PURPOSE: The objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti. MATERIALS AND METHODS: Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-microm dimples at 10-microm intervals, and SM30 (n=16) had 5-microm dimples at 25-microm intervals in a 2 x 4 mm2 area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences. RESULTS: The adhesion strength of epithelial cells was higher on Ti surfaces with 5-microm laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins. CONCLUSION: These findings demonstrate that laser dimpling may contribute to improving the periimplant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.
Carcinoma, Squamous Cell ; Cell Proliferation ; Dental Implants ; Epithelial Cells ; Fibroblasts* ; Humans ; Lung ; Titanium*

PURPOSE: The objective of this study was to conduct an in vitro comparative evaluation of polished and laserdimpled titanium (Ti) surfaces to determine whether either surface has an advantage in promoting the attachment of epithelial-like cells and fibroblast to Ti. MATERIALS AND METHODS: Forty-eight coin-shaped samples of commercially pure, grade 4 Ti plates were used in this study. These discs were cleaned to a surface roughness (Ra: roughness centerline average) of 180 nm by polishing and were divided into three groups: SM (n=16) had no dimples and served as the control, SM15 (n=16) had 5-microm dimples at 10-microm intervals, and SM30 (n=16) had 5-microm dimples at 25-microm intervals in a 2 x 4 mm2 area at the center of the disc. Human gingival squamous cell carcinoma cells (YD-38) and human lung fibroblasts (MRC-5) were cultured and used in cell proliferation assays, adhesion assays, immunofluorescent staining of adhesion proteins, and morphological analysis by SEM. The data were analyzed statistically to determine the significance of differences. RESULTS: The adhesion strength of epithelial cells was higher on Ti surfaces with 5-microm laser dimples than on polished Ti surfaces, while the adhesion of fibroblasts was not significantly changed by laser treatment of implant surfaces. However, epithelial cells and fibroblasts around the laser dimples appeared larger and showed increased expression of adhesion proteins. CONCLUSION: These findings demonstrate that laser dimpling may contribute to improving the periimplant soft tissue barrier. This study provided helpful information for developing the transmucosal surface of the abutment.
Carcinoma, Squamous Cell ; Cell Proliferation ; Dental Implants ; Epithelial Cells ; Fibroblasts* ; Humans ; Lung ; Titanium*

PURPOSE: The purpose of this study was to explore the relation of self-efficacy with environmental factors, personality, and academic achievement in medical students. METHODS: Study subjects consisted of 141 first-year medical students at Korea University Medical School during one academic year (2003~2004). All participants completed a 24-item questionnaire on self-efficacy beliefs, a 16-item questionnaire asking demographic and socioeconomic data, and the Temperament and Character Inventory (TCI). Spearman'sorrelation of selfefficacy with other variables was generated. The differences of self-efficacy scores according to the level of satisfaction with school life, total family income per month and the reasons for entering medical college were analyzed by ANOVA. RESULTS: Age and overall satisfaction with school correlated with self-confidence and total family income per month was related to self-regulation. Students who entered medical college due to the socioeconomic stability of medicine showed significantly lower preference for task difficulty than those who had other reasons for entering medical college. The GPAs of premedical studies correlated with self-regulation and the GPAs of Med 1 and the cumulative GPAs of premedical and Med I were related to the preference for task difficulty. CONCLUSION: This result supports that self-efficacy beliefs were related with some environmental factors, personality and academic achievements in medical students.
Humans ; Korea ; Schools, Medical ; Students, Medical* ; Temperament ; Surveys and Questionnaires

