소아의 치면세균막에 존재하는 mutans streptococci의 분포

국중기,박종휘,유소영,김화숙,이난영 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.3

한국인 소아의 치면세균막에 존재하는 mutans streptococci 종 및 생물형의 발현빈도와 치아우식경험지수와 상관관계를 알아보기 위하여. 조선대학교 치과병원에 내원한 12세 미만 113명의 소아 환자의 치아우식경험지수를 구하고, 이들의 상하악 유전치 및 유구치의 협면 및 설면의 치면세균막 샘플을 채취하여 mutans streptococci를 mitis-salivarius bacitracin 배지에서 선택적으로 분리하였다. 이들의 biotype을 알아보기 위해 생화학적 검사를 실하였고, 이들의 종 수준에서의 동정을 위해 dextranase 유전자를 표적으로 하는 중합효소연쇄반응을 시행하여 하였다. 113명의 환자 중에서 40명의 치면세균막에서 40 균주의 mutans streptococci이 검출되었다. 이들 중 생물형 제 Ⅰ형 (45%)이 가장 많이 검출되었으며, 그 다음으로 제Ⅳ형 (32.5%), 제 Ⅱ형 (15%). 제 Ⅴ형 (5%), 제 Ⅲ형 (2.5%) 순으로 검출되었다. 또한, 종 수준에서의 발현빈도를 알아본 결과 S. mutans가 69%, S. sobrinus는 31%였다. Mutans streptococci 종 또는 생물형에 따른 환자의 치아우식경험지수간의 차이는 없는 것으로 조사되었다(p>0.05). 이상의 결과를 종합할 때, 한국인의 소아의 구강 내에 존재하는 mutans streptococci중 생물형 제 Ⅰ형인 S. mutans가 가장 높은 빈도로 존재하며, 치아우식증이 세균학적 요소만이 아닌 기타 여러원인 요소에 의해 발병되는 다는 여러 연구 결과와 일치함을 알 수 있었다. The aim of this study is to survey the frequency of mutans streptococci species and biotypes isolated from dental plaque in Korean children and the relationship between species and biotypes of mutans streptococci and dft index. Dental plaques were collected from the anterior and molar teeth of upper and lower jaws in the subjects, aged below 12 years old. A dental examination was performed for dft (decayed, filed, total) with the WHO caries diagnostic criteria. The mutans streptococci from the sample were cultured selectively on mitis salivarius-bacitracine (MSB) agar plate. For biotyping of mutans streptococci, biochemical test was performed. From the culture, bacterial genomic DNA was prepared f3r using of PCR template for the identification of mutans streptococci at the species-level. Forty strains of mutans streptococci were isolated from dental plagues of 40 patients. The biotype Ⅰ (45%) and biotype Ⅳ (32.5%) were most frequently detected. The prevalence of s. mutans and S. sobrinus was 69% and 31%, respectively There was no positive relationship between species and biotypes of mutans streptococci and dft index. Our results revealed that biotype Ⅰ and S. mutans were frequently detected in Korean children and support that dental caries incidents by many causative factors not only bacterial factor.

치면세균막에서 분리한 뮤탄스 연쇄상구균 및 Streptococcus anginosus의 수종 항생제에 대한 감수성 조사

국중기,임상수,유소영,황호길 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.5

The aim of this study was to investigate the susceptibility of mutans streptococci (S. mutans and S. sobrinus) and Streptococcus anginosus, for seven antibiotics, penicillin G, amoxicillin, ciprofloxacin, cefuroxime, erythromycin, bacitracin, and vancomycin. The minimum inhibitory concentration (MIC) of seven antibiotics against 3 species (type strains) of mutans streptococci and S. anginosus, 10 strains (wild type) of S. mutans, 7 strains (wild type) of S. sobrinus, and 11 strains (wild type) of S. anginosus, were measured by broth dilution method. All of the type strains of mutans streptococci and S. anginosus had the same susceptibility for penicillin G, amoxicillin, cefuroxime and bacitracin. Type strain of S. anginosus was sensitive in ciprofloxacin, but those of mutans streptococci were not. All of the clinical isolates of mutans streptococci and S. anginosus had the same susceptibility for the seven antibiotics. Our data reveal that mutans streptococci and S. anginosus have similar antibiotic-resistant character. In addition. these results may offer the basic data to verify the antibiotic-resistant mechanism of mutans streptococci and S. anginosus.

