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Haesun Yun 3 Articles
Seroepidemiology of Hepatitis A Infection in Northeastern China, Korea, and Japan
Haesun Yun, Hyeok-Jin Lee, Youngsil Yoon, Kisang Kim, Sungsoo Kim, Myung-Hee Shin, Miyuki Taniguchi, Soo Ryang Kim, Mi Kyung Kim
Osong Public Health Res Perspect. 2012;3(1):31-35.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2012.01.005
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  • 4 Citations
AbstractAbstract PDF
Objectives
The epidemiological patterns of endemic hepatitis A virus (HAV) are unclear in northeastern Asia depending on the ethnicity of the country in question. The purpose of this study was to investigate the seroprevalence of HAV in northeastern China, South Korea, and Japan.
Methods
A total of 1,500 serum samples were collected from five groups of inhabitants (300 each) who were over 40 years of age (Korean Chinese, indigenous Chinese, South Korean, Korean living in Japan, and indigenous Japanese). The samples were screened for antibodies to HAV using an enzyme-linked immunosorbent assay.
Results
Positivity for HAV antibodies was 93.7% (95% confidence interval [CI]: 90.9–96.4) in Koreans living in northeastern China, 99.7% (95% CI: 99.0–100.3) in indigenous Chinese, 98.0% (95% CI: 96.4–99.6) in indigenous Koreans, 33.3% (95% CI: 28.0–38.7) in Koreans living in Japan, and 20.4% (95% CI: 15.8–25.0) in indigenous Japanese persons. The overall anti-HAV prevalence was not significantly different between northeastern China and South Korea, but it was different in Japan.
Conclusions
These results indicate that differences in seroprevalence can be attributed to geological, environmental, and socioeconomic conditions rather than ethnicity.
Cyclophilin A Cpr1 Protein Modulates the Response of Antioxidant Molecules to Menadione-induced Oxidative Stress in Saccharomyces cerevisiae KNU5377Y
Il-Sup Kim, Haesun Yun, Ingnyol Jin, Ho-Sung Yoon
Osong Public Health Res Perspect. 2011;2(3):171-177.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.041
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AbstractAbstract PDF
Objectives
The cellular function of cyclophilin A (CypA) differs between organisms, even though CypA is conserved in both prokaryotes and eukaryotes. The purpose of this study was to elucidate the role of activated CypA isoform CPR1 in the antioxidative mechanisms of Saccharomyces cerevisiae under menadione (MD)-induced oxidative stress.
Methods
Four S. cerevisiae strains, KNU5377Y (kwt) and BY4741 (bwt), and their isogenic cpr1⊿ mutant strains (kc1 and bc1), were treated with MD, at a concentration ranging between 0.25 and 0.4 mM. Cpr1-mediated antioxidative effects were analyzed by measuring the levels of cellular glutathione (GSH) and ascorbate (AsA)-like molecules in yeast.
Results
GSH and AsA-like reductant molecule concentrations were more reduced in the presence of MD in the kc1 strain than in the kwt strain; whereas, there was no significant difference between the bwt and bc1 strains under the same conditions. In kc1 strain samples, we observed a reduction in the expression of proteins related both to GSH synthesis and the recycling system, and simultaneously, downregulation of GSH synthetase and GSH reductase activities were also evident. Oxidative stress in the kc1 strain was alleviated by the application of the GSH and AsA analog.
Conclusion
These results indicate that activated Cpr1 modulates the response of antioxidant molecules involved in cellular redox homeostasis of KNU5377Y during oxidative stress induced by MD.
Seroprevalence of Hepatitis A and E Viruses Based on the Third Korea National Health and Nutrition Survey in Korea
Haesun Yun, Hyeok-Jin Lee, Doosung Cheon, Chaeshin Chu, Kyung Won Oh, Young Taek Kim, Youngmee Jee
Osong Public Health Res Perspect. 2011;2(1):46-50.   Published online June 30, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.04.009
  • 1,681 View
  • 12 Download
  • 7 Citations
AbstractAbstract PDF
Objectives
The purpose of this study was to investigate the seroprevalence of hepatitis A virus (HAV) and hepatitis E virus (HEV) in Korea during 2005.
Methods
Study subjects were selected from across Korea using a stratified multistage probability sampling design, and HAV and HEV seroprevalence was compared on the basis of sex, age, and residency. A total of 497 rural and urban people aged 10–99 years of age (mean ± SD age = 28.87 ± 17.63 years) were selected by two-stage cluster sampling and tested serologically for anti-HAV and anti-HEV IgG using an enzyme-linked immunosorbent assay.
Results
Among this population, the overall seroprevalence of HAV was 63.80% (55.21% aged in their 20s and 95.92% in their 30s, p < 0.01) and that of HEV was 9.40% (5.21% aged in their 20s and 7.14% in their 30s, p < 0.01). Seroprevalence also varied according to area of residence. HEV prevalence in rural areas was higher than that of urban regions based on the anti-HEV antibody, odds ratio 3.22 (95% confidence interval: 1.46–7.10, p < 0.01). There were no significant differences between male and female against anti-HAV/HEV antibodies.
Conclusion
Our study suggested that the seropositive rates of HAV and HEV might be related to age and environmental conditions.

PHRP : Osong Public Health and Research Perspectives