Sleep–wake regulation is controlled by circadian and homeostatic processes, with adenosine acting as a key molecular mediator of homeostatic sleep pressure. Extracellular adenosine accumulates during wakefulness as a result of neuronal energy metabolism, particularly in the basal forebrain, and declines during recovery sleep, thereby reflecting the physiological need for sleep.The sleep-promoting effects of adenosine are mediated primarily by two G protein–coupled receptor subtypes, the adenosine A1 receptor and the adenosine A2A receptor. The adenosine A1 receptor, coupled to inhibitory Gi/o proteins and widely expressed in the cortex, hippocampus, thalamus, and basal forebrain, suppresses wake-promoting neuronal activity and facilitates slow-wave activity during non-rapid eye movement sleep. In contrast, the adenosine A2A receptor, coupled to stimulatory Golf proteins and enriched in the striatum and nucleus accumbens, promotes sleep by activating neurons in the preoptic hypothalamus and engaging the indirect basal ganglia pathway. Despite these well-established roles, the contributions of dysregulation of the adenosine A1 receptor and the adenosine A2A receptor to specific sleep disorders remain incompletely understood. This review examines how signaling of the adenosine A1 receptor and the adenosine A2A receptor is altered in insomnia, obstructive sleep apnea, narcolepsy, and restless legs syndrome, and evaluates the therapeutic potential of receptor-selective strategies for adenosine receptor–targeted treatment.

Background/Aims: Cardiovascular disease remains a major cause of mortality in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This study evaluated the association between subclinical carotid atherosclerosis (SCA) and MASLD or MASLD and increased alcohol intake (MetALD) in asymptomatic individuals. Methods: This cross-sectional study included 56,889 adults undergoing health check-ups in South Korea. Hepatic steatosis was diagnosed by ultrasound, and SCA was defined by carotid plaques or increased intima-media thickness. Liver fibrosis was evaluated using the fibrosis-4 index and elastography. Results: SCA was identified in 13.5%. MASLD and MetALD were significantly associated with SCA in models adjusted for demographic and lifestyle factors (adjusted odds ratio [aOR], 1.26;95% confidence interval [CI], 1.19 to 1.33; aOR, 1.43; 95% CI, 1.30 to 1.58; respectively, p<0.001for both). However, these associations attenuated and lost statistical significance when metabolic risk factors were further adjusted. The risk of SCA increased with greater hepatic steatosis and liver fibrosis severity. In patients with MASLD, aORs were 1.70 (hepatic steatosis index >36),1.23 (fibrosis-4 index ≥1.3), and 1.78 (liver stiffness measurement ≥5.6 kPa), compared to indi-viduals without MASLD. Similar trends were observed in the MetALD group. Additionally, hyper-tension and clustering of ≥3 cardiometabolic risk factors were significantly associated with SCA inthe MASLD group, supporting the role of metabolic burden in SCA development. Conclusions MASLD and MetALD were associated with increased SCA risk, particularly in individuals with hepatic steatosis and fibrosis. These findings suggest that metabolic burden and liver disease severity jointly contribute to subclinical atherosclerosis risk.

Background: Healthcare-associated infections impose a significant burden on antibiotic usage, healthcare expenditures, and morbidity. Therefore, it is crucial to revise policies to minimize such losses. This nationwide survey aimed to evaluate infection prevention and control (IPC) components in healthcare facilities and encourage improvements in acute care hospitals with inadequate infection prevention settings. This study aims to enhance the infection control capabilities of healthcare facilities. Methods: From December 27, 2021, to May 13, 2022, we conducted a survey of 1,767 acute care hospitals in the Republic of Korea. A survey was conducted to evaluate the infection control components in 1,767 acute care hospitals. Infection control officers provided direct responses to a systematically developed questionnaire. Subsequently, 10% of the respondents were randomly selected for the site investigation. Results: Overall, 1,197 (67.7%) hospitals responded to the online survey. On-site investigations were conducted at 125 hospitals. Hospitals with ≥ 150 beds are advised to have an IPC team under Article 3 of the Medical Service Act; however, only 87.0% (598/687) of hospitals with ≥ 100 beds had one. Conversely, 22.7% (116/510) of hospitals with < 100 beds had an IPC team. Regulations for hand hygiene, waste management, healthcare worker protection and safety, environmental cleaning, standard precautions, and prevention of the transmission of multidrug-resistant pathogens were present in 84.2%, 80.1%, 77.4%, 76.2%, 75.8%, and 63.5% of the hospitals, respectively. Hospitals with < 100 beds had low availability of all categories of standard operating procedures. Conclusion This study is the first national survey of acute care hospitals in the Republic of Korea. The data presented in the current study will improve the understanding of IPC status and will help establish a survey system. Our survey provides a basis for improving policies related to IPC in healthcare facilities.

