Publications by authors named "Young-Soo Cho"

10 Publications

  • Page 1 of 1

Electrical Cartridge Sensor Enables Reliable and Direct Identification of MicroRNAs in Urine of Patients.

ACS Sens 2021 03 7;6(3):833-841. Epub 2020 Dec 7.

Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.

Urinary miRNAs are biomarkers that demonstrate considerable promise for the noninvasive diagnosis and prognosis of diseases. However, because of background noise resulting from complex physiological features of urine, instability of miRNAs, and their low concentration, accurate monitoring of miRNAs in urine is challenging. To address these limitations, we developed a urine-based disposable and switchable electrical sensor that enables reliable and direct identification of miRNAs in patient urine. The proposed sensing platform combining disposable sensor chips composed of a reduced graphene oxide nanosheet and peptide nucleic acid facilitates the label-free detection of urinary miRNAs with high specificity and sensitivity. Using real-time detection of miRNAs in patient urine without pretreatment or signal amplification, this sensor allows rapid, direct detection of target miRNAs in a broad dynamic range with a detection limit down to 10 fM in human urine specimens within 20 min and enables simultaneous quantification of multiple miRNAs. As confirmed using a blind comparison with the results of pathological examination of patients with prostate cancer, the sensor offers the potential to improve the accuracy of early diagnosis before a biopsy is taken. This study holds the usefulness of the practical sensor for the clinical diagnosis of urological diseases.
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http://dx.doi.org/10.1021/acssensors.0c01870DOI Listing
March 2021

Manganese-Doped Tin Oxide for Highly Flexible and Transparent Multilayer Electrodes with Index-Matching Layers.

J Nanosci Nanotechnol 2020 Jan;20(1):594-598

Department of Information Display, Hongik University, Seoul, 121-791, South Korea.

We fabricated transparent Mn (2.59 wt.%)-doped tin oxide (MTO)/Ag/MTO films with refractive index-matching layers (IMLs) on a polyethylene terephthalate (PET) substrate. To reduce refractive index-mismatching, polydimethylsiloxane (PDMS) and MTO layers were inserted between the MTO/Ag/MTO multilayer film and the PET substrate. MTO and Ag were deposited by RF/DC magnetron sputtering at room temperature, whereas spin-coating was used to deposit PDMS at various dilution ratios in hexane. In this study, pattern visibility was examined by comparing the differences in the color and reflectance of oxide/metal/oxide multilayers before and after adding the PDMS and MTO IMLs. In addition, the effects of the PDMS dilution ratio on the electrical and optical characteristics were also investigated. The MTO/Ag/MTO/PDMS/MTO multilayer films showed high transmittance (>86% at 550 nm) except at the dilution ratio of 1:50. As the PDMS dilution ratio increased from 1:50 to 1:200, the reflectance difference (Δ) increased from 0.08% to 0.35% and the color difference (Δ*) increased from 0.31 to 1.23. The maximum resistance changes of the multilayer films were 0.126% and 0.124% after outer and inner bending, respectively, for 10,000 cycles with a radius of curvature of 4 mm.
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http://dx.doi.org/10.1166/jnn.2020.17255DOI Listing
January 2020

Oxygen Concentration Dependence of the Optical and Electrical Properties of Mn-Doped Tin Oxide Thin Films Deposited on a Polyethylene Terephthalate Substrate.

J Nanosci Nanotechnol 2020 Jan;20(1):505-509

Department of Materials Engineering, Chungbuk National University, Cheongju 28644, Korea.

Mn (2.59 wt.%)-doped tin oxide (MTO) was deposited on a polyethylene terephthalate (PET) substrate using RF magnetron sputtering at room temperature. Oxygen was introduced during the sputtering process to prevent the reduction of transmittance and the formation of nonstoichiometric compositions. The dependence of the optical and electrical properties of MTO thin films on the O₂/(Ar+O₂) ratio was systematically investigated. The transmittance of the MTO single layer (24 nm) at 550 nm gradually increased from 85.9% to 88.2% with an increase of the O₂/(Ar+O₂) ratio from 0% to 7.9%. The optical band gap was also affected by the O₂/(Ar+O₂) ratio, varying from 3.30 to 3.64 eV. The MTO film deposited at an O₂/(Ar+O₂) ratio of 2.7% showed the minimum resistivity (0.03 Ω·cm). The XPS spectra indicated that the SnO₂ thin films become almost stoichiometric as the O₂/(Ar+O₂) ratio increased. Thus, this sputtering process can be used to prepare flexible MTO films with a wider optical band gap, improved transmittance, and decreased resistivity.
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http://dx.doi.org/10.1166/jnn.2020.17254DOI Listing
January 2020

A Rho-Associated Coiled-Coil Containing Kinase Inhibitor, Y-27632, Improves Viability of Dissociated Single Cells, Efficiency of Colony Formation, and Cryopreservation in Porcine Pluripotent Stem Cells.

