• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.9 no.2
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• pp.139-146
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• 2006

Purpose: Human astrovirus (HAstV) is known to be an important etiologic agent of acute gastroenteritis in infants worldwide. However, the prevalence of HAstV infection varies according to geographic region and patient age. The purpose of our study was to investigate the incidence of HAstV infection among hospitalized children at a tertiary hospital in Seoul. Methods: Fecal samples were collected from hospitalized children up to five years of age with acute gastroenteritis. A total of 812 fecal samples were collected from hospitalized children with acute gastroenteritis between February 2004 and January 2005. Fecal specimens were screened for rotavirus, enteric adenovirus and norovirus by enzyme immunoassay (EIA) or reverse transcriptase polymerase chain reaction (RT-PCR). HAstV positive samples were characterized by RT-PCR. Results: Rotavirus was detected in 16.9% (138/812), norovirus in 11.6% (94/812), and adenovirus in 4.0% (33/812) of the study population. HAstV was detected in 4.0% (33/812) samples by RT-PCR. The age distribution of HAstV positive patients was as follows: <12 month old, 82.0% (27/33); 1~2 years old, 6.0% (2/33); 2~5 years old, 12.0% (4/33). The seasonal distribution of HAstV positive samples was as follows; April (3), May (5), June (4), August (12), September (4), October (2), November (2), and December (1). The peak rate of HAstV infection was observed during the summer season, 2004. A mixed infection of viral agents was confirmed in 2.7% (22 /812) of the study population, most commonly with rotavirus and norovirus, and with rotavirus and HAstV. Genotype 1 was the predominant type (91%, 20/22) and genotype 8 was detected in two cases. Conclusion: The prevalence of HAstV infection was 4.0% in hospitalized children with acute gastroenteritis, and was especially high in infants. HAstV can be considered as an important etiologic agent of gastroenteritis in children.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.277-285
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• 2006

The most biofilm forming bacteria in catheter, Esctherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were isolated and identified from a patient's catheter occuring catheter-associated urinary tract infection (CA-UTI). We examined mRNA expression and its quantification of AIs synthetic genes encoding signal substance of quorum sensing from each bacterial species in order to elucidated quorum sensing mechanism. Both pure cultures for each bacterial strains and a mixed cultures with three were grown for 24 hr and 30 days. Initial densities to be able to detect mRNA expression oil single strains culture were shown at $2.4{\times}10^5$ CFU/ml, $5.4{\times}10^6$ CFU/ml of E. coli for ygaG and S. aureus for luxS, and at $6.9{\times}10^4$ CFU/ml of P. aeruginosa for rhlI and lasI. Also, in mixed culture of three, initial cell densities of mRNA expression were appear to at $7.3{\times}10^5$ CFU/ml, $1.6{\times}10^7$ CFU/ml of E. coli for ygaG and S. aureus for luxS, and at $2.1{\times}10^5$ CFU/ml of P. aeruginosa for rhlI and lasI. Each AIs synthetic gene was expressed in initial cell density and the mRNA expression of the genes were detected continously during 30 days. And then, the quantification of mRNA expression level of ygaG, rhlI, last, and luxS which were related AIs synthesis was done each time point by real-time RT-PCR. Interestingly, the mRNA levels of ygaG, rhlI, lasI, and luxS from the mixed culture was higher than those from each single strain culture. In the case of E. coli ygaG, the amount of transcript from the mixed culture was at least 30 times for that from single culture. In the case of P. aeruginosa rhlI and lasI, the amount of transcript from the mixed culture was at least 40 times and 250 times for that from single strain culture. In the case of S. aureus luxS, the amount of transcript from the mixed culture was at least 5 times for that from single strain culture. And specially, the mRNA expression of rhlI and lasI of P. aeruginosa showed the highest efficency among four AIs synthetic genes.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Journal of Chest Surgery
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• v.40 no.4 s.273
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• pp.264-272
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• 2007

