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.

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.

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.

Background: This study aimed to evaluate ChatGPT’s performance accuracy in responding to questions from the national dentalhygienist examination. Moreover, through an analysis of ChatGPT’s incorrect responses, this research intended to pinpoint the predominant types of errors. Methods: To evaluate ChatGPT-3.5’s performance according to the type of national examination questions, the researchers classified 200 questions of the 49th National Dental Hygienist Examination into recall, interpretation, and solving type questions. The researchers strategically modified the questions to counteract potential misunderstandings from implied meanings or technical terminology in Korea. To assess ChatGPT-3.5’s problem-solving capabilities in applying previously acquired knowledge, the questions were first converted to subjective type. If ChatGPT-3.5 generated an incorrect response, an original multiple-choice framework was provided again. Two hundred questions were input into ChatGPT-3.5 and the generated responses were analyzed.After using ChatGPT, the accuracy of each response was evaluated by researchers according to the types of questions, and the types of incorrect responses were categorized (logical, information, and statistical errors). Finally, hallucination was evaluated when ChatGPT provided misleading information by answering something that was not true as if it were true. Results: ChatGPT’s responses to the national examination were 45.5% accurate. Accuracy by question type was 60.3% for recall and 13.0% for problem-solving type questions. The accuracy rate for the subjective solving questions was 13.0%, while the accuracy for the objective questions increased to 43.5%. The most common types of incorrect responses were logical errors 65.1% of all. Of the total 102 incorrectly answered questions, 100 were categorized as hallucinations. Conclusion ChatGPT-3.5 was found to be limited in its ability to provide evidence-based correct responses to the Korean nationaldental hygiene examination. Therefore, dental hygienists in the education or clinical fields should be careful to use artificial intelligence-generated materials with a critical view.

Purpose: Neutrophils contribute to thrombosis. However, there is limited information on the temporal course of neutrophil recruitment in thrombosis, the contribution of neutrophils to thrombus growth, and the characteristics of stroke patients with neutrophil-rich thrombi. Materials and Methods: After inducing carotid artery thrombosis in Institute of Cancer Research mice using ferric chloride, aged thrombi were produced by ligating the distal portion of the carotid artery in mice for 0.5, 1, 2, 3, 6, or 24 h. For thrombus analysis in stroke patients, we used registry data and thrombi that were obtained during intra-arterial thrombectomy. Immunohistochemistry was performed to determine thrombus composition. Results: In the thrombi of 70 mice, Ly6G positive cell counts (neutrophils) and histone H3-positive cell counts increased in a time-dependent manner (both p<0.001). Ly6G-positive cell count was strongly correlated with histone H3-positive cell counts (r=0.910, p<0.001), but not with thrombus size (p=0.320). In 75 stroke patients, atrial fibrillation and cardioembolism were more frequent in the higher neutrophil group (32/37, 86.5%) than in the lower neutrophil group (19/38, 50%) (p=0.002). The median erythrocyte fraction was higher [52.0 (interquartile range 39.9−57.8)] in the higher neutrophil group than in the lower neutrophil group [40.3 (interquartile range 23.5−53.2)]. The fraction of neutrophils was positively correlated with that of erythrocytes (R=0.35, p=0.002). Conclusion Neutrophils were recruited and increased in arterial thrombosis in a time-dependent manner; however, they were not associated with the growth of formed thrombi. Neutrophil fractions in the thrombi of stroke patients appeared to be associated with atrial fibrillation and erythrocyte fraction.

