1.Identification of Retroviral Vectors Producing High Viral Titer.
Yong Jae SHIN ; Michael J LENARDO ; Tae Kyu PARK ; Kwang Ho LEE
Journal of the Korean Society of Virology 1999;29(1):33-38
Retroviral vector provide a highly efficient method for gene transfer into eukaryotic cells. This vector system can be divided into two components; the retroviral vector itself and the retroviral packaging cell line. The key improvement in the design of these two components are. focused on two aspects; the reduction of helper virus production and high titer-virus. We used PA317 for retrovirus packaging cell line, for its high producibility of viral titer, To test the ability of the vectors to generate high titer-virus, we have chosen four different retroviral vectors; LN, LNSX, LNCX and LXSN. To test easily the viral titer, we have made recombinant construction with CD4 and CD8, checked their viral titer and stained their surface expression. LXSN which contain SV40 early promoter in front of leo gene showed best results in viral transient transfection assay, dot blot assay and surface expression. In addition, recombinant containing CD8 generally showed much higher viral titration and surface expression than CD4.
Cell Line
;
Eukaryotic Cells
;
Helper Viruses
;
Product Packaging
;
Retroviridae
;
Transfection
;
Zidovudine*
2.Patient Dose Management: Focus on Practical Actions.
Michael Yong PARK ; Seung Eun JUNG
Journal of Korean Medical Science 2016;31(Suppl 1):S45-S54
Medical radiation is a very important part of modern medicine, and should be only used when needed and optimized. Justification and optimization of radiation examinations must be performed. The first step of reduction of medical exposure is to know the radiation dose in currently performed examinations. This review covers radiation units, how various imaging modalities report dose, and the current status of radiation dose reports and legislation. Also, practical tips that can be applied to clinical practice are introduced. Afterwards, the importance of radiology exposure related education is emphasized and the current status of education for medical personal and the public is explained, and appropriate education strategies are suggested. Commonly asked radiation dose related example questions and answers are provided in detail to allow medical personnel to answer patients. Lastly, we talk about computerized programs that can be used in medical facilities for managing patient dose. While patient dose monitoring and management should be used to decrease and optimize overall radiation dose, it should not be used to assess individual cancer risk. One must always remember that medically justified examinations should always be performed, and unneeded examinations should be avoided in the first place.
Humans
;
*Radiation Dosage
;
Radiation Protection
;
Radiation, Ionizing
;
Tomography, X-Ray Computed
3.CT radiation dose and radiation reduction strategies.
Michael Yong PARK ; Seung Eun JUNG
Journal of the Korean Medical Association 2011;54(12):1262-1268
There has been a recent increase in attention focused on the potential risk of radiation-induced carcinogenesis from diagnostic radiology, with a particular emphasis on computed tomography (CT). After the rapid adoption of multidetector CT (MDCT), radiation doses from CT are now the single largest source of diagnostic radiation exposure to patients, and the carcinogenesis risk from diagnostic CT radiation dose exposure can no longer be ignored by physicians. To understand the exposure risk and monitor radiation dose exposure, an understanding and interest in CT dose reports is necessary. Almost all MDCTs now show and allow storage of the volume CT dose index (CTDIvol), dose length product (DLP), and effective dose estimations on dose reports, which are essential to assess patient radiation exposure and risks. To decrease these radiation exposure risks, the principles of justification and optimization should be followed. Justification means that the examination must be medically indicated and useful. Optimization means that the imaging should be performed using doses that are as low as reasonably achievable (ALARA), consistent with the diagnostic task. Optimization includes understanding and changing CT protocols to perform the same diagnostic task with the minimal amount of radiation exposure while maintaining diagnostic accuracy. Physicians and radiologists must be aware of the radiation risks associated with CT exams, and understand and implement the principles for patient radiation dose reduction.
Adoption
;
Cone-Beam Computed Tomography
;
Humans
;
Organothiophosphorus Compounds
4.Performance of Humphrey Matrix Frequency Doubling Technology Perimetry and Standard Automated Perimetry Global Indices.
