Differences in Attentional Bias Toward e-Cigarette Cues Between e-Cigarette Users and Nonusers.

ABSTRACT: The use of electronic nicotine delivery systems (ENDS) has increased rapidly in recent years, particularly among young adults. There is a dearth of research on the cognitive factors that contribute to ENDS use. One of the possible cognitive mechanisms involved with addictive behavior is attentional bias (AB). AB can manifest as either facilitated attention engagement toward or delayed attention disengagement from a relevant stimulus. The purpose of this study was to examine the difference in AB toward ENDS-related cues between ENDS users and non-ENDS users. ENDS users (n = 29) and nonusers (n = 24) between the ages of 18 and 29 years participated in the dot-probe and eye-tracking picture-viewing tasks. The results showed that there was a significant difference in the variance of AB between the two groups. In the eye-tracking task, ENDS users displayed significantly greater net dwell time and fixation time at time frames of 6-9, 9-12, and 12-15 seconds, compared to nonusers. It is noteworthy that ENDS users exhibited attentional fluctuation toward ENDS cues as well as difficulties disengaging attention from ENDS cues. The current findings offer insight into the nature of attentional processes associated with ENDS cues and provide useful data to guide the development of a nurse-led cognitive intervention focusing on biased attentional processing related to ENDS cues.

Prenatal Ultrasound and Magnetic Resonance Findings of Glutaric Acidemia Type 1 and Its Challenges in Prenatal Diagnosis.

Glutaric acidemia type 1 (GA1) presents unique challenges in prenatal diagnosis, especially in cases with no family history. This review article aims to review and present the prenatal ultrasound and magnetic resonance findings of GA1 and consolidate key insights into the difficulties associated with GA1 prenatal diagnosis and the neuroimaging features that require careful differentiation during the diagnostic process.

High-Performance Electrochemical Creatinine Sensors Based on ß-Lead Dioxide/Single-Walled Carbon Nanotube Electrodes.

Creatinine is an important biomarker of kidney function and muscular metabolism. In this paper, we developed the ß-lead dioxide/single-walled carbon nanotube (ß-PbO2/CNT) and the ß-PbO2/CNT ion-selective electrode (ß-PbO2/CNT/ISE), which were used as highly sensitive potentiometric sensors for creatinine detection. The fabricated electrodes exhibited highly pH-sensitive characteristics due to the synergistic effect of the electrochemical properties of CNT and ß-PbO2. Moreover, an ammonium-ion-selective membrane coating allowed the ß-PbO2/CNT electrode to be NH4+-selective for direct detection of the ammonium ion. By exploiting the electrochemical characteristics of these electrodes, the creatinine assay was established through the one-step selective conversion of creatinine by creatinine deiminase, in which the OH- and NH4+ generated by the enzymatic reaction were detected using ß-PbO2/CNT and ß-PbO2/CNT/ISE electrodes as pH- and NH4+-responsive sensors, respectively. The total creatinine assay can be completed within ∼5 min. The assay results from ß-PbO2/CNT and ß-PbO2/CNT/ISE showed excellent sensitivity values of -75.56 and 64.62 mV in the detection range of 10-400 µM with a fast response (20 s), and the limits of detection were calculated to be 0.06 and 0.13 µM, respectively. Moreover, the developed creatinine sensor showed high selectivity against 11 interfering bio/chemical species with negligible interferences (selectivity coefficient <10-4) and excellent repeatability (>97% within 25 cycles) and long-term stability for 4 weeks of storage. In addition, the feasibility and practicality of the device were successfully demonstrated in human serum tests, with recoveries of 95-104% for PbO2/CNT and 92-110% for PbO2/CNT/ISE.

Development of colonic stent simulator using three-dimensional printing technique: a simulator development study in Korea.

Background/Aims: Colonic stenting plays a vital role in the management of acute malignant colonic obstruction. The increasing use of self-expandable metal stents (SEMS) and the diverse challenges posed by colonic obstruction at various locations underscore the importance of effective training for colonic stent placement. Methods: All the components of the simulator were manufactured using silicone molding techniques in conjunction with three-dimensional (3D) printing. 3D images sourced from computed tomography scans and colonoscopy images were converted into a stereolithography format. Acrylonitrile butadiene styrene copolymers have been used in fused deposition modeling to produce moldings. Results: The simulator replicated the large intestine from the rectum to the cecum, mimicking the texture and shape of the human colon. It enables training for colonoscopy insertion, cecum intubation, loop reduction, and stenting within stenotic areas. Interchangeable stenotic modules for four sites (rectum, sigmoid colon, descending colon, and ascending colon) were easily assembled for training. These modules integrate tumor contours and blood vessel structures with a translucent center, allowing real-time visualization during stenting. Successful and repeatable demonstrations of stent insertion and expansion using the reusable SEMS were consistently achieved. Conclusions: This innovative simulator offers a secure colonic stenting practice across various locations, potentially enhancing clinical outcomes by improving operator proficiency during actual procedures.

