1.Antimicrobial effect of infrared diode laser utilizing indocyanine green against Staphylococcus aureus biofilm on titanium surface
Seung Gi KIM ; Si-Young LEE ; Jong-Bin LEE ; Heung-Sik UM ; Jae-Kwan LEE
Journal of Dental Rehabilitation and Applied Science 2024;40(2):55-63
Purpose:
This study aimed to assess the antimicrobial efficacy of an 810-nm infrared diode laser with indocyanine green (ICG) against Staphylococcus aureus on sandblasted, large grit, and acid-etched (SLA) titanium surfaces, comparing its effectiveness with alternative chemical decontamination modalities.
Materials and Methods:
Biofilms of S. aureus ATCC 25923 were culturedon SLA titanium disks for 48 hours. The biofilms were divided into five treatment groups: control, chlorhexidine gluconate (CHX), tetracycline (TC), ICG, and 810-nm infrared diode laser with ICG (ICG-PDT). After treatment, colony-forming units were quantified to assess surviving bacteria, and viability was confirmed through confocal laser-scanning microscope (CLSM) imaging.
Results:
All treated groups exhibited a statistically significant reduction in S. aureus (P < 0.05), with notable efficacy in the CHX, TC, and ICG-PDT groups (P < 0.01). While no statistical difference was observed between TC and CHX, the ICG-PDT group demonstrated superior bacterial reduction. CLSM images revealed a higher proportion of dead bacteria stained in red within the ICG-PDT groups.
Conclusion
Within the limitations, ICG-PDT effectively reduced S. aureus biofilms on SLA titanium surfaces. Further investigations into alternative decontamination methods and the clinical impact of ICG-PDT on peri-implant diseases are warranted.
2.Antimicrobial effect of photodynamic therapy on Staphylococcus aureus biofilms on zirconia disks
Hyuk-Soon KWON ; Si-Young LEE ; Jong-Bin LEE ; Heung-Sik UM ; Jae-Kwan LEE
Journal of Dental Rehabilitation and Applied Science 2024;40(4):241-248
Purpose:
Staphylococcus aureus can attach to extracellular matrix components and plasma proteins deposited on biomaterial surfaces, ultimately forming biofilms. Therefore, managing S. aureus is recommended for preventing and treating peri-implant diseases. This study aimed to evaluate the biofilm-forming ability of S. aureus on zirconia surfaces and to assess the efficacy of photodynamic therapy (PDT) in reducing these biofilms.
Materials and Methods:
Biofilm growth analysis showed optimal formation at 48 hours. Therefore, S. aureus ATCC 25923 was inoculated onto a sterilized zirconia disk and cultivated for 48 hours to form the biofilm. Thereafter, the biofilms were treated with phosphate-buffered saline (PBS; control), chlorhexidine (CHX), tetracycline (TC),toluidine blue O (TBO), cold diode laser (laser), or PDT (TBO + laser), with each group consisting of seven disks. The bacterial loadwas quantified using colony-forming unit (CFU) counts, and biofilm viability was evaluated using confocal laser scanning microscopy (CLSM).
Results:
Significant reductions in bacterial counts were observed in the CHX (95.3%), TC (95.0%), and PDT (93.8%) groups compared to the control (P < 0.001). CLSM revealed a greater number of dead bacteria in the CHX, TC and PDT groups compared to that in other groups.
Conclusion
Within its limitations, this study demonstrated that S. aureus can form biofilms on zirconia surfaces. PDT showed similar efficacy to conventional antimicrobial treatments such as CHX and TC for reducing S. aureus biofilms.zirconia
3.Antimicrobial effect of infrared diode laser utilizing indocyanine green against Staphylococcus aureus biofilm on titanium surface
Seung Gi KIM ; Si-Young LEE ; Jong-Bin LEE ; Heung-Sik UM ; Jae-Kwan LEE
Journal of Dental Rehabilitation and Applied Science 2024;40(2):55-63
Purpose:
This study aimed to assess the antimicrobial efficacy of an 810-nm infrared diode laser with indocyanine green (ICG) against Staphylococcus aureus on sandblasted, large grit, and acid-etched (SLA) titanium surfaces, comparing its effectiveness with alternative chemical decontamination modalities.
