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Song G.,Samkwang Medical Laboratories | Yoon K.,Konkuk University | Chi H.,Samkwang Medical Laboratories | Roh J.,Yonsei University | Kim J.,Cheongju University
Chronobiology International | Year: 2016

Working during the night can disrupt the normal circadian rhythm by altering the melatonin level. A low level of melatonin is associated with an increased risk of cancer, possibly by decreasing the expression of tumor-suppressor genes, such as p53. To determine whether nighttime work is associated with melatonin level in serum as well as the expression of related genetic markers, we enrolled 100 female nighttime medical technologists employed at a hospital in South Korea. Melatonin concentration and melatonin receptor 1 (MT1) expression were significantly lower in nighttime than in daytime workers (1.84 pg/mL versus 4.04 pg/mL; 1.16 versus 1.61, respectively). However, p53 expression showed no difference between the groups. In summary, nighttime work could be an important risk factor for circadian disruption, but not a direct risk factor for cancer in medical technologists in South Korea. © 2016 Taylor & Francis

Jeong B.-H.,Hallym University | Jeong B.-H.,Chonbuk National University | Kim H.-J.,Hallym University | Lee K.-H.,Samkwang Medical Laboratories | And 2 more authors.
Molecular Biology Reports | Year: 2014

Polymorphisms in the prion protein gene (PRNP) can affect the susceptibility of humans to prion diseases. Recently, aside from PRNP, single nucleotide polymorphisms (SNPs) of two candidate genes for susceptibility to human prion diseases have been identified by human genome-wide association studies (GWAS) in the British population. One SNP of retinoic acid receptor beta (RARB), which is correlated with prion disease incubation time in mice, was associated with human prion diseases such as variant and iatrogenic CJD in the British population. The other SNP of the gene that encodes SCG10 (STMN2), which is related to clinical onset of sporadic CJD, was also associated with variant CJD and kuru. In order to investigate whether two polymorphisms located in upstream of RARB and STMN2 are associated with sporadic CJD in the Korean population, we compared genotype and allele frequencies of these polymorphisms in 217 sporadic CJD patients and 216 healthy Koreans. The genotype distribution and allele frequencies in upstream of the RARB and STMN2 polymorphisms were not significantly different between healthy controls and Korean sporadic CJD patients. This finding indicates that the two SNPs are not correlated with genetic susceptibility to sporadic CJD in the Korean population. This is the first genetic association study of RARB and STMN2 with sporadic CJD in an Asian population. © 2014 Springer Science+Business Media Dordrecht.

Ryu H.,Catholic University of Korea | Park Y.-J.,Catholic University of Korea | Kim Y.-k.,Samkwang Medical Laboratories | Chang J.,Catholic University of Korea | Yu J.K.,Catholic University of Korea
Journal of Infection and Chemotherapy | Year: 2014

Streptococcus agalactiae has emerged as an important cause of invasive infection in adults. Forty-nine S. agalactiae isolates (41 from adults and 8 from neonates) were collected during a 4-year period (2010-2013) and analyzed by multilocus sequence typing (MLST). Antibiotic susceptibility to erythromycin, clindamycin and levofloxacin was determined and the determinants of resistance (ermA, ermB, ermC, mefA, lnuB) were detected by PCR and mutation in gyrA, gyrB, parC and parE gene was investigated by sequence analysis. They were resolved into 14 sequence types (STs) and belonged to five clonal complexes (CCs). The distribution of CC was significantly different according to the age group; CC1 (18/41) and CC10 (13/41) was the most common among the adult isolates but CC19 (5/8) was predominant among the neonatal isolates. The resistance rate to erythromycin, clindamycin was 18.4% and 24.5%, respectively. Among the 13 strains resistant to erythromycin and/or clindamycin, two isolates harbored ermA and 10 isolates harbored ermB. The levofloxacin resistance rate was very high (32.7%) and was significantly higher in CC10 (71.4%). All the levofloxacin-resistant isolates had identical gyrA substitution (Ser81Leu) but parC substitution was different according to the CCs. The additional mutation in parE (His221Tyr) was found only in CC19. Continuous monitoring of the fluoroquinolone resistance and genotypic distribution among S. agalactiae is needed. © 2014.

Yoon B.S.,Korea University | Moon J.-H.,Korea University | Jun E.K.,Korea University | Jun E.K.,Stemmedience Corporation | And 11 more authors.
Stem Cells and Development | Year: 2010

Recent evidence shows that amniotic fluid (AF) contains multiple cell types derived from the developing fetus, and may represent a novel source of stem cells for cell therapy. In this study, we examined the paracrine factors released by human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) and their ability to accelerate the wound-healing process by stimulating proliferation and migration of dermal fibroblasts. AF-MSCs expressed the typical MSC marker proteins CD13, CD29, and CD44 and differentiated into adipocytes, osteoblasts, and chondrocytes when exposed to the appropriate differentiation media. In addition, AF-MSC-conditioned media (AF-MSC-CM) significantly enhanced proliferation of dermal fibroblasts. Antibody-based protein array and enzyme-linked immunosorbent assay (ELISA) indicated that AF-MSC-CM contains various cytokines and chemokines that are known to be important in normal wound healing, including IL-8, IL-6, TGF-β, TNFRI, VEGF, and EGF. Application of AF-MSC-CM significantly enhanced wound healing by dermal fibroblasts via the TGF-β/SMAD2 pathway. Levels of p-SMAD2 were increased by AF-MSC-CM, and both the increase in p-SMAD2 and migration of dermal fibroblasts were blocked by inhibiting the TGF-β/SMAD2 pathway. Moreover, in a mouse excisional wound model, AF-MSC-CM accelerated wound healing. These data provide the first evidence of the potential for AF-MSC-CM in the treatment of skin wounds. © Copyright 2010, Mary Ann Liebert, Inc.

Kim S.-Y.,Catholic University of Korea | Park Y.-J.,Catholic University of Korea | Johnson J.R.,University of Minnesota | Yu J.K.,Catholic University of Korea | And 2 more authors.
Diagnostic Microbiology and Infectious Disease | Year: 2016

We investigated the prevalence and characteristics of Escherichia coli sequence type 131 (ST131) and its subclones among 268 E. coli isolates. The isolates were collected from 21 Korean hospitals without use of selection criteria and were screened for ST131 status by PCR. ST131 isolates were characterized for extended-spectrum β-lactamase variants, fluoroquinolone resistance genes, plasmid addiction systems, and replicon types. The collection's 57 identified ST131 isolates (21% of 268) were distributed disproportionately by clonal subset, as follows: 21 (37%) H30Rx, 27 (47%) H30 non-Rx, and 8 (14%) non- H30. Most (93%) ST131 isolates were ciprofloxacin resistant, and all H30 isolates had the same 5 nonsynonymous mutations in gyrA, parC, and parE. Twenty (95%) of H30Rx isolates harbored CTX-M-15, whereas only 14 (52%) of H30 non-Rx isolates harbored CTX-M-14 or CTX-M-27. Most (97%) ST131 isolates harbored IncF plasmids, but vagCD was confined exclusively to H30Rx. Our findings suggest that the distinctive characteristics of H30Rx isolates could have contributed to this subclone's recent epidemiologic success. © 2016 Elsevier Inc.

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