Background: Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis, including stimulating the proliferation and migration of vascular smooth muscle cells (VSMCs). It has been known that diabetes is associated with accelerated cellular proliferation via VEGF, as compared to that under a normal glucose concentration. We investigated the effects of selective blockade of a VEGF receptor by using anti-Flt-1 peptide on the formation and hyperplasia of the neointima in balloon injured-carotid arteries of OLETF rats and also on the in vitro VSMCS' migration under high glucose conditions. Material and Method: The balloon-injury method was employed to induce neointima formation by VEGF. For f4 days beginning 2 days before the ballon injury, placebo or vascular endothelial growth factor receptor-1 (VEGFR-1) specific peptide (anti-Flt-1 peptide), was injected at a dose of 0.5mg/kg daily into the OLETF rats. At 14 days after balloon injury, the neointimal proliferation and vascular luminal stenosis were measured, and cellular proliferation was assessed by counting the proliferative cell nuclear antigen (PCNA) stained cells. To analyze the effect of VEGF and anti-Flt-1 peptide on the migration of VSMCs under a high glucose condition, transwell assay with a matrigel filter was performed. And finally, to determine the underlying mechanism of the effect of anti-Flt-1 peptide on the VEGF-induced VSMC migration in vitro, the expression of matrix metalloproteinase (MMP) was observed by performing reverse transcription-polymerase chain reaction (RT-PCR). Result: Both the neointimal area and luminal stenosis associated with neointimal proliferation were significantly decreased in the anti-Flt-1 peptide injected rats, ($0.15{\pm}0.04 mm^2$ and $ 36.03{\pm}3.78%$ compared to $0.24{\pm}0.03mm^2\;and\;61.85{\pm}5.11%$, respectively, in the placebo-injected rats (p<0.01, respectively). The ratio of PCNA(+) cells to the entire neointimal cells was also significantly decreased from $52.82{\pm}4.20%\;to\;38.11{\pm}6.89%$, by the injected anti-Flt-1 peptide (p<0.05). On the VSMC migration assay, anti-Flt-1 peptide significantly reduced the VEGF-induced VMSC migration by about 40% (p<0.01). Consistent with the effect of anti-Flt-1 peptide on VSMC migration, it also obviously attenuated the induction of the MMP-3 and MMP-9 mRNA expressions via VEGF in the VSMCS. Conclusion: Anti-Flt-1 peptide inhibits the formation and hyperplasia of the neointima in a balloon-injured carotid artery model of OLETF rats. Anti-Flt-1 peptide also inhibits the VSMCs' migration and the expressions of MMP-3 and MMP-9 mRNA induced by VEGF under a high glucose condition. Therefore, these results suggest that specific blockade of VEGFR-1 by anti-Flt-1 peptide may have therapeutic potential against the arterial stenosis of diabetes mellitus patients or that occurring under a high glucose condition.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.556-564
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• 2007

Purpose : We hypothesized that the persisting bronchial hyperresponsiveness (BHR) of adolescents with asthma remission may be controlled mainly by genetic factors, and the BHR of symptomatic asthma by airway inflammation. ${\beta}_2$-adrenoceptor gene is considered to be a candidate gene in the development of BHR. Thus, ${\beta}_2$-adrenoceptor gene polymorphism may be associated with the BHR of adolescents with asthma remission, but not with the BHR of symptomatic asthma. To evaluate this hypothesis, ${\beta}_2$-adrenoceptor gene polymorphism at 2 sites (Arg16-Gly, Gln27-Glu) were examined. Methods : Two hundred two adolescents with BHR ($PC_{20}<18\;mg/mL$) and long term remission (neither asthma-related symptoms nor medication during the previous 2 years) of their asthma (remission group), 182 adolescents with symptomatic asthma (symptomatic group), and 200 healthy adolescents (control group) were studied. Asthma phenotypes were determined using methacholine bronchial provocation test and skin prick test. Genotypes of ${\beta}_2$-adrenoceptor polymorphism were evaluated by PCR-based methods. Results : Gly/Gly allele and Gly16-Gln27 haplotype were more prevalent in the remission group than in the control group (P=0.01, P=0.02), although there was no difference between the symptomatic group and the control group. In the remission group, there was significant difference in geometric mean of $PC_{20}$ among the 3 groups subdivided by the number of Gly16-Gln27 haplotype, showing that the Gly16-Gln27 haplotype was positively associated with BHR. However, no association was found between Gly16-Gln27 haplotype and BHR in the symptomatic group. Conclusion : This study demonstrates that ${\beta}_2$-adrenoceptor polymorphism at amino acid 16 and 27 was associated with BHR persisting in adolescents with asthma remission.

