• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.254-266
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• 1996

The purpose of this study was to evaluate the degree of marginal leakage that is made by wet bonding to dentin and dissolution of dentinal collagen layer in vivo and in vitro. Class V cavities were prepared to 32 cat's canine teeth and they were randomly assigned into the following 4 groups : Group 1 (not acid conditioned) ; Group 2 (acid-conditioned and blot-dried) ; Group 3 (acid-conditioned and air-dried for 30 seconds) ; Group 4 (acid-conditioned and retreated with 10% NaOCl solution). The acetone-based primer and bonding agent of All Bond 2(Bisco Inc., U.S.A.) and composite resin(Z-100, 3M. Dent. Prod., U.S.A.) were then applied. The resin collar and cap attached to each specimen and 50% silver nitrate solution was placed inside the resin cap for 3 hours. After the canine tooth was resected in level of cervical third, specimens were highly polished and observed the degree of the dye penetration on incisal and gingival margins. The results were as follows ; 1. There was no significant difference of marginal leakage in all the groups between in vivo and in vitro. 2. In vivo, the degree of leakage on the gingival margin showed the lowerest in group 4 and followed by group 2, 3 and group 1 with ascending order. However, there was no statistical difference among all the groups(p>0.05). 3. In vitro, the degree of leakage on the gingival margin showed the lowerest in group 2 and followed by group 4, 3 and group 1 with ascending order. However, there was no significant difference among the experimental groups(p>0.05). 4. The marginal leakage of the incisal margin in vitro was significantly higher in group 1 than the remaining groups(p<0.05).

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2000년도 Proceedings of 2000 KSAM International Symposium and Spring Meeting
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• pp.157-167
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• 2000

A thermostable chitosanase gene from the isolated strain, Bacillus sp. CK4, was cloned, and its complete DNA sequence was determined. The thermostable chitosanase gene was composed of an 822-bp open reading frame which encodes a protein of 242 amino acids and a signal peptide corresponding to a 30 kDa enzyme in size. The deduced amino acid sequence of the chitosanase from Bacillus sp. CK4 exhibits 76.6%, 15.3%, and 14.2% similarities to those from Bacillus subtilis, Bacillus ehemensis, and Bacillus circulans, respectively. C-terminal homology analysis shows that Bacillus sp. CK4 belongs to the Cluster III group with Bacillus subtilis. The size of the gene was similar to that of a mesophile, Bacillus subtilis showing a higher preference for codons ending in G or C. The functional importance of a conserved region in a novel chitosanase from Bacillus sp. CK4 was investigated. Each of the three carboxylic amino acid residues were changed to E50D/Q, E62D/Q, and D66N/E by site-directed mutagenesis. The D66N/E mutants enzymes had remarkably decreased kinetic parameters such as $V_{max}$ and k$\sub$cat/, indicating that the Asp-66 residue was essential for catalysis. The thermostable chitosanase contains three cysteine residues at position 49, 72, and 211. Titration of the Cys residues with DTNB showed that none of them were involved in disulfide bond. The C49S and C72S mutant enzymes were as stable to thermal inactivation and denaturating agents as the wild-type enzyme. However the half-life of the C211S mutant enzyme was less than 60 min at 80$^{\circ}C$, while that of the wild type enzyme was about 90 min. Moreover, the residual activity of C211S was substantially decreased by 8 M urea, and fully lost catalytic activity by 40% ethanol. These results show that the substitution of Cys with Ser at position 211 seems to affect the conformational stability of the chitosanase.

• 원예과학기술지
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• 제29권5호
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• pp.413-419
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• 2011

국내 자생 수생식물인 노랑꽃창포와 창포를 수질 내 카드뮴(Cd) 제거용 식물재료로 이용하고자 Cd 축적과 내성을 조사하였다. Cd 농도에 따른 치사율을 근거로 Cd에 대한 반수치사량($LD_{50}$)을 계산한 결과, 노랑꽃창포는 $78.5{\mu}M$, 창포는 $47.6{\mu}M$로 나타났다. Cd 스트레스에 대해 노랑꽃창포에서는 POD와 SOD, 창포에서는 CAT와 SOD, 폴리페놀이 활성화되었다. 노랑꽃창포에서는 폴리페놀이 측정되지 않았다. 노랑꽃창포와 창포 모두 Cd 처리 농도가 증가하고 기간이 길어질수록 식물체 내 Cd 축적량이 증가하였고, 두 종 모두 지상부보다는 지하부 축적량이 현저하게 많았다. 지상부에 축적된 Cd 함량은 노랑꽃창포 $548.1mg{\cdot}kg^{-1}$(지하부 축적 대비 82.1%) 창포 $121.4mg{\cdot}kg^{-1}$(지하부 축적 대비 13.7%)로 두 종 모두 Cd 고축적식물로 확인되었으며, 특히 노랑꽃 창포가 Cd 축적능력과 내성이 우수하였다.

