• Journal of Life Science
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• v.33 no.1
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• pp.64-72
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• 2023

Despite several advances in identification of cardiac transcription factors, there are still needs to find new bioactive molecules that promote cardiomyogenesis from stem cells to highly efficient myocardial differentiation. We analyzed Illumina expression microarray data of mouse embryonic stem cells (mESCs)-derived cardiomyocytes. 276 genes were upregulated (≥ 4fold) in mESCs-derived cardiomyocytes compared undifferentiated ESCs. Secreted phosphoprotein 2 (Spp2) is one of candidates and is known to inhibit bone morphogenetic protein 2 (BMP2) signal transduction as a pseudoreceptor for BMP2. However, its function in cardiomyogenesis is unknown. We confirmed that Spp2 expression increased during the differentiation into functional cardiomyocytes using mESCs, TC-1/Kh2 and E14. Interestingly, Spp2 secretion transiently increased 3 days after formation of embryoid bodies (EBs), indicating that the extracellular secretion of Spp2 is involved in the differentiation of ESCs into cardiomyocytes. To characterize Spp2, we performed experiments using the C2C12 mouse myoblast cell line, which has the property of shifting the differentiation pathway from myoblastic to osteoblastic by treatment with BMP2. Similar to the differentiation of ESCs, transcription of Spp2 increased as C2C12 myoblasts differentiated into myotubes. In particular, Spp2 secretion increased dramatically in the early stage of differentiation. Furthermore, treatment with Spp2-Flag recombinant protein promoted the differentiation of C2C12 myoblasts into myotubes. Taken together, we suggest a novel bioactive protein Spp2 that differentiates ESCs into cardiomyocytes. This may be useful for understanding the molecular pathways of cardiomyogenesis and for experimental or clinical promotion of stem cell therapy for ischemic heart diseases.

• Journal of Life Science
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• v.33 no.8
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• pp.605-611
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• 2023

Recently, sporadic cases of human infection by genetic reassortants of H7Nx influenza A viruses have been reported; such viruses have also been continuously isolated from avian species. In this study, A/wild bird/South Korea/sw-anu/2023, a novel reassortant of the H7N1 avian influenza virus, was analyzed using full-genome sequencing and molecular characterization. Phylogenetic analysis showed that A/wild bird/South Korea/sw-anu/2023 belonged to the Eurasian lineage of H7Nx viruses. The polymerase basic (PB)2, PB1, polymerase acidic (PA), and nucleoprotein (NP) genes of these viruses were found to be closely related to those of avian influenza viruses isolated from wild birds, while the hemagglutinin (HA), neuraminidase (NA), matrix (M), and nonstructural (NS) genes were similar to those of avian influenza viruses isolated from domestic ducks. In addition, A/wild bird/South Korea/sw-anu/2023 also had a high binding preference for avian-specific glycans in the solid-phase direct binding assay. These results suggest the presence of a new generation of H7N1 avian influenza viruses in wild birds and highlight the reassortment of avian influenza viruses found along the East Asian-Australasian flyway. Overall, H7Nx viruses circulate worldwide, and mutated H7N1 avian viruses may infect humans, which emphasizes the requirement for continued surveillance of the H7N1 avian influenza virus in wild birds and poultry.

• Pediatric Infection and Vaccine
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• v.30 no.2
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• pp.97-103
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• 2023

Kawasaki disease (KD) is an acute, systemic inflammatory disorder that often targets coronary arteries. Being the common cause of acquired heart disease in children, timely diagnosis and intravenous immunoglobulin treatment are crucial. However, it is challenging for physicians to diagnose KD if it presents with atypical manifestations. We report the case of a 5-year-old boy who initially presented with appendicitis; after an appendectomy, he had a prolonged fever. He was finally diagnosed with atypical KD and successfully recovered after intravenous immunoglobulin treatment. Through a literature review, we found 21 cases of appendicitis associated with KD. In most cases, the patients were male with a mean age of 5.3 years. Most had higher proportions of incomplete KD and coronary artery complications than expected for typical KD. In conclusion, appendicitis could be a rare complication of KD; therefore, multidisciplinary cooperation and early recognition of atypical KD are essential for timely diagnosis.

