In the auditory system, the spontaneous activity of cochlear inner hair cells (IHCs) is initiated by the release of ATP from inner supporting cells (ISCs). This ATP release sets off a cascade, activating purinergic autoreceptors, opening of Ca 2+ -activated Cl- channel TMEM16A, Cl- efflux and osmotic cell shrinkage. Then, the shrunken ISCs efficiently regain their original volume, suggesting the existence of mechanisms for refilling Cl- and K + , priming them for subsequent activity. This study explores the potential involvement of NKCCs (Na+ -K+ -Cl- cotransporters) and KCCs (K+ -Cl- cotransporters) in ISC spontaneous activity, considering their capability to transport both Cl- and K+ ions across the cell membrane. Employing a combination of immunohistochemistry, pharmacological interventions, and shRNA experiment, we unveiled the pivotal role of NKCC1 in cochlear spontaneous activity. Immunohistochemistry revealed robust NKCC1 expression in ISCs, persisting until the 2nd postnatal week. Intriguingly, we observed a developmental shift in NKCC1 expression from ISCs to synaptophysin-positive efferent terminals at postnatal day 18, hinting at its potential involvement in modulating synaptic transmission during the post-hearing period. Experiments using bumetanide, a well-known NKCC inhibitor, supported the functional significance of NKCC1 in ISC spontaneous activity. Bumetanide significantly reduced the frequency of spontaneous extracellular potentials (sEP) and spontaneous optical changes (sOCs) in ISCs. NKCC1-shRNA experiments conducted in cultured cochlear tissues further supported these findings, demonstrating a substantial decrease in event frequency and area. Taken together, we revealed the role of NKCC1 in shaping the ISC spontaneous activity that govern auditory pathway development.

Purpose: The duties of paramedics and emergency medical technicians (P&EMTs) are continuously changing due to developments in medical systems. This study presents evaluation goals for P&EMTs by analyzing their work, especially the tasks that new P&EMTs (with less than 3 years’ experience) find difficult, to foster the training of P&EMTs who could adapt to emergency situations after graduation. Methods: A questionnaire was created based on prior job analyses of P&EMTs. The survey questions were reviewed through focus group interviews, from which 253 task elements were derived. A survey was conducted from July 10, 2023 to October 13, 2023 on the frequency, importance, and difficulty of the 6 occupations in which P&EMTs were employed. Results: The P&EMTs’ most common tasks involved obtaining patients’ medical histories and measuring vital signs, whereas the most important task was cardiopulmonary resuscitation (CPR). The task elements that the P&EMTs found most difficult were newborn delivery and infant CPR. New paramedics reported that treating patients with fractures, poisoning, and childhood fever was difficult, while new EMTs reported that they had difficulty keeping diaries, managing ambulances, and controlling infection. Conclusion Communication was the most important item for P&EMTs, whereas CPR was the most important skill. It is important for P&EMTs to have knowledge of all tasks; however, they also need to master frequently performed tasks and those that pose difficulties in the field. By deriving goals for evaluating P&EMTs, changes could be made to their education, thereby making it possible to train more capable P&EMTs.

Objective: Automated breast ultrasound (ABUS) is a relevant imaging technique for early breast cancer diagnosis and is increasingly being used as a supplementary tool for mammography. This study compared the performance of ABUS and handheld ultrasound (HHUS) in detecting and characterizing the axillary lymph nodes (LNs) in patients with breast cancer. Materials and Methods: We retrospectively reviewed the medical records of women with recently diagnosed early breast cancer (≤ T2) who underwent both ABUS and HHUS examinations for axilla (September 2017–May 2018). ABUS and HHUS findings were compared using pathological outcomes as reference standards. Diagnostic performance in predicting any axillary LN metastasis and heavy nodal-burden metastases (i.e., ≥ 3 LNs) was evaluated. The ABUS-HHUS agreement for visibility and US findings was calculated. Results: The study included 377 women (53.1 ± 11.1 years). Among 385 breast cancers in 377 patients, 101 had axillary LN metastases and 30 had heavy nodal burden metastases. ABUS identified benign-looking or suspicious axillary LNs (average, 1.4 ± 0.8) in 246 axillae (63.9%, 246/385). According to the per-breast analysis, the sensitivity, specificity, positive and negative predictive values, and accuracy of ABUS in predicting axillary LN metastases were 43.6% (44/101), 95.1% (270/284), 75.9% (44/58), 82.6% (270/327), and 81.6% (314/385), respectively. The corresponding results for HHUS were 41.6% (42/101), 95.1% (270/284), 75.0% (42/56), 82.1% (270/329), and 81.0% (312/385), respectively, which were not significantly different from those of ABUS (P ≥ 0.53). The performance results for heavy nodal-burden metastases were 70.0% (21/30), 89.6% (318/355), 36.2% (21/58), 97.3% (318/327), and 88.1% (339/385), respectively, for ABUS and 66.7% (20/30), 89.9% (319/355), 35.7% (20/56), 97.0% (319/329), and 88.1% (339/385), respectively, for HHUS, also not showing significant difference (P ≥ 0.57). The ABUS–HHUS agreement was 95.9% (236/246; Cohen’s kappa = 0.883). Conclusion Although ABUS showed limited sensitivity in diagnosing axillary LN metastasis in early breast cancer, it was still useful as the performance was comparable to that of HHUS.

