Background: Out-of-hospital cardiac arrest is a major public health concern in Korea.Identifying spatiotemporal patterns of out-of-hospital cardiac arrest incidence and survival outcomes is crucial for effective resource allocation and targeted interventions. Thus, this study aimed to investigate the spatiotemporal epidemiology of out-of-hospital cardiac arrest in Korea, with a focus on identifying high-risk areas and populations and examining factors associated with prehospital outcomes. Methods: We conducted this population-based observational study using data from the Korean out-of-hospital cardiac arrest registry from January 2009 to December 2021. Using a Bayesian spatiotemporal model based on the Integrated Nested Laplace Approximation, we calculated the standardized incidence ratio and assessed the relative risk to compare the spatial and temporal distributions over time. The primary outcome was out-ofhospital cardiac arrest incidence, and the secondary outcomes included prehospital return of spontaneous circulation, survival to hospital admission and discharge, and good neurological outcomes. Results: Although the number of cases increased over time, the spatiotemporal analysis exhibited a discernible temporal pattern in the standardized incidence ratio of out-ofhospital cardiac arrest with a gradual decline over time (1.07; 95% credible interval [CrI], 1.04–1.09 in 2009 vs. 1.00; 95% CrI, 0.98–1.03 in 2021). The district-specific risk ratios of survival outcomes were more favorable in the metropolitan and major metropolitan areas.In particular, the neurological outcomes were significantly improved from relative risk 0.35 (0.31–0.39) in 2009 to 1.75 (1.65–1.86) in 2021. Conclusion This study emphasized the significance of small-area analyses in identifying high-risk regions and populations using spatiotemporal analyses. These findings have implications for public health planning efforts to alleviate the burden of out-of-hospital cardiac arrest in Korea.

Background: Water electrospray technology has been developed and extensively studied for its physical properties and potential application as a non-chemical biocide against airborne pathogens. However, there are still concerns regarding the safety and potential toxicity of inhaling water electrospray (WE) particles. To address these potential hazards and offer insights into the impact of WE on humans, we analyzed the immunopathological response to WE by employing an intranasal challenge C57BL/6 mouse model. This analysis aimed to compare the effects of WE with those of sodium hypochlorite (SH), a well-known biocidal agent. Results: The study findings suggest that the WE did not trigger any pathological immune reactions in the intranasal-challenged C57BL/6 mouse model. Mice challenged with WE did not experience body weight loss, and there was no increase in inflammatory cytokine production compared to SH-treated mice. Histopathological analysis revealed that WE did not cause any damage to the lung tissue. In contrast, mice treated with SH exhibited significant lung tissue damage, characterized by the infiltration of neutrophils and eosinophils. Transcriptomic analysis of lung tissue further confirmed the absence of a pathological immune response in mice treated with WE compared to those treated with SH. Upon intranasal challenge with WE, the C57BL/6 mouse model did not show any evidence of immunopathological damage. Conclusions The results of this study suggest that WE is a safe technology for disinfecting airborne pathogens. It demonstrated little to no effect on immune system activation and pathological outcomes in the intranasal challenge C57BL/6 mouse model. These findings not only support the potential use of WE as an effective and safe method for air disinfection but also highlight the value of the intranasal challenge of the C57BL/6 mouse model in providing significant immunopathological insights for assessing the inhalation of novel materials for potential use.

BACKGROUND: The skin, a vital organ protecting against microorganisms and dehydration, undergoes structural decline with aging, leading to visible issues such as wrinkles and sagging. Reduced blood vessels exacerbate vulnerability, hindering optimal cellular function and compromising skin health. Polydioxanone (PDO) biomaterials address aging concerns but produce acidic byproducts, causing inflammation. Inorganic particles and nitric oxide (NO) play crucial roles in inhibiting inflammation and promoting skin regeneration. Stem cell-derived extracellular vesicles (EVs) contribute to intercellular communication, offering the potential to enhance cell functions. The study proposes a method to enhance PDO-based medical devices by incorporating inorganic particles and immobilizing EVs, focusing on facial rejuvenation, anti-inflammatory response, collagen formation, and angiogenesis.METHOD: PDO composites with inorganic particles such as magnesium hydroxide (MH) and zinc oxide (ZO) were prepared and followed by EV immobilization. Comprehensive characterization included biocompatibility, anti-inflammation, collagen formation ability, and angiogenesis ability. RESULTS: Bulk-modified PDO composites demonstrated even dispersion of inorganic particles, pH neutralization, and enhanced biocompatibility. EVs immobilized on the composite surface exhibited spherical morphology. Inflammationrelated gene expressions decreased, emphasizing anti-inflammatory effects. Collagen-related gene and protein expressions increased, showcasing collagen formation ability. In addition, angiogenic capabilities were notably improved, indicating potential for skin rejuvenation. CONCLUSION The study successfully developed and characterized PDO composites with inorganic particles and EVs, demonstrating promising attributes for medical applications. These composites exhibit biocompatibility, anti-inflammatory properties, collagen formation ability, and angiogenic potential, suggesting their utility in skin rejuvenation and tissue engineering. Further research and clinical validation are essential.

