• Journal of Digestive Cancer Research
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• v.8 no.2
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• pp.97-101
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• 2020

Metformin is a widely used first-line anti-diabetic drug worldwide. Epidemiologic studies using the large population-based cohort database have shown the association between metformin uses and reduced risk of various type cancers including gastric cancer. In the gastric cancer prevention, metformin use was associated with the significant reduction of gastric cancer risk, especially for long-term metformin users. However, there is no well-designed randomized controlled clinical trial investigating the effect of metformin as a chemopreventive drug for gastric cancer. Therefore, further well-designed clinical trials will be needed to implement metformin for chemoprevention of gastric cancer.

• Journal of Korean Academy of Nursing
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• v.29 no.1
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• pp.150-160
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• 1999

Background and purpose : Drug abuse is one of the most serious problems among the Korean adolescents today and has been associated with delinquent behavior in adolescents. The number of adolescents who abuse drugs is increasing yearly. Solutions to the problem, however, have not been well developed. The purpose of this study was to determine the effectiveness of a drug use prevention program which was developed by researchers. The program was a modified DARE(Drug Abuse Resistance Education) program for Korean adolescents. Methods: This study used an experimental, one-group pretest-posttest design with a convenience sample of 122 middle school students who were at one middle school located in Seoul. Data were collected using a self-administered questionnaire where ‘knowledge and attitude about drug use’, ‘social skill’, and ‘self-esteem’ were measured. The program had 12 sessions to improve knowledge and attitudes towards drugs, decision making skills, social resistance skills, management of stress and self-esteem of students. Teaching strategies for each session were varied lectures, group discussion. role-playing, question-and-answer sessions and audiovisual materials. Paired t-test was used to analyze the differences between the pre- and post-test scores on knowledge of and attitudes towards drug use, social skills, and self-esteem. Results : There were significant differences in knowledge and attitudes about drug use between pretest and post-test (p＜.05), but no significant differences in social skill and self-esteem(p＞.05). Conclusion: Our results showed that the drug use prevention program was not effective in promoting social-skill and self-esteem of Korean adolescents. These findings might be due to the respondents being in the period of early adolescence (puberty) and not being good at group discussion. So, further study is needed to develop a drug use prevention program appropriate to students 9 and 10 years old, and to encourge small group discussion.

• Journal of The Korean Society of Clinical Toxicology
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• v.13 no.2
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• pp.95-102
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• 2015

Purpose: Drug overdose is easily found in the emergency department (ED). Sedative-hypnotics overdose causes the aspiration pneumonia in patients with decreased mental status. The purpose of this study was to investigate the risk factors of aspiration pneumonia in patients poisoned with sedative-hypnotics. Methods: One hundred seventy eight patients who were poisoned with sedative-hypnotics and who visited ED between 2009 and 2015 were included. This study was conducted retrospectively, with collection of data by review of medical records. We collected the data concerning the characteristics of patients and classified them into two groups based on the development of aspiration pneumonia. Logistic regression analysis was performed to investigate the factors for the development of aspiration pneumonia. Results: Thirty five patients had an aspiration pneumonia during their hospital stay in 178 patients. The age, amount of ingestion, Glasgow Coma Scale (GCS) score at admission, a history of hypertension and diabetes mellitus, and the hypotension at admission were significantly different between two groups in univariate analysis. The age, amount of ingestion and GCS score at admission were associated with the development of aspiration pneumonia in the multivariate logistic regression analysis (OR 1.028 (95%CI, 1.002-1.056, p=0.037), 1.026 (95%CI, 1.004-1.043, p=0.001), 0.737 (95%CI, 0.683-0.915, p=0.002)). All patients with aspiration pneumonia were discharged without a sequelae. Conclusion: The development of aspiration pneumonia in the patients of sedative-hypnotics overdose is associated with old age, amount of drug ingestion, and GCS score at admission.

