Auricular vagus nerve stimulation (aVNS) is one of the promising neuromodulation techniques due to its non-invasiveness, convenience, and effectiveness. aVNS has been suggested as a potential treatment for neurodegenerative diseases showing impaired cerebrospinal fluid (CSF) dynamics. Improving CSF flow has been proposed as a key mechanism of the therapeutic effect on neurodegenerative diseases. However, aVNS parameters have been set empirically and the effective parameter that maximize the effect remains elusive. Here we show that 30 minutes of low-frequency aVNS increased arterial vasomotion events and enhanced cortical CSF influx along the branches of middle cerebral arteries. By using in vivo two photon imaging or widefield fluorescence microscopy with plasma and CSF tracers for visualizing blood vessels and perivascular spaces, arterial vasomotion and cortical CSF influx dynamics were acquired. The low-frequency (2 Hz) aVNS, but not middleand high-frequency (40 and 100 Hz) aVNS, significantly increased the number of vasomotion events compared to the sham group. Accordingly, in the CSF imaging, 2 Hz of aVNS markedly enhanced the CSF influx. Our findings demonstrate that lowfrequency aVNS is the effective parameter in respect to modulating vasomotion and CSF influx, resulting in brain clearance effect.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Spontaneous coronary artery dissection (SCAD) is a condition in which an intramural hematoma within the coronary artery leads to acute coronary syndrome without atherosclerosis, trauma, or iatrogenic causes. It predominantly affects middle-aged women and is associated with several predisposing conditions, including fibromuscular dysplasia, systemic inflammatory disorders, connective tissue diseases, and coronary artery spasms. We report the case of a 64-year-old male with a history of hypertension who died of SCAD. His death occurred suddenly and without preceding trauma while the decedent was working overtime at a construction site. On gross examination, a thrombus-like material was identified in a branch of the left anterior descending artery and was initially presumed to be a postmortem clot. However, microscopic examination revealed an intramural hemorrhage, medial dissection, and formation of a false lumen within the coronary artery. This case report highlights the importance of a thorough histopathological examination of the coronary arteries during autopsy, even in the absence of atherosclerosis.

Objective: To evaluate the safety and efficacy of coil embolization of venous segments in patients with Type IIa pelvic arteriovenous malformations (AVMs). Materials and Methods: A retrospective study was performed on 13 patients (median age, 43 years, range 20–62 years, 7 males) who underwent transvenous coil embolization for Type IIa pelvic AVM (characterized by multiple arterioles shunting to focal venous segments of a single draining vein) without the use of additional liquid embolic agents from March 2017 to February 2023. Treatment outcomes were analyzed based on clinical evaluations, post angiography findings, and follow-up CT. Results: Fourteen procedures were performed on 13 patients. Except in one patient, all treatments were completed in a single session. Transvenous access was employed in 10 procedures, whereas direct puncture was used in four sessions. The embolization procedures used an average of 55.7 ± 58.5 coils (range, 7–238) and lasted an average of 127.3 ± 39.5 minutes.The technical success rate was 92.9% (of 13/14). All patients reported symptom improvement. Follow-up CT scans showed complete occlusion of the AVM without recurrence in ten of the 13 patients. There was one minor adverse event: a small retroperitoneal hemorrhage, likely related to direct puncture, which resolved spontaneously. No other adverse events were observed. Conclusion Coil embolization of the draining vein segment, without the use of additional liquid embolic agents is a safe and effective method for managing Type IIa pelvic AVM.

