• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.138-145
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• 2008

Purpose : Acute gastroenteritis is a frequent childhood disease. The purpose of this study is to determine if certain pathogens are related to more severe clinical disease in children with acute gastroenteritis. Methods : Two hundred seventy one stool samples were obtained from pediatric patients with acute gastroenteritis that was associated with virus, bacteria and protozoa infection between January 2006 and December 2006. The clinical severity was assessed by using the 24 point scale Clark score. We evaluate the Clark score according to the pathogens. Results : One hundred thirty seven children were noted to have virus, bacteria or protozoal infection. Rotavirus was the most common pathogen found in the children with gastroenteritis (20.6%). Other frequent pathogens were norovirus (10.7%) and E. coli (12.9%). Vomiting (P=0.049) and diarrhea (P=0.003) symptoms were more frequent in the rotavirus group than that in the rotavirus negative group. There were no statistical differences in the Clark score between the virus positive group and the virus negative group. Conclusion : We concluded that rotavirus was the most common pathogen in children with gastroenteritis, yet the clinical severity was not dependent on the presence of viral or bacterial pathogens.

• Research in Plant Disease
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• v.10 no.1
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• pp.34-38
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• 2004

The damage of plant growth and alteration of cellular tissues of barley infected by Barley yellow mosaic virus (BaYMV) was explored. The infected plots significantly damaged in all of measured factors by the disease. In severely diseased plant, the viral infection affected on plant growth like as shorten culm length about 25cm, 36％ constrained ratio, comparing to healthy. The yield decreased over 70％ in diseased plots by fewer numbers of spike and kernel per square meter and spike, respectively. BaYMV constructed typical inclusion body like a pinwheel type inside barley leaves, and the infection affected on cellular elongation or growth not cell division in examined three parts as stem, neck of panicle and node, related to dwarfness of infected barley. The stem tissues were most severely affected on cell growth as restrained epidermis cell length in diameter and vascular bundle size. In neck of panicle tissues, distribution and size of tissues of fiber and cortex parts, respectively, showed differences between healthy and infected plants. In node part, healthy plant showed bigger tissue size as 1.5 times than infected plant. Theses results suggest that BaYMV infection could affect on the cell growth not cell division, and which resulted shorten culm length in plant growth and decreased yield, finally.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1583-1590
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• 2006

T4 endonuclease V (T4 endo V) [EC 3. 1. 25. 1], found in bacteriophage T4, is responsible for excision repair of damaged DNA. The enzyme possesses two activities: a cyclobutane pyrimidine dimer DNA glycosylase (CPD glycosylase) and an apyrimidic/apurinic endonuclease (AP lyase). T4 denV (414 bp cDNA) encoding T4 en do V (138 amino acid) was synthesized and expressed using either an expression vector, pTriEx-4, in E. coli or a baculovirus AcNPV vector, pBacPAK8, in insect cells. The recombinant His-Tag/T4 endo V (rHis-Tag/T4 endo V) protein expressed from bacteria was purified using one-step affinity chromatography with a HiTrap Chelating HP column and used to make rabbit anti-His-Tag/T4 endo V polyclonal antibody for detection of recombinant T4 endo V (rT4 endo V) expressed in insect cells. In the meantime, the recombinant baculovirus was obtained by cotransfection of BacPAK6 viral DNA and pBP/T4 endo V in Spodoptera frugiperda (Sf21) insect cells, and used to infect Sf21 cells to overexpress T4 endo V protein. The level of rT4 endo V protein expressed in Sf21 cells was optimized by varying the virus titers and time course of infection. The optimal expression condition was set as follows; infection of the cells at a MOI of 10 and harvest at 96 h post-infection. Under these conditions, we estimated the amount of rT4 endo V produced in the baculovirus expression vector system to be 125 mg/l. The rT4 endo V was purified to homogeneity by a rapid procedure, consisting of ion-exchange, affinity, and reversed phase chromatographies, based on FPLC. The rT4 endo V positively reacted to an antiserum made against rHis-Tag/T4 endo V and showed a residual nicking activity against CPD-containing DNA caused by UV. This is the first report to have T4 endo V expressed in an insect system to exclude the toxic effect of a bacterial expression system, retaining enzymatic activity.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.342-347
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• 2011

T cells play a key role in viral infection. However, in patients with chronic hepatitis C virus (HCV) infection, HCV-specific T cells are dysfunctional and impaired in the liver, which is the primary site for HCV replication. There are multiple potential mechanisms for HCV-specific T cell dysfunction including induction of immune inhibitory pathways (program death-1; PD-1, cytotoxic t lymphocyte associated antigen-4; CTLA-4) and immune tolerance induced specific for the liver. However, the interaction between hepatocytes and HCV-specific CD8 T cells has not clearly established. In this study, we confirmed huh (human hepatoma) 7.5 cells expressing HLA (human leukocyte antigen) A2 presented antigen to activate HCV-specific CD8 T cells in HLA A2-restricted manner and expression of PD-L (program death ligand) 1 on huh7.5 cells reduced HCV-specific CD8 T cell activation, suggesting an immune modulatory activity. Loss of HCV-specific tetramer responses following antigenic stimulation correlated with increased caspase-3 activity. In addition, PD-L1 on huh7.5 cells rescued HCV-specific CD8 T cells from apoptosis. Our results suggest that the interaction between PD-L1 and PD-1 can recover the function of HCV-specific CD8 T cells in the liver, which could be applied in therapy of HCV chronic infection.

