• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.261-271
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• 2016

Citrus is an economically important fruit crop widely growing worldwide. However, citrus production largely depends on natural hybrid selection and bud sport mutation. Unique botanical features including long juvenility, polyembryony, and QTL that controls major agronomic traits can hinder the development of superior variety by conventional breeding. Diverse factors including drastic changes of citrus production environment due to global warming and changes in market trends require systematic molecular breeding program for early selection of elite candidates with target traits, sustainable production of high quality fruits, cultivar diversification, and cost-effective breeding. Since the construction of the first genetic linkage map using isozymes, citrus scientists have constructed linkage maps using various DNA-based markers and developed molecular markers related to biotic and abiotic stresses, polyembryony, fruit coloration, seedlessness, male sterility, acidless, morphology, fruit quality, seed number, yield, early fruit setting traits, and QTL mapping on genetic maps. Genes closely related to CTV resistance and flesh color have been cloned. SSR markers for identifying zygotic and nucellar individuals will contribute to cost-effective breeding. The two high quality citrus reference genomes recently released are being efficiently used for genomics-based molecular breeding such as construction of reference linkage/physical maps and comparative genome mapping. In the near future, the development of DNA molecular markers tightly linked to various agronomic traits and the cloning of useful and/or variant genes will be accelerated through comparative genome analysis using citrus core collection and genome-wide approaches such as genotyping-by-sequencing and genome wide association study.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.1
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• pp.36-43
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• 2010

Purpose: The aim of this study was to evaluate the clinical features and factors contributing to treatment outcome for chronic functional constipation in children. Methods: We analyzed the medical records of patients with constipation, who visited the inpatient or outpatient clinic of the Department of Pediatrics of Pusan National University Hospital, between January 1998 and December 2007. The clinical features, outcomes, and factors affecting the treatment response according to the main drug (lactulose vs. PEG 4000) were analyzed retrospectively. Results: Two hundred forty children (142 males and 98 females) were enrolled in this study. The mean age was 51.2${\pm}$37.9 months. The duration of symptoms was 32.6${\pm}$33.7 months. The accompanying symptoms were as follows: encopresis, 91 (30.4%); abdominal pain, 76 (31.6%); and blood-tinged stool, 37 (15.4%). The treatment response was achieved earlier in females (p<0.001), patients with accompanying symptoms (p<0.05), and patients treated with PEG 4000 (p=0.001). The duration of symptoms (p<0.05) and stool frequency before treatment (p<0.05) were related to a delayed treatment response. Relapse occurred in 7 children, all of whom were treated successfully later. Conclusion: Factors contributing to treatment response are female gender, accompanying symptoms, duration of symptoms, and stool frequency before treatment. PEG 4000 is superior to lactulose in response time and taken into consideration as a primary drug for the treatment of functional constipation of children. Early treatment and sufficient treatment time may also be important factors to achieve an early response and prevent relapse.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.1
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• pp.23-29
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• 2010

Purpose: The aim of this study was to assess the benefits of routine pre-endoscopy coagulation screening tests and platelet counts in Korean children. Methods: Between March 2004 and December 2009, children who underwent gastrointestinal endoscopy for the evaluation of various gastrointestinal symptoms were included. All of the subjects included in the study also underwent routine coagulation screening and platelet count determinations prior to endoscopy and biopsy. The clinical records and laboratory tests were retrospectively reviewed in all patients. Results: One hundred sixty-two of 1,476 (11%) patients who underwent endoscopy had abnormal results on pre-screening coagulation tests. Fourteen patients underwent coagulation factor assays due to abnormal clotting results in consecutive tests or due to clinical evidence of a bleeding tendency. Seven patients were diagnosed with factor XII deficiency, one patient was diagnosed with von Willebrand disease, one patient had von Willebrand disease and factor XII deficiency, and one patient was presumed to have mild hemophilia. The remaining 4 patients had normal results with the factor assays. The results of platelet counts were normal with the exception of 1 patient. No patient had significant bleeding during the endoscopic procedures, despite abnormal pre-endoscopic coagulation tests. Conclusion: Routine coagulation screening tests and platelet counts revealed abnormal results in some patients. Most of the patients with abnormal clotting were shown to have a factor XII deficiency, which had no significant associated bleeding tendencies; the other patients were diagnosed with hemophilia or von Willebrand disease. Therefore, although abnormal pre-endoscopic coagulation is not always related to significant bleeding complications, pre-endoscopic coagulation screening may be useful in some children in predicting the risk of bleeding tendency during endoscopic procedures.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.1
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• pp.7-22
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• 2010