Traditional herbal medicine Oryeongsan for heart failure: A systematic review and meta-analysis.

Background and objective: Heart failure (HF) is associated with high mortality and hospitalization rates, and its prevalence increases with age. As congestion is the most common cause of hospitalization for HF, diuretics are the most prescribed drugs. However, these agents have side effects due to electrolyte imbalance. In Asian countries, Oryeongsan (ORS) and its variants are used to manage fluid imbalances, including HF congestion. Therefore, ORS is considered a complementary treatment to overcome the limitations of diuretics. This review aimed to elucidate the safety and effectiveness of ORS combined with conventional Western medicine (CWM) for HF. Materials and methods: A literature search was conducted using the PubMed, Embase, CENTRAL, Scopus, CiNii, CNKI, and ScienceON databases to retrieve relevant studies published up to July 2024. Two independent investigators were involved in the data collection and analysis. Randomized controlled trials (RCTs) that evaluated the effects of ORS and its variants in combination with CWM as treatments for HF were selected. The outcome measures included left ventricular ejection fraction (LVEF), total effective rate (TER), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), 6-min Walk Test (6MWT), Minnesota Living with Heart Failure Questionnaire (MLHF-Q), serum brain natriuretic peptide (BNP) level, serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP) level, 24-h urine volume, Lee's score, and New York Heart Association (NYHA) grade I ratio for effectiveness; and incidence of adverse events (AEs) for safety. The methodological quality of the included RCTs was assessed using the Cochrane's Risk of Bias tool. Results: Fifty-nine RCTs that comprised 5069 participants and compared CWM combined with ORS and its variants (treatment group) to CWM alone or CWM plus placebo (control group) were included. Based on the meta-analysis, LVEF was found to significantly improve (mean difference: 6.36, 95 % confidence interval: 5.11 to 7.61, P < 0.00001) in the treatment group. TER, LVEDD, LVESD, 6MWT, MLHF-Q, serum BNP and NT-proBNP levels, 24-h urine volume, Lee's score, and NYHA grade I ratio were also significantly improved in the treatment group compared with the control group with CWM alone. LVEF and TER were improved without significance in the treatment group compared with the control group with CWM plus placebo. The incidence of AEs did not significantly differ between the two groups. Conclusions: Combining CWM with ORS or its variants was more effective than CWM alone in managing HF and could serve as a relatively safe treatment for HF. Further studies are required to validate the findings of the present study.

Development of Ocular Muscle Stimulation Systems and Optimization of Electrical Stimulus Parameters for Paralytic Strabismus Treatment.

Paralysis of the extraocular muscles can lead to complications such as strabismus, diplopia, and loss of stereopsis. Current surgical treatments aim to mitigate these issues by resecting the paralyzed muscle or transposing the other recti muscles to the paralyzed muscle, but they do not fully improve the patient's quality of life. Electrical stimulation shows promise, while requiring further in vivo experiments and research on various stimulation parameters. In this study, we conducted experiments on rabbits to stimulate the superior rectus (SR) muscles using different parameters and stimulation waveforms. To provide various types of electrical stimulation, we developed the ocular muscle stimulation systems capable of both current controlled stimulation (CCS) and high-frequency stimulation (HFS), along with the chip that enables energy-efficient and safe switched-capacitor stimulation (SCS). We also developed electrodes for easy implantation and employed safe and efficient stimulation methods including CCS, SCS, and HFS. The in vivo animal experiments on normal and paralyzed SR muscles of rabbits showed that eyeball abduction angles were proportional to the current and pulse width of the stimulation. With the decaying exponential stimuli of the SCS system, eyeball abductions were 2.58× and 5.65× larger for normal and paralyzed muscles, respectively, compared to the rectangular stimulus of CCS. HFS achieved 0.92× and 0.26× abduction for normal and paralyzed muscles, respectively, with half energy compared to CCS. In addition, the continuous changes in eyeball abduction angle in response to varying stimulation intensity over time were observed.

AB051. Multiple meningiomas developed outside the radiation field after cranial irradiation: a case report.

