• Imaging Science in Dentistry
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• 제30권4호
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• pp.275-279
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• 2000

Purpose: Radiation damage is produced and viable cell number is reduced. We need to know the type of cell death by the ionizing radiation and the amount and duration of cell cycle arrest. In this study, we want to identified the main cause of the cellular damage in the oral cancer cells and normal keratinocytes with clinically useful radiation dosage. Materials and Methods: Human gingival tissue specimens obtained from healthy volunteers were used for primary culture of the normal human oral keratinocytes (NHOK). Primary NHOK were prepared from separated epithelial tissue and maintained in keratinocyte growth medium containing 0.15 mM calcium and a supplementary growth factor bullet kit. Fadu and Hep-2 cell lines were obtained from KCLB. Cells were irradiated in a /sup 137/Cs γ-irradiator at the dose of 10 Gy. The dose rate was 5.38 Gy/min. The necrotic cell death was examined with Lactate Dehydrogenase (LDH) activity in the culture medium. Every 4 day after irradiation, LDH activities were read and compared control group. Cell cycle phase distribution and preG1-incidence after radiation were analyzed by flow cytometry using Propidium Iodine staining. Cell cycle analysis were carried out with a FAC Star plus flowcytometry (FACS, Becton Dickinson, USA) and DNA histograms were processed with CELLFIT software (Becton Dickinson, USA). Results: LDH activity increased in all of the experimental cells by the times. This pattern could be seen in the non-irradiated cells, and there was no difference between the non-irradiated cells and irradiated cells. We detected an induction of apoptosis after irradiation with a single dose of 10 Gy. The maximal rate of apoptosis ranged from 4.0% to 8.0% 4 days after irradiation. In all experimental cells, we detected G2/M arrest after irradiation with a single dose of 10 Gy. Yet there were differences in the number of G2/M arrested cells. The maximal rate of the G2/M ranges from 60.0% to 80.0% 24h after irradiation. There is no significant changes on the rate of the G0/G1 phase. Conclusion: Radiation sensitivity was not related with necrosis but cell cycle arrest and apoptosis. These data suggested that more arrested cell is correlated with more apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8553-8557
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• 2016

Background: Accurate dose assessment and correct identification of irradiated from non-irradiated people are goals of biological dosimetry in radiation accidents. Objectives: Changes in the FDXR and the RAD51 gene expression (GE) levels were here analyzed in response to total body exposure (TBE) to a 6 MV x-ray beam in rats. We determined the accuracy for absolute quantification of GE to predict the dose at 24 hours. Materials and Methods: For this in vivo experimental study, using simple randomized sampling, peripheral blood samples were collected from a total of 20 Wistar rats at 24 hours following exposure of total body to 6 MV X-ray beam energy with doses (0.2, 0.5, 2 and 4 Gy) for TBE in Linac Varian 2100C/D (Varian, USA) in Golestan Hospital, in Ahvaz, Iran. Also, 9 rats was irradiated with a 6MV X-ray beam at doses of 1, 2, 3 Gy in 6MV energy as a validation group. A sham group was also included. After RNA extraction and DNA synthesis, GE changes were measured by the QRT-PCR technique and an absolute quantification strategy by taqman methodology in peripheral blood from rats. ROC analysis was used to distinguish irradiated from non-irradiated samples (qualitative dose assessment) at a dose of 2 Gy. Results: The best fits for mean of responses were polynomial equations with a R2 of 0.98 and 0.90 (for FDXR and RAD51 dose response curves, respectively). Dose response of the FDXR gene produced a better mean dose estimation of irradiated "validation" samples compared to the RAD51 gene at doses of 1, 2 and 3 Gy. FDXR gene expression separated the irradiated rats from controls with a sensitivity, specificity and accuracy of 87.5%, 83.5% and 81.3%, respectively, 24 hours after dose of 2 Gy. These values were significantly (p<0.05) higher than the 75%, 75% and 75%, respectively, obtained using gene expression of RAD51 analysis at a dose of 2 Gy. Conclusions: Collectively, these data suggest that absolute quantification by gel purified quantitative RT-PCR can be used to measure the mRNA copies for GE biodosimetry studies at comparable accuracy to similar methods. In the case of TBE with 6MV energy, FDXR gene expression analysis is more precise than that with RAD51 for quantitative and qualitative dose assessment.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.3023-3027
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• 2015

