The 5-hydroxytryptamine type3 (5-HT3 ) receptor, a ligand-gated ion channel, plays a critical role in synaptic transmission. It has been implicated in various neuropsychiatric disorders. This study aimed to elucidate the mechanism by which quetiapine, an atypical antipsychotic, could inhibit 5-HT3 receptor-mediated currents in NCB20 neuroblastoma cells. Whole-cell patch-clamp recordings were used to study effects of quetiapine on receptor ion channel kinetics and its competitive antagonism. Co-application of quetiapine shifted 5-HT concentration-response curve rightward, significantly increasing the EC50 without altering the maximal response (Emax ), suggesting a competitive inhibition. Quetiapine's IC50 varied with 5-HT concentration and treatment condition. The IC50 value of quetiapine was 0.58 μM with 3μM 5-HT and 25.23 μM with 10 μM 5-HT, indicating an inverse relationship between quetiapine efficacy and agonist concentration. Pretreatment of quetiapine significantly enhanced its inhibitory potency, reducing its IC50 from 25.23 μM to 0.20 μM.Interaction kinetics experiments revealed an IC50 of 5.17 μM for an open state of the 5-HT3 receptor, suggesting weaker affinity during receptor activation. Quetiapine also accelerated receptor deactivation and desensitization, suggesting that it could stabilize the receptor in non-conducting states. Additionally, quetiapine significantly prolonged recovery from desensitization without affecting recovery from deactivation, demonstrating its selective impact on receptor kinetics. Inhibition of the 5-HT3 receptor by quetiapine was voltage-independent, and quetiapine exhibited no usedependency, further supporting its role as a competitive antagonist. These findings provide insights into inhibitory mechanism of quetiapine on 5-HT3 receptor and suggest its potential therapeutic implications for modulating serotonergic pathways in neuropsychiatric disorders.

Haloperidol is a typical antipsychotic drug effective in alleviating positive symptoms of schizophrenia by blocking dopamine receptor 2 (DR2). However, it is also known to produce neuropsychiatric effects by acting on various targets other than DR. In this study, we investigated effect of haloperidol on function of 5-hydroxytryptamine (5-HT) 3 receptor, a ligand-gated ion channel belonging to the serotonin receptor family using the whole-cell voltage clamp technique and NCB20 neuroblastoma cells. When co-applied with 5-HT, haloperidol inhibited 5-HT3 receptormediated currents in a concentration-dependent manner. A reduction in maximal effect (E max ) and an increase in EC 50 observed during co-application indicated that haloperidol could act as a non-competitive antagonist of 5-HT3 receptors. Haloperidol inhibited the activation of 5-HT3 receptor, while also accelerating their deactivation and desensitization. The inhibitory effect of haloperidol showed no significant difference between pre- and co-application. Haloperidol did not alter the reversal potential of 5-HT3 receptor currents. Furthermore, haloperidol did not affect recovery from deactivation or desensitization of 5-HT3 receptors. It did not show a use-dependent inhibition either. These findings suggest that haloperidol can exert its inhibitory effect on 5-HT3 receptors by allosterically preventing opening of ion channels. This mechanistic insight enhances our understanding of relationships between 5-HT3 receptors and pharmacological actions of antipsychotics.

Background: This study evaluated adherence to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) and Korean guidelines in the prescription patterns of respiratory specialists for stable chronic obstructive pulmonary disease (COPD) management. Methods: Data were collected on medications from 2011 to 2022 using the Korea COPD Subtype Study (KOCOSS) cohort. Patients were divided into two groups: those registered before and after 2019, and we analyzed the percentage of patients meeting the recommended treatment criteria established by each guideline. Results: Among 3,477 patients, 85.6% received pharmacological therapy, and 81.6% utilized inhaled medications. Compared to patients enrolled before 2019, there was an increase in inhaler prescriptions among those registered after 2019 (79.7% vs. 86.7%), with dual bronchodilators being the predominant therapy prescribed. Of the patients receiving treatment, 56.9% adhered to the Korean 2018 guideline. Compliance with the GOLD 2019 and GOLD 2023 guidelines was observed in 31.3% and 28.0% of cases, respectively. When analyzing inhaler prescription patterns according to both subgroups and considering the Korean 2018, GOLD 2019, and GOLD 2023 guidelines concurrently, the adherence rates were as follows: (56.6%, 37.8%, 24.0%) and (57.7%, 14.0%, 38.6%). Conclusion Adherence rates were higher for the Korean guideline compared to the GOLD recommendations. Furthermore, alignment with both the Korean 2018 and GOLD 2023 guidelines increased among patients enrolled after 2019, compared to those registered earlier. These findings suggest that physicians are modifying their therapeutic strategies to align with both domestic and recent international guidelines.

