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Hyun-Joo Kim

Publications and source records attributed to Hyun-Joo Kim.

16 recordsLinked to original sources
PubMed2025

Identification of circulating miRNA alterations in diabetes patients excluding periodontitis effects: insights into target gene downregulation in diabetic complications.

BACKGROUND: Diabetes mellitus (DM) induces systemic complications through chronic metabolic dysregulation. Circulating exosomal microRNAs (miRNAs) are emerging as key regulators of post-transcriptional gene expression and may drive diabetes-associated pathologies. Although miRNAs have been widely studied in diabetes, the characterization of PD-independent miRNA signatures across tissues remains limited. This study aimed to identify DM-specific miRNA alterations and their contribution to systemic metabolic dysfunction independent of PD. METHODS: Exosomes were isolated from plasma samples, and small RNA sequencing was performed to identify differentially expressed miRNAs (DE-miRs) using the limma R package. Predicted target genes were identified using TargetScan and validated through bulk RNA sequencing datasets from four tissues-foot, kidney, pancreas, and retina. Differentially expressed genes (DEGs) were analyzed, followed by Gene Ontology Biological Process (GOBP) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment to elucidate diabetes-related mechanisms. RESULTS: We identified 9 upregulated and 6 downregulated DE-miRs specific to the diabetic group. TargetScan predicted 216 upregulated and 64 downregulated target genes. Functional validation revealed that these genes were enriched in pathways related to glucose metabolism, cellular stress response, and tissue repair. Notably, SREK1 and GLIPR1 were commonly detected across all four tissues, suggesting potential systemic regulators of diabetes-related complications. CONCLUSION: This study suggests that circulating exosomal miRNAs, independent of periodontitis, may function as systemic regulators in diabetes. Unlike previous studies, which did not distinguish co-morbid periodontitis, we specifically defined PD-independent miRNA signatures and validated their cross-organ regulatory effects on target genes. Our results revealed a cross-organ miRNA-mRNA regulatory network and identified common regulatory targets. These findings provide insights into both systemic and organ-specific mechanisms underlying diabetic complications and highlight the potential of miRNAs as biomarkers and therapeutic targets.

Humans↗
PubMed2006

Hollow-fiber flow/hyperlayer field-flow fractionation for the size characterization of airborne particle fractions obtained by SPLITT fractionation.

Hollow-fiber flow field-flow fractionation (HF FlFFF) was applied for the separation and size characterization of airborne particles which were collected in a municipal area and prefractionated into four different-diameter intervals >5.0, 2.5-5.0, 1.5-2.5, <1.5 microm) by continuous split-flow thin (SPLIIT) fractionation. Experiments demonstrated the possibility of utilizing a hollow-fiber module for the high-performance separation of supramicron-sized airborne particles at steric/hyperlayer operating mode of HF FlFFF. Eluting particles during HF FlFFF separation were collected at short time intervals (approximately 10 s) for the microscopic examination. It showed that particle size and size distributions of all SPLITT fractions of airborne particles can be readily obtained using a calibration and that HF FlFFF can be utilized for the size confirmation of the sorted particle fraction during SPLITT fractionation.

Journal Article↗
PubMed2006

Prediction of transmural extent of infarction with contrast echocardiographically derived index of myocardial blood flow and myocardial blood volume fraction: comparison with contrast-enhanced magnetic resonance imaging.