BACKGROUND: Poly(L-lactic acid) (PLLA) is a biodegradable polymer (BP) that replaces conventional petroleumbased polymers. The hydrophobicity of biodegradable PLLA periodontal barrier membrane in wet state can be solved by alloying it with natural polymers. Alloying PLLA with gelatin imparts wet mechanical properties, hydrophilicity, shrinkage, degradability and biocompatibility to the polymeric matrix. METHODS: To investigate membrane performance in the wet state, PLLA/gelatin membranes were synthesized by varying the gelatin concentration from 0 to 80 wt%. The membrane was prepared by electrospinning. RESULTS: At the macroscopic scale, PLLA containing gelatin can tune the wet mechanical properties, hydrophilicity, water uptake capacity (WUC), degradability and biocompatibility of PLLA/gelatin membranes. As the gelatin content increased from 0 to 80 wt%, the dry tensile strength of the membranes increased from 6.4 to 38.9 MPa and the dry strain at break decreased from 1.7 to 0.19. PLLA/gelatin membranes with a gelatin content exceeding 40% showed excellent biocompatibility and hydrophilicity. However, dimensional change (37.5% after 7 days of soaking), poor tensile stress in wet state (3.48 MPa) and rapid degradation rate (73.7%) were observed. The highest WUC, hydrophilicity, porosity, suitable mechanical properties and biocompatibility were observed for the PLLA/40% gelatin membrane. CONCLUSION PLLA/gelatin membranes with gelatin content less than 40% are suitable as barrier membranes for absorbable periodontal tissue regeneration due to their tunable wet mechanical properties, degradability, biocompatibility and lack of dimensional changes.

Background: rhBMP-2 is regarded as the most potent osteoinductive growth factor, and it has been used in the oral cavity with different carriers. The purpose of this study is to evaluate the bone-regenerative effect of rhBMP-2 delivered with different carrier systems through three-dimensional cone beam computed tomography analysis.Method A total of 112 patients underwent oral surgery with rhBMP-2 application (Group 1, n = 53) or without rhBMP-2 application (Group 2, n = 59). Group 1 was divided into 3 groups according to carriers, rhBMP-2 with allograft (Group 1–1, n = 34), rhBMP-2 with xenograft (Group 1–2, n = 5), and rhBMP-2 with absorbable collagen sponge (Group 1–3, n = 14). Cone beam computed tomography scans were taken before surgery (T0) 6 months after surgery (T1). The volume of defects was measured through the three-dimensional image analysis tool. Results: The average bone regeneration rate of Group 1 was significantly greater than that of Group 2. Within Group 1, the group that used allograft as a carrier (Group 1–1) showed significantly higher bone regeneration rates than the group that used absorbable collagen sponge as a carrier (Group 1–3). Conclusion The use of rhBMP-2 after oral surgery results in a superior bone regeneration rate compared to not using rhBMP-2, and its efficacy depends on the carriers it is used with. Allograft affects bone regeneration more than absorbable collagen sponge when it is carried with rhBMP-2. Therefore, the appropriate use of rhBMP-2 with suitable bone grafting materials is useful for promoting postoperative bone regeneration in oral surgery.

Background: Hyposalivation is disease with multiple symptoms. This disease is hard to be diagnosed and to be treated, and there are not enough clinical protocols to cure the disease. In this study, we propose our own treatment protocols which aim not only to cure the disease but also to care for the disease-related symptoms. Methods: At the 1st visit, we collect patient-related information. This procedure includes an intraoral exam, patient history taking, VAS value and unstimulated whole saliva (UWS) measurement, and salivary buffer test. Following the interview and oral examination, objective results are obtained by radiological image, CT, and sialoscintigraphy. At the 2nd visit, we analyze radiographic images including neck CT and salivary scintigraphy. These images can allow accurate diagnosis and help the patients to better understand the current condition. Depending on the severity of symptoms and patient’s discomfort, we try a surgical approach at the 3rd visit, sialendoscopy. Results: With treatment, we can manage the discomfort of patients in daily life. The VAS value of hyposalivation patients dropped gradually with the trial of sialendoscopy. In the case of Sjogren’s syndrome patients, the treatment efficacy has been decreased with low reactivity of treatment. The true meaning of this treatment is in not only curing the disease, but also caring for the disrupted patients. Overall, the amount of UWS increased with the progress after the procedure. Especially in the lower UWS at the 1st visit, there was a more significant increase after the procedure. Conclusion Although many factors that cause hyposalivation have not been identified, the efficacy of sialendoscopy to relieve discomfort in hyposalivation patients has been observed. However, treatment was more difficult and complicated in the group of patients with systemic disease. This study will not only present a treatment protocol for hyposalivation patients, but also consider methods for diagnosing more precisely and improving treatment efficacy. Hyposalivation is a curable and manageable disease in some cases, so interpretation between the clinician and the patient is important.