Materials and Methods:
Biofilms of S. aureus ATCC 25923 were culturedon SLA titanium disks for 48 hours. The biofilms were divided into five treatment groups: control, chlorhexidine gluconate (CHX), tetracycline (TC), ICG, and 810-nm infrared diode laser with ICG (ICG-PDT). After treatment, colony-forming units were quantified to assess surviving bacteria, and viability was confirmed through confocal laser-scanning microscope (CLSM) imaging.
Results:
All treated groups exhibited a statistically significant reduction in S. aureus (P < 0.05), with notable efficacy in the CHX, TC, and ICG-PDT groups (P < 0.01). While no statistical difference was observed between TC and CHX, the ICG-PDT group demonstrated superior bacterial reduction. CLSM images revealed a higher proportion of dead bacteria stained in red within the ICG-PDT groups.
Conclusion
Within the limitations, ICG-PDT effectively reduced S. aureus biofilms on SLA titanium surfaces. Further investigations into alternative decontamination methods and the clinical impact of ICG-PDT on peri-implant diseases are warranted.
4.Antimicrobial effect of photodynamic therapy on Staphylococcus aureus biofilms on zirconia disks
Hyuk-Soon KWON ; Si-Young LEE ; Jong-Bin LEE ; Heung-Sik UM ; Jae-Kwan LEE
Journal of Dental Rehabilitation and Applied Science 2024;40(4):241-248
Purpose:
Staphylococcus aureus can attach to extracellular matrix components and plasma proteins deposited on biomaterial surfaces, ultimately forming biofilms. Therefore, managing S. aureus is recommended for preventing and treating peri-implant diseases. This study aimed to evaluate the biofilm-forming ability of S. aureus on zirconia surfaces and to assess the efficacy of photodynamic therapy (PDT) in reducing these biofilms.
Materials and Methods:
Biofilm growth analysis showed optimal formation at 48 hours. Therefore, S. aureus ATCC 25923 was inoculated onto a sterilized zirconia disk and cultivated for 48 hours to form the biofilm. Thereafter, the biofilms were treated with phosphate-buffered saline (PBS; control), chlorhexidine (CHX), tetracycline (TC),toluidine blue O (TBO), cold diode laser (laser), or PDT (TBO + laser), with each group consisting of seven disks. The bacterial loadwas quantified using colony-forming unit (CFU) counts, and biofilm viability was evaluated using confocal laser scanning microscopy (CLSM).
Results:
Significant reductions in bacterial counts were observed in the CHX (95.3%), TC (95.0%), and PDT (93.8%) groups compared to the control (P < 0.001). CLSM revealed a greater number of dead bacteria in the CHX, TC and PDT groups compared to that in other groups.
Conclusion
Within its limitations, this study demonstrated that S. aureus can form biofilms on zirconia surfaces. PDT showed similar efficacy to conventional antimicrobial treatments such as CHX and TC for reducing S. aureus biofilms.zirconia
5.Antimicrobial effect of infrared diode laser utilizing indocyanine green against Staphylococcus aureus biofilm on titanium surface
Seung Gi KIM ; Si-Young LEE ; Jong-Bin LEE ; Heung-Sik UM ; Jae-Kwan LEE
Journal of Dental Rehabilitation and Applied Science 2024;40(2):55-63
Purpose:
This study aimed to assess the antimicrobial efficacy of an 810-nm infrared diode laser with indocyanine green (ICG) against Staphylococcus aureus on sandblasted, large grit, and acid-etched (SLA) titanium surfaces, comparing its effectiveness with alternative chemical decontamination modalities.
Materials and Methods:
Biofilms of S. aureus ATCC 25923 were culturedon SLA titanium disks for 48 hours. The biofilms were divided into five treatment groups: control, chlorhexidine gluconate (CHX), tetracycline (TC), ICG, and 810-nm infrared diode laser with ICG (ICG-PDT). After treatment, colony-forming units were quantified to assess surviving bacteria, and viability was confirmed through confocal laser-scanning microscope (CLSM) imaging.