BACKGROUND: We sought to determine the accuracy of myocardial contrast echocardiography (MCE)-derived index of myocardial blood flow and myocardial blood volume fraction (MBVF) in predicting transmural extent of infarction and wall-motion recovery. METHODS: Low and high mechanical index MCE and contrast-enhanced magnetic resonance imaging were performed 5 to 7 days after successful percutaneous revascularization in 30 patients with acute myocardial infarction and regional wall-motion change was assessed 3 months later. The index of myocardial blood flow was calculated as A x beta (dB/s) using the equation y = A (1 - e(-beta t)), which fits the replenishment curve of low mechanical index MCE. The MBVF (mL/100 g myocardium) was calculated as 100 x 10(relative contrast intensity [CI]/10), using the relative CI by subtracting the cavity CI from the adjacent transmural CI using high mechanical index MCE. The contrast-enhanced magnetic resonance imaging-derived transmural extent of delayed hyperenhancement (DE) in 16 segments were measured and compared with corresponding MCE data. RESULTS: Among 480 segments, 382 measurable segments were subdivided into 5 groups as follows: no DE, 1% to 25% DE, 26% to 50% DE, 51% to 75% DE, and 76% to 100% DE. An increment of the extent of DE was significantly related to a decrement of A x beta (P < .001) and MBVF (P < .001). The optimal cut-off MBVF for predicting greater than 50% DE was 1.92 mL (sensitivity 82%, specificity 73%, P < .01), and persistently dysfunctional motion was 1.81 mL (sensitivity 74%, specificity 75%, P < .01). CONCLUSION: The MCE-derived A x beta and MBVF can be effective predictors of transmural extent of infarction and wall-motion recovery in the reperfused acute myocardial infarction.

Blood Flow Velocity↗
PubMed2006

In vitro and in vivo antibacterial activities of DW-224a, a new fluoronaphthyridone.

DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

Animals↗
PubMed2005

Cyclic topology in complex networks.

We introduce a cyclic coefficient R which characterizes the degree of circulation in complex networks. If a network has a perfect treelike structure, then R becomes zero. The larger value of R represents that the network has more cyclic structure. We measure both the cyclic coefficients and the distributions of local cyclic coefficients for various networks and discuss the cyclic structures of them.

Journal Article↗
PubMed2005

Pinched inlet gravitational split-flow thin fractionation of airborne particles and analysis of size dependent level of PCDD/Fs.

Fine particles in air have a direct influence on human health because they carry toxic chemicals that can be deposited in the human lung when inhaled. Thus, particle size distribution and size dependent level of contamination of the airborne particles are important parameters for the study and assessment of environmental pollution. In this study, gravitational split-flow thin (SPLITT) fractionation (or GSF), a semi-preparative scale separation technique for particles, was applied for the continuous size sorting of airborne particles collected in urban area. About 2.0 g of airborne particles was fractionated into four different size intervals (<1.5, 1.5-2.5, 2.5-5.0, and >5.0 microm), and the collected fractions were examined by electron microscopy for particle size distribution and analyzed for the size dependent levels of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs). It was found that more than 60% of particles including dissolved matters in weight were smaller than 5.0 microm and they contained more than 86% of the total PCDD/Fs amount in airborne particles.

Benzofurans↗
PubMed2005

MTHFR C677T polymorphism associates with unexplained infertile male factors.

PURPOSE: To determine whether 5,10-methylenetetrahydrofolate reductase (MTHFR C677T and A1298C) genotype is associated with male infertility. METHODS: Analysis of cytogenetic, Y chromosomal microdeletion assay (Yq), and the C677T and A1298C polymorphisms of the MTHFR gene by pyrosequencing and PCR-Restriction Fragment Length Polymorphism (RFLP) method. SAS 8.1 assessed the statistical risk of MTHFR genotype. RESULTS: The homozygous (T/T) C677T polymorphism of the MTHFR gene was present at a statistically high significance in unexplained infertile men with normal karyotype, instead at no significance in explained infertile men with chromosomal abnormality or Y chromosome deletion. There was no statistically significance of A1298C variation in infertile males. CONCLUSIONS: The MTHFR 677TT genotype may be a genetic risk factor for male infertility, especially with severe OAT and non-obstructive azoospermia in unexplained infertile males.

Chromosomes, Human, Y↗
PubMed2005

Model averaging using the Kullback information criterion in estimating effective doses for microbial infection and illness.