Bifidobacterium angulatum으로부터 α-galactosidase의 정제 및 특성

강대중,민해기,강국희 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

α-galactosidase는 (α-D-galactoside galactohydrolase: EC 3.2.1.22)는 다당류나 올리고당인 melibiose, raffinose, stachyose와 guar gum 등의 α-galactosidic 결합을 하고 있는 당을 분해하는 효소이다. 장내세균중 우익균이며 우세균주인 Bifidobacteria로부터 α-galactosidase의 효소학적 특성을 알아보기 위하여 배양여액으로부터 ammonium sulfate분획, 핵산의 제거, Sephadex G-200 gel filtration 및 DEAE-Sephadex A-50 ion exchange chromatography 등의 4단계 정제과정을 거쳐 정제한 결과 약 8배로 정제되어 단일 단백질로 분리하였다. 또한, 효소분해산물을 알아보기 위하여 TLC에 의하여 당분해 및 올리고당의 생성을 알아보았다. 정제효소의 활성 최적온도는 37℃, 최적 pH는 7.0이었다. 효소활성이 K^+, Zn^2+과 같은 금속이온과 8-Hydroxyquinoline, Sodium Bisulfite 등에 의해선 그다지 저해되지 않았으나, Hg^+, Cu^2+과 p-Chloromercuribenzoic acid에 의해선 저해되었다. 효소의 분자량이 301, 995, 합성기질인 PNPG에 대한 K_m은 0.069mM, V_max는 347.22μmol/min.mg protein이었다. To elucidate enzymatic properties of α-galactosidase (EC 3.2.1.22) from Bif.angulatum. α-galactosidase was purified to homogeneity by ammonium sulfate fractionation, protamine sulfate precipitation, sephadex G-200 gel filtration, and DEAE-sephadex A-50 ion exchange chromatography. The purified α-galactosidase was found tobbe homogeneous by SDSpolyacrylamide gel electrophoresis. The molecular weight of this enzyme, estimated by sepadex G-200 gel filtration, was about 301,995. The optimum conditions for the enzyme reaction was pH 6.5 to 7.0 at 37℃. The purified enzyme was stable at 45℃ or below and in buffer at pH 6 to 7.0. The activity was inhibited by mercury, copper ion, and p-chloromercuribenzoic acid. The kinetics of this enzyme, with p-nitrophenyl-α-D-galactoside as substrate, was determined : K_m was about 0.069mM and V_mas was 347.22 μmoles/min mg protein.

폐렴으로 병발된 범발성 혈관내 응고증의 Antithrombin III 치험 1례

서중산,최호열,김현수,이록윤,오흥국,박영석,정기석,박근칠,선덕제 한림대학교의료원 1994 人間科學 Vol.18 No.9

TiAIN 코팅 평 엔드밀의 성능평가에 관한 기초 연구

유중학,국정한,김문기 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.5

The purpose of this study is an evaluation of flat end mills to develop appropriate tools for the high speed machining. First of all, several flat end mills which are produced by different markers are selected to analyze the performances of the tools. Experimental works are also executed to measure cutting force, tool wear and surface roughness for different cutting conditions. And then the results are compared and analyzed for developing optimal cutting tool in the high speed condition.

수종의 레진 모노머가 우식 유발성 세균의 활성에 미치는 영향

서영주,국중기,윤정훈,김수관,이난영,이상호 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.2

이전의 연구에서 레진 재료를 포함한 여러 수복재료에서의 유출물이 우식 유발 세균의 성장에 영향을 줄 수 있다는 보고가 있었다. 이번 연구의 목적은 대표적인 우식 유발 세균인 Streptococcus mutans와 Streptococcus sobrinus의 성장에 대하여 레진을 구성하는 모노머들(Bis-GMA, TEGDMA, EGDMA, UDMA, HEMA, Camphoroquinone)이 어떠한 영향을 줄 수 있는지에 대하여 알아보고자 하는 것이다. 결과는 다음과 같다. 1. S. mutans와 S. sorbinus의 성장률은 6가지 레진 모노미 모두에서 0.03 m㏖/L의 농도에 서 유의할 만하게 감소되었다. 2. S. mutans의 성장률은 0.01 m㏖/L 농도의 UDMA의 0.005 m㏖/L, 0.01 m㏖/L 농도의 Camphoroquinone에서 대조군에 비하여 유의할만하게 감소되었다. 3. S. sorbinus의 성장률은 0.01 m㏖/L 농도의 HEMA. UDMA와 0.005 m㏖/L, 0,01 m㏖/L 농도의 Camphoroquinone에서 대조군에 비하여 유의할만하게 감소되었다. 4. S. sorbinus의 성장률은 0.001, 0.01, 0.03 m㏖/L 농도에서 대조군에 비하여 유의할만한 감소를 보였으며 각 실험군들 간에도 통계학적으로 유의할만한 차이를 보였다. 이상의 결과를 종합하면 레진 모노머를 적용한 모든 군에서 적용하지 않은 양성 대조군에 비해 두 세균의 증식률이 감소되었으며, 세균의 성장을 촉진하지 않은 것으로 사료된다. The purpose of this study was to examine the effects of resin composite monomers (Bis-GMA, TEGDMA, EGDMA. UDMA. HEMA, Camphorquinone) on the growth of the two cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus. We obtained the following results : 1. The growth rate of S. mutans and S. sobrinus was decreased significantly in the group of all composite resin monomer at a concentration of 0.03mmoI/L(P〈0.01). 2. The growth rate of S. mutans in the group of UDMA at a concentration of 0.01 mmol/L and the group of CQ at a concentration of 0.005 mmol/L, 0.01 mmol/L 1%-as decreased significantly compared to the control group(P〈0.01). 3. The growth rate of S. sobrinus in the group of HEMA. UDMA at a concentration of 0.01 mmol/L and the group of CQ at a concentration of 0.005mmol/L. 0.0lmmol/L was decreased significantly compared to the control group(P〈0.01). 4. The growth rate of S. sobrinus in the group of EGDMA at a concentration of 0.001, 0.01. 0.03mmol/L was decreased significantly compared t o the control group (P〈0.01) and were showed to be statistically significant difference between experimental groups(P(0.01).