Results:
All treated groups exhibited a statistically significant reduction in S. aureus (P < 0.05), with notable efficacy in the CHX, TC, and ICG-PDT groups (P < 0.01). While no statistical difference was observed between TC and CHX, the ICG-PDT group demonstrated superior bacterial reduction. CLSM images revealed a higher proportion of dead bacteria stained in red within the ICG-PDT groups.
Conclusion
Within the limitations, ICG-PDT effectively reduced S. aureus biofilms on SLA titanium surfaces. Further investigations into alternative decontamination methods and the clinical impact of ICG-PDT on peri-implant diseases are warranted.
6.Antimicrobial effect of photodynamic therapy on Staphylococcus aureus biofilms on zirconia disks
Hyuk-Soon KWON ; Si-Young LEE ; Jong-Bin LEE ; Heung-Sik UM ; Jae-Kwan LEE
Journal of Dental Rehabilitation and Applied Science 2024;40(4):241-248
Purpose:
Staphylococcus aureus can attach to extracellular matrix components and plasma proteins deposited on biomaterial surfaces, ultimately forming biofilms. Therefore, managing S. aureus is recommended for preventing and treating peri-implant diseases. This study aimed to evaluate the biofilm-forming ability of S. aureus on zirconia surfaces and to assess the efficacy of photodynamic therapy (PDT) in reducing these biofilms.
Materials and Methods:
Biofilm growth analysis showed optimal formation at 48 hours. Therefore, S. aureus ATCC 25923 was inoculated onto a sterilized zirconia disk and cultivated for 48 hours to form the biofilm. Thereafter, the biofilms were treated with phosphate-buffered saline (PBS; control), chlorhexidine (CHX), tetracycline (TC),toluidine blue O (TBO), cold diode laser (laser), or PDT (TBO + laser), with each group consisting of seven disks. The bacterial loadwas quantified using colony-forming unit (CFU) counts, and biofilm viability was evaluated using confocal laser scanning microscopy (CLSM).
Results:
Significant reductions in bacterial counts were observed in the CHX (95.3%), TC (95.0%), and PDT (93.8%) groups compared to the control (P < 0.001). CLSM revealed a greater number of dead bacteria in the CHX, TC and PDT groups compared to that in other groups.
Conclusion
Within its limitations, this study demonstrated that S. aureus can form biofilms on zirconia surfaces. PDT showed similar efficacy to conventional antimicrobial treatments such as CHX and TC for reducing S. aureus biofilms.zirconia
7.Clinical Effect of Endosonography on Overall Survival in Patients with Radiological N1 Non–Small Cell Lung Cancer
Bo-Guen KIM ; Byeong-Ho JEONG ; Goeun PARK ; Hong Kwan KIM ; Young Mog SHIM ; Sun Hye SHIN ; Kyungjong LEE ; Sang-Won UM ; Hojoong KIM ; Jong Ho CHO
Cancer Research and Treatment 2024;56(2):502-512
Purpose:
It is unclear whether performing endosonography first in non–small cell lung cancer (NSCLC) patients with radiological N1 (rN1) has any advantages over surgery without nodal staging. We aimed to compare surgery without endosonography to performing endosonography first in rN1 on the overall survival (OS) of patients with NSCLC.
Materials and Methods:
This is a retrospective analysis of patients with rN1 NSCLC between 2013 and 2019. Patients were divided into ‘no endosonography’ and ‘endosonography first’ groups. We investigated the effect of nodal staging through endosonography on OS using propensity score matching (PSM) and multivariable Cox proportional hazard regression analysis.
Results:
In the no endosonography group, pathologic N2 occurred in 23.0% of patients. In the endosonography first group, endosonographic N2 and N3 occurred in 8.6% and 1.6% of patients, respectively. Additionally, 51 patients were pathologic N2 among 249 patients who underwent surgery and mediastinal lymph node dissection (MLND) in endosonography first group. After PSM, the 5-year OSs were 68.1% and 70.6% in the no endosonography and endosonography first groups, respectively. However, the 5-year OS was 80.2% in the subgroup who underwent surgery and MLND of the endosonography first group. Moreover, in patients receiving surgical resection with MLND, the endosonography first group tended to have a better OS than the no endosonography group in adjusted analysis using various models.