• Pediatric Infection and Vaccine
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• v.30 no.2
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• pp.55-61
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• 2023

Purpose: Urinary tract infections (UTIs) pose a significant disease burden in children. This study aims to determine whether a short-course regimen is non-inferior to a standard-course regimen in children with UTIs without complication and presence of bacteremia, and to define, in the optimal way possible, the term "short-course" in this context. Methods: We conducted a rapid systematic review of research up to April 2021 in PubMed, Embase, and Cochrane databases. We included studies that compared clinical outcomes in pediatric UTIs treated with short-course(≤4 days) or standard (≥5-7 days) courses. Results: Our analysis suggests that short-course regimes have equivalent efficacy to standard-course regimens, with similar clinical cure rates and recurrence rates. All 10 studies comparing the clinical cure rates of short- and standard-course regimens reported comparable outcomes. The study evaluating renal scarring indicated no inferiority of short-course regimens compared to standard-course ones. Regarding UTI relapse, 8 out of 10 studies reported no significant difference in outcomes between short- and standard-course regimens. Conclusions: Our results purpose that short-course UTI regimens of 6 days or less are just as effective as standard-term regimens of 7 days or more in terms of infection cure and prevention of recurrence. Considering the equivalent rates of clinical cure and relapse between short- and standard-course regimens, it could be inferred that short-course regimens might be a more optimal strategy for managing pediatric UTIs without increasing the risk of complications.

• Pediatric Infection and Vaccine
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• v.30 no.2
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• pp.62-72
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• 2023

Purpose: A change is expected in the pattern of respiratory viruses including human coronavirus (HCoV) after the coronavirus disease 2019 (COVID-19) outbreak. Accordingly, identifying the distribution of respiratory viruses before the COVID-19 outbreak is necessary. Methods: We retrospectively analyzed the results of samples of nasal swabs collected from children under aged ≤18 years who were hospitalized at Myongji Hospital, Gyeonggi-do due to acute respiratory infections from 2017 to 2019. Viruses were detected by real-time reverse transcription polymerase chain reaction (RT-PCR). Results: Out of 3,557 total patients, 3,686 viruses were detected with RT-PCR including coinfections. Of the 3,557 patients, 2,797 (78.6%) were confirmed as PCR-positive. Adenovirus and human rhinovirus (hRV) were detected throughout the year, and human enterovirus was most detected during summer. Respiratory syncytial virus, influenza virus, and HCoV were prevalent in winter. In patients with croup, parainfluenza virus was most frequently detected, followed by hRV and HCoV. The PCR positive rate in summer and winter differed significantly. Conclusions: Respiratory virus patterns in northwestern Gyeonggi-do were not much different from previously reported data. The data reported herein regarding respiratory virus epidemiological information before the COVID-19 outbreak can be used for use in comparative studies of respiratory virus patterns after the COVID-19 outbreak.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.12-19
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• 2023

Purpose: Sepsis is the most common cause of neonatal death accounting for 30-50% of mortality annually in developing countries. This study was to determine the prognostic factors of neonatal sepsis mortality. Methods: A retrospective cohort was conducted in Dr. R. Sosodoro Djatikoesoemo Governor Hospital from April 2021 to September 2021 on 121 neonates in the neonatal intensive care unit (NICU) diagnosed with sepsis. The inclusion criteria were neonates aged 0-28 days, admitted to the NICU, and diagnosed with sepsis. The exclusion criteria were incomplete data and the presence of congenital abnormalities. A χ² test was performed on the sex, gestational age, mode of delivery, birth weight, APGAR score, birthplace, and blood culture. A normality test was performed on leukocytes, lymphocytes, neutrophils, platelets, C-reactive protein (CRP), and length of stay. Then performed a Mann-Whitney test. Results: Birth weight (P=0.038), gestational age (P=0.009), and blood culture (P=0.014) showed a significant relationship with the neonatal sepsis outcome while Mann-Whitney test showed significant differences in the platelets (P=0.018), CRP (P=0.002), and length of stay (P<0.001). Multivariate analysis showed that 3 prognostic factors associated with neonatal sepsis mortality were prematurity (odds ratio [OR], 3.906; 95% confidence interval [CI], 1.344-11.356; P=0.012), low birth weight (LBW, OR, 2.833; 95% CI, 1.030-7.790; P=0.044), and gram-negative bacteria (OR, 4.821; 95% CI, 1.018-22.842; P=0.047). Conclusions: Prematurity, LBW, and gram-negative bacteria were associated with the prognostic factors of neonatal sepsis.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.33-38
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• 2023

