• Journal of Life Science
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• v.26 no.9
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• pp.1056-1062
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• 2016

Lung cancer is currently the most common malignant disease and the leading cause of mortality in the world and non-small cell lung cancer (NSCLC) accounts for 75-80% of lung cancer cases. miR-155 gene was found to be over expressed in several solid tumors, such as thyroid carcinoma, breast cancer, colon cancer, cervical cancer, pancreatic ductal adenocarcinoma (PDAC) and lung cancer. The aims of this study were to define the expression of miR-155 in lung cancer and its associated clinic-pathologic characteristics. Total RNA was purified from formalin-fixed, paraffin-embedded NSCLC tissues and benign lung tissues. Expression of miR-155 in human lung cancer tissues were evaluated as mean fold changes of miR-155 in cancer tissues compared to benign lung tissues by quantitative real-time reverse transcriptase polymerase chain reaction (real-time qRT-PCR) and associations of miR-155 expression with clinic-pathologic findings of cancer. Compared with the benign control group, miR-155 expression was significantly overexpressed in NSCLCs (p=<0.001). miR-155 was more overexpressed in squamous cell carcinoma than in adenocarcinoma. Poorly differentiated tumors showed significantly overexpression of miR-155 than well-differentiated tumors (p=<0.001). Overexpression of miR-155 was significantly associated with lymph node metastasis (p=<0.05). In survival analysis for all NSCLC patients, high miR-155 expression was significantly correlated with worse overall survival (p=<0.05). These results suggested that miR-155 might play an important role in lung cancer progression and metastasis.

• Journal of Genetic Medicine
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• v.8 no.1
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• pp.1-16
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• 2011

Owing to the risk of fetal loss associated with prenatal diagnostic procedures (amniocentesis, chorionic villus sampling), noninvasive prenatal diagnosis (NIPD) is ultimate goal of prenatal diagnosis. The discovery of circulating cell-free fetal DNA (cffDNA) in maternal plasma in 1997 has opened up new probabilities for NIPD by Dr. Lo et al. The last decade has seen great development in NIPD. Fetal sex and fetal RhD status determination by cffDNA analysis is already in clinical use in certain countries. For routine use, this test is limited by the amount of cell-free maternal DNA in blood sample, the lack of universal fetal markers, and appropriate reference materials. To improve the accuracy of detection of fetal specific sequences in maternal plasma, internal positive controls to confirm to presence of fetal DNA should be analyzed. We have developed strategies for noninvasive determination of fetal gender, and fetal RhD genotyping using cffDNA in maternal plasma, using real-time quantitative polymerase chain reaction (RT-PCR) including RASSF1A epigenetic fetal DNA marker (gender-independent) as internal positive controls, which is to be first successful study of this kind in Korea. In our study, accurate detection of fetal gender through gestational age, and fetal RhD genotyping in RhD-negative pregnant women was achieved. In this assay, we show that the assay is sensitive, easy, fast, and reliable. These developments improve the reliability of the applications of circulating fetal DNA when used in clinical practice to manage sex-linked disorders (e.g., hemophilia, Duchenne muscular dystrophy), congenital adrenal hyperplasia (CAH), RhD incompatibility, and the other noninvasive pregnant diagnostic tests on the coming soon. The study was the first successful case in Korea using cffDNA in maternal plasma, which has created a new avenue for clinical applications of NIPD.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.95-100
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• 2007

