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Volume 2(3); December 2011
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Articleses
Is the Public Transportation System Safe from a Public Health Perspective?
Hae-Wol Cho, Chaeshin Chu
Osong Public Health Res Perspect. 2011;2(3):149-150.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.037
  • 1,283 View
  • 22 Download
  • 1 Citations
PDF
Neutralizing Antibody Responses and Evolution of the Viral Envelope in the Course of HIV-1 Korean Clade B Infection
Bo Gyeong Shin, Mi-Ran Yun, Sung Soon Kim, Gab Jung Kim
Osong Public Health Res Perspect. 2011;2(3):151-157.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.038
  • 1,282 View
  • 19 Download
  • 1 Citations
AbstractAbstract PDF
Objectives
HIV is able to continuously adapt to and evade the evolving neutralizing antibody responses of the host. We investigated the ability of HIV variants to evade neutralizing antibodies in order to understand the distinct characteristics of HIV-1 Korean clade B.
Methods
Three drug-naive subjects were enrolled in this study who were infected with HIV-1 Korean clade B. Neutralizations were performed using autologous plasma and pseudovirion-based assays in order to analyze and compare changes in the env gene.
Results
In the early phase of infection, neutralizing activities against autologous virus variants gradually increased, which was followed by a decline in the humoral immune response against the subsequent viral escape variants. The amino acids lengths and number of potential N-linked glycosylation sites (PNGS) in HIV-1 env gene was positively correlated with neutralized antibody responses during the early stages of infection.
Conclusion
This study suggests that change within the env domains over the course of infection influences reactivities to neutralized antibodies and may also have an impact on host immune responses. This is the first longitudinal study of HIV-1 humoral immunity that took place over the entire course of HIV-1 Korean clade B infection.
Longitudinal and Cross-Sectional Genetic Diversity in the Korean Peninsula Based on the P vivax Merozoite Surface Protein Gene
Jung-Yeon Kim, Eun-Jung Suh, Hyo-Soon Yu, Hyun-Sik Jung, In-Ho Park, Yien-Kyeoug Choi, Kyoung-Mi Choi, Shin-Hyeong Cho, Won-Ja Lee
Osong Public Health Res Perspect. 2011;2(3):158-163.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.039
  • 1,188 View
  • 15 Download
  • 4 Citations
AbstractAbstract PDF
Objectives
Vivax malaria has reemerged and become endemic in Korea. Our study aimed to analyze by both longitudinal and cross-sectional genetic diversity of this malaria based on the P vivax Merozoite Surface Protein (PvMSP) gene parasites recently found in the Korean peninsula.
Methods
PvMSP-1 gene sequence analysis from P vivax isolates (n = 835) during the 1996-2010 period were longitudinally analyzed and the isolates from the Korean peninsula through South Korea, the demilitarized zone and North Korea collected in 2008-2010 were enrolled in an overall analysis of MSP-1 gene diversity.
Results
New recombinant subtypes and severe multiple-cloneinfection rates were observed in recent vivax parasites. Regional variation was also observed in the study sites.
Conclusion
This study revealed the great complexity of genetic variation and rapid dissemination of genes in P vivax. It also showed interesting patterns of diversity depending, on the region in the Korean Peninsula. Understanding the parasiteninsula. Under genetic variation may help to analyze trends and assess the extent of endemic malaria in Korea.
Alterations of gyrA, gyrB, and parC and Activity of Efflux Pump in Fluoroquinolone-resistant Acinetobacter baumannii
Sunok Park, Kyeong Min Lee, Yong Sun Yoo, Jung Sik Yoo, Jae Il Yoo, Hwa Su Kim, Yeong Seon Lee, Gyung Tae Chung
Osong Public Health Res Perspect. 2011;2(3):164-170.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.040
  • 1,275 View
  • 14 Download
  • 25 Citations
AbstractAbstract PDF
Objectives
This study investigated the fluoroquinolone-resistant mechanism of 56 clinical cases of A baumannii infection from 23 non-tertiary hospitals, collected between 2004 and 2006.