• 대한의생명과학회지
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• 제17권1호
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• pp.55-60
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• 2011

Skin is a physical barrier against diverse injury and damages. Exposure to ultraviolet (UV) radiation causes detrimental skin injuries such as inflammation and cell death. The value of natural pigments could be applied to many usages including cosmetics. This study was conducted to examine the protective effect of natural pigments extracted from mulberry, balsam pear, purple-colored sweet potato, pehmannia root, gardenia fruit, and black rice against UV-induced cell death in HaCaT cells, human keratinocyte cell lines. In the present study, the exposure of 50 mJ/$cm^2$ UV-B for 24 hr induced cell death in HaCaT cells, which was prevented by the pretreatment of extracts of mulberry, balsam pear, purple-colored sweet potato, rehmannia root, gardenia fruit, and black rice. In addition, the exposure of 50 mJ/$cm^2$ UV-B for 24 hr also increased lipid peroxide (LPO) formation, compared to control in HaCaT cells, which was prevented by the pretreatment of extracts of mulberry, balsam pear, purple-colored sweet potato, rehmannia root, gardenia fruit, and black rice. In conclusion, the extracts of mulberry, balsam pear, purple-colored sweet potato, rehmannia root, gardenia fruit, and black rice prevented the UV-B-induced cell apoptosis via the inhibition of oxidative stress in HaCaT cells.

• Journal of Microbiology and Biotechnology
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• 제8권2호
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• pp.158-164
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• 1998

Crystal structural analyses of the API-TLCK complex revealed that the ${\epsilon}$-amino group (NZ) of the lysyl part of TLCK forms hydrogen bonds with OD1 of $Asp^225$ which is a substrate specificity determinant of API, OG of $Ser^214$, O of $Ser^214$, OG1 of $Thr^189$, and O of $Thr^189$ l89/. The ${\beta}$-carboxyl oxygen of $Asp^225$ forms hydrogen bonds with the NE1 of $Trp^182$. From these observations, it is thought that besides $Asp^225$, $Thr^189$, $Ser^214$, and $Trp^182$ may also contribute to the steric specificity for lysine and high proteolytic activity of API. The side-chain hydroxyl groups of $Thr^189$ and $Ser^214$ were removed to elucidate the role of these hydrogen bonds in the $S_1$-pocket. The $k_{cat}$/$K_m$ of T189V, S214A, and T189V.S214A were decreased to 1/4, 1/3, and 1/46, respectively, of the value for native API. The decreased activities were mainly due to the increase of $K_m$. The CD and fluoroscence spectra of the three mutants were similar to those of wild-type API. With regards to the kinetic parameters ($K_i\;and\;k_2$) of mutants for the reaction involving TLCK and DFP, $k_2$decreased by increase of $K_1$ only. These results suggest that the decreased catalytic activity of these mutants is caused by the partial loss of the hydrogen bond network in the $S_1$-pocket. On the other hand, the similarity of enzymatic properties between W182F and the native enzyme suggests that the hydrogen bond between OD2 of $Asp^225$ and NE1 of $Trp^182$ is not directly related to the reaction of $Asp^225$ with the substrate.

• 한국생태학회:학술대회논문집
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• 한국생태학회 2002년도 VIII 세계생태학대회
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• pp.119-125
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• 2002

Application of phytoremediation in the polluted area to remove undesirable materials is a complex and difficult subject without detailed investigation and experimentation. We investigated the accumulation patterns of cadmium and lead in plants naturally grown, the bioavailability of plants to accumulate these toxic metals and the responses of P. thunbergii to cadmium and lead. The soil samples contained detectable lead (<17.5$\mu\textrm{g}$/g), whereas cadmium was not detected in the soils of study area. The whole body of Persicaria thunbergii contained detectable lead (<320.8$\mu\textrm{g}$/g) but cadmium was detected only in the stem (<7.4$\mu\textrm{g}$/g) and root (<10.4$\mu\textrm{g}$/g) of P. thunbergii. Cadmium was not detected in Trapa japonica and Nymphoides peltata, whereas lead was detected in T. japonica (<323.7$\mu\textrm{g}$/g) and N. peltata (<177.5$\mu\textrm{g}$/g). Correlation coefficient between lead content in soil and in these plant samples represented positive correlation. The total content of lead in each plant sample increased in the order of N.peltata$\leq$P.thunbergii

• The Korean Journal of Ecology
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• 제25권4호
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• pp.253-259
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• 2002

Application of phytoremediation in the polluted area to remove undesirable materials is a complex and difficult subject without detailed investigation and experimentation. We investigated the accumulation patterns of cadmium and lead in plants naturally grown, the bioavailability of plants to accumulate these toxic metals and the responses of P. thunbergii to cadmium and lead. The soil samples contained detectable lead (＜$17.5_\mu$g/g), whereas cadmium was not detected in the soils of study area. The whole body of Persicaria thunbergii contained detectable lead (＜320.$8_\mu$g/g/g) but cadmium was detected only in the stem (＜7.$4_\mu$g/g/g) and root (＜10.$4_\mu$g/g/g) of P. thunbergii. Cadmium was not detected in Trapa japonica and Nymphoides peltata, whereas lead was detected in T. japonica (＜323.$7_\mu$g/g/g) and N. peltata (＜177.$5_\mu$g/g/g). Correlation coefficient between lead content in soil and in these plant samples represented positive correlation. The total content of lead in each plant sample increased in the order of N. peltata$\leq$P. thunbergii