Purpose: To investigate the effects of epidermal growth factor receptor (EGFR), cytokeratin 19 (CK19), cytokeratin 20 (CK20) and survinin gene expression on local control (LC) and overall survival (OS) in patients with locally advanced head and neck cancer (LAHNC) who were administered radiotherapy (RT). Materials and Methods: Twenty-six patients who were admitted to Uludag University Medical Faculty Department of Radiation Oncology with a diagnosis of LAHNC (GIII-GIV) were included in this study. Gene expression was evaluated in tumor tissues and peripheral blood. RNA isolation was performed on paraffinized tumor tissues and peripheral blood samples obtained before RT (BR). The densities of the obtained RNAs were analyzed at 260/280 nm. cDNA samples obtained from total RNA,EGFR, CK19, CK20 and survinin gene expression levels were assessed via the Sybr Green method and data were analyzed with the ${\Delta}{\Delta}Ct$ method. The same process was repeated for peripheral blood samples taken after RT (AR). Results: The female/male ratio was 3:23 and the mean age was 56.5 years (38-75years). After radiotherapy, CK19 and CK20 levels in the peripheral blood were found to be correlated according to Pearson correlation analysis(p=0.049). This result indicates a possibility of remaining positive for CK19 and CK20 in the peripheral blood even after RT in patients with CK19, CK20, and EGFR positive tumors before RT. There was a statistically significant correlation between survinin levels measured BR and AR (p=0.028). Conclusions: In this study, we found that patients with any EGFR, CK19, CK20 or survinin positivity in their peripheral blood obtain less benefit from radiotherapy. A wider patient population and advanced protein analyses are necessary in order to increase the reliability of our findings.

• Asian Pacific Journal of Cancer Prevention
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• 제15권10호
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• pp.4211-4215
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• 2014

Background: Although roles of genetic polymorphisms of leptin receptor (LEPR) gene in several cancers have been documented, the association between polymorphisms of LEPR and clear cell renal cell carcinoma (CC-RCC) remains unknown. The aim of this study was to explore any relation. Materials and Methods: The study population consisted of 77 patients with CC-RCC and 161 healthy control subjects. Polymorphism analyses of Lys109Arg and Gln223Arg were performed by direct DNA sequencing and PCR-restriction fragment length polymorphism approaches respectively. Results: Comparisons of allelic and genotypic frequencies in Lys109Arg and Gln223Arg showed no significant difference between the cases and controls. However, when evaluating the combined genotype of Lys109Arg and Gln223Arg, risk with GG/GG was increased (OR=1.85, 95%CI=1.04-3.30) and with GA/GG or GG/GA was decreased (OR=0.07, 95%CI=0.01-0.54; OR and 95%CI of the latter could not be calculated for a value of zero). Furthermore, the G-G haplotype frequency of Lys109Arg and Gln223Arg in the cases was higher (OR=1.68; 95%CI=1.02-2.76). In contrast, the A-G and G-A haplotype frequencies in the cases were lower than those in the controls (OR=0.06; 95%CI=0.01 to 0.47; OR and 95%CI of the latter could not be calculated for a value of zero). In addition, the Lys109Arg A allele was in LD with the Gln223Arg A allele (d'=0.9399) in the CC-RCC subjects, but not in the controls. Conclusions: Our data suggest that the GG/GG combined genotype and G-G haplotype of Lys109Arg and Gln223Arg can act as evaluating factors for CC-RCC risk.

• 생명과학회지
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• 제19권3호
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• pp.362-365
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• 2009

Hepatocyte nuclear factor-$4{\alpha}$ (HNF-$4{\alpha}$)는 췌장 베타세포의 발생, 분화에 중요한 역할을 하는 전사인자로서, 그 유전자 변이와 MODY와의 연관성이 보고된 바 있다. 특히, 일본인의 경우에는 HNF-$4{\alpha}$ 12352 C>T가 제2형 당뇨병과의 연관성이 있다고 보고되어 있다. 이에 본 연구에서는 HNF-$4{\alpha}$의 유전자 변이와 제2형 당뇨병 사이에 어떠한 연관성이 한국인에서도 있는지 알아보았다. 그 결과, HNF-$4{\alpha}$의 유전자 변이인 12352 C>T와 제2형 당뇨병사이에는 구체적인 연관성이 없는 것으로 확인되었다. 이는 제2형 당뇨병과의 연관성이 있다고 보고된 이전의 일본인이나 유럽인을 대상으로 한 연구결과와 다소 차이가 있는 것이며, 한국인을 위한 고유의 통계적 data로서 의미가 있는 것이라 하겠다. 이러한 차이를 보이는 원인을 유추해본다면, 인종에 따라 서로 다른 유전적 그리고 환경적인 요인의 차이에 의해 다형성이 미치는 영향력에 차이가 있기 때문으로 생각된다. 이는 당뇨병과 같은 질환이 특정한 한 두 개의 유전자 이상에 의해서 발생되기 보다는, 여러 유전자들이 상호 작용함으로써 발생할 뿐만 아니라 환경적인 요인의 영향을 많이 받기 때문에 인종이나 민독과 같은 인구 집단 사이에 유전인자의 차이가 생기는 것으로도 판단된다. 따라서 연구결과의 임상적인 의의를 확실하게 확인하기 위하여서는 향후 대상 환자 수와 대조군을 더욱 늘리고 다양한 HNF-$4{\alpha}$ 유전자 다형성을 후보로 하여 추가적인 연구를 할 필요가 있을 것으로 생각된다.

