Hyuk-Joon Kwon

Clinical and Histological Effect of a Low Glycaemic Load Diet in Treatment of Acne Vulgaris in Korean Patients: A Randomized, Controlled Trial

Recent studies have suggested that dietary factors, specifically glycaemic load, may be involved in the pathogenesis of acne. The aim of this study was to determine the clinical and histological effects on acne lesions of a low glycaemic load diet. A total of 32 patients with mild to moderate acne were randomly assigned to either a low glycaemic load diet or a control group diet, and completed a 10-week, parallel dietary intervention trial. Results indicate successful lowering of the glycaemic load. Subjects within the low glycaemic group demonstrated significant clinical improvement in the number of both non-inflammatory and inflammatory acne lesions. Histopathological examination of skin samples revealed several characteristics, including reduced size of sebaceous glands, decreased inflammation, and reduced expression of sterol regulatory element-binding protein-1, and interleukin-8 in the low glycaemic load group. A reduction in glycaemic load of the diet for 10 weeks resulted in improvements in acne.

Establishment and characterization of 12 human colorectal-carcinoma cell lines

In this article, we describe the characteristics of 12 human colorectal‐carcinoma cell lines established from 6 primary tumors and 6 metastatic sites of 11 Korean colorectal‐carcinoma patients, including the morphology in vivo and in vitro and mutations of K‐ras2, p15, p16, p53, APC, β‐catenin, hMLH1 and hMSH2 genes in vitro. No lines were contaminated with Mycoplasma or bacteria. All lines were proven to be unique by DNA‐fingerprinting analysis. All lines expressed the surface carcino‐embryonic antigen and secreted it into the supernatant fluid. The morphological correlation between the original tumors and cultured cells suggested that the original tumors showing mucinous adenocarcinoma correlated with floating aggregates in culture, and degree of desmoplasia in the original tumor correlated with attached growth in culture. Five of the cell lines showed mutations in the K‐ras2 gene, and 6 of the cell lines showed mutations in the p53 gene. The p15 gene was deleted in 2 cell lines, and the p16 gene was hypermethylated in 3 cell lines. The mutation of mismatch‐repair genes (hMLH1 and hMSH2) was found in 4 lines, the APC gene and β‐catenin gene were mutated in 9 and 2 lines respectively. These well‐characterized colorectal‐cancer cell lines should serve as useful tools for investigating the biological characteristics of colorectal cancer. Int. J. Cancer 81:902–910, 1999.

Differentiation of Salmonella enterica serotype gallinarum biotype pullorum from biotype gallinarum by analysis of phase 1 flagellin C gene (fliC).

Salmonella enterica serotype gallinarum biotype gallinarum and biotype pullorum are non-motile and pathogenic avian strains. Biotype gallinarum causes fowl typhoid and biotype pullorum is the cause of pullorum disease in chickens. The two biotypes could be differentiated based on biochemical characteristics. However, conventional culture and biochemical assays are time-consuming, laborious and need sterile laboratory practices. Although the two biotypes, gallinarum and pullorum are non-motile, they possess the phase 1 flagellin C gene. The variable regions of the flagellin C gene from 41 biotype pullorum and 52 biotype gallinarum were amplified by colony-PCR and analyzed by single strand conformational polymorphism (SSCP) method. Differences in SSCP electrophoretic patterns were confirmed by nucleotide sequencing. In addition, PCR-RFLP with Hinp1I was also successfully applied to differentiate the two biotypes. These results suggested that the variable regions of fliC could be used as a genetic marker to differentiate biotype gallinarum from biotype pullorum.

The clinical and histological effect of home‐use, combination blue–red LED phototherapy for mild‐to‐moderate acne vulgaris in Korean patients: a double‐blind, randomized controlled trial

Background  Blue and red light have been reported to have beneficial effects on acne. However, there has been no double‐blind, randomized study of acne treatment for combined blue and red light‐emitting diode (LED) devices, and the associated molecular mechanisms have rarely been investigated.

Molecular epidemiology of Newcastle disease in Republic of Korea

Twenty-three strains of Newcastle disease virus (NDV) isolated between 1988 and 1999 in Republic of Korea were studied by partial nucleotide sequencing of fusion (F) gene and phylogenetic analysis. Most of Korean strains formed a distinctive cluster in genotype VI and they were genetically distant (4.0-8.7%) from other subtypes (a, b, c, d, and e), and termed provisionally VIf. Some Korean strains isolated in 1995 were grouped into genotype VIIa and they were closer to Taiwan strains than western Europe. The results suggest that the genotype VIf strains have been maintained by enzootic infections during the past decade, while genotype VIIa appears to be introduced more recently in Republic of Korea.

What's new in the physiopathology of acne?