• Tuberculosis and Respiratory Diseases
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• v.73 no.5
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• pp.266-272
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• 2012

Background: Limited data on the incidence and clinical characteristics of adult pertussis infections are available in Korea. Methods: Thirty-one hospitals and the Korean Centers for Disease Control and Prevention collaborated to investigate the incidence and clinical characteristics of pertussis infections among adults with a bothersome cough in non-outbreak, ordinary outpatient settings. Nasopharyngeal aspirates or nasopharyngeal swabs were collected for polymerase chain reaction (PCR) and culture tests. Results: The study enrolled 934 patients between September 2009 and April 2011. Five patients were diagnosed as confirmed cases, satisfying both clinical and laboratory criteria (five positive PCR and one concurrent positive culture). Among 607 patients with cough duration of at least 2 weeks, 504 satisfied the clinical criteria of the US Centers for Disease Control and Prevention (i.e., probable case). The clinical pertussis cases (i.e., both probable and confirmed cases) had a wide age distribution ($45.7{\pm}15.5$ years) and cough duration (median, 30 days; interquartile range, 18.0~50.0 days). In addition, sputum, rhinorrhea, and myalgia were less common and dyspnea was more common in the clinical cases, compared to the others (p=0.037, p=0.006, p=0.005, and p=0.030, respectively). Conclusion: The positive rate of pertussis infection may be low in non-outbreak, ordinary clinical settings if a PCR-based method is used. However, further prospective, well-designed, multicenter studies are needed.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.75-82
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• 2007

Purpose : Human metapneumovirus (hMPV) is a newly identified paramyxovirus that causes a variety of clinical syndromes in children, including upper and lower respiratory tract illnesses. hMPV is considered an ubiquitous virus causing respiratory tract diseases among children especially during late winter and spring seasons. We report clinical features of human metapneumovirus infection in Korean children. Methods : hMPV infection was diagnosed by reverse transcriptase-polymerase chain reaction (RT-PCR) in respiratory specimens obtained from patients with acute respiratory tract infections from October, 2004 to May, 2005. Medical records of all hMPV-positive patients were reviewed, retrospectively. Results : A total of 15 hMPV were identified from 443 nasopharyngeal aspirations by RT-PCR (3.4%). The range of age of the patients with hMPV infection was from 1 month to 62 months (median age, 31.5 months), with similar numbers of females (8/15) and males (7/15). Among hMPV-positive children, 53.3% (8/15) were aged less than 24 months. Fever, cough, rhinorrhea, vomiting, diarrhea, tachypnea, and chest wall retractions were common findings. Most common clinical diagnosis was pneumonia (60%). Two of the 15 hMPV-positive patients were also positive for adenovirus. Fever persisted from 0 to 10 days (mean 4.9 days). The duration of hospitalization ranged from 4 to 7 days (mean 5.6 days). Conclusion : hMPV accounted for a small but significant proportion of respiratory tract infection in infants and children. Future development and application of diagnostic tools will determine the burden of disease caused by this newly discovered pathogen.

• Development and Reproduction
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• v.10 no.1
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• pp.55-61
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• 2006

