Jae Choi - Academia.edu (original) (raw)

Papers by Jae Choi

Genomics & Informatics, 2013

Genomic instability, which occurs through both genetic mechanisms (underlying inheritable phenoty... more Genomic instability, which occurs through both genetic mechanisms (underlying inheritable phenotypic variations caused by DNA sequence-dependent alterations, such as mutation, deletion, insertion, inversion, translocation, and chromosomal aneuploidy) and epigenomic aberrations (underlying inheritable phenotypic variations caused by DNA sequence-independent alterations caused by a change of chromatin structure, such as DNA methylation and histone modifications), is known to promote tumorigenesis and tumor progression. Mechanisms involve both genomic instability and epigenomic aberrations that lose or gain the function of genes that impinge on tumor suppression/prevention or oncogenesis. Growing evidence points to an epigenome-wide disruption that involves large-scale DNA hypomethylation but specific hypermethylation of tumor suppressor genes, large blocks of aberrant histone modifications, and abnormal miRNA expression profile. Emerging molecular details regarding the modulation of these epigenetic events in cancer are used to illustrate the alterations of epigenetic molecules, and their consequent malfunctions could contribute to cancer biology. More recently, intriguing evidence supporting that genetic and epigenetic mechanisms are not separate events in cancer has been emerging; they intertwine and take advantage of each other during tumorigenesis. In addition, we discuss the collusion between epigenetics and genetics mediated by heterochromatin protein 1, a major component of heterochromatin, in order to maintain genome integrity.

Cancer research and treatment : official journal of Korean Cancer Association, Jan 6, 2015

Heterochromatin protein 1γ (HP1γ) interacts with chromosomes by binding to lysine 9-methylated hi... more Heterochromatin protein 1γ (HP1γ) interacts with chromosomes by binding to lysine 9-methylated histone H3 or DNA/RNA. HP1γ is involved in various biological processes. The purpose of this study is to gain an understanding of how HP1γ functions in these processes by identifying HP1γ-binding proteins using mass spectrometry. We performed affinity purification of HP1γ-binding proteins using G1/S phase or prometaphase HEK293T cell lysates that transiently express mock or FLAG-HP1γ. Coomassie staining was performed for HP1γ-binding complexes, using cell lysates prepared by affinity chromatography FLAG-agarose beads, and the bands were digested and then analyzed using a mass spectrometry. We identified 99 HP1γ-binding proteins with diverse cellular functions, including spliceosome, regulation of the actin cytoskeleton, tight junction, pathogenic Escherichia coli infection, mTOR signaling pathway, nucleotide excision repair, DNA replication, homologous recombination, and mismatch repair. O...

Nucleic Acids Research, 2012

Heterochromatin protein 1γ (HP1γ) is a chromatin protein involved in gene silencing. Herein, we s... more Heterochromatin protein 1γ (HP1γ) is a chromatin protein involved in gene silencing. Herein, we show that HP1γ interacts with breast cancer type 1 susceptibility protein (BRCA1) and regulates BRCA1-mediated transcription via modulation of promoter occupancy and histone modification. We used several HP1γ mutants and small interfering RNAs for histone methyltransferases to show that BRCA1-HP1γ interaction, but not methylated histone binding, is important in HP1γ repression of BRCA1-mediated transcription. Time-lapse studies on promoter association and histone methylation after DNA damage revealed that HP1γ accumulates at the promoter before DNA damage, but BRCA1 is recruited at the promoter after the damage while promoter-resident HP1γ is disassembled. Importantly, HP1γ assembly recovers after release from the damage in a BRCA1-HP1γ interaction-dependent manner and targets SUV39H1. HP1γ/SUV39H1 restoration at the promoter results in BRCA1 disassembly and histone methylation, after which transcription repression resumes. We propose that through interaction with BRCA1, HP1γ is guided to the BRCA1 target promoter during recovery and functions in the activation-repression switch and recovery from BRCA1-mediated transcription in response to DNA damage.

