1.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
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 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
4.A Novel Retractable Robotic Device for Colorectal Endoscopic Submucosal Dissection
Sang Hyun KIM ; Chanwoo KIM ; Bora KEUM ; Junghyun IM ; Seonghyeon WON ; Byung Gon KIM ; Kyungnam KIM ; Taebin KWON ; Daehie HONG ; Han Jo JEON ; Hyuk Soon CHOI ; Eun Sun KIM ; Yoon Tae JEEN ; Hoon Jai CHUN ; Joo Ha HWANG
Gut and Liver 2024;18(4):377-385
Background/Aims:
Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). In this study, we developed a retractable robot-assisted traction device and evaluated its performance in colorectal ESD.
Methods:
An experienced endoscopist performed ESD 18 times on an ex vivo porcine colon using the robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate.
Results:
Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robot-assisted ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 minutes vs 34.3±8.3 minutes, p<0.05). The submucosal dissection speed was significantly faster in the RESD group than in the CESD group (36.8±9.2 mm 2 /min vs 18.1±4.7 mm 2 /min, p<0.05). The blind dissection rate was also significantly lower in the RESD group (12.8%±3.4% vs 35.1%±3.9%, p<0.05). In an in vivo porcine feasibility study, the robotic device was attached to a colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed.
Conclusions
The dissection speed and safety profile improved significantly with the retractable RESD. Thus, our robotic device has the potential to provide simple, effective, and safe multidirectional traction during colonic ESD.
5.Contemporary Statistics of Acute Ischemic Stroke and Transient Ischemic Attack in 2021: Insights From the CRCS-K-NIH Registry
Do Yeon KIM ; Tai Hwan PARK ; Yong-Jin CHO ; Jong-Moo PARK ; Kyungbok LEE ; Minwoo LEE ; Juneyoung LEE ; Sang Yoon BAE ; Da Young HONG ; Hannah JUNG ; Eunvin KO ; Hyung Seok GUK ; Beom Joon KIM ; Jun Yup KIM ; Jihoon KANG ; Moon-Ku HAN ; Sang-Soon PARK ; Keun-Sik HONG ; Hong-Kyun PARK ; Jeong-Yoon LEE ; Byung-Chul LEE ; Kyung-Ho YU ; Mi Sun OH ; Dong-Eog KIM ; Dong-Seok GWAK ; Soo Joo LEE ; Jae Guk KIM ; Jun LEE ; Doo Hyuk KWON ; Jae-Kwan CHA ; Dae-Hyun KIM ; Joon-Tae KIM ; Kang-Ho CHOI ; Hyunsoo KIM ; Jay Chol CHOI ; Joong-Goo KIM ; Chul-Hoo KANG ; Sung-il SOHN ; Jeong-Ho HONG ; Hyungjong PARK ; Sang-Hwa LEE ; Chulho KIM ; Dong-Ick SHIN ; Kyu Sun YUM ; Kyusik KANG ; Kwang-Yeol PARK ; Hae-Bong JEONG ; Chan-Young PARK ; Keon-Joo LEE ; Jee Hyun KWON ; Wook-Joo KIM ; Ji Sung LEE ; Hee-Joon BAE ;
Journal of Korean Medical Science 2024;39(34):e278-
This report presents the latest statistics on the stroke population in South Korea, sourced from the Clinical Research Collaborations for Stroke in Korea-National Institute for Health (CRCS-K-NIH), a comprehensive, nationwide, multicenter stroke registry. The Korean cohort, unlike western populations, shows a male-to-female ratio of 1.5, attributed to lower risk factors in Korean women. The average ages for men and women are 67 and 73 years, respectively.Hypertension is the most common risk factor (67%), consistent with global trends, but there is a higher prevalence of diabetes (35%) and smoking (21%). The prevalence of atrial fibrillation (19%) is lower than in western populations, suggesting effective prevention strategies in the general population. A high incidence of large artery atherosclerosis (38%) is observed, likely due to prevalent intracranial arterial disease in East Asians and advanced imaging techniques.There has been a decrease in intravenous thrombolysis rates, from 12% in 2017–2019 to 10% in 2021, with no improvements in door-to-needle and door-to-puncture times, worsened by the coronavirus disease 2019 pandemic. While the use of aspirin plus clopidogrel for noncardioembolic stroke and direct oral anticoagulants for atrial fibrillation is well-established, the application of direct oral anticoagulants for non-atrial fibrillation cardioembolic strokes in the acute phase requires further research. The incidence of early neurological deterioration (13%) and the cumulative incidence of recurrent stroke at 3 months (3%) align with global figures. Favorable outcomes at 3 months (63%) are comparable internationally, yet the lack of improvement in dependency at 3 months highlights the need for advancements in acute stroke care.