PURPOSE: This paper reports on the development a program to foster 'good doctors' who care for their patients with humanism and self-directed learning ability. METHODS: In order to develop the program, Korea University College of Medicine established educational committees. In collaboration, these committees discussed the direction for curriculum reorganization, performed a needs analysis of specified programs, and built realistic strategies for program management. Based upon the needs analyses, through literature review and survey studies, committee discussions and benchmarking of other medical schools, three programs were developed for rearing humanism and self-directed learning ability in medical students were developed: Service learning by experiential learning; Doctoring by small group activities; and Communication skills program by various small group activities. RESULTS: The evaluation by the pre-medical students who participated in the service learning program for one week reveals that through service learning, pre-medical students had an opportunity to obtain the attitudes that encompass the sanctity and dignity of human life and an understanding of cultural, social and religious customs and beliefs that differ from his or her own. In addition, the pre-medical students came to realize that patients' most difficult problems might be caused by non-medical factors as well as medical factors. CONCLUSION: It is needed to grope for the way that leads the active participation of students in the continuous linkage of substantial post-work evaluation and next learning of volunteering in order to make the program of educating the public spirit more than self-learning of experience.
Benchmarking ; Cooperative Behavior ; Curriculum* ; Education, Medical ; Humanism ; Humans ; Korea ; Learning* ; Problem-Based Learning ; Schools, Medical ; Students, Medical

STATEMENT OF PROBLEM: In the process of bone formation, titanium (Ti) surface roughness is an important factor modulating osteoblastic function. PURPOSE: This study was carried out to determine the effect of different Ti surface on biologic responses of a human osteoblast-like cell line (MG63). MATERIALS AND METHODS: MG63 cells were cultured on S (smooth), SLA (sandblasted largegrit and acid etching), HA (hydroxyapatite) Ti. The morphology and attachment of the cells were examined by SEM. The cDNAs prepared from total RNAs of MG63 were hybridized to a human cDNA microarray (1,152 elements). RESULTS: The appearances of the surfaces observed with SEM were different in the three types of dental substrates. The surface of SLA and HA were shown to be rougher than S. MG63 cells cultured on SLA and HA were cell-matrix interaction. In the expression of genes involved in osseointegration, upregulated genes were bone morphogenetic protein, Villin, Integrin, Insulin-like growth factors in different surfaces. Downregulated genes were fibroblast growth factor receptor 4, Bcl 2-related protein, collagen, CD4 in different surfaces. CONCLUSION: The attachment and expression of key osteogenic regulatory genes were enhanced by surface roughness of the dental materials.
Bone Morphogenetic Proteins ; Cell Line ; Collagen ; Dental Materials ; DNA, Complementary ; Genes, Regulator ; Humans ; Oligonucleotide Array Sequence Analysis ; Osseointegration ; Osteoblasts ; Osteogenesis ; Receptor, Fibroblast Growth Factor, Type 4 ; RNA ; Somatomedins ; Titanium

BACKGROUND: Target point mutation of DNA topoisomerase, which is the typical mode of quinolone resistance, cannot explain high level resistance to quinolones. Therefore, many authors looked into over expression of efflux pump as the possibility. After quantificating the arcA mRNA, which controls AcrAB- TolC, the authors tried to find out the difference in the expression of arcA mRNA according to MIC of ciprofloxacin. The authors also tried to determine the usefulness of real time PCR, which is more reproducible and takes less time than preexisting immunoblot assay, through quantification of acrA. MATERIAL AND METHODS: Mutations in topoisomerase (GyrA, ParC) of 20 quinolone resistant E. coli isolates were identified by PCR and direct DNA sequencing. AcrA level was measured by real time PCR. GAPDH of E.coli was used as endogenous control. The expression of acrA was confirmed through northern hybridization method, the results obtained by real time PCR were compared. RESULTS: 1) Topoisomerase mutations were found in all quinolone resistant E. coli strains. 2) AcrA expression in fluoroquinolone-resistant E. coli was quantified by using real time PCR. There was no relationship between the ratio of acrA expression to GAPDH and MIC of ciprofloxacin. 3) With Northern hybridization, we compared the band of acrA to that of GAPDH in compactness and area. No difference in the expression according to MIC could be found. 4) The results of AcrA/GAPDH were significantly correlated between the real-time PCR and northern blot (P<0.05, correlation coefficiency 0.98). CONCLUSION: In this study, no relationship between overexpression of AcrA gene and high level fluoroquinolone resistance. Therefore, we assume that mechanism other than AcrAB efflux pump is involved in and contribute to high-level fluoroquinolone resistance. However, the degree of efflux pump expression could be confirmed with real time PCR using acrA mRNA. Therefore, real time PCR could be used in the molecular biologic study on the mechanism of resistance to antibiotics.
Anti-Bacterial Agents ; Blotting, Northern ; Ciprofloxacin ; DNA Topoisomerases, Type I ; Escherichia* ; Fluoroquinolones* ; Point Mutation ; Polymerase Chain Reaction ; Quinolones ; Real-Time Polymerase Chain Reaction* ; RNA, Messenger ; Sequence Analysis, DNA

