As China accelerates its efforts in deep space exploration and long-duration space missions, including the operationalization of the Tiangong Space Station and the development of manned lunar missions, safeguarding astronauts’ physiological and cognitive functions under extreme space conditions becomes a pressing scientific imperative. Among the multifactorial stressors of spaceflight, microgravity emerges as a particularly potent disruptor of neurobehavioral homeostasis. Dopamine (DA) plays a central role in regulating behavior under space microgravity by influencing reward processing, motivation, executive function and sensorimotor integration. Changes in gravity disrupt dopaminergic signaling at multiple levels, leading to impairments in motor coordination, cognitive flexibility, and emotional stability. Microgravity exposure induces a cascade of neurobiological changes that challenge dopaminergic stability at multiple levels: from the transcriptional regulation of DA synthesis enzymes and the excitability of DA neurons, to receptor distribution dynamics and the efficiency of downstream signaling pathways. These changes involve downregulation of tyrosine hydroxylase in the substantia nigra, reduced phosphorylation of DA receptors, and alterations in vesicular monoamine transporter expression, all of which compromise synaptic DA availability. Experimental findings from space analog studies and simulated microgravity models suggest that gravitational unloading alters striatal and mesocorticolimbic DA circuitry, resulting in diminished motor coordination, impaired vestibular compensation, and decreased cognitive flexibility. These alterations not only compromise astronauts’ operational performance but also elevate the risk of mood disturbances and motivational deficits during prolonged missions. The review systematically synthesizes current findings across multiple domains: molecular neurobiology, behavioral neuroscience, and gravitational physiology. It highlights that maintaining DA homeostasis is pivotal in preserving neuroplasticity, particularly within brain regions critical to adaptation, such as the basal ganglia, prefrontal cortex, and cerebellum. The paper also discusses the dual-edged nature of DA plasticity: while adaptive remodeling of synapses and receptor sensitivity can serve as compensatory mechanisms under stress, chronic dopaminergic imbalance may lead to maladaptive outcomes, such as cognitive rigidity and motor dysregulation. Furthermore, we propose a conceptual framework that integrates homeostatic neuroregulation with the demands of space environmental adaptation. By drawing from interdisciplinary research, the review underscores the potential of multiple intervention strategies including pharmacological treatment, nutritional support, neural stimulation techniques, and most importantly, structured physical exercise. Recent rodent studies demonstrate that treadmill exercise upregulates DA transporter expression in the dorsal striatum, enhances tyrosine hydroxylase activity, and increases DA release during cognitive tasks, indicating both protective and restorative effects on dopaminergic networks. Thus, exercise is highlighted as a key approach because of its sustained effects on DA production, receptor function, and brain plasticity, making it a strong candidate for developing effective measures to support astronauts in maintaining cognitive and emotional stability during space missions. In conclusion, the paper not only underscores the centrality of DA homeostasis in space neuroscience but also reflects the authors’ broader academic viewpoint: understanding the neurochemical substrates of behavior under microgravity is fundamental to both space health and terrestrial neuroscience. By bridging basic neurobiology with applied space medicine, this work contributes to the emerging field of gravitational neurobiology and provides a foundation for future research into individualized performance optimization in extreme environments.

OBJECTIVE To compare the clinical efficacy and safety of camrelizumab combined with apatinib versus camrelizumab combined with chemotherapy as first-line treatment for advanced gastric cancer. METHODS A prospective randomized controlled trial was conducted， enrolling 99 patients with advanced gastric cancer admitted to the Chuzhou First People’s Hospital from March 2022 to December 2024. Patients were randomly assigned using a random number table： 48 received camrelizumab plus chemotherapy （control group）， and 51 received camrelizumab plus apatinib （observation group）. Clinical efficacy， serum tumor marker[carcinoembryonic antigen（CEA），carbohydrate antigen（CA）724，CA199，CA242]levels， immune function indicators（CD3+，CD4+，CD8+，CD4+/CD8+） levels before and after treatment， and adverse drug reaction （ADR） during treatment were compared between the 2 groups. RESULTS A total of 2 patients in the observation group and 3 in the control group were lost to follow-up. The disease control rate and objective response rate in the observation group were 95.92% and 85.71%， respectively， both significantly higher than 80.00% and 55.56% in the control group （P＜0.05）. The median progression-free survival was 9.61 months in the observation group， significantly longer than 6.72 months in the control group （P＝0.011）. Before treatment， there was no statistically significant difference in the levels of serum tumor markers and immune function indicators between the 2 groups （P＞0.05）. After treatment， the levels of CEA， CA724， CA199 and CA242 in 2 groups were significantly lower than before treatment， while the levels of CD3⁺， CD4⁺ and CD4 ⁺/CD8 ⁺ were significantly higher than before treatment， with greater improvements in the observation group （all P＜0.05）. The overall incidences of ADR and severe ADR showed no statistically significant difference between the 2 groups （P＞0.05）. CONCLUSIONS Camrelizumab combined with apatinib as first-line therapy for advanced gastric cancer may offer advantages over camrelizumab plus chemotherapy in terms of clinical efficacy and immune function improvement of patients， with an acceptable safety profile.

