1.Association between working ≥10 hours per day and satisfaction with work environment among wage workers in Korea: a cross-sectional study using data from the 7th Korean Working Conditions Survey
Rae-Yun KIM ; Dong-Woo KIM ; Yoon-Soo JANG ; Na-Rae LEE ; June-Hee LEE ; Kyung-Jae LEE
Annals of Occupational and Environmental Medicine 2026;38(1):e9-
Background:
Long working hours have been associated with adverse physical and mental health outcomes; however, evidence regarding their relationship with satisfaction with work environment remains limited, particularly when long working hours are defined using a specific daily threshold. This study examined the association between working ≥10 hours per day and satisfaction with work environment among Korean wage workers, focusing on the cumulative number of such workdays per month.
Methods:
This cross-sectional study analyzed data from the 7th Korean Working Conditions Survey. A total of 24,269 wage workers aged ≥18 years were included after excluding self-employed workers, unpaid family workers, shift workers, and respondents with missing data. Working ≥10 hours per day was categorized as 0, 1–9, and ≥10 days per month. Satisfaction with work environment was categorized as satisfied or dissatisfied. Multiple logistic regression analyses were conducted to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for dissatisfaction with work environment according to the number of long working days, adjusting for demographic and occupational characteristics.
Results:
Compared with workers who did not work ≥10 hours per day, those who worked 1–9 days and ≥10 days per month showed progressively higher levels of dissatisfaction with work environment. After adjustment for demographic and occupational factors, the odds of dissatisfaction with work environment were significantly higher among workers who worked ≥10 hours per day for 1–9 days per month (OR: 1.380; 95% CI: 1.145–1.665) and ≥10 days per month (OR: 2.106; 95% CI: 1.627–2.725), demonstrating a dose–response relationship.
Conclusions
Among the analytic sample of Korean wage workers included in this study, working ≥10 hours per day was associated with greater dissatisfaction with work environment, with a dose–response pattern according to the number of long working days per month.
2.Catalpa bignonioides extract improves exercise performance through regulation of growth and metabolism in skeletal muscles
Hoibin Jeong ; Dong-joo Lee ; Sung-Pil Kwon ; SeonJu Park ; Song-Rae Kim ; Seung Hyun Kim ; Jae-Il Park ; Deug-chan Lee ; Kyung-Min Choi ; WonWoo Lee ; Ji-Won Park ; Bohyun Yun ; Su-Hyeon Cho ; Kil-Nam Kim
Asian Pacific Journal of Tropical Biomedicine 2024;14(2):47-54
Objective: To evaluate the effects of Catalpa bignonioides fruit extract on the promotion of muscle growth and muscular capacity in vitro and in vivo. Methods: Cell viability was measured using the 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide assay. Cell proliferation was assessed using a 5-bromo-2’-deoxyuridine (BrdU) assay kit. Western blot analysis was performed to determine the protein expressions of related factors. The effects of Catalpa bignonioides extract were investigated in mice using the treadmill exhaustion test and whole-limb grip strength assay. Chemical composition analysis was performed using high-performance liquid chromatography (HPLC). Results: Catalpa bignonioides extract increased the proliferation of C2C12 mouse myoblasts by activating the Akt/mTOR signaling pathway. It also induced metabolic changes, increasing the number of mitochondria and glucose metabolism by phosphorylating adenosine monophosphate-activated protein kinase. In an in vivo study, the extract-treated mice showed improved motor abilities, such as muscular endurance and grip strength. Additionally, HPLC analysis showed that vanillic acid may be the main component of the Catalpa bignonioides extract that enhanced muscle strength. Conclusions: Catalpa bignonioides improves exercise performance through regulation of growth and metabolism in skeletal muscles, suggesting its potential as an effective natural agent for improving muscular strength.
