A Causality Assessment Framework for COVID-19 Vaccines and Adverse Events at the COVID-19 Vaccine Safety Research Center.

During the coronavirus disease 2019 (COVID-19) pandemic, conclusively evaluating possible associations between COVID-19 vaccines and potential adverse events was of critical importance. The National Academy of Medicine of Korea established the COVID-19 Vaccine Safety Research Center (CoVaSC) with support from the Korea Disease Control and Prevention Agency to investigate the scientific relationship between COVID-19 vaccines and suspected adverse events. Although determining whether the COVID-19 vaccine was responsible for any suspected adverse event necessitated a systematic approach, traditional causal inference theories, such as Hill's criteria, encountered certain limitations and criticisms. To facilitate a systematic and evidence-based evaluation, the United States Institute of Medicine, at the request of the Centers for Disease Control and Prevention, offered a detailed causality assessment framework in 2012, which was updated in the recent report by the National Academies of Sciences, Engineering, and Medicine (NASEM) in 2024. This framework, based on a weight-of-evidence approach, allows the independent evaluation of both epidemiological and mechanistic evidence, culminating in a comprehensive conclusion about causality. Epidemiological evidence derived from population studies is categorized into four levels-high, moderate, limited, or insufficient-while mechanistic evidence, primarily from biological and clinical studies in animals and individuals, is classified as strong, intermediate, weak, or lacking. The committee then synthesizes these two types of evidence to draw a conclusion about the causal relationship, which can be described as "convincingly supports" ("evidence established" in the 2024 NASEM report), "favors acceptance," "favors rejection," or "inadequate to accept or reject." The CoVaSC has established an independent committee to conduct causality assessments using the weight-of-evidence framework, specifically for evaluating the causality of adverse events associated with COVID-19 vaccines. The aim of this study is to provide an overview of the weight-of-evidence framework and to detail the considerations involved in its practical application in the CoVaSC.

The m6A writer RBM15 drives the growth of triple-negative breast cancer cells through the stimulation of serine and glycine metabolism.

N6-adenosine methylation (m6A) is critical for controlling cancer cell growth and tumorigenesis. However, the function and detailed mechanism of how m6A methyltransferases modulate m6A levels on specific targets remain unknown. In the current study, we identified significantly elevated levels of RBM15, an m6A writer, in basal-like breast cancer (BC) patients compared to nonbasal-like BC patients and linked this increase to worse clinical outcomes. Gene expression profiling revealed correlations between RBM15 and serine and glycine metabolic genes, including PHGDH, PSAT1, PSPH, and SHMT2. RBM15 influences m6A levels and, specifically, the m6A levels of serine and glycine metabolic genes via direct binding to target RNA. The effects of RBM15 on cell growth were largely dependent on serine and glycine metabolism. Thus, RBM15 coordinates cancer cell growth through altered serine and glycine metabolism, suggesting that RBM15 is a new therapeutic target in BC.

Exploring role of microbatteries in enhancing sustainability and functionality of implantable biosensors and bioelectronics.

Microbatteries are emerging as a sustainable, miniaturized power source, crucial for implantable biomedical devices. Their significance lies in offering high energy density, longevity, and rechargeability, facilitating uninterrupted health monitoring and treatment within the body. The review delves into the development of microbatteries, emphasizing their miniaturization and biocompatibility, crucial for long-term, safe in-vivo use. It examines cutting-edge manufacturing techniques like physical and chemical vapor deposition, and atomic layer deposition, essential for the precision manufacture of the microbatteries. The paper contrasts primary and secondary batteries, highlighting the advantages of zinc-ion and magnesium-ion batteries for enhanced stability and reduced reactivity. It also explores biodegradable batteries, potentially obviating the need for surgical extraction post-use. The integration of microbatteries into diagnostic and therapeutic devices is also discussed, illustrating how they enhance the efficacy and sustainability of implantable biosensors and bioelectronics.

Factors associated with Achilles tendon re-rupture following operative fixation.