Experimental and Molecular Medicine, 2010

Chromatin structure has a crucial role in a diversity of physiological processes, including devel... more Chromatin structure has a crucial role in a diversity of physiological processes, including development, differentiation and stress responses, via regulation of transcription, DNA replication and DNA damage repair. Histone deacetylase (HDAC) inhibitors regulate chromatin structure and activate the DNA damage checkpoint pathway involving Ataxia-telangiectasia mutated (ATM). Herein, we investigated the impact of histone acetylation/deacetylation modification on the ATM-mediated transcriptional modulation to provide a better understanding of the transcriptional function of ATM. The prototype HDAC inhibitor trichostain A (TSA) reprograms expression of the myeloid cell leukemia-1 (MCL1) and Gadd45 genes via the ATM-mediated signal pathway. Transcription of MCL1 and Gadd45alpha is enhanced following TSA treatment in ATM(+) cells, but not in isogenic ATM(-) or kinase-dead ATM expressing cells, in the ATM-activated E2F1 or BRCA1- dependent manner, respectively. These findings suggest that ATM and its kinase activity are essential for the TSA-induced regulation of gene expression. In summary, ATM controls the transcriptional upregulation of MCL1 and Gadd45 through the activation of the ATM-mediated signal pathway in response to HDAC inhibition. These findings are important in helping to design combinatory treatment schedules for anticancer radio- or chemo-therapy with HDAC inhibitors.

Biochemical and Biophysical Research Communications, 2010

Acetyltransferase, p300 is a transcriptional cofactor of signal-responsive transcriptional regula... more Acetyltransferase, p300 is a transcriptional cofactor of signal-responsive transcriptional regulation. The surveillance kinase ataxia-telangiectasia mutated (ATM) plays a central role in regulation of a wide range of cellular DNA damage responses. Here, we investigated whether and how ATM mediates phosphorylation of p300 in response to DNA damage and how p300 phosphorylation is functionally linked to DNA damage. ATM-phosphorylated p300 in vitro and in vivo, in response to DNA damage. Phosphorylation of p300 proteins was observed upon c-irradiation in ATM + cells but not ATM À cells. Importantly, expression of nonphosphorylatable serine to alanine form of p300 (S106A) destabilized both p300 and NBS1 proteins, after DNA damage. These data demonstrate that ATM transduces a DNA damage signal to p300, and that ATM-dependent phosphorylation of p300 is required for stabilization of NBS1 proteins in response to DNA damage.

Annals of dermatology, 2015

Pigmented purpuric dermatoses (PPD) are a spectrum of disorders characterized by a distinct purpu... more Pigmented purpuric dermatoses (PPD) are a spectrum of disorders characterized by a distinct purpuric rash. Although PPD can be easily diagnosed, the disease entity remains an enigma and a therapeutic challenge. The purpose of this study was to investigate the characteristics and clinical manifestations of PPD and to elucidate the relationship between assumed etiologic factors and the clinical manifestations of PPD and treatment responses. Retrograde analyses were performed to identify appropriate PPD patients who visited Korea University Medical Center Anam Hospital from 2002 to 2012. Information on 113 patients with PPD was analyzed, and 38 subjects with skin biopsy were included for this study. Schamberg's disease was the most frequent clinical type (60.5%). Concomitant diseases included hypertension (15.8%), diabetes (10.5%), and others. Associated medication histories included statins (13.2%), beta blockers (10.5%), and others. Possibly associated etiologic factors were rece...

Annals of dermatology, 2015

Annals of dermatology, 2015

Tinea incognito is a dermatophytic infection induced by immunosuppressive agents that lacks the c... more Tinea incognito is a dermatophytic infection induced by immunosuppressive agents that lacks the classic features of a typical fungal infection. Although the treatment of tinea incognito is simple and relatively easy, its clinical manifestation varies and can masquerade as various skin disorders, causing misdiagnosis and thus preventing prompt and appropriate treatment. Here, we report an interesting case of tinea incognito occurring after topical steroid administration in an immunosuppressed patient with dermatitis artefacta. A 40-year-old female patient who had been taking systemic glucocorticoid for 4 years for chronic inflammatory demyelinating polyneuropathy presented with itching multiple erythematous erosive lesions on the face and upper chest for 2 months. Initial biopsy produced nonspecific findings. The skin lesion was aggravated and became polycyclic and erythematous; after azathioprine was added, her chronic inflammatory demyelinating polyneuropathy became aggravated. A s...

