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Biomedical subjects

J E Kim

Publications and source records attributed to J E Kim.

At least 19 recordsLinked to original sources
PubMed2006

Clinical analysis of vertebrobasilar dissection.

BACKGROUND: The natural history of vertebrobasilar artery dissection (VAD) is not fully known. The purpose of this study was to review the clinical outcome of the patients with VAD, then to propose an appropriate management strategy for VAD. METHOD: From 1992 to 2004, 35 VAD patients admitted to our institutes were retrospectively reviewed. There were 28 men and 7 women, whose age ranged from 4 to 67 years with a mean age of 44 years. Angiography was assessed to document the shape, and location of the dissecting aneurysm with respect to the posterior inferior cerebellar artery (PICA). A modified Rankin score was assigned for functional outcome. The functional outcome scores were analyzed according to the patient's age, gender, hypertension history, the pattern of initial manifestation, angiographic shape of VAD, angiographic location of VAD, treatment modality. FINDINGS: There was no statistically significant difference between the functional outcome with age, gender, trauma history and past medical history of hypertension. Of 35 patients, 22 presented with SAH, 11 with ischemic symptoms and 2 were incidentally detected. The patients without SAH had a better functional outcome than those with SAH (p = 0.029). There was statistical significance between Hunt-Hess (H-H) grade and clinical outcome (p = 0.032). The shape and location of VAD was not significantly related to the functional outcome (p = 0.294, 0.840). But all the cases of rebleeding and mortality (except one case with initially poor H-H grade) developed exclusively in patients with aneurysms. There was no statistically significant correlation between the treatment modality and the outcome (p = 0.691). CONCLUSION: The VAD patients with SAH would be recommended to be managed by either surgical or endovascular treatment, but those without SAH, could be managed conservatively with antiplatelet therapy and/or anticoagulation.

Adolescent↗
PubMed2005

Microcystic meningiomas: radiological characteristics of 16 cases.

BACKGROUND: As a rare subtype of meningioma, only a few reports deal with radiological characteristics of microcystic meningiomas and the problem remains controversial. The authors have analyzed the radiological findings of a series of microcystic meningiomas with a special focus on magnetic resonance images (MRI) and conventional angiography. METHOD: Sixteen patients of histologically proven microcystic meningiomas were included. Analysis of preoperative MRI including signal intensity characteristics, enhancement patterns and peritumoural edema were performed and correlated with angiographic and histological findings. Peritumoural edema was graded using edema index (EI) which was defined as the ratio of VE/VT. FINDINGS: The tumours were uniformly visualized as a high-signal mass lesion in T2-weighted images and as a low-signal mass lesion in T1-weighted images regardless of tumour vascularity shown by angiography. T2-weighted images revealed that peritumoural brain edema was severe in 11, moderate in 1, mild in 2 and negligible in 2 patients and this was closely related to the co-existence of irregular tumour marginal enhancement. However, other features failed to distinguish these lesions from other subtypes of meningioma. CONCLUSIONS: The cases presented demonstrate that characteristic MRI findings suggestive of microcystic meningiomas are; (1) low signal intensity mass in T1- and high signal intensity mass in T2-weighted images; (2) high incidence of peritumoural edema.

Adult↗
PubMed2005

Seasonal variation of chemical composition in fine particles at Gosan, Korea.

PM2.5 aerosol samples were collected at Gosan in Jeju Island during six intensive measurement periods between November 2001 and August 2003. In order to investigate the chemical composition of fine particles, major ion components, trace elements, and elemental and organic carbon were analyzed. Quite different seasonal characteristic in the chemical composition of fine particles was observed. The concentration of most secondary aerosol components showed a summer minimum and a winter maximum with higher correlation between them at Gosan. This fact clearly reveals the possibility of long-range transport of such pollutants in winter. On the other hand, OC and EC had the highest concentration and good correlation with ion components, such as K+, Ca2+ in fall. It means that biomass burning could significantly influence the ambient fine carbonaceous particulate in fall, which was primarily long-range transported.

Aerosols↗
PubMed2005

Expression and prognostic implications of cell cycle regulatory molecules, p16, p21, p27, p14 and p53 in germinal centre and non-germinal centre B-like diffuse large B-cell lymphomas.

