Nam Ju Lee

Kyung Hee University, Seoul, Seoul, South Korea

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Publications (16)

  • Nam Ju Lee · Harold Litt
    [Show abstract] [Hide abstract] ABSTRACT: Chest pain is the second most common emergency department (ED) presentation in the United States. Cardiac computed tomography angiography (CCTA) now plays an important role in the evaluation of patients with suspected acute coronary syndrome in the ED setting. In this article, we review the available techniques focused on the use of CCTA to evaluate patients fosr coronary atherosclerosis for timely triage of acute chest pain.
    Article · Sep 2015 · The international journal of cardiovascular imaging
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    Luckmini Liyanage · Nam Ju Lee · Tessa Cook · [...] · Yuchi Han
    [Show abstract] [Hide abstract] ABSTRACT: There is an established sex difference in cardiovascular disease among pre-menopausal women and age-matched men, with men having greater susceptibility to cardiovascular and coronary artery disease. Cardiovascular calcification may be linked to the atherosclerotic process and resulting disease, but the sex difference regarding coronary artery disease susceptibility and calcification is incompletely understood. We thought to measure calcium volume in different chest vascular beds in very elderly men and women with severe aortic stenosis (AS). Computed tomography scans of 94 patients with severe AS were calcium volume scored on Aquarius iNtuition Terarecon (Terarecon Inc., CA, USA) work stations. Coronary beds, aortic valve, mitral valve apparatus, and the thoracic aorta were examined. A significant sex difference in the mean total calcium volume of the coronary arteries was found in elderly (p = 0.001), with men having greater levels of calcification. There is also a significant sex difference in the amount of aortic valve calcium (p = 0.003). Furthermore, aortic and coronary calcification was independently correlated with sex. This study demonstrates a significant sex impact on calcification in the coronary beds and aortic valve in elderly patients with severe AS.
    Full-text Article · Aug 2015 · The international journal of cardiovascular imaging
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    Nam Ju Lee · Bongju Lee · Harold Litt
    Full-text Article · Feb 2015 · Journal of Cardiovascular Magnetic Resonance
  • [Show abstract] [Hide abstract] ABSTRACT: PURPOSE We evaluated hyperthyroid pts found to have hypofunctioning thyroid nodules on scintigraphy and correlated with ultrasonographic findings and the likelihood of malignancy. METHOD AND MATERIALS We reviewed 3,298 thyroid scintigraphs done between 1/1991 and 10/2012. Of these, 1,506 were done for hyperthyroidism and 61 pts were found to have hypofunctioning nodules. Of these, 50 pts underwent US within 6 months. We excluded 6 pts with clinically transient hyperthyroidism and 4 pts without tissue confirmation or follow up studies to support benign nature. Finally, we collected 40 pts; age 18-79, median age 53 (F:37, M:3). Biopsy was performed on 22 pts. Seven pts had both biopsy and surgery. Three pts had surgery only. Four pts were stable on follow up US (25months-10yrs, median: 68months). Ablation therapy was done for 2 pts. Corresponding US was evaluated for multiplicity (single vs. multiple), meeting the currently recommended biopsy criteria, composition (solid vs. mixed), microcalcifications, coarse calcifications, and interval growth. For multiple nodules, we evaluated a dominant nodule. SAS version 9.3 was used for statistical analysis. RESULTS Twenty three out of 40 nodules were solitary on scintigraphy and 5 out of 23 were solitary on US. Nine pts did not show corresponding nodules on US (22.5%). Surgery proved 6 cancers (15%); 3 were proven on biopsy prior to the surgery and 3 were occult cancers found surgically. Five out of 6 cancer pts had a single nodule on scintigraphy. Of 31 pts with a sonographic nodule, 18 nodules met the sonographic biopsy criteria and 3 out of 18 nodules had cancer on biopsy (OR 6.1, 95 % CI 0.3-129.0). Malignancy was proven in 2 of 5 sonographic solitary nodules (OR 16.7, 95 % CI 1.1-243.7) and 3 of 9 solid nodules (OR 24.2, 95 % CI 1.1-532.0) on biopsy. There was a statistically significant relationship between cancer and both solid composition (G2=8.25, p<0.05) and singularity (G2=4.50, p<0.05) in independence test. CONCLUSION In hyperthyroid pts, scintigraphic hypofunctioning nodules need tissue confirmation when the nodule meets the biopsy criteria on US. Our study also revealed a significant correlation between ultrasonographic solid or solitary nodule and malignancy in the setting of hyperthyroidism. CLINICAL RELEVANCE/APPLICATION Tissue confirmation is recommended to exclude malignancy when the scintigraphic hypofunctioning thyroid nodules are single, solid, or meeting biopsy criteria on US.