BACKGROUND: The repair of large bone defects remains a significant challenge in clinical practice and requires bone grafts or substitute materials. In this study, we developed a unique hybrid bone scaffold comprising a three dimensional (3D)-printed metal plate for weight bearing and a biodegradable polymer tube serving as bone conduit. We assessed the long-term effect of the hybrid bone scaffold in repairing radial bone defects in a beagle model. METHODS: Bone defects were created surgically on the radial bone of three beagle dogs and individually-tailored scaffolds were used for reconstruction with or without injection of autologous bone and decellularized extracellular matrix (dECM). The repaired tissue was evaluated by X-ray, micro-computed tomography, and histological observation 6 months after surgery. The functional integrity of hybrid bone scaffold-mediated reconstructions was assessed by gait analysis. RESULTS: In vivo analysis showed that the hybrid bone scaffolds maintained the physical space and bone conductivity around the defect. New bone was formed adjacent to the scaffolds. Addition of autologous bone and dECM in the polymer tube improved healing by enhancing bone induction and osteoconduction. Furthermore, the beagles’ gait appeared normal by 4 months. CONCLUSION The future of bone healing and regeneration is closely related to advances in tissue engineering. Bone production using autologous bone and dECM loaded on 3D-printed hybrid bone scaffolds can successfully induce osteogenesis and provide mechanical force for functional bone regeneration, even in large bone defects.

We would like to thank the authors for their interest in our work. We are grateful for the opportunity to respond to their letter regarding the origin of Jamar dynamometers.We have been delighted to learn about the history and origins of the Jamar dynamometer and believe that this information will be of interest to clinicians and researchers who use dynamometers in clinical settings or for related research. If the authors had not informed us, we would not have known this from the literature. We thank the efforts of the pioneers for their excellent work, which made it possible to objectively evaluate grip strength, and hope that researchers continue their work regarding the accurate measurement of grip strength and its clinical significance.

BACKGROUND: Autologous fat grafting is one of the most common procedures used in plastic surgery to correct soft tissue deficiency or depression deformity. However, its clinical outcomes are often suboptimal, and lack of metabolic and architectural support at recipient sites affect fat survival leading to complications such as cyst formation, calcification.Extracellular matrix-based scaffolds, such as allograft adipose matrix (AAM) and poly(lactic-co-glycolic) acid (PLGA), have shown exceptional clinical promise as regenerative scaffolds. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive to improve biocompatibility. We attempted to combine fat graft with regenerative scaffolds and analyzed the changes and viability of injected fat graft in relation to the effects of injectable natural, and synthetic (PLGA/MH microsphere) biomaterials. METHODS: In vitro cell cytotoxicity, angiogenesis of the scaffolds, and wound healing were evaluated using human dermal fibroblast cells. Subcutaneous soft-tissue integration of harvested fat tissue was investigated in vivo in nude mouse with random fat transfer protocol Fat integrity and angiogenesis were identified by qRT-PCR and immunohistochemistry. RESULTS: In vitro cell cytotoxicity was not observed both in AAM and PLGA/MH with human dermal fibroblast.PLGA/MH and AAM showed excellent wound healing effect. in vivo, the AAM and PLGA/MH retained volume compared to that in the only fat group. And the PLGA/MH showed the highest angiogenesis and anti-inflammation. CONCLUSION In this study, a comparison of the volume retention effect and angiogenic ability between autologous fat grafting, injectable natural, and synthetic biomaterials will provide a reasonable basis for fat grafting.

Previously, most fractures have been treated through bone reduction and immobilization. With an increase in the patients’ need for an early return to their normal function, development in surgical techniques and materials have accelerated. However, delayed union or non-union of the fracture site sometimes inhibits immediate return to normal life. To enhance fracture healing, diverse materials and methods have been developed. This is a review on the current modalities of fracture healing enhancement, which aims to provide a comprehensive knowledge regarding fracture healing for researchers and health practitioners.