Background: This study aimed to identify the clinical characteristics of multidrug-resistant/ rifampicin-resistant tuberculosis (MDR/RR-TB) in the Republic of Korea. Methods: Data of notified people with tuberculosis between July 2018 and December 2021 were retrieved from the Korea Tuberculosis Cohort database. MDR/RR-TB was further categorized according to isoniazid susceptibility as follows: multidrug-resistant tuberculosis (MDR-TB), rifampicin-monoresistant tuberculosis (RMR-TB), and RR-TB if susceptibility to isoniazid was unknown. Multivariable logistic regression analysis was conducted to identify the factors associated with MDR/RR-TB. Results: Between 2018 and 2021, the proportion of MDR/RR-TB cases among all TB cases and TB cases with known drug susceptibility test results was 2.1% (502/24,447). The proportions of MDR/RR-TB and MDR-TB cases among TB cases with known drug susceptibility test results were 3.3% (502/15,071) and 1.9% (292/15,071), respectively. Among all cases of rifampicin resistance, 31.7% (159/502) were RMR-TB and 10.2% (51/502) were RR-TB. Multivariable logistic regression analyses revealed that younger age, foreigners, and prior tuberculosis history were significantly associated with MDR/ RR-TB. Conclusion Rapid identification of rifampicin resistance targeting the high-risk populations, such as younger generations, foreign-born individuals, and previously treated patients are necessary for patient-centered care.

Purpose: Emphysematous pyelonephritis (EPN) is a life-threatening disease requiring immediate treatment. This multicenter retrospective cohort study aimed to analyze the mortality rate and risk factors associated with EPN. Materials and Methods: Between January 2011 and February 2021, 217 patients diagnosed with EPN via computed tomography who visited 14 teaching hospitals were retrospectively analyzed. Clinical data, including age, sex, comorbidities, Huang and Tseng classification, hydronephrosis, acute kidney injury, blood and urine tests, surgical interventions, percutaneous drainage, and conservative treatments, were compared between the survival and death groups. Risk factors for mortality due to EPN were analyzed using univariate and multivariate methods. Results: The mean age of survivors and deceased patients was 67.8 and 69.0 years, respectively (p=0.136). The sex distribution (male/female) was 48/146 and 8/15, respectively (p=0.298). Of the 217 patients, 23 died, resulting in a mortality rate of 10.6%. In univariate analysis, the Huang and Tseng classification (p=0.004), platelet count (p=0.005), and acute kidney injury (p=0.007) were significantly associated with mortality from EPN. In multivariate analysis, only the Huang and Tseng classification (p=0.029) was identified as a risk factor. Mortality rates according to the Huang and Tseng classification were as follows: class I (5.88%), class II (7.50%), class IIIa (14.28%), class IIIb (25.00%), and class IV (23.07%). Conclusions EPN is associated with a high mortality rate. Among various clinical factors, the Huang and Tseng classification was the most significant indicator for predicting mortality.

Purpose: Adjuvant treatment for craniopharyngioma after surgery is controversial. Adjuvant external beam radiation therapy (EBRT) can increase the risk of long-term sequelae. Stereotactic radiosurgery (SRS) is used to reduce treatment-related toxicity.In this study, we compared the treatment outcomes and toxicities of adjuvant therapies for craniopharyngioma. Materials and Methods: We analyzed patients who underwent craniopharyngioma tumor removal between 2000 and 2017. Of the 153 patients, 27 and 20 received adjuvant fractionated EBRT and SRS, respectively. We compared the local control (LC), progression-free survival (PFS), and overall survival between groups that received adjuvant fractionated EBRT, SRS, and surveillance. Results: The median follow-up period was 77.7 months. For SRS and surveillance, the 10-year LC was 57.2% and 57.4%, respectively. No local progression was observed after adjuvant fractionated EBRT. One patient in the adjuvant fractionated EBRT group died owing to glioma 94 months after receiving radiotherapy (10-year PFS: 80%). The 10-year PFS was 43.6% and 50.7% in the SRS and surveillance groups, respectively. The treatment outcomes significantly differed according to adjuvant treatment in nongross total resection (GTR) patients. Additional treatment-related toxicity was comparable in the adjuvant fractionated EBRT and other groups. Conclusion Adjuvant fractionated EBRT could be effective in controlling local failure, especially in patients with non-GTR, while maintaining acceptable treatment-related toxicity.

Background and Objectives: Pediatric chronic rhinosinusitis (CRS) significantly affects children’s quality of life and learning abilities. This study aimed to evaluate the postoperative outcomes in pediatric patients who underwent functional endoscopic sinus surgery (FESS) for CRS. Methods: A retrospective review was conducted on pediatric patients who underwent FESS for CRS at 11 university hospitals. The inclusion criteria were patients under 20 years old with bilateral disease who were operated on between January 2005 and December 2021. The data collected included demographics, clinical history, blood tests, preoperative computed tomography, and preoperative and postoperative symptom control. The Kruskal-Wallis and Fisher exact tests were used to compare the quantitative and qualitative data, respectively. Results: In total, 213 patients were enrolled. The mean age was 13.4±3.0 years, and 145 (68.1%) were male. One hundred sixty-four patients (77.0%) had nasal polyps and 33 patients (15.5%) underwent revision FESS. The preoperative symptoms, in order of prevalence, included nasal obstruction (87.8%), rhinorrhea (71.8%), a sense of postnasal drip (58.2%), hyposmia (44.6%), cough (24.4%), and facial fullness (18.3%). These symptoms were significantly alleviated for up to 3 years after surgery (p<0.001). At the time of the last follow-up, 121 patients (56.8%) were controlled, 80 (37.6%) were partly controlled, and 12 (5.6%) were uncontrolled. Patients in the uncontrolled group had higher Lund-Mackay scores, longer follow-up durations, and more instances of revision surgery compared to those in the controlled and partly controlled groups. When age was categorized into three groups, those aged 16 years or older tended to have lower Lund-Mackay scores and better control. Conclusion FESS significantly improves both the postoperative symptoms and the long-term quality of life in pediatric CRS patients. Better symptom control is associated with older age and a lower disease burden.

