Background: Coronavirus disease 2019 (COVID-19) vaccination is effective in preventing the disease transmission and progression. However, the relatively mild disease course of the omicron variant and the decrease in antibodies over time after vaccination raise questions about the effectiveness of vaccination, especially in young people. We compared the prevalence of pneumonia and chest X-ray severity score according to vaccination status among patients < 50 years old with COVID-19. Methods: From January 17 to March 17, 2022, 579 patients with COVID-19, who were < 50 years old and had a known vaccination history in our institution, were all included in this study. All patients underwent initial chest radiography, and follow-up chest radiographs were obtained every two days until discharge. Pneumonia was scored from the radiographs using the Brixia scoring system. The scores of the six lung zones were added for a total score ranging from 0 to 18. Patients were divided into four groups according to 10-year age intervals. Differences between groups were analyzed using the χ2 or Fisher’s exact tests for categorical variables and the Kruskal–Wallis test or analysis of variance for continuous variables. Results: Among patients aged 12–19 years, the prevalence of pneumonia did not differ depending on vaccination status (non-vaccinated vs. vaccinated, 1/47 [2.1%] vs. 1/18 [5.6%]; P = 0.577).Among patients in their 20s, the prevalence of pneumonia was significantly higher among nonvaccinated patients than among vaccinated patients (8/28, 28.6% vs. 7/138, 5.1%, P < 0.001), similar to patients in their 40s (32/52 [61.5%] vs. 18/138 [13.0%]; P < 0.001). The chest X-ray severity score was also significantly higher in non-vaccinated patients than that in vaccinated patients in their 20s to their 40s (P < 0.001), but not among patients aged 12–19 years (P = 0.678). Conclusion In patients aged 20–49 years, vaccinated patients had a significantly lower prevalence of pneumonia and chest X-ray severity score than non-vaccinated patients.

Optic neuritis is a rare extraintestinal manifestation of inflammatory bowel disease. Antitumor necrosis factor alpha (anti-TNF-α) agents are essential treatment options in inflammatory bowel diseases. However, anti-TNF-α agents can implicate optic neuritis and other demyelinating diseases as complications of these agents. We report a patient of infliximab-induced optic neuritis in a patient with ulcerative colitis who was treated with high-dose steroids after discontinuation of infliximab.

Background: Disruption of the rotator cuff muscles compromises concavity compression force, which leads to superior migration of the humeral head and loss of stability. A novel idea of using the magnetic force to achieve shoulder stabilization in massive rotator cuff tears (MRCTs) was considered because the magnets can stabilize two separate entities with an attraction force. This study aimed to investigate the biomechanical effect of the magnetic force on shoulder stabilization in MRCTs. Methods: Seven fresh frozen cadaveric specimens were used with a customized shoulder testing system. Three testing conditions were set up: condition 1, intact rotator cuff without magnets; condition 2, an MRCT without magnets; condition 3, an MRCT with magnets. For each condition, anterior-posterior translation, superior translation, superior migration, and subacromial contact pressure were measured at 0°, 30°, and 60° of abduction. The abduction capability of condition 2 was compared with that of condition 3. Results: The anterior-posterior and superior translations increased in condition 2; however, they decreased compared to condition 2 when the magnets were applied (condition 3) in multiple test positions and loadings (p <0.05). Abduction capability improved significantly in condition 3 compared with that in condition 2, even for less deltoid loading (p < 0.05). Conclusions The magnet biomechanically played a positive role in stabilizing the shoulder joint and enabled abduction with less deltoid force in MRCTs. However, to ensure that the magnet is clinically applicable as a stabilizer for the shoulder joint, it is necessary to thoroughly verify its safety in the human body and to conduct further research on technical challenges.

BACKGROUND: Tissue engineering, including 3D bioprinting, holds great promise as a therapeutic tool for repairing cartilage defects. Mesenchymal stem cells have the potential to treat various fields due to their ability to differentiate into different cell types. The biomimetic substrate, such as scaffolds and hydrogels, is a crucial factor that affects cell behavior, and the mechanical properties of the substrate have been shown to impact differentiation during incubation. In this study, we examine the effect of the mechanical properties of the 3D printed scaffolds, made using different concentrations of cross-linker, on hMSCs differentiation towards chondrogenesis. METHODS: The 3D scaffold was fabricated using 3D bioprinting technology with gelatin/hyaluronic acid (HyA) biomaterial ink. Crosslinking was achieved by using different concentrations of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methlymorpholinium chloride n-hydrate (DMTMM), allowing for control of the scaffold’s mechanical properties. The printability and stability were also evaluated based on the concentration of DMTMM used. The effects of the gelatin/HyA scaffold on chondrogenic differentiation was analyzed by utilizing various concentrations of DMTMM. RESULTS: The addition of HyA was found to improve the printability and stability of 3D printed gelatin/HyA scaffolds.The mechanical properties of the 3D gelatin/HyA scaffold could be regulated through the use of different concentrations of DMTMM cross-linker. In particular, the use of 0.25 mM DMTMM for crosslinking the 3D gelatin/HyA scaffold resulted in enhanced chondrocyte differentiation. CONCLUSION The mechanical properties of 3D printed gelatin/HyA scaffolds cross-linked using various concentrations of DMTMM can influence the differentiation of hMSCs into chondrocytes.