Purpose: Nodular gastritis is a characteristic finding of Helicobacter pylori infection in children. The aim of this study was to evaluate the difference in gene expression in the gastric mucosa of H. pylori-infected and non-infected children, and to analyze the difference in gene expression using cDNA microarray analysis of nodular gastritis caused by H. pylori infection. Methods: Twelve children (6 boys and 6 girls; mean age 9.8 years) who underwent upper gastrointestinal endoscopy and biopsy at Seoul National University Bundang Hospital were included in the study. The subjects were divided into three groups according to the presence of H. pylori infection and nodular gastritis on endoscopic examination. Gastric mucosa tissue was kept at $-70^{\circ}C$ and RNA was extracted to perform cDNA microarray analysis in each patient. Results: cDNA microarray analysis in children revealed a clear distinction between H. pylori-infected and non-infected gastric mucosa. Specifically, 182 over-expressed genes and 29 under-expressed genes were identified in H. pylori-infected gastric mucosa compared to non-infected mucosa. H. pylori-infected nodular gastritis revealed different gene expression patterns from H. pylori-infected normal gastric mucosa; five genes were over-expressed and five genes were under-expressed. Conclusion: In the presence of H. pylori infection, gastric mucosa shows distinct differences in gene expression, and nodular gastritis with H. pylori infection in children may be associated with over- or under-expression of some genes. Further studies are required to clarify the host response and the pathogenesis of nodular gastritis in children.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.12 no.2
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• pp.163-170
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• 2009

Purpose: Intussusception is the most common cause of intestinal obstruction in young children. Although intussusceptions are easily treated, some intussusceptions with or without a pathologic lead point (PLP) often recur. In this study, we analyzed the clinical characteristics and prognosis of recurrent intussusceptions (RI), the frequency of the PLP, and correlation between RI with PLP. Methods: The medical records of 144 patients, among 590 patients with intussusceptions who had been admitted to the Department of Pediatrics and Pediatric Surgery of Dankook University Hospital between May 1994 and June 2009 were reviewed retrospectively. Results: The overall recurrence rate of intussusceptions in this study was 9.2%. The mean interval between the initial occurrence and the first recurrent attack was 130${\pm}$175 days (range, 12 hours to 3 years). There was no statistically significant difference in the recurrence rate among patients who underwent air, barium, and manual reduction (p=0.131). Eighty-seven cases (92.6%) of RI had a successful reduction by the use of non-operative techniques. A PLP was present in 18 patients (3.0%). The most common PLP was intestinal lymphoid hyperplasia, followed by Meckel's diverticulum, duplication cyst, intestinal polyp, and adenomyoma. The mean number of intussusceptions was 4.7${\pm}$1.9 in 7 patients with PLP, which was significantly higher than (2.4${\pm}$0.9) patients without a PLP (p=0.023). The mean duration of recurrences was 17.4${\pm}$19.8 months (range, 2 days to 72 months). Conclusion: A careful search for a PLP should be performed to prevent recurrence of intussusception, especially when intussusception has recurred more than three times.

• Pediatric Infection and Vaccine
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• v.27 no.1
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• pp.35-44
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• 2020