BACKGROUND: Target point mutation of DNA topoisomerase, which is the typical mode of quinolone resistance, cannot explain high level resistance to quinolones. Therefore, many authors looked into over expression of efflux pump as the possibility. After quantificating the arcA mRNA, which controls AcrAB- TolC, the authors tried to find out the difference in the expression of arcA mRNA according to MIC of ciprofloxacin. The authors also tried to determine the usefulness of real time PCR, which is more reproducible and takes less time than preexisting immunoblot assay, through quantification of acrA. MATERIAL AND METHODS: Mutations in topoisomerase (GyrA, ParC) of 20 quinolone resistant E. coli isolates were identified by PCR and direct DNA sequencing. AcrA level was measured by real time PCR. GAPDH of E.coli was used as endogenous control. The expression of acrA was confirmed through northern hybridization method, the results obtained by real time PCR were compared. RESULTS: 1) Topoisomerase mutations were found in all quinolone resistant E. coli strains. 2) AcrA expression in fluoroquinolone-resistant E. coli was quantified by using real time PCR. There was no relationship between the ratio of acrA expression to GAPDH and MIC of ciprofloxacin. 3) With Northern hybridization, we compared the band of acrA to that of GAPDH in compactness and area. No difference in the expression according to MIC could be found. 4) The results of AcrA/GAPDH were significantly correlated between the real-time PCR and northern blot (P<0.05, correlation coefficiency 0.98). CONCLUSION: In this study, no relationship between overexpression of AcrA gene and high level fluoroquinolone resistance. Therefore, we assume that mechanism other than AcrAB efflux pump is involved in and contribute to high-level fluoroquinolone resistance. However, the degree of efflux pump expression could be confirmed with real time PCR using acrA mRNA. Therefore, real time PCR could be used in the molecular biologic study on the mechanism of resistance to antibiotics.
Anti-Bacterial Agents ; Blotting, Northern ; Ciprofloxacin ; DNA Topoisomerases, Type I ; Escherichia* ; Fluoroquinolones* ; Point Mutation ; Polymerase Chain Reaction ; Quinolones ; Real-Time Polymerase Chain Reaction* ; RNA, Messenger ; Sequence Analysis, DNA

Methylation events play a critical role in various cellular processes including regulation of gene transcription and proliferation. We observed that methyltransferase activity underwent time-dependent changes in the cytosol of the rat hepatocytes upon partial hepatectomy. However, any change in the methylation of nuclear proteins is not clear during hepatocyte proliferation. The nuclear fraction possesses basal level of methyltransferase to catalyze methylation of several proteins ranging from 7 to 70 kD prior to any hepatecmony. The specific p16 (16 kD) band was transiently and heavily methylated post 1 day hepatectomy, and then became non- detectable, but not in the control liver. Methylation of p16 band was completely inhibited by exogenously added histones, particularly 2AS, 1, 2A and 2B subtypes. The methylated p16 protein remains stable in either acid or alkali- induced demethylation conditions, indicating that methylation is not likely to occur on isoaspartyl or C-terminal cysteinyl residues. Exogenous addition of non-hydrolyzable GTP caused a dose- dependent suppression of a p16 methylation suggesting that G-proteins might play a role as an endogenous methylation inhibitor in vivo. Taken together, we have identified the proliferation event associated-methylation of the nuclear p16 protein in the hepatocytes undergoing liver regeneration.
Alkalies/pharmacology ; Animals ; Cell Proliferation ; Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology ; Hepatectomy ; Hepatocytes/drug effects/*metabolism ; Histones/pharmacology ; Liver Regeneration/drug effects/*physiology ; Methylation/drug effects ; Nuclear Proteins/*metabolism ; Rats ; Research Support, Non-U.S. Gov't ; Sodium Chloride/pharmacology