There is growing concern that dietary soy intake is associated with protection of breast cancer. However, questions persist on the potential adverse effects of the main soy constituent genistein(GS) on female reproductive physiology. In this study, we examined whether prepubertal exposure to GS affected on the onset of puberty and the associated reproductive parameters such as hormone receptor expressions in female rats. GS(100mg/kg/day) was administrated daily from postnatal day 25(PND 25) to the day when the first vaginal opening(VO) was observed, and the animals were sacrificed on the day after VO occurred. Gross anatomy and tissue weight were compared to test the GS's effect on the cell proliferation. Furthermore, histological studies were performed to assess the structural alterations in tissues. Specific radioimmunoassay(RIA) were carried out to measure serum LH levels. To determine the transcriptional changes in progesterone receptors(PR), total RNAs were extracted from ovary and uterus and were applied to semi-quantitative reverse transcription polymerase chain reaction(RT-PCR). As a results, advanced VO was shown in the GS group(PND $31.2{\pm}0.6$) compared to the vehicle group (PND $35.3{\pm}0.7$). GS treatment significantly increased wet weight of ovaries and uteri compared to the vehicle group. Increased serum LH levels were also shown in the GS group. Graafian follicles and corpora lutea(CL) were observed only in the ovaries from GS treated animals. Similarly, hypertrophy of luminal and glandular uterine epithelium were found only in the GS group. Collectively, these effects were probably due to the estrogenic effects of GS. In the semi-quantitative RT-PCR studies, the transcriptional activities of PR in both ovary and uterus from GS-treated group were significantly higher than those from the vehicle group. The present studies demonstrated that acute exposure to GS, at levels comparable to the ranges of human exposure, during the critical period of prepubertal stage activates the reproductive system resulting precocious puberty in immature female rats.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.46-53
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• 2016

Purpose: Enterovirus (EV) infection in children can manifest various diseases from asymptomatic infection to nonspecific febrile illness, hand-foot-mouth disease, and aseptic meningitis. This study was aimed to investigate epidemiology and clinical significance of various genotypes of EV infections in pediatric inpatient. Methods: We collected the stool samples from the admitted pediatric patients in Inha University Hospital from March 2014 to March 2015. EV detection and genotype identification were performed by real-time RT-PCR and semi-nested RT-PCR. Phylogenetic trees were constructed by neighbor joining method. Results: A total of 400 samples were collected during study period and 112 patients (28%) were diagnosed with EV infections. The mean age of EV positive patients was 2.66 years (0.1-14) and sex ratio was 1.73:1. Genetic sequences of EVs were identified; coxsackievirus B5 (17, 15.2%), coxsackievirus A16 (13, 11.6%), enterovirus 71 (10, 8.9%), and coxsackievirus A2 (9, 8.0%). Nonspecific febrile illness (96, 86%) was the most common clinical manifestation and the duration of fever was 0-11 days (mean 3.1 days). Rash (44, 39%) and meningitis (43, 38%) were followed. Patients who were attending daycare center or had siblings accounted for 82.1%. Phylogenetic relationship tree revealed 6 distinct genogroups among 56 types of EVs. Conclusions: This study is the report of epidemiology, serotype distribution and clinical manifestations of children with EV infection in Incheon. This data will be helpful for further study about the epidemiology of EV infection in Korea.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.571-576
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• 2016

In this study, the anti-inflammatory activities of the 80% ethanol extract of Dystaenia takeshimana (DT) were investigated using Raw 264.7 cells treated with lipopolysaccharide (LPS). The effect of DT extract on the production of pro-inflammatory factors (iNOS, COX-2) in LPS-stimulated Raw 264.7 macrophages was examined. The cytotoxic effect of DT extract on macrophage cells (Raw 264.7) was examined by the 3-[4, 5-dimethyl-thiazol-2-yl]-2, 5-diphenyl-tetrazoliumbromide (MTT) assay. Treatment with DT extract showed 100% or more cell viability at the concentration $1,000{\mu}g/ml$. The inhibitory effect of DT extract on protein expression of inducible NOS (iNOS) and cyclooxygenase-2 (COX-2) was measured by western blotting using the concentrations 50, 100, and $500{\mu}g/ml$, with ${\beta}-actin$ used as the positive control. Consequently, the protein expression of iNOS, and COX-2 as observed by western blotting, was decreased by 56%, 61.6%, respectively with $500{\mu}g/ml$ DT extract. Inhibition of iNOS and COX-2 mRNA expression was measured by reverse transcription- polymerase chain reaction (PCR) using DT extract concentrations 50, 100, and $500{\mu}g/ml$, with GAPDH used as a positive control. Consequently, the mRNA expression of iNOS and COX-2 as observed by reverse-transcription-PCR was decreased by 77.9% and 83.3%, respectively at $500{\mu}g/ml$ concentration of DT extract. In conclusion, DT extract may affect inflammatory factors as a potential anti-inflammatory agent.