Purpose: To investigate the outcomes of brolucizumab reinjection after intraocular inflammation (IOI) development. Methods: This retrospective study analyzed patients with brolucizumab injections from April 2021 to January 2024. Patients who developed IOI after brolucizumab were included and categorized into subgroups depending on reinjection, discontinuation, and further IOI development. Results: A total of 472 eyes of 432 patients received brolucizumab injections. Thirty-eight cases developed IOI at least once, and 25 continued brolucizumab. Sixteen cases had no more IOI events, and nine experienced a second or more IOI events. Among the nine cases, three maintained brolucizumab injections despite IOI recurrence. The incidence of IOI was 8.1% based on the number of eyes (38 of 472 eyes) and 2.0% based on the number of brolucizumab injections (50 of 2,468 injections). The incidence of occlusive retinal vasculitis was 0.2% (1 of 472 eyes). The recurrence rate was 23.7% (9 of 38 eyes). The average number of injections between the first brolucizumab injection and the injection date on which IOI first developed was 2.15 times in the no-reinjection group, 3.44 times in the no-IOI-recurrence group, and 2.0 times in the second-IOI-episode group. Time to IOI occurrence in cases with first IOI episode was 18.60 ± 16.73 days, with 15 cases developing IOI within 1 week. Conclusions This study elucidates the real-world incidence of brolucizumab associated IOIs, with a description of information related to reinjections after the IOI episodes. A comprehensive understanding of brolucizumab reinjection is essential for its optimal utilization.

Radiofrequency ablation (RFA) is a minimally invasive treatment modality used as an alternative to surgery in patients with benign thyroid nodules, recurrent thyroid cancers (RTCs), and primary thyroid microcarcinomas. The Korean Society of Thyroid Radiology (KSThR) initially developed recommendations for the optimal use of RFA for thyroid tumors in 2009 and revised them in 2012 and 2017. As new meaningful evidence has accumulated since 2017 and in response to a growing global interest in the use of RFA for treating malignant thyroid lesions, the task force committee members of the KSThR decided to update the guidelines on the use of RFA for the management of RTCs based on a comprehensive analysis of current literature and expert consensus.

Objective: To assess the performance of novel qualitative diagnostic criteria using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) to identify the pathologic complete response (pCR) of primary tumors in esophageal cancer after neoadjuvant chemoradiation (nCRT). Materials and Methods: Patients who underwent nCRT, subsequent MRI, positron emission tomography/computed tomography (PET/CT), endoscopy, or esophagectomy for esophageal cancer between October 2021 and October 2023 were retrospectively analyzed. The DCE-MRI response of primary tumors was interpreted using five grades by thoracic radiologists as follows: G1 (compatible with CR), G2 (probable CR), G3 (probable partial response [PR]), G4 (compatible with PR), and G5 (stable or progressive disease). The performances of MRI, PET/CT, endoscopy, and their combinations in diagnosing pCR in primary tumors were calculated. Results: A total of 52 patients (male:female, 46:6; age, 61.2 ± 8.0 years) were included. Surgical specimens revealed pCR (ypT0) in 34 patients. G1 as the MRI criterion for pCR of primary tumors yielded a positive predictive value (PPV), specificity of 100% (18/18), and low sensitivity (23.5% [8/34]). Combining G1 and G2 as the MRI criteria increased the sensitivity to 73.5% (25/34), with a specificity of 88.9% (16/18), accuracy of 78.8% (41/52), and PPV of 92.6% (25/27). Adding the DCEMRI results (G1-2) significantly improved accuracy for both PET/CT (from 65.4% [34/52] to 80.8% [42/52], P = 0.03) and endoscopy (from 55.8% [29/52] to 76.9% [40/52], P = 0.005), with increase in sensitivity (from 55.9% [19/34] to 82.4% [28/34] for PET/CT-based evaluation [P = 0.008] and from 47.1% [16/34] to 82.4% [28/34] for endoscopy-based evaluation [P = 0.001]). Conclusion DCE-MRI-based grading shows high diagnostic performance for identifying pCR in primary tumors, particularly in terms of PPV and specificity, and enhances response evaluation when combined with PET/CT and endoscopy.