Objective: To establish local diagnostic reference levels (DRLs) for pediatric neck CT based on age, weight, and water-equivalent diameter (WED) across multiple university hospitals in South Korea. Materials and Methods: This retrospective study analyzed pediatric neck CT examinations from nine university hospitals, involving patients aged 0–18 years. Data were categorized by age, weight, and WED, and radiation dose metrics, including volume CT dose index (CTDIvol) and dose length product, were recorded. Data retrieval and analysis were conducted using a commercially available dose-management system (Radimetrics, Bayer Healthcare). Local DRLs were established following the International Commission on Radiological Protection guidelines, using the 75th percentile as the reference value. Results: A total of 1159 CT examinations were analyzed, including 169 scans from Institution 1, 132 from Institution 2, 126 from Institution 3, 129 from Institution 4, 128 from Institution 5, 105 from Institution 6, 162 from Institution 7, 127 from Institution 8, and 81 from Institution 9. Radiation dose metrics increased with age, weight, and WED, showing significant variability both within and across institutions. For patients weighing less than 10 kg, the DRL for CTDIvol was 5.2 mGy. In the 10–19 kg group, the DRL was 5.8 mGy; in the 20–39 kg group, 7.6 mGy; in the 40–59 kg group, 11.0 mGy; and for patients weighing 60 kg or more, 16.2 mGy. DRLs for CTDIvol by age groups were as follows: 5.3 mGy for infants under 1 year, 5.7 mGy for children aged 1–4 years, 7.6 mGy for ages 5–9 years, 11.2 mGy for ages 10–14 years, and 15.6 mGy for patients 15 years or older. Conclusion Local DRLs for pediatric neck CT were established based on age, weight, and WED across nine university hospitals in South Korea.

Purpose: In this study, we investigated the effect of bisphenol-A (BPA) and its major analogs, bisphenol-F (BPF), and bisphenol-S (BPS), on spermatogonial stem cells (SSCs) populations using in vitro SSC culture and in vivo transplantation models. Materials and Methods: SSCs enriched from 6- to 8-day-old C57BL/6-eGFP+ male mice testes were treated with varying concentrations of bisphenols for 7 days to examine bisphenol-derived cytotoxicity and changes in SSC characteristics. We utilized flow cytometry, immunocytochemistry, real-time quantitative reverse transcription-PCR, and western blot analysis. The functional alteration of SSCs was further investigated by examining donor SSC-derived spermatogenesis evaluation through in vivo transplantation and subsequent testis analysis. Results: BPF exhibited a similar inhibitory effect on SSCs as BPA, demonstrating a significant decrease in SSC survival, inhibition of proliferation, and induction of apoptosis. On the other hand, while BPS was comparatively weaker than BPA and BPF, it still showed significant SSC cytotoxicity. Importantly, SSCs exposed to BPA, BPF, and BPS exhibited a significant reduction in donor SSC-derived germ cell colonies per total number of cultured cells, indicating that, like BPA, BPF, and BPS can induce a comparable reduction in functional SSCs in the recipient animals. However, the progress of spermatogenesis, as evidenced by histochemistry and the expressions of PCNA and SSC specific markers, collectively indicates that BPA, BPF, and BPS may not adversely affect the spermatogenesis. Conclusions Our findings indicate that the major BPA substitutes, BPF and BPS, have significant cytotoxic effects on SSCs, similar to BPA. These effects may lead to a reduction in the functional self-renewal stem cell population and potential impacts on male fertility.

