Effect of pH variation on flexural and compressive properties of composite resins / 대한치과재료학회지

The pH of the oral cavity can dynamically change due to diverse foods and beverages served. The purpose of the present study was to evaluate flexural and compressive properties of composite resins after immersion in solutions of different pHs. Four composite resins were cured and immersed in test solutions of different pHs (3, 7.1, and 9) for 2 weeks. Flexural and compressive properties (strength and modulus) were evaluated using universal test machine. After immersion, initial flexural and compressive strength significantly changed to 1.5–30.0% and 0.3–19.6%, respectively; flexural and compressive modulus significantly changed to 4.4–29.0% and 3.5–21.5%, respectively. However, the values obtained from solutions of different pHs were not significantly and consistently different to each other.

Bleaching of stained resin using nitrogen doped-TiO₂ nanoparticles / 대한치과재료학회지

There has been increasing use of the H₂O₂-based teeth bleaching agents. The purpose of this study was to evaluate the bleaching effectiveness of the laser irradiation combined with nitrogen doped-TiO₂ nanoparticles (NPs) on the stained resin. Nitrogen (N) doped-TiO₂ NPs were prepared under sol-gel method. Light absorbance, X-ray diffraction patterns of NPs, and bleaching of methylene blue and stained resins were evaluated. For bleaching of stained resin, NPs-containing gel was used. For irradiation, light of two different wavelengths was used. Unlike TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂, which have used TiN as a precursor, showed a new rutile phase at the TiN structure. For methylene blue solution, N-TiO₂ with 3% H₂O₂ resulted in the greatest absorbance decrease after laser irradiation regardless of wavelength. For stained resin test, N-TiO₂ with 3% H₂O₂ resulted in the greatest color difference after laser irradiation, followed by group that used N-TiO₂ without 3% H₂O₂.

Diagnostic value of BRAF(V600E) mutation analysis in fine needle aspiration for evaluation of thyroid nodules / 고신대학교의과대학학술지

OBJECTIVES: Ultrasound-guided fine-needle aspiration (FNA) is routinely used in the evaluation of thyroid nodules. However, it has several pitfalls, as has been noted in nondiagnostic and indeterminate cases. This study aims to investigate the value of BRAF(V600E) mutation co-testing in FNA cytology. METHOD: A total of 310 patients underwent BRAF(V600E) mutation co-testing in FNA cytology on thyroid nodules between June 2013 and June 2014. Of the 310 patients, 69 patients who had undergone a surgery for thyroid nodules were included in this study. The presence of the BRAF(V600E) mutation was determined by allele-specific polymerase chain reaction amplification of exon 15 of the BRAF gene. RESULTS: Of 69 cases, 33 (47.8%) were BRAF(V600E) mutation positive. The BRAF(V600E) mutation was not significantly associated with high-risk features such as tumor size, lymph node metastasis, and pathological stage. The respective diagnostic performance of FNA (P = 0.02), BRAF(V600E) mutation (P = 0.03), and ultrasonographic (P = 0.00) findings was statistically significant. The sensitivity, specificity and positive predictive value of FNA was 64.9%, 83.3%, and 94.8%. The sensitivity, specificity and positive predictive value of BRAF(V600E) mutation was 56.1%, 91.7%, and 96.9% and the US features was 91.2%, 91.7%, and 98.1% respectively. However, sensitivity of FNA with BRAF(V600E) mutation (77.2%) was lower than FNA with US (92.9%) and combination all together (92.9%). CONCLUSION: In this study, we found that US features were the most useful in preoperative differential diagnosis of thyroid nodules. BRAF(V600E) mutation co-testing in FNA cytology was also useful for diagnosis of thyroid tumors.