Purpose: Claudin 18.2 (CLDN18.2) has emerged as a promising therapeutic target for CLDN18.2-expressing gastric cancer (GC). We sought to examine the heterogeneity of CLDN18.2 expression between primary GC (PGC) and metastatic GC (MGC) using various scoring methods. Materials and Methods: We retrospectively analyzed data from 102 patients with pathologically confirmed paired primary and metastatic gastric or gastroesophageal junction adenocarcinomas. CLDN18.2 expression was evaluated through immunohistochemistry on formalin-fixed paraffin-embedded tissue samples. We assessed CLDN18.2 positivity using multiple scoring approaches, including the immunoreactivity score, H-score, and the percentage of tumor cells showing moderate-to-strong staining intensity. We analyzed the concordance rates between PGC and MGC and the association of CLDN18.2 positivity with clinicopathological features. Results: CLDN18.2 positivity varied from 25% to 65% depending on the scoring method, with PGC consistently showing higher expression levels than MGC. Intratumoral heterogeneity was noted in 25.5% of PGCs and 19.6% of MGCs. Intertumoral heterogeneity, manifesting as discordance in CLDN18.2 positivity between PGC and MGC, was observed in about 20% of cases, with moderate agreement across scoring methods (κ=0.47 to 0.60).In PGC, higher CLDN18.2 positivity correlated with synchronous metastasis, presence of peritoneal metastasis, poorly differentiated grade, and biopsy specimens. In MGC, positivity was associated with synchronous metastasis, presence of peritoneal metastasis, and metastatic peritoneal tissues. Conclusions CLDN18.2 expression demonstrates significant heterogeneity between PGC and MGC, with a 20% discordance rate. Comprehensive tissue sampling and reassessment of CLDN18.2 status are crucial, especially before initiating CLDN18.2-targeted therapies.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Conversion therapy is a treatment strategy that shifts from palliative systemic therapy to curative surgical treatment for primary and/or metastatic stage IV gastric cancer (GC).To address its clinical statements, the Korean Gastric Cancer Association aims to present a consensus on conversion therapy among experts attending KINGCA WEEK 2024. The KINGCA Scientific Committee and Development Working Group for Korean Practice Guidelines prepared preformulated topics and 9 clinical statements for conversion therapy.The Delphi method was applied to a panel of 17 experts for consensus and opinions. The final comments were announced after the statement presentation and discussed during the consensus meeting session of KINGCA WEEK 2024. Most experts agreed that conversion herapy provides a survival benefit for selected patients who respond to systemic therapy and undergo R0 resection (88.3%). Patients with limited metastases were considered good candidates (94.2%). The optimal timing was based on the response to systemic therapy (70.6%). The regimen was recommended to be individualized (100%) and the duration to be at least 6 months (88.3%). A minimally invasive approach (82.3%) and D2 lymph node dissection (82.4%) were considered for surgery. However, resection for metastases with a complete clinical response after systemic therapy was not advocated (41.2%). All experts agreed on the need for large-scale randomized-controlled trials for further evidence (100%).Recent advancements in treatment may facilitate radical surgery for patients with stage IV GC. Further evidence is warranted to establish the safety and efficacy of conversion therapy.