    Conference Paper · Dec 2013
  • Ju Young Song · Seung Eun Lee · Nam Ju Lee · [...] · Hyun-Jong Ahn
    [Show abstract] [Hide abstract] ABSTRACT: Acrolein is an alpha, beta-unsaturated aldehyde present in cigarette smoke, and is also a product of lipid peroxidation. Heme oxygenase-1 (HO-1) plays critical roles in preventing oxidative stress and other cellular functions, and induces viability and proliferation of tumor cells. Acrolein is well-known to induce HO-1, although the signal pathway has not been fully elucidated. This study elucidated the involved signaling and acrolein’s cytoprotective effects in human hepatocellular carcinoma (HepG2) cells. Cells were treated with acrolein to induce HO-1, whose expression was measured by Western blot, RT-PCR and immunofluorescence staining analyses. Low concentrations of acrolein remarkably increased HO-1 mRNA and protein levels. Acrolein-mediated HO-1 induction was notably decreased by rottlerin and SB203580, selective inhibitors of PKC-δ and p38 MAPK, respectively. Furthermore, the cells displayed an increased arrest at the G0/G1 phase of the cell-cycle. The data indicates that acrolein enhances HO-1 expression via PKC-δ and p38 MAPK signaling. Acrolein may provide a cytoprotective effect via the expression of HO-1 in HepG2 cells. KeywordsAcrolein-Heme oxygenase-1-Human hepatocellular carcinoma-Cytoprotective
    Article · Jun 2010 · Molecular and Cellular Toxicology
  • Seung Eun Lee · Nam Ju Lee · Sun Hee Lee · [...] · Yong Seek Park
    [Show abstract] [Hide abstract] ABSTRACT: Uncaria rhynchophylla (UR) is an herbal plant that has been used widely to treat stroke, hypertension and atherosclerosis. Upregulated heme oxygenase-1 (HO-1) plays a crucial role in cytoprotection and anti-inflammatory responses in a variety of pathological models. In this study, we investigated upregulation of HO-1 by UR, which is inducible and cytoprotective enzyme in RAW 264.7 macrophages. Upregulation of HO-1 and signal pathways were examined by western blots, RT-PCR and immunofluorescence staining. Treatment of UR induced HO-1 protein expression and Nrf2 nuclear translocation in RAW 264.7 macrophages. HO-1 induction was strongly inhibited by the suppression of p38 MAPK and ERK activity. Additionally, rottlerin, an inhibitor of protein kinase C δ (PKC δ), abolished the upregulation of HO-1 protein levels. From the above results, it is suggested that UR may exert a cytoprotective effect via the upregulation of HO-1 in RAW 264.7 macrophages. Keywords Uncaria rhynchophylla -Heme oxygenase 1-Macrophage-Nrf2
    Article · Mar 2010 · Molecular and Cellular Toxicology
  • Nam Ju Lee · Seung Eun Lee · Cheung-Seog Park · [...] · Yong Seek Park
    [Show abstract] [Hide abstract] ABSTRACT: Acrolein, a known toxin in cigarette smoke, is the most abundant electrophilic alpha, beta-unsaturated aldehyde to which humans are exposed in a variety of environmental pollutants, and is also product of lipid peroxidation. Increased unsaturated aldehyde levels and reduced antioxidant status plays a major role in the pathogenesis of various diseases such as diabetes, Alzheimer's and atherosclerosis. The findings reported here show that low concentrations of acrolein induce heme oxygenase-1 (HO-1) expression in RAW 264.7 macrophages. HO-1 induction by acrolein and signal pathways was measured using reverse transcription-polymerase chain reaction, Western blot and immunofluorescence staining analyses. Inhibition of extracellular signal-regulated kinase activity significantly attenuated the induction of HO-1 protein by acrolein, while suppression of Jun N-terminal kinase and p38 activity did not affect induction of HO-1 expression. Moreover, rottlerin, an inhibitor of protein kinase delta, suppressed the upregulation of HO-1 protein production, possibly involving the interaction of NF-E2-related factor 2 (Nrf2), which has a key role as a HO-1 transcription factor. Acrolein elevated the nuclear translocation of Nrf2 in nuclear extraction. The results suggest that RAW 264.7 may protect against acrolein-mediated cellular damage via the upregulation of HO-1 which is an adaptive response to oxidative stress.