• Neonatal Medicine
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• v.15 no.1
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• pp.61-66
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• 2008

Purpose : The purpose of this study was to describe the epidemiologic features of febrile illnesses in newborns and to predict the risk of serious infections in this population. Methods : A retrospective study was conducted on 123 full-term infants <30 days of age with an axillary temperature >38$^{\circ}C$ who were hospitalized between 2000 and 2006. Neonates with prenatal risk factors, congenital anomalies, antibiotic administration prior to admission to the hospital, or suspected hospital-acquired infections were excluded. We evaluated the symptoms, physical examination findings, laboratory data, and clinical course between the high- and low-risk groups for serious infections. Results : The high-risk group included 30 infants with the following diagnoses in order of frequency: aseptic meningitis, urinary tract infection, bacterial meningitis, infectious enteritis, sepsis concomitant with disseminated intravascular coagulopathy, bacteremia, pneumonia, cellulitis, and omphalitis. Leukocytosis and thrombocytopenia were statistically different between the two groups. Factors, such as moaning signs, seizures, body temperature, and pulse rate were statistically significant. Conclusion : Unlike previous studies, we included newborns with clinical bacterial infections and aseptic meningitis as the high-risk group. Leukocytosis, thrombocytopenia, moaning signs, seizures, and changes in vital signs were considered useful predictors for identifying febrile neonates at high-risk for serious infections in spite of a difference in the definition of serious infection.

• Journal of Industrial Convergence
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• v.21 no.1
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• pp.175-185
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• 2023

Recently, novel viral infections such as COVID-19 have spread and pose a serious public health problem. In particular, these diseases have a fatal effect on the elderly, threatening life and causing serious social and economic losses. Accordingly, applications such as telemedicine, healthcare, and disease prevention using the Internet of Things (IoT) and artificial intelligence (AI) have been introduced in many industries to improve disease detection, monitoring, and quarantine performance. However, since existing technologies are not applied quickly and comprehensively to the sudden emergence of infectious diseases, they have not been able to prevent large-scale infection and the nationwide spread of infectious diseases in society. Therefore, in this paper, we try to predict the spread of infection by collecting various infection information with regional limitations through a virus disease information collector and performing AI analysis and severity matching through an AI broker. Finally, through the Korea Centers for Disease Control and Prevention, danger alerts are issued to the elderly, messages are sent to block the spread, and information on evacuation from infected areas is quickly provided. A realistic elderly support system compares the location information of the elderly with the information of the infected area and provides an intuitive danger area (infected area) avoidance function with an augmented reality-based smartphone application. When the elderly visit an infected area is confirmed, quarantine management services are provided automatically. In the future, the proposed system can be used as a method of preventing a crushing accident due to sudden crowd concentration in advance by identifying the location-based user density.

• Pediatric Infection and Vaccine
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• v.19 no.3
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• pp.121-130
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• 2012

Purpose : The purpose of this study is to investigate clinical features and causative organisms in febrile infants younger than three months, to help identification of high risk patients for serious bacterial infection (SBI). Methods : A total of 313 febrile infants younger than three months, who had visited Seoul National University Children's Hospital from January 2008 to December 2010 were included. Clinical features, laboratory findings, causative organisms, and risk factors of SBI were analyzed by retrospective chart review. Causative bacterial or viral pathogens were identified by gram stain and cultures, rapid antigen tests, or the polymerase chain reaction from clinically reliable sources. Results : Among 313 infants, etiologic organisms were identified in 127 cases (40.6%). Among 39 cases of bacterial infections, Escherichia coli (66.7%) and Streptococcus agalactiae (12.8%) were common. Enterovirus (33.7%), respiratory syncytial virus (19.8%), and rhinovirus (18.8%) were frequently detected in 88 cases of viral infection. Patients with SBI (39 cases) showed significantly higher values of the white blood cell count ($14,473{\pm}6,824/mm^3$ vs. $11,254{\pm}5,775/mm^3$, P=0.002) and the C-reactive protein ($6.32{\pm}8.51mg/L$ vs. $1.28{\pm}2.35mg/L$, P<0.001) than those without SBI (274 cases). The clinical risk factors for SBI were the male (OR 3.7, 95% CI 1.5-8.9), the presence of neurologic symptoms (OR 4.8, 95% CI 1.4-16.8), and the absence of family members with respiratory symptoms (OR 3.6, 95% CI 1.2-11.3). Conclusion : This study identified common pathogens and risk factors for SBI in febrile infants younger than three months. These findings may be useful to guide management of febrile young infants.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.101-109
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• 2021