3.The Multifaceted Clinical Characteristics of Congenital Cytomegalovirus Infection: From Pregnancy to Long-Term Outcomes
Yejin KIM ; Yoo-min KIM ; Doo Ri KIM ; Han Gyeol KIM ; Ji-Hee SUNG ; Suk-Joo CHOI ; Soo-young OH ; Yae-Jean KIM ; Yun Sil CHANG ; Dongsub KIM ; Jung-Sun KIM ; Il Joon MOON ; Cheong-Rae ROH
Journal of Korean Medical Science 2023;38(32):e249-
Background:
The aim of this study was to capture multifaceted clinical characteristics of congenital cytomegalovirus (CMV) infection from diagnosis to treatment using a multidisciplinary approach including obstetrics, pediatrics, pathology, and otorhinolaryngology-head and neck surgery.
Methods:
This is a retrospective study including 30 consecutive cases of congenital CMV infection that were diagnosed at a single tertiary hospital located in Seoul, Korea from January 2009 to December 2020. Congenital CMV infection was defined as a positive result by polymerase chain reaction from urine, saliva or cerebrospinal fluid or positive CMV IgM from neonatal blood sampled within 3 weeks after birth. All cases were analyzed with respect to whole clinical characteristics from diagnosis to treatment of congenital CMV by a multidisciplinary approach including prenatal sonographic findings, maternal immune status regarding CMV infection, detailed placental pathology, neonatal clinical manifestation, auditory brainstem response test, and antiviral treatment (ganciclovir or valganciclovir). Long-term outcomes including developmental delay and hearing loss were also investigated.
Results:
The total number of births during the study period in our institution was 19,385, with the prevalence of congenital infection estimated to be 0.15%. Among 30 cases of congenital CMV, the median gestational age at delivery was 32.2 weeks [range, 22.6–40.0] and 66.7% of these infants were delivered preterm at less than 37 weeks. Suspected fetal growth restriction was the most common prenatal ultrasound finding (50%) followed by ventriculomegaly (17.9%) and abnormal placenta (17.9%), defined as thick placenta with calcification. No abnormal findings on ultrasound examination were observed in one-third of births. Maternal CMV serology tests were conducted in only 8 cases, and one case each of positive and equivocal IgM were found. The most common placental pathologic findings were chronic villitis (66.7%) and calcification (63.0%), whereas viral inclusions were identified in only 22.2%. The most common neonatal manifestations were jaundice (58.6%) followed by elevation of aspartate aminotransferase (55.2%) and thrombocytopenia (51.7%). After excluding cases for which long-term outcomes were unavailable due to death (n = 4) or subsequent follow up loss (n = 3), developmental delay was confirmed in 43.5% of infants (10/23), and hearing loss was confirmed in 42.9% (9/21) during the follow-up period. In our cohort, 56.7% (17/30) of neonates were treated for congenital CMV with ganciclovir or valganciclovir.
Conclusion
Our data show that prenatal findings including maternal serologic tests and ultrasound have limited ability to detect congenital CMV in Korea. Given that CMV is associated with high rates of developmental delay and hearing loss in infants, there is an urgent need to develop specific strategies for the definite diagnosis of congenital CMV infection during the perinatal period by a multidisciplinary approach to decrease the risks of neurologic impairment and hearing loss through early antiviral treatment.
4.Antenatal Magnesium Sulfate Is Not Associated With Improved Long-Term Neurodevelopment and Growth in Very Low Birth Weight Infants
Ga Won JEON ; So Yoon AHN ; Su Min KIM ; Misun YANG ; Se In SUNG ; Ji-Hee SUNG ; Soo-young OH ; Cheong-Rae ROH ; Suk-Joo CHOI ; Yun Sil CHANG
Journal of Korean Medical Science 2023;38(44):e350-
Background:
Though antenatal magnesium sulfate (MgSO4 ) is widely used for fetal neuroprotection, suspicions about the long-term neuroprotection of antenatal MgSO4 have been raised.
Methods:
We investigated short- and long-term outcomes of antenatal MgSO4 use for 468 infants weighing < 1,500 g with a gestational age of 24–31 weeks.
Results:
Short-term morbidities and the risk of developmental delay, hearing loss, and cerebral palsy at a corrected age of 18–24 months and 3 years of age did not decrease in the MgSO4 group (infants who were exposed to MgSO4 for any purpose) or neuroprotection group (infants who were exposed to MgSO4 for fetal neuroprotection) compared with the control group (infants who were not exposed to MgSO4 ). The z-scores of weight, height, and head circumference did not increase in the MgSO4 group or neuroprotection group compared with the control group.