BACKGROUND: Cranial irradiation has well-known long-term side effects, including radiation-induced neoplasms and vasculopathy. This report describes a case of aggressive and rapid-growing multiple meningiomas developed outside the radiation field after the treatment of medulloblastoma. CASE DESCRIPTION: A 6-year-old boy underwent surgery (gross total resection) and radiotherapy (19.8 Gy for posterior fossa only) against medulloblastoma in the 4th ventricle. The patient could not receive further craniospinal irradiation because of ventriculoperitoneal shunt-related complications. Eighteen years after the radiotherapy, the first meningioma developed in the right temporal convexity, without recurrence of medulloblastoma. It was left untreated because it was asymptomatic. Three years later, the meningioma grew from 0.6 to 6.3 cm3 in volume and another large meningioma (22.1 cm3) developed in the left temporal convexity with additional small meningioma in the right frontal convexity. The left large temporal meningioma showed aggressive nature invading the adjacent temporal bone and temporalis muscle. It was completely resected and the histology revealed as transitional meningioma with 2% of Ki-67. Another new meningioma was identified on the right cerebellar convexity three years post-craniotomy. Subsequent follow-up indicated a progressive increase in the tumor size and gamma knife radiosurgery was performed with right frontal convexity small meningioma. The patient is currently under ongoing surveillance through follow-up assessments. CONCLUSIONS: For patients who received radiotherapy at a young age, clinicians should consider the possibility of secondary neoplasm development even outside the radiation field. Careful imaging follow-up and surgical management are warranted because of the aggressive nature of secondary tumors even though benign in histology.

Structural and quantitative comparison of viral infection-associated N-glycans in plasma from humans, pigs, and chickens: greater similarity between humans and chickens than pigs.

Host N-glycans play an essential role in the attachment, invasion, and infection processes of viruses, including zoonotic infectious diseases. The similarity of N-glycans in the trachea and lungs of humans and pigs facilitates the cross-species transmission of influenza viruses through respiratory tracts. In this study, the structure and quantity of N-glycans in the plasma of humans, pigs, and chickens were analyzed using liquid chromatography-quadrupole-Orbitrap-tandem mass spectrometry. N-glycans in humans (35), pigs (28), and chickens (53) were identified, including the most abundant, species-common, and species-specific N-glycans. Among the N-glycans (relative quantity >0.5%), the sialic acid derivative of N-acetylneuraminic acid was identified in humans (the sum of the relative quantities of each; 64.3%), pigs (45.5%), and chickens (64.4%), whereas N-glycolylneuraminic acid was only identified in pigs (18.1%). Sialylated N-glycan linkage isomers are the influenza virus receptors (α2-6 in humans, α2-3 and α2-6 in pigs, and α2-3 in chickens). Only α2-6 linkages (human, 58.2%; pig, 44.8%; and chicken, 60.6%) were more abundant than α2-3/α2-6 linkages (human, 4.6%; pig, 0.6%; and chicken, 3.4%) and only α2-3 linkages (human, 1.5%; pig, 0.1%; and chicken, 0.4%). Fucosylation, which can promote viral infection through immune modulation, was more abundant in pigs (76.1%) than in humans (36.4%) and chickens (16.7%). Bisecting N-acetylglucosamine, which can suppress viral infection by inhibiting sialylation, was identified in humans (10.3%) and chickens (16.9%), but not in pigs. These results indicate that plasma N-glycans are similar in humans and chickens. This is the first study to compare plasma N-glycans in humans, pigs, and chickens.

Treatment Outcomes after Postoperative Radiotherapy in Triple-Negative Breast Cancer: Multi-Institutional Retrospective Study (KROG 17-05).

BACKGROUND: We designed a multi-institutional retrospective study to investigate the previously unreported failure pattern, survivals, and prognostic factors after postoperative radiotherapy (PORT) in triple negative breast cancer (TNBC) patients in South Korea. MATERIALS AND METHODS: We retrospectively reviewed 699 patients with TNBC who underwent PORT at six institutions between 2008 and 2010. The median follow-up period was 94 months (range: 7-192 months). There were 216, 380, and 100 patients in stages I, II, and III, respectively. RESULTS: After 94 months post-treatment, all patients with pathologic complete remission after neoadjuvant chemotherapy were alive without any failure. Distant metastasis was the main cause of failure. The 5-year overall survival rate was 91.4%, 5-year loco-regional relapse-free survival rate (LRRFS) was 92.3%, 5-year distant metastasis-free survival rate (DMFS) was 89.4%, and 5-year disease-free survival rate (DFS) was 85.2%. On multivariate (Cox) analysis, T and N stages were significant prognostic factors for survival, and lympho-vascular invasion (LVI) was a significant factor for LRRFS and DMFS. Ki-67 expression was significantly associated with LRRFS and DFS. CONCLUSION: We verified that T and N stages, LVI, and Ki-67 expression were significantly associated with survival outcomes after PORT in TNBC.