• Natural Product Sciences
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• v.18 no.4
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• pp.239-243
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• 2012

Mushrooms have a long history of use in traditional medicine, and hundreds of novel constituents in mushrooms with miraculous biological properties have been identified recently. Although diverse effects for medicinal use of mushrooms such as anticancer activity are proven, their reversal activities of drug resistance in cancer cells was rarely reported so far. In the search for novel medicinal use of mushrooms, we tested the multidrug resistance (MDR) reversal activities of diverse mushrooms collected from Korea. Among, the mushroom extracts tested, Cantharellus cibarius (M02) and Russula emetica (M12) revealed MDR reversal activities of paclitaxel in the P-glycoprotein (Pgp)-positive HCT15 and MES-SA/dX5 cancer cells, but not in the Pgp-negative A549 and MES-SA cancer cells. In addition, these mushrooms also enhanced the cytotoxicity of doxorubicin, another well-kwown Pgp-associated anticancer drug against MES-SA/DX5 cells, but not against MES-SA cells. Meanwhile, the cytotoxicity of cisplatin, a well-known Pgp-non-associated anticancer drug, was not affected by the mushrooms all the cells tested. From these results, we suspected that some ingredients of M02 and M12 have Pgp-associated MDR reversal activities.

• Toxicological Research
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• v.28 no.2
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• pp.73-79
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• 2012

While the ability to develop nanomaterials and incorporate them into products is advancing rapidly worldwide, understanding of the potential health safety effects of nanomaterials has proceeded at a much slower pace. Since 2008, Korea Food and Drug Administration (KFDA) started an investigation to prepare "Strategic Action Plan" to evaluate safety and nano risk management associated with foods, drugs, medical devices and cosmetics using nano-scale materials. Although there are some studies related to potential risk of nanomaterials, physical-chemical characterization of nanomaterials is not clear yet and these do not offer enough information due to their limitations. Their uncertainties make it impossible to determine whether nanomaterials are actually hazardous to human. According to the above mention, we have some problems to conduct the human exposure risk assessment currently. On the other hand, uncertainty about safety may lead to polarized public debate and to businesses unwillingness for further nanotechnology investigation. Therefore, the criteria and methods to assess possible adverse effects of nanomaterials have been vigorously taken into consideration by many international organizations: the World Health Organization, the Organization for Economic and Commercial Development and the European Commission. The object of this study was to develop risk assessment principles for safety management of future nanoproducts and also to identify areas of research to strengthen risk assessment for nanomaterials. The research roadmaps which were proposed in this study will be helpful to fill up the current gaps in knowledge relevant nano risk assessment.

• YAKHAK HOEJI
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• v.42 no.3
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• pp.336-344
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• 1998

Effects of ochratoxin A (OTA) on embryo development were studied in cultured whole embryos from 9.5 day gestation rat for 48 h. OTA (more than $0.5{\mu}g/ml$) induced microcephaly in the cultured rat whole embryos. Protein and DNA content, and DNA synthesis were significantly inhibited by OTA. We next examined whether the microcephaly seen in cultured whole embryo partially results from inhibition of differentiation of embryonic midbrain cells. Embryonic midbrain cells were extracted from 12 day gestation rat embryos, and cultured for 96 hr. OTA ibhibited cell differentiation about 50% over control. We also tested whether OTA-induced embryotoxicity would be associated with oxidative damages. We measured the ${\gamma}$-glutamyltranspeptidase (${\gamma}$-GT) and glutathione peroxidase (GPX) activities, and glutathione (GSH) content in both cultured whole embryos and embryonic midbrain cells. OTA decreased GSH content, whereas slightly increased ${\gamma}$-GT activity, but GPX activity was not significantly changed. These results show that OTA caused the microcephaly and its effect may be partially due to the inhibition of cell differentiation of embryonic midbrain cells, but the role of oxidative damages is not clear in embryotoxicity.