    Article · Sep 2009 · Molecular and Cellular Toxicology
  • Nam Ju Lee · Seung Eun Lee · Sun Hee Lee · [...] · Young Seek Park
    Article · Sep 2009 · Molecular and Cellular Toxicology
  • Seung Eun Lee · Sun Hee Lee · Nam Ju Lee · [...] · Yong Seek Park
    Article · Sep 2009 · Molecular and Cellular Toxicology
  • Kyung Hyun Lee · Nam Ju Lee · Soonsil Hyun · [...] · Jaehoon Yu
    [Show abstract] [Hide abstract] ABSTRACT: Give me some feedback: In vitro selection of aptamers against the H3 peptide provided specific hairpin RNAs that possess high homology with histone H3 mRNA. The identified H3 hairpin RNA binds specifically to the H3 peptide with micromolar affinity and dose-dependently inhibits in vitro translation of the H3 protein. Consequently, the hairpin RNA and H3 peptide are one of the rare cis- and trans-elements on coding regions found among housekeeping proteins in higher eukaryotes.
    Article · May 2009 · ChemBioChem
  • Seung Eun Lee · Sun Hee Lee · Nam Ju Lee · [...] · Yong Seek Park
    Conference Paper · Jan 2009
  • Sun Hee Lee · Seung Eun Lee · Nam Ju Lee · [...] · Yong Seek Park
    Conference Paper · Jan 2009
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    [Show abstract] [Hide abstract] ABSTRACT: Primary liposarcoma of the liver is extremely rare. We report here on a case of primary well-differentiated liposarcoma in the left hepatic lobe of a 63-year-old woman. Abdominal ultrasonography showed a well-defined, echogenic, round mass. Abdominal computed tomography (CT) and magnetic resonance (MR) images showed an almost fatty, lobulated mass with a few, random distributed vascular structures and a small area of nodular enhancement. The resected tumor appeared as a well-defined, round, tan-yellow mass. Histological analysis showed a well-differentiated liposarcoma.
    Full-text Article · Jan 2008 · Acta Radiologica
  • Soonsil Hyun · Hyun Jin Kim · Nam Ju Lee · [...] · Jaehoon Yu
    [Show abstract] [Hide abstract] ABSTRACT: The combinatorial introduction of N,N-dimethyl-Lys groups into Lys-rich α-helical peptides and measuring affinities against RRE RNA were carried out. Peptide-g, in which two Lys were replaced by N,N-dimethyl-Lys at 3 and 9 positions, showed low-nanomolar affinity, which is almost the same value as Rev peptide, the natural RRE ligand. Moreover, peptide-g displays a compatible binding specificity as Rev peptide. The effects of the positions of Lys N,N-dimethylation on the specificity of RNA binding could serve as the basis of a new strategy for the design of novel agents against RNAs. The results support that nature may use N-methylation as a post-translational modification to enhance specific peptide−RNA interactions.
    Article · May 2007 · Journal of the American Chemical Society
  • Nam Ju Lee · Hoon Ji · Jorge Mendoza · E. Kent Yucel
    [Show abstract] [Hide abstract] ABSTRACT: PURPOSE/AIM 1. To review various causes of persistent or recurrent post cholecystectomy pain. 2. To discuss optimal MRI techniques to evaluate patients with pain after cholecystectomy. CONTENT ORGANIZATION 1. Review post cholecystectomy symptoms and causes of recurrent or persistent pain. 2. MRI protocols to evaluate patients with post cholecystectomy pain. 3. Demonstrate MRI findings of patients with persistent or recurrent pain after cholecystectomy including Sphincter of Oddi dysfunction, duodeno-gastric reflux, stones in the remnant cystic duct/gallbladder, CBD stones, and bile duct strictures among others. SUMMARY 1. Gd-EOB-DTPA-enhanced MRI has a novel utility in evaluating post cholecystectomy patients. 2. Duodeno-gastric bile reflux and Sphincter of Oddi dysfunction can be evaluated with Gd-EOB-DTPA-enhanced MRI. 3. In patients with history of laparoscopic cholecystectomy, stones within a remnant gallbladder/ cystic duct can be evaluated with MRI.
    Conference Paper ·
  • Nam Ju Lee · John Finley · E. Kent Yucel · [...] · Martin Maron
    [Show abstract] [Hide abstract] ABSTRACT: PURPOSE/AIM 1. To review the pathophysiology of the LV outflow obstruction. 2. To review MRI and echocardiographic findings of LV outflow obstruction and mitral valvular abnormalities in patients with hypertrophic cardiomyopathy. CONTENT ORGANIZATION 1. Anatomy and pathophysiology of the LV outflow obstruction. 2. MRI findings of mitral valvular abnormalities: systolic anterior motion of mitral leaflets (SAM), grades of SAM, mitral regurgitation, factors contributing to the severity of the mitral regurgitation. SUMMARY 1. SAM causes both subaortic obstruction and mitral regurgitation. 2. The degree of mitral regurgitation in patients with SAM is determined by disproportionate degrees of anterior and posterior leaflet SAM, the ratio of leaflets length, and range of motion of the posterior leaflet dictated by its chordal and papillary muscle connections. 3. Identification of causes of outflow tract obstruction and mitral regurgitation help with planning surgical intervention.
    Conference Paper ·