Conclusion
In rN1 NSCLC, preoperative endosonography shows better OS than surgery without endosonography. For patients with rN1 NSCLC who are candidates for surgery, preoperative endosonography may help improve survival through patient selection.
8.Noninferiority Outcomes of Besifovir Compared to Tenofovir Alafenamide in Treatment-Naïve Patients with Chronic Hepatitis B
Tae Hyung KIM ; Ji Hoon KIM ; Hyung Joon YIM ; Yeon Seok SEO ; Sun Young YIM ; Young-Sun LEE ; Young Kul JUNG ; Jong Eun YEON ; Soon Ho UM ; Kwan Soo BYUN
Gut and Liver 2024;18(2):305-315
Background/Aims:
Besifovir dipivoxil maleate (BSV) and tenofovir alafenamide fumarate (TAF) have been recently approved in Korea as the initial antiviral agents for chronic hepatitis B (CHB).However, the real-world outcome data for these drugs remain limited. Therefore, we conducted a noninferiority analysis using real-world data to compare the clinical outcomes of the two nucleotide analogs in treatment-naïve patients with CHB.
Methods:
We retrospectively investigated a cohort of patients with CHB who received BSV or TAF as first-line antiviral agents. The endpoints were virological response (VR) and liver-related clinical outcomes.
Results:
A total of 537 patients, consisting of 202 and 335 patients administered BSV and TAF, respectively, were followed up for 42 months. No significant difference was observed between the VRs of the patients from the two groups. The rates of biochemical response, virologic breakthrough, and incidence rates of hepatocellular carcinoma did not differ between the groups. However, the hepatitis B e antigen seroclearance rate was higher and the renal function declined less in the BSV group. Multivariable analysis indicated older age, alcohol abuse, cirrhosis and ascites, and lower serum HBV DNA level to be independently associated with increased hepatocellular carcinoma risk. The 1:1 propensity score-matched analysis with 400 patients showed VR rates of 85.0% and 88.7% in the BSV and TAF group patients, respectively, at 2 years. The absolute value of the 95% confidence interval for the difference (–0.04 to 0.12) satisfied the a priori limit of a noninferiority of 0.15.
Conclusions
BSV is noninferior to TAF in terms of VR, and their clinical outcomes are comparable to CHB.
9.Magnitude and Duration of Serum Neutralizing Antibody Titers Induced by a Third mRNA COVID-19 Vaccination against Omicron BA.1 in Older Individuals
Jun-Sun PARK ; Jaehyun JEON ; Jihye UM ; Youn Young CHOI ; Min-Kyung KIM ; Kyung-Shin LEE ; Ho Kyung SUNG ; Hee-Chang JANG ; BumSik CHIN ; Choon Kwan KIM ; Myung-don OH ; Chang-Seop LEE
Infection and Chemotherapy 2024;56(1):25-36
Background:
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (B.1.1.529) is dominating coronavirus disease 2019 (COVID-19) worldwide. The waning protective effect of available vaccines against the Omicron variant is a critical public health issue. This study aimed to assess the impact of the third COVID-19 vaccination on immunity against the SARS-CoV-2 Omicron BA.1 strain in older individuals.
Materials and Methods:
Adults aged ≥60 years who had completed two doses of the homologous COVID-19 vaccine with either BNT162b2 (Pfizer/BioNTech, New York, NY, USA, BNT) or ChAdOx1 nCoV (SK bioscience, Andong-si, Gyeongsangbuk-do, Korea, ChAd) were registered to receive the third vaccination. Participants chose either BNT or mRNA-1273 (Moderna, Norwood, MA, USA, m1273) mRNA vaccine for the third dose and were categorized into four groups: ChAd/ChAd/BNT, ChAd/ChAd/m1273, BNT/BNT/BNT, and BNT/BNT/m1273. Four serum specimens were obtained from each participant at 0, 4, 12, and 24 weeks after the third dose (V1, V2, V3, and V4, respectively).Serum-neutralizing antibody (NAb) activity against BetaCoV/Korea/KCDC03/2020 (NCCP43326, ancestral strain) and B.1.1.529 (NCCP43411, Omicron BA.1 variant) was measured using plaque reduction neutralization tests. A 50% neutralizing dilution (ND 50 ) >10 was considered indicative of protective NAb titers.
