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Volume 6(4); August 2015
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Original Articles
Depression among Korean Adults with Type 2 Diabetes Mellitus: Ansan-Community-Based Epidemiological Study
Chan Young Park, So Young Kim, Jong Won Gil, Min Hee Park, Jong-Hyock Park, Yeonjung Kim
Osong Public Health Res Perspect. 2015;6(4):224-232.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.05.004
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  • 21 Citations
AbstractAbstract PDF
Objectives
There are an increasing number of studies being carried out on depression in patients with diabetes. Individuals with diabetes have been reported as having a higher prevalence of depression compared to those without diabetes. However, only a few studies involving Korean patients have been conducted. The aims of this study were to examine the prevalence of depression and to find various risk factors according to the degree of depression among Korean patients with Type 2 diabetes mellitus (T2DM).
Methods
An Ansan-community-based epidemiological study was conducted from 2005 to 2012. The total number of participants in this study was 3,540, from which patients with diabetes (n = 753) have been selected. The presence of depression was evaluated using the Beck Depression Inventory total score.
Results
The prevalence of depression was 28.8%. The mean age of participants was 55.5 ± 8.2 years. We divided the participants into three groups (without-depression, moderate-depression, and severe-depression groups) to examine the depression prevalence among Korean T2DM patients. The unemployed participants had 2.40 [95% confidence interval (CI) 1.21–4.76], the low-income participants had 2.57 (95% CI 1.52–4.35), the participants using an oral diabetes medicine or insulin had 2.03 (95% CI 1.25–3.32), the participants who are currently smoking had 2.03 (95% CI 1.10–3.73), and those without regular exercise had 1.91 (95% CI 1.17–3.14) times higher odds of depression in the severe-depression group, compared with the without-depression group.
Conclusion
There was a significant association between depression prevalence and diabetes, and we found various risk factors according to the degree of depression in Korean patients with T2DM.
Enteric Bacteria Isolated from Diarrheal Patients in Korea in 2014
Nan-Ok Kim, Su-Mi Jung, Hae-Young Na, Gyung Tae Chung, Cheon-Kwon Yoo, Won Keun Seong, Sahyun Hong
Osong Public Health Res Perspect. 2015;6(4):233-240.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.07.005
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  • 10 Citations
AbstractAbstract PDFSupplementary Material
Objectives
The aim of this study was to characterize the pathogens responsible for causing diarrhea according to season, region of isolation, patient age, and sex as well as to provide useful data for the prevention of diarrheal disease.
Methods
Stool specimens from 14,886 patients with diarrhea were collected to identify pathogenic bacteria from January 2014 to December 2014 in Korea. A total of 3,526 pathogenic bacteria were isolated and analyzed according to season, region of isolation, and the age and sex of the patient.
Results
The breakdown of the isolated pathogenic bacteria were as follows: Salmonella spp. 476 (13.5%), pathogenic Escherichia coli 777 (22.0%), Vibrio parahaemolyticus 26 (0.74%), Shigella spp. 13 (0.37%), Campylobacter spp. 215 (6.10%), Clostridium perfringens 508 (14.4%), Staphylococcus aureus 1,144 (32.4%), Bacillus cereus 356 (10.1%), Listeria monocytogenes 1 (0.03%), and Yersinia enterocolitica 10 (0.3%). The isolation rate trend showed the highest ratio in the summer season from June to September for most of the pathogenic bacteria except the Gram-positive bacteria. The isolation rate of most of the pathogenic bacteria by patient age showed highest ratio in the 0–19 year age range. For isolation rate by region, 56.2% were isolated from cities and 43.8% were isolated from provinces.
Conclusion
Hygiene education should be addressed for diarrheal disease-susceptible groups, such as those younger than 10 years, aged 10–19 years, and older than 70 years, and monitoring for the pathogens is still required. In addition, an efficient laboratory surveillance system for infection control should be continued.
Analysis on Time-Lag Effect of Research and Development Investment in the Pharmaceutical Industry in Korea
Munjae Lee, Mankyu Choi
Osong Public Health Res Perspect. 2015;6(4):241-248.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.07.001
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  • 13 Citations
AbstractAbstract PDF
Objectives
The aim of this study is to analyze the influence of the research and development (R&D) investment of pharmaceutical companies on enterprise value.
Methods
The period of the empirical analysis is from 2000 to 2012, considering the period after the influence of the financial crisis. Financial statements and comments in general and internal transactions were extracted from TS-2000 of the Korea Listed Company Association, and data related to stock price were extracted from KISVALUE-III of National Information and Credit Evaluation Information Service Co., Ltd. STATA 12.0 was used as the statistical package for panel analysis.
