• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1377-1383
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• 2006

Among 46 Acinetobacter baumannii isolates collected in 2004, two imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Republic of Korea. Two carbapenemase-producing isolates were further investigated to determine the mechanism of resistance. These isolates were analyzed by antibiotic susceptibility testing, microbiological tests of carbapenemase activity, determination of pI, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. Two cases of infection by A. baumannii producing the IMP-1 ${\beta}$-lactamase were detected. The isolates were characterized by a modified cloverleaf synergy test and EDTA-disk synergy test. Isoelectric focusing of crude bacterial extracts revealed nitrocefin-positive bands with a pI value of 9.0. PCR amplification and characterization of the amplicons by direct sequencing indicated that the isolates carried a $bla_{IMP-l}$ determinant. The isolates were characterized by a multidrug resistance phenotype, including penicillins, extended-spectrum cephalosporins, carbapenems, and aminoglycosides. These results indicate that the observed imipenem resistance of two Korean A. baumannii isolates was due to the spread of an IMP-1-producing clone. Our microbiological test of carbapenemase activity is simple to screen class B metallo-${\beta}$-lactamase-producing clinical isolates to determine their clinical impact and to prevent further spread. This study shows that the $bla_{IMP-l}$ resistance determinant, which is emerging in Korea, may become an emerging therapeutic problem, since clinicians are advised not to use extended-spectrum cephalosporins, imipenem, and aminoglycosides. This observation emphasizes the importance of having effective control measures in Asian hospitals, such as early detection of colonized patients, isolation procedures, and a judicious use of antibiotics.

• IMMUNE NETWORK
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• 제23권4호
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• pp.35.1-35.16
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• 2023

Defining the molecular dynamics associated with T cell differentiation enhances our understanding of T cell biology and opens up new possibilities for clinical implications. In this study, we investigated the dynamics of CD5 expression in CD8⁺ T cell differentiation and explored its potential clinical uses. Using PBMCs from 29 healthy donors, we observed a stepwise decrease in CD5 expression as CD8⁺ T cells progressed through the differentiation stages. Interestingly, we found that CD5 expression was initially upregulated in response to T cell receptor stimulation, but diminished as the cells underwent proliferation, potentially explaining the differentiation-associated CD5 downregulation. Based on the proliferation-dependent downregulation of CD5, we hypothesized that relative CD5 expression could serve as a marker to distinguish the heterogeneous CD8⁺ T cell population based on their proliferation history. In support of this, we demonstrated that effector memory CD8⁺ T cells with higher CD5 expression exhibited phenotypic and functional characteristics resembling less differentiated cells compared to those with lower CD5 expression. Furthermore, in the retrospective analysis of PBMCs from 30 non-small cell lung cancer patients, we found that patients with higher CD5 expression in effector memory T cells displayed CD8⁺ T cells with a phenotype closer to the less differentiated cells, leading to favorable clinical outcomes in response to immune checkpoint inhibitor (ICI) therapy. These findings highlight the dynamics of CD5 expression as an indicator of CD8⁺ T cell differentiation status, and have implications for the development of predictive biomarker for ICI therapy.

• IMMUNE NETWORK
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• 제22권5호
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• pp.40.1-40.24
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• 2022

