• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.96-96
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• 2004

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.115-115
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• 2004

• Korean Journal of Veterinary Research
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• v.48 no.4
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• pp.401-411
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• 2008

This study was performed to evaluate repeated-dose oral toxicities of Flos lonicerae extract in Fischer 344/n rats. Flos lonicerae was administered orally to rats at dose levels of 0, 37, 111, 333, 1,000 and 2,000 mg/kg/day. Each group consisted of 10 rats of each gender. The Flos lonicerae extract was given once a day, 5 times a week, for 90 day repeatedly. This study was conducted in accordance with the Protocol of Korea National Toxicology Program and The Standards of Toxicity Study for Medicinal Products. In the present study, there were no toxicologically significant changes in mortality, clinical signs, body weight gains, ophthalmoscopy, urine analysis, hematology, serum biochemistry, necropsy findings, organ weights, histopathology, estrus cycle and sperm examination of all animals treated with Flos lonicerae extract. These results suggest that the oral no observed adverse-effect level of the test item, Flos lonicerae extract, in rats is higher than 2,000 mg/kg/day in both genders. The target organs were not established.

• Korean Journal of Veterinary Research
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• v.49 no.1
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• pp.23-34
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• 2009

This study was performed to evaluate repeated-dose oral toxicities of Chelidonium majus extract in Fischer 344/N rats. Chelidonium majus extract was administered orally to rats at dose levels of 0, 25, 74, 222, 666 and 2,000 mg/kg/day. Each group consisted of 10 rats of each gender. The Chelidonium majus extract was given once a day, 5 times a week, for 90 day repeatedly. This study was conducted in accordance with the Protocol of Korea National Toxicology Program (issued by National Institute of Toxicological Research) and The Standards of Toxicity Study for Medicinal Products (issued by Korea Food and Drug Administration). In the present study, There were no toxicologically significant changes in mortality, clinical signs, body weight gains, ophthalmoscopy, urine analysis, hematology, serum biochemistry, necropsy findings, organ weights, histopathology, estrus cycle and sperm examination of all animals treated with Chelidonium majus extract. These results suggest that the oral no observed adverse-effect level of the test item, Chelidonium majus extract, in rats is higher than 2,000 mg/kg/day in both genders. The target organs were not established.

• Toxicological Research
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• v.21 no.1
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• pp.23-29
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• 2005

A developmental study of CONP01, a new antiarthritic agent, was conducted in Sprague-Dawley rats. Dosage of CONP01 0, 111, 333, and 1000 mg/kg/day were administered to dams orally from day 6 to day 16 of gestation. Two-third of dams per group were subjected to caesarean section on day day 20 of pregnancy for examination of their fetuses, and the remaining one-third of dams per group were allowed to deliver naturally for postnatal examination of their offspring. There was no change in the dams body weights, food consumptions, specific clinical sings and gross findings. There was significant decrease only in the absolute and relative weights of right ovary in 111 mg/kg treatment group, when compared with the vehicle control, whereas other organ weights were not changed. Moreover, no increase in the frequencies of external, visceral and skeletal malformation of fetuses were observed in the treated groups. These results suggest that the oral NOAEL (no observed adverse effect level) of CONP01 may be over 1,000 mg/kg in dams and fetuses of rats.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2753-2758
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• 2014

Background: GC-binding factor 2 (GCF2) is a transcriptional regulator that represses transcriptional activity of the epidermal growth factor receptor (EGFR) by binding to a specific GC-rich sequence in the EGFR gene promoter. In addition to this function, GCF2 has also been identified as a tumor-associated antigen and regarded as a potentially valuable serum biomarker for early human hepatocellular carcinoma (HCC) diagnosis. GCF2 is high expressed in most HCC tissues and cell lines including HepG2. This study focused on the influence of GCF2 on cell proliferation and apoptosis in HepG2 cells. Materials and Methods: GCF2 expression at both mRNA and protein levels in HepG2 cells was detected with reverse transcription (RT) PCR and Western blotting, respectively. RNA interference (RNAi) technology was used to knock down GCF2 mRNA and protein expression. Afterwards, cell viability was analyzed with a Cell Counting Kit-8 (CCK-8), and cell apoptosis and caspase 3 activity by flow cytometry and with a Caspase 3 Activity Kit, respectively. Results: Specific down-regulation of GCF2 expression caused cell growth inhibition, and increased apoptosis and caspase 3 activity in HepG2 cells. Conclusions: These primary results suggest that GCF2 may influence cell proliferation and apoptosis in HepG2 cells, and also provides a molecular basis for further investigation into the possible mechanism at proliferation and apoptosis in HCC.

