• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.155-167
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• 1997

The identification of serum HBV DNA is very important for the assessment of the disease activity in persistent infection, for the evaluation of the infectivity of an individuals blood. The dot blot, however, has limited sensitivity and sometimes inconsistent with other serological markers and clinical settings. Using the most important recent advance in molecular biology, the polymerase chain reaction(PCR), specific DNA sequences can be amplified more than a million-fold in a few hours and with this technique the detection of the extreme low level of DNA is possible. This study was to determine sensitivity of the PCR for the detection of serum HBV DNA in comparison with dot blot analysis and to investigate the serum HBV DNA status and clinical significance of PCR in patients with chronic HBsAg positive liver disease. The subjects of this study were 17 patients with asymptomatic HBsAg carriers(9 HBeAg positive patients, 8 anti-HBe positive patients), 91 chronic hepatitis B(50 HBeAg positive patients, 41 anti-HBe positive patients), 57 liver cirrhosis(21 HBeAg positive patients, 36 anti-HBe positive patients), 27 hepatocellular carcinoma(10 HBeAg positive patients, 17 anti-HBe positive patients). The results were summerized as following; The detection rates of HBV DNA by dot blot, PCR were 58.9%, 72.2% in HBeAg positive patients, 34.3%, 53.9% in anti-HBe positive patients. The detection rates of HBV DNA by PCR in HBeAg negative patients were 25.0% in asymptomatic HBsAg carriers, 61.0% in chronic hepatitis B, 52.8% in liver cirrhosis, 52.9% in hepatocellular carcinoma. The positive rate for HBV DNA is a significant difference between HBeAg positive and negative asymptomatic HBsAg carriers, but not significantly difference in other groups. In conclusions, this study confirmed that the PCR is much more sensitive than the dot blot analysis in detecting the HBV DNA in the sera of patients with chronic liver disease. The presence of HBV DNA in the serum was detected by PCR with higher sensitivity and it suggested that active viral replication is still going on in most patients with chronic HBsAg positive liver disease irrespective of HBeAg/anti-HBe status, and PCR may be used as a prognostic factor in asymptomatic HBsAg carriers.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.121-129
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• 1987

To evealuate the status of hepatitis B virus infection in the mothers and neonates and to determine the maternal-neonatal transmission of hepatitis B virus, 2,276 term pregnant women were screened for the presence of serum HBsAg, at the Department of Obstetrics and Gynecology, Yeungnam University Hospital, during the period of 18 months from Jan. 1986 to Jun. 1987, and the sera of sixty-six HBsAg carrier mothers and their neonates were tested for HBV markers and liver enzymes. The results were as follows : 1. The prevalence rate of asymptomatic HBsAg carrier in the term pregnant women was 4.7%(53/1,279). 2. Positive rates of HBsAg and anti-HBs 10 the sera of sixty-six neonates born to asymptomatic HBsAg carrier mothers were 12.1% and 9.1%, respectively. Transient elevation of SGOT(three to four times of upper normal limit) was detected in one of eight HBsAg-positive neonates and one of six anti-HBs positive neonates. 3. Positive rates of anti-HBc, HBeAg and anti-HBe to the sera of sixty-six asymptomatic HBsAg carrier term pregant women were 93.9%, 45.5% and 50%, respectively. The rates of transmission of maternal anti-HBc, HBeAg and anti-HBe to the neonates were 85.5%(53/62), 90%(27/30) and 87.9%(29/33). respectively. 4. Serum HBsAg was detected in four of thirty neonates born to HBeAg positive HBsAg carrier mother, three of thirty-three neonates born to anti-HBe positive HBsAg carrier mothers, and one of three neonates born to both HBeAg and anti-HBe negative HBsAg carrier mothers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.2
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• pp.129-136
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• 1991