Since the National Food Safety Initiative of 1997, risk assessment has been an important issue in food safety areas. Microbial risk assessment is a systematic process for describing and quantifying a potential to cause adverse health effects associated with exposure to microorganisms. Various dose-response models for estimating microbial risks have been investigated. We have considered four two-parameter models and four three-parameter models in order to evaluate variability among the models for microbial risk assessment using infectivity and illness data from studies with human volunteers exposed to a variety of microbial pathogens. Model variability is measured in terms of estimated ED01s and ED10s, with the view that these effective dose levels correspond to the lower and upper limits of the 1% to 10% risk range generally recommended for establishing benchmark doses in risk assessment. Parameters of the statistical models are estimated using the maximum likelihood method. In this article a weighted average of effective dose estimates from eight two- and three-parameter dose-response models, with weights determined by the Kullback information criterion, is proposed to address model uncertainties in microbial risk assessment. The proposed procedures for incorporating model uncertainties and making inferences are illustrated with human infection/illness dose-response data sets.

Food Microbiology↗
PubMed2004

Pinched inlet split flow thin fractionation for continuous particle fractionation: application to marine sediments for size-dependent analysis of PCDD/Fs and metals.

It is demonstrated that split-flow thin (SPLITT) fractionation, a continuous separation technique for sorting particles or macromolecules, can be utilized for the fractionation of environmental particles to study a size-dependent analysis of pollutants. In this study, focuses are made on the use of a pinched inlet gravitational SPLITT fractionation, a modified form of SPLITT channel formed by reducing the sample inlet thickness of the channel to improve separation efficiency, to separate marine sediments into five different sizes (<1.0, approximately 1.0 to 2.5, approximately 2.5 to 5.0, approximately 5.0 to 10, and approximately 10 to 53 microm). The resulting size fractions are examined with high resolution gas chromatography/high resolution mass spectrometry to determine the size-dependent distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans along with a statistical data treatment and are analyzed with inductively coupled plasma-atomic emission spectrometry and graphite furnace atomic absorption spectrometry to ascertain its major and trace metals. It is shown that the combined analytical methods detailed in this study can be powerfully utilized in such a way as to analyze pollutant distribution and its concentration with regard to particle sizes for an environmental assessment.

Chemical Fractionation↗
PubMed2003

Genetic analysis of three polymorphic sites of the luteinizing hormone beta-subunit gene in infertile Korean men with nonobstructive azoospermia.

OBJECTIVE: To investigate the genetic background of nonobstructive male factor infertility. DESIGN: Clinical and controlled study. PATIENT(S): Ninety-five nonobstructive male infertile patients (75 with azoospermia, 18 with oligoasthenoteratozoospermia, and two with oligozoospermia) and 200 healthy fertile control men. INTERVENTION(S): Patients were investigated for genetic background including karyotype, Yq chromosome deletion, and three polymorphisms of the LH beta-subunit gene (Trp8Arg, Ile15Thr, and Gly102Ser). MAIN OUTCOME MEASURE(S): To determine three polymorphisms of the LH beta-subunit gene. RESULT(S): An abnormal karyotype was found in 11 of the 75 patients with azoospermia and one of the 18 patients with oligoasthenoteratozoospermia. Eleven (12%) had one or more deleted sites at 13 loci on Yq. The Gly102Ser variant of the LH beta-subunit gene was not detected at all. The frequency of double Trp8Arg and Ile15Thr heterozygotes was similar between the fertile (14.5%, n = 200) and infertile (12.6%, n = 95) groups, with the exception of one homozygous mutation (Arg8 and Thr15) from patient with azoospermia. CONCLUSION(S): Three variants of the LH beta-subunit gene (Trp8Arg, Ile15Thr, and Gly102Ser) may not be associated with male factor infertility. We found one homozygous Arg8 and Thr15 mutation in a patient with azoospermia with normal hormone levels (FSH, LH, PRL, T), a normal karyotype, and no Yq microdeletions.