Methods
Susceptibility testing was performed by broth microdilution and Epsilometer test. Analyses of quinolone resistance-determining region (QRDR) were done by sequencing. The activity of the efflux pump was measured using inhibitors.
Results
The sequences from selected 56 isolates were divided into seven groups (I-VII) on the basis of mutations in gyrA (S83L), parC (S80L, S80W and S84K) and gyrB (containing the novel mutations E679D, D644Y and A677V). The 27 isolates with triple mutations in gyrA, gyrB and parC (groups IV-VII) showed higher levels of resistance to ciprofloxacin (minimal inhibitory concentration [MIC] of 16-256 μg/mL) than the 26 isolates with double mutations in gyrA and parC (groups II and III, MIC of 8-64 μ g/mL; p < 0.05). Alterations in the efflux pump were observed in four isolates with the parC S80L mutation (group II) or E84K mutation (group VII), but no effect was observed in an isolate with the parC S80 W mutation (group III).
Conclusion
These results suggest that triple mutations in clinical isolates of A baumannii contribute to the development of high levels of resistance to fluoroquinolones and that mutations in parC S80L or E84K (groups II and VII) may contribute to alterations in efflux pump activity in A baumannii.
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
  • 1,165 View
  • 13 Download
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.
The Emergence of Oseltamivir-Resistant Seasonal Influenza A (H1N1) Virus in Korea During the 2008-2009 Season
Woo-Young Choi, Inseok Yang, Sujin Kim, Namjoo Lee, Meehwa Kwon, Joo-Yeon Lee, Chun Kang
Osong Public Health Res Perspect. 2011;2(3):178-185.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.042
  • 1,272 View
  • 12 Download
  • 10 Citations
AbstractAbstract PDF
Objectives
To monitor antiviral drug resistance among seasonal influenza viruses isolated in Korea during the 2008-2009 influenza season, we examined influenza isolates collected through Korea Influenza Surveillance Scheme for antiviral drug susceptibility.
Methods
For genetic analysis of antiviral drug resistance, the matrix (M2) and neuraminidase (NA) genes of each isolate were amplified by reverse transcription-polymerase chain reaction and followed by nucleotide sequencing. For phylogenetic analyses, the sequences of hemagglutinin (HA) and NA genes of each isolate were aligned using multiple alignment program. For phenotypic analysis of antiviral drug resistance, drug susceptibilities against M2 inhibitor (amantadine) and NA inhibitors (oseltavimir and zanamivir) were determined by virus yield reduction assay and fluorometric NA inhibition assay, respectively.
Results
In Korea, the resistant influenza viruses against oseltamivir were first detected in sealsonal influenza A(H1N1) viruses on Week 48 of 2008. Since then, the number of oseltamivir-resistant A(H1N1) viruses was continuously increased and had reached the highest peak on Week 52 of 2008. 533 (99.8%) of 534 A(H1N1) viruses were resistant to oseltamivir and all of them harbored the H275Y mutation in the NA gene during the 2008-2009 season. The oseltamivir resistance identified by sequencing was confirmed by NA inhibition assay. Genetic analysis based on HA gene of the resistant A(H1N1) viruses revealed that the viruses were identified as A/Brisbane/10/2007-like strain which was vaccine strain for the 2008-2009 season.
Conclusions
The oseltamivir-resistant A(H1N1) viruses were first emerged in Europe in November 2007 and then circulated globally. One year later, the oseltamivir-resistant A(H1N1) viruses were first detected in Korea in November 2008 and continued circulating until the Week 7 of 2009 during the 2008-2009 season. Considering the pandemic preparedness, it should be continued to monitor the emergence and the characterization of antiviral drug resistant influenza viruses.
Serum MicroRNA Expression Profiling in Mice Infected with Rabies Virus
Myung Guk Han, Jun-Sun Park, Cho Soon Lee, Young Eui Jeong, Jung Sang Ryou, Jung Eun Cho, Young Ran Ju, Kyoung-Ki Lee
Osong Public Health Res Perspect. 2011;2(3):186-191.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.043
  • 1,491 View
  • 18 Download
  • 6 Citations
AbstractAbstract PDF
Objectives
Serum or plasma microRNAs (miRNAs) are potential biomarkers for the diagnosis for cancer and prenatal diseases. This study was conducted to investigate whether rabies virus causes a change in serum miRNA expression.
