BACKGROUND: The purpose of this study was to explore the factors related to internet addiction in college students in Korea. METHODS: This study was a cross-sectional survey of college students in Seoul, and data was collected through self-report questionnaires. Data was analyzed by one-way analysis of variance, Fisher's exact test, Kruskal-Wallis rank test, and ordinary logistic regression analysis. RESULTS: In the ordinary logistic regression analysis, the factors related to a higher risk of internet addiction were lower frequency of exercise (P=0.017), lower level of self-control (P<0.001), higher level of stress (P<0.001), living with parents (P=0.011), using the internet for extended periods of time (P<0.001), and using the internet in their own rooms (P<0.001). CONCLUSIONS: Our results suggest that exercise, self-control, stress, living with parents, and duration and place of internet use are associated with internet addiction in college students. This information can be used to design methods for preventing internet addiction. More specific studies on internet addiction in college students are needed.
Behavior, Addictive ; Cross-Sectional Studies ; Humans ; Hypogonadism ; Internet ; Logistic Models ; Mitochondrial Diseases ; Ophthalmoplegia ; Parents ; Surveys and Questionnaires

Although various functions of CD99 have been reported, such as apoptosis and homotypic aggregation of thymocyte and transendothelial migration of immune cells, biochemical/molecular natures of CD99 are still elusive. Using mouse CD99 gene, we show that CD99 forms homodimer through its extracellular domain. Expression of mouse CD99 is up-regulated on T cells after CD3-mediated activation, like the case for human CD99. The potential of CD99 to form homodimer was tested with a recently developed bimoleular fluorescence complementation analysis (BiFC). In BiFC analysis, the dimerization-induced fluorescence was strong near the perinuclear region and was faded at the cell membrane. However, surface expression of CD99 was still detected by flow cytometry, suggesting that CD99 either in monomer form or in association with other molecules exists on the cell surface. In BiFC analysis using CD99 mutants with its extracellular, transmembrane, or cytosolic domains changed to corresponding human CD4 domains, the mutant replaced with human CD4-extracellular domain did not produce fluorescence. Purified soluble CD99-Fc fusion proteins bound to CD99-Fc immobilized onto the gold sensor chip in surface plasmon resonance analysis, confirming that the extracellular domain was responsible for dimer formation. Intracytoplasmic staining for CD99 expression in the thymocytes and mature T cells showed that most of the cells, even the cells with low surface level of CD99, contained the molecule inside the cell. Our results suggest that majority of CD99 homodimers may exit in the cell and be exported to the cell surface, dissociating from each other, after a certain regulatory signal is delivered.
Animals ; Antigens, CD/chemistry/*isolation & purification ; Cell Adhesion Molecules/chemistry/*isolation & purification ; Flow Cytometry ; *Fluorescence ; Luminescent Measurements/*methods ; Mice ; Molecular Biology/*methods ; T-Lymphocytes/immunology

Purpose: In response to the surge in coronavirus disease 2019 (COVID-19) omicron variant cases, we have implemented preemptive testing for preschool and school. The purpose is to quickly detect COVID-19 cases using a rapid antigen test (RAT) kit so that normal school activities can continue. Methods: The results entered in The Healthcare Self-Test App were merged with the information on the status of confirmed cases in the COVID-19 Information Management System by Korea Disease Control and Prevention Agency (KDCA) for preschool and school of students and staffs March 2 to May 1, 2022 to analyze the RAT positive rate and positive predictive value of RAT. Results: In preschool and school 19,458,575 people were tested, weekly RAT positive rate ranged from 1.10% to 5.90%, positive predictive value of RAT ranged from 86.42% to 93.18%.By status, RAT positive rate ranged from 1.13% to 6.16% for students, 0.99% to 3.93% for staffs, positive predictive value of RAT ranged from 87.19% to 94.03% for students, 77.55% to 83.10% for staffs. RAT positive rate by symptoms ranged from 76.32% to 88.02% for those with symptoms and 0.34% to 1.11% for those without symptoms. As a result of preschool and school RAT, 943,342 confirmed cases were preemptively detected, before infection spread in preschool and school. Conclusions RAT was well utilized to detect confirmed cases at an early stage, reducing the risk of transmission to minimize the educational gap in preschool and school. To compensate for the limitations of RAT, further research should continue to reevaluate the performance of RAT as new strains of viruses continue to emerge. We will have to come up with various ways to utilize it, such as performing periodic and repeated RAT and parallel polymerase chain reaction.