Purpose: Neutrophils contribute to thrombosis. However, there is limited information on the temporal course of neutrophil recruitment in thrombosis, the contribution of neutrophils to thrombus growth, and the characteristics of stroke patients with neutrophil-rich thrombi. Materials and Methods: After inducing carotid artery thrombosis in Institute of Cancer Research mice using ferric chloride, aged thrombi were produced by ligating the distal portion of the carotid artery in mice for 0.5, 1, 2, 3, 6, or 24 h. For thrombus analysis in stroke patients, we used registry data and thrombi that were obtained during intra-arterial thrombectomy. Immunohistochemistry was performed to determine thrombus composition. Results: In the thrombi of 70 mice, Ly6G positive cell counts (neutrophils) and histone H3-positive cell counts increased in a time-dependent manner (both p<0.001). Ly6G-positive cell count was strongly correlated with histone H3-positive cell counts (r=0.910, p<0.001), but not with thrombus size (p=0.320). In 75 stroke patients, atrial fibrillation and cardioembolism were more frequent in the higher neutrophil group (32/37, 86.5%) than in the lower neutrophil group (19/38, 50%) (p=0.002). The median erythrocyte fraction was higher [52.0 (interquartile range 39.9−57.8)] in the higher neutrophil group than in the lower neutrophil group [40.3 (interquartile range 23.5−53.2)]. The fraction of neutrophils was positively correlated with that of erythrocytes (R=0.35, p=0.002). Conclusion Neutrophils were recruited and increased in arterial thrombosis in a time-dependent manner; however, they were not associated with the growth of formed thrombi. Neutrophil fractions in the thrombi of stroke patients appeared to be associated with atrial fibrillation and erythrocyte fraction.

Applying work restrictions for asymptomatic healthcare personnel (HCP) with potential exposure to coronavirus disease 2019 (COVID-19) is recommended to prevent transmission from potentially contagious HCP to patients and other HCP. However, it can lead to understaffing, which threatens the safety of both patients and HCP. We evaluated 203 COVID-19 exposure events at a single tertiary hospital from January 2020 to June 2021. A total of 2,365 HCP were potentially exposed, and work restrictions were imposed on 320 HCP, leading to the loss of 3,311 working days. However, only one of the work-restricted HCP was confirmed with COVID-19. During the study period, the work restriction measures might be taken excessively compared to their benefit, so establishing more effective standards for work restriction is required.

Objectives: . We evaluated changes in income levels in a hearing-impaired population. Methods: . The study subjects were selected from the Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2015 of Koreans ≥40 years old. In total, 5,857 hearing-impaired subjects were matched with 23,428 comparison participants. Differences between the initial income level and income levels at 1, 2, 3, 4, and 5 years post-enrollment were compared between the hearing-impaired and comparison groups. The interaction of time and hearing impairment/comparison was estimated. Results: . Both the hearing-impaired group and the comparison group showed increased income levels over time. In the hearing-impaired group, the income levels at 4 and 5 years post-enrollment were higher than the initial income level (each P<0.001). In the comparison group, the income levels of all the participants after 1–5 years were higher than the initial income level (each P<0.001). The interaction of time and hearing impairment was statistically significant (P=0.021). Conclusion . The increase in income over time was relatively lower in the hearing-impaired adult population; therefore, the income gap widened between this population and the normal-hearing population.

Objectives: . We evaluated changes in income levels in a hearing-impaired population. Methods: . The study subjects were selected from the Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2015 of Koreans ≥40 years old. In total, 5,857 hearing-impaired subjects were matched with 23,428 comparison participants. Differences between the initial income level and income levels at 1, 2, 3, 4, and 5 years post-enrollment were compared between the hearing-impaired and comparison groups. The interaction of time and hearing impairment/comparison was estimated. Results: . Both the hearing-impaired group and the comparison group showed increased income levels over time. In the hearing-impaired group, the income levels at 4 and 5 years post-enrollment were higher than the initial income level (each P<0.001). In the comparison group, the income levels of all the participants after 1–5 years were higher than the initial income level (each P<0.001). The interaction of time and hearing impairment was statistically significant (P=0.021). Conclusion . The increase in income over time was relatively lower in the hearing-impaired adult population; therefore, the income gap widened between this population and the normal-hearing population.

Applying work restrictions for asymptomatic healthcare personnel (HCP) with potential exposure to coronavirus disease 2019 (COVID-19) is recommended to prevent transmission from potentially contagious HCP to patients and other HCP. However, it can lead to understaffing, which threatens the safety of both patients and HCP. We evaluated 203 COVID-19 exposure events at a single tertiary hospital from January 2020 to June 2021. A total of 2,365 HCP were potentially exposed, and work restrictions were imposed on 320 HCP, leading to the loss of 3,311 working days. However, only one of the work-restricted HCP was confirmed with COVID-19. During the study period, the work restriction measures might be taken excessively compared to their benefit, so establishing more effective standards for work restriction is required.