Results
In the pharmaceutical firms, the influence of the R&D intensity with regard to Tobin's q was found to be positive. However, only the R&D expenditure intensities of previous years 2 and 5 (t–2 and t–5, respectively) were statistically significant (p < 0.1), whereas those of previous years 1, 3, and 4 years (t–1, t–3, and t–4, respectively) were not statistically significant.
Conclusion
R&D investment not only affects the enterprise value but is also evaluated as an investment activity that raises the long-term enterprise value. The research findings will serve as valuable data to understand the enterprise value of the Korea pharmaceutical industry and to strengthen reform measures. Not only should new drug development be made, but also investment and support should be provided according to the specific factors suitable to improve the competitiveness of each company, such as generic, incrementally modified drugs, and biosimilar products.
Impact of Corporate Governance on Research and Development Investment in the Pharmaceutical Industry in South Korea
Munjae Lee
Osong Public Health Res Perspect. 2015;6(4):249-255.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.07.003
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  • 3 Citations
AbstractAbstract PDF
Objectives
The purpose of this study is to analyze the influence of the corporate governance of pharmaceutical companies on research and development (R&D) investment.
Methods
The period of the empirical analysis is from 2000 to 2012. Financial statements and comments in general, and internal transactions were extracted from TS-2000 of the Korea Listed Company Association. Sample firms were those that belong to the medical substance and drug manufacturing industries. Ultimately, 786 firm-year data of 81 firms were included in the sample (unbalanced panel data).
Results
The shareholding ratio of major shareholders and foreigners turned out to have a statistically significant influence on R&D investment (p < 0.05). No statistical significance was found in the shareholding ratio of institutional investors and the ratio of outside directors.
Conclusion
The higher the shareholding ratio of the major shareholders, the greater the R&D investment. There will be a need to establish (or switch to) a holding company structure. Holding companies can directly manage R&D in fields with high initial risks, and they can diversify these risks. The larger the number of foreign investors, the greater the R&D investment, indicating that foreigners directly or indirectly impose pressure on a manager to make R&D investments that bring long-term benefits.
Expression of Recombinant pET22b-LysK-Cysteine/Histidine-Dependent Amidohydrolase/Peptidase Bacteriophage Therapeutic Protein in Escherichia coli BL21 (DE3)
Hamed Haddad Kashani, Rezvan Moniri
Osong Public Health Res Perspect. 2015;6(4):256-260.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.08.001
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  • 17 Citations
AbstractAbstract PDF
Objectives
Bacteriophage-encoded endolysins are a group of enzymes that act by digesting the peptidoglycan of bacterial cell walls. LysK has been reported to lyse live staphylococcal cultures. LysK proteins containing only the cysteine/histidine-dependent amidohydrolase/peptidase (CHAP) domain has the capability to show lytic activity against live clinical staphylococcal isolates, including methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to clone and express LysK-CHAP domain in Escherichia coli BL21 (DE3) using pET22b as a secretion vector. The pET22b plasmid was used, which encoded a pelB secretion signal under the control of the strong bacteriophage T7 promoter.
Methods
The E. coli cloning strains DH5α and BL21 (DE3) were grown at 37°C with aeration in the Luria-Bertani medium. A plasmid encoding LysK-CHAP in a pET22b backbone was constructed. The pET22b vector containing LysK-CHAP sequences were digested with NcoI and HindIII restriction enzymes. Cloning accuracy was confirmed by electrophoresis. The pET22b-LysK plasmid was used to transform the E. coli strain BL21. Isopropyl β-d-1-thiogalactopyranoside (IPTG) was added to a final concentration of 1mM to induce T7 RNA polymerase-based expression. Finally, western blot confirmed the expression of target protein.
Results
In this study, after double digestion of pEX and pET22b vectors with HindIII and NcoI, LysK gene was cloned into two HindIII and NcoI sites in pET22b vector, and then transformed to E. coli DH5α. Cloning was confirmed with double digestion and analyzed with agarose gel. The recombinant pET22b-LysK plasmid was transformed to E. coli BL21 and the expression was induced by IPTG. The expression was confirmed by Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting method. Observation of a 28.5 kDa band confirmed LysK protein expression.
Conclusion
In the present study, LysK-CHAP domain was successfully cloned and expressed at the pET22b vector and E. coli BL21 (DE3).