Background: and Purpose: Recognizing cognitive decline patterns in mild cognitive impairment (MCI) is crucial for early screening and preventive interventions. However, studies on the trajectory of individual cognitive functions in MCI are limited. Thus, the purpose of this study was to identify subtypes and stages of cognitive decline in MCI using a machine learning method. Methods: A total of 944 subjects consisting of those who were cognitively normal and those with MCI were enrolled. Fifteen neuropsychological tasks were used in the analysis.The optimal number of subtypes was determined based on the cross-validation information criterion. Fifteen stages of cognitive trajectory were estimated for each subtype. Results: The following three subtypes were identified: amnestic-verbal subtype, dysexecutive subtype, and amnestic-visual subtype. Of 723 (76.6%) subjects who had reached stage 1 at least, amnestic-verbal subtype accounted for the most (n=340, 47.0%), followed by dysexecutive subtype (n=253, 35.0%) and amnestic-visual subtype (n=130, 18%). The amnestic-verbal subtype had significantly more males (amnestic-verbal: 41.8%, dysexecutive: 31.2%, and amnestic-visual: 28.5%), younger subjects (amnestic-verbal: 72.01 years, dysexecutive: 74.43 years, and amnestic-visual: 75.06 years), higher educational years (amnestic-verbal: 11.06 years, dysexecutive: 9.53 years, and amnestic-visual: 9.79 years), lower Clinical Dementia Rating sum of boxes (amnestic-verbal: 1.40, dysexecutive: 1.61, and amnestic-visual: 1.71), and lower Korean-Instrumental Activities of Daily Living score (amnestic-verbal: 0.20, dysexecutive: 0.27, and amnestic-visual: 0.26). Conclusions Three types of MCIs were extracted using SuStaIn. Pathways of MCI deterioration could be different. The amnestic type could be bisected based on whether episodic verbal or visual memory is degraded first.

Objective: To establish local diagnostic reference levels (DRLs) for pediatric neck CT based on age, weight, and water-equivalent diameter (WED) across multiple university hospitals in South Korea. Materials and Methods: This retrospective study analyzed pediatric neck CT examinations from nine university hospitals, involving patients aged 0–18 years. Data were categorized by age, weight, and WED, and radiation dose metrics, including volume CT dose index (CTDIvol) and dose length product, were recorded. Data retrieval and analysis were conducted using a commercially available dose-management system (Radimetrics, Bayer Healthcare). Local DRLs were established following the International Commission on Radiological Protection guidelines, using the 75th percentile as the reference value. Results: A total of 1159 CT examinations were analyzed, including 169 scans from Institution 1, 132 from Institution 2, 126 from Institution 3, 129 from Institution 4, 128 from Institution 5, 105 from Institution 6, 162 from Institution 7, 127 from Institution 8, and 81 from Institution 9. Radiation dose metrics increased with age, weight, and WED, showing significant variability both within and across institutions. For patients weighing less than 10 kg, the DRL for CTDIvol was 5.2 mGy. In the 10–19 kg group, the DRL was 5.8 mGy; in the 20–39 kg group, 7.6 mGy; in the 40–59 kg group, 11.0 mGy; and for patients weighing 60 kg or more, 16.2 mGy. DRLs for CTDIvol by age groups were as follows: 5.3 mGy for infants under 1 year, 5.7 mGy for children aged 1–4 years, 7.6 mGy for ages 5–9 years, 11.2 mGy for ages 10–14 years, and 15.6 mGy for patients 15 years or older. Conclusion Local DRLs for pediatric neck CT were established based on age, weight, and WED across nine university hospitals in South Korea.

Purpose: In this study, we investigated the effect of bisphenol-A (BPA) and its major analogs, bisphenol-F (BPF), and bisphenol-S (BPS), on spermatogonial stem cells (SSCs) populations using in vitro SSC culture and in vivo transplantation models. Materials and Methods: SSCs enriched from 6- to 8-day-old C57BL/6-eGFP+ male mice testes were treated with varying concentrations of bisphenols for 7 days to examine bisphenol-derived cytotoxicity and changes in SSC characteristics. We utilized flow cytometry, immunocytochemistry, real-time quantitative reverse transcription-PCR, and western blot analysis. The functional alteration of SSCs was further investigated by examining donor SSC-derived spermatogenesis evaluation through in vivo transplantation and subsequent testis analysis. Results: BPF exhibited a similar inhibitory effect on SSCs as BPA, demonstrating a significant decrease in SSC survival, inhibition of proliferation, and induction of apoptosis. On the other hand, while BPS was comparatively weaker than BPA and BPF, it still showed significant SSC cytotoxicity. Importantly, SSCs exposed to BPA, BPF, and BPS exhibited a significant reduction in donor SSC-derived germ cell colonies per total number of cultured cells, indicating that, like BPA, BPF, and BPS can induce a comparable reduction in functional SSCs in the recipient animals. However, the progress of spermatogenesis, as evidenced by histochemistry and the expressions of PCNA and SSC specific markers, collectively indicates that BPA, BPF, and BPS may not adversely affect the spermatogenesis. Conclusions Our findings indicate that the major BPA substitutes, BPF and BPS, have significant cytotoxic effects on SSCs, similar to BPA. These effects may lead to a reduction in the functional self-renewal stem cell population and potential impacts on male fertility.

