• Journal of radiological science and technology
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• v.27 no.2
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• pp.21-27
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• 2004

This study was conducted to estimate absorbed radiation doses associated with CT examinations. We compared CT dose index between single detector CT and multi detector CT. To establish radiation dose criteria in CT examination in Korea, we measured radiation dose for CT examinations in Seoul and kyungki-do. The results obtained were as follows ; 1. Averaged CTDIW value per 100 mAs was $13.5{\pm}3.2\;mGy$, and ranged from 8.1 mGy to 19.1 mGy in head phantom, was $7.1{\pm}2.0\;mGy$, and ranged from 3.7 mGy to 10.9 mGy in body phantom. 2. CTDIW was 3.2 mGy(1.26 times) larger in multi detector CT than single detector CT in head phantom, and 2.1 mGy(1.34 times) larger in body phantom. 3. The dose was the highest in 4 channel multi detector CT, and followed 8 channel multi detector CT, 16 channel multi detector CT and single detector CT in head phantom. And the dose was the highest in 4 channel and 8 channel multi detector CT, and followed 16 channel multi detector CT and single detector CT in body phantom.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.976-982
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• 2008

The 10 species of marine green algae was collected from Jejudo(Island) in Korea. Methanolic and aqueous extracts were prepared and screened for inhibition activities against tumor cell growth. Of the tested samples, the sea staghorn (Codium fragile) aqueous extract (CFAE) showed the highest activity on CT-26 cell growth. Therefore, CFAE was selected for further experiments and the possibility to induce apoptosis by the CFAE was investigated. Flow cytometric analysis revealed that it dose-dependently increased apoptotic cells with hypodiploid DNA contents in CT-26 cell line. These results indicated that CFAE can suppress the growth of CT-26 cells through apoptosis. The CFAE decreased the protein expression of anti-apoptotic Bcl-xL and led to the activation of caspase-3 and -7. A crude polysaccharide was separated from CFAE and it mainly constituted with 61.2% galactose and 30.5% arabinose as analyzed by high performance liquid chromatography (HPLC).

• Biomedical Science Letters
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• v.27 no.4
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• pp.329-333
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• 2021

We previously identified that tumor cells genetically modified with a 4-1BBL co-stimulatory molecule had anticancer effects in a CT26 mouse colorectal tumor model. To identify the distinction between immune cells in a mouse tumor model treated with tumor cells genetically modified with 4-1BBL or β-gal, we examined the immune cells in CT26-WT, CT26-βgal, and CT26-4-1BBL tumor bearing mice 21 days after tumor cell administration. The CD8+ T cells population in mice treated with tumor cells genetically modified with 4-1BBL was significantly increased on day 21 compared to that of tumor cells genetically modified with β-gal in the spleen and tumor tissue. The CD4+ T cell population was not different between the two mice groups. The Foxp3+CD25^high CD4 T cell population decreased on day 21 in tumor tissues, but the decrease was not significant. We also found that CD8 T cells had pivotal roles in inhibiting tumor growth by treating mice with ant-CD4 and CD8 antibodies. These results suggest that tumor cells genetically modified with 4-1BBL could inhibit tumor growth by affecting on CD8 T lymphocytes.

• Journal of Korean Medicine Rehabilitation
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• v.26 no.3
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• pp.51-58
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• 2016

Objectives This study was designed to investigate whether the Cheongajihwang-Tang (CT) has an inhibitory effect association with oxidation or inflammation in RAW264.7 cells. Methods Cytotoxic activity of CT extract on RAW264.7 cells was evaluated by using 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) solution. Nitric oxide production was measured using Griess reagent system. The total phenolic contents and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was measured to evaluate the anti-oxidative effects of CT. Dichlorofluorescin diacetate (DCFH-DA) has been used as a substrate for measuring intracellular oxidant production. Results Cheongajihwang-Tang does not impair the cell viability in tested concentration. CT showed anti-oxidative effects in vitro by decreasing electron donating ability, and also showed anti-inflammatory effects suppressing NO and ROS expression in LPS induced RAW264.7 activation. CT inhibited the generation of intracellular ROS production as dose dependant manner. Conclusions CT has anti-oxidative effects and anti-inflammatory activities. These results indicate that CT extract has an anti-inflammatory activities via anti-oxidative effects.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4543-4548
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• 2015