Yoonpyo NAM ; Sung Yong KANG ; Seong Bae PARK ; Kyung Rim SUNG ; Michael S KOOK
Journal of the Korean Ophthalmological Society 2009;50(11):1680-1685
PURPOSE: To evaluate and compare the diagnostic performance of Humphrey Matrix frequency doubling technology perimetry (Matrix) global indices with standard automated perimetry (SAP) for glaucoma discrimination. METHODS: Forty-seven healthy and 63 glaucomatous subjects were included in this study. Glaucoma was defined as having glaucomatous optic disc and glaucomatous visual field defect. Correlations of mean deviation (MD) and pattern standard deviation (PSD) between Matrix and SAP were evaluated. Areas under receiver operating characteristic curves (AUCs) for discriminating healthy from glaucoma, sensitivity, and cut-off value at fixed specificity of MD and PSD were determined in Matrix and SAP. RESULTS: MD and PSD from Matrix were highly correlated with SAP data in glaucomatous eyes (r=0.80, 0.69 p<0.001, <0.001). The AUCs of MD and PSD from Matrix (0.941, 0.921) were of comparable diagnostic capability to SAP data (0.876, 0.923, p=0.068, 0.927). The sensitivity at 90% specificity of MD was 67.9% in SAP, 76.4% in Matrix, with the cut off value of MD at 90% specificity at -3.10dB in SAP and -3.72dB in Matrix. CONCLUSIONS: MD and PSD data from Matrix and SAP significantly correlated in glaucomatous eyes and showed similar diagnostic performance for discriminating healthy from glaucoma however, both MD and PSD are scaled differently on SAP and Matrix, which suggests that application of these parameters in a manner similar to that used in SAP should be employed with caution.
Area Under Curve
;
Eye
;
Glaucoma
;
ROC Curve
;
Sensitivity and Specificity
;
Visual Field Tests
;
Visual Fields
5.Preliminary Experience Using Dynamic MRI at 3.0 Tesla for Evaluation of Soft Tissue Tumors.
Michael Yong PARK ; Won Hee JEE ; Sun Ki KIM ; So Yeon LEE ; Joon Yong JUNG
Korean Journal of Radiology 2013;14(1):102-109
OBJECTIVE: We aimed to evaluate the use of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) at 3.0 T for differentiating the benign from malignant soft tissue tumors. Also we aimed to assess whether the shorter length of DCE-MRI protocols are adequate, and to evaluate the effect of temporal resolution. MATERIALS AND METHODS: Dynamic contrast-enhanced magnetic resonance imaging, at 3.0 T with a 1 second temporal resolution in 13 patients with pathologically confirmed soft tissue tumors, was analyzed. Visual assessment of time-signal curves, subtraction images, maximal relative enhancement at the first (maximal peak enhancement [Emax]/1) and second (Emax/2) minutes, Emax, steepest slope calculated by using various time intervals (5, 30, 60 seconds), and the start of dynamic enhancement were analyzed. RESULTS: The 13 tumors were comprised of seven benign and six malignant soft tissue neoplasms. Washout on time-signal curves was seen on three (50%) malignant tumors and one (14%) benign one. The most discriminating DCE-MRI parameter was the steepest slope calculated, by using at 5-second intervals, followed by Emax/1 and Emax/2. All of the steepest slope values occurred within 2 minutes of the dynamic study. Start of dynamic enhancement did not show a significant difference, but no malignant tumor rendered a value greater than 14 seconds. CONCLUSION: The steepest slope and early relative enhancement have the potential for differentiating benign from malignant soft tissue tumors. Short-length rather than long-length DCE-MRI protocol may be adequate for our purpose. The steepest slope parameters require a short temporal resolution, while maximal peak enhancement parameter may be more optimal for a longer temporal resolution.
Adult
;
Aged
;
Aged, 80 and over
;
Contrast Media/diagnostic use
;
Diagnosis, Differential
;
Female
;
Gadolinium DTPA/diagnostic use
;
Humans
;
Image Interpretation, Computer-Assisted/methods
;
Magnetic Resonance Imaging/*methods
;
Male
;
Middle Aged
;
Soft Tissue Neoplasms/*pathology
;
Statistics, Nonparametric
;
Subtraction Technique
6.Benign Lymphoproliferative Disorder of the Perirenal Space and Renal Sinus in Sjogren's Syndrome: A Case Report.
Yu Ri SHIN ; Seung Eun JUNG ; Michael Yong PARK ; Kook Jin AHN ; Jae Mun LEE ; Gyeongsin PARK
Journal of the Korean Radiological Society 2008;58(3):303-306
We report a case of benign lymphoproliferative disease involving the perirenal space and renal sinus in patients with Sjogren's syndrome, which simulated malignant lymphoma. CT scans revealed homogeneous soft tissue masses in both renal sinuses and perirenal thin band-like lesions. An ultrasonogrphy revealed thin hypoechoic rims along the capsule of both kidneys as well as hypoechoic masses filled in renal sinuses. The lesions completely regressed following steroid treatment. Although rare, since these benign lymphoproliferative disorders with a similar appearance to lymphoma can occur in patients with Sjogren's syndrome, pathological biopsies should be performed.