Purpose: Several predictive models have been developed to predict the pathological complete response (pCR) after neoadjuvant chemotherapy (NAC); however, few are broadly applicable owing to radiologic complexity and institution-specific clinical variables, and none have been externally validated. This study aimed to develop and externally validate a machine learning model that predicts pCR after NAC in patients with breast cancer using routinely collected clinical and demographic variables. Methods: The electronic medical records of patients with advanced breast cancer who underwent NAC before surgical resection between January 2017 and December 2020 were reviewed. Patient data from Seoul National University Bundang Hospital were divided into training and internal validation cohorts. Five machine learning techniques, including gradient boosting machine (GBM), support vector machine, random forest, decision tree, and neural network, were used to build predictive models, and the area under the receiver operating characteristic curve (AUC) was compared to select the best model. Finally, the model was validated using an independent cohort from Seoul National University Hospital. Results: A total of 1,003 patients were included in the study: 287, 71, and 645 in the training, internal validation, and external validation cohorts, respectively. Overall, 36.3% of the patients achieved pCR. Among the five machine learning models, the GBM showed the highest AUC for pCR prediction (AUC, 0.903; 95% confidence interval [CI], 0.833–0.972).External validation confirmed an AUC of 0.833 (95% CI, 0.800–0.865). Conclusion Commonly available clinical and demographic variables were used to develop a machine learning model for predicting pCR following NAC. External validation of the model demonstrated good discrimination power, indicating that routinely collected variables were sufficient to build a good prediction model.

Objectives: This study aimed to assess the scale and transmission patterns of coronavirus disease 2019 (COVID-19) in a religious village community in South Korea, to determine the risk factors of transmission, and to evaluate vaccine effectiveness. Methods: An epidemiological survey was conducted, and data were collected and analyzed from 602 villagers in the religious village community. Multivariate logistic regression analysis was used to identify the risk factors for COVID-19 transmission and to evaluate vaccine effectiveness. Results: The outbreak attack rate was 72.1% (434/602). The attack rate was high among women in their 60s, the unemployed, residents living near religious facility (<500 m), and the unvaccinated. Age, the distance between religious facility and residences, and the absence of vaccination were identified as risk factors for infection. Vaccine effectiveness was 49.0%, and the highest effectiveness was seen in the age group of 59 years or younger (65.8%). Conclusion This village community was isolated, with little communication with the outside world. However, the frequency of close contact between residents was relatively high, contributing to the spread of COVID-19 in the village even with relatively short exposure. Vaccination rates in the village community were also lower than those in the general public. Public health authorities should consider the potential impact of cultural factors, including religion, that could lead to the exponential spread of COVID-19 in closed village communities.

Purpose: Breast cancer is mainly diagnosed using core needle biopsy (CNB), although other biopsy methods, including vacuum-assisted biopsy (VAB), may also be used. We compared differences in clinical characteristics and prognoses of patients with breast cancer according to biopsy methods used for diagnosis. Methods: A total of 98,457 patients who underwent various biopsy methods (CNB, fine-needle aspiration [FNA], VAB, and excisional biopsy) for diagnosing breast cancer were recruited. Using CNB as a reference, related clinicopathological factors and prognostic differences between biopsy methods were analyzed retrospectively using large-scale data from the Korean Breast Cancer Society Registration System. The associations between biopsy methods and clinicopathological factors were compared using multinomial logistic regression analysis, and the prognoses of patients undergoing the different biopsy methods, as breast cancer-specific survival (BCSS) and overall survival (OS), were compared using the Kaplan-Meier method and Cox proportional hazard model. Results: Univariate and multivariate analyses showed that unlike FNA, both VAB and excisional biopsy were significantly associated with tumor size, palpability, tumor stage, and histologic grade as relatively good prognostic factors compared to CNB. In particular, VAB showed lower odds ratios for these factors than excisional biopsy. In the univariate analysis, the prognosis of patients undergoing VAB was better than that of those undergoing CNB with respect to BCSS (hazard ratio [HR], 0.188, p < 0.001) and OS (HR, 0.359; p < 0.001). However, in the multivariate analysis, there were no significant prognostic differences from CNB in both BCSS and OS; differences were only evident for FNA. Conclusion In this study, we showed that the characteristics of breast cancer differed according to various biopsy methods. Although VAB is not a standard method for breast cancer diagnosis, it showed no prognostic differences to CNB.