Aims: Achilles tendon re-rupture (ATRR) poses a significant risk of postoperative complication, even after a successful initial surgical repair. This study aimed to identify risk factors associated with Achilles tendon re-rupture following operative fixation. Methods: This retrospective cohort study analyzed a total of 43,287 patients from national health claims data spanning 2008 to 2018, focusing on patients who underwent surgical treatment for primary Achilles tendon rupture. Short-term ATRR was defined as cases that required revision surgery occurring between six weeks and one year after the initial surgical repair, while omitting cases with simultaneous infection or skin necrosis. Variables such as age, sex, the presence of Achilles tendinopathy, and comorbidities were systematically collected for the analysis. We employed multivariate stepwise logistic regression to identify potential risk factors associated with short-term ATRR. Results: From 2009 to 2018, the short-term re-rupture rate for Achilles tendon surgeries was 2.14%. Risk factors included male sex, younger age, and the presence of Achilles tendinopathy. Conclusion: This large-scale, big-data study reaffirmed known risk factors for short-term Achilles tendon re-rupture, specifically identifying male sex and younger age. Moreover, this study discovered that a prior history of Achilles tendinopathy emerges as an independent risk factor for re-rupture, even following initial operative fixation.

Organoborane Se and Te Precursors for Controlled Modulation of Reactivity in Nanomaterial Synthesis.

To exploit the distinctive optoelectrical properties of nanomaterials, precise control over the size, morphology, and interface structure is essential. Achieving a controlled synthesis demands precursors with tailored reactivity and optimal reaction temperatures. Here, we introduce organoborane-based selenium and tellurium precursors borabicyclononane-selenol (BBN-SeH) and tellurol (BBN-TeH). The reactivity of these precursors can be modified by commercially available additives, covering a wide range of intermediate reactivity and filling significant reactivity gaps in existing options. By allowing systematic adjustment of growth conditions, they achieve the controlled growth of quantum dots of various sizes and materials. Operating via a surface-assisted conversion mechanism, these precursors rely on surface coordination for activation and undergo quantitative deposition on coordinating surfaces. These properties allow precise control over the radial distribution and density of different chalcogenide atoms within the nanoparticles. Diborabicyclononanyl selane ((BBN)2Se), an intermediate from the BBN-SeH synthesis, can also serve as a selenium precursor. While BBN-SeH suppresses nucleation, (BBN)2Se exhibits efficient nucleation under specific conditions. By leveraging these distinct activation behaviors, we achieved a controlled synthesis of thermally stable nanoplates with different thicknesses. This study not only bridges critical reactivity gaps but also provides a systematic methodology for precise nanomaterial synthesis.

Facemask acne attenuation through modulation of indirect microbiome interactions.

During the COVID-19 pandemic, facemasks played a pivotal role in preventing person-person droplet transmission of viral particles. However, prolonged facemask wearing causes skin irritations colloquially referred to as 'maskne' (mask + acne), which manifests as acne and contact dermatitis and is mostly caused by pathogenic skin microbes. Previous studies revealed that the putative causal microbes were anaerobic bacteria, but the pathogenesis of facemask-associated skin conditions remains poorly defined. We therefore characterized the role of the facemask-associated skin microbiota in the development of maskne using culture-dependent and -independent methodologies. Metagenomic analysis revealed that the majority of the facemask microbiota were anaerobic bacteria that originated from the skin rather than saliva. Previous work demonstrated direct interaction between pathogenic bacteria and antagonistic strains in the microbiome. We expanded this analysis to include indirect interaction between pathogenic bacteria and other indigenous bacteria classified as either 'pathogen helper (PH)' or 'pathogen inhibitor (PIn)' strains. In vitro screening of bacteria isolated from facemasks identified both strains that antagonized and promoted pathogen growth. These data were validated using a mouse skin infection model, where we observed attenuation of symptoms following pathogen infection. Moreover, the inhibitor of pathogen helper (IPH) strain, which did not directly attenuate pathogen growth in vitro and in vivo, functioned to suppress symptom development and pathogen growth indirectly through PH inhibitory antibacterial products such as phenyl lactic acid. Taken together, our study is the first to define a mechanism by which indirect microbiota interactions under facemasks can control symptoms of maskne by suppressing a skin pathogen.

