• Polymer(Korea)
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• v.30 no.6
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• pp.464-470
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• 2006

Diblock copolymers consisting of methoxy Poly (ethylene glycol) (MPEG) and poly (${\epsilon}-ca$ prolactone) (PCL), poly(${\delta}-valerolactone$) (PVL), poly(L-lactide) (PLLA), or poly(L-lactide-co-glycolide) (PLGA) were prepared to compare the characterization of diblock copolymers as a drug carrier. MPEG-PCL, MPEG-PVL, MPEG-PLLA, and MPEG-PLGA diblock copolymers were synthesized by the ring-opening polymerization of ${\epsilon}$-caprolactone or ${\delta}$-valerolactone in the presence of $HCl{\cdot}Et_2O$ as a monomer activator at room temperature and by the ring-opening polymerization of L-lactide or a mixture of L-lactide and glycolide in the presence of stannous octoate at $130^{\circ}C$, respectively. The synthesized diblock copolymers were characterized with $^1H-NMR$, GPC, DSC, and XRD. The micellar characterization of MPEG-polyester diblock copolymers in an aqueous phase was carried out by using NMR, dynamic light scattering, AFM, and fluorescence techniques. Most micelles exhibited a spherical shape in AFM. Thus, ore confirmed that the micelles formed with MPEG-polyester diblock copolymers have possibility as a potential hydrophobic drug delivery vehicle because a hydrophobic drug could be preferentially distributed in the micelle core.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1127-1135
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• 2009

Purpose : To observe the abnormal white matter findings on the magnetic resonance imaging (MRI) scans of very-low- birth-weight (VLBW) infant brains at term-equivalent age and to determine the clinical risk factors for the development of periventricular leukomalacia (PVL). Methods : In all, MRI was performed in 98 VLBW infants and the white matter abnormalities were observed. Clinical risk factors for cystic and noncystic PVL were determined. Results : MRI scans of 74 infants (75.5%) showed diffuse excessive high signal intensity (DEHSI) in the periventricular white matter, 17 (17.3%) lateral ventricle dilation, 5 (5.1%) and 11 (11.2%) focal punctate lesions and cystic changes in the periventricular white matter, respectively, 9 (9.1%), germinal layer hemorrhage (GLH) or subependymal cysts 3 (3.1%) intraventricular hemorrhage (>grade 2) 2 (2.0%) posthemorrhagic hydrocephalus and 2 (2.0%) periventricular hemorrhagic infarct. Gestational age (GA), 1-minute Apgar score, Clinical Risk Index for Babies-II (CRIB-II) score, and inotrope use, and GA, CRIB-II score, postnatal steroid administration, inotrope use, and abnormal white blood cell (WBC) count at admission were related to cystic PVL and noncystic PVL development, respectively (P<0.05). However, in logistic regression analysis, CRIB-II (odds ratio, 1.63, 295% confidence interval, 1.15-2.30 P=0.006) for cystic PVL, and GA (odds ratio 0.90, 95% confidence interval, 0.82-0.99 P=0.036) for noncystic PVL were only significant independently. Conclusion : White matter abnormalities could be observed on MRI scans of the VLBW infant brains at term-equivalent age, and CRIB-II and GA were only independently significant for cystic and noncystic PVL development, respectively.

• Neonatal Medicine
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• v.17 no.1
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• pp.64-74
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• 2010

Purpose : The aim of this study was to determine the risk factors, clinical characteristics and prognosis for the development of periventricular leukomalacia (PVL) in preterm infants according to the extent and site of the PVL. Methods : The medical records of infants (under 36 weeks of gestational age) delivered from January 1999 to December 2008 were reviewed. Twenty-five preterm infants with were PVL were diagnosed by brain magnetic resonance imaging (MRI) and an addition 50preterm infants with no brain lesions were enrolled in this study. The perinatal and neonatal risk factors for the development of PVL was determine in these infants. Mental and Psychomotor Developmental Indices (MDI, PDI) were assessed by a clinical psychologist using the Bayley Scales of Infant Development II. We compared the differences of the clinical characteristics and prognosis according to brain MRI findings. Results : Maternal fever, young maternal age, extended oxygen use, hypotension within the first week of birth, use of inotropics within the first week of birth, and respiratory distress syndrome were the risk factors associated with PVL (P <0.05). In the multivariate analysis, maternal fever and extended oxygen use were statistically significant independent risk factors (P <0.05). The mean MDI and PDI scores of the PVL group (74.4$\pm$ 27.8 and 58.0$\pm$17.7) were significantly lower than those of the control group (103.5$\pm$8.9 and 101.7$\pm$16.1, P <0.05). Conclusion : Maternal fever and extended oxygen use were independent risk factors for PVL. We should pay attention to infants who had the risk factors and follow them up closely by brain imaging study and Bayley Scales of Infant Development II.

