• 대한치주과학회:학술대회논문집
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• 2000.11a
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• pp.160-160
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• 2000

• 대한치주과학회:학술대회논문집
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• 2000.11a
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• pp.71-71
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• 2000

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.625-639
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• 1996

The purpose of this study was to an in estimate the antibiotic susceptibility of P. gingivalis and P. interrnedia isolate from the subgingival plaque to adult periodontitis. Six P. gingivalis and five P. intermedia bacterial strains were tested for their susceptibility to 10 antimicrobial agents under disc diffusion method and broth dilution method. Ten patients with deep pocket(6mm) were selected for this study. They had not taken antibiotics for 6 months and no history of dental treatment for 6 months before this study. The result were as follow : 1. For antibiotic disc diffusion method, six P. gingivalis and five P. interrnedia were tested with 10 antimicrobial agents which comprised penicillin, gentamycin, clindamycin, lincomycin, ampicillin, erythromycin, tetracycline, amikacin, chloramphenicol, vancomycin. The sensitive antibiotics were tetracycline, penicillin, ampicillin, vancomycin, chloramphenicol and resisitent antibiotics were lincomycin. The other antimicrobial agents were less active. 2. From the study of determination on the minimal inhibitory concentration(MIC) by broth dilution method, the MIC of tetracycline to P. gingivalis and P. intermedia were $0.5-1.0{\mu}g/ml$, $0.5{\mu}g/ml$, that of ampicillin were $1-8{\mu}g/ml$, that of clindamycin were $1-32{\mu]g/ml$, $8-16{\mu}g/ml$, that of lincomycin were $16-32{\mu}g/ml$, $2-32{\mu}g/ml$. These data suggest that tetracycline and ampicillin may be valuable drug in the elemination of P. gingivalis and P. interrnedia from the patients with adult periodontitis.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.963-979
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• 1999

This study examined ribotypes of 36 P. gingivalis strains isolated from 10 rapidly progressive periodontitis patients in Korean and revealed the presence of genetic heterogeneity among the patients. Ribotyping was performed by using a oligonucleotide probes based on 16S rRNA after whole genomic DNA had been digested with the restriction endonuclease enzyme Kpn I and Pst I. In addition, the antigenic heterogeneity of fimbrillin and protease activity was analysed to observe the virulency of P. gingivalis. The results were as follows. 1. Using KpnI, 6 ribotypes were detected, whereas 7 ribotypes were identified by using PstI. When combined two enzymes, a total of 8 ribotypes was subgrouped. 2. Ribotype I/e was the most common and detected in 4 among 10 patients. 3. The fimbrillin expressed from P. gingivalis isolates had the molecular size of 41kDa, 43kDa, 49kDa. It was observed that the size of fimbrillin with the same ribotypes could be identical. 4. All the P. gingivalis strains showed strong proteolytic activity and had the molecular size more than 120kDa. In summary, total 8 ribotypes were observed for isolates from rapidly progressive periodontitis patients. Forty percent of the patients harbored isolates exhibiting the same ribotype I/e, and it was observed that more than one ribotype can coexist in an individual patient.

• The korean journal of orthodontics
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• v.52 no.4
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• pp.278-286
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• 2022

Objective: To evaluate differences in the adhesion levels of the most common oral pathogens, Streptococcus mutans and Porphyromonas gingivalis, in human saliva-derived microcosm biofilms with respect to time and raw materials of orthodontic brackets. Methods: The samples were classified into three groups of bracket materials: 1) monocrystalline alumina ceramic (CR), 2) stainless steel metal (SS), and 3) polycarbonate plastic (PL), and a hydroxyapatite (HA) group was used to mimic the enamel surface. Saliva was collected from a healthy donor, and saliva-derived biofilms were grown on each sample. A real-time polymerase chain reaction was performed to quantitatively evaluate differences in the attachment levels of total bacteria, S. mutans and P. gingivalis at days 1 and 4. Results: Adhesion of S. mutans and P. gingivalis to CR and HA was higher than the other bracket materials (SS = PL < CR = HA). Total bacteria demonstrated higher adhesion to HA than to bracket materials, but no significant differences in adhesion were observed among the bracket materials (CR = SS = PL < HA). From days 1 to 4, the adhesion of P. gingivalis decreased, while that of S. mutans and total bacteria increased, regardless of material type. Conclusions: The higher adhesion of oral pathogens, such as S. mutans and P. gingivalis to CR suggests that the use of CR brackets possibly facilitates gingival inflammation and enamel decalcification during orthodontic treatment.