Methods
ICR mice were intramuscularly inoculated with rabies virus and were sacrificed weekly to collect serum and brain tissue for 4 weeks postinoculation. Mice were assigned to four groups based on the results of indirect immunofluorescent assays, enzyme-linked immunosorbent assay, and nested reverse transcription-polymerase chain reaction and the expression profiles of serum miRNAs were compared using a commercial mouse miRNA expression profiling assay.
Results
The expression levels of miRNAs changed significantly with the different stages of the disease. The expression level of 94 serum miRNAs in infected mice changed at least twofold. Seven microRNAs of them were significantly upregulated or downregulated in all infected mice regardless of disease status. The number of miRNAs with an expression level change decreased with the progression of the disease. In a hierarchical cluster analysis, infected mice clustered into a group separate from uninfected control mice.
Conclusions
Based on the relationship of miRNAs to gene expression regulation, miRNAs may be candidates for the study of viral pathogenesis and could have potential as biomarkers.
Food and Nutrient Intakes According to Income in Korean Men and Women
Inyoung Hur, Myoung-Jin Jang, Kyungwon Oh
Osong Public Health Res Perspect. 2011;2(3):192-197.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.044
  • 1,298 View
  • 17 Download
  • 14 Citations
AbstractAbstract PDF
Objectives
The present study investigated associations between income and intake of nutrients and food in adults (n = 11,063) from the fourth Korea National Health and Nutrition Examination Survey 2007–2009.
Methods
To examine relationships between individual dietary intake and anthropometric measures and family income, multiple linear regression models were constructed for each outcome variable. All models were adjusted for age, education, energy intake, smoking, body mass index, and physical activity.
Results
For men, intakes of protein, calcium, phosphorus, potassium, and vitamin C were lower in low-income compared to high-income groups. For women, intakes of protein and niacin were lower in low-income groups. Lowest income group ate less dairy products in men and less fruits and fishes or shellfishes in women.
Conclusion
Low-income groups had severe food insecurity and low diet quality compared to high-income groups. The study results will provide direction for public health efforts regarding dietary intakes according to economic status among Korean men and women.
Prevalence of Farm and Slaughterhouse Workers Carrying Shiga Toxin-Producing Escherichia coli in Korea
Sahyun Hong, Seung Eun Song, Kyung Hwan Oh, Seung Hak Kim, Seok ju Yoo, Hyun Sul Lim, Mi Sun Park
Osong Public Health Res Perspect. 2011;2(3):198-201.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.045
  • 1,223 View
  • 13 Download
  • 1 Citations
AbstractAbstract PDF
Objectives
The aim of this study was to investigate the distribution of Shiga toxin (Stx) gene-positive stool samples from dairy farmer and slaughterhouse workers in Gyeonggi-Do province.
Methods
A total of 621 samples from healthy farmers and 198 samples from slaughterhouse workers were screened by polymerase chain reaction (PCR) for Shiga toxigenic Escherichia coli (STEC) infection on stool samples.
Results
The PCR product of Stx-encoding genes was detected in 21 (3.4%) of 621 farmers and 15 (7.6%) of 198 slaughterhouse workers’ stool samples. Distribution of the Stx PCR positive workers by age increment revealed an increase in STEC infection with age increment in both workers. Distribution of the Stx PCR positive workers by working years revealed an increase in STEC infection with working years in farmers.
Conclusion
These results of the study show that slaughterhouse workers are at higher risk of STEC infection than farmers. In addition, slaughterhouse workers have a more potential source of food contamination of STEC and transmission.
A diversity of Antibiotic-resistant Staphylococcus spp. in a Public Transportation System
Pamela J. Yeh, Dawn M. Simon, Jess A. Millar, H. Forrest Alexander, Darleen Franklin
Osong Public Health Res Perspect. 2011;2(3):202-209.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.047
  • 1,890 View
  • 16 Download
  • 10 Citations
AbstractAbstract PDF
Objectives
Our goal was to determine the diversity and abundance of Staphylococcus bacteria on different components of a public transportation system in a mid-sized US city (Portland, Oregon) and to examine the level of drug resistance in these bacteria.