• Pediatric Infection and Vaccine
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• v.25 no.2
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• pp.107-112
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• 2018

Staphylococcus aureus is now a major community-acquired pathogen worldwide, notably associated with skin and soft tissue infections. Staphylococci are present in the form of colonizers or environmental contaminants at home and increase the risk of recurrent infection. We are describing recurrent familial furunculosis caused by Panton-Valentine Leukocidin-positive methicillin susceptible S. aureus ST1 in Korea. An infant, his father and mother had furunculosis due to methicillin-sensitive S. aureus (MSSA) infection with identical susceptibility patterns. ST1 accounted for all 3 isolates and they were confirmed of having agr group I. Both sec and seh were detected in all isolates using polymerase chain reaction (PCR) assays, and all isolates contained Panton-Valentine leukocidin (PVL) genes. Risk factors for the household spread of S. aureus include skin conditions and close physical contact among household members. The relationship between S. aureus colonization of household contacts and the occurrence of S. aureus infection should be studied into more detail.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.202-209
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• 2016

This study is aimed to determine the correlation between the toxin gene types and antibiotic resistance from MRSA (methicillin-resistant Staphylococcus aureus). Fifty-two strains of MRSA, between January 2014, and December 2014, were isolated from clinical specimens obtained from 2,664 cases in the intensive care unit of a hospital in Suncheon, Jeonnam, Korea. Genes encoding mecA, enterotoxin (SE), toxic shock syndrome toxin-1 (TSST-1), exfoliative toxin (ET), and Panton-Valentine leukocidin (PVL) were detected by multiplex PCR-mediated amplification using specific primers. Toxin genes (seg and sei) were present in 40 strains (76.9%), followed by tst in 34 strains (65.4%). Other genes (eta, etb, sea, sed, see, seh, sej, and pvl) were not detected. Forty strains (76.9%) of MRSA had 2 or more toxin genes simultaneously; 5 coexistent toxin-genes (seb, sec, seg, sei, tst) were the most common in 28 strains (53.8%), and 6 strains (11.5%) had seg and sei genes. The coexistence of genes were 72.5~100%, showing a high correlation among genes (seb, sec, seg, sei and tst). As strains (seb, sec, tst) that had particular toxin genes (seb, sec, seg, sei, tst) in multiple showed 100% resistance to ciprofloxacin, clindamycin, erythromycin, we were able to find that seb, sec, and tst genes have a close relationship to the aforementioned antibiotics. It showed a higher resistance to ciprofloxacin, clindamycin, erythromycin, and tetracycline compared with strains that had toxin genes independent from multiple toxin genes.

• Journal of Life Science
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• v.21 no.2
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• pp.257-264
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• 2011

Seventy five methicillin- resistant Staphylococcus aureus (MRSA) strains and 24 methicillin- susceptible S. aureus (MSSA) were isolated from clinical specimens obtained from a hospital in Suncheon, Jeonnam province, Korea, from July to December, 2009. Antibiotic resistance was determined using the disc diffusion method. Genes encoding enterotoxin (SE), toxic shock syndrome toxin-1 (TSST-1), exfoliative toxin (ET) and Panton-Valentine leukocidin (PVL) were detected by multiplex PCR-mediated amplification using specific primers. Sixty (80%) MRSA isolates possessed either one or more toxin genes and the most common pattern that coexisted in MRSA was seb, sec, seg, sei and tst (22.7%) followed by coexistence of sec, seg, sei and tst genes (18.7%). Gene pvl encoding leukocidin was not found. Significant correlation between the production of sec, seg, sei and tst genes was found. MRSAs were resistant to erythromycin (89% of the isolates), gentamicin (70.7%), ciprofloxacin (69.3%), clindamycin (61.3%) and tetracycline (58.7%), while MSSAs were susceptible to the antibiotics with the exception of erythromycin. Toxin genes seb, sec and tst were related to the tetracycline resistance of MRSA.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.3
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• pp.274-282
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• 2002