Dry matter productivity at silage stage of two corn hybrids varying resistance to rice blackstreaked dwarf virus(RBSDV) and two sorghum hybrids varying growth duration was evaluated at six planting dates (Apr. 1, Apr. 15, Apr. 29, May 13, May 27, and June 10) in Kyongsan where RBSDV is prevalent.Corn was harvested 38-40 days after silking. For sorghum 1st-cut was made 19-22 days after heading and some regrowth (2nd-cut) on October 13. 1. Percent stand of both corn hybrids was over 91% at all planting dates, but that of sorghum ranged 37.2-80.3% depending on hybrids and planting dates. 2. The number of days from planting to emergence decreased as planting date delayed in both crops. The number of days from emergence to silking of both corn hybrids and a sorghum hybrid(P 956) decreased as planting date delayed, but that of the other sorghum hybrid(P 931) increased significantly after May 13 planting. 3. RBSDV infection rate of corn hybrids was highest at April 1 planting (Kwanganok 24.896, Jinjuok 63.0%) and decreased up to April 29 planting and then increased as planting date delayed. Sorghum was not infected by RBSDV at all. 4. EarfTotal dry matter ratio of corn ranged 30.6-47.9% and that of sorghum 3.1-30.7% depending on hybrids and planting dates. All the hybrids developed grain normally at all planting dates except a sorghum hybrid (P 931) which developed few grains after May 13 planting. 5. Crude (C) protein and C. fat contents were similar among all treatments. C. fiber content of P 931 was higher than that of both corn hybrids and P 956, but nitrogen free extract (NFE) was lower. C. fiber and NFE of both corn hybrids and 1st-cut sorghum were similar among the planting dates, but C. fiber and NFE of 2nd-cut of sorghum decreased and C. protein increased as planting date delayed due to plants were younger. 6. Dry matter (DM) yield of all hybrids decreased as planting date delayed except Jinjuok of which yield was highest at April 29 planting. DM yield of corn was similar to 1st-cut sorghum, but lower than total DM yield of sorghum at April 1 and 15 plantings where regrowth yield was high.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.116-125
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• 1997

Purpose : Studies on the duration of immune response against Japanese encephalitis virus from recipients with JE vaccine (Nakayama-NIH strain) in Korea. Methods : To determinate the immune response and the duration of antibody against JE vaccine, 213 students were examined since 1994 using hemmaglutination inhibition test and plaque reduction neutralization test (PRNT). Results : 24 months after the first vaccination, haemmaglutination inhibition and neutralizing antibody maintained from the recipients 63.4% (>1:20) and 100% (>1:20), respectively. In April 1996, one dose booster to the same recipients those who were vaccinated in 1994, the GMT antibody for HI and PRNT titer were both increased from 1:11.6 to 1:13.2 and 1:275.7 to 1:348.1, respectively, after 6 months booster (after 30 months from the initial vaccination). This results showed that the antibody from the active immunity could be maintained more than 12 months after the initial vaccination. On the basis of these results, inactivated killed JE vaccine (Nakayama-NIH strain) using for preventing against JE purpose seems to produce antibody enough to protect against JE at present. Conclusions : Along with the results of this study demonstrating duration of antibody, the active immunization could be maintained as long as by initial vaccination of 2 doses, a single dose of booster vaccination made during a period of 1 month to 12 months and the successive booster vaccination by 2 or 3 year intervals. However, the immunization schedule should be concerned with both epidemiology of disease and the immune response of vaccinated individuals.

• Pediatric Infection and Vaccine
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• v.21 no.3
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• pp.199-206
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• 2014

Purpose: There has been little research regarding the effectiveness of oseltamivir for influenza B infections. We sought to identify the different clinical manifestations between patients treated with and without oseltamivir. Methods: We retrospectively studied the medical records of 72 inpatients or outpatients from two medical centers diagnosed with influenza B infections by either a rapid antigen test or multiplex reverse transcriptase PCR between January 2012 and July 2012. We compared gender, age, past medical history, admission period, total fever duration, fever duration after hospitalization, post-oseltamivir medication peak temperature, laboratory test, chest X-ray, antibiotic medication, and the presence of concomitant viral or bacterial infections. Results: The number of subjects in our study was 72 who were diagnosed with influenza B pneumonia, acute bronchitis, acute bronchiolitis, croup, and mean age was $3.6{\pm}2.8$ year old. The demographic characteristics and clinical manifestations of oseltamivir and the non-oseltamivir groups, including hospitalization period ($4.18{\pm}2.10$ vs $4.79{\pm}1.49$ days, P=.17) and total fever duration ($5.32{\pm}2.07$ vs $6.41{\pm}3.25$ days, P =.09), demonstrated no significant differences. Notably, the oseltamivir group did have significantly reduced usage of antibiotic treatment than the non-oseltamivir group (P=.04). When we limited our patient group to patients under the age of three, similar results were seen. The group prescribed oseltamivir within 48 hours of fever onset had less antibiotic usage, in addition to a shorter fever duration. Conclusion: Oseltamivir appeared to have no benefit in improving the clinical course. However, if it is prescribed within the first 48 hours of symptoms, it may be more effective.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.117-123
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• 2011