• Journal of Periodontal and Implant Science
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• v.52 no.1
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• pp.28-38
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• 2022

Purpose: Macrophages play crucial roles as early responders to bacterial pathogens and promote/ or impede chronic inflammation in various tissues. Periodontal macrophage-induced pyroptosis results in physiological and pathological inflammatory responses. The transcription factor Dec2 is involved in regulating immune function and inflammatory processes. To characterize the potential unknown role of Dec2 in the innate immune system, we sought to elucidate the mechanism that may alleviate macrophage pyroptosis in periodontal inflammation. Methods: Porphyromonas gingivalis lipopolysaccharide (LPS) was used to induce pyroptosis in RAW 264.7 macrophages. Subsequently, we established an LPS-stimulated Dec2 overexpression cellular model in macrophages. Human chronic periodontitis tissues were employed to evaluate potential changes in inflammatory marker expression and pyroptosis. Finally, the effects of Dec2 deficiency on inflammation and pyroptosis were characterized in a P. gingivalis-treated experimental periodontitis Dec2-knockout mouse model. Results: Macrophages treated with LPS revealed significantly increased messenger RNA expression levels of Dec2 and interleukin (IL)-1β. Dec2 overexpression reduced IL-1β expression in macrophages treated with LPS. Overexpression of Dec2 also repressed the cleavage of gasdermin D (GSDMD), and the expression of caspase-11 was concurrently reduced in macrophages treated with LPS. Human chronic periodontitis tissues showed significantly higher gingival inflammation and pyroptosis-related protein expression than non-periodontitis tissues. In vivo, P. gingivalis-challenged mice exhibited a significant augmentation of F4/80, tumor necrosis factor-α, and IL-1β. Dec2 deficiency markedly induced GSDMD expression in the periodontal ligament of P. gingivalis-challenged mice. Conclusions: Our findings indicate that Dec2 deficiency exacerbated P. gingivalis LPS-induced periodontal inflammation and GSDMD-mediated pyroptosis. Collectively, our results present novel insights into the molecular functions of macrophage pyroptosis and document an unforeseen role of Dec2 in pyroptosis.

• Journal of Life Science
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• v.32 no.1
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• pp.56-62
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• 2022

This study was investigated to evaluate the potential of Stewartia koreana Nakai as an oral healthcare material. The inhibitory effects of extracts on the biofilm formation and fimbriae genes expression of Porphyromonas gingivalis were determined by minimal inhibitory concentrations (MIC), biofilm biomass staining, SEM, and qRT-PCR analysis. The S. koreana Nakai branch was extracted into 70% ethanol, and bacteriostatic MIC of extracts against P. gingivalis were 0.6 mg/ml. In P. gingivalis cultures treated with 0.2-2.0 mg/ml of extract, biofilm production rate was significantly decreased in a concentration-dependent manner. The morphology of treated and untreated samples was observed by SEM, and cell aggregation and biofilm were only observed in those treated with extract. Subsequently, qRT-PCR analysis showed that the mRNA expression on fimbriae genes fimA and fimB was suppressed in a concentration-dependent manner. Based on these results, it can be suggested that S. koreana branch extract has the potential to be used as naturally derived oral healthcare material because of its bacteriostatic action and inhibition of P. gingivalis biofilm formation.