이종 재료 접합부의 응력확대계수

김문기,국정한,유중학,성호현 韓國技術敎育大學校 1996 論文集 Vol.3 No.1

In this study, fracture aspects for dissimilar materials welded by right and left or up and down in symmetry are examined by using Finite Element Method(FEM) in case that holes exist at up and down in symmetry for the center of crack, and the results of this study are as follows ; 1. When the strength(E₁) of a material with a center crack is lower than that (E₂) of the dissimilar material which is welded by right and left in symmetry, the crack propagation rate decreases by about 25%, while it increases by about 20% when the E₁ is higher than E₂. 2. When the E₁ is lower than the E₂ which is welded by up and down in symmetry, the crack propagation rate decreases by about 25% while it increases by about 75% when the E₁ is higher than the E₂. 3. The value of K₁/K?? is constant up to 2.0 in which is the ratio (a/R) between crack length and hole radius, and the value is decreased or increased a little above 2.0. It is regarded that a phenomenon of crack closure is applied according to the welded type of dissimilar material. In addition, It is noticed that retardation effect of crack propagation is changed greatly according to the distributed position of dissimilar material.

각종 치과레이저의 Streptococcus mutans에 대한 증식 기능억제 효과

한강석,국중기,유소영,김화숙,박종휘,박현동,이상훈 大韓小兒齒科學會 2003 大韓小兒齒科學會誌 Vol.30 No.3

레이저의 구강내 산 생성 세균인 S. mutans에 대한 증식 및 기능 억제효과를 평가하기 위하여 S. mutans KCTC 3065가 포함된 세균 pellet에 Er:YAG 레이저와 Nd:YAG 레이저를 비접촉식 방법으로, 조사세기 50mJ, 조사시간 5초, 그리고 pulse repetition rate를 각각 10Hz와 30Hz로 하여 조사하고 세균 군락수, 산 생성능, 불용성 세포외다당류의 합성량을 측정하여 다음과 같은 결과를 얻었다. 1. Chinese ink로 photosensitization을 시행한 후 Nd:YAG 레이저를 조사한 경우가 S. mutans의 증식을 가장 많이 억제하였으며 Er:YAG 레이저 조사도 증식을 억제하였다. Chinese ink를 사용하지 않고 ND:YAG 레이저를 단독으로 조사한 경우는 S. mutans의 증식을 억제하지 못하였다. 2. Chinese ink로 photosensitization을 시행한 후 Nd:YAG 레이저를 조사한 경우가 일정기간 동안 S. mutans의 산생성능을 가장 많이 억제하였으며 Er:YAG 레이저 조사도 산 생성능을 억제하였다. Chinese ink를 사용하지 않고 Nd:YAG 레이저를 단독으로 조사한 경우는 S. mutans의 산 생성능을 억제하지 못하였다. Er:YAG 레이저와 Chinese ink로 photosensitization을 시행한 후 Nd:YAG 레이저를 조사한 경우는 pulse repetition rate가 클수록 전반적으로 세균의 산생성능을 더 많이 억제하였다. 3. 레이저 조사는 S. mutans의 불용성 세포외다당류의 합성에 영향을 미치지 못하였다. 이상의 결과로 보아 Er:YAG 레이저와 Chinese ink로 photosensitization을 시행한 후의 Nd:YAG 레이저 조사는 일정시간 동안 S. mutans의 증식과 산 생성능을 억제시키므로써 치아우식증 예방효과를 얻을 수 있다고 사료되나 억제효과가 오래가지 않아 임상적으로 효과를 얻기 위해서는 자주 조사를 해주어야 한다는 문제점을 안고 있어 임상적으로 치아우식증 예방이란 단독 목적으로 사용하기에는 실용성이 크지 않다고 사료된다. This was performed to evaluate the inhibitory effect of laser on the growth of S. mutans. The bacterial pallets containing S. mutans KCTC 3065 were irradiated with Er:YAG laser and Nd:YAG laser by non-contact method at an intensity of 50mJ for 5 sec with the pulse repetition rates of 10Hz and 30Hz, respectively. The following results were obtained on colony count, acid producing ability, and the amount of insoluble extracellular polysaccharide synthesis. 1. The irradiation of Nd:YAG laser after photosensitization with Chinese ink inhibited the proliferation of S. mutans the most, and the irradiation of Er:YAG also inhibited the proliferation. However, the irradiation of Nd:YAG laser alone could not inhibited the proliferation of S. mutans. The pulse repetition rate did not affect significantly on the proliferation of bacteria in overall. 