Results:
In total, 186 participants were enrolled between November 24, 2021, and June 30, 2022. The respective groups received the third dose at a median (interquartile range [IQR]) of 132 (125 - 191), 123 (122 - 126), 186 (166 -193), and 182 (175 - 198) days after the second dose. Overall, ND 50 was lower at V1 against Omicron BA.1 than against the ancestral strain. NAb titers against the ancestral strain and Omicron BA.1 variant at V2 were increased at least 30-fold (median [IQR], 1235.35 [1021.45 - 2374.65)] and 129.8 [65.3 - 250.7], respectively). ND 50 titers against the ancestral strain and Omicron variant did not differ significantly among the four groups (P= 0.57). NAb titers were significantly lower against the Omicron variant than against the ancestral strain at V3 (median [IQR], 36.4 (17.55 - 75.09) vs. 325.9 [276.07 - 686.97]; P = 0.012). NAb titers against Omicron at V4 were 16 times lower than that at V3. Most sera exhibited a protective level (ND 50 >10) at V4 (75.0% [24/32], 73.0% [27/37], 73.3% [22/30], and 70.6% [12/17] in the ChAd/ChAd/BNT, ChAd/ChAd/m1273, BNT/BNT/BNT, and BNT/BNT/m1273 groups, respectively), with no significant differences among groups (P = 0.99).
Conclusion
A third COVID-19 mRNA vaccine dose restored waning NAb titers against Omicron BA.1. Our findings support a third-dose vaccination program to prevent the waning of humoral immunity to SARS-CoV-2.
10.Improved anti-fibrotic effects by combined treatments of simvastatin and NS-398 in experimental liver fibrosis models
Seong Hee KANG ; Hyung Joon YIM ; Ji-won HWANG ; Mi-jung KIM ; Young-Sun LEE ; Young Kul JUNG ; Hyungshin YIM ; Baek-Hui KIM ; Hae-Chul PARK ; Yeon Seok SEO ; Ji Hoon KIM ; Jong Eun YEON ; Soon Ho UM ; Kwan Soo BYUN
The Korean Journal of Internal Medicine 2022;37(4):745-756
Background/Aims:
Efficient anti-fibrotic therapies are required for the treatment of liver cirrhosis. Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) and cyclooxygenase-2 (COX-2) inhibitors have been reported to have anti-fibrotic effects. Here, we investigated whether combined treatment with a statin and a COX-2 inhibitor has synergistic anti-fibrotic effects.
Methods:
The effects of treatment strategies incorporating both simvastatin and a COX-2 inhibitor, NS-398, were investigated using an immortalized human hepatic stellate cell line (LX-2) and a hepatic fibrosis mouse model developed using thioacetamide (TAA) in drinking water. Cellular proliferation was investigated via 5-bromo-2-deoxyuridine uptake. Pro- and anti-apoptotic factors were investigated through Western blotting and real-time polymerase chain reaction analysis.
Results:
The evaluation of the anti-proliferative effects on LX-2 cells showed that the observed effects were more pronounced with combination therapy than with single-drug therapy. Moreover, hepatic fibrosis and collagen deposition decreased significantly in TAA-treated mice in response to the combined treatment strategy. The mechanisms underlying the anti-fibrotic effects of the combination therapy were investigated. The effects of the combination therapy were correlated with increased expression levels of extracellular signal-regulated kinase 1/2 signaling molecules, upregulation of the Bax/Bcl-2 signaling pathway, inhibition of the transforming growth factor-β signaling pathway, and inhibition of tissue inhibitor of matrix metalloproteinases 1 and 2.
Conclusions
The combination of simvastatin and NS-398 resulted in a synergistic anti-fibrotic effect through multiple pathways. These findings offer a theoretical insight into the possible clinical application of this strategy for the treatment of advanced liver diseases with hepatic fibrosis.

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