• International Journal of Oral Biology
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• v.33 no.4
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• pp.163-177
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• 2008

Periodontal disease, a form of chronic inflammatory bacterial infectious disease, is known to be a risk factor for cardiovascular disease (CVD). Porphyromonas gingivalis has been implicated in periodontal disease and widely studied for its role in the pathogenesis of CVD. A previous study demonstrating that periodontopathic P. gingivalis is involved in CVD showed that invasion of endothelial cells by the bacterium is accompanied by an increase in cytokine production, which may result in vascular atherosclerotic changes. The present study was performed in order to further elucidate the role of P. gingivalis in the process of atherosclerosis and CVD. For this purpose, invasion of human aortic smooth muscle cells (HASMC) by P. gingivalis 381 and its isogenic mutants of KDP150 ($fimA^-$), CW120 ($ppk^-$) and KS7 ($relA^-$) was assessed using a metronidazole protection assay. Wild type P. gingivalis invaded HASMCs with an efficiency of 0.12%. In contrast, KDP150 failed to demonstrate any invasive ability. CW120 and KS7 showed relatively higher invasion efficiencies, but results for these variants were still negligible when compared to the wild type invasiveness. These results suggest that fimbriae are required for invasion and that energy metabolism in association with regulatory genes involved in stress and stringent response may also be important for this process. ELISA assays revealed that the invasive P. gingivalis 381 increased production of the proinflammatory cytokine interleukin (IL)-$1{\beta}$ and the chemotactic cytokines (chemokine) IL (interleukin)-8 and monocyte chemotactic (MCP) protein-1 during the 30-90 min incubation periods (P<0.05). Expression of RANTES (regulation upon activation, normal T cell expressed and secreted) and Toll-like receptor (TLR)-4, a pattern recognition receptor (PRR), was increased in HASMCs infected with P. gingivalis 381 by RT-PCR analysis. P. gingivalis infection did not alter interferon-$\gamma$-inducible protein-10 expression in HASMCs. HASMC nonspecific necrosis and apoptotic cell death were measured by lactate dehydrogenase (LDH) and caspase activity assays, respectively. LDH release from HASMCs and HAMC caspase activity were significantly higher after a 90 min incubation with P. gingivalis 381. Taken together, P. gingivalis invasion of HASMCs induces inflammatory cytokine production, apoptotic cell death, and expression of TLR-4, a PRR which may react with the bacterial molecules and induce the expression of the chemokines IL-8, MCP-1 and RANTES. Overall, these results suggest that invasive P. gingivalis may participate in the pathogenesis of atherosclerosis, leading to CVD.

• Journal of Life Science
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• v.29 no.12
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• pp.1386-1392
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• 2019

This study investigated the potential of dye plants as natural oral health products. The antibacterial activity of ethanol stem extracts of A. japonica, R. verniciflua Stokes, G. jasminoides, D. morbifera, P. amurense Rupr., and S. japonica against P. gingivalis KCTC 5352, S. mutans KCTC3065, S. downei KCTC3634, S. sanguinis KCTC3284, and S. gordonii KCTC 3286 was confirmed. Among the stem extracts from 6 dye plants grown in Korea, ethanol extract from A. japonica stem (1 mg/disc) showed the highest antibacterial activity against P. gingivalis KCTC5352. The A. japonica stem extracts showed antibacterial activity similar to chlorhexidine, which was used as a positive control. The MIC and MBC of P. gingivalis KCTC5352 were 0.4 mg/ml and 0.6 mg/ml, respectively. The biofilm production rate and cell growth of P. gingivalis KCTC5352 in the cultures treated with 0.2-2.0 mg/ml of A. japonica extract were significantly decreased in a concentration-dependent manner. In addition, the mRNA expression of the superoxide dismutase and fimA associated with fimbriae formation in these cultures was suppressed, also in a concentration-dependent manner. Based on these results, it is concluded that A. japonica stem extracts can be used as an oral health product derived from natural materials, as demonstrated by its antibacterial action against and inhibition of biofilm formation of P. gingivalis KCTC5352.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.134.1-134.1
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• 2003

Tempting to further understanding the biophysical mechanism of action of chlorhexidine, we examined effects of the antimicrobial agent(chlorhexidine digluconate) on rate of rotational mobility of liposomes of total lipids extracted from anaerobic bacterial outer membranes (Porphyromonas gingivalis outer membranes). (omitted)