The cellulase gene of Bacillus licheniformis K11 which has plant growth-promoting activity by auxin and antagonistic ability by siderophore was cloned in pUC18 using PCR employing heterologous primers. The 1.6kb PCR fragment contained the full sequence of the cellulase gene, denoted celW which has been reported to encode a 499 amino acid protein. Similarity search in protein data base revealed that the cellulase from B. licheniformis K11 was more than 97% identical in amino acid sequence to those of various Bacillus spp. The cellulase protein from B. licheniformis K11, overproduced in E. coli DH5${\alpha}$ by the lac promoter on the vector, had apparent molecular weight of 55 kDa upon CMC-SDS-PAGE analysis. The protein not only had enzymatic activity toward carboxymethyl-cellulose (CMC), but also was able to degrade insoluble cellulose, such as Avicel and filter paper (Whatman$^{\circledR}$ No. 1). In addition, the cellulase could degrade a fungal cell wall of Phytophthora capsici. Consequently B. licheniformis K11 was able to suppress the peperblight causing P. capsici by its cellulase. Biochemical analysis showed that the enzyme had a maximum activity at 60$^{\circ}C$ and pH 6.0. Also, the enzyme activity was activated by Co$^{2+}$ of Mn$^{2+}$ but inhibited by Fe$^{3+}$ or Hg$^{2+}$. Moreover, enzyme activity was not inhibited by SDS or sodium azide.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.8
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• pp.979-984
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• 2006

Although iron is essential for many physiological processes, excess iron can lead to tissue damage by promoting the generation of reactive oxygen species (ROS). There is increasing evidence that ROS might play an important role in the pathogenesis of cardiovascular disease. However, the effects of iron excess on platelet function and the thrombotic response to vascular injury are not well understood. We examined the effects of iron excess-induced oxidative stress and the antioxidants on platelet aggregation. Oxidative stress was accessed by either free iron $(Fe^{+2})$ or hydrogen peroxide $(H_2O_2)$, as well as their combination on washed rabbit platelets (WPs) in vitro. When WPs were stimulated with either $Fe^{+2}$ alone or a subthreshold concentration of collagen, which gave an aggregatory curve with a little effect, and a dose dependent increase in platelet aggregation was observed by increasing concentrations of $Fe^{+2}$ with $H_2O_2$. This aggregation was associated with the iron-catalyzed formation of hydroxyl radicals from $H_2O_2$, and were inhibited by NAD/NADP (proton acceptor), catalase $(H_2O_2\;scavenger)$, tiron (iron chelator), mannitol (hydroxyl radical scavenger), and indomethacin (cyclooxygenase inhibitor), but not by NADH/NADPH (proton donor), superoxide mutase, and aspirin. However, NADH/NADPH, an essential cofactor for the antioxidant capacity by the supply of reducing potentials, showed the effect of an enhanced radical formation, suggesting a role for NADH/NADPH-dependent oxidase. These results suggest that iron $(Fe^{+2})$ can directly interact with washed rabbit platelets and this aggregation be mediated by OH formation as in the Fenton reaction, inhibited by radical scavengers.

• Journal of Gastric Cancer
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• v.7 no.1
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• pp.9-15
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• 2007

Purpose: DNA methylation is an important epigenetic factor in tumorigenesis. We hypothesized that polymorphism of the promoter of the DNA methyltransferase 3b (DNMT3b) genes, which are responsible for regulating the methylation status of tumor suppressor genes, are associated with increased risk of gastric cancer. Materials and Methods: In this hospital-based case-control study, to determine the role of this polymorphism of the promoter of DNA methyltransferase 3b (DNMT3b) genes in gastric cancer, we genotyped 176 cases and 70 control subjects. To determine the genotype, we used a polymerase chain reaction restriction fragment length polymorphism assay. We compared alleles and genotypes between the two groups and revealed an association of DNMT3b promoter polymorphism with increased risk of gastric cancer in the Korean population. Results: Genotype frequencies were 14.8% (Cytosine-Cytosine), 71.6% (Cytosine-Thymine), and 13.6% (Thymine- Thymine) in the case patients and 40.0% (Cytosine-Cytosine), 42.9% (Cytosine-Thymine), and 17.1% (Thymine-Thymine) in the control subjects, respectively. Compared with CC homozygotes, CT heterozygotes had a 4.523-fold increased risk (OR, 2.13; 95% CI, 2.324~8.803), and the TT homozygotes had a 2.154-fold elevated risk (OR, 1.42; 95% CI, 0.899~85.165). For the T variant genotype (CT+TT), there was a 3.846-fold increased risk (OR, 1.88; 95% CI, 2.040~7.251). However, no significance was observed in the genotype distributions of both polymorphisms according to histopathology, stage of stomach cancer. The Ssame results were observed with Helicobacter infection. Conclusion: DNMT3b promoter polymorphism, especially the T variant genotype, is associated significantly with thean increased risk of gastric cancer.

