Publications by authors named "Hong-ran Choi"

Porphyromonas gingivalis causes chronic inflammatory diseases (periodontal diseases) that destroy the periodontal ligament and alveolar bone. Antimicrobial peptides are crucial components of the host defense response required to maintain cellular homeostasis during microbial invasion. Because light-emitting diode (LED) irradiation influences the host defense response against bacterial infections, we investigated its effect on immortalized gingival fibroblasts (IGFs) infected with P.

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Objective: The purpose of this study was to evaluate the relationship of 625, 525, and 425 nm wavelengths, providing average power output and effects on three common pathogenic bacteria.

Background Data: Ultraviolet (UV) light kills bacteria, but the bactericidal effects of UV may not be unique, as 425 nm produces a similar effect. The bactericidal effects of light-emitting diode (LED) wavelengths such as 625 and 525 nm have not been described.

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Purpose: At present, information regarding periodontal disease in geriatric patients is scarce. The purpose of this study was to quantify the periodontal pathogens present in the saliva of Korean geriatric patients and assess the relationship between the bacterial levels and the periodontal condition.

Methods: Six putative periodontal pathogens were quantified by using a real-time polymerase chain reaction assay in geriatric patient groups (>60 years) with mild chronic periodontitis (MCP), moderate chronic periodontitis (MoCP), and severe chronic periodontitis (SCP).

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Heat shock protein-27 (HSP27) is a member of the small HSP family which has been linked to the nuclear factor-kappa B (NF-κB) signaling pathway regulating inflammatory responses. Clinical reports have suggested that low-level light therapy/laser irradiation (LLLT) could be an effective alternative treatment to relieve inflammation during bacterial infection associated with periodontal disease. However, it remains unclear how light irradiation can modulate the NF-κB signaling pathway.

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Objective: The aim of this study was to examine the reactive oxygen species (ROS) that are dissipated by 635 nm irradiation, and the effect of 635 nm irradiation on ROS scavenging system.

Background Data: Intracellular ROS are produced in the form of superoxide anion by either nicotinamide adenine dinucleotide phosphate (NADPH) oxidase or xanthine oxidase in response to a number of stimuli. Low-level light irradiation decreases the intracellular ROS level and has been used in clinical situations for reducing the level of oxidative stress.

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Hyperglycemia occurs in patients with poorly controlled diabetes mellitus and contributes to bone resorption and increased susceptibility to bacterial infections. Hyperglycemia can incite low-grade inflammation that can contribute to the resorption of bone, especially the periodontal bone. The increased susceptibility to periodontal infections can contribute to bone resorption through the activation of osteoclasts.

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Human gingival fibroblasts (hGFs) play an important role in the inflammatory reaction to lipopolysaccharide (LPS) from P. gingivalis, which infects periodontal connective tissue. In addition, although light-emitting diode (LED) irradiation has been reported to have biostimulatory effects, including anti-inflammatory activity, the pathological mechanisms of these effects are unclear.

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Background And Objectives: It is recognized that hypoxic/ischemic conditions leading to production of reactive oxygen species (ROS) are an important mediator of angiogenesis in the wound-healing process. Recently, low level light irradiation at 635 nm, which is used in many clinical fields, was found to decrease intracellular ROS levels, and consequently alleviate oxidative stress. The purpose of the present study was to investigate the effects of 635 nm light-emitting diode (LED) irradiation on angiogenesis in human umbilical vein endothelial cells, in an in vitro CoCl(2) -induced severe hypoxia model.

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Context: A growing body of evidence shows that compounds of plant origin have the ability to prevent cancer. The fruit of gardenia, Gardenia jasminoides Ellis (Rubiaceae), has long been used as a food additive and herbal medicine, and its pharmacological actions, such as protective activity against oxidative damage, cytotoxic effect, and anti-inflammatory and anti-tumor activity, have already been reported.

Objective: The purpose of the present study was to investigate the presence of DNA topoisomerase 1 inhibitor in various solvent fractions of Gardenia extract and examine the induction of oral cancer cell death upon treatment with Gardenia extract.

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An oncocytic mucoepidermoid carcinoma arising from the minor salivary gland origin is extremely rare. We report on a 44-year-old man with a high-grade oncocytic mucoepidermoid carcinoma originating in the minor salivary gland of the posterior mandible. All tumor cells showed the expected pattern of immunoreactivity, with positive results for the antimitochondrial antibody and p63, and negative results for the androgenic receptor antibody.