Background: To evaluate the chemosensitivity to doxorubicin (DOX) in two primary cells derived from a tumor of FVB/N-Trp53tm1Hw1 knockout (KO) mice with TALEN-mediated Trp53 mutant gene, we evaluated the cell survivability, cell cycle distribution, apoptotic cell numbers and apoptotic protein expression in solid tumor cells and ascetic tumor cells treated with DOX. Results: The primary tumor cells showed a significant (P < 0.05) defect for UV-induced upregulation of the Trp53 pro-tein, and consisted of different ratios of leukocytes, fibroblasts, epithelial cells and mesenchymal cells. The ­ IC50 level to DOX was lower in both primary cells ­(IC50 = 0.12 μM and 0.20 μM) as compared to the CT26 cells ­(IC50 = 0.32  μM), although the solid tumor was more sensitive. Also, the number of cells arrested at the G0/G1 stage was significantly decreased (24.7–23.1% in primary tumor cells treated with DOX, P < 0.05) while arrest at the G2 stage was enhanced to 296.8–254.3% in DOX-treated primary tumor cells compared with DOX-treated CT26 cells. Furthermore, apoptotic cells of early and late stage were greatly increased in the two primary cell-lines treated with DOX when compared to same conditions for CT26 cells. However, the Bax/Bcl-2 expression level was maintained constant in the primary tumor and CT26 cells. Conclusions To the best of our knowledge, these results are the first to successfully detect an alteration in chemosensitivity to DOX in solid tumor cells and ascetic tumor cells derived from tumor of FVB/N-Trp53tm1Hw1 mice TALENmediated Trp53 mutant gene.

Objective: To compare transverse and longitudinal safe zones using ultrasonography between healthy individuals and patients with carpal tunnel syndrome (CTS). Methods: This was a prospective observational case-control study. Forty wrists from 20 healthy individuals and 40 wrists from 24 patients with CTS were examined. Patients with CTS were classified into three groups (mild, moderate, and severe CTS) based on electrodiagnostic findings. Using ultrasonography, we measured the distance between the median nerve and ulnar vessels to identify the transverse safe zone, and between the distal flexor retinaculum and superficial palmar artery arch to identify the longitudinal safe zone. Results: The transverse and longitudinal safe zones were significantly different between participants with CTS and those without CTS. The transverse safe zone significantly differed between the mild and severe CTS groups, while the longitudinal safe zone was not significantly different between the groups. The cross-sectional area of the median nerve negatively correlated with the transverse and longitudinal safe zones. Conclusion Transverse and longitudinal safe zones were narrower in patients with CTS than in the healthy group. A significant difference was observed between patients with mild CTS and those with severe CTS. Furthermore, the cross-sectional area of the median nerve was directly proportional to the degree of narrowing of the transverse and longitudinal safe zones.

Background/Aims: The clinical characteristics of patients with masked uncontrolled hypertension (MUCH) have been poorly defined, and few studies have investigated the clinical predictors of MUCH. We investigated the demographic, clinical, and blood pressure (BP) characteristics of patients with MUCH and proposed a prediction model for MUCH in patients with hypertension. Methods: We analyzed 1,986 subjects who were enrolled in the Korean Ambulatory Blood Pressure Monitoring (Kor-ABP) Registry and taking antihypertensive drugs, and classified them into the controlled hypertension (n = 465) and MUCH (n = 389) groups. MUCH was defined as the presence of a 24-hour ambulatory mean systolic BP ≥ 130 mmHg and/or diastolic BP ≥ 80 mmHg in patients treated with antihypertensive drugs, having normal office BP. Results: Patients in the MUCH group had significantly worse metabolic profiles and higher office BP, and took significantly fewer antihypertensive drugs compared to those in the controlled hypertension group. Multivariate logistic regression analyses identified high office systolic BP and diastolic BP, prior stroke, dyslipidemia, left ventricular hypertrophy (LVH, ≥ 116 g/m2 for men, and ≥ 96 g/m2 for women), high heart rate (≥ 75 beats/min), and single antihypertensive drug use as independent predictors of MUCH. A prediction model using these predictors showed a high diagnostic accuracy (C-index of 0.839) and goodness-of-fit for the presence of MUCH. Conclusions MUCH is associated with a high-normal increase in office BP and underuse of antihypertensive drugs, as well as dyslipidemia, prior stroke, and LVH, which could underscore achieving optimal BP control. The proposed model accurately predicts MUCH in patients with controlled office BP.