• Journal of Neurogastroenterology and Motility
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• v.24 no.4
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• pp.678-680
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• 2018

• Biomolecules & Therapeutics
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• v.22 no.4
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• pp.267-274
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• 2014

Drug development and preclinical trials are challenging processes and more than 80% to 90% of drug candidates fail to gain approval from the United States Food and Drug Administration. Predictive and efficient tools are required to discover high quality targets and increase the probability of success in the process of new drug development. One such solution to the challenges faced in the development of new drugs and combination therapies is the use of low-cost and experimentally manageable in vivo animal models. Since the 1980's, scientists have been able to genetically modify the mouse genome by removing or replacing a specific gene, which has improved the identification and validation of target genes of interest. Now genetically engineered mouse models (GEMMs) are widely used and have proved to be a powerful tool in drug discovery processes. This review particularly covers recent fascinating technologies for drug discovery and preclinical trials, targeted transgenesis and RNAi mouse, including application and combination of inducible system. Improvements in technologies and the development of new GEMMs are expected to guide future applications of these models to drug discovery and preclinical trials.

• The Journal of Korean Academic Society of Nursing Education
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• v.21 no.1
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• pp.75-85
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• 2015

Purpose: The purpose of this study was to investigate the effects of preclinical clinical performance examination (CPX) on nursing students' confidence in their nursing skills and critical thinking competence. Methods: The design of this research was one-group pretest-posttest, and the participants were 112 nursing students. The preclinical CPX consisted of a clinical examination, patient-nurse relationship, oral test of related knowledge, written test of the nursing process, and debriefing using comprehensive scenarios based on real patient cases. The confidence of nursing skills consisted of an 8-item NRS and the critical thinking competence consisted of a 12-item 4-point scale developed by researchers and measured in both the pretest and posttest. The collected data were analyzed using paired t-tests, ANOVA, and Pearson correlation coefficients. Results: The score for confidence in nursing skills (t=10.60, p<.001) and that for critical thinking competence (t=7.03, p<.001) increased significantly after preclinical CPX. Conclusion: This study showed that preclinical CPX was effective in improving nursing students' confidence in their nursing skills and critical thinking competence. Therefore, preclinical CPX is expected to be utilized in nursing practice education. Additional studies including those on control groups are recommended to compare differences between the preclinical CPX group and control group.

• Progress in Medical Physics
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• v.34 no.3
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• pp.33-39
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• 2023

Purpose: FLASH radiotherapy (RT) using ultra-high dose rate (>40 Gy/s) radiation is being studied worldwide. However, experimental studies such as preclinical studies using small animals are difficult to perform due to the limited availability of irradiation devices and methods for generating a FLASH beam. In this paper, we report the initial dosimetry results of a prototype electron linear accelerator (LINAC)-based irradiation system to perform ultra-high dose rate (UHDR) preclinical experiments. Methods: The present study used the prototype electron LINAC developed by the Research Center of Dongnam Institute of Radiological and Medical Sciences (DIRAMS) in Korea. We investigated the beam current dependence of the depth dose to determine the optimal beam current for preclinical experiments. The dose rate in the UHDR region was measured by film dosimetry. Results: Depth dose measurements showed that the optimal beam current for preclinical experiments was approximately 33 mA, corresponding to a mean energy of 4.4 MeV. Additionally, the average dose rates of 80.4 Gy/s and 162.0 Gy/s at a source-to-phantom surface distance of 30 cm were obtained at pulse repetition frequencies of 100 Hz and 200 Hz, respectively. The dose per pulse and instantaneous dose rate were estimated to be approximately 0.80 Gy and 3.8×10⁵ Gy/s, respectively. Conclusions: Film dosimetry verified the appropriate dose rates to perform FLASH RT preclinical studies using the developed electron-beam irradiator. However, further research on the development of innovative beam monitoring systems and stabilization of the accelerator beam is required.