AIMS: To evaluate the different expression patterns and the prognostic significance of cell cycle regulatory molecules in diffuse large B-cell lymphomas (DLBCLs) of germinal centre (GC) and non-GC phenotypes. METHODS AND RESULTS: Tissue microarray slides composed of 126 extranodal and 88 nodal DLBCLs were immunostained for p16, p21, p27, p14 and p53. DLBCLs were classified into GC and non-GC phenotype according to the immunohistochemical expression of bcl-6, CD10, and MUM1. Aberrant expression of p53 was more frequent in the GC phenotype in nodal cases (P = 0.038), and the loss of p16, p21 and p14 expression was significantly more common in the non-GC phenotype (P = 0.004, P = 0.001, P < 0.001). Concurrent disruptions of the p16-Rb and p14-p53 pathways as represented by the immunoprofile of p16/p14/p53 (-/-/+) were associated with a poor prognosis in the GC phenotype [mean survival 31 months in the p16/p14/p53 (-/-/+) group versus 62 months in the other groups, P =0.0485]. CONCLUSIONS: The expression and prognostic implications of cell cycle regulatory molecules differ between GC and non-GC phenotypes in DLBCLs. The immunoprofile of p16/p14/p53 (-/-/+) within the GC phenotype of DLBCLs can be defined as a poor prognostic subgroup.

Adolescent↗
PubMed2005

Caveolin-1 is down-regulated and inversely correlated with HER2 and EGFR expression status in invasive ductal carcinoma of the breast.

AIMS: To evaluate the caveolin-1 status of invasive ductal carcinoma and its correlation with other important parameters of breast carcinogenesis. Caveolin-1, the main structural protein of caveolae, is involved in the regulation of several intracellular signalling pathways and also functions as a tumour suppressor in breast carcinogenesis. METHODS AND RESULTS: One hundred and thirty cases of invasive ductal carcinomas with matched normal breast tissue were evaluated immunohistochemically for caveolin-1 expression. Using a tissue microarray, caveolin-1 expression was also correlated with the expression of other antigens such as eostrogen receptor, progesterone receptor, epidermal growth factor receptor (EGFR), HER2, beta-catenin, E-cadherin, p53, Ki67 and with clinicopathological parameters. Immunohistochemical results showed strong expression of caveolin-1 in all normal breast epithelial cells, but a reduction of caveolin-1 expression in 56 cases (43.1%) of invasive ductal carcinoma. Furthermore, a statistically significant inverse correlation between caveolin-1 and EGFR and HER2 was noted (P < 0.001). CONCLUSIONS: Our results indicate a reduction in caveolin-1 expression in invasive ductal carcinoma of the breast, which supports in vitro studies of its role as a tumour suppressor. Caveolin-1 also shows an inverse correlation with EGFR and HER2, which fits with its function as a negative regulator of signal transduction.

Adult↗
PubMed2005

Molecular cloning and characterization of bovine PRKAG3 gene: structure, expression and single nucleotide polymorphism detection.

The protein kinase adenosine monophosphate-activated gamma3-subunit (PRKAG3) gene encodes a muscle-specific isoform of the regulatory gamma-subunit of adenosine monophosphate-activated protein kinase, which plays a key role in regulating energy homeostasis in eucaryotes. It is well known that mutations in the PRKAG3 gene affect high glycogen content in the porcine skeletal muscle and, consequently, meat quality. The genomic structure and sequence of the bovine PRKAG3 were analysed from a Korean cattle BAC clone. The bovine PRKAG3 gene comprises 13 exons and spans approximately 6.8 kb on BTA2. From 5' and 3'-rapid amplification of cDNA ends experiments, the full-length cDNA of bovine PRKAG3 has been identified, encoding a deduced protein of 465 amino acids. Two splice isoforms, generated by the alternative splicing of exon 2, were also identified. Northern blot analysis demonstrated that, similar to other species, the bovine PRKAG3 transcript was only expressed in skeletal muscle. Seven single nucleotide polymorphisms, including two previously identified variants, were detected in four Bos taurus cattle breeds. The bovine PRKAG3 gene described in this study may be involved in muscle-related genetic diseases or meat quality traits in cattle.

Amino Acid Sequence↗
PubMed2004

Spectrum of lymph node pathology in adult onset Still's disease; analysis of 12 patients with one follow up biopsy.

