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Hyung-Jin Kim

Publications and source records attributed to Hyung-Jin Kim.

At least 19 recordsLinked to original sources
PubMed2007

Use of integrated 18F-FDG PET/CT to improve the accuracy of initial cervical nodal evaluation in patients with head and neck squamous cell carcinoma.

BACKGROUND: We investigated the accuracy of performing cervical nodal evaluation with using integrated (18)F-fluoro deoxyglucose positron emission tomography (PET)/CT for squamous cell carcinoma (SCC) of the head and neck as compared with using PET and contrast-enhanced CT (CECT) alone. METHODS: The presence of metastatic lymphadenopathy in each cervical nodal group (level I-VI) and the nodal (N) classification of 47 patients with SCC of the head and neck were determined by using PET, CECT, and PET/CT, respectively, and the results were verified according to the histopathologic findings. RESULTS: Among the 91 foci that had abnormal uptake on PET, the combined PET/CT images provided additional information over PET for the anatomical localization and lesion characterization of 18 sites (19.8%) in 17 patients (36.2%). PET/CT also showed the best results among the three imaging modalities for the sensitivity, specificity, and accuracy (91.8, 98.9, and 97.1%, respectively) for predicting metastatic nodes on a level-by-level analysis, and PET/CT had a higher accuracy (85.1%) for the pathologic nodal classification over the clinical examinations (68.1%) or PET (70.2%). CONCLUSIONS: Combined PET/CT images are more accurate than the PET or CECT images alone for conducting cervical node evaluation in the patients suffering with head and neck SCC.

Aged↗
PubMed2006

Heme oxygenase-1 attenuates the cisplatin-induced apoptosis of auditory cells via down-regulation of reactive oxygen species generation.

Heme oxygenase-1 (HO-1), the rate-limiting enzyme of heme catabolism, is known to modulate various cellular functions, including cytokine production, cell proliferation, and apoptosis, in stress-related conditions. However, the role of HO-1 in the auditory system remains elusive. Herein, we demonstrate that pharmacologic induction of HO-1 along with catalytic activation significantly suppressed apoptosis of HEI-OC1 cells induced by cisplatin. Studies of ectopic expression of pcDNA3-HO-1 and siRNA of HO-1 further revealed the protective role of HO-1 against cisplatin in HEI-OC1 cells. Among the catabolic metabolites of HO-1, both carbon monoxide (CO) and bilirubin were directly involved in the protective role of HO-1 against cisplatin through inhibition of reactive oxygen species generation. Furthermore, pharmacological induction of HO-1 completely prevented the destruction of outer hair cell arrays by cisplatin through a CO-dependent mechanism in organotrophic culture of the rat primary organ of Corti explants. These results suggest that HO-1 may serve as a safeguard of auditory sensory hair cells against a variety of challenges of oxidative stress, including noise trauma, presbycusis, and ototoxic drugs, respectively.

Animals↗
PubMed2006

Integrated 18F-FDG PET/CT for the initial evaluation of cervical node level of patients with papillary thyroid carcinoma: comparison with ultrasound and contrast-enhanced CT.

OBJECTIVE: To compare the diagnostic accuracy of integrated 18F-fluorodeoxyglucose PET/CT with ultrasonography (US) and contrast enhanced CT (CECT) alone in the initial evaluation of cervical lymph node levels of patients with papillary thyroid carcinoma. PATIENTS AND MEASUREMENTS: From July 2004 to March 2005, 26 consecutive patients with papillary thyroid carcinoma, confirmed by aspiration cytology analysis, underwent US, CECT and PET/CT. The sensitivity, specificity and diagnostic accuracy of the US, CECT and PET/CT studies for the final status of 312 cervical node levels (levels I-V: 260, level VI: 52) were compared by employing a generalized estimating equation test. The final status of cervical node levels was determined by the surgical pathology and follow-up data. RESULTS: At all lymph node levels (levels I-VI), PET/CT showed a sensitivity of 30.4%, a specificity of 96.2% and a diagnostic accuracy of 86.9%. The corresponding values for US and CECT were 41.3%, 97.4%, 89.1% (US) and 34.8%, 96.2%, 87.2% (CECT). Considering only the lateral cervical node group (levels I-V), PET/CT showed a sensitivity of 50.0%, a specificity of 97.0% and a diagnostic accuracy of 92.3%. The corresponding values for US and CECT were 53.9%, 97.9%, 93.5% (US) and 42.3%, 96.6%, 91.2% (CECT). The diagnostic results for US, CECT and PET/CT upon initial evaluation of the cervical lymph nodes did not differ significantly on a level-by-level basis. CONCLUSION: Our preliminary results suggest that integrated PET/CT does not provide any additional benefit when compared to US and CECT for the initial evaluation of cervical node levels in patients with papillary thyroid carcinoma.