Assessing the Charge Carrier Dynamics at Hybrid Interfaces of Organic Photoanodes for Solar Fuels.

Organic semiconductors (OSCs) have emerged as promising active layers for photoanodes to drive photoelectrochemical (PEC) oxidation reactions. Interfacing an OSC with an inorganic electron transport layer (ETL) is key to enabling both high performance and stability. While spectroelectrochemical techniques have been established for the evaluation of inorganic interfaces, allowing rational optimization toward higher performances, a similar level of understanding for hybrid organic-inorganic interfaces remains elusive. To close this knowledge gap, we first perform a systematic parameter study (ETL thickness, potential dependency, and light intensity) on a state-of-the-art organic photoanode to establish factors determining the photoelectrochemical impedance spectroscopy (PEIS) response. Coupled with in situ UV-Vis characterizations, key charge transfer processes are clearly assigned to the PEIS features.

The activin/BMP-2 chimera AB204 promotes periodontal tissue regeneration in a buccal dehiscence model: a pilot study.

PURPOSE: A combination of activin and bone morphogenetic protein-2 (BMP-2), termed AB204, has been shown to improve osteogenic potential with fewer side effects than BMP-2 alone. This study was performed to evaluate the effect of AB204 on periodontal tissue regeneration in a dog buccal dehiscence model. METHODS: Buccal dehiscence defects were created on the maxillary premolars (P1, P2, and P3) of 6 mongrel dogs. After 5 weeks, the dogs were randomly assigned to 1 of 3 groups: the control, collagen matrix (CM), and CM/AB204 groups. Grafting procedures were then performed. The dogs were sacrificed 8 weeks after the grafting procedure, and volumetric and histological analyses were conducted. RESULTS: The thickness of the buccal gingiva in the CM/AB204 group was greater than those in the other groups at 2 weeks (P<0.05). The ridge width in the AB204/CM group exceeded the width in the other groups at 4 and 8 weeks; however, the difference was not statistically significant. Histological analysis revealed that the CM/AB204 group demonstrated the formation of new bone surrounded by newly formed periodontal ligament and cementum (P=0.035). CONCLUSIONS: The combined application of CM and AB204 shows promise in facilitating the regeneration of periodontal attachment, including the formation of new bone, cementum, and periodontal ligament.

Bone regeneration using activin A/BMP2 chimera (AB204) with collagen membrane in rats with calvarial defects.

PURPOSE: Collagen has long been recognized as an excellent carrier for growth factors, and membrane-type collagen has been widely applied in dentistry for guided bone regeneration. This study was conducted to examine the effects of an activin A/BMP2 chimera (AB204) combined with a collagen membrane (CM) on bone repair in a rat calvarial defect model. METHODS: A unilateral calvarial defect measuring 5.0 mm was surgically created in 32 Sprague-Dawley rats. The rats were then randomly assigned to 1 of 4 groups, each consisting of 8 animals: control (untreated), CM (treated with a CM only), CM/bone morphogenetic protein 2 (BMP2) (treated with a CM and 1.0 µg of BMP2), and CM/AB204 (treated with a CM and 1.0 µg of AB204). Bone regeneration was evaluated using micro-computed tomography (CT) and histological analysis at 2 and 4 weeks following surgery. RESULTS: Micro-CT analysis revealed that bone formation in the CM/BMP2 and CM/AB204 groups was superior to that observed in the control and CM groups at both 2 and 4 weeks postoperatively. BMP2 induced greater bone regeneration than AB204 at 2 weeks; however, AB204 resulted in a greater bone volume at 4 weeks, achieving the highest values recorded. No significant differences were found between the CM/BMP2 and CM/AB204 groups at either time point (P>0.05). On histological examination, new bone formation was evident in both CM/BMP2 and CM/AB204 groups. CONCLUSIONS: Within the limitations of this study, the findings indicate that AB204 may enhance osteogenic potential when used in combination with CM for bone regeneration.

Colon cancer: the 2023 Korean clinical practice guidelines for diagnosis and treatment.