Lecture Notes in Computer Science, 1999

This paper proposes a concept-based and an inexact image match retrieval technique based on fuzzy... more This paper proposes a concept-based and an inexact image match retrieval technique based on fuzzy triples. The most general method adopted to index and retrieve images based on this spatial structure may be the triple framework. However, this framework has two significant drawbacks; one is that it can not support concept-based image retrieval and the other is that it fails

International journal of dermatology, 2007

Managing metadata of documents is a difficult and slippery for desktop users. A wide variety of t... more Managing metadata of documents is a difficult and slippery for desktop users. A wide variety of technologies have been applied for supporting requirements of metadata management, ranging from the acquisition, creation, maintenance, retrieval, reuse, and publishing of metadata. We introduce essential concepts of a semantic document and implement the necessary functionality of metadata managing process. We also propose that three tasks are required to facilitate unambiguous representation of metadata in documents: using XMP to store metadata with the file itself, using ontologies to represent semantic concepts and using Social Web services to interact with web based resources. So our approach allows a user to interact and share the resources among a Desktop and Web more easily.

The Journal of dermatological treatment, Jan 9, 2014

Background: While the Q-switched Alexandrite laser (QSAL) and the Q-switched neodymium: yttrium-a... more Background: While the Q-switched Alexandrite laser (QSAL) and the Q-switched neodymium: yttrium-aluminum-garnet (QSNY) laser have been widely used in treating nevus of Ota, few studies compared them. Objective: To compare the efficacies of the QSAL and the QSNY laser in the treatment of nevus of Ota in Korean patients. Methods and materials: A retrospective multicenter study was conducted in 76 patients with nevus of Ota. Thirty-one patients were treated with a QSAL (5.5-8.0 J/cm(2), 4-mm spot size) and 45 patients were treated with QSNY laser (6.0-12.0 J/cm(2), 2-mm spot size). Treatment outcomes were categorized into five grades and the results were compared with the relevant variables taken into account using multivariate logistic regression analysis. Results: QSAL treatment was more likely to achieve a better response compared with that with QSNY laser treatment. The odds ratio of achieving an excellent response, compared with the odds ratio of having a poor response, was 12.213...

Online Information Review, 2010

Purpose – The purpose of this research is to investigate some general features of folksonomies an... more Purpose – The purpose of this research is to investigate some general features of folksonomies and user-generated content with copyright issues, and to present semantic representation for folksonomies using a tag ontology that can be used to represent tagging data at a semantic level using Semantic Web technologies. Design/methodology/approach – An exploratory study is described that features current social tagging

Molecular & Cellular Toxicology, 2011

Despite widespread use of silicon dioxide (SiO 2 ) NPs in industry and in our daily lives, no stu... more Despite widespread use of silicon dioxide (SiO 2 ) NPs in industry and in our daily lives, no studies so far have evaluated the potential of their skin phototoxicity and sensitization. This study was designed to investigate the potential of phototoxicity and sensitization of SiO 2 NPs. Assessment of the potential of skin phototoxicity was carried out using the 3T3 neutral red uptake test, an HSEM, and an animal model. The potential of skin sensitization was evaluated by a non-radioisotope local lymph node assay (non-RI LLNA). Findings from the present study suggest that the HSEM may be a reasonable model system for evaluation of skin phototoxicity of NPs. In addition, our data demonstrate that non-RI LLNA may be a useful method for identification of skin sensitization of NPs. In this study, we showed that SiO 2 NPs do not induce phototoxicity or skin sensitization.

International Journal of Dermatology, 2010

Background Egr-1 is known to play an important role in cell growth, differentiation, and cell sur... more Background Egr-1 is known to play an important role in cell growth, differentiation, and cell survival. Human skin dermal fibroblasts (HSDF) may be an important target for adverse effects of tobacco components. However, nicotinic effect for early growth response-1 (Egr-1) expression is unknown in HSDF.

Annals of Dermatology, 2014

The rapid development of information and communication technology has replaced traditional books ... more The rapid development of information and communication technology has replaced traditional books by electronic versions. Most print dermatology journals have been replaced with electronic journals (e-journals), which are readily used by clinicians and medical students. Objective: The objectives of this study were to determine whether e-readers are appropriate for reading dermatology journals, to conduct an attitude study of both medical personnel and students, and to find a way of improving e-book use in the field of dermatology. Methods: All articles in the Korean Journal of Dermatology published from January 2010 to December 2010 were utilized in this study. Dermatology house officers, student trainees in their fourth year of medical school, and interns at Korea University Medical Center participated in the study. After reading the articles with Kindle 2, their impressions and evaluations were recorded using a questionnaire with a 5-point Likert scale. Results: The results demonstrated that gray-scale e-readers might not be suitable for reading dermatology journals, especially for case reports compared to the original articles. Only three of the thirty-one respondents preferred e-readers to printed papers. The most common suggestions from respondents to encourage usage of e-books in the field of dermatology were the introduction of a color display, followed by the use of a touch screen system, a cheaper price, and ready-to-print capabilities. Conclusion: In con-clusion, our study demonstrated that current e-readers might not be suitable for reading dermatology journals. However, they may be utilized in selected situations according to the type and topic of the papers. (Ann Dermatol 26(6) 700∼705,