Adolescent↗
PubMed2006

Focal thyroid lesions incidentally identified by integrated 18F-FDG PET/CT: clinical significance and improved characterization.

UNLABELLED: In this retrospective study, we investigated whether the (18)F-FDG uptake pattern and CT findings improved the accuracy over the standardized uptake value (SUV) for differentiating benign from malignant focal thyroid lesions incidentally found on (18)F-FDG PET/CT. We also defined the prevalence of these lesions and their risk for cancer. METHODS: (18)F-FDG PET/CT was performed on 1,763 subjects without a previous history of thyroid cancer from May 2003 to June 2004. Two nuclear medicine physicians and 1 radiologist interpreted PET/CT images, concentrating on the presence of focal thyroid lesions, the maximum SUV of the thyroid lesion, the pattern of background thyroid (18)F-FDG uptake, and the CT attenuation pattern of the thyroid lesion. RESULTS: The prevalence of focal thyroid lesions on PET/CT was 4.0% (70/1,763). Diagnostic confirmation was done on 44 subjects by ultrasonography (US)-guided fine-needle aspiration (n = 29) or US with clinical follow-up (n = 15). Among 49 focal thyroid lesions in these 44 subjects, 18 focal thyroid lesions of 17 subjects were histologically proven to be malignant (papillary cancer in 16, metastasis from esophageal cancer in 1, non-Hodgkin's lymphoma in 1). Therefore, the cancer risk of focal thyroid lesions was 36.7% on a lesion-by-lesion basis or 38.6% on a subject-by-subject basis. The maximum SUV of malignant thyroid lesions was significantly higher than that of benign lesions (6.7 +/- 5.5 vs. 10.7 +/- 7.8; P < 0.05). When only the maximum SUV was applied to differentiate benign from malignant focal thyroid lesions for the receiver-operating-characteristic curve analysis, the area under the curve (AUC) of PET was 0.701. All 16 focal thyroid lesions with very low attenuation or nonlocalization on CT images, or with accompanying diffusely increased thyroid (18)F-FDG uptake, were benign. When those lesions were regarded as benign lesions, irrespective of the maximum SUV, the AUC of PET/CT was significantly improved to 0.878 (P < 0.01). CONCLUSION: Focal thyroid lesions incidentally found on (18)F-FDG PET/CT have a high risk of thyroid malignancy. Image interpretation that includes (18)F-FDG uptake and the CT attenuation pattern, along with the SUV, significantly improves the accuracy of PET/CT for differentiating benign from malignant focal thyroid lesions.

Adult↗
PubMed2005

Upregulation of receptor activator of nuclear factor-kappaB ligand expression in the thymic subcapsular, paraseptal, perivascular, and medullary epithelial cells during thymus regeneration.

The receptor activator of nuclear factor (NF)-kappaB ligand (RANKL; also termed TRANCE/OPGL/ODF/TNFSF11), a new member of the tumor-necrosis factor (TNF) superfamily, was identified as a key cytokine involved in the differentiation of the immune system and the regulation of immunity as well as in bone metabolism. In particular, RANKL-deficient mice showed defects in the early differentiation of T lymphocytes, suggesting that RANKL is a novel regulator of early thymocyte development. Here, we describe the expression of RANKL during regeneration following acute involution induced by cyclophosphamide in the rat thymus. The present study demonstrates the presence and upregulated expression of the RANKL in thymic subcapsular, paraseptal, perivascular, and medullary epithelial cells during thymus regeneration. Our results suggest that the RANKL expressed in these thymic epithelial cells plays a role in the development of T cells during thymic regeneration.

