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Biomedical subjects

Won Kim

Publications and source records attributed to Won Kim.

65 records · Page 4Linked to original sources
PubMed2003

An elevated value of C-reactive protein is the only predictive factor of restenosis after percutaneous coronary intervention.

BACKGROUND: The current techniques for percutaneous coronary interventions (PCI) remain limited by restenosis. Recent studies have provided evidence of inflammation playing a role in the pathogenesis of cardiovascular disease. METHODS: Whether inflammatory markers are predictors of subsequent restenosis were prospectively tested in 272 consecutive patients with angiographically proven coronary artery disease. Patients having undergone PCI at Chonnam National University Hospital, between Sept. 1999 and Mar. 2001, were divided into two groups according to the occurrence of restenosis on a follow-up coronary angiogram: Group I were patients with restenosis (n = 99, 59.5 +/- 10.8 years, M:F = 77:22) and Group II were those without restenosis (n = 173, 58.8 +/- 10.2 years, M:F = 131:42). The IgG seropositivity, cytomegalovirus (CMV) titers, C. pneumoniae. H. pylori and levels of C-reactive protein (CRP) were compared between the two groups. RESULTS: There were no statistical differences in the seropositivity of the CMV IgG C. pneumoniae IgG and H. pylori IgG between the two groups (Groups I vs. II: 100 vs. 100%, 24.7 vs. 25.7% and 62.2 vs. 63.7%, respectively). Of the angiographic parameters, a low Thrombolysis in Myocardial Infarction (TIMI) flow (TIMI 0 or 1) was more common in Group I than Group II (p = 0.038). The patients with an elevated CRP (> 0.5 mg/dL) were more common in Group I than Group II (57.6 vs. 36.4%, p = 0.001), with the CRP values being higher in Group I than Group II (3.3 +/- 5.8 vs. 1.3 +/- 2.6 mg/dL, p = 0.001). According to a multiple logistic regression analysis, the CRP was the only predictor of restenosis, with an odds ratio of 2.1169 (95% C.I. 1.2062-3.7154, p = 0.009). CONCLUSION: The CRP value is the most important predictor of restenosis after PCI.

Angioplasty, Balloon, Coronary↗
PubMed2003

The dimensions of indexing.

Indexing of documents is an important strategy intended to make the literature more readily available to the user. Here we describe several dimensions of indexing that are important if indexing is to be optimal. These dimensions are coverage, predictability, and transparency. MeSH terms and text words are compared in MEDLINE in regard to these dimensions. Part of our analysis consists in applying AdaBoost with decisions trees as the weak learners to estimate how reliably index terms are being assigned and how complex the criteria are by which they are being assigned. Our conclusions are that MeSH terms are more predictable and more transparent than text words.

Abstracting and Indexing↗
PubMed2002

Intraspecific hybridization of Anopheles sinensis (Diptera: Culicidae) strains from Thailand and Korea.

Anopheles (Anopheles) sinensis [Wiedemann (1828)] is a member of the hyrcanus species group, and it has been incriminated as the natural or experimental malaria vectors in the Republic of Korea, Japan, China, and Indonesia. In Thailand, however, An. sinensis seems to be of little medical importance. Hybridization tests among the three iso-female lines (isolines) of An. sinensis [i.e., Form A (X, Y1) and Form B (X, Y2) (Thailand strain), and Form B (X, Y2) (Korean strain)] were established based on two distinct types of metaphase chromosomes and geographical differences The chromosomal form of the Korean strain was first identified from this study. Results of reciprocal and back crosses indicated that both karyotypic forms of theAn. sinensis Thailand and Korean strains were genetically compatible, and provided viable progenies and completely synaptic polytene chromosomes. The sequences of the rDNA internal-transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit II (COII) among the An. sinensis strains were nearly identical to each other, and the intraspecific sequence variability was very low (0.0-0.6%). Sequence comparisons among the cryptic inter-species (i.e., An. sinensis, An. lesteri, and An. yatsushiroensis), however, revealed extensive divergence, and the intraspecific variability ranged from 12.2 to 34.6%. Therefore, it is concluded from these results and previous vector ability studies that the An. sinensis Forms A and B exhibit cytological polymorphic races that have different vector abilities in their transmission of malaria, depending on their geographical locations.