Toxicology, 2010

Assessments of skin irritation potentials are important aspects of the development of nanotechnol... more Assessments of skin irritation potentials are important aspects of the development of nanotechnology. Nanosilica is currently being widely used for commercial purposes, but little literature is available on its skin toxicity and irritation potential. This study was designed to determine whether nanosilica has the potential to cause acute cutaneous toxicity, using cultured HaCaT keratinocytes (CHK), a human skin equivalent model (HSEM), and invivo model. Nanosilica was characterized by scanning electron microscopy. We evaluated the cytotoxic effects of nanosilica on CHKs and the HSEM. In addition, we also investigated whether two commercially available nanosilicas with different sizes (7 and 10-20 nm) have different effects. To confirm invitro results, we evaluated the irritation potentials of nanosilicas on rabbit skin. Nanosilicas reduced the cell viabilities of CHKs in a dose-dependent manner. However, the HSEM revealed no irritation at 500 microg/ml of nanosilica. Furthermore, this result concurred with Draize skin irritation test findings. The present study data indicate that nanosilica does not cause acute cutaneous irritation. Furthermore, this study shows that the HSEM used provides more useful screening data than the conventional cell culture model on the relative toxicities of NPs.

Indian Journal of Dermatology, Venereology, and Leprology, 2014

Dermatologic Surgery, 2009

BACKGROUND Becker's nevus (BN) can be a distressing cosmetic handicap for patients and a treatmen... more BACKGROUND Becker's nevus (BN) can be a distressing cosmetic handicap for patients and a treatment challenge for physicians. Various treatment modalities have been used, but repigmentation commonly occurs after treatment.

Dermatologic Surgery, 2007

ABSTRACT

Genomics & Informatics, 2013

Genomic instability, which occurs through both genetic mechanisms (underlying inheritable phenoty... more Genomic instability, which occurs through both genetic mechanisms (underlying inheritable phenotypic variations caused by DNA sequence-dependent alterations, such as mutation, deletion, insertion, inversion, translocation, and chromosomal aneuploidy) and epigenomic aberrations (underlying inheritable phenotypic variations caused by DNA sequence-independent alterations caused by a change of chromatin structure, such as DNA methylation and histone modifications), is known to promote tumorigenesis and tumor progression. Mechanisms involve both genomic instability and epigenomic aberrations that lose or gain the function of genes that impinge on tumor suppression/prevention or oncogenesis. Growing evidence points to an epigenome-wide disruption that involves large-scale DNA hypomethylation but specific hypermethylation of tumor suppressor genes, large blocks of aberrant histone modifications, and abnormal miRNA expression profile. Emerging molecular details regarding the modulation of these epigenetic events in cancer are used to illustrate the alterations of epigenetic molecules, and their consequent malfunctions could contribute to cancer biology. More recently, intriguing evidence supporting that genetic and epigenetic mechanisms are not separate events in cancer has been emerging; they intertwine and take advantage of each other during tumorigenesis. In addition, we discuss the collusion between epigenetics and genetics mediated by heterochromatin protein 1, a major component of heterochromatin, in order to maintain genome integrity.

Cancer research and treatment : official journal of Korean Cancer Association, Jan 6, 2015

Heterochromatin protein 1γ (HP1γ) interacts with chromosomes by binding to lysine 9-methylated hi... more Heterochromatin protein 1γ (HP1γ) interacts with chromosomes by binding to lysine 9-methylated histone H3 or DNA/RNA. HP1γ is involved in various biological processes. The purpose of this study is to gain an understanding of how HP1γ functions in these processes by identifying HP1γ-binding proteins using mass spectrometry. We performed affinity purification of HP1γ-binding proteins using G1/S phase or prometaphase HEK293T cell lysates that transiently express mock or FLAG-HP1γ. Coomassie staining was performed for HP1γ-binding complexes, using cell lysates prepared by affinity chromatography FLAG-agarose beads, and the bands were digested and then analyzed using a mass spectrometry. We identified 99 HP1γ-binding proteins with diverse cellular functions, including spliceosome, regulation of the actin cytoskeleton, tight junction, pathogenic Escherichia coli infection, mTOR signaling pathway, nucleotide excision repair, DNA replication, homologous recombination, and mismatch repair. O...