Purpose: In response to the surge in coronavirus disease 2019 (COVID-19) omicron variant cases, we have implemented preemptive testing for preschool and school. The purpose is to quickly detect COVID-19 cases using a rapid antigen test (RAT) kit so that normal school activities can continue. Methods: The results entered in The Healthcare Self-Test App were merged with the information on the status of confirmed cases in the COVID-19 Information Management System by Korea Disease Control and Prevention Agency (KDCA) for preschool and school of students and staffs March 2 to May 1, 2022 to analyze the RAT positive rate and positive predictive value of RAT. Results: In preschool and school 19,458,575 people were tested, weekly RAT positive rate ranged from 1.10% to 5.90%, positive predictive value of RAT ranged from 86.42% to 93.18%.By status, RAT positive rate ranged from 1.13% to 6.16% for students, 0.99% to 3.93% for staffs, positive predictive value of RAT ranged from 87.19% to 94.03% for students, 77.55% to 83.10% for staffs. RAT positive rate by symptoms ranged from 76.32% to 88.02% for those with symptoms and 0.34% to 1.11% for those without symptoms. As a result of preschool and school RAT, 943,342 confirmed cases were preemptively detected, before infection spread in preschool and school. Conclusions RAT was well utilized to detect confirmed cases at an early stage, reducing the risk of transmission to minimize the educational gap in preschool and school. To compensate for the limitations of RAT, further research should continue to reevaluate the performance of RAT as new strains of viruses continue to emerge. We will have to come up with various ways to utilize it, such as performing periodic and repeated RAT and parallel polymerase chain reaction.

Purpose: In response to the surge in coronavirus disease 2019 (COVID-19) omicron variant cases, we have implemented preemptive testing for preschool and school. The purpose is to quickly detect COVID-19 cases using a rapid antigen test (RAT) kit so that normal school activities can continue. Methods: The results entered in The Healthcare Self-Test App were merged with the information on the status of confirmed cases in the COVID-19 Information Management System by Korea Disease Control and Prevention Agency (KDCA) for preschool and school of students and staffs March 2 to May 1, 2022 to analyze the RAT positive rate and positive predictive value of RAT. Results: In preschool and school 19,458,575 people were tested, weekly RAT positive rate ranged from 1.10% to 5.90%, positive predictive value of RAT ranged from 86.42% to 93.18%.By status, RAT positive rate ranged from 1.13% to 6.16% for students, 0.99% to 3.93% for staffs, positive predictive value of RAT ranged from 87.19% to 94.03% for students, 77.55% to 83.10% for staffs. RAT positive rate by symptoms ranged from 76.32% to 88.02% for those with symptoms and 0.34% to 1.11% for those without symptoms. As a result of preschool and school RAT, 943,342 confirmed cases were preemptively detected, before infection spread in preschool and school. Conclusions RAT was well utilized to detect confirmed cases at an early stage, reducing the risk of transmission to minimize the educational gap in preschool and school. To compensate for the limitations of RAT, further research should continue to reevaluate the performance of RAT as new strains of viruses continue to emerge. We will have to come up with various ways to utilize it, such as performing periodic and repeated RAT and parallel polymerase chain reaction.