In this study, we investigated the effects of PAHs and dioxin on mRNA and plasma protein expression using genomic and proteomic analysis for automobile emission inspectors and waste incineration workers. About 54 workers from automobile emission inspection offices, 31 workers from waste incinerating company and 84 unexposed healthy subjects were enrolled in this study. Urine and air samples were collected and analyzed by HPLC and GC/MS. Comet assays were carried out to evaluate any DNA damage in mononuclear and polynuclear cells. A significant difference in Olive tail moments in mononuclear cells was observed between exposed and control subjects (P <0.0001). To examine the differences of the gene expression profile in automobile emission inspectors and waste incineration workers, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 total genes. The gene expression profiles showed that 11 genes were up-regulated and 4 genes were down-regulated in waste incinerating workers as compared with controls. Plasma proteins were analyzed by 2-dimentional electrophoresis with pH 3-10 NL IPG Dry strip. The protein expression profiles showed that 8 proteins were up- regulated and 1 protein, haptoglobin, was down- regulated in automobile emission inspectors and waste incineration workers. Serum paraoxonase/ arylesterase was found only in the plasma of waste incineration workers. The expression of genes and proteins involved in oxidative stress were up-regulated in both automobile emission inspectors and waste incineration workers. Several proteins, such as transthyrethin, sarcolectin and haptoglobin, that were highly up- or down-regulated, could serve as biological monitoring markers for future study.
Adult ; Aged ; Biological Markers/analysis ; DNA Fragmentation ; Environmental Monitoring/*methods ; Gene Expression Profiling ; Genetic Markers ; Genomics ; Humans ; *Incineration ; Middle Aged ; Naphthols/urine ; Occupational Exposure/analysis ; Oligonucleotide Array Sequence Analysis ; Polycyclic Hydrocarbons, Aromatic/analysis/*toxicity ; Proteomics ; Pyrenes/analysis ; Research Support, Non-U.S. Gov't ; Tetrachlorodibenzodioxin/analysis/*toxicity ; *Vehicle Emissions

Microarray technology allows the simultaneous analysis of gene expression patterns of thousands of genes, in a systematic fashion, under a similar set of experimental conditions, thus making the data highly comparable. In some cases arrays are used simply as a primary screen leading to downstream molecular characterization of individual gene candidates. In other cases, the goal of expression profiling is to begin to identify complex regulatory networks underlying developmental processes and disease states. Microarrays were originally used with cell lines or other simple model systems. More recently, microarrays have been used in the analysis of more complex biological tissues including neural systems and the brain. The application of cDNA arrays in neuropsychiatry has lagged behind other fields for a number of reasons. These include a requirement for a large amount of input probe RNA in fluorescent-glass based array systems and the cellular complexity introduced by multicellular brain and neural tissues. An additional factor that impacts the general use of microarrays in neuropsychiatry is the lack of availability of sequenced clone sets from model systems. While human cDNA clones have been widely available, high quality rat, mouse, and drosophilae, among others are just becoming widely available. A final factor in the application of cDNA microarrays in neuropsychiatry is cost of commercial arrays. As academic microarray facilitates become more commonplace custom made arrays will become more widely available at a lower cost allowing more widespread applications. In summary, microarray technology is rapidly having an impact on many areas of biomedical research. Radioisotope-nylon based microarrays offer alternatives that may in some cases be more sensitive, flexible, inexpensive, and universal as compared to other array formats, such as fluorescent-glass arrays. In some situations of limited RNA or exotic species, radioactive membrane microarrays may be the most practical experimental approach in studying psychiatric and neurodegenerative disorders, and other complex questions in the brain.
Animals ; Brain ; Cell Line ; Clone Cells ; DNA, Complementary* ; Drosophila ; Gene Expression ; Humans ; Membranes ; Mice ; Neurodegenerative Diseases ; Neuropsychiatry ; Oligonucleotide Array Sequence Analysis* ; Rats ; RNA