Animals↗
PubMed2005

Protective effect of T-type calcium channel blocker flunarizine on cisplatin-induced death of auditory cells.

Changes in intracellular Ca2+ level are involved in a number of intracellular events, including triggering of apoptosis. The role of intracellular calcium mobilization in cisplatin-induced hair cell death, however, is still unknown. In this study, the effect of calcium channel blocker flunarizine (Sibelium), which is used to prescribe for vertigo and tinnitus, on cisplatin-induced hair cell death was investigated in a cochlear organ of Corti-derived cell line, HEI-OC1, and the neonatal (P2) rat organ of Corti explant. Cisplatin induced apoptotic cell death showing nuclear fragmentation, DNA ladder, and TUNEL positive in both HEI-OC1 and primary organ of Corti explant. Flunarizine significantly inhibited the cisplatin-induced apoptosis. Unexpectedly, flunarizine increased the intracellular calcium ([Ca2+]i) levels of HEI-OC1. However, the protective effect of flunarizine against cisplatin was not mediated by modulation of intracellular calcium level. Treatment of cisplatin resulted in ROS generation and lipid peroxidation in HEI-OC1. Flunarizine did not attenuate ROS production but inhibited lipid peroxidation and mitochondrial permeability transition in cisplatin-treated cells. This result suggests that the protective mechanism of flunarizine on cisplatin-induced cytotoxicity is associated with direct inhibition of lipid peroxidation and mitochondrial permeability transition.

Animals↗
PubMed2004

Different adsorption structures of pyridine on Si(001) and Ge(001) surfaces.

The adsorption and reaction of pyridine on the Si(001) and Ge(001) surfaces are investigated by first-principles density-functional calculations within the generalized gradient approximation. On both surfaces the N atom of pyridine initially reacts with the down atom of the dimer, forming a single bond between the N atom and the down atom. On Ge(001) such an adsorption configuration is most favorable, but on Si(001) a further reaction with a neighboring dimer occurs, resulting in formation of a bridge-type configuration. Especially we find that on Ge(001) the bridge-type configuration is less stable than the gas phase. Our results provide an explanation for a subtle difference in the adsorption structures of pyridine on Si(001) and Ge(001), which was observed from recent scanning tunneling microscopy experiments.

Journal Article↗
PubMed2004

The usefulness of cytokeratin immunohistochemistry in detection of lymph node micrometastasis in neck dissection specimens.

OBJECTIVE: Our study was designed to find out the rate and the characteristics of micrometastasis in cervical lymph nodes using immunohistochemical staining. STUDY DESIGN AND SETTING: From 69 patients, 1710 lymph nodes negative for metastasis on hematoxylin-eosin stain, were examined. Immunohistochemical stain was performed using pan-cytokeratin AE1/AE3 antibody. RESULTS: In 13 cases, occult lymph node metastasis was detected by immunohistochemical method. On retrospective review of the hematoxylin-eosin stain by the pathologist, lymph node metastasis was detected in 4 of 13 patients. CONCLUSIONS: Because the immunohistochemical method enhanced the detection rate of occult micrometastasis in cervical lymph nodes of head and neck squamous cell carcinoma patients, it may be recommended for routine diagnostic use in patient with negative for a lymph node metastasis on routine hematoxylin-eosin stain.

Adult↗
PubMed2004

4-Acetyl-12,13-epoxyl-9-trichothecene-3, 15-diol from Isaria japonica mediates apoptosis of rat bladder carcinoma NBT-II cells by decreasing anti-apoptotic Bcl-2 expression and increasing pro-apoptotic Bax expression.