Background/Aims: We investigated the clinical practice patterns of Korean endoscopists for the endoscopic resection of colorectal polyps. Methods: From September to November 2021, an online survey was conducted regarding the preferred resection methods for colorectal polyps, and responses were compared with the international guidelines. Results: Among 246 respondents, those with <4 years, 4–9 years, and ≥10 years of experiencein colonoscopy practices accounted for 25.6%, 34.1%, and 40.2% of endoscopists, respectively. The most preferred resection methods for non-pedunculated lesions were cold forceps polypectomy for ≤3 mm lesions (81.7%), cold snare polypectomy for 4–5 mm (61.0%) and 6–9 mm (43.5%) lesions, hot endoscopic mucosal resection (EMR) for 10–19 mm lesions (72.0%), precut EMR for 20–25 mm lesions (22.0%), and endoscopic submucosal dissection (ESD) for ≥26 mm lesions (29.3%). Hot EMR was favored for pedunculated lesions with a head size <20 mm and stalk size <10 mm (75.6%) and for those with a head size ≥20 mm or stalk size ≥10 mm (58.5%). For suspected superficial and deep submucosal lesions measuring 10–19 mm and ≥20 mm, ESD (26.0% and 38.6%) and surgery (36.6% and 46.3%) were preferred, respectively. The adherence rate to the guidelines ranged from 11.2% to 96.9%, depending on the size, shape, and histology of the lesions. Conclusions Adherence to the guidelines for endoscopic resection techniques varied depend-ing on the characteristics of colorectal polyps. Thus, an individualized approach is required to increase adherence to the guidelines.

Background/Aims: Infliximab treatment failure in patients with inflammatory bowel disease may result from sub-optimal infliximab trough level. An understanding of pharmacokinetics (PKs) is important to maintain an optimal trough level. PK studies of the switch to subcutaneous (SC) infliximab from intravenous (IV) infliximab using real-world data are lacking. We aimed to develop a population PK model of IV and SC infliximab to predict individual infliximab exposure during maintenance therapy. Methods: We used data from prospectively collected data on IV and SC infliximab concentrations in patients with inflammatory bowel disease receiving maintenance treatment from February 2020 to December 2022 at Samsung Medical Center. Population PK analysis was conducted by using a two-compartment model with first-order absorption and first-order elimination. Goodness-of-fit plots and visual predictive check were used to evaluate the PK model. Results: A total of 2,132 samples from 181 patients (149 Crohn’s disease and 32 ulcerative colitis) were analyzed. We developed an infliximab population PK model using body mass index, albumin, C-reactive protein level, and the anti-drug antibody level and validated its predictive performance. Conclusions It may be possible to predict the infliximab trough level of both IV and SC infliximab in patients with inflammatory bowel disease during maintenance treatment by using our model in real-world practice.