Background: To investigate the effects of ASMase mediated endothelial cell apoptosis in multiple hypofractionated irradiations in CT26 tumor bearing mice. Materials and Methods: Thirty-five CT26 tumor bearing mice were subjected to single ionizing radiation (IR) of 0, 3, 6, 9, 12, 15, 18 Gy. Eight hours after IR, the mice were sacrificed and tumor tissues were used for CD31 immunohistochemistry staining, TUNEL and CD31 double staining, ASMase activity assay. Then 6 and 12 Gy were chosen for multiple hypofractionated IR experiments according to the above results. Each time after IR, 5 mice were sacrificed and assayed as above. Results: The ASMase activities were increased significantly after a single IR of 12 Gy or higher which was accompanied with remarkable increased endothelial cell apoptosis and decreased MVD. For 6 Gy which was not high enough to trigger ASMase activation, after 2 or more times of IR, the ASMase activities were significantly increased accompanied with remarkable increased endothelial cell apoptosis and decreased MVD. While for 12 Gy, after 2 or more times of IR, the ASMase activities and endothelial cell apoptosis rates were maintained without remarkable increase; however, the MVD was significantly decreased. What's more, the cancer cell apoptosis rates were significantly increased after multiple IR for both 6 Gy and 12 Gy. Conclusions: ASMase mediated endothelial cell apoptosis may play an important role in the process of multiple hypofractionated IR for CT26 colorectal carcinoma.

• Biomedical Science Letters
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• v.21 no.1
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• pp.23-31
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• 2015

Recently, specific antibodies have been used extensively to diagnose and treat various diseases. It is essential to assess the efficacy and specificity of antibodies, especially the in vivo environment. Anti-HER-2/neu mAb was evaluated as a possible transporting agent for radioimmunotherapy. The monoclonal antibody was successfully radio-labeled with $^{131}I$. In vitro binding assays were performed to confirm its targeting ability using another radio-iodine, $^{125}I$. Binding percentage of $^{125}I$ labeled anti-HER-2/neu mAb in HER-2/neu expressing CT-26 cells was found to be 4.5%, whereas the binding percentage of $^{125}I$ labeled anti-HER-2/neu mAb in wild-type CT-26 was only 0.45%. In vivo images were obtained and analyzed through $\gamma$-camera and an optical fluorescent modality, IVIS-200. $\gamma$-camera images showed that $^{131}I$ labeled anti-HER-2/neu mAb accumulated in HER-2/neu CT-26 tumors. Optical imaging based on near infrared fluorescence labeled anti-HER-2/neu mAb showed higher fluorescence intensities in HER-2/neu CT-26 tumors than in wild-type CT-26 tumors. Anti-HER-2/neu mAb was found to specifically bind to its receptor expressing tumor. Our study demonstrates that in vivo imaging technique is a useful method for the evaluation of an antibody's therapeutic and diagnostic potentials.

• Molecules and Cells
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• v.42 no.12
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• pp.869-883
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• 2019

Interleukin (IL)-15 is an essential immune-modulator with high potential for use in cancer treatment. Natural IL-15 has a low biological potency because of its short half-life and difficulties in mass-production. IL-15Rα, a member of the IL-15 receptor complex, is famous for its high affinity to IL-15 and its ability to lengthen the half-life of IL-15. We have double-transfected IL-15 and its truncated receptor IL-15Rα into CT26 colon cancer cells to target them for intracellular assembly. The secreted IL-15:IL-15Rα complexes were confirmed in ELISA and Co-IP experiments. IL-15:IL-15Rα secreting clones showed a higher anti-tumor effect than IL-15 secreting clones. Furthermore, we also evaluated the vaccine and therapeutic efficacy of the whole cancer-cell vaccine using mitomycin C (MMC)-treated IL-15:IL-15Rα secreting CT26 clones. Three sets of experiments were evaluated; (1) therapeutics, (2) vaccination, and (3) long-term protection. Wild-type CT26-bearing mice treated with a single dose of MMC-inactivated secreted IL-15:IL-15Rα clones prolonged survival compared to the control group. Survival of MMC-inactivated IL-15:IL-15Rα clone-vaccinated mice (without any further adjuvant) exceeded up to 100%. This protection effect even lasted for at least three months after the immunization. Secreted IL-15:IL-15Rα clones challenging trigger anti-tumor response via CD4⁺ T, CD8⁺ T, and natural killer (NK) cell-dependent cytotoxicity. Our result suggested that cell-based vaccine secreting IL-15:IL-15Rα, may offer the new tools for immunotherapy to treat cancer.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.207-213
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• 2006