Nucleic Acids Research, 2012

Heterochromatin protein 1γ (HP1γ) is a chromatin protein involved in gene silencing. Herein, we s... more Heterochromatin protein 1γ (HP1γ) is a chromatin protein involved in gene silencing. Herein, we show that HP1γ interacts with breast cancer type 1 susceptibility protein (BRCA1) and regulates BRCA1-mediated transcription via modulation of promoter occupancy and histone modification. We used several HP1γ mutants and small interfering RNAs for histone methyltransferases to show that BRCA1-HP1γ interaction, but not methylated histone binding, is important in HP1γ repression of BRCA1-mediated transcription. Time-lapse studies on promoter association and histone methylation after DNA damage revealed that HP1γ accumulates at the promoter before DNA damage, but BRCA1 is recruited at the promoter after the damage while promoter-resident HP1γ is disassembled. Importantly, HP1γ assembly recovers after release from the damage in a BRCA1-HP1γ interaction-dependent manner and targets SUV39H1. HP1γ/SUV39H1 restoration at the promoter results in BRCA1 disassembly and histone methylation, after which transcription repression resumes. We propose that through interaction with BRCA1, HP1γ is guided to the BRCA1 target promoter during recovery and functions in the activation-repression switch and recovery from BRCA1-mediated transcription in response to DNA damage.

Experimental and Molecular Medicine, 2010

Chromatin structure has a crucial role in a diversity of physiological processes, including devel... more Chromatin structure has a crucial role in a diversity of physiological processes, including development, differentiation and stress responses, via regulation of transcription, DNA replication and DNA damage repair. Histone deacetylase (HDAC) inhibitors regulate chromatin structure and activate the DNA damage checkpoint pathway involving Ataxia-telangiectasia mutated (ATM). Herein, we investigated the impact of histone acetylation/deacetylation modification on the ATM-mediated transcriptional modulation to provide a better understanding of the transcriptional function of ATM. The prototype HDAC inhibitor trichostain A (TSA) reprograms expression of the myeloid cell leukemia-1 (MCL1) and Gadd45 genes via the ATM-mediated signal pathway. Transcription of MCL1 and Gadd45alpha is enhanced following TSA treatment in ATM(+) cells, but not in isogenic ATM(-) or kinase-dead ATM expressing cells, in the ATM-activated E2F1 or BRCA1- dependent manner, respectively. These findings suggest that ATM and its kinase activity are essential for the TSA-induced regulation of gene expression. In summary, ATM controls the transcriptional upregulation of MCL1 and Gadd45 through the activation of the ATM-mediated signal pathway in response to HDAC inhibition. These findings are important in helping to design combinatory treatment schedules for anticancer radio- or chemo-therapy with HDAC inhibitors.

Biochemical and Biophysical Research Communications, 2010

Acetyltransferase, p300 is a transcriptional cofactor of signal-responsive transcriptional regula... more Acetyltransferase, p300 is a transcriptional cofactor of signal-responsive transcriptional regulation. The surveillance kinase ataxia-telangiectasia mutated (ATM) plays a central role in regulation of a wide range of cellular DNA damage responses. Here, we investigated whether and how ATM mediates phosphorylation of p300 in response to DNA damage and how p300 phosphorylation is functionally linked to DNA damage. ATM-phosphorylated p300 in vitro and in vivo, in response to DNA damage. Phosphorylation of p300 proteins was observed upon c-irradiation in ATM + cells but not ATM À cells. Importantly, expression of nonphosphorylatable serine to alanine form of p300 (S106A) destabilized both p300 and NBS1 proteins, after DNA damage. These data demonstrate that ATM transduces a DNA damage signal to p300, and that ATM-dependent phosphorylation of p300 is required for stabilization of NBS1 proteins in response to DNA damage.