Animals↗
PubMed2002

A single mitochondrial lineage is shared by morphologically and allozymatically distinct freshwater Corbicula clones.

Despite that the exotic invasion and rapid range expansion of Asian freshwater Corbicula into new environments have been of intensive research topic in freshwater ecology, the genetic structures of freshwater Corbicula in its native range remain poorly understood. In this study, the genetic structures of two Korean freshwater Corbicula clonal lineages were characterized by cross-referencing the nuclear genomic structures with mtDNA sequence analysis. In spite of substantial genetic differences (Nei's D = 0.363-0.372) and a pronounced level of fixed allelic distinctions (in six of 20 allozyme loci) between Corbicula lineages, no lineage-specific mtDNA differentiation was observed. The evident disjunction between mtDNA sequences and nuclear genomes is a compelling evidence for the existence of interspecific nuclear hybrid genome structures, comprising different combinations of paternal and maternal contributions. This unusual novel finding is the first case demonstrating that morphologically and allozymatically distinct, yet mitochondrially identical clonal lineages exist in the genus Corbicula. However, we could not find the ancestral species for these two clonal lineages in the present study, and the answer for this question must wait until the genetic structure of Asian Corbicula taxa is fully characterized.

Animals↗
PubMed2002

Intragenomic length variation of the ribosomal DNA intergenic spacer in a malaria vector, Anopheles sinensis.

We determined the complete sequences of six size variants of intergenic spacer (IGS) region from one individual of the malaria vector mosquito species, Anopheles sinensis. All six size variants observed in this study show almost the same basic primary structure in which three repeat regions (A, B, and C) are interspersed by highly conserved nonrepeating sections. In contrast to the well-ordered subrepeating patterns found in A and C, the repeat region B displays extremely variable and complicated profiles in the number and arrangement of subrepeat units among different size classes. It is apparent that the prominent level of length difference in the repeat regions B and C is responsible for the intragenomic length variations of the IGS molecule observed in the present study. High level of sequence homology and regularly arranged repeating pattern of 11 to 14 bp motif sequences harbored within the B repeat region allow us to consider that these motif sequences may be associated with their potential role as a recombination site. Compared to those previously published in other mosquito species, the IGS of A. sinensis showed a very unique structural format in subrepeat patterns of the IGS region. This result suggests that the structure and sequence profiles of the IGS region would provide useful information for the exploitation of a convenient molecular marker to identify morphologically complicated species complex and to characterize the genetic variation of population. This suggestion is far from being conclusive at present, but a further genetic study will bring more compelling evidences for this pending issue.

Animals↗
PubMed2002

Proteome analysis of hepatocellular carcinoma.

Development of hepatocellular carcinoma (HCC) is a complex process involving multiple changes in gene expression and usually occurs in the presence of liver cirrhosis. In this research, we observed proteome alterations of three tissue types isolated from livers of HCC patients: normal, cirrhotic, and tumorous tissue. Proteome alterations were observed using two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Comparing the tissue types with each other, a significant change in expression level was found in 21 proteins. Of these proteins, sarcosine dehydrogenase, liver carboxylesterase, peptidyl-prolyl isomerase A, and lamin B1 are considered novel HCC marker candidates. In particular, lamin B1 may be considered as a marker for cirrhosis, because its expression level changes considerably in cirrhotic tissue compared with normal tissue. The proteins revealed in this experiment can be used in the future for studies pertaining to hepatocarcinogenesis, or as diagnostic markers and therapeutic targets for HCC.

Biomarkers, Tumor↗
PubMed2002

Protective effect of adrenomedullin in mannitol-induced apoptosis.

Mannitol therapy is widely used for reducing brain edema, and ischemic brain swelling. However, mannitol at clinical concentrations induces apoptosis in endothelial cells. Because apoptosis may be a pathogenic mechanism in vascular injury, antiapoptotic agents may have a protective role in mannitol-induced apoptosis. In this study, we examined whether adrenomedullin (AM) prevents mannitol-induced apoptosis and also evaluated the associated signaling pathway of AM in human umbilical vein endothelial cells. AM prevented mannitol-induced apoptosis in a dose-dependent manner. Pretreatment with wortmannin blocked the AM-induced antiapoptotic effect. AM stimulated Akt at Ser473, and wortmannin inhibited the AM-induced Akt phosphorylation. These findings indicate that phosphatidylinositol 3'-kinase/Akt pathway transmits the survival signal from AM. The potency of antiapoptotic effect of AM is stronger than that of vascular endothelial growth factor and angiopoietin-1 in mannitol-induced apoptosis. AM can have a protective role not only in umbilical vein, but also in pulmonary, coronary, and aortic endothelial cells. These findings indicate that AM has a potent protective role in mannitol-induced apoptosis, through phosphatidylinositol 3'-kinase/Akt pathway. Therefore, pretreatment with AM might help to maintain normal endothelial integrity during systemic mannitol therapy.