Purpose: Since 1995, the Korean Gastric Cancer Association (KGCA) has been periodically conducting nationwide surveys on patients with surgically treated gastric cancer. This study details the results of the survey conducted in 2023. Materials and Methods: The survey was conducted from March to December 2024 using a standardized case report form. Data were collected on 86 items, including patient demographics, tumor characteristics, surgical procedures, and surgical outcomes. The results of the 2023 survey were compared with those of previous surveys. Results: Data from 12,751 cases were collected from 66 institutions. The mean patient age was 64.6 years, and the proportion of patients aged ≥71 years increased from 9.1% in 1995 to 31.7% in 2023. The proportion of upper-third tumors slightly decreased to 16.8% compared to 20.9% in 2019. Early gastric cancer accounted for 63.1% of cases in 2023.Regarding operative procedures, a totally laparoscopic approach was most frequently applied (63.2%) in 2023, while robotic gastrectomy steadily increased to 9.5% from 2.1% in 2014.The most common anastomotic method was the Billroth II procedure (48.8%) after distal gastrectomy and double-tract reconstruction (51.9%) after proximal gastrectomy in 2023.However, the proportion of esophago-gastrostomy with anti-reflux procedures increased to 30.9%. The rates of post-operative mortality and overall complications were 1.0% and 15.3%, respectively. Conclusions The results of the 2023 nationwide survey demonstrate the current status of gastric cancer treatment in Korea. This information will provide a basis for future gastric cancer research.

Purpose: : This study aimed to explore the essence and meaning of light sedation for patients in the intensive care unit (ICU). Methods: : Individual in-depth interviews were conducted with 10 patients receiving light sedation therapy in the cardiac ICU of a university hospital in South Korea. The content of the interviews was analyzed using Elo and Kyngäs’s inductive content analysis method. Data collection and analysis were performed iteratively to enable a continuous comparative analysis. Results: : The main category derived from the analysis was the “coexistence of partial consciousness and discomfort.” Three general categories were identified: (1) the state of being neither asleep nor awake, (2) persistent discomfort, and (3) ambivalence toward consciousness. The subcategories included a fragmented memory, disorientation, surreal experiences, brain fog, half-heard noises, physical discomfort, mental distress, preference for sleep, and preference for being awake. Conclusion : Patients in the ICU under light sedation experienced an incomplete state of consciousness while experiencing various types of discomfort. Nurses should understand the patients’ subjective experiences with light sedation to provide patient-centered care. Based on these findings, further research is required to develop and apply nursing interventions for patients under light sedation.

Purpose: : This study aimed to explore the essence and meaning of light sedation for patients in the intensive care unit (ICU). Methods: : Individual in-depth interviews were conducted with 10 patients receiving light sedation therapy in the cardiac ICU of a university hospital in South Korea. The content of the interviews was analyzed using Elo and Kyngäs’s inductive content analysis method. Data collection and analysis were performed iteratively to enable a continuous comparative analysis. Results: : The main category derived from the analysis was the “coexistence of partial consciousness and discomfort.” Three general categories were identified: (1) the state of being neither asleep nor awake, (2) persistent discomfort, and (3) ambivalence toward consciousness. The subcategories included a fragmented memory, disorientation, surreal experiences, brain fog, half-heard noises, physical discomfort, mental distress, preference for sleep, and preference for being awake. Conclusion : Patients in the ICU under light sedation experienced an incomplete state of consciousness while experiencing various types of discomfort. Nurses should understand the patients’ subjective experiences with light sedation to provide patient-centered care. Based on these findings, further research is required to develop and apply nursing interventions for patients under light sedation.

Purpose: : This study aimed to explore the essence and meaning of light sedation for patients in the intensive care unit (ICU). Methods: : Individual in-depth interviews were conducted with 10 patients receiving light sedation therapy in the cardiac ICU of a university hospital in South Korea. The content of the interviews was analyzed using Elo and Kyngäs’s inductive content analysis method. Data collection and analysis were performed iteratively to enable a continuous comparative analysis. Results: : The main category derived from the analysis was the “coexistence of partial consciousness and discomfort.” Three general categories were identified: (1) the state of being neither asleep nor awake, (2) persistent discomfort, and (3) ambivalence toward consciousness. The subcategories included a fragmented memory, disorientation, surreal experiences, brain fog, half-heard noises, physical discomfort, mental distress, preference for sleep, and preference for being awake. Conclusion : Patients in the ICU under light sedation experienced an incomplete state of consciousness while experiencing various types of discomfort. Nurses should understand the patients’ subjective experiences with light sedation to provide patient-centered care. Based on these findings, further research is required to develop and apply nursing interventions for patients under light sedation.