We studied the effect of 4-acetyl-12,13-epoxyl-9-trichothecene-3, 15-diol (AETD) isolated from Isaria japonica, one of the most popular Chinese fungal medicines, on the induction of apoptosis in rat bladder carcinoma NBT-II cells. AETD was cytotoxic to NBT-II cells, and this cytotoxic effect appears to be attributed to its induction of apoptotic cell death, as AETD induced nuclear morphological changes and internucleosomal DNA fragmentation, and increased the proportion of hypodiploid cells and activity of caspase-3. AETD treatment also decreased the expression of the anti-apoptotic protein Bcl-2 and increased the expression of the pro-apoptotic protein Bax. These results provide important information in understanding the mechanism(s) of AETD-induced apoptosis.

Animals↗
PubMed2003

Regioselectivity in the Stille coupling reactions of 3,5-dibromo-2-pyrone.

The Stille couplings of 3,5-dibromo-2-pyrone normally take place regioselectively at C3, lower in electron density than C5, thus oxidative addition proceeds faster . When the reactions are carried out with Cu(I) in DMF or other polar aprotic solvent, however, the couplings occur predominantly at C5. The observed regiochemical reversal is attributed to the preferred formation of 5-pallado-2-pyrone intermediate which, in addition, turned out to be more reactive than 3-pallado-2-pyrone intermediate.

Journal Article↗
PubMed2003

Two novel mutations in the EPM2A gene in a Korean patient with Lafora's progressive myoclonus epilepsy.

The progressive myoclonus epilepsy of the Lafora type (LD; MIM 254780) is a rare autosomal recessive disorder characterized by epilepsy, myoclonus, progressive neurological deterioration, and the presence of periodic acid-Schiff-positive polyglucosan inclusions (Lafora bodies). Mutations in the EPM2A gene have recently been found to cause LD and about 30 or more mutations have been reported thus far. LD is relatively common in countries of the Mediterranean Basin, the Middle East, India, and Pakistan. Although a few sporadic cases with the typical LD phenotype have also been reported in the Far East including Korea and Japan, a recent effort to find mutations in Japanese LD families was not successful. In the present study, we report two novel mutations in a Korean girl with LD; a 1-bp insertion mutation (c.223insC; G75fsX107) in exon 1 and a missense mutation (c.559A>G; T187A) in exon 3 of the EPM2A gene. To our knowledge, this is the first report of a genetically confirmed case of LD in Koreans and also in the Far East.

Adolescent↗
PubMed2003

Tanshinone IIA from Salvia miltiorrhiza inhibits inducible nitric oxide synthase expression and production of TNF-alpha, IL-1beta and IL-6 in activated RAW 264.7 cells.

The inhibitory effects of tanshinone IIA, a diterpene isolated from Salvia miltiorrhiza root, on the production of nitric oxide (NO), interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha), and the expression of inducible nitric oxide synthase (iNOS) were investigated in activated RAW 264.7 cells. This compound markedly inhibited the production of NO, IL-1beta and TNF-alpha, and suppressed the expression of iNOS in a dose-dependent manner. These results suggest that the traditional use of S. miltiorrhiza as an anti-inflammatory herbal medicine may be explained, in part, by the inhibition of NO, IL-1beta, IL-6 and TNF-alpha production, and expression of iNOS.

Abietanes↗
PubMed2003

Mesectodermal leiomyosarcoma of the ciliary body.

We report a case of low-grade mesectodermal leiomyosarcoma of the ciliary body, an extremely rare tumor of neural crest origin, occurring in a 12-year-old boy. MR imaging showed a well-marginated, ovoid soft tissue mass at the right temporal ciliary body, accompanied by total retinal detachment. The mass was slightly hyperintense relative to contralateral vitreous on T1-weighted images and markedly hypointense on T2-weighted images and enhanced very well. Initial biopsy of the mass suggested a peripheral nerve sheath tumor. The mass grew rapidly after biopsy, and enucleation was performed. The final diagnosis based on histology and immunohistochemistry was a low-grade mesectodermal leiomyosarcoma. To our knowledge, this is the first reported case of a malignant form of mesectodermal leiomyoma of the ciliary body.

Child↗
PubMed2002

MR imaging of the alar ligament: morphologic changes during axial rotation of the head in asymptomatic young adults.