• Tuberculosis and Respiratory Diseases
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• v.45 no.6
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• pp.1178-1187
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• 1998

Background : Recently the incidence of tuberculosis is increasing in many countries and control of the disease is further threatened by the emergence of multi-drug resistant tuberculosis. So rapid detection of drug resistance is very important. Pyrazinamide (PZA) is a first-line chemotherapeutic agent for tuberculosis. Now in Korea, we perform PZase activity test instead of actual pyrazinamide susceptibility test for the detection of PZA resistant M. tuberculosis. Recently the pncA gene, encoding the PZase of M. tuberculosis, was completely sequenced. And it was reported that the mutation of pncA gene would be associated with PZA resistance of M. tuberculosis. Therefore we performed this study to evaluate the possibility for the rapid detection of PZA resistant M. tuberculosis using PCR-SSCP of pncA gene. Method : 44 cultured clinical isolates of M. tuberculosis, BCG Tokyo strain. BCG French strain, and one M. bovis isolate were studied. We used H37Rv as the reference strain, The PZase activity test was done at the reference laboratory of Korean Tuberculosis Institute. DNA was extracted by bead-beater method and 561 bp fragment including pncA gene was amplified by PCR. The PCR product were digested by BstB I enzyme. SSCP was done using MDE gel. Of the 44 strains of M. tuberculosis, 22 strains were PZase-positive and other 22 strains were PZase negative. Results : Of the 22 PZase positive strains, 18 strains(82%) showed the same mobility compared with that of H37Rv and 4(18%) showed different mobility. Of the 22 PZase-negative strains, 19(86%) strains showed the same mobility pattern compared with that of H37Rv and 3(14%) showed different mobility. Naturally PZA-resistant BeG-French strain, BCG-Tokyo strain, and one M. bovis isolate showed the same band pattern each other, but their mobility were different from that of H37Rv. The results of PZase activity test and PCR-SSCP of pncA of M. tuberculosis were statistically significantly correlated each other (p<0.01). Conclusion : The PCR-SSCP after BstB I restriction of pncA gene of M. tuberculosis may be a useful method for the rapid detection of PZA-resistant M. tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.47 no.4
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• pp.471-477
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• 1999

Background : Smoking and high-risk occupation have been known to be the risk factors of lung cancer. The carcinogen-metabolizing enzymes in human body such as glutathione S-transferase M1, T1 and N-acetyltransferase 1 have also been regarded as risk factors in many cancers, because the activities of those enzymes play a role in metabolizing the carcinogen. A case-control study was conducted to evaluate the genetic polymorphism of GSTM1, T1 and NAT1 in lung carcinogenesis in Korean men. Methods : The histologically proven lung cancer cases were recruited from Seoul National University Hospital. The patients of more than 40-year-old with the nonmalignant urinary tract diseases were recruited as controls from the same hospitals. The informations of demographical characteristics and smoking were obtained by interview or chart review and the genetic polymorphisms of GSTM1, T1 and NAT1 were determined by PCR-based assay. The statistical analyses were performed by linear logistic regression. Results : The number of case-control was 118 and 150, respectively. The smoking history was significantly higher in the lung cancer patients than the controls. The prevalence of GSTM1 null-type was statistically higher(OR=2.25 ; 95% CI=1.12-4.51) in squamous cell carcinoma than other genotypes, but other histologic types were not The prevalence of GSTT1 null-type were not statistically higher than other genotypes in all histologic types. The fast acetylator of NAT1 was more prevalent than normal(OR=2.13 ; 95% CI=1.04-4.40) in all lung cancer patients. Conclusion : The null-type of GSTM1 and fast acetylator of NAT1 are associated with development of lung cancer in Korean men.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.797-806
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• 1999