Purpose: Common human coronaviruses (HCoVs) are relatively understudied due to the mild nature of HCoV infection. Given the lack of local epidemiology data on common HCoVs, we aimed to describe clinical and epidemiological characteristics of common HCoVs in children. Methods: Respiratory viral test results from 9,589 respiratory samples from Seoul National University Children's Hospital were analyzed from January 2015 to December 2019. Viral detection was done by the multiplex reverse transcription polymerase chain reaction. Demographics and clinical diagnosis were collected for previously healthy children tested positive for HCoVs. Results: Of the 9,589 samples tested, 1 or more respiratory viruses were detected from 5,017 (52.3%) samples and 463 (4.8%) samples were positive for HCoVs (OC43 2.8%, NL63 1.4%, 229E 0.7%). All 3 types co-circulated during winter months (November to February) with some variation by type. HCoV-OC43 was the most prevalent every winter season. HCoV-NL63 showed alternate peaks in late winter (January to March) and early winter (November to February). HCoV-229E had smaller peaks every other winter. Forty-one percent of HCoV-positive samples were co-detected with additional viruses; human rhinovirus 13.2%, respiratory syncytial virus 13.0%, influenza virus 4.3%. Common clinical diagnosis was upper respiratory tract infection (60.0%) followed by pneumonia (14.8%), croup (8.1%), and bronchiolitis (6.7%). Croup accounted for 17.0% of HCoV-NL63-positive children. Conclusions: This study described clinical and epidemiological characteristics of common HCoVs (OC43, NL63, 229E) in children. Continuing surveillance, perhaps by adding HKU1 in the diagnostic panel can further elucidate the spectrum of common HCoV infections in children.

• Clinical and Experimental Pediatrics
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• v.52 no.11
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• pp.1241-1248
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• 2009

Purpose:The etiology of Kawasaki disease (KD) is still unknown. Recently, an association between human coronavirus NL63 (HCoV-NL63) and KD was implicated. Hence, we attempted to determine the association between KD and acute respiratory viral infections. Methods:Nasopharyngeal aspirate samples were obtained from 54 patients diagnosed with KD at the Seoul National University (SNU) Children's Hospital and SNU-Bundang Hospital between October 2003 and September 2006. Viral diagnoses of 11 respiratory viruses were made using multiplex reverse transcriptase-polymerase chain reaction (RT-PCR): respiratory syncytial virus (RSV), adenovirus, rhinovirus (RV), parainfluenza viruses (PIVs) 1 and 3, influenza viruses (IFVs) A and B, human metapneumovirus (HMPV), human bocavirus (HBoV), HCoV OC43/229E, and HCoV-NL63. Clinical data were reviewed retrospectively. Results:The median age was 32 months (6 months-10.4 years). Respiratory symptoms were observed in 37 patients (69%). The following respiratory viruses were identified in 12 patients (22%): RV (n=4), PIV-3 (n=2), HBoV (n=2), and adenovirus, RSV, PIV-1, IFV-A, and HCoV-NL63 (n=1). Co-infection with PIV-3 and RV was observed in one patient. Respiratory symptoms were observed in 7 (58.3%) and 30 (71.4%) patients of the virus-positive and virus-negative groups (P>0.05). Response rate to intravenous immunoglobulin administration was 67% (n=8) and 86% (n=36) in the virus- positive and virus-negative groups (P>0.05). Conclusion:Respiratory symptoms were commonly observed in KD patients but the association between respiratory viruses and KD were not found. Large multicenter-based investigations are required to confirm the association between acute respiratory viral infections and KD.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.477-482
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• 2006

Viral diseases, especially Barley yellow mosaic virus (BaYMV) and Barley mud mosaic virus (BaMMV), have been most serious in barley fields. In this study, we investigated the effect of different level of resistance to viral diseases on the plant growth and yield in barley. Various viral disease symptoms on leaves of overwintered plants were similar between medial-resistant and susceptible varieties of Saessalbori and Baegdong. In diagnosis of virus infection, BaYMV and BaMMV were detected in Saessalbori and Baegdong, but not in the resistant variety, Naehanssalbori. Plant height was restrained about $11{\sim}12cm$ prior to heading in Saessalbori and Baegdong comparing to Naehanssalbori. Even if both varieties were medial resistant to virus diseases, Saessalbori was different from Baegdong in heading date and culm length due to its recovery from viral damages prior to heading. Both medial-resistant and susceptible varieties were quite different from the resistant variety in yield components such as heading date, number of spikes and culm length when evaluated in the virus-infected or non-infected field. Baegdong delayed 7 days in heading date and reduced by more than 50% in culm length and spike numbers as compared to Naehanssalbori. On the other hand, Saessalbori showed similar heading date, but was shorter by 20% in culm length than Naehanssalbori. Three varieties tested in the non-infected field over two years were not significantly different for yield potential with ranges of $340{\sim}405kg/10a$. However, significant yield reduction (P<0.01) was observed in Saessalbori and Baegdong with ranges of $108{\sim}288kg/10a$ as compared to Naehanssalbori (391 kg/10a) when tested in the virus-infected field. Yield potentials of Saessalbori and Baegdong reduced by 35 and 63%, respectively in the virus-infected field as compared to those in the non-infected field. Our results showed that damages from virus diseases were significant on the early plant growth to yield and its components in barley.