PURPOSE: Internal mammary lymph node (IMN) involvement is associated with poor prognosis in breast cancer. This study investigated the treatment outcomes of initial clinically IMN-positive breast cancer patients who received adjuvant radiotherapy (RT), including IMN irradiation, following primary breast surgery. MATERIALS AND METHODS: We retrospectively reviewed data of 95 breast cancer patients with clinically detected IMNs at diagnosis treated with surgery and RT between June 2009 and December 2015. Patients received adjuvant RT to the whole breast/chest wall and regional lymph node (axillary, internal mammary, and supraclavicular) areas. Twelve patients received an additional boost to the IMN area. RESULTS: The median follow-up was 43.2 months (range, 4.5 to 100.5 months). Among 77 patients who received neoadjuvant chemotherapy, 52 (67.5%) showed IMN normalization and 19 (24.6%) showed a partial response to IMN. There were 3 and 24 cases of IMN failure and any recurrence, respectively. The 5-year IMN failure-free survival, disease-free survival (DFS), and overall survival (OS) were 96%, 70%, and 84%, respectively. IMN failure-free survival was significantly affected by resection margin status (97.7% if negative, 87.5% for close or positive margins; p = 0.009). All three patients with IMN failure had initial IMN size ≥1 cm and did not receive IMN boost irradiation. The median age of the three patients was 31 years, and all had hormone receptor-negative tumors. CONCLUSION: RT provides excellent IMN control without the support of IMN surgery. Intensity-modulated radiotherapy, including IMN boost for breast cancer patients, is a safe and effective technique for regional lymph node irradiation.
Breast Neoplasms ; Breast ; Diagnosis ; Disease-Free Survival ; Drug Therapy ; Follow-Up Studies ; Humans ; Lymph Nodes ; Prognosis ; Radiotherapy ; Radiotherapy, Adjuvant ; Radiotherapy, Intensity-Modulated ; Recurrence ; Retrospective Studies

Purpose: This study aimed to determine the role of local ablative radiotherapy (LART) in oligometastatic/oligoprogressive lung adenocarcinoma. Materials and Methods: Patients (n=176) with oligometastatic lung adenocarcinoma treated with LART were identified, and those treated with LART at the initial diagnosis of synchronous oligometastatic disease (OMD group) or treated with LART when they presented with repeat oligoprogression (OPD group) were included. Results: In the OMD group (n=54), the 1- and 3-year progression-free survival (PFS) were 50.9% and 22.5%, respectively, whereas the 1- and 3-year overall survival in the OPD group were 75.9% and 58.1%, respectively. Forty-one patients (75.9%) received LART at all gross disease sites. Tyrosine kinase inhibitor (TKI) use and all-metastatic site LART were significant predictors of higher PFS (p=0.018 and p=0.046, respectively). In patients treated with TKIs at the time of LART (n=23) and those treated with all-metastatic site LART, the 1-year PFS was 86.7%, while that of patients not treated with all-metastatic site LART was 37.5% (p=0.006). In the OPD group (n=122), 67.2% of the patients (n=82) maintained a systemic therapy regimen after LART. The cumulative incidence of changing systemic therapy was 39.6%, 62.9%, and 78.5% at 6 months, 1 year, and 2 years after LART, respectively. Conclusion Aggressive LART can be an option to improve survival in patients with oligometastatic disease. Patients with synchronous oligometastatic disease receiving TKI and all-metastatic site LART may have improved PFS. In patients with repeat oligoprogression, LART might potentially extend survival by delaying the need to change the systemic treatment regimen.