Purpose: The purpose of this study was to analyze the frequency and relevance of frequent keywords using text mining analysis for symptom-related telephone counseling of patients undergoing chemotherapy, and to understand the current status and characteristics of the nursing intervention. Methods: 442 cases of telephone counseling of patients undergoing chemotherapy were collected. The symptoms were classified and separated according to the contents of the consultation between the nurse and the counseling participants. Using the python library, frequency words were extracted, and the generation of word co-occurrence matrices was analyzed through social network analysis. Results: For the four cancers to be analyzed (breast, colorectum, stomach, lung), the common frequent words of nurse and counseling participants were ‘medical staff (uilyojin)’, ‘medical treatment (jinlyo)’, ‘treatment (chilyo)’, ‘other hospital (tabyeongwon)’, ‘prescription (cheobang)’. In the analysis of social networks, words with highly betweenness centrality, which appear in common, almost matched those of frequent words. Conclusion In this study, it was possible to extract the most frequent words by cancer type from the contents of telephone counseling with cancer patients and to understand the current status and context of the actual telephone counseling focusing on each keyword.

Background: The relationship between changes in anxiety levels and personal protective equipment (PPE) use is yet to be evaluated. The present study assessed this relationship among healthcare workers (HCWs) involved in the care of patients with coronavirus disease 2019 (COVID-19). Methods: An online survey was conducted in a municipal hospital with 195 nationally designated negative pressure isolation units in Korea. Anxiety level was measured using the self-rating anxiety scale (SAS), and changes in anxiety levels were assessed based on the time when COVID-19 vaccine was introduced in March 2021 in Korea. Monthly PPE usage between June 2020 and May 2021 was investigated. Results: The mean SAS score (33.25 ± 5.97) was within normal range and was lower than those reported in previous studies conducted before COVID-19 vaccination became available.Among the 93 HCWs who participated, 64 (68.8%) answered that their fear of contracting COVID-19 decreased after vaccination. The number of coveralls used per patient decreased from 33.6 to 0. However, a demand for more PPE than necessary was observed in situations where HCWs were exposed to body fluids and secretions (n = 38, 40.9%). Excessive demand for PPE was not related to age, working experience, or SAS score. Conclusion Anxiety in HCWs exposed to COVID-19 was lower than it was during the early period of the pandemic, and the period before vaccination was introduced. The number of coveralls used per patient also decreased although an excessive demand for PPE was observed.

Purpose: Estrogen receptor (ER) expression in breast cancer plays an essential role in carcinogenesis and disease progression. Recently, tumors with low level (1%-10%) of ER expression have been separately defined as ER low positive (ERlow). It is suggested that ERlow tumors might be morphologically and behaviorally different from tumors with high ER expression (ERhigh). Materials and Methods: Retrospective analysis of a prospective cohort database was performed. Patients who underwent curative surgery for early breast cancer and had available medical records were included for analysis. Difference in clinicopathological characteristics, endocrine responsiveness and five-year recurrence-free survival was evaluated between different ER subgroups (ERhigh, ERlow, and ER-negative [ER–]). Results: A total of 2,162 breast cancer patients were included in the analysis, Tis and T1 stage. Among them, 1,654 (76.5%) were ERhigh, 54 (2.5%) were ERlow, and 454 (21.0%) were ER- patients. ERlow cases were associated with smaller size, higher histologic grade, positive human epidermal growth factor receptor 2, negative progesterone receptor, and higher Ki-67 expression. Recurrence rate was highest in ER– tumors and was inversely proportional to ER expression. Recurrence-free survival was not affected by hormonal therapy in the ERlow group (p=0.418). Conclusion ERlow breast cancer showed distinct clinicopathological features. ERlow tumors seemed to have higher recurrence rates compared to ERhigh tumors, and they showed no significant benefit from hormonal therapy. Future large scale prospective studies are necessary to validate the treatment options for ERlow breast cancer.

Cochlear afferent nerve fibers (ANF) are the first neurons in the ascending auditory pathway. We investigated the low-voltage activating K + channels expressed in ANF dendrites using isolated rat cochlear segments. Whole cell patch clamp recordings were made from the dendritic terminals of ANFs. Outward currents activating at membrane potentials as low as -64 mV were observed in all dendrites studied. These currents were inhibited by 4-aminopyridine (4-AP), a blocker known to preferentially inhibit low-voltage activating K + currents (I KL ) in CNS auditory neurons and spiral ganglion neurons. When the dendritic I KL was blocked by 4-AP, the EPSP decay time was significantly prolonged, suggesting that dendritic I KL speeds up the decay of EPSPs and likely modulates action potentials of ANFs. To reveal molecular subtype of dendritic I KL , α-dendrotoxin (α-DTX), a selective inhibitor for K v 1.1, Kv 1.2, and K v 1.6 containing channels, was tested. α-DTX inhibited 23±9% of dendritic I KL . To identify the α-DTXsensitive and α-DTX-insensitive components of I KL , immunofluorescence labeling was performed. Strong K v 1.1- and K v 1.2-immunoreactivity was found at unmyelinated dendritic segments, nodes of Ranvier, and cell bodies of most ANFs. A small fraction of ANF dendrites showed K v 7.2-immunoreactivity. These data suggest that dendritic I KL is conducted through K v 1.1and K v 1.2 channels, with a minor contribution from K v 7.2 and other as yet unidentified channels.