• 한국임상약학회지
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• 제26권4호
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• pp.298-305
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• 2016

Background: This study is to investigate the prescription patterns and factors related to the number of medications treating chronic obstructive pulmonary disease (COPD) in patients under 65 years old according to GOLD guidelines. Methods: We retrospectively analyzed the medical records of patients aged 40-64 years with a diagnosis of COPD from January to March 2016. Patients were classified by combined assessment of COPD (grades A, B, C, D) using spirometry, exacerbation history, mMRC, and/or CAT results. We analyzed prescribed medications, treatment options and factors related to the numbers of COPD medications. Results: The total number of prescriptions were 251. About 35.5% of patients were classified as GOLD A, 34.2% as GOLD B, 17.1% as GOLD C and 13.2% as GOLD D. Inhaled bronchodilator was prescribed for 86.9% of patients and the most frequent COPD medication was long-acting muscarinic antagonist (LAMA) followed by inhaled corticosteroids/long acting beta agonist (ICS/LABA). The majority of low risk patients (GOLD A/B) were prescribed a monotherapy with LAMA or LABA. For high risk patients (GOLD C/D), combination treatment with ICS+LAMA+LABA was mostly prescribed. The 21.2% of patients in GOLD D received systemic corticosteroid. The average number of medications per prescription was 3.7, and this number increased with increasing COPD grade, COPD duration and lung function reduction ($FEV_1$, $FEV_1/FVC$). Conclusion: Generally high adherence to GOLD guideline recommendations was reported. Given the progressive nature of the disease, results suggest that closer attention to respiratory symptoms for early detection, diagnosis, and appropriate treatment of COPD is warranted.

• BMB Reports
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• 제32권1호
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• pp.39-44
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• 1999

Pyruvate decarboxylase (PDC) catalyzes the conversion of pyruvate to acetaldehyde as the penultimate step in alcohol fermentation. The enzyme requires two cofactors, thiamin diphosphate (ThDP) and $Mg^{2+}$, for activity. Zymomonas mobilis PDC shows a strong preference for pyruvate although it will use the higher homologues 2-ketobutyrate and 2-ketovalerate to some extent. We have investigated the effect of mutagenesis of valine 111 and leucine 112 on the substrate specificity. V111 was replaced by glycine, alanine, leucine, and isoleucine while L112 was replaced by alanine, valine, and isoleucine. With the exception of L112I, all mutants retain activity towards pyruvate with $k_{cat}$ values ranging from 40% to 139% of wild-type. All mutants show changes from wild-type in the affinity for ThDP, and several (V111A, L112A, and L112V) show decreases in the affinity for $Mg^{2+}$. Two of the mutants, V111G and V111A, show an increase in the $K_m$ for pyruvate. The activity of each mutant towards 2-ketobutyrate and 2-ketovalerate was investigated and some changes from wild-type were found. For the V111 mutants, the most notable of these is a 3.7-fold increase in the ability to use 2-ketovalerate. However, the largest effect is observed for the L112V mutation which increases the ability to use both 2-ketobutyrate (4.3-fold) and 2-ketovalerate (5.7-fold). The results suggest that L112 and, to a lesser extent, V111 are close to the active site and may interact with the alkyl side-chain of the substrate.

• 대한약리학회지
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• 제17권1호
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• pp.9-15
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• 1981

부자성분중 강심효과를 나타내는 부자부타놀분획의 작용기전을 심근수축기전이 있어서 중심적인 역활을 하는 칼슘이온과의 상호관계에서 검토하였으며 아울러 동물생체내 혈동력학에 대한 영향을 관찰하였다. 부자부타놀분획 적출 고양이 유두근표본의 수축력증가작용에 있어서 심근외칼슘과 상승적이었으며 부자부타놀분획 $10^{-4}g/ml$는 칼슘 0.06mM과 동등한 심근수측증강 효과를 나타내었다. 심근세포막의 칼슘통로 억제약물인 verapamil 존재하에서 저하된 유두근 수축력은 부자부타놀분획에 의하여 용량의존적으로 회복되었으며, 이로부터 부자부타놀분획의 강심작용기전의 일부는 심근세포막의 완만내향성 칼슘통로를 통한 칼슘유입을 측진하는 것과 관계가 있을 것으로 추측하였다. 정상가토의 혈동력학에 있어서 부자부타놀분획은 디지탈리스배당체와는 달리 용량의존적으로 전신동맥압을 저하시키고, 경동맥혈류량을 증가시켰으며, 심박동수에는 크게 의미있는 변화를 보이지 않았다.