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients' values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Hydrophilic Photocrosslinkers as a Universal Solution to Endow Water Affinity to a Polymer Photocatalyst for an Enhanced Hydrogen Evolution Rate.

A universal approach for enhancing water affinity in polymer photocatalysts by covalently attaching hydrophilic photocrosslinkers to polymer chains is presented. A series of bisdiazirine photocrosslinkers, each comprising bisdiazirine photophores linked by various aliphatic (CL-R) or ethylene glycol-based bridge chains (CL-TEG), is designed to prevent crosslinked polymer photocatalysts from degradation through a safe and efficient photocrosslinking reaction at a wavelength of 365 nm. When employing the hydrophilic CL-TEG as a photocrosslinker with polymer photocatalysts (F8BT), the hydrogen evolution reaction (HER) rate is considerably enhanced by 2.5-fold compared to that obtained using non-crosslinked F8BT photocatalysts, whereas CL-R-based photocatalysts yield HER rates comparable to those of non-crosslinked counterparts. Photophysical analyses including time-resolved photoluminescence and transient absorption measurements reveal that adding CL-TEG accelerates exciton separation, forming long-lived charge carriers. Additionally, the in-depth study using molecular dynamics simulations elucidates the dual role of CL-TEG: it enhances water penetration into the polymer matrix and stabilizes charge carriers after exciton generation against undesirable recombination. Therefore, the strategy highlights endowing a high-permittivity environment within polymer photocatalyst in a controlled manner is crucial for enhancing photocatalytic redox reactivity. Furthermore, this study shows that this hydrophilic crosslinker approach has a broad applicability in general polymer semiconductors and their nanoparticulate photocatalysts.

Immunosuppressive therapy in elderly patients with neuromyelitis optica spectrum disorder: a retrospective multicentre study.

BACKGROUND: The risk-benefit relationship of immunosuppressive therapies (ISTs) for elderly patients with neuromyelitis optica spectrum disorder (NMOSD) is not well established. This study aimed to investigate the safety and efficacy of IST in elderly patients with NMOSD. METHODS: This retrospective study analysed IST efficacy and safety in 101 patients with aquaporin-4 antibody-positive NMOSD aged over 65 years, treated for at least 6 months at five Korean referral centres, focusing on relapse rates, infection events and discontinuation due to adverse outcomes. RESULTS: The mean age at disease onset was 59.8 years, and female-to-male ratio was 4:1. Concomitant comorbidities at NMOSD diagnosis were found in 87 patients (86%). The median Expanded Disability Status Scale score at the initiation of IST was 3.5. The administered ISTs included azathioprine (n=61, 60%), mycophenolate mofetil (MMF) (n=48, 48%) and rituximab (n=41, 41%). Over a median of 5.8 years of IST, 58% of patients were relapse-free. The median annualised relapse rate decreased from 0.76 to 0 (p<0.001), and 81% experienced improved or stabilised disability. Patients treated with rituximab had a higher relapse-free rate than those treated with azathioprine or MMF (p=0.022). During IST, 21 patients experienced 25 severe infection events (SIEs) over the age of 65 years, and 3 died from pneumonia. 14 patients (14%) experienced 17 adverse events that led to switching or discontinuation of IST. When comparing the incidence rates of SIEs and adverse events, no differences were observed among patients receiving azathioprine, MMF and rituximab. CONCLUSION: In elderly patients with NMOSD, IST offers potential benefits in reducing relapse rates alongside a tolerable risk of adverse events.