Excessive Iodine Status among School-Age Children in Korea: A First Report

BACKGROUND: Korea is considered an iodine sufficient country, and several studies have been conducted regarding iodine status in healthy Korean adults, pregnant women, and preschool children. However, data on iodine status in Korean school-age children are lacking. Therefore, the iodine nutrition status of Korean school-age children was investigated by measuring urine iodine concentration (UIC). METHODS: This cross-sectional study conducted between April and September 2016 comprised 373 school-age children. UIC was determined using a modified microplate method employing ammonium persulfate digestion followed by Sandell-Kolthoff reaction. RESULTS: The median UIC was 458.2 µg/L. Excessive iodine intake (>300 µg/L) was found in 286 children (76.7%), with extremely high values exceeding 1,000 µg/L in 19.6% of subjects. Insufficient iodine intake (<100 µg/L) was observed in eight children (2.1%). UIC values were not significantly different between sexes. CONCLUSION: Korean school-age children showed excessive iodine intake. Therefore, education regarding adequate iodine intake in school-age children is needed.

Expression of the Brother of the Regulator of Imprinted Sites Gene in the Sputum of Patients with Lung Cancer

BACKGROUND: Brother of the regulator of imprinted sites (BORIS) is a putative new oncogene that is classified as a cancer germline gene; however, its role in the development of cancer is unclear. This study investigated the expression of BORIS in lung cancer and its clinical implications. METHODS: The expression of BORIS messenger ribonucleic acid (mRNA) in the sputum of 100 patients with lung cancer (50 with squamous cell carcinoma, 36 with adenocarcinoma, and 14 with small-cell carcinoma) was evaluated by reverse transcription polymerase chain reaction. RESULTS: The overall expression rate of BORIS in patients with lung cancer was 36.0%: 19 of 50 squamous cell carcinomas (38.0%), 13 of 36 adenocarcinomas (36.1%), and 4 of 14 (28.6%) small-cell carcinomas. There was no significant difference in the BORIS expression according to age, gender, or histologic type. However, the mRNA expression of BORIS was significantly related to the pathologic cancer stage (p=0.004) and lymph node metastasis (p=0.001). The expression of the melanoma antigen gene family A1-6 was not associated with the expression of BORIS. CONCLUSION: Our results suggest that the expression of BORIS might be a negative prognostic factor in lung cancers and implicate BORIS as a molecular target for immunotherapy.

A Case of Medullary Thyroid Carcinoma with de novo V804M RET Germline Mutation

Many cases of RET proto-oncogene mutations of hereditary medullary thyroid carcinoma (MTC) have been reported in Korea. However, MTC with V804M RET proto-oncogene germline mutations have not been reported in Korea. A 33-yr-old man was diagnosed with a 0.7-cm sized thyroid nodule. Laboratory testing revealed serum calcitonin was elevated. The patient underwent total thyroidectomy with central compartment neck dissection for the thyroid tumor. RET gene analysis was performed in both the index patient and his family. There were no V804M RET mutation and abnormal laboratory findings within his family except the index patient. Therefore, this patient was a de novo V804M RET germline mutation.

Clinico-pathologic Parameters for Prediction of Microsatellite Instability in Colorectal Cancer / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Although the incidence of microsatellite instability (MSI) accounts for 10-15% of cases of colorectal cancer, its clinical application for all colorectal cancers has widened. We attempted to identify clinical and pathological parameters that may be helpful in selection of patients with MSI-high (MSI-H). MATERIALS AND METHODS: A total of 120 resected colorectal cancers were enrolled retrospectively for this MSI study. Polymerase chain reaction (PCR) and denaturing high performance liquid chromatography and/or real time PCR methods with five markers and immunohistochemistry (IHC) for MLH1 and MSH2 were performed for analysis of cancer and blood specimens. Clinico-pathologic parameters, including IHC, were investigated in order to determine their usefulness as predictive factors of MSI. RESULTS: Among 120 cases of colorectal cancer, MSI was observed in 15 cases (12.5%), including 11 cases of MSI-H and four cases of MSI-low. Patients with MSI were younger, less than 50 years old, had a family history of cancer, Rt. sided colon cancer and/or synchronous multiple colorectal cancer, mucinous histologic type, and serum carcinoembryonic antigen group in the normal range. Results of multivariate analysis showed Bethesda guidelines, Rt. sided and/or synchronous multiple colorectal cancer, and negative expression of IHC for MLH1, which was consistently associated with MSI-H. MSI-H colorectal tumors have met at least one of these three parameters and their sensitivity and specificity were 100% and 72.5%, respectively. CONCLUSION: Bethesda guidelines, tumor location, and negative expression of MLH1 protein are important parameters for selection of patients with colorectal cancers for MSI testing. MSI testing is recommended for patients showing any of these three parameters.