Objective: To establish local diagnostic reference levels (DRLs) for pediatric neck CT based on age, weight, and water-equivalent diameter (WED) across multiple university hospitals in South Korea. Materials and Methods: This retrospective study analyzed pediatric neck CT examinations from nine university hospitals, involving patients aged 0–18 years. Data were categorized by age, weight, and WED, and radiation dose metrics, including volume CT dose index (CTDIvol) and dose length product, were recorded. Data retrieval and analysis were conducted using a commercially available dose-management system (Radimetrics, Bayer Healthcare). Local DRLs were established following the International Commission on Radiological Protection guidelines, using the 75th percentile as the reference value. Results: A total of 1159 CT examinations were analyzed, including 169 scans from Institution 1, 132 from Institution 2, 126 from Institution 3, 129 from Institution 4, 128 from Institution 5, 105 from Institution 6, 162 from Institution 7, 127 from Institution 8, and 81 from Institution 9. Radiation dose metrics increased with age, weight, and WED, showing significant variability both within and across institutions. For patients weighing less than 10 kg, the DRL for CTDIvol was 5.2 mGy. In the 10–19 kg group, the DRL was 5.8 mGy; in the 20–39 kg group, 7.6 mGy; in the 40–59 kg group, 11.0 mGy; and for patients weighing 60 kg or more, 16.2 mGy. DRLs for CTDIvol by age groups were as follows: 5.3 mGy for infants under 1 year, 5.7 mGy for children aged 1–4 years, 7.6 mGy for ages 5–9 years, 11.2 mGy for ages 10–14 years, and 15.6 mGy for patients 15 years or older. Conclusion Local DRLs for pediatric neck CT were established based on age, weight, and WED across nine university hospitals in South Korea.

Purpose: In this study, we investigated the effect of bisphenol-A (BPA) and its major analogs, bisphenol-F (BPF), and bisphenol-S (BPS), on spermatogonial stem cells (SSCs) populations using in vitro SSC culture and in vivo transplantation models. Materials and Methods: SSCs enriched from 6- to 8-day-old C57BL/6-eGFP+ male mice testes were treated with varying concentrations of bisphenols for 7 days to examine bisphenol-derived cytotoxicity and changes in SSC characteristics. We utilized flow cytometry, immunocytochemistry, real-time quantitative reverse transcription-PCR, and western blot analysis. The functional alteration of SSCs was further investigated by examining donor SSC-derived spermatogenesis evaluation through in vivo transplantation and subsequent testis analysis. Results: BPF exhibited a similar inhibitory effect on SSCs as BPA, demonstrating a significant decrease in SSC survival, inhibition of proliferation, and induction of apoptosis. On the other hand, while BPS was comparatively weaker than BPA and BPF, it still showed significant SSC cytotoxicity. Importantly, SSCs exposed to BPA, BPF, and BPS exhibited a significant reduction in donor SSC-derived germ cell colonies per total number of cultured cells, indicating that, like BPA, BPF, and BPS can induce a comparable reduction in functional SSCs in the recipient animals. However, the progress of spermatogenesis, as evidenced by histochemistry and the expressions of PCNA and SSC specific markers, collectively indicates that BPA, BPF, and BPS may not adversely affect the spermatogenesis. Conclusions Our findings indicate that the major BPA substitutes, BPF and BPS, have significant cytotoxic effects on SSCs, similar to BPA. These effects may lead to a reduction in the functional self-renewal stem cell population and potential impacts on male fertility.