Impact of COVID-19 Infection and Its Association With Previous Vaccination in Patients With Myasthenia Gravis in Korea: A Multicenter Retrospective Study.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, patients with myasthenia gravis (MG) were more susceptible to poor outcomes owing to respiratory muscle weakness and immunotherapy. Several studies conducted in the early stages of the COVID-19 pandemic reported higher mortality in patients with MG compared to the general population. This study aimed to investigate the clinical course and prognosis of COVID-19 in patients with MG and to compare these parameters between vaccinated and unvaccinated patients in South Korea. METHODS: This multicenter, retrospective study, which was conducted at 14 tertiary hospitals in South Korea, reviewed the medical records and identified MG patients who contracted COVID-19 between February 2022 and April 2022. The demographic and clinical characteristics associated with MG and vaccination status were collected. The clinical outcomes of COVID-19 infection and MG were investigated and compared between the vaccinated and unvaccinated patients. RESULTS: Ninety-two patients with MG contracted COVID-19 during the study. Nine (9.8%) patients required hospitalization, 4 (4.3%) of whom were admitted to the intensive care unit. Seventy-five of 92 patients were vaccinated before contracting COVID-19 infection, and 17 were not. During the COVID-19 infection, 6 of 17 (35.3%) unvaccinated patients were hospitalized, whereas 3 of 75 (4.0%) vaccinated patients were hospitalized (P < 0.001). The frequencies of ICU admission and mechanical ventilation were significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.019 and P = 0.032, respectively). The rate of MG deterioration was significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.041). Logistic regression after weighting revealed that the risk of hospitalization and MG deterioration after COVID-19 infection was significantly lower in the vaccinated patients than in the unvaccinated patients. CONCLUSION: This study suggests that the clinical course and prognosis of patients with MG who contracted COVID-19 during the dominance of the omicron variant of COVID-19 may be milder than those at the early phase of the COVID-19 pandemic when vaccination was unavailable. Vaccination may reduce the morbidity of COVID-19 in patients with MG and effectively prevent MG deterioration induced by COVID-19 infection.

Regulation of Betaine Homocysteine Methyltransferase by Liver Receptor Homolog-1 in the Methionine Cycle.

Betaine-homocysteine S-methyltransferase (BHMT) is one of the most abundant proteins in the liver and regulates homocysteine metabolism. However, the molecular mechanisms underlying Bhmt transcription have not yet been elucidated. This study aimed to assess the molecular mechanisms underlying Bhmt transcription and the effect of BHMT deficiency on metabolic functions in the liver mediated by liver receptor homolog-1 (LRH-1). During fasting, both Bhmt and Lrh-1 expression increased in the liver of Lrh-1f/f mice; however, Bhmt expression was decreased in LRH-1 liver specific knockout mice. Promoter activity analysis confirmed that LRH-1 binds to a specific site in the Bhmt promoter region. LRH-1 deficiency was associated with elevated production of reactive oxygen species (ROS), lipid peroxidation, and mitochondrial stress in hepatocytes, contributing to hepatic triglyceride (TG) accumulation. In conclusion, this study suggests that the absence of an LRH-1-mediated decrease in Bhmt expression promotes TG accumulation by increasing ROS levels and inducing mitochondrial stress. Therefore, LRH-1 deficiency not only leads to excess ROS production and mitochondrial stress in hepatocytes, but also disrupts the methionine cycle. Understanding these regulatory pathways may pave the way for novel therapeutic interventions against metabolic disorders associated with hepatic lipid accumulation.

Unilateral Biportal Endoscopy for L5-S1 Extraforaminal Stenosis (Far Out Syndrome) - Technical Note with Literature Review.