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Nitric oxide (NO) is a major factor contributing to the loss of neurons in ischemic stroke, demyelinating diseases, and other neurodegenerative disorders. NO not only functions as a direct neurotoxin, but also combines with superoxide (O(2)(-)) by a diffusion-controlled reaction to form peroxynitrite (ONOO(-)), a species that contributes to oxidative signaling and cellular apoptosis. However, the mechanism by which ONOO(-) induces apoptosis remains unclear, although subsequent formation of reactive oxygen species (ROS) has been suggested.

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Estrogen receptor-related receptor gamma (ERRgamma/ERR3/NR3B3) is a member of the orphan nuclear receptor with important functions in development and homeostasis. Recently it has been reported that ERRalpha is involved in osteoblast differentiation and bone formation. In the present study we examined the role of ERRgamma in osteoblast differentiation.

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Glycyrrhiza uralensis (Leguminosae) has long been known as an antiinflammatory agent for gastric ulcers, arthritis, and rheumatism. The flavonoid glycyrol (GC) (10 microg/ml) isolated from G. uralensis dramatically inhibits phorbol ester (phorbol 12-myristate 13-acetate)-induced nuclear factor (NF)-kappaB-dependent transcriptional activity, as determined by luciferase reporter activity in human kidney epithelial 293T cells.

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To investigate, for the first time, the events associated with the phenotypic and clinical diversities of head and neck squamous carcinomas (HNSC), we performed molecular analyses on 92 primary tumors representing the entire spectrum of the morphologic subtypes using microsatellite markers at chromosome 3p, 4p, 8p, 9p, 11q, 17p, and 18q regions and correlated the results with the clinicopathologic features and patients' survival. Loss of heterozygosity (LOH) at D9S168 and D9S171 markers on chromosome 9p regions was commonly identified in all subtypes. Distinctive alterations in certain subtypes were noted at chromosomes 3p, 4p, 8p, and 11p regions.

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Adenocarcinomas of nonsalivary origin represent approximately 10% to 20% of all sinonasal malignancies and are characterized by varying histopathologic features and uncertain histogenesis. To better understand the histogenesis and phenotypic heterogeneity of these tumors, we performed immunohistochemical analyses for cytokeratin (CK) 7 and CK20 on 12 primary sinonasal adenocarcinomas (SNACs) representing the histopathologic spectrum of these tumors, adjacent normal mucosa, and 2 metastatic adenocarcinomas from colonic primaries. The demographic and clinicopathologic characteristics of our cohort were similar to those in previously published series.

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The underlying events associated with the development of sarcomatoid head and neck squamous carcinoma and the biologic significance remain unknown. To investigate the genetic events involved in the evolution of this entity, comparative analysis of matched microdissected epithelial and sarcoma-like components from 11 primary sarcomatoid carcinomas was performed using microsatellite markers. Nine markers on chromosomes 4p, 9p, and 17p regions (3 per each chromosomal region) were selected based on their informativeness, small product size, and the high alterations in head and neck squamous carcinomas.

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The cyclin-dependent kinase inhibitors p27Kip1 and p21WAF1/Cip1 play important roles in cell-cycle regulation. Although alterations of these genes have been linked to tumorigenesis of several human carcinomas, their involvement in head and neck squamous tumorigenesis is rarely investigated. To determine the role of these genes in the evolution of squamous carcinoma of the head and neck we evaluated their protein expression by immunohistochemistry in non-dysplastic squamous epithelium, premalignant lesions and oral squamous carcinomas.

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Dermal analogue tumor, an uncommon subtype of basal cell monomorphic adenoma of the parotid gland, has a remarkable clinical and histologic resemblance to dermal cylindroma. Molecular studies of familial and sporadic cylindromas have shown frequent alterations at chromosome 16q12-13 that have recently been found to house the cylindromatosis gene (CYLD). To determine the involvement of the chromosome 16q12-13 region in dermal analogue tumors, we performed loss of heterozygosity analysis using microsatellite markers flanking the cylindromatosis gene locus in 21 sporadic dermal analogue salivary tumors and 12 salivary and dermal lesions from two sisters.

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p73 and p63 are recently cloned genes that share considerable structural and functional homologies with the p53 tumor suppressor gene. These genes, unlike p53, express multiple mRNA isoforms with variable biologic functions, and their suppressor nature has yet to be confirmed. To determine the interrelationship between these genes in the tumorigenesis of head and neck squamous carcinoma (HNSC), we performed immunohistochemical analyses of their protein products and compared the data with clinicopathologic parameters in 38 patients.

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