Objective: Previous studies have reported an association between cancer-related symptoms and perceived social support (PSS). The objective of this study was to analyze whether Chemotherapy-Induced Peripheral Neuropathy (CIPN), a prevalent side effect of chemotherapy, varies according to PSS level using a validated tool for CIPN at prospective follow-up. Methods: A total of 39 breast cancer patients were evaluated for PSS using the Multidimensional Scale of Perceived Social Support (MSPSS) prior to chemotherapy and were subsequently grouped into one of two categories for each subscale: low-to-moderate PSS and high PSS. CIPN was prospectively evaluated using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy 20 (CIPN20) at five time points. A linear mixed-effects model with square root transformation was employed to investigate whether the CIPN20 scales varied by PSS level and time point. Results: Statistical analysis of the MSPSS total scale and subscales revealed a significant effect of the friends subscale group and time point on the CIPN20 sensory scale. The sensory scale score of CIPN20 was found to be lower in participants with high PSS from friends in comparison to those with low-to-moderate PSS at 1 month post-chemotherapy (p=0.010). Conclusion This is the first study to prospectively follow the long-term effect of pre-treatment PSS from friends on CIPN. Further studies based on larger samples are required to analyze the effects of PSS on the pathophysiology of CIPN.

Auricular vagus nerve stimulation (aVNS) is one of the promising neuromodulation techniques due to its non-invasiveness, convenience, and effectiveness. aVNS has been suggested as a potential treatment for neurodegenerative diseases showing impaired cerebrospinal fluid (CSF) dynamics. Improving CSF flow has been proposed as a key mechanism of the therapeutic effect on neurodegenerative diseases. However, aVNS parameters have been set empirically and the effective parameter that maximize the effect remains elusive. Here we show that 30 minutes of low-frequency aVNS increased arterial vasomotion events and enhanced cortical CSF influx along the branches of middle cerebral arteries. By using in vivo two photon imaging or widefield fluorescence microscopy with plasma and CSF tracers for visualizing blood vessels and perivascular spaces, arterial vasomotion and cortical CSF influx dynamics were acquired. The low-frequency (2 Hz) aVNS, but not middleand high-frequency (40 and 100 Hz) aVNS, significantly increased the number of vasomotion events compared to the sham group. Accordingly, in the CSF imaging, 2 Hz of aVNS markedly enhanced the CSF influx. Our findings demonstrate that lowfrequency aVNS is the effective parameter in respect to modulating vasomotion and CSF influx, resulting in brain clearance effect.

Background: Respiratory infections play a major role in acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This study assessed the prevalence of bacterial and viral pathogens and their clinical impact on patients with AECOPD. Methods: This retrospective study included 1,186 patients diagnosed with AECOPD at 28 hospitals in South Korea between 2015 and 2018. We evaluated the identification rates of pathogens, basic patient characteristics, clinical features, and the factors associated with infections by potentially drug-resistant (PDR) pathogens using various microbiological tests. Results: Bacteria, viruses, and both were detected in 262 (22.1%), 265 (22.5%), and 129 (10.9%) of patients, respectively. The most common pathogens included Pseudomonas aeruginosa (17.8%), Mycoplasma pneumoniae (11.2%), Streptococcus pneumoniae (9.0%), influenza A virus (19.0%), rhinovirus (15.8%), and respiratory syncytial virus (6.4%). Notably, a history of pulmonary tuberculosis (odds ratio [OR], 1.66; p=0.046), bronchiectasis (OR, 1.99; p=0.032), and the use of a triple inhaler regimen within the past 6 months (OR, 2.04; p=0.005) were identified as significant factors associated with infection by PDR pathogens. Moreover, patients infected with PDR pathogens exhibited extended hospital stays (15.9 days vs. 12.4 days, p=0.018) and higher intensive care unit admission rates (15.9% vs. 9.5%, p=0.030). Conclusion This study demonstrates that a variety of pathogens are involved in episodes of AECOPD. Nevertheless, additional research is required to confirm their role in the onset and progression of AECOPD.