The purpose of this study was to evaluate and compare different elution and concentration methods for optimization of human rotavirus (HRV) detection method using real-time RT-PCR and cell culture techniques. The leafy vegetable samples (lettuce, Chinese cabbage) were artificially inoculated with HRV. Viruses were extracted from the vegetables by two different elution buffers, buffer A (100 mM Tris-HCl, 50 mM glycine, 3% beef extract, pH 9.5) and buffer B (250 mM Threonine, 300 mM NaCl, pH 9.5), and the extracted viruses were concentrated by filtration and PEG precipitation sequentially. To determine infectivity of the viruses, the viruses recovered from the samples were infected to the MA-104 cells, and integrated cell culture real-time RT-PCR was performed at 1, 48, 72, 96, 120, 144, 168 h post-infection (p.i.). The elution buffer A was more efficient in extracting the virus from the produce samples tested than the buffer B, 29.54% and 18.32% of recoveries, respectively. The sensitivity of real-time RT-PCR method was markedly improved when the virus was concentrated by the filtration method. When the viruses were eluted and concentrated by buffer A and filtration, respectively, the average recovery rate was approximately 51.89%. When the viruses recovered from samples were infected to MA-104 cell, infectious HRV was detected within 48 h p.i. by ICC/real-time RT-PCR, whereas cytopathic effects were not observed until 72 h p.i. The optimized detection method evaluated in this study could be useful for rapid and reliable detection of HRV in fresh produce products and applied for detection of other food-borne viruses.

• Pediatric Infection and Vaccine
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• v.5 no.2
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• pp.245-257
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• 1998

Purpose : Although hepatitis B vaccine has been available to general population in Korea since 1983, it was difficult to compare various types of hepatitis B virus(HBV) vaccines primarily due to the differences in vaccination schedule, dosage, test methods and seropositive antibody level. In this study we reviewed the results of previous studies published in Korea, which include antibody positive rates and antibody titers of various vaccines, and examined the immunogenicity of these HBV vaccines. Methods : Studies published in medical journals, university journals concerning antibody positive rates following hepatitis B vaccination were reviewed. Inclusion criteria were those studies in which seroprotective antibody rate of 10mIU/mL or the sample ratio unit of 10 RU were used as the cut-off value and in which the test methods were RIA or ELISA. Exclusion criteria were; 1) unclear or inconsistent vaccine dosage, 2) no record of antibody titers or seroconversion rate, 3) no defined antibody rate or ratio for positive rating and 4) the vaccination schedule other than 0-1-2 months or 0-1-6 months. Results : 23 out of 52 studies were subjected for the review for seroconversion rates. 1) As for the immunogenicity in each age group, the seroconversion rates of Hepaccine(Cheil Jedang) were 85.1% in infants, 83.3% in children and 62.7% in adults, indicating higher rates in infants and children compared to adults(P<0.01). The seroconversion rates of Hepavax(Korea Green Cross) were 84.7%, 81.1% and 90.8%, indicating higher rates in infants and adults compared to children(P<0.01). 2) The seroconversion rate of Hepavax was 85.6% with 0-1-6 mo. schedule, 78.5% with 0-1-2 mo. schedule with a statistically significant difference(P<0.01). 4) There was no difference of seroconversion rates between the two doses of Hepavax, $5{\mu}g$ and $10{\mu}g$ in infants and children. 5) In adults the seroconversion rates were 62.7% with Hepaccine, 90.8% with Hepavax, and 94.8% with Engerix-B(SmithKline Beecham). Conclusion : In Korea, the incidence of chronic hepatitis B is high and changing the schedule in vaccination cannot contribute to the increase of the serocoversion rate. And in order to maximize immunogenicity, more effective vaccines as well as more proper vaccination methods should be used.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.284-295
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• 2020