Current Utilization and Research Status of Herbal Medicine Sipjeondaebotang for Anemia: A Scoping Review.

BACKGROUND/OBJECTIVES: Anemia is a global health issue affecting diverse populations, particularly older adults, and conventional treatments often show limited efficacy. This study aimed to evaluate the utilization and effectiveness of Sipjeondaebotang (SDT), a prescription drug used in traditional East Asian medicine, in treating various types of anemia. METHODS: A scoping review was conducted following Arksey and O'Malley's framework and PRISMA-ScR guidelines. Six electronic databases were searched for clinical studies on SDT, while focusing on human participants and excluding animal and cellular studies. Sixteen studies, including nine randomized controlled trials, two controlled clinical trials, two case series, and three case reports, involving 863 participants, were analyzed. These studies were primarily conducted in China, Korea, and Japan. RESULTS: According to the analysis, SDT improved hemoglobin levels across all types of anemia studied, with all controlled studies showing significant improvements compared with the control groups. Additionally, SDT reduced blood loss, improved recovery times, and decreased transfusion requirements in patients with post-operative anemia, with lower adverse event rates than those in the control groups. These findings suggest that SDT may enhance hematological parameters and improve overall patient outcomes. CONCLUSIONS: In conclusion, SDT may be an effective treatment for anemia that improves hemoglobin levels and patient outcomes. However, further high-quality, large-scale studies are necessary to standardize SDT prescriptions, confirm the optimal treatment duration, and validate its efficacy and safety across different anemia types.

N121T and N121S substitutions on the SARS-CoV-2 spike protein impact on serum neutralization.

The N121 site on the spike protein of SARS-CoV-2 is associated with heme and its metabolite, biliverdin, which can affect antibody binding. Both N121T and N121S substitutions have been observed in natural conditions and in a hamster model of dual infection with SARS-CoV-2 and Influenza A virus. Serum pseudotype neutralization assays against HIV-1 particles carrying wild-type, N121T, and N121S spikes with immune mouse and human sera revealed that N121T and N121S mutations had a greater impact on serum neutralization than biliverdin treatment. Although N121T and N121S substitutions are not currently major SARS-CoV-2 variants of concern, this study could provide fundamental information to prepare for potential future mutations at the N121 site of SARS-CoV-2.

A humanized ACE2 mouse model recapitulating age- and sex-dependent immunopathogenesis of COVID-19.

In the ongoing battle against coronavirus disease 2019 (COVID-19), understanding its pathogenesis and developing effective treatments remain critical challenges. The creation of animal models that closely replicate human infection stands as a critical step forward in this research. Here, we present a genetically engineered mouse model with specifically-humanized knock-in ACE2 (hiACE2) receptors. This model, featuring nine specific amino acid substitutions for enhanced interaction with the viral spike protein, enables efficient severe acute respiratory syndrome coronavirus 2 replication in respiratory organs without detectable infection in the central nervous system. Moreover, it mirrors the age- and sex-specific patterns of morbidity and mortality, as well as the immunopathological features observed in human COVID-19 cases. Our findings further demonstrate that the depletion of eosinophils significantly reduces morbidity and mortality, depending on the infecting viral dose and the sex of the host. This reduction is potentially achieved by decreasing the pathogenic contribution of eosinophil-mediated inflammation, which is strongly correlated with neutrophil activity in human patients. This underscores the model's utility in studying the immunopathological aspects of COVID-19 and represents a significant advancement in COVID-19 modeling. It offers a valuable tool for testing vaccines and therapeutics, enhancing our understanding of the disease mechanisms and potentially guiding more targeted and effective treatments.

Anti-inflammatory Effect of Symplocos prunifolia Extract in an In Vitro Model of Acute Pneumonia.