Background: Computed tomography (CT) scans are utilized to assess emphysema, a prominent phenotype of chronic obstructive pulmonary disease (COPD). Variability in CT protocols and equipment across hospitals can impact accuracy. This study aims to implement kernel conversion across different CT settings and evaluate changes in the correlation between the emphysema index pre- and post-kernel conversion, along with clinical measures in COPD patients. Methods: Data were extracted from the Korea COPD Subgroup Study database, which included CT scan images from 484 COPD patients. These images underwent kernel conversion. Emphysema extent was quantified using the percentage of low-attenuation areas (%LAA-950) determined by a deep learning-based program. The correlation between %LAA-950 and clinical parameters, including lung function tests, the modified Medical Research Council (mMRC), 6-minute walking distance (6MWD), COPD assessment test (CAT), and the St. George’s Respiratory Questionnaire for COPD (SGRQ-c), was analyzed. Subsequently, these values were compared across various CT settings. Results: A total of 484 participants were included. Kernel conversion significantly reduced the variance in %LAA-950 values (before vs. after: 12.6±11.0 vs. 8.8±11.9). Post-kernel conversion, %LAA-950 demonstrated moderate correlations with forced expiratory volume in 1 second (r=–0.41), residual volume/total lung capacity (r=0.42), mMRC (r=0.25), CAT score (r=0.12), SGRQ-c (r=0.21), and 6MWD (r=0.15), all of which were improved compared to the unconverted dataset (all p<0.01). Conclusion CT images processed through kernel conversion enhance the correlation between the extent of emphysema and clinical parameters in COPD.

Background/Aims: Although the association between the use of proton pump inhibitors (PPIs) and the risk of gastric cancer has been postulated in casecontrol and cohort studies, it remains still controversial. We aim to evaluate association of PPI use with gastric cancer in regions with high prevalence of gastric cancer, particularly in patients who underwent eradication of Helicobacter pylori, by systemic review and meta-analysis. Methods: Comprehensive literature search through the PubMed, Embase, and Cochrane database was performed in October 2023. We used random effects model to calculate pooled odds ratios (ORs) with 95% confidence intervals (CIs) between PPI use and gastric cancer.The Cochran Q-statistic and the I² test were employed for evaluating potential heterogeneity between studies. Results: Two case-control and 6 cohort studies were identified. PPI use was significantly associated with the development of gastric cancer (OR, 2.02; 95% CI, 1.35-3.01). In subgroup analysis carried out according to the study design, sample size, and adjustment of confounding factors (age, sex, and H. pylori), such association was significant. A meta-analysis of 4 studies performed in patients with H. pylori eradication history showed that the use of PPIs was significantly associated with an elevated incidence of gastric cancer (OR, 2.10; 95% CI, 1.48-2.97). Conclusions Long-term use of PPIs is associated with an increased risk of gastric cancer in Asian regions with high prevalence of gastric cancer, particularly in subjects who have eradication history of H. pylori. Optimization of long-term PPI use seems to be necessary in regions where gastric cancer is prevalent.

Background/Aims: Serum gastrin levels may be elevated following proton pump inhibitor (PPI) therapy. We aim to elucidate the predictors for the development of hypergastrinemia in maintenance treatment for mild gastroesophageal reflux disease (GERD) using a half-dose PPI. Methods: This study analyzed data from a prospective randomized trial to compare continuous versus on-demand maintenance treatment modalities in patients with mild GERD. Age, sex, body mass index, Helicobacter pylori infection, serum gastrin levels, pepsinogen (PG) I/II ratios, total days of PPI intake, and weight-based PPI dosage (mg/kg) were evaluated. Results: Data from 293 patients who completed a randomized trial were analyzed (continuous group, n = 147 vs on-demand group, n = 146). In univariate analysis, age (P < 0.001), H. pylori infection (P = 0.012), baseline gastrin levels (P < 0.001), and baseline PG ratios (P = 0.016) significantly correlated with post-treatment gastrin levels. In multivariate analysis, age, baseline gastrin levels, and baseline PG ratios were independently associated with final serum gastrin levels. In univariate analysis, age (P = 0.018), H. pylori infection (P = 0.028), baseline gastrin levels (P = 0.011), and baseline PG ratios (P = 0.031) significantly correlated with the development of hypergastrinemia. In multivariate analysis, age, baseline gastrin levels, and baseline PG ratios were independently associated with the development of hypergastrinemia. Conclusion Old age, high baseline serum gastrin levels, and low baseline PG ratios are significant predictors of the development of hypergastrinemia in maintenance treatment for mild GERD using a half-dose PPI.