Mesenchymal stem cells (MSCs) are attractive alternatives to conventional anti-asthmatic drugs for severe asthma. Mechanisms underlying the anti-asthmatic effects of MSCs have not yet been elucidated. This study evaluated the anti-asthmatic effects of intravenously administered MSCs, focusing on macrophages and monocytes. Seven-week-old transgenic (Tg) mice with lung-specific overexpression of IL-13 were used to simulate chronic asthma. MSCs were intravenously administered four days before sampling. We examined changes in immune cell subpopulations, gene expression, and histological phenotypes. IL-13 Tg mice exhibited diverse features of chronic asthma, including severe type 2 inflammation, airway fibrosis, and mucus metaplasia. Intravenous administration of MSCs attenuated these asthmatic features just four days after a single treatment. MSC treatment significantly reduced SiglecF^-CD11c^-CD11b⁺ monocyte-derived macrophages (MoMs) and inhibited the polarization of MoMs into M2 macrophages, especially M2a and M2c. Furthermore, MSCs downregulated the excessive accumulation of Ly6c^- monocytes in the lungs. While an intravenous adoptive transfer of Ly6c^- monocytes promoted the infiltration of MoM and Th2 inflammation, that of MSC-exposed Ly6c^- monocytes did not. Ex vivo Ly6c^- MoMs upregulated M2-related genes, which were reduced by MSC treatment. Molecules secreted by Ly6c^- MoMs from IL-13 Tg mice lungs upregulated the expression of fibrosis-related genes in fibroblasts, which were also suppressed by MSC treatment. In conclusion, intravenously administered MSCs attenuate asthma phenotypes of chronic asthma by modulating macrophages. Identifying M2 macrophage subtypes revealed that exposure to MSCs transforms the phenotype and function of macrophages. We suggest that Ly6c^- monocytes could be a therapeutic target for asthma management.

• Molecules and Cells
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• 제38권9호
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• pp.781-788
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• 2015

Mutations of MYO15A are generally known to cause severe to profound hearing loss throughout all frequencies. Here, we found two novel MYO15A mutations, c.3871C>T (p.L1291F) and c.5835T>G (p.Y1945X) in an affected individual carrying congenital profound sensorineural hearing loss (SNHL) through targeted resequencing of 134 known deafness genes. The variant, p.L1291F and p.Y1945X, resided in the myosin motor and IQ2 domains, respectively. The p.L1291F variant was predicted to affect the structure of the actin-binding site from three-dimensional protein modeling, thereby interfering with the correct interaction between actin and myosin. From the literature analysis, mutations in the N-terminal domain were more frequently associated with residual hearing at low frequencies than mutations in the other regions of this gene. Therefore we suggest a hypothetical genotype-phenotype correlation whereby MYO15A mutations that affect domains other than the N-terminal domain, lead to profound SNHL throughout all frequencies and mutations that affect the N-terminal domain, result in residual hearing at low frequencies. This genotype-phenotype correlation suggests that preservation of residual hearing during auditory rehabilitation like cochlear implantation should be intended for those who carry mutations in the N-terminal domain and that individuals with mutations elsewhere in MYO15A require early cochlear implantation to timely initiate speech development.

• 한국임상수의학회지
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• 제27권2호
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• pp.147-153
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• 2010

연골밑뼈와 연골이식편 사이의 생유합성은 임상적으로 중요한 과제이다. 현재까지 탈회골기질의 이용은 생체내 뼈세포 증식에 있어서 가장 효과적인 방법이다. 본 연구에서는 연골세포와 탈회골기질의 공배양을 통해 뼈와 연골의 유도 목적에 부합되는 모든 필수적인 요소를 갖는 재료로 이용가능 여부를 확인하고자 실시되었다. 본 연구의 목적은 두 종류의 배양법 즉, 펠렛 배양과 알긴산 배양에서 탈회골기질과 공배양된 소 연골세포의 증식과 표현형을 비교, 평가하는 것이다. 알긴산 배양에서는 세포 군집의 형성 및 연골세포의 수적 증가가 관찰되었다. 전형적인 연골세포의 표현형이 시험기간인 8주에 걸쳐 유지되었으며, 조직학적인 검사에서 연골세포는 일반적인 원형의 형태를 유지하였고, 연골세포방과 연골세포가 점진적으로 증가하였다. 대조군(연골세포 단독배양)에 비해 탈회골기질과 공배양한 두군 모두에서 많은 세포증식이 관찰되었으며, 글리코사미노글리칸의 생성 또한 증가되었다.