• Journal of Gastric Cancer
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• 제3권1호
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• pp.50-55
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• 2003

Background: An aberrant function of the mismatch repair system has been reported to underlie carcinogenesis in several tumors, including colorectal and gastric carcinomas, and to induce the typical genotype of microsatellite instability (MSI). Purpose: We aimed to determine the frequency of MSI in early-onset sporadic gastric carcinoma and elucidate the role of promoter methylation in hMLH1 as the mechanism of MSI. Materials and Methods: Thirty-six early-onset sporadic gastric carcinomas were analyzed to determine the status of MSI and the frequency of methylation of the promoter region in hMLH1. MSI was determined using five markers recommended by NCI: MSI-H (high), MSI-L (low), and MSS (Microsatellite stable). Methylation specific PCR (MSP) and direct automated genomic sequencing analysis with DNA modified by sodium bisulfite have been performed to confirm promoter region methylation. All the data were analyzed regarding characteristics of molecular changes, and clinicopathologic variables. Results: The microsatellite status was determined as MSI-H in five cases ($13.8\%$), MSI-L in 13 cases ($36.1\%$), and MSS in 18 cases ($50.0\%$). hMLH1 was methylated in seven cases ($19.4\%$). In all cases of MSI-H, promoter of hMLH1 was methylated, and in two of the 13 cases of MSI-L, hMLH1 promoter methylation was identified. Methylation was not found in any cases of MSS. Promoter methylation in hMLH1 was significantly correlated with MSI status (P<0.001). We could not find any relationship between MSI and clinicopathologic parameters. Conclusion: These results suggest that an abnormal function of the mismatch repair system may be associated with gastric carcinogenesis in more than $10\%$ of early-onset gastric carcinomas and MSI appeared to be closely related to the promoter methylation in hMLH1.

• Journal of Periodontal and Implant Science
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• 제31권1호
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• pp.109-122
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• 2001

Gingival fibroblasts(GF) and periodontal ligament fibroblasts(PDLF) are the major cellular components of periodontal soft connective tissues, but the precise molecular biological differences between these cells are not yet known. In the present study, we investigated the expression of S100A4, S100A2 calcium-binding protein and osteoblast-specific factor 2(OSF-2, Periostin) mRNA in GF and PDLF in vitro through the process of reverse transcription-polymerase chain reaction(RT-PCR) and Northern blot analysis in each. Human GF and PDLF were isolated from the gingival connective tissue and the middle third of freshly extracted healthy third molars. They were cultured in Dulbecco's Modified Eagle Medium(DMEM) containing 10% fetal bovine serum and cells in the third passage were used in the experiments. After extracting total RNA from cultured cells, RT-PCR and Northern analysis were performed using S100A4-, S100A2- and Periostin-specific oligonucleotide primers and subcloned cDNA probes in each. In PT-PCR and Northern analysis, the expression of S100A4 and Periostin mRNA in GF was slightly detectable. Interestingly, the expression of S100A4 and periostin mRNA in PDLF was much higher than that in GF. On the other hand, S100A2 mPNA was highly expressed in both GF and PDLF. Since there was a marked difference of S100A4 and Periostin expression between GF and PDLF in vitro, these data suggest that S100A4 and periostin could be used as a useful marker for distinguishing cultured gingival fibroblasts and periodontal ligament cells.