Purpose: To investigate whether a new phospholipid-releasing soft contact lens can improve symptoms of dry eyes. Methods: The study used 2.5-3.0 kg New Zealand rabbits including both normal non-dry eye rabbits and dry eye rabbits, the latter having undergone electrocauterization of the meibomian glands to block the gland orifices. Each rabbit wore a control contact lens on one eye and a phospholipid-releasing contact lens on the other eye daily. Phospholipid-releasing and control contact lenses were provided by NEOVISION Co., Ltd. The parameters assessed included tear film break-up time, tear osmolarity, ocular surface staining, and central corneal thickness. After the experiment, the rabbits were euthanized and their conjunctival tissue was stained with Periodic Acid Schiff (PAS) to observe conjunctival goblet cells. Results: In both dry eye and normal non-dry eye rabbits, tear film break-up time was longer and tear osmolarity was lower when using the phospholipid-releasing contact lens compared to the control contact lens. The ocular surface remained unstained in normal non-dry eye rabbits while staining was observed in dry eye rabbits. There was no significant difference in central corneal thickness between the control and phospholipid-releasing contact lenses in either group. PAS staining showed no difference in conjunctival goblet cell density between the two lens types in normal non-dry eye rabbits. However, in dry eye rabbits, the conjunctival goblet cell density tended to be slightly higher with the phospholipid-releasing contact lens compared to the control lens. Conclusions Phospholipid-releasing contact lenses may help reduce dry eye symptoms and minimize contact lens-related complications by stabilizing the tear film and lowering tear osmolarity.

This study aimed to identify the factors affecting dry eye syndrome and quality of life (QoL) among college students. Methods: This cross-sectional study administered a descriptive survey to 184 college students across Korea. Data collection was conducted from August 27 to 28, 2024, using an online survey platform (Google Forms). The self-reported survey comprised the Health-Related Quality of Life Instrument with 8 Items scale, the Dry Eye Questionnaire 5, and the Ocular Surface Disease Index. Data analysis was performed using SPSS version 27.0. Results: The participants had a mean age of 21.37 (standard deviation 1.96) years. Regression analysis identified sleep satisfaction, vision-related functions, and dry eye symptoms as statistically significant predictors of QoL, accounting for 18.4% of the variance (F = 14.71, p < .001). Dry eye symptoms were significantly influenced by the use of artificial tears, vision-related functions, and environmental factors, which accounted for 41.3% of the variance (F = 43.93, p < .001). Additionally, significant determinants of ocular surface disease included the use of vision correction tools, the presence of ophthalmic diseases, sleep satisfaction, and dry eye symptoms. These factors explained 45.7% of the variance, confirming the model's robustness (F = 31.84, p < .001). Conclusion: It is necessary to identify strategies to alleviate dry eye syndrome in college students and develop comprehensive prevention and management programs to improve their QoL.

This study aimed to identify the factors affecting dry eye syndrome and quality of life (QoL) among college students. Methods: This cross-sectional study administered a descriptive survey to 184 college students across Korea. Data collection was conducted from August 27 to 28, 2024, using an online survey platform (Google Forms). The self-reported survey comprised the Health-Related Quality of Life Instrument with 8 Items scale, the Dry Eye Questionnaire 5, and the Ocular Surface Disease Index. Data analysis was performed using SPSS version 27.0. Results: The participants had a mean age of 21.37 (standard deviation 1.96) years. Regression analysis identified sleep satisfaction, vision-related functions, and dry eye symptoms as statistically significant predictors of QoL, accounting for 18.4% of the variance (F = 14.71, p < .001). Dry eye symptoms were significantly influenced by the use of artificial tears, vision-related functions, and environmental factors, which accounted for 41.3% of the variance (F = 43.93, p < .001). Additionally, significant determinants of ocular surface disease included the use of vision correction tools, the presence of ophthalmic diseases, sleep satisfaction, and dry eye symptoms. These factors explained 45.7% of the variance, confirming the model's robustness (F = 31.84, p < .001). Conclusion: It is necessary to identify strategies to alleviate dry eye syndrome in college students and develop comprehensive prevention and management programs to improve their QoL.