Adult↗
PubMed2003

Molecular and cytogenetic characterization of two azoospermic patients with X-autosome translocation.

PURPOSE: To report two azoospermic patients with reciprocal X-autosome translocations. METHODS: Cytogenetic analysis utilizing GTG-banding and Yq microdeletions shown by polymerase chain reaction (PCR) with 12 sequence-tagged site (STS) markers for Y chromosome microdeletions. RESULTS: Cytogenetic analysis showed one man with 46,Y,t(X;19)(q22;q13.3) and the other with 46,Y,t(X;8)(p22;q11). Neither had any Yq microdeletions shown. The patient with 46,Y, t(X;8)(p22;q11) showed a slightly lower than normal testosterone level. By NCBI-Blast search, we found four testis-specific genes, t-complex-associated-testis-expressed 1-like (TCTE1L), Ferritin, heavy polypeptide-like 17 (FTHL17), Testis expressed sequence 13A (TEX13A), and Testis expressed sequence 13B (TEX13B) located near breakpoints on X chromosome. FTHL17, TEX13A, and TEX13B are spermatogonially-expressed, germ-cell-specific genes. CONCLUSION: This is the first clinical report of azoospermia with reciprocal X-autosome translocations on Xp22 and q22. These translocations on Xp22 and q22 may be direct genetic risk factors for azoospermia.

Adult↗
PubMed2002

Self-organized interface growth with the negative nonlinearity in a random medium.

We introduce two self-organized growth models that describe the motion of the driven interfaces in random media including the Kardar-Parisi-Zhang (KPZ) nonlinearity. One model follows the quenched KPZ equation with a positive nonlinear term, while the other model follows the quenched KPZ equation with a negative nonlinear term. By obtaining the critical exponents for two models, we confirm that the sign of the KPZ nonlinear term does not affect the universality class.

Journal Article↗
PubMed2002

The effect of combination treatment of the recalcitrant pigmentary disorders with pigmented laser and chemical peeling.

BACKGROUND: The pigmentary disorders including melasma, freckles, postinflammatory hyperpigmentation, or acquired bilateral nevus of Ota-like macules, etc. are usually resistant to all treatment modalities, and are therefore very frustrating to the patient and clinician. OBJECTIVE: The purpose of this study was to demonstrate the effect of the combination treatment of recalcitrant pigmentary disorders with pigmented laser and chemical peeling and to observe any side-effects. METHODS: Twenty-four patients with recalcitrant facial pigmentary disorders were treated with the Q-switched alexandrite laser at fluences of 7.0-8.0 J/cm2 or the pigmented lesion dye laser (PLDL) at fluences of 2.0-2.5 J/cm2, and at the same session, 15-25% trichloroactic acid (TCA) with or without Jessner's solution were used for the chemical peeling. And the results were clinically analyzed. RESULTS: In the assessment by the patients, 63% of them considered the result as "clear, excellent, or good" in respect to the color and 54% of them assessed that the size of the lesion had cleared more than 50%. In the assessment by a clinician, 67% of the patients were categorized into the grade of clear, excellent, or good. There were no significant complications with this combination method. CONCLUSIONS: The combination treatment with pigmented laser and chemical peeling is effective, safe, and relatively inexpensive treatment modalities in the recalcitrant pigmentary disorders.

Adult↗
PubMed2001

Stochastic growth models for driven interfaces through random media in two and three dimensions.

We introduce two simple stochastic growth models which describe the motion of the interfaces driven through random media in two and three dimensions. One model describes the motion of the interface driven through isotropic random media, where the dynamics of the interface can be described by the quenched Edwards-Wilkinson (QEW) equation. The other model describes the motion of the interface driven through anisotropic random media, where the dynamics of the interface can be described by the quenched Kardar-Parisi-Zhang (QKPZ) equation. We show via computer simulations that two models belong to the QEW and QKPZ universality class in two and three dimensions, respectively.

Journal Article↗