OBJECTIVE: . The alar ligament plays a critical role in limiting the axial rotation of the head, the left alar ligament being stretched on rotation to the right and vice versa. The purposes of this study were to assess the usefulness of MR imaging in demonstrating the alar ligament and also to identify its morphologic changes during axial rotation of the head in asymptomatic young volunteers. DESIGN AND PATIENTS: . Twenty-two healthy volunteers participated in this study. All subjects underwent four series of contiguous fast spin echo density-weighted MR images with a 2 mm slice thickness including axial and coronal images with the head in neutral position, and coronal images with alternate head rotation to the right and left. The alar ligaments seen on each series of MR images were visually graded 0-2, and grade comparisons were performed between the four series of MR images. We also assessed the morphologic changes of the alar ligament on coronal images during axial rotation of the head. RESULTS: . Grade comparisons for the demonstration of the alar ligament revealed that each of three series of coronal images was statistically significantly better in grade than axial images. During axial rotation of the head, MR images showed rather constant morphologic changes of the alar ligament: elevation and wrapping of the contralateral alar ligament around the dens, associated with slightly upward movement of C1-C2 on that side. This wrap-around effect of the contralateral alar ligament in relation to the dens sometimes caused the apparent shortening of the alar ligament on that side. CONCLUSION: . Reliable assessment of the anatomy and function of the alar ligament can be achieved with MR imaging, preferably in coronal planes. MR imaging with the aid of a functional study may be a valuable imaging modality in the evaluation of alar ligament failure.

Adult↗
PubMed2002

1,2,3,4,6-Penta-O-galloyl-beta-D-glucose protects rat neuronal cells (Neuro 2A) from hydrogen peroxide-mediated cell death via the induction of heme oxygenase-1.

The root of Paeonia suffruticosa ANDREWS is an important Chinese crude drug used in many traditional prescriptions. 1,2,3,4,6-Penta-O-galloyl-beta-D-glucose (PGG), a major component of this crude drug, has been shown to possess potent anti-oxidant, anti-mutagenic and anti-proliferative effects. In the present study, we examined the effect of PGG on the expression of neuronal heme oxygenase-1 (HO-1), an inducible stress protein that degrades heme to the neuroactive molecule, carbon monoxide and the anti-oxidant, biliverdin. Exposure of Neuro 2A cells to PGG (10-50 microM) resulted in a concentration- and time-dependent induction of HO-1 mRNA, and protein expressions and heme oxygenase activity. Interestingly, pretreatment of the neuronal cells with PGG resulted in enhanced cellular resistance to hydrogen peroxide. This cytoprotective effect was reversed by zinc protoporphyrin IX, an inhibitor of heme oxygenase. This study showed that PGG could protect neuronal cells from oxidative stress via the induction of HO-1 gene expression.

Animals↗
PubMedDate not supplied

Chronic, reactive conditions of the oral cavity simulating mucosal carcinomas: CT and MR imaging findings with pathologic correlation in five patients.

To investigate the radiologic and pathologic findings of chronic, inflammatory, reactive conditions of the oral cavity, which clinically and radiologically simulate mucosal malignancy, computed tomography (CT; n=4) and magnetic resonance (MR; n=2) images, as well as surgical specimens, obtained from five patients with surgically proved, chronic inflammatory mass of the oral cavity were retrospectively reviewed. All patients had a palpable mass or ulcerative lesion in the oral cavity. On CT and MR images, all three lesions in the oral tongue and one lesion in the retromolar trigone were seen as a superficial, ill-marginated, well-enhancing ellipsoid or focal soft tissue mass. Pathologic examinations revealed various depths and degrees of acute and chronic inflammation, granulation tissue, and fibrosis in the subepithelial stroma, accompanied by pseudoepitheliomatous hyperplasia in these four patients. In the remaining one patient with lesion in the hard palate, CT showed a relatively well-marginated, well-enhancing soft tissue mass, which histologically proved to be irritation fibroma. Neither clinical nor radiologic manifestations could afford clues to make the correct diagnosis, which therefore should rely on histology. Some forms of chronic, inflammatory, reactive conditions of the oral cavity are nearly indistinguishable from the malignant tumors both clinically and radiologically. Knowledge of this entity may obviate the unnecessary and somewhat disfiguring operation.

Adult↗