Phenotypic Assays to Determine Virulence Factors of Uropathogenic Escherichia coli (UPEC) Isolates and their Correlation with Antibiotic Resistance Pattern
Mohsen Tabasi, Mohammad Reza Asadi Karam, Mehri Habibi, Mir Saeed Yekaninejad, Saeid Bouzari
Osong Public Health Res Perspect. 2015;6(4):261-268.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.08.002
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  • 35 Citations
AbstractAbstract PDF
Objectives
Urinary tract infection caused by uropathogenic Escherichia coli (UPEC) strains is one of the most important infections in the world. UPEC encode widespread virulence factors closely related with pathogenesis of the bacteria. The purpose of this study was to evaluate the presence of different phenotypic virulence markers in UPEC isolates and determine their correlation with antibiotic resistance pattern.
Methods
UPEC isolates from patients with different clinical symptoms of UTI were collected and screened for biofilm and hemolysin production, mannose resistant, and mannose sensitive hemagglutination (MRHA and MSHA, respectively). In addition, antimicrobial resistance pattern and ESBL-producing isolates were recorded.
Results
Of the 156 UPEC isolates, biofilm and hemolysin formation was seen in 133 (85.3%) and 53 (34%) isolates, respectively. Moreover, 98 (62.8%) and 58 (37.2%) isolates showed the presence of Types 1 fimbriae (MSHA) and P fimbriae (MRHA), respectively. Our results also showed a relationship between biofilm formation in UPEC isolated from acute cystitis patients and recurrent UTI cases. Occurrence of UTI was dramatically correlated with the patients' profiles. We observed that the difference in antimicrobial susceptibilities of the biofilm and nonbiofilm former isolates was statistically significant. The UPEC isolates showed the highest resistance to ampicillin, tetracycline, amoxicillin, and cotrimoxazole. Moreover, 26.9% of isolates were ESBL producers.
Conclusion
This study indicated that there is a relationship between the phenotypic virulence traits of the UPEC isolates, patients' profiles, and antibiotic resistance. Detection of the phenotypic virulence factors could help to improve understanding of pathogenesis of UPEC isolates and better medical intervention.
Middle East Respiratory Syndrome Coronavirus Outbreak in the Republic of Korea, 2015
Osong Public Health Res Perspect. 2015;6(4):269-278.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.08.006
Correction in: Osong Public Health Res Perspect 2016;7(2):138
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  • 165 Citations
AbstractAbstract PDF
Objectives
The outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the Republic of Korea started from the index case who developed fever after returning from the Middle East. He infected 26 cases in Hospital C, and consecutive nosocomial transmission proceeded throughout the nation. We provide an epidemiologic description of the outbreak, as of July 2015.
Methods
Epidemiological research was performed by direct interview of the confirmed patients and reviewing medical records. We also analyzed the incubation period, serial interval, the characteristics of superspreaders, and factors associated with mortality. Full genome sequence was obtained from sputum specimens of the index patient.
Results
A total of 186 confirmed patients with MERS-CoV infection across 16 hospitals were identified in the Republic of Korea. Some 44.1% of the cases were patients exposed in hospitals, 32.8% were caregivers, and 13.4% were healthcare personnel. The most common presenting symptom was fever and chills. The estimated incubation period was 6.83 days and the serial interval was 12.5 days. A total of 83.2% of the transmission events were epidemiologically linked to five superspreaders, all of whom had pneumonia at presentation and contacted hundreds of people. Older age [odds ratio (OR) = 4.86, 95% confidence interval (CI) 1.90–12.45] and underlying respiratory disease (OR = 4.90, 95% CI 1.64–14.65) were significantly associated with mortality. Phylogenetic analysis showed that the MERS-CoV of the index case clustered closest with a recent virus from Riyadh, Saudi Arabia.
Conclusion
A single imported MERS-CoV infection case imposed a huge threat to public health and safety. This highlights the importance of robust preparedness and optimal infection prevention control. The lessons learned from the current outbreak will contribute to more up-to-date guidelines and global health security.
Corrigendum
Corrigendum to “Exposure to Dichlorodiphenyltrichloroethane and the Risk of Breast Cancer: A Systematic Review and Meta-analysis [Volume 5, Issue 2, April 2014, Pages 77–84]”
Jae-Hong Park, Eun Shil Cha, Yousun Ko, Myung-Sil Hwang, Jin-Hwan Hong, Won Jin Lee
Osong Public Health Res Perspect. 2015;6(4):279-279.   Published online August 31, 2015
DOI: https://doi.org/10.1016/j.phrp.2015.07.004
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PHRP : Osong Public Health and Research Perspectives