BACKGROUND: Adult onset Still's disease (AOSD) is a rare systemic inflammatory disorder of unknown aetiology, frequently accompanying multiple lymphadenopathy. It often mimics malignant lymphoma, and immunohistochemical and molecular studies are needed for definite diagnosis. AIMS: To aid in diagnosis and understand the pathogenesis of the disease by clarifying lymph node (LN) pathology in AOSD. METHODS: Thirteen biopsies (one follow up biopsy) and medical records of 12 patients were reviewed. Immunohistochemistry, polymerase chain reaction for T cell receptor gamma chain (TCRgamma) and immunoglobulin heavy chain gene rearrangement, and Epstein-Barr virus in situ hybridisation were performed. RESULTS: Histologically, LN lesions were classified into four patterns. The most common (six biopsies) showed paracortical hyperplasia, with prominent vascular proliferation, scattered large B/T immunoblasts, and infiltration by reactive lymphocytes and inflammatory cells. In the second pattern (two biopsies), paracortical hyperplasia was accompanied by massive sinus histiocytosis and S-100 positive histiocyte aggregates. The third pattern (three patients) showed an exuberant immunoblastic reaction, in the form of patchy/diffuse infiltration of large T immunoblasts with high mitotic activity, although clonal rearrangement of the TCRgamma gene was not detected. The fourth pattern showed distinct follicular hyperplasia (two cases). One patient with a follow up biopsy showed a pattern change from pronounced follicular hyperplasia to atypical paracortical hyperplasia. CONCLUSIONS: AOSD LN lesions show a dynamic histological spectrum, including atypical paracortical hyperplasia, burnt out histiocytic reaction, exuberant immunoblastic reaction, and follicular hyperplasia. During the course of disease, LN reactivity changes and mixed B and T cells are involved in the pathogenesis.

Adolescent↗
PubMed2003

The significance of gemistocytes in astrocytoma.

BACKGROUND: A retrospective clinical analysis of astrocytomas which contained a significant proportion of gemistocytes was carried out in order to evaluate their effect on prognosis, and other factors influencing prognosis. METHOD: From 253 consecutive cases of astrocytic tumours in adults, 25 were selected who had more than 20% gemistocytes in every high-power field examined. 9 of these had anaplasia, the remainder did not. They were divided into two groups according to the proportion of gemistocytes; group A, contained more than 60% gemistocytes, and group B, had between 20 and 60% gemistocytes. TUNEL and immunohistochemical staining for PCNA, p53, Ki-67, bcl-2 were performed in the 20 available cases. FINDINGS: The median follow-up period was 46 months. There were 14 recurrences, with a median time to recurrence of 15 months. Thirteen repeat operations were performed in nine cases, and two cases showed recurring malignant transformation. The overall median survival time following diagnosis was 73 months and the 5-year survival rate was 52%. There were no significant differences in median survival between groups A and B with different proportions of gemistocytes. On the other hand the median survival of the gemistocytic astrocytomas with anaplasia was 25 months, compared with 158 months for those without anaplasia (p=0.0005). The significant impact of anaplasia on survival persisted in both groups. There were no significant differences in immunohistochemical staining between the two groups, with the exception of staining for Ki-67 (means of the two groups: group A 1.40; group B 2.50). CONCLUSIONS: It is suggested that the proportion of gemistocytes does not itself affect prognosis.

Adult↗
PubMed2003

Stereotactic biopsy for intracranial lesions: reliability and its impact on the planning of treatment.

BACKGROUND: The authors present a retrospective analysis of 308 computed tomography (CT)-guided stereotactic biopsies in 300 patients in order to evaluate the reliability and efficacy of the stereotactic biopsy for intracranial lesions. METHOD: All patients were suffering from undetermined intracranial lesions and treated at Seoul National University Hospital between January 1993 and December 1999. Age ranged from three to 79 years (mean 41); the male to female ratio was 180:120. All patients underwent CT-guided stereotactic biopsy for the histological verification and/or evacuation of the cyst using Riechert-Mundinger stereotactic system. FINDINGS: Histological diagnosis was made in 275 patients (diagnostic yield 91.7%). Diagnostic yield was better in group with frozen section examination during the stereotactic procedure than the group without it (p=0.01). Neoplastic lesions were more likely to be diagnosed in stereotactic biopsy than non-neoplastic lesions (p=0.02). Among 30 patients who underwent craniotomy after the stereotactic biopsy, the histological diagnoses after the craniotomy were identical to those of the stereotactic biopsy in 29 patients (diagnostic accuracy 96.7%). Two patients died within seven days after the stereotactic biopsy (mortality 0.6%). The postoperative new neurological deficit or aggravation of the neurological status was found in 19 patients, including transient cases of seven patients (permanent morbidity rate 3.9%). Histologically malignant gliomas and deeply-located lesions were the significant risk factors for the development of complications. In 148 cases, histological diagnosis of the stereotactic biopsy was different from the preoperative clinical diagnosis. Among these cases, the treatment plan was changed after stereotactic biopsy in 81 cases. CONCLUSIONS: Stereotactic biopsy for intracranial lesions is a reliable and relatively safe procedure. It is also a very efficacious method especially in patients who need histological confirmation for the treatment.