Purpose: The career ladder system is a pivotal strategy for securing excellent nurses. The aim of this study is to understand hospital nurses’ experiences of participating in the career ladder system and to explore the essence of this system. Methods: In February 22 to March 3, 2022, nurses employed at a general hospital in South Korea were selected for this study using snowball and purposive sampling. Data were collected from interviews with three focus groups, the compositions of which are as follows: group 1, 6 participants; group 2, 5 participants; and group 3, 6 participants. All interviews were recorded, transcribed verbatim, and subsequently analyzed using qualitative research methods. Results: The following six categories were derived under the overall theme of “the arduous journey to discovering a nurse’s true name”: (1) rites of passage to becoming the ideal nurse; (2) unexpected challenges in the promotion preparation process; (3) biased criteria for evaluating nursing competencies; (4) unclear changes in roles and perceptions after promotion; (5) self-discovered pride and fulfillment as a nurse; and (6) the unspoken struggles of evaluators. Conclusion The findings suggest that the career ladder system fosters nurses’ professional growth and self-actualization. However, for effective implementation, nurses’ deep understanding and systematic management of the career ladder system are essential. This study offers valuable insights and benchmarks for healthcare institutions aiming to adopt the system.

Background: Healthcare-associated infections impose a significant burden on antibiotic usage, healthcare expenditures, and morbidity. Therefore, it is crucial to revise policies to minimize such losses. This nationwide survey aimed to evaluate infection prevention and control (IPC) components in healthcare facilities and encourage improvements in acute care hospitals with inadequate infection prevention settings. This study aims to enhance the infection control capabilities of healthcare facilities. Methods: From December 27, 2021, to May 13, 2022, we conducted a survey of 1,767 acute care hospitals in the Republic of Korea. A survey was conducted to evaluate the infection control components in 1,767 acute care hospitals. Infection control officers provided direct responses to a systematically developed questionnaire. Subsequently, 10% of the respondents were randomly selected for the site investigation. Results: Overall, 1,197 (67.7%) hospitals responded to the online survey. On-site investigations were conducted at 125 hospitals. Hospitals with ≥ 150 beds are advised to have an IPC team under Article 3 of the Medical Service Act; however, only 87.0% (598/687) of hospitals with ≥ 100 beds had one. Conversely, 22.7% (116/510) of hospitals with < 100 beds had an IPC team. Regulations for hand hygiene, waste management, healthcare worker protection and safety, environmental cleaning, standard precautions, and prevention of the transmission of multidrug-resistant pathogens were present in 84.2%, 80.1%, 77.4%, 76.2%, 75.8%, and 63.5% of the hospitals, respectively. Hospitals with < 100 beds had low availability of all categories of standard operating procedures. Conclusion This study is the first national survey of acute care hospitals in the Republic of Korea. The data presented in the current study will improve the understanding of IPC status and will help establish a survey system. Our survey provides a basis for improving policies related to IPC in healthcare facilities.

This study examined the KHEI (Korean Healthy Eating Index) in elderly men and women according to their income level using the National Health and Nutrition Survey (2020∼2021) data. The income level was classified into lower, lower middle, upper middle, and upper groups according to the household income quartiles. The significant differences between the KHEI score and three subcategories (adequacy, moderation, energy balance) scores according to the income level showed the same pattern in the elderly total, men and women. Regarding the individual item, the score for the intake of meat, fish, eggs, legumes, total fruit, fresh fruit, total vegetables, and vegetables excluding kimchi and pickled vegetables were significantly lower in the lower income group in total elderly, men and women than in the other groups (P＜0.001). Among the items that showed differences between elderly men and women, the ‘regular breakfast’ score was lowest in the upper-income group of elderly men and the ‘mixed grains intake’ score was lowest in the lower-income group of elderly men. These results can be used to help develop nutrition policies and national nutritional interventions for the elderly population according to the income level.

Ketone bodies produced by sodium-glucose cotransporter 2 (SGLT2) inhibitors can be advantageous, providing an efficient and stable energy source for the brain and muscles. However, in patients with diabetes, ketogenesis induced by SGLT2 inhibitors may be harmful, potentially resulting in severe diabetic ketoacidosis (DKA). During fasting, ketone body production serves as an alternative and efficient energy source for the brain by utilizing stored fat, promoting mental clarity, and reducing dependence on glucose. The concurrent use of SGLT2 inhibitors during perioperative fasting may further elevate the risk of euglycemic DKA. We describe a case of DKA that occurred during perioperative fasting in a patient receiving empagliflozin, an SGLT2 inhibitor. This case underscores the importance of recognizing the potential risk of DKA in patients with diabetes using SGLT2 inhibitors during perioperative fasting.