• Genomics & Informatics
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• 제16권2호
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• pp.22-29
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• 2018

Incorporation of unique barcodes into fission yeast gene deletion collections has enabled the identification of gene functions by growth fitness analysis. For fine tuning, it is important to examine barcode sequences, because mutations arise during strain construction. Out of 8,708 barcodes (4,354 strains) covering 88.5% of all 4,919 open reading frames, 7,734 barcodes (88.8%) were validated as high-fidelity to be inserted at the correct positions by Sanger sequencing. Sequence examination of the 7,734 high-fidelity barcodes revealed that 1,039 barcodes (13.4%) deviated from the original design. In total, 1,284 mutations (mutation rate of 16.6%) exist within the 1,039 mutated barcodes, which is comparable to budding yeast (18%). When the type of mutation was considered, substitutions accounted for 845 mutations (10.9%), deletions accounted for 319 mutations (4.1%), and insertions accounted for 121 mutations (1.6%). Peculiarly, the frequency of substitutions (67.6%) was unexpectedly higher than in budding yeast (~28%) and well above the predicted error of Sanger sequencing (~2%), which might have arisen during the solid-phase oligonucleotide synthesis and PCR amplification of the barcodes during strain construction. When the mutation rate was analyzed by position within 20-mer barcodes using the 1,284 mutations from the 7,734 sequenced barcodes, there was no significant difference between up-tags and down-tags at a given position. The mutation frequency at a given position was similar at most positions, ranging from 0.4% (32/7,734) to 1.1% (82/7,734), except at position 1, which was highest (3.1%), as in budding yeast. Together, well-defined barcode sequences, combined with the next-generation sequencing platform, promise to make the fission yeast gene deletion library a powerful tool for understanding gene function.

• Journal of Periodontal and Implant Science
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• 제33권2호
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• pp.159-166
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• 2003

The purpose of this study was to investigate and compare the frequence of 4 periodontal pathogens in the supra- and subgingival plaque in periodontally healthy subjects. Twenty adult individuals aged 22 to 28 years (mean age 23.65 years) participated in this study. All subjects had no pocket sites more than 3 mm deep, and the sites selected for sampling were all negative for bleeding. After drying and isolation of the sites with cotton rolls, supragingival plaque was sampled using sterile periodontal curette. Each plaque sample was placed in individual tubes containing 500 ml of 1X PBS. After removal of the supragingival sample and any remaining supragingival plaque, subgingival plaque samples were taken from the same sites using sterile curette and placed in similar individual tubes. Identification of 4 putative periodontal pathogens from the samples was performed by polymerase chain reaction based on 16S rDNA. Chi-square test was employed to identify significant explanatory variables for the presence of the 4 periodontal pathogens. The data show that Actinobacillus actinmycetemcomitans, Porphyromonanas gingivalis, Bacteroides forsythus, and Fusobacterium nucleatum occurred in 16.9%, 14.4%, 52.5%, and 80.6%, respectively. No significant differences were noted in the periodontal pathogens between supra- and subgingival plaques according to the kind of teeth. However, the incisors were at higher risk for harboring F. nucleatum (p <0.05). Conclusion: These results reveal that anaerobic periodontal pathogens can be detected in supragingival plaques. Supragingival plaque may function as a reservoir of peri-odotopathogens.

• 대한소아치과학회지
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• 제34권2호
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• pp.247-254
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• 2007

본 연구는 125명의 6-11세 혼합치열기 아동을 대상으로 연령에 따라 초기 혼합치열기 A군(6-8세; 62명)과 후기 혼합치열기 B군(9-11세; 63명)으로 분류하고 유치의 dfs, 영구치의 DFS를 기록한 후 자극성 타액을 채취하여 TYCSB 배지에 배양해서 S. mutans와 S. sobrinus를 구분하였으며 PCR을 시행하여 확인하였다. S. mutans와 S. sobrinus의 분포도와 치아우식증과의 상관관계를 조사하여 다음과 같은 결과를 얻었다. 1. S. mutans와 S. sobrinus의 상관계수는 A군 0.70, B군 0.50로 두 군 모두에서 높은 상관관계를 보였다. 2. S. mutans와 치아우식증과의 관계는 A군(r=0.25)과 B군(r=0.34) 모두에서 약간의 관련성이 나타났다. 3. A군에서 S. sobrinus와 치아우식증간에 상관관계가 없는 것으로 나타났으며, B군(r=0.21)에서는 미약한 상관관계가 성립되었다. 4. S. mutans와 나이의 상관관계는 A군과 B군 모두에서 관련성이 없는 것으로 나타났다. 5. S. sobrinus와 나이의 상관관계는 A군(r=0.32)에서는 약간의 관련성이 나타났고, B군에서는 관련성이 없는 것으로 나타났다.