Adolescent↗
PubMed2001

Temporospatial sequence of cellular events associated with etoposide-induced neuronal cell death: role of antiapoptotic protein Bcl-X(L).

Etoposide-induced death comprises such nuclear events as the formation of topoisomerase II-DNA cleavable complex and cytosolic events including caspase activation. By first establishing the temporospatial death sequence triggered by etoposide in a neuronal cell line, MN9D overexpressing Bcl-X(L) (MN9D/Bcl-X(L)) or control vector (MN9D/Neo), we examined whether formation of this complex is primarily responsible for cell death and at which strategic points and how Bcl-X(L) blocks etoposide-induced neuronal death. Etoposide induced death that was dependent on caspase, cycloheximide, and calpain in MN9D/Neo cells. Etoposide also induced death in enucleated MN9D/Neo cells, although this was less severe. The level of topoisomerase II-DNA cleavable complex reached at a maximum of 2 hr after etoposide treatment was identical in MN9D/Neo and MN9D/Bcl-X(L) cells. In MN9D/Neo cells, cytochrome c release into the cytosol and caspase activation occurred as early as 2 hr and 3-6 hr after etoposide treatment, respectively. Etoposide-induced DNA laddering potentially via caspase appeared as early as 12 hr after drug treatment, followed by nuclear swelling in MN9D/Neo cells (>18-20 hr). Subsequently, nuclear condensation started by 24-28 hr and became apparent thereafter. All of these events except for nuclear swelling were substantially blocked in MN9D/Bcl-X(L). At the later stage of cell death (<32-36 hr), a specific cleavage of Bax and fodrin appeared that was completely blocked by calpain inhibitor or by Bcl-X(L). Taken together, our data suggest that Bcl-X(L) prevents etoposide-induced neuronal death by exerting its anticaspase and anticalpain effect on cellular events after the formation of topoisomerase II-DNA cleavable complex that may not be a major contributor to cell death.

Apoptosis↗
PubMed2001

Wavelength dependent cis-trans isomerization in vision.

The primary event in vision is the light-driven cis-trans isomerization of the 11-cis-retinal chromophore in the G-protein coupled receptor rhodopsin. Early measurements showed that this photoisomerization has a reaction quantum yield phi of approximately 0.67 [Dartnall (1936) Proc. R. Soc. A 156, 158-170; Dartnall (1968) Vision Res. 8, 339-358] and suggested that the quantum yield was wavelength independent [Schneider (1939) Proc. Natl. Acad. Sci. U.S.A. 170, 102-112]. Here we more accurately determine phi(500) = 0.65 +/- 0.01 and reveal that phi surprisingly depends on the wavelength of the incident light. Although there is no difference in the quantum yield between 450 and 480 nm, the quantum yield falls significantly as the photon energy is reduced below 20 000 cm(-1) (500 nm). At the reddest wavelength measured (570 nm), the quantum yield is reduced by 5 +/- 1% relative to the 500 nm value. These experiments correct the long-held presumption that the quantum yield in vision is wavelength independent, and support the hypothesis that the 200 fs photoisomerization reaction that initiates vision is dictated by nonstationary excited-state vibrational wave packet dynamics.

Animals↗
PubMed2001

Ntg2 of Saccharomyces cerevisiae repairs the oxidation products of 8-hydroxyguanine.

In Escherichia coli, endonuclease III (endo III) repairs the oxidation products of 8-OHGua. However, the corresponding repair enzymes in eukaryotes have not been identified. Here we report that 8-hydroxyguanine (8-OHGua) is highly sensitive to further oxidation. We also show that Ntg2, a functional homolog of endo III in Saccharomyces cerevisiae, is capable of nicking the irradiated duplex DNA containing 8-OHGua. Moreover, Ntg2 formed a stable complex with the DNA upon incubation with NaBH(4). In contrast, Ntg1, another functional homolog of endo III, showed no such activities. These findings indicate that Ntg2 is, at least in part, responsible for repairing the oxidation products of 8-OHGua in eukaryotic cells.

Borohydrides↗
PubMed2001

Ethanol decreases the expression of mitochondrial cytochrome c oxidase mRNA in the rat.