Biopsy
;
Humans
;
Kidney
;
Lymphoma
;
Lymphoproliferative Disorders
;
Sjogren's Syndrome
;
Tomography, Spiral Computed
7.Enhanced Strategies through National Tri-temporal Analysis of Public Capacity Prepared for Laypersons' Cardiopulmonary Resuscitation.
Yeong Ki LEE ; Tae Ho NHO ; Yong Seok PARK ; Mi Jin LEE ; Sung Oh HWANG ; Kyoung Chul CHA ; Gyu Chong CHO ; You Dong SOHN ; Michael Sung Pil CHOE
Journal of the Korean Society of Emergency Medicine 2016;27(6):549-555
PURPOSE: Bystander cardiopulmonary resuscitation (CPR) and dissemination of its training are essential to improve the survival outcomes of sudden cardiac death. The purpose of this study was to investigate the tri-temporal trend analysis of the national CPR capacity variables and preparedness in a community. METHODS: This nationwide population-based study used structured questionnaire by a telephone survey for CPR in 2007 (n=1,029), in 2011 (n=1,000), and in 2015 (n=1,000). We used stratified cluster sampling to assess the impact of age, gender, and geographic regions. The contents in the questionnaire consisted of CPR awareness, self-efficacy for bystander CPR, prior training status, and willingness of public CPR training. RESULTS: The proportion of CPR awareness and its recent training experience (<2 years) increased from 89.0% and 14.6%, respectively, in 2007 to 88.5% and 18.7% in 2011, and finally to 94.8% and 30.6% in 2015 (both p for trend<0.001). More than 95% of respondents had agreed to mandatory CPR training acquiring a driver's license or CPR education in school. The awareness of Good Samaritan Law was increased from 20.5% in 2011 to 28.7% in 2015; however, the overall values were lower than the other CPR-related awareness and preparedness. CONCLUSION: In Korea, the trends of national CPR capacity index have been increasing during the past decade. However, the public awareness of the Good Samaritan Law was still low. We suggest that promoting the Good Samaritan Law should be the next step in preparing public CPR training in the future.
Cardiopulmonary Resuscitation*
;
Death, Sudden, Cardiac
;
Education
;
Health Services Needs and Demand
;
Humans
;
Jurisprudence
;
Korea
;
Licensure
;
Surveys and Questionnaires
;
Telephone
8.Proinflammatory Cytokine and Nitric Oxide Production by Human Macrophages Stimulated with Trichomonas vaginalis.
Ik Hwan HAN ; Sung Young GOO ; Soon Jung PARK ; Se Jin HWANG ; Yong Seok KIM ; Michael Sungwoo YANG ; Myoung Hee AHN ; Jae Sook RYU
The Korean Journal of Parasitology 2009;47(3):205-212
Trichomonas vaginalis commonly causes vaginitis and perhaps cervicitis in women and urethritis in men and women. Macrophages are important immune cells in response to T. vaginalis infection. In this study, we investigated whether human macrophages could be involved in inflammation induced by T. vaginalis. Human monocyte-derived macrophages (HMDM) were co-cultured with T. vaginalis. Live, opsonized-live trichomonads, and T. vaginalis lysates increased proinflammatory cytokines, such as TNF-alpha, IL-1beta, and IL-6 by HMDM. The involvement of nuclear factor (NF)-kappaB signaling pathway in cytokine production induced by T. vaginalis was confirmed by phosphorylation and nuclear translocation of p65 NF-kappaB. In addition, stimulation with live T. vaginalis induced marked augmentation of nitric oxide (NO) production and expression of inducible NO synthase (iNOS) levels in HMDM. However, trichomonad-induced NF-kappaB activation and TNF-alpha production in macrophages were significantly inhibited by inhibition of iNOS levels with L-NMMA (NO synthase inhibitor). Moreover, pretreatment with NF-kappaB inhibitors (PDTC or Bay11-7082) caused human macrophages to produce less TNF-alpha. These results suggest that T. vaginalis stimulates human macrophages to produce proinflammatory cytokines, such as IL-1, IL-6, and TNF-alpha, and NO. In particular, we showed that T. vaginalis induced TNF-alpha production in macrophages through NO-dependent activation of NF-kappaB, which might be closely involved in inflammation caused by T. vaginalis.
Animals
;
Cells, Cultured
;
Cytokines/*immunology
;
Humans
;
Macrophages/*immunology/parasitology
;
Nitric Oxide/*immunology
;
Trichomonas Infections/*immunology/parasitology
;
Trichomonas vaginalis/*immunology
9.Proinflammatory Cytokine and Nitric Oxide Production by Human Macrophages Stimulated with Trichomonas vaginalis.