6.Risk of Pancreatic Cancer and Use of Dipeptidyl Peptidase 4 Inhibitors in Patients with Type 2 Diabetes: A Propensity Score-Matching Analysis
Mee Kyoung KIM ; Kyungdo HAN ; Hyuk-Sang KWON ; Soon Jib YOO
Endocrinology and Metabolism 2023;38(4):426-435
Background:
The effects of dipeptidyl peptidase 4 (DPP-4) inhibitors over the course of long-term treatment remain unclear, and concerns have been raised regarding the role of DPP-4 inhibitors in carcinogenesis in the pancreas. Earlier studies of pancreatic adverse events have reported conflicting results.
Methods:
This study analyzed Korean National Health Insurance Service data from January 2009 to December 2012. Patients who had type 2 diabetes mellitus and took two or more oral glucose-lowering drugs (GLDs) were included. Patients prescribed DPP-4 inhibitors (n=51,482) or other GLDs (n=51,482) were matched at a 1:1 ratio using propensity score matching. The risk of pancreatic cancer was calculated using Kaplan-Meier curves and Cox proportional-hazards regression analysis.
Results:
During a median follow-up period of 7.95 years, 1,051 new cases of pancreatic cancer were identified. The adjusted hazard ratio (HR) for DPP-4 inhibitor use was 0.99 (95% confidence interval [CI], 0.88 to 1.12) compared with the other GLD group. In an analysis limited to cases diagnosed with pancreatic cancer during hospitalization, the adjusted HR for the use of DPP-4 inhibitors was 1.00 (95% CI, 0.86 to 1.17) compared with patients who took other GLDs. Using the other GLD group as the reference group, no trend was observed for elevated pancreatic cancer risk with increased DPP-4 inhibitor exposure.
Conclusion
In this population-based cohort study, DPP-4 inhibitor use over the course of relatively long-term follow-up showed no significant association with an elevated risk of pancreatic cancer.
7.Fine Needle Aspiration Cytology vs. Core Needle Biopsy for Thyroid Nodules:A Prospective, Experimental Study Using Surgical Specimen
Hyuk KWON ; Jandee LEE ; Soon Won HONG ; Hyeong Ju KWON ; Jin Young KWAK ; Jung Hyun YOON
Journal of the Korean Radiological Society 2022;83(3):645-657
Purpose:
To evaluate and compare the diagnostic outcomes of ultrasonography (US)-guided fine needle aspiration (FNA) and core needle biopsy (CNB) performed on the same thyroid nodule using a surgical specimen for direct comparison.
Materials and Methods:
We included 89 thyroid nodules from 88 patients from February 2015 to January 2016. The inclusion criterion was thyroid nodules measuring ≥ 20 mm (mean size: 40.0 ± 15.3 mm). Immediately after surgical resection, FNA and subsequent CNB were performed on the surgical specimen under US guidance. FNA and CNB cytopathologic results on the specimen were compared with the surgical diagnosis.
Results:
Among the 89 nodules, 30 were malignant and 59 were benign. Significantly higher inconclusive rates were seen in FNA for malignant than benign nodules (80.0% vs. 39.0%, p < 0.001). For CNB, conclusive and inconclusive rates did not differ between benign and malignant nodules (p = 0.796). Higher inconclusive rates were seen for FNA among cancers regardless of US features, and in the subgroup of size ≥ 40 mm (62.5% vs. 22.9%, p = 0.028). Eleven cancers were diagnosed with CNB (36.7%, 11/30), while none was diagnosed using FNA.
Conclusion
In this experimental study using surgical specimens, CNB showed a potential to provide improved diagnostic sensitivity for thyroid cancer, especially when a conclusive diagnosis is limited with FNA.
8.National Trends in Pediatric CT Scans in South Korea: A Nationwide Cohort Study
Nak Tscheol KIM ; Soon-Sun KWON ; Moon Seok PARK ; Kyoung Min LEE ; Ki Hyuk SUNG
Journal of the Korean Radiological Society 2022;83(1):138-148
Purpose:
This study evaluated the rates and annual trends of pediatric CT scans in South Korea using a nationwide population-based database.
Materials and Methods:
Data regarding pediatric CT scan usage between 2012 and 2017 were retrieved from the health insurance review and assessment service. Data on the age, sex, diagnosis, and the anatomical area of involved patients were also extracted.