To evaluate the molecular and cellular bases of effects of ethanol on the brain, we utilized a differential display-polymerase chain reaction. Several cDNA fragments were differentially expressed in the hippocampus of control vs. ethanol-treated rats. One of these genes was homologous to the rat mitochondrial cytochrome c oxidase mRNA. Northern blot analysis revealed that the expression of this message in the whole hippocampus was clearly lower after ethanol treatment. Using in situ hybridization, we also found that cytochrome c oxidase mRNA expression, especially in the CA1 and CA3 of the hippocampal regions, was significantly decreased by ethanol treatment. As cytochrome c oxidase is related to oxidative stress, the present study suggests that ethanol might affect the brain through modulation of an oxidative stress reaction.

Animals↗
PubMed2001

Randall-Sundrum model for self-tuning the cosmological constant.

The vanishing cosmological constant in the four-dimensional space-time is obtained in a 5D Randall-Sundrum model with a brane (B1) located at y = 0. The matter fields can be located at the brane. For settling any vacuum energy generated at the brane to zero, we need a three-index antisymmetric tensor field A(MNP) with a specific form for the Lagrangian. For the self-tuning mechanism, the bulk cosmological constant should be negative.

Journal Article↗
PubMed2001

A cofactor of tRNA synthetase, p43, is secreted to up-regulate proinflammatory genes.

An auxiliary factor of mammalian multi-aminoacyl-tRNA synthetases, p43, is thought to be a precursor of endothelial monocyte-activating polypeptide II (EMAP II) that triggers proinflammation in leukocytes and macrophages. In the present work, however, we have shown that p43 itself is specifically secreted from intact mammalian cells, while EMAP II is released only when the cells are disrupted. Secretion of p43 was also observed when its expression was increased. These results suggest that p43 itself should be a real cytokine secreted by an active mechanism. To determine the cytokine activity and active domain of p43, we investigated tumor necrosis factor (TNF) and interleukin-8 (IL-8) production from human monocytic THP-1 cells treated with various p43 deletion mutants. The full length of p43 showed higher cytokine activity than EMAP II, further supporting p43 as the active cytokine. p43 was also shown to activate MAPKs and NFkappaB, and to induce cytokines and chemokines such as TNF, IL-8, MCP-1, MIP-1alpha, MIP-1beta, MIP-2alpha, IL-1beta, and RANTES. Interestingly, the high level of p43 was observed in the foam cells of atherosclerotic lesions. Therefore, p43 could be a novel mediator of atherosclerosis development as well as other inflammation-related diseases.

Amino Acyl-tRNA Synthetases↗
PubMed2001

Resonance Raman Structural Evidence that the Cis-to-Trans Isomerization in Rhodopsin Occurs in Femtoseconds.

Picosecond time-resolved resonance Raman spectroscopy is used to probe the structural changes of rhodopsin's retinal chromophore as the cis-to-trans isomerization reaction occurs that initiates vision. Room-temperature resonance Raman spectra of rhodopsin's photoproduct with time delays from -0.7 to 20.8 ps are measured using 2.2 ps, 480 nm pump and 1.5 ps, 600 nm probe pulses. Hydrogen-out-of-plane (HOOP) modes at 852, 871, and 919 cm(-1), fingerprint peaks at 1272, 1236, 1211, and 1166 cm(-1), and a broad red-shifted ethylenic band at 1530 cm(-1) are present at the earliest positive pump-probe time delay of 0.8 ps, indicating that the chromophore is already in a strained, all-trans configuration. Kinetic analyses of both the HOOP and ethylenic regions of the photoproduct spectra reveal that these features grow in with fast ( approximately 200 fs) and slow ( approximately 2-3 ps) components. These data provide the first structural evidence that photorhodopsin has a thermally unrelaxed, torsionally strained all-trans chromophore within approximately 1 ps, and possibly within 200 fs, of photon absorption. Following this ultrafast product formation, the all-trans chromophore cools and conformationally relaxes within a few picoseconds to form bathorhodopsin. This cooling process is revealed as an ethylenic frequency blue-shift of 6 cm(-1) (tau approximately 3.5 ps) as well as an ethylenic width narrowing (tau approximately 2 ps). The ultrafast production of photorhodopsin is likely accompanied by an impulsively driven, localized protein response. More delocalized protein modes are unable to relax on this ultrafast time scale enabling the chromophore-protein complex to store the large amounts of photon energy (30-35 kcal/mol) that are subsequently used to drive activating protein conformational changes.

Journal Article↗