Purpose: This study aimed to investigate the clinical features of recurrent urinary tract infection (UTI) in children with vesicoureteral reflux (VUR) and to compare the causative uropathogen and antibiotic susceptibility between the first and recurrent UTI episodes. Methods: We retrospectively reviewed the medical records of children with VUR who had recurrent UTI. Group 1 included patients in whom the same pathogen caused the first and recurrent UTI episodes. Group 2 included patients in whom different pathogens caused the first and recurrent UTI episodes. Results: During a 13-year study period (2005-2018), 77 children with VUR experienced at least one episode of UTI. Among these, 47 patients (61.0%) had recurrent UTI. Of the children with recurrent UTI, 19 (40.4%) were in group 1 and 28 (59.6%) were in group 2. Escherichia coli was the most commonly isolated uropathogen (n=37; 39.4%) in both episodes of recurrent UTIs, followed by Klebsiella pneumoniae (n=18; 19.1%), Enterococcus faecalis (n=14; 14.9%), and Enterobacter aerogenes (n=7; 7.4%). Although the difference was not significant, the rate of resistance to the antibiotics ceftazidime, piperacillin/tazobactam, and trimethoprim-sulfamethoxazole increased in patients with the second episode of E. coli recurrence in group 1, and that to cefotaxime, ceftazidime, piperacillin/tazobactam, and meropenem increased in children with the second episode of E. aerogenes recurrence in group 1. Conclusions: When selecting empirical antibiotics for recurrent UTI in children with VUR, it is important to consider that the pathogen and antimicrobial susceptibility of the previous UTI are not always the same in recurrent UTIs.

• Pediatric Infection and Vaccine
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• v.8 no.1
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• pp.94-100
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• 2001

Purpose : Enterovirus is a common cause of aseptic meningitis and nonspecific febrile illness in young children. During the summer and fall months, enterovirus-infected young children are frequently admitted and evaluated to rule out bacterial sepsis and/or meningitis. The purpose of this study was to evaluate the relationship between nonpolio enterovirus infection and febrile illness in infants under 3 months of age during the summer, fall months by using a stool culture to identify the presence of enterovirus. Methods : Patients included febrile infants under 3 months of age admitted to Masan Fatima Hospital for sepsis evaluation from May 1999 to September 1999. Cultures were performed from stool and Cerebrospinal fluid samples and then were tested for enterovirus infection. Viral isolation and serotype identification were performed by cell culture and immunofluorescent testing. Enteroviruses not typed by immunofluorescent testing were confirmed by reverse transcription-polymerase chain reaction. Results : A total of 44 febrile infants were enrolled; of those, 20(45%) were positive for enterovirus. Two enterovirus culture-positive infants had concomitant urinary tract infection and one had Kawasaki disease. All infants infected with an enterovirus recovered without complications. Serotype of 20 enteroviruses were isolated from stool, 3 of echovirus type 9, 1 of echovirus type 11, 1 Coxsachievirus type B4, 15 of untyped enteroviruses. One untyped enterovirus was isolated in the CSF. Conclusion : Nonpolio enterovirus infections are associated with nonspecific febrile illnesses in infants under 3 months of age.

• Pediatric Infection and Vaccine
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• v.8 no.1
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• pp.101-106
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• 2001

Purpose : The outbreaks of measles in infants and school children have been reported recently, but there are no specific treatment of these patients except symptomatic therapy. This study was performed to evaluate the effectiveness of intravenous gammaglobulin(IVGG) therapy in acute febrile phase of measles. Methods : The 68 cases in measles were treated with single dose of IVGG(400~500 mg/kg), and 44 cases were treated with only symptomatic treatment during the periods of 14 months from Jan. 2000 to Feb. 2001. They were compared to duration of fever, rash, the levels of CRP and days of admission on both groups after treatment. Results : The results obtained follows. The average of age was $7.9{\pm}3.6$ year old, and male to female was 1.0 : 1.6. The duration of fever after admission was $2.4{\pm}1.2$ days in treated group and $5.7{\pm}2.4$ days in control group. The period of disappearance of systemic erythematous maculopapular rash was $4.5{\pm}1.3$ days in treated group, and $6.9{\pm}2.4$ days in control group. The durations of admission day were also shown significantly shorter duration of period in treated group(P<0.05). The levels of CRP were no significant difference between two groups before treatment. However, treated group was significantly shown by improved within 5 days after IVGG therapy(P<0.05). Conclusions : The single dose of IVGG(400~500 mg/kg) therapy is one of rapid and effective therapy for clinical symptoms and signs in acute high febrile phase of measles.