Background: About 20% of small cell lung cancer(SCLC) patients have bone marrow(EM) metastasis at the time of diagnosis and the remaining patients are also considered with micrometastasis. In an attempt to detect EM micrometastasis, we used cytokeratin(CK)-20 as a molecular marker, which is specific for epithelial cells. Method: A sensitive RT-PCR assay was used to compare CK-20 expression both in SCLC cell line H209 and normal leukocyte and to evaluate EM aspirates of 28 SCLC patients. Result: H209 cell line showed CK-20 expression but normal leukocyte did not, suggesting CK-20 expression is lung tissue-specific. Of 28 patients(11 limited disease, 17 extensive disease), only 2(1/11, 1/17) samples tested revealed positive signal for CK-20. Two patients with CK-20 expression had EM metastasis or multiple bone involvement during follow-up. Conclusion: Although circulating tumor cells were detected in EM of small portion of patients with bone metastasis, CK-20 doesn't seem to be a reliable marker for the detection of micrometastasis in SCLC. This study emphasizes that identification of more specific marker for micrometastsis is mandatory prior to clinical application.

• Tuberculosis and Respiratory Diseases
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• v.57 no.1
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• pp.37-46
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• 2004

Background : Lung pericytes are important constituent cells of blood-air barrier in pulmonary microvasculature. These cells take part in the control of vascular contractility and permeability. In this study, it was hypothesized that change of lung pericytes might be attributable to pathologic change in microvasculature in acute lung injury. The purpose of this study was how hypoxia change proliferation and genetic expression in lung pericytes. Methods : From the lungs of several Sprague-Dawley rats, performed the primary culture of lung pericytes and subculture. Characteristics of lung pericytes were confirmed with stellate shape in light microscopy and immunocytochemistry. 2% concentration of oxygen and $200{\mu}M$ $CoCl_2$ were treated to cells. Tryphan blue method and reverse transcription-polymerase chain reaction were done. Results : 1. We established methodology for primary culture of lung pericytes. 2. Hypoxia inhibited cellular proliferation in pericytes. 3. Hypoxia could markedly induce vascular endothelial growth factor(VEGF) and smad-2. 4. Hypoxia-inducible factor-$1{\alpha}$(HIF-$1{\alpha}$) was also induced by 2% oxygen. Conclusion : Viability of lung pericytes are inhibited by hypoxia. Hypoxia can stimulate expression of hypoxia-responsive genes. Pericytic change may be contributed to dysfunction of alveolar-capillary barrier in various pulmonary disorders.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1977.06a
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• pp.4.4-5
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• 1977

The vibratory energy introduced into the external ear canal is changed by the mechanical factors of eardrum itself, the motility of ossicles, and the air cushion of tympanic cavity and the like. This study was designed to investigate the volume of middle ear cavity and mastoid air cell system as a factor of determining the accoustic impedance of middle ear system. The author studied how the increase in air volume of middle ear cavity effects on the acoustic impedance of middle ear system with dogs' ears and researched the correlation between the degree of pneumatization of temporal bones and the acoustic impedance of middle ear system by comparing the radiological findings of pneumatization (Law's and Towne's projection) with the acoustic impedance measurements with Madsen ZO 70. The result is as follows: 1 The tympanometric findings in control state revealed the curves of type A, and did not change in its configuration by the increase in the air volume of dogs middle ear system. 2. The static compliance of middle ear revealed a distinct and linear increase in proportion to the increase in air volume of middle ear system; the rate of increase was $0.05{\pm}0.02$ cc of static compliance per cc of air volume. 3. Authenticated in the above result and the tendency to increase in static compliance in proportion to the increase in the degree of pneumatization of temporal bones, there was significant regression equation between the degree of pneumatization of temporal bones (x variable) and the static compliance of middle ear system; $y=0.19x{\pm}0.16{\pm}0.05$ It is suggested that the difference in volume of middle ear system plays an important role in the change of the static compliance of middle ear, and the author concludes that the measurement of static compliance of middle ear has clinical value as diagnostic means of evaluating the degree of pneumatization of temporal bones along with some radiological examination.