Introduction: Extraforaminal stenosis in L5-S1, or far-out syndrome (FOS), is defined as L5 nerve compression by the transverse process (TP) of the L5 and the ala of the sacrum and disc bulging with/without osteophytes and/or the thickened lumbosacral and extraforaminal ligament. This study aims to describe the unilateral biportal endoscopic decompression technique of the extraforaminal stenosis at L5-S1 or far out syndrome and evaluate its clinical results with a literature review. Case Report: A 44-year-old male presented with severe right sharp shooting pain in the buttock, thigh, leg, foot, and/or toes with numbness in the foot and toes (Visual Analog Scale [VAS] 8/10) for six months with an Oswestry disability index (ODI) score of 70%. Her pain aggravated when bending forward and performing daily routine activities. He also complained of exaggeration of pain in daily regular activities. On physical examination, power in the right lower limbs was 5/5 as per the Medical Research Council (MRC) grading, and deep tendon reflexes were normal. Pre-operative X-ray and CT scan showed no instability or calcified disc osteophyte, and magnetic resonance imaging showed extraforaminal stenosis due to disc herniation at L5-S1 in Figure 1. We performed UBE-L5-S1extraforaminal discectomy surgery to resolve his symptoms. The operative time was 68 min; blood loss was 30 mL. After surgery, the patient was followed up at one week, six weeks, three months, six months, 12 months, and two years. The pain and tingling sensation in the legs improved at the 1-week follow-up, with a VAS score of 0/10 and an ODI score of 10% at the 2-year follow-up. Patient satisfaction was surveyed using Macnab's criteria at the final follow-up visit of 2 years and was found to be excellent. Post-operative imaging showed a good extraforaminal decompression at L5-S. Conclusion: Unilateral biportal endoscopy technique has brought a paradigm shift in the treatment of spinal pathologies and has served as another treatment option for the past two decades. The UBE decompression technique for extraforaminal stenosis at L5-S1 has the advantages of minimally invasive spine surgery; it is a safe and effective treatment option for treating extraforaminal stenosis at L5-S1.

The COVID-19 Vaccine Safety Research Center: a cornerstone for strengthening safety evidence for COVID-19 vaccination in the Republic of Korea.

The COVID-19 Vaccine Safety Research Committee (CoVaSC) was established in November 2021 to address the growing need for independent, in-depth scientific evidence on adverse events (AEs) following coronavirus disease 2019 (COVID-19) vaccination. This initiative was requested by the Korea Disease Control and Prevention Agency and led by the National Academy of Medicine of Korea. In September 2022, the COVID-19 Vaccine Safety Research Center was established, strengthening CoVaSC's initiatives. The center has conducted various studies on the safety of COVID-19 vaccines. During CoVaSC's second research year, from September 29, 2022 to July 19, 2023, the center was restructured into 4 departments: Epidemiological Research, Clinical Research, Communication & Education, and International Cooperation & Policy Research. Its main activities include (1) managing CoVaSC and the COVID-19 Vaccine Safety Research Center, (2) surveying domestic and international trends in AE causality investigation, (3) assessing AEs following COVID-19 vaccination, (4) fostering international collaboration and policy research, and (5) organizing regular fora and training sessions for the public and clinicians. Causality assessments have been conducted for 27 diseases, and independent research has been conducted after organizing ad hoc committees comprising both epidemiologists and clinical experts on each AE of interest. The research process included protocol development, data analysis, interpretation of results, and causality assessment. These research outcomes have been shared transparently with the public and healthcare experts through various fora. The COVID-19 Vaccine Safety Research Center plans to continue strengthening and expanding its research activities to provide reliable, high-quality safety information to the public.

Spot-Based Global Registration for Subpixel Stitching of Single-Molecule Resolution Images for Tissue-Scale Spatial Transcriptomics.

Single-molecule imaging at the tissue scale has revolutionized our understanding of biology by providing unprecedented insight into the molecular expression of individual cells and their spatial organization within tissues. However, achieving precise image stitching at the single-molecule level remains a challenge, primarily due to heterogeneous background signals and dim labeling signals in single-molecule images. This paper introduces Spot-Based Global Registration (SBGR), a novel strategy that shifts the focus from raw images to identified molecular spots for high-resolution image alignment. The use of spot-based data enables straightforward and robust evaluation of the credibility of estimated translations and stitching performance. The method outperforms existing image-based stitching methods, achieving subpixel accuracy (83 ± 36 nm) with exceptional consistency. Furthermore, SBGR incorporates a mechanism to surgically remove duplicate spots in overlapping regions, maximizing information recovery from duplicate measurements. In conclusion, SBGR emerges as a robust and accurate solution for stitching single-molecule resolution images in tissue-scale spatial transcriptomics, offering versatility and potential for high-resolution spatial analysis.

Assessing risk stratification in long-term outcomes of rectal neuroendocrine tumors following endoscopic resection: a multicenter retrospective study.