• BMB Reports
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• 제56권10호
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• pp.569-574
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• 2023

Aberrant DNA methylation plays a pivotal role in the onset and progression of colorectal cancer (CRC), a disease with high incidence and mortality rates in Korea. Several CRC-associated diagnostic and prognostic methylation markers have been identified; however, due to a lack of comprehensive clinical and methylome data, these markers have not been validated in the Korean population. Therefore, in this study, we aimed to obtain the CRC methylation profile using 172 tumors and 128 adjacent normal colon tissues of Korean patients with CRC. Based on the comparative methylome analysis, we found that hypermethylated positions in the tumor were predominantly concentrated in CpG islands and promoter regions, whereas hypomethylated positions were largely found in the open-sea region, notably distant from the CpG islands. In addition, we stratified patients by applying the CpG island methylator phenotype (CIMP) to the tumor methylome data. This stratification validated previous clinicopathological implications, as tumors with high CIMP signatures were significantly correlated with the proximal colon, higher prevalence of microsatellite instability status, and MLH1 promoter methylation. In conclusion, our extensive methylome analysis and the accompanying dataset offers valuable insights into the utilization of CRC-associated methylation markers in Korean patients, potentially improving CRC diagnosis and prognosis. Furthermore, this study serves as a solid foundation for further investigations into personalized and ethnicity-specific CRC treatments.

• 대한한방내과학회지
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• 제36권4호
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• pp.547-561
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• 2015

Objectives In this study, we divided Korean asthma patients into excess syndrome or deficiency syndrome groups according to clinical phenotype. Genetic analysis was conducted to investigate the association of exonic SNPs in the CD46 gene polymorphism with the clinical phenotype based on the differentiation syndrome of the bronchial asthma patients.Methods There were 95 healthy patients (control group) and 53 asthma patients. (The deficiency syndrome group included 24 and the excess syndrome group 29). We searched the exonic areas of the CD46 gene in the NCBI website SNPs with <0.01 minor allele frequency (MAF) and <0.01 heterozygosity. We finally selected two SNPs: rs138843816, Ser13Phe and rs7144, 3’-UTR. Hardy-Weinberg equilibrium was calculated using SNPStats.Results There were significant differences in the codominant 1 model and the dominant model between the healthy group and the asthma group. There were significant differences between deficiency syndrome group and the excess syndrome group in the genotype frequencies and in the codominant 1 model, the dominant model, and the log-additive model. The allele frequency of rs7144C showed a significant difference between the deficiency syndrome group and the excess syndrome group. Two-SNP haplotype analysis showed a significant difference in frequency in the deficiency syndrome group and in the excess syndrome group. There were significant differences between the healthy group and the excess syndrome group in the codominant 1 model, the dominant model, and the log-additive model. The frequency of the rs7144 C allele exhibited a significant difference in the demonstration. SNP haplotype analysis between the healthy group and the excess syndrome group showed a significant difference in the frequency of the CT haplotype and the CC haplotype.Conclusions The results indicate that two CD46 SNPs (rs138843816, Ser13Phe and rs7144, 3′–UTR) might be associated with the symptomatic excess syndrome in Korean asthma patients.

• Clinical and Experimental Pediatrics
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• 제55권11호
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• pp.438-444
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• 2012

Mucolipidosis II (ML II) or inclusion cell disease (I-cell disease) is a rarely occurring autosomal recessive lysosomal enzyme-targeting disease. This disease is usually found to occur in individuals aged between 6 and 12 months, with a clinical phenotype resembling that of Hurler syndrome and radiological findings resembling those of dysostosis multiplex. However, we encountered a rare case of an infant with ML II who presented with prenatal skeletal dysplasia and typical clinical features of severe secondary hyperparathyroidism at birth. A female infant was born at $37^{+1}$ weeks of gestation with a birth weight of 1,690 g (<3rd percentile). Prenatal ultrasonographic findings revealed intrauterine growth retardation and skeletal dysplasia. At birth, the patient had characteristic features of ML II, and skeletal radiographs revealed dysostosis multiplex, similar to rickets. In addition, the patient had high levels of alkaline phosphatase and parathyroid hormone, consistent with severe secondary neonatal hyperparathyroidism. The activities of ${\beta}$-D-hexosaminidase and ${\alpha}$-N-acetylglucosaminidase were moderately decreased in the leukocytes but were 5- to 10-fold higher in the plasma. Examination of a placental biopsy specimen showed foamy vacuolar changes in trophoblasts and syncytiotrophoblasts. The diagnosis of ML II was confirmed via GNPTAB genetic testing, which revealed compound heterozygosity of c.3091C>T (p.Arg1031X) and c.3456_3459dupCAAC (p.Ile1154GlnfsX3), the latter being a novel mutation. The infant was treated with vitamin D supplements but expired because of asphyxia at the age of 2 months.