Analysis of TP53 Gene Mutations in the Korean Patients with Lung Cancer

BACKGROUND: Lung cancer is one of the leading causes of cancer-related deaths throughout the world. The gene tumor protein 53 (TP53) is frequently mutated in cases of lung cancer. This study was performed to investigate the frequencies and types of mutations in the TP53 gene in Korean patients with lung cancer. METHODS: We obtained tissue samples from 80 lung cancer patients and synthesized TP53 cDNA by using RNA isolated from these tissues by performing reverse transcriptase polymerase chain reaction. Hybridization and denaturing high-performance liquid chromatography were performed to identify the TP53 gene mutations, and then, the mutations were validated by direct sequencing. RESULTS: Forty mutations out of the 80 patients (50.0%) were noted in the TP53 gene. The frequencies of TP53 gene mutation for different cancer types, namely, squamous cell carcinoma, adenocarcinoma, and small cell carcinoma were 61.1%, 27.3%, and 26.7%, respectively. The mutation frequencies in the different regions of the gene were 10.0% for exon 4, 35.0% for exon 5, 12.5% for exon 6, 22.5% for exon 7, 17.5% for exon 8, and 2.5% for exon 9. The frequently mutated positions were codon 179 in exon 5, codons 202 and 220 in exon 6, and codons 266 and 273 in exon 8. CONCLUSIONS: Exon 5 was the most frequently mutated region in the TP53 gene. Compared to the patients with the other types of cancers, patients with squamous cell carcinoma showed a higher frequency of TP53 mutation. Codon 179 was the most frequently mutated codon in the TP53 gene.

Detection of Rare Cancer Cells in the Blood by RNA Extraction of Filtered Mononuclear Cells and Reverse Transcription-PCR / 임상검사와정도관리

BACKGROUND: To enhance the cancer cell detection rate in blood, we tried to detect cancer cells by blood filtration, RNA extraction and reverse transcription (RT)-PCR in the filtered mononuclear cells (MNCs). METHODS: From the specimens of whole blood and filtered MNCs, RNA was extracted by the guanidinium isothiocyanate buffer method. Filtration efficiency was evaluated by measurement of leukocyte count, red cell count, and hemoglobin level. To compare the RNA extraction efficiency between whole blood and filtered MNCs, the followings were examined: (1) RNA electrophoresis, (2) hTERT, survivin, plakophilin, LunX, and MAGE A1-6 RT-PCR, and (3) the detection limit of added SNU484 cells in the blood by MAGE A1-6 RT-PCR. Finally blood specimens of 13 lung cancer patients were used to detect cancer cells by LunX and MAGE A1-6 RT-PCR with filtered MNCs. RESULTS: The filtration method revealed 0%, 92.8% and 95.1% filtration rates for leukocyte, red cell, and hemoglobin, respectively. Contamination of concentrated genomic DNA was observed in the electrophoresis of RNA extracted from whole blood. Positive rates of hTERT, survivin and plakophilin were higher in the filtered MNCs. The filtration method detected 1 SNU484 cell/mL, and the blood samples of 4 (30.8%) lung cancer patients showed positive results for RT-PCR. CONCLUSIONS: For the detection of cancer cells in the blood, the filtration method was very efficient, and LunX and MAGE A1-6 genes would be useful for the detection of blood cancer cells in patients with lung cancer.