OBJECTIVES: While endoscopic resection of rectal neuroendocrine tumors (NETs) has significantly increased, long-term data on risk factors for recurrence are still lacking. Our aim is to analyze the long-term outcomes of patients with rectal NETs after endoscopic resection through risk stratification. METHODS: In this multicenter retrospective study, we included patients who underwent endoscopic resection of rectal NETs from 2009 to 2018 and were followed for ≥12 months at five university hospitals. We classified the patients into three risk groups according to the clinicopathological status of the rectal neuroendocrine tumors: low, indeterminate, and high. The high-risk group was defined if the tumors have any of the followings: size ≥ 10 mm, lymphovascular invasion, muscularis propria or deeper invasion, positive resection margins, or mitotic count ≥2/10. RESULTS: A total of 346 patients were included, with 144 (41.6%), 121 (35.0%), and 81 (23.4%) classified into the low-, indeterminate-, and high-risk groups, respectively. Among the high-risk group, seven patients (8.6%) received salvage treatment 28 (27-67) days after the initial endoscopic resection, with no reported extracolonic recurrence. Throughout the follow-up period, 1.1% (4/346) of patients experienced extracolonic recurrences at 56.5 (54-73) months after the initial endoscopic resection. Three of these patients (75%) were in the high-risk group and did not undergo salvage treatment. The risk of extracolonic recurrence was significantly higher in the high-risk group compared to the other groups (p = 0.039). CONCLUSION: Physicians should be concerned about the possibility of metastasis during long-term follow-up of high-risk patients and consider salvage treatment.

Current status and clinical outcome of endoscopic hemostatic powder in gastrointestinal bleeding: a retrospective multicenter study.

Background/Aims: Few multicenter studies have investigated the efficacy of hemostatic powders in gastrointestinal (GI) bleeding. We aimed to investigate the clinical outcomes of hemostatic powder therapy and the independent factors affecting rebleeding rates. Methods: We retrospectively recruited patients who underwent a new hemostatic adhesive powder (UI-EWD; Next-Biomedical) treatment for upper and lower GI bleeding between January 1, 2020 and March 1, 2023. We collected patients' medical records and bleeding lesions. The primary outcomes were clinical and technical success rates, and the secondary outcomes were early, delayed, and refractory bleeding, mortality, and factors affecting early rebleeding rates. Results: This study enrolled 135 patients (age: 67.7±13.6 years, male: 74.1%) from five hospitals. Indications for UI-EWD were peptic ulcers (51.1%), post-procedure-related bleeding (23.0%), and tumor bleeding (19.3%). The clinical and technical success rates were both 97%. The early, delayed, and refractory rebleeding rates were 19.3%, 11.1%, and 12.8%, respectively. Initially elevated blood urea nitrogen (BUN) levels (p=0.014) and Forrest classification IA or IB compared with IIA or IIB (p=0.036) were factors affecting early rebleeding. Conclusions: UI-EWD showed high clinical and technical success rates; however, rebleeding after UI-EWD therapy in patients with initially high BUN levels and active bleeding, according to the Forrest classification, should be considered.

Colon stenting as a bridge to surgery in obstructive colorectal cancer management.

Colonic stent placement is a commonly used bridging strategy for surgery in patients with obstructive colorectal cancer. The procedure involves the placement of a self-expandable metallic stent (SEMS) across the obstructive lesion to restore intestinal patency and alleviate the symptoms of obstruction. By allowing patients to receive surgery in a planned and staged manner with time for preoperative optimization and bowel preparation, stent placement may reduce the need for emergency surgery, which is associated with higher complication rates and poorer outcomes. This review focuses on the role of colon stenting as a bridge to surgery in the management of obstructive colorectal cancer. SEMS as a bridge to surgery for left-sided colon cancer has been demonstrated to be particularly useful; however, further research is needed for its application in cases of right-sided colon cancer. Colon stent placement also has limitations and potential complications including stent migration, re-obstruction, and perforation. However, the timing of curative surgery after SEMS placement remains inconclusive. Considering the literature to date, performing surgery at an interval of approximately 2 weeks is considered appropriate. Therefore, colonic stent placement may be an effective strategy as a bridge to surgery in patients with obstructive colorectal cancer.