• Pediatric Infection and Vaccine
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• v.7 no.2
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• pp.218-224
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• 2000

Purpose : In Korea, vivax malaria has been reemerged since 1993 after being abscent for more than 10 years. There are several possibilities of casuality of recent epidemic, although it is still unclear. The epidemiologic studies including case analysis and entomological reseach have been undertaken for a successful control measure. But, unfortunately those studies have been rarely dealt with cases of children. Therefore, this study was designed to figure out the characteristics of epidemiolgic and clinical features in children with indigenous vivax malaria. Methods : The study 21 cases below 15 years of age, who were diagnosed as vivax malaria and resided in kyounggi-do province area during 1998. 9~1999. 8. We retrospectively analyzed epidemiologic data concernig with occurrence of vivax, and clinical manifestations, abnormal laboratory findings and outcomes including therapeutic responses. Results : All cases were inhabitants of the endemic areas for vivax malaria in northwestern part of Kyonggi-do or western Kangwon-do, and Paju-gun was the most prevalent. Indigenous malaria cases of this study were more prevalent in children above 10 years old age, and in male. Seasonally, vivax malaria in children occurred throughout the year except January, March and November, and the incidence was the highest in July. Clinical manifestations revealed that 48 hour cyclic fever pattern was the major fever pattern, and other symptoms such as headache, vomiting, poor appetites, chilling, abdominal pain and diarrhea were concomitantly developed. And splenomegaly revealed the main abnormal findings on physical examination, and anemia was the most frequent abnormal finding in laboratory examinations. Young trophozoite was frequently observed on peripheral blood smears. The therapeutic responses of chlorquine were very good in all cases, and no recurrence developed in follow up cases. Conclusion : Geographical and seasonal occurrence distributions of indigenous vivax malaria cases in children were very similar to those of adults as followings; Inhabitants of the endemic region, more prevalent in male, and more common during the summer season. Clinically, 48 hour cyclic fever pattern, splenomegaly and anemia were most frequent and important manifestations in children cases, and clinical courses were not serious. On blood smears, young trophozoite was most dominantly examined in children. Generally, the therapeutic outcomes were excellent, and recurrences were not observed.

• Pediatric Infection and Vaccine
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• v.5 no.1
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• pp.104-114
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• 1998

Purpose : Enteroviruses are the most common cause of aseptic meningitis. The epidemics of aseptic meningitis in 1993 and 1996 were mostly caused by echovirus type 9. Identification of the causative virus of aseptic meningitis in epidemics, is very important not only for diagnosis but also for epidemiologic purpose. The purpose of this study was to identify the causative virus and investigate the relationship between aseptic meningitis, prevailed in Masan and surrounding areas in Kyoungsangnamdo in 1997, and its clinical manifestations. Methods : One hundred twenty eight cerebrospinal fluid(CSF) and 239 stool specimens were obtained from 239 patients(213 children and 26 adult patients) with aseptic meningitis were admitted to Masan Fatima Hospitals from March to October 1997. Viral isolation and serotype identification was performed by cell culture and immunofluorescent test. Enteroviruses not typed by immunofluorescent test was confirmed by reverse transcription-polymerase chain reaction(RT-PCR). Results : 1) The peak incidence was noted in June. 2) The age of 239 patients(pediatrics-213 cases, internal medicine-26 cases) that were diagnosed ranged from neonate to 35 years, the age of the patients of pediatrics ranged from neonate to 15years(mean 4.9 years), the age of the patients of internal medicine (above 16 years) ranged from 16 years to 35 years(mean 24.2 years). 3) Fifty-three(41.4%) of 128 CSF specimens were positive for enteroviruses, and 163(68.2%) of 239 stool specimens were positive for enteroviruses respectively. 4) Serotypes of 53 enteroviruses isolated from CSF were 16(30.2%) of echovirus type 30, 6(11.3%) of echovirus type 6, 1 of echovirus type 4, 4 of untyped echovirus, 1 of coxsackievirus type B5, and 24 isolates of untyped enteroviruses. Of 163 enterovirus isolated from stool were 72(44.2%) of echovirus type 30, 21(12.9%) of echovirus type 6, 1 of echovirus type 4, 17(10.4%) of undetermined subtyped echovirus, 1 of coxsackievirus type B5, 2 of A24, 3 of undetermined subtyped coxsackievirus type B, and 46 isolates of untyped enterovirus. Conclusion : There were epidemics of aseptic meningitis in the central areas of Kyoungsangnamdo from March to October 1997. The main causative organism was thought to be the echovirus type 30, and echovirus type 4, 6, coxsackievirus B5 and A24 were also thought to contribute to the epidemics.