Acute pneumonia is a respiratory disease characterized by inflammation within the lung tissue, exhibiting higher morbidity rates and mortality rates among immunocompromised children and older adults. Symplocos species have been traditionally used as herbal remedies for conditions like dysentery, skin ulcers, diarrhea, and dyspepsia. Contemporary research has employed various Symplocos species in the study of diverse diseases. However, the exact efficacy and mechanisms of action of Symplocos Prunifolia remain unknown. Therefore, this study investigated the anti-inflammatory mechanism of S. prunifolia extract (SPE) in A549 and RAW264.7 cells stimulated by lipopolysaccharide (LPS). SPE significantly reduced nitric oxide (NO) production and the protein expression levels of like inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 cells. Furthermore, it reduced the protein expression levels of iNOS, COX-2 and the levels of pro-inflammatory cytokines in LPS-stimulated A549 cells. The mechanism underlying the anti-inflammatory effect of SPE was associated with the inhibition of LPS stimulated the phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) and Mitogen-activated protein kinase (MAPK) phosphorylation. Moreover, we confirmed that SPE decreased the nuclear translocation of nuclear factor-κB (NF-κB)/p65 stimulated by LPS. In conclusion, these results demonstrate that SPE alleviates inflammatory responses by deactivating the PI3K/Akt, MAPK, and NF-κB signaling pathways. Our findings suggest that SPE is a potential candidate for acute pneumonia prevention.

A machine learning model to predict liver-related outcomes after the functional cure of chronic hepatitis B.

BACKGROUND & AIMS: The risk of hepatocellular carcinoma (HCC) and hepatic decompensation persists after hepatitis B surface antigen (HBsAg) seroclearance. This study aimed to develop and validate a machine learning model to predict the risk of liver-related outcomes (LROs) following HBsAg seroclearance. METHODS: A total of 4,787 consecutive patients who achieved HBsAg seroclearance between 2000 and 2022 were enrolled from 6 centers in South Korea and a territory-wide database in Hong Kong, comprising the training (n=944), internal validation (n=1,102), and external validation (n=2,741) cohorts. Three machine learning-based models were developed and compared in each cohort. The primary outcome was the development of any LRO, including HCC, decompensation, and liver-related death. RESULTS: During a median follow-up of 55.2 (interquartile range=30.1-92.3) months, 123 LROs were confirmed (1.1%/person-year) in the Korean cohort. A model with the best predictive performance in the training cohort was selected as the final model (designated as PLAN-B-CURE), which was constructed using a gradient boosting algorithm and 7 variables (age, sex, diabetes, alcohol consumption, cirrhosis, albumin, and platelet count). Compared to previous HCC prediction models, PLAN-B-CURE showed significantly superior accuracy in the training cohort (c-index: 0.82 vs. 0.63-0.70, all P<0.001; area under the receiver operating characteristic curve: 0.86 vs. 0.62-0.72, all P<0.01; area under the precision-recall curve: 0.53 vs. 0.13-0.29, all P<0.01). PLAN-B-CURE showed a reliable calibration function (Hosmer-Lemeshow test P>0.05) and these results were reproduced in the internal and external validation cohorts. CONCLUSION: This novel machine learning model consisting of 7 variables provides reliable risk prediction of LRO after HBsAg seroclearance that can be used for personalized surveillance.

Prognosis prediction and immunotherapy optimisation for cryptogenic new-onset refractory status epilepticus.

BACKGROUND: Cryptogenic new-onset refractory status epilepticus (cNORSE) currently lacks comprehensive knowledge regarding its clinical dynamics, prognostic factors and treatment guidance. Here we present the longitudinal clinical profiles, predictive factors for outcomes and the optimal duration of immunotherapy in patients with cNORSE. METHODS: This retrospective secondary endpoint analysis investigated patients with cNORSE identified from a prospective autoimmune encephalitis cohort at a national referral centre in Korea. The main outcomes included longitudinal functional scales, seizure frequency and the number of antiseizure medications. Measures encompassed NORSE-related clinical parameters such as the duration of unconsciousness, immunotherapy profiles, cytokine/chemokine analysis, and serial MRI scans. RESULTS: A total of 74 patients with cNORSE were finally analysed (mean age: 38.0±18.2; 36 (48.6%) male). All patients received first-line immunotherapy, and 91.9% (68/74) received second-line immunotherapy. A total of 83.8% (62/74) regained consciousness within a median duration of 30 days (14-56), and 50% (31/62) achieved good outcome (mRS ≤2) at 2 years. Poor 1-year outcomes (mRS ≥3) were predicted by the presence of mesial temporal lobe (mTL) and extra-mTL lesions at 3-month MRI, and prolonged unconsciousness (≥60 days). Those with mTL atrophy exhibited a higher seizure burden post-NORSE. The optimal duration of immunotherapy appeared to be between 18 weeks and 1-year post-NORSE onset. CONCLUSIONS: This study elucidates longitudinal clinical dynamics, functional outcomes, prognostic factors and immunotherapy response in patients with cNORSE. These findings might contribute to a more standardised understanding and clinical decision-making for cNORSE.