Adrenomedullin↗
PubMed2002

Pathogenesis and treatment of hypernatremia.

Two aspects of hypernatremia are emphasized in this discussion: pathogenesis and treatment. Hypernatremia rarely develops with increased water loss alone; there must be a mechanism that interferes with water intake. In treating hypernatremia, the speed of correction is important because the volume regulation mechanisms restore the brain volume to normal when hypernatremia is chronic. Thus, too rapid correction of chronic hypernatremia results in brain edema. The calculation of fluid volume needed to correct hypernatremia can be obtained with use of various formulae described here for the fluid that contains dextrose in water or for hypotonic saline solution. Accurate prediction of the fluid volume requirement demands the knowledge of urine output and its electrolyte content, but when the information is not available, urine may be assumed to be isotonic in its electrolyte content.

Body Water↗
PubMed2002

DNA splice site detection: a comparison of specific and general methods.

In an era when whole organism genomes are being routinely sequenced, the problem of gene finding has become a key issue on the road to understanding. For eukaryotic organisms a large part of locating the genes is accomplished by predicting the likely location of splice sites on a DNA strand. This problem of splice site location has been ap- proached using a number of machine learning or statistical methods tailored more or less specifically to the nature of the problem. Recently large margin classifiers and boosting methods have been found to give improvements over more traditional methods in a number of areas. Here we compare large margin classifiers (SVM and CMLS) and boosted decision trees with the three most common models used for splice site detection (WMM, WAM, and MDT). We find that the newer methods compare favorably in all cases and can yield significant improvement in some cases.

Algorithms↗
PubMedDate not supplied

Outcome of endovascular treatment in symptomatic intracranial vascular stenosis.

OBJECTIVE: The outcome evaluation for the revascularization of intracranial vascular stenoses has not been fully described due to the highly technical nature of the procedure. We report here on the early and late clinical outcomes of angioplasty and/or stenting of symptomatic severe intracranial vascular stenoses at a single institute. MATERIALS AND METHODS: Since 1995, we have treated 35 patients with symptomatic intracranial vascular stenosis (more than 70% stenosis, mean stenosis: 78.6%+/-6.2%). Angioplasty (n = 19) was performed for the horizontal segment of the middle cerebral artery (M1) (n = 16) and the basilar artery (BA) (n = 1), the intradural vertebral artery (VA) (n = 1), and the cavernous internal carotid artery (ICA) (n = 1). Stenting (n = 16) was performed for the cavernous or petrous ICAs (n = 9), the intradural VA (n = 3), BA (n = 2), and M1 (n = 2) artery. We assessed the angiographic success (defined as residual stenosis < 50%) rate, the periprocedural complications during the 30-day periprocedural period, the symptomatic recurrence and restenosis during a mean 22-month follow-up (FU) period. The Kaplan-Meier estimate of the cumulative event-free rate of the major cerebrovascular events, i.e. death, stroke or restenosis, was also done. RESULTS: Angiographic success was achieved in 97% of our patients (34/35). There were four procedure-related complications (11%) including a death and a minor stroke. During the mean 22-month FU, the asymptomatic restenosis rate was 9% and the symptomatic restenosis rate was 6% in the target lesion and 9% in all the vascular territories. The Kaplan-Meier estimate was 70.6% (95% confidence interval = 46.5-94.7) after 33 months of FU. CONCLUSION: In addition to a high angiographic success rate and an acceptable periprocedural complication rate, intracranial angioplasty and/or stenting revealed a relatively low symptomatic recurrence rate. Hemorrhage is a rare, but the physician must aware that potentially fatal periprocedural complications can occur.

Adult↗