Cell Reprogram 2019 02 8;21(1):37-50. Epub 2019 Jan 8.

1 Department of Animal Bioscience, College of Agriculture and Life Sciences, Gyeongsang National University, Jinju, Republic of Korea.

The establishment of porcine epiblast stem cells (pEpiSCs) and induced pluripotent stem cells (piPSCs) derived from diametrical derivations is of great importance in developing biomedical models. However, pEpiSCs and piPSCs have been technically much harder to culture than mouse embryonic stem cells, showing problematic properties such as spontaneous differentiation and apoptosis after cryopreservation. Therefore, we demonstrated that Y-27632 as a Rho-associated coiled-coil containing kinase inhibitor could prevent dissociated pEpiSCs and piPSCs from undesirable differentiation and apoptosis in cryopreservation protocols. pEpiSC 2, 8 lines, Sendai virus-induced pluripotent stem cells (Sev-iPSCs), and lentivirus-induced pluripotent stem cells were cultured with 10 μM Y-27632 before collecting dissociated cells retrieved from colonies using various enzymes. Dissociated single cells were transferred into freezing mediums (open pulled straw vitrification, STEM-CELLBANKER (SCB), 10% dimethylsulfoxide in serum) for cryopreservation. The rates of viability and colony formation obtained from dissociated porcine stem cells after freezing/thawing were examined in the presence of Y-27632. The characteristics of pluripotency and in vitro differentiation were also examined in these stem cells treated with Y-27632 after cryopreservation. As a result, the viability and efficiency of colony formation of dissociated pEpiSCs (2, 8 lines) and Sev-iPSCs treated with 10 μM Y-27632 using the SCB cryopreservation protocol were significantly increased when compared with those of nontreated Y-27632 (p < 0.05). Pluripotency genes (OCT-3/4, NANOG, and SOX2) were positively expressed in Y-27632-treated porcine pluripotent stem cells. Also, in vitro differentiation of these stem cells was successfully induced in the presence of 10 μM Y-27632. These results indicated that treatment of Y-27632 for single-cell dissociation and the SCB cryopreservation protocol could facilitate handling porcine pluripotent stem cells and provide the widespread use of these stem cells.
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http://dx.doi.org/10.1089/cell.2018.0020DOI Listing
February 2019

Clinical and Laboratory Findings of Middle East Respiratory Syndrome Coronavirus Infection.

Jpn J Infect Dis 2019 May 25;72(3):160-167. Epub 2018 Dec 25.

Department of Preventive Medicine, Korea University College of Medicine.

There is a paucity of data regarding the differentiating characteristics of patients with laboratory-confirmed and those negative for Middle East respiratory syndrome coronavirus (MERS-CoV) in South Korea. This hospital-based retrospective study compared MERS-CoV-positive and MERS-CoV-negative patients. A total of seven positive patients and 55 negative patients with a median age of 43 years (P = 0.845) were included. No statistical differences were observed with respect to their sex and the presence of comorbidities. At the time of admission, headache (28.6% vs. 3.6%; odds ratio [OR], 10.60; 95% confidence interval [CI], 1.22-92.27), myalgia (57.1% vs. 9.1%; OR, 13.33; 95% CI, 2.30-77.24), and diarrhea (57.1% vs. 14.5%; OR, 7.83; 95% CI, 1.47-41.79) were common among MERS-CoV-positive patients. MERS-CoV-positive patients were more likely to have a low platelet count (164 ± 76.57 vs. 240 ± 79.87) and eosinophil (0.27 ± 0.43 vs. 2.13 ± 2.01; P = 0.003). Chest radiography with diffuse bronchopneumonia was more frequent in MERS-CoV-positive patients than in negative patients (100% vs. 62.5%; P = 0.491). The symptoms of headache, myalgia, and diarrhea, as well as laboratory characteristics, including low platelet counts and eosinophil, and chest X-ray showing diffuse bronchopneumonia might enhance the ability to detect patients in South Korea infected with MERS-CoV.
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http://dx.doi.org/10.7883/yoken.JJID.2018.187DOI Listing
May 2019

[Missionary Medicine of Canadian Presbytery and Korean Doctors under Japanese Occupation--focusing Sung-jin and Ham-heung].

Uisahak 2015 Dec;24(3):621-57

Baeksang Dental Clinic, Seoul, Korea.