Conclusion
Antenatal MgSO4 including MgSO4 for neuroprotection did not have beneficial effects on long-term neurodevelopmental and growth outcomes.
5.Differential Expression of NME4 in Trophoblast Stem-Like Cells and Peripheral Blood Mononuclear Cells of Normal Pregnancy and Preeclampsia
Ji Hea YU ; Yun Ji JUNG ; Myung-Sun KIM ; Sung-Rae CHO ; Young-Han KIM
Journal of Korean Medical Science 2023;38(16):e128-
Background:
Preeclampsia (PE) is known to arise from insufficient trophoblast invasion as uterine spiral arteries lack remodeling. A significant reduction in placental perfusion induces an ischemic placental microenvironment due to reduced oxygen delivery to the placenta and fetus, leading to oxidative stress. Mitochondria are involved in the regulation of cellular metabolism and the production of reactive oxygen species (ROS). NME/NM23 nuceloside diphosphate kinase 4 (NME4) gene is known to have the ability to supply nucleotide triphosphate and deoxynucleotide triphosphate for replication and transcription of mitochondria. Our study aimed to investigate changes in NME4 expression in PE using trophoblast stem-like cells (TSLCs) from induced pluripotent stem cells (iPSCs) as a model of early pregnancy and peripheral blood mononuclear cells (PBMNCs) as a model of late preterm pregnancy.
Methods:
Transcriptome analysis using TSLCs was performed to identify the candidate gene associated with the possible pathophysiology of PE. Then, the expression of NME4 associated with mitochondrial function, p53 associated with cell death, and thioredoxin (TRX) linked to ROS were investigated through qRT-PCR, western blotting and deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL) assay.
Results:
In patients with PE, NME4 was significantly downregulated in TSLCs but upregulated in PBMNCs. p53 was shown to be upregulated in TSLCs and PBMNCs of PE. In addition, western blot analysis confirmed that TRX expression had the tendency to increase in TSLCs of PE. Similarly, TUNEL analysis confirmed that the dead cells were higher in PE than in normal pregnancy.
Conclusion
Our study showed that the expression of the NME4 differed between models of early and late preterm pregnancy of PE, and suggests that this expression pattern may be a potential biomarker for early diagnosis of PE.
6.Medial Arterial Calcification and the Risk of Amputation of Diabetic Foot Ulcer in Patients With Diabetic Kidney Disease
Joon Myeong SO ; Ji Ho PARK ; Jin Gyeong KIM ; Il Rae PARK ; Eun Yeong HA ; Seung Min CHUNG ; Jun Sung MOON ; Chul Hyun PARK ; Woo-Sung YUN ; Tae-Gon KIM ; Woong KIM ; Ji Sung YOON ; Kyu Chang WON ; Hyoung Woo LEE
Journal of Korean Medical Science 2023;38(21):e160-
We assessed the risk factors for major amputation of diabetic foot ulcers (DFUs) in patients with diabetic kidney disease (DKD) stages 3b–5. For DFU assessment, in addition to DFU location and presence of infection, ischemia, and neuropathy, vascular calcification was assessed using the medial arterial calcification (MAC) score. Of 210 patients, 26 (12.4%) underwent major amputations. Only the location and extension of DFU, represented by Texas grade differed between the minor and major amputation groups. However, after adjusting for covariates, ulcer location of mid- or hindfoot (vs. forefoot, odds ratio [OR] = 3.27), Texas grades 2 or 3 (vs. grade 0, OR = 5.78), and severe MAC (vs. no MAC, OR = 4.46) was an independent risk factor for major amputation (all P < 0.05). The current use of antiplatelets was a possible protective factor for major amputations (OR = 0.37, P = 0.055). In conclusion, DFU with severe MAC is associated with major amputation in patients with DKD.