A case of persistent Ralstonia mannitolilytica bacteremia in the neonatal intensive care unit prompted source investigation due to its rarity. After an extensive investigation, a contaminated ultrasonic nebulizer was identified as the source, and the infection was controlled by removing the source. This study emphasizes the importance of further investigations, even in single cases of rare pathogens.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.47-54
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• 2023

With the widespread use of broad-spectrum antibiotics in clinical practice, the emergence of multidrug-resistant (MDR) gram-negative bacteria has become a global problem. The MDR Pseudomonas aeruginosa infection is especially difficult to treat and increases mortality in critically ill patients. Ceftolozane-tazobactam (Zerbaxa^TM) is a fifth-generation cephalosporin and beta-lactamase inhibitor that has proved to be effective for treating complicated urinary tract infections and complicated intra-abdominal infections caused by MDR P. aeruginosa. Herein, we report the first case of pediatric hematologic cancer in Korea that was successfully treated for MDR P. aeruginosa bacteremia with Ceftolozane-tazobactam.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.9
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• pp.283-290
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• 2023

With the recent steady development of IoT technology, it is widely used in medical systems and smart TV watches. 66% of software development is developed through language C, which is vulnerable to memory attacks, and acts as a threat to IoT devices using language C. A stack-smashing overflow attack inserts a value larger than the user-defined buffer size, overwriting the area where the return address is stored, preventing the program from operating normally. IoT devices with low memory capacity are vulnerable to stack smashing overflow attacks. In addition, if the existing vaccine program is applied as it is, the IoT device will not operate normally. In order to defend against stack smashing overflow attacks on IoT devices, we used canaries among several detection methods to set conditions with random values, checksum, and DSLR (random storage locations), respectively. Two canaries were placed within the buffer, one in front of the return address, which is the end of the buffer, and the other was stored in a random location in-buffer. This makes it difficult for an attacker to guess the location of a canary stored in a fixed location by storing the canary in a random location because it is easy for an attacker to predict its location. After executing the detection program, after a stack smashing overflow attack occurs, if each condition is satisfied, the program is terminated. The set conditions were combined to create a number of eight cases and tested. Through this, it was found that it is more efficient to use a detection method using DSLR than a detection method using multiple conditions for IoT devices.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.83-93
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• 2024

Purpose: Since the start of the coronavirus disease 2019 (COVID-19) pandemic, various variants of concern have emerged. We divided the representative COVID-19 mutation period into four waves and aimed to analyze the clinical and laboratory features of children with COVID-19 from pre-mutation wave to the middle of omicron wave. Methods: We retrospectively reviewed the medical records of hospitalized patients aged ≤19 years with laboratory confirmed COVID-19. Clinical and laboratory findings during pre-mutation (February 1st 2020 to September 30th 2020), alpha/beta (October 1st 2020 to May 31st 2021), delta (June 1st 2021 to October 31st 2021), and omicron (November 1st 2021 to May 31st 2022) waves were compared. Results: Among total 827 patients, 163 (19.7%) were asymptomatic, and the frequency of fever and cough was 320 (38.7%) and 399 (48.2%), respectively. The proportion of fever ≥38.5℃ was observed to be high during the omicron wave in the age group under 12 years. Lymphopenia was observed highly in the omicron wave in the age group under 12 years, and in the delta wave in the age group older than 12 years. Neutropenia was highly observed in the delta wave in the 0-4 years age group. Conclusions: There were distinct characteristics during all epidemic waves of COVID-19. Children with COVID-19 had more frequent persistent fever during delta wave and children during the omicron wave had a higher peak fever.