In East Asia during the second half of the 19th century, overseas mission work by Protestant churches thrived. Missionaries built schools and hospitals and effectively used them for evangelism. In the 20th century when Social Gospel Movement was expanding, medical work has been recognized as a significant mission service in and by itself. This article reviewed the construction and characteristics of missions work conducted by Canadian Presbytery; missionary doctors and Korean doctors who worked at the mission hospitals; why the missionary medical work had to stop; and career paths taken by Korean doctors upon liberation from Japanese occupation. The Canadian Presbytery missionaries, unlike other denomination missionaries, were rather critical of Imperial Japan, but supportive towards Koreans. This could have stemmed from the reflection of their own experience of once a colony of British Empire and also their value system that promotes egalitarian, democratic and progressive theology. The Sung-jin and Ham-heung Mission Bases were a community, interacting organically as a 'Triangle of Church, School and Hospital.' The missionaries mobilized the graduates from Christian schools and organized a Young Men's Christian Association (YMCA). Some of the graduates were trained to become medical doctors or assistants and worked at mission hospitals. Missionary doctors' approaches to balancing evangelism and medical practice varied. For example, Robert Grieson went through confusion and struggled to balance conflicting roles as a pastor for evangelism and also as a physician. Kate McMillan, on the other hand, had less burden for evangelism than Grieson, and focused on medical work by taking advantage of the opportunity that, as a woman, she can easily approach Korean women. Still another case was Florence Murray who practised evangelism within the hospital setting, and successfully carried out the role as a hospital administrator, going beyond 'women's work' as McMillan did. Korean doctors and assistants who worked at the mission hospitals had seen the spread of Protestantism in their youth; had received modern education; had experienced the fall of own country in 1910 and nationwide protest against Japan in 1919. The majority of them were graduates of Severance Medical College, the hub of missionary medicine at the time. After the resignation from the mission hospitals, 80 percent of them became self-employed general practitioners. The operations of the mission hospitals began to contract in 1930 due to tightened control by Imperial Japan. Shrine worship imposed on Christians caused internal conflict and division among missionaries and brought about changes in the form and contents of the mission organization. The incidence of the assault of Dr. Grieson brought about the dissolution of Sung-jin mission base and the interruption of the operation of Je-dong Hospital. As the Pacific War expanded, missionaries were driven out of Korea and returned home. In conclusion, the missions work by Canadian Presbytery missionaries had greatly impacted Protestantism in Korea. The characteristics of Canadian Presbytery were manifested in their support of Korean nationalism movement, openness for Social Gospel, and maintaining equal footing with Korean Christians. Specifically we note the influence of these characteristics in Chosun doctors who had worked in the mission hospitals. They operated their own hospitals or clinics in a manner similar to the mission hospitals by providing treatment for poor patients free of charge or for a nominal fee and treating the patients in a kind and humanistic way. After the 1945 Liberation, Korean doctors'career paths split into two directions. most of them defected to South Korea and chose the path to work as general practitioners. A few of them remained in North Korea and became educator of new doctors. It is meaningful that former doctors of Canadian missionary hosptal became dean of 2 medical colleges among 3 of all in early North Korea. This article does not cover the comparative analysis of the medical work by the missionaries of Canadian Presbytery and other denominations. It is desirable to include this analysis of the contents and the comparison in a future study of Korean doctors who participated in the mission hospitals, by denomination and by geographical region.
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http://dx.doi.org/10.13081/kjmh.2015.24.621DOI Listing
December 2015

[Formation of medical education in North Korea: 1945-1948].

Uisahak 2014 Aug;23(2):239-68

Baeksang Dental Clinic, Seoul, KOREA.

This study focuses on the formation of medical education in North Korea from 1945 to 1948 in terms of the centralization of medical education, and on the process and significance of the systemization of medical education. Doctors of the past trained under the Japanese colonial system lived and worked as liberalists. More than half of these doctors who were in North Korea defected to South Korea after the country was liberated. Thus the North Korean regime faced the urgent task of cultivating new doctors who would 'serve the state and people.' Since the autumn of 1945, right after national liberation, Local People's Committees organized and implemented medical education autonomously. Following the establishment of the Provisional People's Committee of North Korea, democratic reform was launched, leading to the centralized administration of education. Consequently, medical educational institutions were realigned, with some elevated to medical colleges and others shut down. The North Korean state criticised the liberalistic attitude of doctors and the bureaucratic style of health administration, and tried to reform their political consciousness through political inculcation programs. The state also grant doctors living and housing privileges, which show its endeavor to build 'state medicine'. By 1947, a medical education system was established in which the education administration was put in charge of training new doctors while the health administration was put in charge of nurturing and retraining health workers. In this way, the state was the principal agent that actively established a centralized administrative system in the process of the formation of medical education in North Korea following national liberation. Another agent was deeply involved in this process - the faculty that was directly in charge of educating the new doctors. Studying the medical faculty remains another research task for the future. By exploring how the knowledge, generational experience, socio-political consciousness and world views adopted by these teachers during the colonial era were manifested in their pedagogy after national liberation will shed more light on the 'prototype' of North Korean medical education.
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http://dx.doi.org/10.13081/kjmh.2014.23.239DOI Listing
August 2014

Active pulmonary tuberculosis and latent tuberculosis infection among homeless people in Seoul, South Korea: a cross-sectional study.