7.The Korean Society for Neuro-Oncology (KSNO) Guideline for the Management of Brain Tumor Patients During the Crisis Period: A Consensus Survey About Specific Clinical Scenarios (Version 2023.1)
Min-Sung KIM ; Se-Il GO ; Chan Woo WEE ; Min Ho LEE ; Seok-Gu KANG ; Kyeong-O GO ; Sae Min KWON ; Woohyun KIM ; Yun-Sik DHO ; Sung-Hye PARK ; Youngbeom SEO ; Sang Woo SONG ; Stephen AHN ; Hyuk-Jin OH ; Hong In YOON ; Sea-Won LEE ; Joo Ho LEE ; Kyung Rae CHO ; Jung Won CHOI ; Je Beom HONG ; Kihwan HWANG ; Chul-Kee PARK ; Do Hoon LIM ;
Brain Tumor Research and Treatment 2023;11(2):133-139
Background:
During the coronavirus disease 2019 (COVID-19) pandemic, there was a shortage of medical resources and the need for proper treatment guidelines for brain tumor patients became more pressing. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future. As part II of the guideline, this consensus survey is to suggest management options in specific clinical scenarios during the crisis period.
Methods:
The KSNO Guideline Working Group consisted of 22 multidisciplinary experts on neuro-oncology in Korea. In order to confirm a consensus reached by the experts, opinions on 5 specific clinical scenarios about the management of brain tumor patients during the crisis period were devised and asked. To build-up the consensus process, Delphi method was employed.
Results:
The summary of the final consensus from each scenario are as follows. For patients with newly diagnosed astrocytoma with isocitrate dehydrogenase (IDH)-mutant and oligodendroglioma with IDH-mutant/1p19q codeleted, observation was preferred for patients with low-risk, World Health Organization (WHO) grade 2, and Karnofsky Performance Scale (KPS) ≥60, while adjuvant radiotherapy alone was preferred for patients with high-risk, WHO grade 2, and KPS ≥60. For newly diagnosed patients with glioblastoma, the most preferred adjuvant treatment strategy after surgery was radiotherapy plus temozolomide except for patients aged ≥70 years with KPS of 60 and unmethylated MGMT promoters. In patients with symptomatic brain metastasis, the preferred treatment differed according to the number of brain metastasis and performance status. For patients with newly diagnosed atypical meningioma, adjuvant radiation was deferred in patients with older age, poor performance status, complete resection, or low mitotic count.
Conclusion
It is imperative that proper medical care for brain tumor patients be sustained and provided, even during the crisis period. The findings of this consensus survey will be a useful reference in determining appropriate treatment options for brain tumor patients in the specific clinical scenarios covered by the survey during the future crisis.
8.The Korean Society for Neuro-Oncology (KSNO) Guideline for the Management of Brain Tumor Patients During the Crisis Period: A Consensus Recommendation Using the Delphi Method (Version 2023.1)
Min-Sung KIM ; Se-Il GO ; Chan Woo WEE ; Min Ho LEE ; Seok-Gu KANG ; Kyeong-O GO ; Sae Min KWON ; Woohyun KIM ; Yun-Sik DHO ; Sung-Hye PARK ; Youngbeom SEO ; Sang Woo SONG ; Stephen AHN ; Hyuk-Jin OH ; Hong In YOON ; Sea-Won LEE ; Joo Ho LEE ; Kyung Rae CHO ; Jung Won CHOI ; Je Beom HONG ; Kihwan HWANG ; Chul-Kee PARK ; Do Hoon LIM ;
Brain Tumor Research and Treatment 2023;11(2):123-132
Background:
During the coronavirus disease 2019 (COVID-19) pandemic, the need for appropriate treatment guidelines for patients with brain tumors was indispensable due to the lack and limitations of medical resources. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future.
Methods:
The KSNO Guideline Working Group was composed of 22 multidisciplinary experts on neuro-oncology in Korea. In order to reach consensus among the experts, the Delphi method was used to build up the final recommendations.
