 groups. Each group was conditioned as follows: Group 1: Dentin surface was not etched and not contaminated by hemostatic agents. Group 2: Dentin surface was not etched but was contaminated by Astringedent® (Ultradent product Inc., Utah, U.S.A.). Group 3: Dentin surface was not etched but was contaminated by Bosmin®(Jeil Pharm, Korea).). Group 4: Dentin surface was not etched but was contaminated by Epri-dent®(Epr Industries, NJ, U.S.A.). Group 5: Dentin surface was etched and not contaminated by hemostatic agents. Group 6: Dentin surface was etched had contaminated by Astringedent®. Group 7: Dentin surface was etched and contaminated by Bosmin®. Group 8: Dentin surface was etched and contaminated by Epri-dent®. Group 9: Dentin surface was contaminated by Astringedent®. The contaminated surface was rinsed by water and dried by compressed air. Group 10: Dentin surface was contaminated by Bosmin®. The contaminated surface was rinsed by water and dried by compressed air. Group 11: Dentin surface was contaminated by Epri-dent®. The contaminated surface was rinsed by water and dried by compressed air. After surface conditioning. F2000® was applicated on the conditoned dentin surface. The teeth thermocycled in distilled water at 5℃ and 55℃ for 1,000 cycles. The samples were placed on the binder with the bonded compomer-dentin interface paralled to the knife-edge shearing rod of the Universal Testing Machine(Zwick Z020, Zwick Co., Germany) running at a cross head speed of 1.0mm/min. Group 2 showed significant decrease in shear bond strength compared with group 1 and group 6 showed significant decrease in shear bond strength compared with group 5. There were no significant differences in shear bond strength between group 5 and group 9, 10 and 11.

감염근관에서 Black-Pigmented Bacteria의 동정에 대한 연구

권은경,김은숙,곽주석,이황,이수종,임미경 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.1

Black-pigmented bacteria have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonass endodontalis, Porphyromonas gingicalis, Prevotella intermedia, and Prevotella nigresceus. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections. The aim of this study was to identify P.endodontalis, P.gingivalis, P.intermedia, and P.nigrescens by using special potency disk test, filter paper spot test, 16S rRNA gene-directed PCR, and API 32A. Microbial samples were collected from root canals of 33 intact teeth with necrotic pulp and/or apical periodontitis. Conventional laboratory methods were used for identification of the strains of black pigmented bacteria. Eighteen of 33 samples were positive for the growth of black-pigmented bacteria. Five colonies were cultured from each pure cultured colonies from Brucella agar plate. Seventy seven colonies were positive for the growth of black-pigmented bacteria. Thirty three of 77(42.6%) were identifed as P.nigrescens, 10 of 77(12.9%) were P.gingivalis, 6 of 77(7.8%) were P.endodontalis, 10 of 77(12.9%) were P.intermedia. On the contraty the reference strains of P.nigrescens, experimental strains of P.nigrescens was sensitive to kanamycin in special potency disk test. 16S rRNA gene PCR and API test after rapid presumptative identification methods. such as special potency disk test and filter paper spot test, would be accurate detection methods for black-pigmented bacteria.

크릴분말이 콜레스테롤 및 카드뮴 식이 흰쥐의 간 및 심장 지질에 미치는 영향

조영숙,박석규,박정로,손미예,문주석,곽수동 순천대학교 기초과학연구소 1992 基礎科學硏究誌 Vol.3 No.-

In order to investigate effects of krill on lipid components of liver and heart in cholesterol and cadmium-fed rats, male Sprague-Dawley rats were raised for 4 weeks with 8 experimental diets. Krill used in this experiment contained 65.4%(w/w) of protein and 16.7% of lipid. Krill contained 35% of polyunsaturated fatty acids and more unsaturated fatty acids than saturated fatty acids by 2 times. Amino acid content of krill was high in order of Glu, Asp, Tyr and Lys. Rats fed krill diet showed more food intake and weight gain compared with control group. However, food efficiency ratio and weight of liver and heart were not significantly different. The ingestion of cadmium resulted in a severe restriction in growth rate with normal or mild reduction of liver and heart weight. Cadmium also caused a significant decrease in food efficiency ratio. The contents of total and free cholesterol of liver and heart in rats fed krill diets were similar or slightly higher than those fed control diet. Dietary krill also showed no significant difference in liver and heart cholesterol levels in rats with cadmium ingestion. The contents of phospholipid and triglyceride in liver and heart of krill group were slightly higher than those of control group. Supplement of krill reduced triglyceride content of liver in rats ingested with cadmium without any effect on the level of phospholipid and heart lipids. The concentration of cadmium in plasma significantly increased with dietary krill. However, the krill supplement did not influence the concentration of cadmium in liver or heart. A significant accumulation of lipid in liver tissue was observed in all dietary groups but standard group. However, no difference in degree of lipid accumulation was found among the dietary groups. Necrosis and hemolysis of liver in all dietary groups were not shown.