BMC Public Health 2013 Aug 5;13:720. Epub 2013 Aug 5.

Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University College of Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea.

Background: The aim of this study was to determine the prevalence rate of latent TB infection (LTBI) and active TB among homeless in Seoul metropolitan city, South Korea, and to compare the TB burden among homeless people with that of a control group.

Methods: The homeless participants were recruited from five sites between October 30, 2009 and April 12, 2010. LTBI was diagnosed through the QuantiFERON(R) TB Gold In-Tube(QFT-GIT) assay and a tuberculin skin test(TST) and, and active PTB was diagnosed based on chest radiography.

Results: Among 313 participants, the prevalence of LTBI was 75.9% (95% CI, 71.1-80.8%) and 79.8% (95% CI, 74.9-84.7%) based on a QFT-GIT assay and the TST, respectively, and that of active PTB was 5.8% (95% CI, 3.2-8.3%). The prevalence of LTBI among homeless participants was about five times higher than controls. Also, the age-specific prevalence rate ratio of active PTB was as high as 24.86.

Conclusions: The prevalence rate of LTBI as well as active PTB among homeless people was much higher than that of the general population in South Korea. Thus, adequate strategies to reduce the TB burden among homeless people are needed.
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http://dx.doi.org/10.1186/1471-2458-13-720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3750398PMC
August 2013

Treatment outcome and mortality among patients with multidrug-resistant tuberculosis in tuberculosis hospitals of the public sector.

J Korean Med Sci 2011 Jan 22;26(1):33-41. Epub 2010 Dec 22.

Clinical Research Center, National Masan Tuberculosis Hospital, Masan, Korea.

This study was conducted to evaluate treatment outcome, mortality, and predictors of both in patients with multidrug-resistant tuberculosis (MDR-TB) at 3 TB referral hospitals in the public sector of Korea. We included MDR-TB patients treated at 3 TB referral hospitals in 2004 and reviewed retrospectively their medical records and mortality data. Of 202 MDR-TB patients, 75 (37.1%) had treatment success and 127 (62.9%) poor outcomes. Default rate was high (37.1%, 75/202), comprising 59.1% of poor outcomes. Male sex (adjusted odds ratio [aOR], 2.91; 95% confidence interval [CI], 1.13-7.49), positive smear at treatment initiation (aOR, 5.50; 95% CI, 1.22-24.90), and extensively drug-resistant TB (aOR, 10.72; 95% CI, 1.23-93.64) were independent predictors of poor outcome. The all-cause mortality rate was 31.2% (63/202) during the 3-4 yr after treatment initiation. In conclusion, the treatment outcomes of patients with MDR-TB at the 3 TB hospitals are poor, which may reflect the current status of MDR-TB in the public sector of Korea. A more comprehensive program against MDR-TB needs to be integrated into the National Tuberculosis Program of Korea.
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http://dx.doi.org/10.3346/jkms.2011.26.1.33DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3012847PMC
January 2011

A comparative evaluation of different compensating curves in the lingual and labial techniques using 3D FEM.

Am J Orthod Dentofacial Orthop 2003 Apr;123(4):441-50

Department of Dentistry, University of Ulsan, Seoul.

Because adults dislike the visibility of orthodontic appliances, the use of the lingual orthodontic technique has increased over time. But few studies compare tooth movement of the lingual technique with that of the labial technique. In this study, human mandibular left teeth were aligned, and a 3-dimensional finite element model was made (consisting of 19382 nodes and 12150 elements). To compare the effect of compensating curves on canine retraction between the lingual and the labial orthodontic techniques, the compensating curve was increased on the.016-in stainless steel labial or lingual archwire, and a 150-g force was applied distally on the canine. The relative direction and the amount of tooth displacement of the finite element model were compared on a schematic displacement graph (magnified 10,000 times), and the compressive stress distributed on the root surface was observed. The pattern of tooth movement (with or without a compensating curve) was different between the labial and the lingual techniques. As the amount of compensating curve increased (0, 2, and 4 mm) in the archwire, the rotation and the distal tipping of the canine was reduced. The antitip and antirotation action of compensating curve on the canine retraction was greater in the labial archwire than in the lingual archwire.
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http://dx.doi.org/10.1067/mod.2003.9DOI Listing
April 2003