Results:
All participating experts completed the series of surveys, and the results of final survey were used to draft the current consensus recommendations. Priority levels of surgery and radiotherapy during crises were proposed using appropriate time window-based criteria for management outcome. The highest priority for surgery is assigned to patients who are life-threatening or have a risk of significant impact on a patient’s prognosis unless immediate intervention is given within 24–48 hours. As for the radiotherapy, patients who are at risk of compromising their overall survival or neurological status within 4–6 weeks are assigned to the highest priority. Curative-intent chemotherapy has the highest priority, followed by neoadjuvant/adjuvant and palliative chemotherapy during a crisis period. Telemedicine should be actively considered as a management tool for brain tumor patients during the mass infection crises such as the COVID-19 pandemic.
Conclusion
It is crucial that adequate medical care for patients with brain tumors is maintained and provided, even during times of crisis. This guideline will serve as a valuable resource, assisting in the delivery of treatment to brain tumor patients in the event of any future crisis.
9.Development of a High-Yield Isolation Protocol Optimized for the Retrieval of Active Muscle Satellite Cells from Mouse Skeletal Muscle Tissue
Hyun LEE ; Na Rae HAN ; Seong Jae KIM ; Jung Im YUN ; Seung Tae LEE
International Journal of Stem Cells 2022;15(3):283-290
Background and Objectives:
Difficulties often encountered in separating and purifying active muscle satellite cells (MSCs) from skeletal muscle tissues have limited the supply of cells for muscle therapy and artificial meat production. Here, we report an effective isolation protocol to economically and conveniently retrieve active MSCs from skeletal muscle tissues in mice.
Methods:
and Results: We optimized an enzyme-based tissue digestion protocol for isolating skeletal muscle-derived primary cell population having a large number of active MSCs and described a method of differential plating (DP) for improving purity of active MSCs from skeletal muscle-derived primary cell population. Then, the age of the mouse appropriate to the isolation of a large number of active MSCs was elucidated. The best isolation yield of active MSCs from mouse skeletal muscle tissues was induced by the application of DP method to the primary cell population harvested from skeletal muscle tissues of 2-week-old mice digested in 0.2% (w/v) collagenase type II for 30 min at 37℃ and then in 0.1% (w/v) pronase for 5 min at 37℃.
Conclusions
The protocol we developed not only facilitates the isolation of MSCs but also maximizes the retrieval of active MSCs. Our expectation is that this protocol will contribute to the development of original technologies essential for muscle therapy and artificial meat industrialization in the future.
10.Immunologic analysis of patients with postinfectious bronchiolitis obliterans
Yun Jung CHOI ; Soyoung LEE ; Hang-Rae KIM ; Dong In SUH
Allergy, Asthma & Respiratory Disease 2022;10(2):97-104
Purpose:
This study aimed to analyze the immunologic profile of children with postinfectious bronchiolitis obliterans (PIBO) in order to approach pathophysiology affected by host factors.
Methods:
A total of 10 children with PIBO were prospectively enrolled. We obtained information on demographics from their caregiver and electric medical records. Peripheral blood samples were collected before cyclic systemic methylprednisolone therapy and complete blood count, immunoglobulin level and lymphocyte subset were analyzed.
Results:
The white blood cell count and immunoglobulin level were within the normal range in children with PIBO. The CD4+/CD8+ ratio was not significantly different from those of the healthy control group. A decreased proportion of both central memory T cells (median [interquartile range]; 13.5% [8.3%–16.3%] vs. 18.5% [15.9%–24.1%], P = 0.01) and effector memory T cells (10.3% [5.0%–18.4%] vs. 20.9% [16.6%–26.3%], P = 0.03) in CD4+T cells was observed in the PIBO group compared with those in the control group. In CD8+T cells, the proportion of effector memory T cells (7.8% [4.2%–13.8%] vs. 24.3% [15.3%–27.9%], P = 0.02) and CD45RA+effector memory T cells (16.2% [11.0%–36.6%] vs. 24.2% [17.1%–39.7%], P = 0.04) was decreased in the patient group compared with the control group.
Conclusion
It is suggested that T lymphocyte subset abnormalities may be associated with a decrease in the ability to differentiate the T cells immediately upon reinfection and induce an effective response to infection. These results may partially explain the pathophysiological individual vulnerabilities to PIBO after lower respiratory tract infections in children.

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