• Journal of Microbiology
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• 제44권4호
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• pp.423-431
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• 2006

Among 53 Acinetobacter baumannii isolates collected in 2004, nine imipenem-resistant isolates were obtained from clinical specimens taken from patients hospitalized in Busan, Korea. Nine carbapenemase-producing isolates were further investigated in order to determine the mechanisms underlying resistance. These isolates were then analyzed via antibiotic susceptibility testing, microbiological tests of carbapenemase activity, pI determination, transconjugation test, enterobacterial repetitive consensus (ERIC)-PCR, and DNA sequencing. One outbreak involved seven cases of infection by A. baumannii producing OXA-23 ${\beta}-lactamase$, and was found to have been caused by a single ERIC-PCR clone. During the study period, the other outbreak involved two cases of infection by A. baumannii producing IMP-1 ${\beta}-lactamase$. The two clones, one from each of the outbreaks, were characterized via a modified cloverleaf synergy test and an EDTA-disk synergy test. The isoelectric focusing of the crude bacterial extracts detected nitrocefin-positive bands with pI values of 6.65 (OXA-23) and 9.0 (IMP-1). The PCR amplification and characterization of the amplicons via direct sequencing showed that the clonal isolates harbored $bla_{IMP-1}$ or $bla_{oxA-23}$ determinants. The two clones were characterized by a multidrug resistance phenotype that remained unaltered throughout the outbreak. This resistance encompassed penicillins, extended-spectrum cephalosporins, carbapenems, monobactams, and aminoglycosides. These results appear to show that the imipenem resistance observed among nine Korean A. baumannii isolates could be attributed to the spread of an IMP-lor OXA-23-producing clone. Our microbiological test of carbapenemase activity is a simple method for the screening of clinical isolates producing class D carbapenemase and/or class B $metallo-{\beta}-lactamase$, in order both to determine their clinical impact and to prevent further spread.

• Tuberculosis and Respiratory Diseases
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• 제72권4호
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• pp.367-373
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• 2012

Background: Chronic obstructive pulmonary disease (COPD) is now regarded as a heterogenous disease, with variable phenotypes. Acute exacerbation of COPD is a major event that alters the natural course of disease. The frequency of COPD exacerbation is variable among patients. We analyzed clinical features, according to the frequency of acute exacerbation in COPD. Methods: Sixty patients, who visited Gyeongsang National University Hospital from March 2010 to October 2010, were enrolled. Patients were divided into two groups, according to their frequency of acute exacerbation. Frequent exacerbator is defined as the patient who has two or more exacerbation per one year. We reviewed patients' medical records and investigated modified Medical Research Council (MMRC) dyspnea scale, smoking history and frequency of acute exacerbation. We also conducted pulmonary function test and 6-minute walking test, calculated body mass index, degree of airway obstruction and dyspnea and exercise capacity (BODE) index and measured CD146 cells in the peripheral blood. Results: The number of frequent exacerbators and infrequent exacerbators was 20 and 40, respectively. The frequent exacerbator group had more severe airway obstruction (forced expiratory volume in one second [$FEV_1$], 45% vs. 65.3%, p=0.001; $FEV_1$/forced vital capacity, 44.3% vs. 50.5%, p=0.046). MMRC dyspnea scale and BODE index were significantly higher in the frequent exacerbator group (1.8 vs. 1.1, p=0.016; 3.9 vs. 2.1, p=0.014, respectively). The fraction of CD146 cells significantly increased in the frequent exacerbator group (2.0 vs. 1.0, p<0.001). Conclusion: Frequent exacerbator had more severe airway obstruction and higher symptom score and BODE index. However, circulating endothelial cells measured by CD146 needed to be confirmed in the future.