There are four central factors that contribute to acne physiopathology: the inflammatory response, colonization with Propionibacterium acnes, increased sebum production and hypercornification of the pilosebaceous duct. In addition, research in the areas of diet and nutrition, genetics and oxidative stress is also yielding some interesting insights into the development of acne. In this paper we review some of the most recent research and novel concepts revealed in this work, which has been published by researchers from diverse academic disciplines including dermatology, immunology, microbiology and endocrinology. We discuss the implications of their findings (particularly in terms of opportunities to develop new therapies), highlight interrelationships between these novel factors that could contribute to the pathology of acne, and indicate where gaps in our understanding still exist.

Anti-influenza diarylheptanoids from the bark of Alnus japonica

This study to investigate anti-influenza components from the bark of Alnus japonica resulted in the isolation of two rare acylated diarylheptanoids, named oregonoyl A (5) and oregonoyl B (6), along with nine known compounds (1-4 and 7-11). Their structures were elucidated on the basis of extensive spectroscopic and chemical methods. Antiviral testing of compounds 1-11 against KBNP-0028 (H9N2) avian influenza virus showed that platyphyllone (10) was strongly active, and platyphyllonol-5-xylopyranoside (9) was moderately active against KBNP-0028 as compared with the positive control, zanamivir, respectively.

Chronological Study of Antibiotic Resistances and Their Relevant Genes in Korean Avian Pathogenic Escherichia coli Isolates

ABSTRACT Antibiograms and relevant genotypes of Korean avian pathogenic Escherichia coli (APEC) isolates (n = 101) recovered between 1985 and 2005 were assessed via disc diffusion test, PCR, restriction enzyme analysis, and sequencing. These isolates were highly resistant to tetracycline (84.2%), streptomycin (84.2%), enrofloxacin (71.3%), and ampicillin (67.3%), and most of the tetracycline, streptomycin, enrofloxacin, and ampicillin resistances were associated with tetA and/or tetB, aadA and/or strA-strB, mutations in gyrA and/or parC, and TEM, respectively. Class 1 integrons were detected in 40 isolates (39.6%), and a variety of gene cassettes conferring streptomycin (aadA), gentamicin (aadB), and trimethoprim (dfr) resistances were identified: aadA1a (27.5%), dfrV-orfD (2.5%), aadB-aadA1a (2.5%), dfrI-aadA1a (47.5%), dfrXVII-aadA5 (12.5%), and dfrXII-orfF-aadA2 (7.5%). In addition, several types of common promoters (Pant) of the gene cassettes (hybrid P1, weak P1, or weak P1 plus P2) and single-nucleotide polymorphisms in aadA1a were identified. The results of a chronological analysis demonstrated significant and continuous increases in the frequencies of resistances to several antibiotics (tetracycline, streptomycin, enrofloxacin, ampicillin, and trimethoprim-sulfamethoxazole) and of the relevant resistance genes (tetA, strA-strB, and TEM), mutations in gyrA and parC, and multidrug-resistant APEC strains during the period 2000 to 2005.

Variation of a Newcastle Disease Virus Hemagglutinin-Neuraminidase Linear Epitope

ABSTRACT Fifty-six Newcastle disease virus strains collected from 2000 to 2006 could be grouped into subgenotype VIId. However, they displayed cumulative mutations in and around the linear epitope of hemagglutinin-neuraminidase (residues 345 to 353) with time. The antigenicities of the variants that became predominant in Korea differ from each other and from the wild type.

Pathogenicity of SG 9R, a rough vaccine strain against fowl typhoid.

SG 9R, a rough vaccine strain of Salmonella gallinarum, has been used for the prevention of fowl typhoid and paratyphoid in the world despite the presence of residual virulence. SG 9R-like rough strains have been recently isolated from fowl typhoid cases; however, molecular markers to differentiate SG 9R from field strains are not well-characterized and the molecular mechanisms of SG 9R residual virulence are unclear. Therefore, we analyzed LPS biosynthesis (rfa gene cluster) and virulence genes (spv, SPI-2) of both SG 9R and S. gallinarum rough field strains. SG 9R carried a unique nonsense mutation in rfaJ (TCA to TAA) and a shared rfaZ mutation (G-deletion) by rough and smooth S. gallinarum strains. SG 9R also carried intact SPI-2 and spvC, B, A, and R (except deleted spvD). SG 9R-like rough strains (n=10) carried identical mutations in virulence-related genes to SG 9R. SG 9R and SG 9R-like rough strains did not demonstrate significant mortality or liver lesions under normal conditions. However, fowl typhoid was successfully reproduced in the present study by SG 9R inoculation to 1-day-old male brown layer chicks per os following starvation. Therefore, the LPS defect may be one of the major mechanisms of SG 9R attenuation, and the possession of intact SPI-2, spvC, B, A, and R virulence genes may be associated with residual SG 9R virulence.