This paper discusses a multi-dimensional analysis for Customer Relationship Management (CRM). For this, We propose a decision-making methodology which employs three analysis models. The first model is a three-dimension positioning map to derive a strategy which achieves the Process Value Line (PVL). The second model is the web-shape analysis model to visibly understand the individual based on the customer CSI (Customer Satisfactory Index) data. The third model which supports the web-shape analysis model, is the relative satisfactory analysis model. It considers a satisfaction level after purchasing against before purchasing. Then we perform overall analysis based on the three analysis models to provide marketing strategies to decision makers.

• Clinical and Experimental Pediatrics
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• v.50 no.11
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• pp.1067-1071
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• 2007

Purpose : The aim of this study was to determine whether improved survival of extremely low birth weight infants (ELBWI) was associated with decreased neurodevelopmental disability later in life, and also to identify the factors influencing this disability. Methods : ELBWI admitted to the neonatal intensive care unit of Samsung Medical Center, survived, and followed up until the corrected age of 18 months were enrolled. They were divided into two groups according to admission time: period I (1994-1999, n=36) and period II (2000-2004, n=98). Clinical data were collected retrospectively from the medical records. Results : Survival rates increased from 60.0% to 74.7%, cerebral palsy rates decreased from 22.2% to 8.2% and catch-up growth rate increased from 25.0% to 51.0% during period I and II. Despite less gestational age and birth weight, ELBWI during period II had less periventricular leukomalacia (PVL), sepsis and bronchopulmonary dysplasia compared to period I. The highest risk factors for cerebral palsy were intraventricular hemorrhage (IVH) (${\geq}$Grade III), failure of catch-up growth and PVL. Conclusion : In summary, improved viability was associated with decreased neurodevelopmental disability in ELBWI. Improved neonatal care with resultant decrease in PVL and IVH, and better nutritional support seem to be primarily responsible for this improved outcome.

• Pediatric Infection and Vaccine
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• v.23 no.1
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• pp.62-66
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• 2016

Skin and soft tissue infections (SSTIs) caused by community-associated (CA)-methicillin-resistant Staphylococcus aureus (MRSA) have become a worldwide concern. An otherwise healthy 16-month-old Korean girl was admitted because of skin abscess on the left chest wall with a history of recurrent SSTIs since the age of 6 months. Immunologic evaluation including serum immunoglobulin level and nitroblue-tetrazolium (NBT) test were normal. Pus and nasal swab cultures revealed CA-MRSA ST714-SCCmec type IV with the Panton-Valentine leukocidin (PVL) genes, which was initially reported in the Netherlands in 2006 and has not been previously reported in Korea. The skin abscesses were successfully treated by needle aspiration and the use of antibiotics. In addition, nasal mupirocin was applied as a decolonization method. No more episodes of SSTI were observed over a follow-up period of 10 months.

• Tuberculosis and Respiratory Diseases
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• v.75 no.2
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• pp.75-78
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• 2013

Methcillin-resistant Staphylococcus aureus (MRSA) has emerged as an important cause of community-acquired infections, which has been recently designated as community-associated (CA) MRSA. Panton-Valentine leukocidin (PVL)-negative multilocus sequence type 72 (ST72)-staphylococcal cassette chromosome mec (SCCmec) type IV has been reported as the predominat CA-MRSA strain in Korea and is commonly associated with skin and soft tissue infections in addition to healthcare-associated pneumonia. However, community-acquired pneumonia (CAP) for this strain has not yet been reported. We hereby report two cases of CAP caused by PVL-negative ST72-SCCmec type IV strain in patients who had no risk factors for MRSA acquisition. While CA-MRSA infections are not yet prevalent in Korea, our cases suggest that CA-MRSA should be considered in cases of severe CAP, especially for cases associated with necrotizing pneumonia.