Annals of dermatology, 2015

Pigmented purpuric dermatoses (PPD) are a spectrum of disorders characterized by a distinct purpu... more Pigmented purpuric dermatoses (PPD) are a spectrum of disorders characterized by a distinct purpuric rash. Although PPD can be easily diagnosed, the disease entity remains an enigma and a therapeutic challenge. The purpose of this study was to investigate the characteristics and clinical manifestations of PPD and to elucidate the relationship between assumed etiologic factors and the clinical manifestations of PPD and treatment responses. Retrograde analyses were performed to identify appropriate PPD patients who visited Korea University Medical Center Anam Hospital from 2002 to 2012. Information on 113 patients with PPD was analyzed, and 38 subjects with skin biopsy were included for this study. Schamberg's disease was the most frequent clinical type (60.5%). Concomitant diseases included hypertension (15.8%), diabetes (10.5%), and others. Associated medication histories included statins (13.2%), beta blockers (10.5%), and others. Possibly associated etiologic factors were rece...

Annals of dermatology, 2015

Annals of dermatology, 2015

Tinea incognito is a dermatophytic infection induced by immunosuppressive agents that lacks the c... more Tinea incognito is a dermatophytic infection induced by immunosuppressive agents that lacks the classic features of a typical fungal infection. Although the treatment of tinea incognito is simple and relatively easy, its clinical manifestation varies and can masquerade as various skin disorders, causing misdiagnosis and thus preventing prompt and appropriate treatment. Here, we report an interesting case of tinea incognito occurring after topical steroid administration in an immunosuppressed patient with dermatitis artefacta. A 40-year-old female patient who had been taking systemic glucocorticoid for 4 years for chronic inflammatory demyelinating polyneuropathy presented with itching multiple erythematous erosive lesions on the face and upper chest for 2 months. Initial biopsy produced nonspecific findings. The skin lesion was aggravated and became polycyclic and erythematous; after azathioprine was added, her chronic inflammatory demyelinating polyneuropathy became aggravated. A s...

Lecture Notes in Computer Science, 1999

This paper proposes a concept-based and an inexact image match retrieval technique based on fuzzy... more This paper proposes a concept-based and an inexact image match retrieval technique based on fuzzy triples. The most general method adopted to index and retrieve images based on this spatial structure may be the triple framework. However, this framework has two significant drawbacks; one is that it can not support concept-based image retrieval and the other is that it fails

International journal of dermatology, 2007

Managing metadata of documents is a difficult and slippery for desktop users. A wide variety of t... more Managing metadata of documents is a difficult and slippery for desktop users. A wide variety of technologies have been applied for supporting requirements of metadata management, ranging from the acquisition, creation, maintenance, retrieval, reuse, and publishing of metadata. We introduce essential concepts of a semantic document and implement the necessary functionality of metadata managing process. We also propose that three tasks are required to facilitate unambiguous representation of metadata in documents: using XMP to store metadata with the file itself, using ontologies to represent semantic concepts and using Social Web services to interact with web based resources. So our approach allows a user to interact and share the resources among a Desktop and Web more easily.

The Journal of dermatological treatment, Jan 9, 2014

Background: While the Q-switched Alexandrite laser (QSAL) and the Q-switched neodymium: yttrium-a... more Background: While the Q-switched Alexandrite laser (QSAL) and the Q-switched neodymium: yttrium-aluminum-garnet (QSNY) laser have been widely used in treating nevus of Ota, few studies compared them. Objective: To compare the efficacies of the QSAL and the QSNY laser in the treatment of nevus of Ota in Korean patients. Methods and materials: A retrospective multicenter study was conducted in 76 patients with nevus of Ota. Thirty-one patients were treated with a QSAL (5.5-8.0 J/cm(2), 4-mm spot size) and 45 patients were treated with QSNY laser (6.0-12.0 J/cm(2), 2-mm spot size). Treatment outcomes were categorized into five grades and the results were compared with the relevant variables taken into account using multivariate logistic regression analysis. Results: QSAL treatment was more likely to achieve a better response compared with that with QSNY laser treatment. The odds ratio of achieving an excellent response, compared with the odds ratio of having a poor response, was 12.213...