In December 2019, the first coronavirus disease- 2019 (COVID-19) patient was reported in Wuhan, Hubei Province, China. Since then, the number of patients who suffered severe acute respiratory syndrome caused by the novel Coronavirus (SARS-CoV-2 or 2019-nCoV) has increased dramatically in Korea. This new variant virus induces pulmonary diseases, including cough, sore throat, rhinorrhea, dyspnea, and pneumonia. Because SARS-CoV-2 is an RNA virus, real-time reverse-transcriptase PCR has been used widely to diagnose COVID-19. As the Korea Centers for Disease Prevention and Control (KCDC) and Ministry of Food & Drug Safety (MFDS) approved emergency use authorization, clinical specimens collected from COVID-19 patients and even healthy people have been clinically diagnosed by laboratory medicine. Based on a literature search, this paper reviews the epidemiology, symptoms, molecular diagnostics approved by KCDC, a current diagnosis of COVID-19 in the laboratories, the difference between molecular and serological diagnosis, and guidelines for clinical specimens. In addition, the Korean guidelines of biosafety for clinical laboratory scientists are evaluated to prevent healthcare-associated infection. The author's experience and lessons as clinical laboratory scientists will provide valuable insights to protect the domestic and international health community in this COVID-19 pandemic around the world.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.245-251
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• 2015

Objectives: Intrahepatic recurrence is the major cause of death among patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after curative surgical resection. Several approaches have been reported to decrease the recurrence rate. The objective of our study was to compare the clinical effects of transcatheter arterial chemoembolization (TACE) combined with interferon-alpha (IFN-${\alpha}$) therapy on recurrence after hepatic resection in patients with HBV-related HCC with that of TACE chemotherapy alone. Methods: We retrospectively analyzed the data from 228 patients who were diagnosed with HBV-related HCC and underwent curative resection between January 2001 to December 2008. The patients were divided into TACE (n = 126) and TACE-IFN-${\alpha}$ (n = 102) groups for postoperative chemotherapy. The TACE regimen consisted of 5-fluorouracil (5-FU), cisplatin (DDP), and the emulsion mixed with mitomycin C (MMC) and lipiodol. The recurrence rates, disease-free survival (DFS), overall survival (OS), and risk of recurrence were evaluated. Results: The clinicopathological parameters and adverse effects were similar between the 2 groups (P > 0.05). The median OS for the TACE-IFN-${\alpha}$ group (36.3 months) was significantly longer than that of the TACE group (24.5 months, P < 0.05). The 3-and 5-year OS for the TACE-IFN-${\alpha}$ group were significantly longer than those of the TACE group (P < 0.05) and the recurrence rate was significantly lower (P < 0.05). The TACE and IFN-${\alpha}$ combination therapy, active hepatitis HBV infection, the number of tumor nodules, microvascular invasion, liver cirrhosis, and the BCLC stage were independent predictors of OS and DFS. Conclusions: The use of the TACE and IFN-${\alpha}$ combination chemotherapy after curative hepatic resection safely and effectively improves OS and decreases recurrence in patients with HBV-related HCC who are at high risk. Our findings can serve as a guide for the selection of postoperative adjuvant chemotherapy for patients with HBV-related HCC who are at high risk of recurrence.

• Korean journal of applied entomology
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• v.25 no.2 s.67
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• pp.113-120
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• 1986

Soybeans collected from different locations in Korea were planted for tests of seed transmission of soybean mosaic virus (SMV). The percentage of seed transmission ranged from 20.5 to 29.5% in 14 seedlots including soybean cultivar Namhe and 12 to 19% in other 44 seedlots. However, no seed transmission of SMV was observed in soybean cultivar Younkiyongho. SMV was detected from embryo and cotyledon of soybean seeds. The infection of SMV was highly detected from premature seeds than from fully mature seeds, and higher from seeds harvested from plants infected before June 20 than plants infected around July 20 and August 20. No significant relationship was observed between seed transmission of SMV and mottling of seeds. The incidence of soybean mosaic disease followed by one month after peak of aphid population. The number of aphids was less on leaves of soybeans with short and dense trichomes whereas it was higher on leaves of soybean with long and sparse trichomes. Generally, the number of aphids was decreased on leaves with long and dense trichomes as the growth progressed. Soybean cultivar Columbus and 14 cultivars were susceptible, Chief and 14 cultivars were moderate, but Jangbaek and 17 other cultivars were resistant to SMV when inoculated with one isolate of SMV.