Ik Hwan HAN ; Sung Young GOO ; Soon Jung PARK ; Se Jin HWANG ; Yong Seok KIM ; Michael Sungwoo YANG ; Myoung Hee AHN ; Jae Sook RYU
The Korean Journal of Parasitology 2009;47(3):205-212
Trichomonas vaginalis commonly causes vaginitis and perhaps cervicitis in women and urethritis in men and women. Macrophages are important immune cells in response to T. vaginalis infection. In this study, we investigated whether human macrophages could be involved in inflammation induced by T. vaginalis. Human monocyte-derived macrophages (HMDM) were co-cultured with T. vaginalis. Live, opsonized-live trichomonads, and T. vaginalis lysates increased proinflammatory cytokines, such as TNF-alpha, IL-1beta, and IL-6 by HMDM. The involvement of nuclear factor (NF)-kappaB signaling pathway in cytokine production induced by T. vaginalis was confirmed by phosphorylation and nuclear translocation of p65 NF-kappaB. In addition, stimulation with live T. vaginalis induced marked augmentation of nitric oxide (NO) production and expression of inducible NO synthase (iNOS) levels in HMDM. However, trichomonad-induced NF-kappaB activation and TNF-alpha production in macrophages were significantly inhibited by inhibition of iNOS levels with L-NMMA (NO synthase inhibitor). Moreover, pretreatment with NF-kappaB inhibitors (PDTC or Bay11-7082) caused human macrophages to produce less TNF-alpha. These results suggest that T. vaginalis stimulates human macrophages to produce proinflammatory cytokines, such as IL-1, IL-6, and TNF-alpha, and NO. In particular, we showed that T. vaginalis induced TNF-alpha production in macrophages through NO-dependent activation of NF-kappaB, which might be closely involved in inflammation caused by T. vaginalis.
Animals
;
Cells, Cultured
;
Cytokines/*immunology
;
Humans
;
Macrophages/*immunology/parasitology
;
Nitric Oxide/*immunology
;
Trichomonas Infections/*immunology/parasitology
;
Trichomonas vaginalis/*immunology
10.The Diagnostic Performance of Liver MRI without Intravenous Contrast for Detecting Hepatocellular Carcinoma: A Case-Controlled Feasibility Study.
Seunghee HAN ; Joon Il CHOI ; Michael Yong PARK ; Moon Hyung CHOI ; Sung Eun RHA ; Young Joon LEE
Korean Journal of Radiology 2018;19(4):568-577
OBJECTIVE: To preliminarily evaluate the diagnostic performance of an unenhanced MRI for detecting hepatocellular carcinoma (HCC) with a case-control study design. MATERIALS AND METHODS: The case group consisted of 175 patients with initially-diagnosed HCC, who underwent a 3T liver MRI. A total of 237 HCCs were identified. The number of HCCs that were smaller than 1 cm, 1 cm ≤ and < 2 cm, and ≥ 2 cm were 19, 105, and 113, respectively. For the control group, 72 patients with chronic liver disease, who did not have HCC, were enrolled. Two radiologists independently reviewed the T2 half-Fourier acquisition single-shot turbo spin echo, T2 fast spin echos with fat saturation, T1 gradient in- and out-of-phase images, and diffusion-weighted images/apparent diffusion coefficient maps to detect HCC. Per-patient analyses were performed to evaluate the sensitivity and specificity of the non-contrast MRI for diagnosing HCC. Furthermore, the per-lesion sensitivity was also calculated according to tumor size. RESULTS: In the per-patient analyses, the sensitivity and specificity of reader 1 were 86.3% (151/175) and 87.5% (63/72), respectively; while those of reader 2 were 82.9% (145/175) and 76.4% (55/72), respectively. When excluding HCCs smaller than 1 cm, the sensitivity of reader 1 and 2 were 88.0% (147/167) and 86.2% (144/167), respectively. In the per-lesion analyses, the sensitivities of reader 1 and reader 2 were 75.9% (180/237) and 70.5% (167/237), respectively. CONCLUSION: The per-patient sensitivity and specificity of non-contrast MRIs were within a reasonable range for the initial diagnosis of HCC. Non-contrast MRIs may have a potential for surveillance of HCC. Further confirmatory diagnostic test accuracy studies are needed.
Carcinoma, Hepatocellular*
;
Case-Control Studies*
;
Diagnosis
;
Diagnostic Tests, Routine
;
Diffusion
;
Feasibility Studies*
;
Humans
;
Liver Diseases
;
Liver*
;
Magnetic Resonance Imaging*
;
Mass Screening
;
Sensitivity and Specificity