Purpose: This study aimed to assess the feasibility and safety of administering intraoperative radiotherapy (IORT) as a boost during breast-conserving surgery (BCS) following neoadjuvant chemotherapy for patients at high risk of breast cancer recurrence. Materials and Methods: Patients who underwent neoadjuvant chemotherapy received a single 20-Gy dose of IORT during BCS, followed by external beam radiotherapy 4–6 weeks after surgery. Results: The median follow-up duration was 31.0 months (range, 18.0–59.0 months). Initial tumor sizes had a median of 2.6 cm (range: 0.8–5.3 cm), reducing to 0.3 cm (range: 0–4.0 cm) after neoadjuvant chemotherapy. The most common neoadjuvant chemotherapy regimen was doxorubicin and cyclophosphamide, followed by paclitaxel (n=42, 73.7%). Among 57 patients who received neoadjuvant chemotherapy before BCS and IORT, 2 patients (3.5%) required secondary surgery to achieve negative resection margins due to initially positive margins. Regional lymph node irradiation was performed in 37 (64.9%) patients. There was no grade 3 or higher adverse events, with 4 patients (7.0%) experiencing grade 2 acute radiation dermatitis and 3 (5.3%) having less than grade 2 breast edema. Binary correlation analysis did not reveal statistically significant associations between applicator size or radiation therapy modality and the risk of treatment-related toxicity. Furthermore, chi-square analysis showed that the grade of treatment-related toxicity was not associated with the fractionated regimen (p=0.375). Conclusion Most patients successfully received IORT as a tumor bed boost after neoadjuvant chemotherapy. Thus, IORT may be a safe and feasible option for patients with advanced-stage breast cancer receiving neoadjuvant chemotherapy.

Purpose: The details of breast reconstruction and radiation therapy (RT) vary between institutions; therefore, we sought to investigate the practice patterns of radiation oncologists who specialize in breast cancer. Materials and Methods: We identified the practice patterns and inter-hospital variations from a multi-center cohort of women with breast cancer who underwent post-mastectomy RT (PMRT) to the reconstructed breast at 16 institutions between 2015 and 2016. The institutions were requested to contour the target volume and produce RT plans for one representative case with five different clinical scenarios and answer questionnaires which elicited infrastructural information. We assessed the inter-institutional variations in RT in terms of the target, normal organ delineation, and dose-volume histograms. Results: Three hundred fourteen patients were included; 99% of them underwent immediate reconstruction. The most irradiated material was tissue expander (36.9%) followed by transverse rectus abdominis musculocutaneous flap (23.9%) and silicone implant (12.1%). In prosthetic-based reconstruction with tissue expander, most patients received PMRT following partial deflation. Conventional fractionation and hypofractionation RT were used in 66.6% and 33.4% patients, respectively (commonest: 40.05 Gy in 15 fractions [17.5%]). Furthermore, 15.6% of the patients received boost RT and 53.5% were treated with bolus. Overall, 15 physicians responded to the questionnaires and six submitted their contours and RT plans. There was a significant variability in target delineations and RT plans between physicians, and between clinical scenarios. Conclusion Adjuvant RT following post-mastectomy reconstruction has become a common practice in Korea. The details vary significantly between institutions, which highlights an urgent need for standard protocol in this clinical setting.

Purpose: The details of breast reconstruction and radiation therapy (RT) vary between institutions; therefore, we sought to investigate the practice patterns of radiation oncologists who specialize in breast cancer. Materials and Methods: We identified the practice patterns and inter-hospital variations from a multi-center cohort of women with breast cancer who underwent post-mastectomy RT (PMRT) to the reconstructed breast at 16 institutions between 2015 and 2016. The institutions were requested to contour the target volume and produce RT plans for one representative case with five different clinical scenarios and answer questionnaires which elicited infrastructural information. We assessed the inter-institutional variations in RT in terms of the target, normal organ delineation, and dose-volume histograms. Results: Three hundred fourteen patients were included; 99% of them underwent immediate reconstruction. The most irradiated material was tissue expander (36.9%) followed by transverse rectus abdominis musculocutaneous flap (23.9%) and silicone implant (12.1%). In prosthetic-based reconstruction with tissue expander, most patients received PMRT following partial deflation. Conventional fractionation and hypofractionation RT were used in 66.6% and 33.4% patients, respectively (commonest: 40.05 Gy in 15 fractions [17.5%]). Furthermore, 15.6% of the patients received boost RT and 53.5% were treated with bolus. Overall, 15 physicians responded to the questionnaires and six submitted their contours and RT plans. There was a significant variability in target delineations and RT plans between physicians, and between clinical scenarios. Conclusion Adjuvant RT following post-mastectomy reconstruction has become a common practice in Korea. The details vary significantly between institutions, which highlights an urgent need for standard protocol in this clinical setting.