Purpose: This study was performed to evaluate the usefulness of computed tomography (CT) gastrography in the surgical management of a gastric gastrointestinal stromal tumor (GIST). Materials and Methods: We retrospectively analyzed the clinicopathologic data of 38 patients who had undergone CT gastrography from among patients who had gastric GISTS surgically resected at the Department of Surgery, Seoul National University Hospital, between January 2001 and February 2006. We compared CT gastrography data, including tumor size and location and distance from the gastroesophageal junction or pylorus with endoscopic, surgical and pathologic findings. Results: The longitudinal tumor locations on CT gastrography and endoscopy were identical to the surgical findings. For tumor sizes on CT gastrography of less than 5 cm, we performed 11 (42.3%) laparoscopic wedge resections from among 26 cases. In the 12 cases with tumor sizes of 5 cm or over, only 1 (8.3%) laparoscopic wedge resection was performed. When the tumor was located in the middle third of the stomach, a laparoscopic wedge resection was performed in 88.9% (8/9) of the cases, but when it was located in the upper or lower third, a laparoscopic wedge resection was performed in only 13.8% (4/29) of the cases. Conclusion: Three-dimensional information from CT gastrography allows the surgeon to perform preoperative planning, including accurate localization.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.336-343
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• 2010

Coronary artery CT angiography has short scanning length, the exposure dose is high. Therefore, it is required to study on the organ dose when using MDCT. We compared the differences between the absorbed dose and effective dose in the major organs assessing the absorbed dose in the major organs by 16-MDCT and 64-MDCT in the subjects with coronary artery CT angiography, the same protocol by 16-MDCT and 64-MDCT. As a result, the great orders of absorbed dose when conducting coronary artery CT angiography had been shown as heart, stomach, liver, pancreas, kidney, spleen, large intestine, lung, small intestine, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.538{\pm}0.026(Mean{\pm}SD,\;p<0.05)mGy{\sim}71.316{\pm}4.316mGy$ in 16-MDCT, and heart, stomach, pancreas, spleen, liver, kidney, small intestine, large intestine, lung, thyroid gland, ovary, bladder, and orbit with the absorbed dose distribution of $0.87{\pm}0.01mGy{\sim}115.26{\pm}1.59mGy$ in 64-MDCT, demonstrating some different distributions. The exposed doses to the patient per one time scanning with coronary artery CT angiography were $71.316{\pm}4.316mGy$ in 16-MDCT as the absorbed dose based on the heart and $115.26{\pm}1.59mGy$ in 64-MDCT. The effective doses were 7.41 mSv and 12.11 mSv in 16 and 64-MDCT, respectively. Taking into account the results of brain CT with 2.8 mSv that has comparatively large scanning length and size, facial CT 0.8 mSv, chest CT 5.7 mSv, pelvic CT 7.2 mSv, and abdominal and pelvic CT 14.4 mSv, it is very high considering the scanning length of 13 cm limited to the heart for the scanning range.

• Journal of Technology Innovation
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• v.15 no.1
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• pp.1-26
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• 2007

This study's purpose is to promote the development of CT industry by analizing the causal relationship between technology factor and commercialization of Tech. in CT SMEs and Ventures. The result is that Only technology experience accumulation among technical factors(technology develpoment cost, technology experience accumulation, technology concentration, technical expertise) has a significant effect on commercialization success or failure and non-technical factors have not a significant effect on.