The therapeutic effects of mesenchymal stem cells (MSCs) in musculoskeletal diseases (MSDs) have been verified in many human and animal studies. Although some tissues contain MSCs, the number of cells harvested from those tissues and rate of proliferation in vitro are not enough for continuous transplantation. In order to produce and maintain stable MSCs, many attempts are made to induce differentiation from pluripotent stem cells (iPSCs) into MSCs. In particular, it is also known that the paracrine action of stem cell-secreted factors could promote the regeneration and differentiation of target cells in damaged tissue. MicroRNAs (miRNAs), one of the secreted factors, are small non-coding RNAs that regulate the translation of a gene. It is known that miRNAs help communication between stem cells and their surrounding niches through exosomes to regulate the proliferation and differentiation of stem cells. While studies have so far been underway targeting therapeutic miRNAs of MSDs, studies on specific miRNAs secreted from MSCs are still minimal. Hence, our ultimate goal is to obtain sufficient amounts of exosomes from iPSC-MSCs and develop them into therapeutic agents, furthermore to select specific miRNAs and provide safe cell-free clinical setting as a cell-free status with purpose of delivering them to target cells. This review article focuses on stem cell therapy on MSDs, specific microRNAs regulating MSDs and updates on novel approaches.

Sepsis, one of the most fatal diseases in the world, is known to culminate in multiple organ failure due to an uncontrolled inflammatory response. Hence, the use of animal models in sepsis research is very important to study complex immune responses. The current study was undertaken to compare commercial stocks with KFDA stocks of DBA/2 mice as an animal model for sepsis study. To compare responses of DBA/2 mice to lipopolysaccharides (LPS)-induced sepsis, we measured altered characteristics of various factors associated with sepsis, including survival curves, organ failure and inflammatory response, in DBA/2Korl stock and two commercial stocks (DBA/2A and DBA/ 2B). Survival rates after LPS exposure were similar for DBA/2Korl and DBA/2B; however, for times over 20 h, survival rates were reduced and concentration dependent in DBA/2A. In order to evaluate multiple organ failure caused by sepsis, H&E stains were evaluated for liver and spleen tissues obtained in the early (2 h) and later (20 h) stages after exposure to LPS; no significant differences were observed between the three stocks. mRNA and protein levels of proinflammatory cytokines were assessed for evaluating inflammatory reactions, and were found to increase in a dose-dependent manner in most DBA/2 mice after LPS treatment. However, no changes were observed in the mRNA levels of proinflammatory cytokines at 20 h after LPS exposure in the DBA/2A stock. The induction of inflammation-mediated factors by LPS exposure did not induce alterations in the mRNA levels of COX-2 and iNOS in all three DBA/2 stocks. Our results indicate that response of DBA/2Korl to LPS-induced sepsis is similar to the two commercial DBA/2 stocks, thus representing its potential as a useful biological resource established in Korea.

The therapeutic effects of mesenchymal stem cells (MSCs) in musculoskeletal diseases (MSDs) have been verified in many human and animal studies. Although some tissues contain MSCs, the number of cells harvested from those tissues and rate of proliferation in vitro are not enough for continuous transplantation. In order to produce and maintain stable MSCs, many attempts are made to induce differentiation from pluripotent stem cells (iPSCs) into MSCs. In particular, it is also known that the paracrine action of stem cell-secreted factors could promote the regeneration and differentiation of target cells in damaged tissue. MicroRNAs (miRNAs), one of the secreted factors, are small non-coding RNAs that regulate the translation of a gene. It is known that miRNAs help communication between stem cells and their surrounding niches through exosomes to regulate the proliferation and differentiation of stem cells. While studies have so far been underway targeting therapeutic miRNAs of MSDs, studies on specific miRNAs secreted from MSCs are still minimal. Hence, our ultimate goal is to obtain sufficient amounts of exosomes from iPSC-MSCs and develop them into therapeutic agents, furthermore to select specific miRNAs and provide safe cell-free clinical setting as a cell-free status with purpose of delivering them to target cells. This review article focuses on stem cell therapy on MSDs, specific microRNAs regulating MSDs and updates on novel approaches.