2. The irradiation of Nd:YAG laser after the photosensitization with Chinese ink inhibited the acid production of S. mutans the most for a certain period of time. Er:YAG laser also inhibited acid production. When Nd:YAG laser was used alone, the acid production of S. mutans was not been inhibited. The irradiation of Nd:YAG laser after photosensitization with Chinese ink inhibited the acid production ability of bacteria the most as the pulse repetition rate increased. 3. Laser irradiation did not inhibited the synthesis of insoluble extracellular polysaccharide of S. mutans. From these results, we conclude that the irradiatioin of Er:YAG laser and Nd:YAG laser after photosensitization with Chinese ink would inhibit the proliferation and acid production by S. mutans, which may prenent dental caries. However, this effect does not last long time so that the laser irradiation should be repeated frequently in order to obtain clinical effect; thus, this laser irradiation would not have a clinical usefulness in preventing dental caries when used solely.

Fusobacterium nucleatum의 테트라사이클린 내성여부를 검사하기 위한 세균배양법과 중합효소연쇄반응법의 비교

최재흥,성진효,국중기,김동기 대한구강보건학회 2003 大韓口腔保健學會誌 Vol.27 No.4

The purposes of this study were to identify the detection and incidence of tetracycline resistance determinant tet(M) by PCR method and to evaluate the availability of PCR method guided for clinical use of antibiotics in dentistry. Subgingival plaque samples were collected from 172 sites of 29 patients. Both original sample and subculturd sample, PCR amplification was used to detect tet(M) in Fusobacterium nucleatum. The percentage of tet(M)-positive subjects and sites in original samples were 100%, 95.9%, respectively. And the percentage of tet(M)-positive subjects and sites in subcultured samples were 17.2%, 3.5%, respectively. In subcultured samples, probing pocket depth and clinical attachment level in tet(M)-positive sites were higher than in negative sites (p<0.05). The sensitivity and specificity of PCR method compared with broth dilution method as a gold standard were 0.91 and 0.86, respectively. The results suggested that tet(M) assay using PCR method was available to detect the tetracycline-resistant F. nucleatum.

중합효소연쇄반응법을 이용한 급성 치수 및 치근단 질환의 병원성 세균의 동정

김지훈,유소영,임선아,국중기,임상수,박슬희,황호길 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.2

The purpose of this study was to investigate the frequency of 7 putative pathogens in endodontic infections. The specimens were collected from infected pulpal tissue of patients who were referred for root canal treatment to the department of conservative dentisty, Chosun University. Samples were collected aseptically using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ml of 1 X PBS. DNAs were extracted from the samples by direct DNA extraction method using lysis buffer (0.5% EDTA, 1% Triton X-100). Identification of 7 putative pathogens was performed by PCR based on 16S rDNA. The target species were as follows: Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, and Treponema denticola. Our data revealed that the prevalence of P.endodontalis was found in 88.6% (39 / 54), P.gingivalis 52.3% (23 / 44), P.nigrescens 18.2%(8 / 44), P.intermedia 15.9% (7 / 44), B.forsythus 18.2% (8 / 44), A.actinomycetemcomitans 2.3% (1 / 44), T.denticola 25% (11 / 44) of the samples. The high prevalence of P. endodontalis and P.gingivalis suggests that they may play an important role in the etiology of endodontic infections.