Online Information Review, 2010

Purpose – The purpose of this research is to investigate some general features of folksonomies an... more Purpose – The purpose of this research is to investigate some general features of folksonomies and user-generated content with copyright issues, and to present semantic representation for folksonomies using a tag ontology that can be used to represent tagging data at a semantic level using Semantic Web technologies. Design/methodology/approach – An exploratory study is described that features current social tagging

Molecular & Cellular Toxicology, 2011

Despite widespread use of silicon dioxide (SiO 2 ) NPs in industry and in our daily lives, no stu... more Despite widespread use of silicon dioxide (SiO 2 ) NPs in industry and in our daily lives, no studies so far have evaluated the potential of their skin phototoxicity and sensitization. This study was designed to investigate the potential of phototoxicity and sensitization of SiO 2 NPs. Assessment of the potential of skin phototoxicity was carried out using the 3T3 neutral red uptake test, an HSEM, and an animal model. The potential of skin sensitization was evaluated by a non-radioisotope local lymph node assay (non-RI LLNA). Findings from the present study suggest that the HSEM may be a reasonable model system for evaluation of skin phototoxicity of NPs. In addition, our data demonstrate that non-RI LLNA may be a useful method for identification of skin sensitization of NPs. In this study, we showed that SiO 2 NPs do not induce phototoxicity or skin sensitization.

International Journal of Dermatology, 2010

Background Egr-1 is known to play an important role in cell growth, differentiation, and cell sur... more Background Egr-1 is known to play an important role in cell growth, differentiation, and cell survival. Human skin dermal fibroblasts (HSDF) may be an important target for adverse effects of tobacco components. However, nicotinic effect for early growth response-1 (Egr-1) expression is unknown in HSDF.

Annals of Dermatology, 2014

The rapid development of information and communication technology has replaced traditional books ... more The rapid development of information and communication technology has replaced traditional books by electronic versions. Most print dermatology journals have been replaced with electronic journals (e-journals), which are readily used by clinicians and medical students. Objective: The objectives of this study were to determine whether e-readers are appropriate for reading dermatology journals, to conduct an attitude study of both medical personnel and students, and to find a way of improving e-book use in the field of dermatology. Methods: All articles in the Korean Journal of Dermatology published from January 2010 to December 2010 were utilized in this study. Dermatology house officers, student trainees in their fourth year of medical school, and interns at Korea University Medical Center participated in the study. After reading the articles with Kindle 2, their impressions and evaluations were recorded using a questionnaire with a 5-point Likert scale. Results: The results demonstrated that gray-scale e-readers might not be suitable for reading dermatology journals, especially for case reports compared to the original articles. Only three of the thirty-one respondents preferred e-readers to printed papers. The most common suggestions from respondents to encourage usage of e-books in the field of dermatology were the introduction of a color display, followed by the use of a touch screen system, a cheaper price, and ready-to-print capabilities. Conclusion: In con-clusion, our study demonstrated that current e-readers might not be suitable for reading dermatology journals. However, they may be utilized in selected situations according to the type and topic of the papers. (Ann Dermatol 26(6) 700∼705,

Toxicology, 2010

Assessments of skin irritation potentials are important aspects of the development of nanotechnol... more Assessments of skin irritation potentials are important aspects of the development of nanotechnology. Nanosilica is currently being widely used for commercial purposes, but little literature is available on its skin toxicity and irritation potential. This study was designed to determine whether nanosilica has the potential to cause acute cutaneous toxicity, using cultured HaCaT keratinocytes (CHK), a human skin equivalent model (HSEM), and invivo model. Nanosilica was characterized by scanning electron microscopy. We evaluated the cytotoxic effects of nanosilica on CHKs and the HSEM. In addition, we also investigated whether two commercially available nanosilicas with different sizes (7 and 10-20 nm) have different effects. To confirm invitro results, we evaluated the irritation potentials of nanosilicas on rabbit skin. Nanosilicas reduced the cell viabilities of CHKs in a dose-dependent manner. However, the HSEM revealed no irritation at 500 microg/ml of nanosilica. Furthermore, this result concurred with Draize skin irritation test findings. The present study data indicate that nanosilica does not cause acute cutaneous irritation. Furthermore, this study shows that the HSEM used provides more useful screening data than the conventional cell culture model on the relative toxicities of NPs.

Indian Journal of Dermatology, Venereology, and Leprology, 2014

Dermatologic Surgery, 2009

BACKGROUND Becker's nevus (BN) can be a distressing cosmetic handicap for patients and a treatmen... more BACKGROUND Becker's nevus (BN) can be a distressing cosmetic handicap for patients and a treatment challenge for physicians. Various treatment modalities have been used, but repigmentation commonly occurs after treatment.

Dermatologic Surgery, 2007

ABSTRACT