Results:
A total of 576376 CT examinations were performed among 58527528 children aged below 18 years (9.8 scans/1000 children), and the number of CT examinations per 1000 children was noted to have increased by 23.2% from 9.0 in 2012 to 11.0 in 2017. Specifically, the number of CT examinations increased by 32.9% for the 6–12 years of age group (7.4/1000 to 9.8/1000) and by 34.0% for the 13–18 years of age group (11.4/1000 to 15.3/1000). Moreover, majority of the CT scans were limited to the head (39.1%), followed by the extremities (32.5%) and the abdomen (13.7%). Notably, the number of extremity CT scans increased by 83.6% (2.3/1000 to 4.2/1000), and its proportion as compared to other scans increased from 25.3% to 37.7%.
Conclusion
CT scans in the pediatric population increased continuously from 2012 to 2017 at an annual rate of 4.4%. Therefore, physicians should balance the benefits of CT with its potential harms from associated radiation exposure in pediatric patients.
9.Blood Loss and Related Laboratory Changes after Single-Event Multilevel Surgery and Hip Reconstructive Surgery in Patients with Cerebral Palsy
Jae Jung MIN ; Soon-Sun KWON ; Kyu Tae KIM ; Ki Hyuk SUNG ; Kyoung Min LEE ; Young CHOI ; Moon Seok PARK
Clinics in Orthopedic Surgery 2021;13(3):406-414
Background:
Single-event multilevel surgery (SEMLS) and hip reconstructive surgery (HRS) often cause intraoperative bleeding, consequently increasing the probability of transfusion and postoperative laboratory changes. Therefore, it is important to assess risk factors to predict the amount of blood loss. This study aimed to evaluate blood loss, its influencing factors, and the related laboratory changes during SEMLS and HRS in patients with cerebral palsy (CP).
Methods:
We retrospectively examined consecutive CP patients who underwent SEMLS and HRS. Surrogate markers of blood loss, including preoperative and postoperative hemoglobin (Hb), hematocrit, and changes in Hb concentration, were assessed. Albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine levels were also analyzed for related laboratory changes. Risk factors were analyzed using multiple regression and logistic regression models.
Results:
The overall cohort comprised 1,188 patients. Of them, 1,007 and 181 underwent SEMLS and HRS, respectively. Furthermore, 72 of 181 patients underwent a concomitant Dega osteotomy. The regression model showed that low preoperative Hb concentration (p < 0.001), high albumin level (p = 0.007), low body mass index (BMI) (p = 0.002), and bilateral HRS (p < 0.001) were significant risk factors of postoperative anemia. Valproate medication was associated with Hb drop, and the risk factors for Hb level < 8 g/dL on postoperative day 2 were bilateral HRS and Dega osteotomy in the HRS subgroup. In total, 21.6% had elevated AST levels on postoperative day 2, and bilateral HRS (p < 0.001), Gross Motor Function Classification System (GMFCS) level V (p = 0.041), Dega osteotomy (p < 0.001), and high preoperative AST level (p < 0.001) increased the risk of AST elevation.
Conclusions
We have summarized the estimated blood loss and related laboratory changes after SEMLS and HRS in patients with CP and identified the risk factors. Clinical guidelines should be accordingly developed to include assessment of these risk factors and their impact in the outcomes of CP patients undergoing SEMLS and HRS.
10.Effect of Dapagliflozin as an Add-on Therapy to Insulin on the Glycemic Variability in Subjects with Type 2 Diabetes Mellitus (DIVE): A Multicenter, Placebo-Controlled, Double-Blind, Randomized Study
Seung-Hwan LEE ; Kyung-Wan MIN ; Byung-Wan LEE ; In-Kyung JEONG ; Soon-Jib YOO ; Hyuk-Sang KWON ; Yoon-Hee CHOI ; Kun-Ho YOON
Diabetes & Metabolism Journal 2021;45(3):339-348
Glycemic variability is associated with the development of diabetic complications and hypoglycemia. However, the effect of sodium-glucose transporter 2 (SGLT2) inhibitors on glycemic variability is controversial. We aimed to examine the effect of dapagliflozin as an add-on therapy to insulin on the glycemic variability assessed using continuous glucose monitoring (CGM) in subjects with type 2 diabetes mellitus. In this multicenter, placebo-controlled, double-blind, randomized study, 84 subjects received 10 mg of dapagliflozin ( At week 12, significant reductions in glycosylated hemoglobin (−0.74%±0.66% vs. 0.01%±0.65%, Dapagliflozin effectively decreased glucose levels, but not glucose variability, after 12 weeks of treatment in participants with type 2 diabetes mellitus receiving insulin treatment. The role of SGLT2 inhibitors in glycemic variability warrants further investigations.

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