Methods
We collected 70 samples from 2 cm × 4 cm sections from seven different areas on buses and trains in Portland, USA, taking 10 samples from each area. We isolated a subset of 14 suspected Staphylococcus spp. colonies based on phenotype, and constructed a phylogeny from16S rRNA sequences to assist in identification. We used the Kirbye–Bauer disk diffusion method to determine resistance levels to six common antibiotics.
Results
We found a range of pathogenic Staphylococcus species. The mean bacterial colony counts were 97.1 on bus and train floors, 80.1 in cloth seats, 9.5 on handrails, 8.6 on seats and armrests at bus stops, 3.8 on the underside of seats, 2.2 on windows, and 1.8 on vinyl seats per 8 cm2 sample area. These differences were significant (p < 0.001). Of the 14 isolates sequenced, 11 were staphylococci, and of these, five were resistant to penicillin and ampicillin, while only two displayed intermediate resistance to bacitracin. All 11 isolates were sensitive to trimethoprim-sulfamethoxazole, vancomycin, and tetracycline.
Conclusions
We found six different strains of Staphylococcus, and while there were varying levels of drug resistance, we did not find extensive levels of multidrug-resistant bacteria, and no S. aureus was found. We found floors and cloth seats to be areas on buses and trains that showed particularly high levels of bacteria.
Sensitivity Analysis of the Parameters of Korea’s Pandemic Influenza Preparedness Plan
Chaeshin Chu, Junehawk Lee, Dong Hoon Choi, Seung-Ki Youn, Jong-Koo Lee
Osong Public Health Res Perspect. 2011;2(3):210-215.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.048
  • 1,368 View
  • 16 Download
  • 10 Citations
AbstractAbstract PDF
Objectives
Our aim was to evaluate Korea’s Pandemic Influenza Preparedness Plan.
Methods
We conducted a sensitivity analysis on the expected number of outpatients and hospital bed occupancy, with 1,000,000 parameter combinations, in a situation of pandemic influenza, using the mathematical simulation program InfluSim.
Results
Given the available resources in Korea, antiviral treatment and social distancing must be combined to reduce the number of outpatients and hospitalizations sufficiently; any single intervention is not enough. The antiviral stockpile of 4–6% is sufficient for the expected eligible number of cases to be treated. However, the eligible number assumed (30% for severe cases and 26% for extremely severe cases) is very low compared to the corresponding number in European countries, where up to 90% of the population are assumed to be eligible for antiviral treatment.
Conclusions
A combination of antiviral treatment and social distancing can mitigate a pandemic, but will only bring it under control for the most optimistic parameter combinations.
A Contribution of MdfA to Resistance to Fluoroquinolones in Shigella flexneri
Jun-Young Kim, Se-Mi Jeon, Hyungjun Kim, Mi-Sun Park, Seong-Han Kim
Osong Public Health Res Perspect. 2011;2(3):216-217.   Published online December 31, 2011
DOI: https://doi.org/10.1016/j.phrp.2011.11.049
  • 1,288 View
  • 16 Download
  • 7 Citations
AbstractAbstract PDF
In this study, we measured the drug resistance conferred by mdfA mutations in two Shigella flexneri strains. A mutant in mdfA genes was constructed by polymerase chain reaction–based, one-step inactivation of chromosomal genes. The antimicrobial susceptibility of parent and mutant strains to fluoroquinolones was determined by minimal inhibitory concentration (MICs). The △mdfA mutants were somewhat more susceptible to fluoroquinolones than the parent strains. The low level changes in MICs of the △mdfA mutants suggest that mdfA contributed the fluoroquinolone resistance in S flexneri. This finding found that the increased expression level of an MdfA efflux pump mediated fluoroquinolone resistance, but it is not likely a major effecter of higher resistance levels.

PHRP : Osong Public Health and Research Perspectives