TOR2 plays the central role in rapamycin-induced lifespan extension in budding yeast.

The target of rapamycin (TOR) protein, renowned for its highly conserved nature across species, plays a pivotal role in modulating signaling pathways via its multiprotein complexes, TORC1 and TORC2. The relationship between TOR and its inhibitor, rapamycin, especially in the context of lifespan extension, has earned significant attention. Unlike mammals, which have a single TOR gene, the budding yeast Saccharomyces cerevisiae features two TOR paralogs: TOR1 and TOR2. Non-essential TOR1 gene has been the focus of extensive research, whereas the essential TOR2 gene has received relatively little attention in lifespan studies. In our research, we engineered a point mutation (Ser-1975-Ile) within the FKBP12-rapamycin-binding (FRB) domain of Tor2p to block rapamycin binding. Remarkably, this mutation negated the lifespan-extending benefits of rapamycin, irrespective of the TOR1 gene status. Our findings indicate that the TOR2 gene likely serves as the primary mammalian ortholog, playing a crucial role in mediating the effects of rapamycin on lifespan extension. This discovery opens a new avenue for the development of innovative anti-aging agents targeting the TOR. complex.

Innovative and versatile surface-enhanced Raman spectroscopy-inspired approaches for viral detection leading to clinical applications: A review.

The evolution of analytical techniques has opened the possibilities of accurate analyte detection through a straightforward method and short acquisition time, leading towards their applicability to identify medical conditions. Surface-enhanced Raman spectroscopy (SERS) has long been proven effective for rapid detection and relies on SERS spectra that are unique to each specific analyte. However, the complexity of viruses poses challenges to SERS and hinders further progress in its practical applications. The principle of SERS revolves around the interaction among substrate, analyte, and Raman laser, but most studies only emphasize the substrate, especially label-free methods, and the synergy among these factors is often ignored. Therefore, issues related to reproducibility and consistency of results, which are crucial for medical diagnosis and are the main highlights of this review, can be understood and largely addressed when considering these interactions. Viruses are composed of multiple surface components and can be detected by label-free SERS, but the presence of non-target molecules in clinical samples interferes with the detection process. Appropriate spectral data processing workflow also plays an important role in the interpretation of results. Furthermore, integrating machine learning into data processing can account for changes brought about by the presence of non-target molecules when analyzing spectral features to accurately group the data, for example, whether the sample corresponds to a positive or negative patient, and whether a virus variant or multiple viruses are present in the sample. Subsequently, advances in interdisciplinary fields can bring SERS closer to practical applications.

Acute Emotional Impact of Peer Suicide and Student-Related Factors.

OBJECTIVE: This study explored the negative emotional impact of peer suicide on adolescent students during the early stages of becoming aware of suicide and examined the adverse effects of related environmental and mental health factors. METHODS: This study was conducted from March 1, 2020 to December 31, 2021, targeting students enrolled in middle and high schools where student suicide occurred. Emotional impact was assessed using the Korean version of the Impact of Event Scale-Revised (IES-R-K), State-Trait Anxiety Inventory-X, Center for Epidemiologic Studies-Depression Scale (CES-D), and Beck's Scale for Suicide Ideation (SSI). χ2 test and Pearson's correlation analysis were performed to analyze subgroup differences and explore relationships between scale scores, respectively. RESULTS: Of the 2,382 participants, 25.1% belonged to the post-traumatic stress disorder (PTSD) or PTSD tendency group on the IES-R-K, and 22.2% showed abnormalities in the State-Trait Anxiety Inventory-State. Students in the same class as the deceased student and those in the same grade but in different classes had higher risk rates than those in different grades. Boarding school students had 1.9 times higher odds of experiencing emotional impacts than non-boarding students. On the CES-D, 10.4% of the students showed potential depression, with 3.7 times higher odds of experiencing emotional impact than those with normal scores. Moreover, 4.5% of the students reported suicidal ideation on the SSI, with those experiencing mild suicidal ideation having 1.9 times higher odds of experiencing emotional impact than those with normal scores. CONCLUSION: A significant proportion of students experienced negative impacts of peer suicide. Students in close-knit environments, such as the same class, grade, and boarding school as the deceased, or those with depression or anxiety experienced a more pronounced negative impact.