• Journal of Environmental Health Sciences
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• v.36 no.2
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• pp.155-162
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• 2010

Aflatoxin $B_1$, a known human carcinogen, is the member of aflatoxin subfamily that is most frequently found in contaminated foods. Epidemiological studies have suggested that aflatoxins may be associated with human liver cancer and acute hepatitis. Recently it was reported that the traditional medical herbs sold in domestic markets are contaminated with aflatoxins. Long-term administration of these contaminated medicines could result in adverse health effects. Therefore, it is important to evaluate the levels of exposure to aflatoxin in people who ingest traditional herbal medicines. Blood samples were collected, before and after the herbal medicine intake, from 151 subjects who visited the hospital. The metabolite of aflatoxin $B_1$ in blood, aflatoxin $B_1$-albumin (aflatoxin $B_1$-lysine), is reportedly an appropriate internal exposure indicator, and its levels in the collected bloods were therefore analyzed using a liquid chromatography-mass spectrometry. The analytical method of aflatoxin $B_1$-lysine in blood was firstly optimized in Korea and the levels were detected below quantification limits (2 pg/mg albumin) in this study population. Consequently, the exposure levels of aflatoxin $B_1$ by ingestion of herbal medicines were low but it is important to monitor routinely due to the possibility of risk on the aflatoxin exposure.

• Korean Journal of Health Education and Promotion
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• v.22 no.2
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• pp.125-139
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• 2005

Objectives: More than half of youth smokers start to use cigarettes in their middle-school ages. Thus, middle school students should be the primary target population for smoking prevention education although the technical smoking rate is higher in high school students than in middle school students. Based on this significance, this study examined personal and social factors reinforcing non-smoking middle school students to acquire positive attitudes on smoking cigarettes. Methods: A total of 1,081 students of the 3 middle schools in Seoul participated in the self-administered survey. The designated schools were conveniently selected and all the 2nd-grade students of the schools participated in the survey. The questionnaire asked reinforcing social factors of smoking such as, family and parental history of drug use, close-people's smoking and drug use, personal experience of drug use, perceived smoking and drug use knowledge and attitudes, perceived smoking intention in future, and other delinquent behaviors. Results: Personal experience of drug and delinquent behaviors, perceived smoking intention in future, perceived knowledge of smoking, educational experience, and close-people's smoking and drug use were significantly related to students' attitudes on smoking. The significant factors affecting the positive attitudes of smoking were living with broken family and few education experience of smoking in school as social factors and strong smoking intention in future, high score of delinquent behavior, and low score of drug use knowledge as personal factors. Conclusions: Adolescents' strong smoking intention and little smoking education experience would primary personal and social factors reinforcing positive attitudes on smoking. Thus, school-based educational programs preventing smoking intention need to be developed and to be delivered to middle school students to minimize the future smoking population in a long-term perspective.

• Biomolecules & Therapeutics
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• v.18 no.4
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• pp.448-453
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• 2010

Drug-induced long QT syndrome is known to be associated with the onset of torsades de pointes (TdP), resulting in a fatal ventricular arrhythmia. QT interval prolongation can result from blocking the human ether-a-go-go-related gene (hERG) channel, which is important for the repolarization of cardiac action potential. Nicardipine, a Ca-channel blocker and antihypertensive agent, has been reported to increase the risk of occasional serious ventricular arrhythmias. We studied the effects of nicardipine on hERG $K^+$ channels expressed in HEK293 cells and Xenopus oocytes. The cardiac electrophysiological effect of nicardipine was also investigated in this study. Our results revealed that nicardipine dose-dependently decreased the tail current of the hERG channel expressed in HEK293 cells with an $IC_{50}$ of 0.43 ${\mu}M$. On the other hand, nicardipine did not affect hERG channel trafficking. Taken together, nicardipine inhibits the hERG channel by the mechanism of short-term channel blocking. Two S6 domain mutations, Y652A and F656A, partially attenuated (Y652A) or abolished (F656A) the hERG current blockade, suggesting that nicardipine blocks the hERG channel at the pore of the channel.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.2
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• pp.68-74
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• 2023

Objectives: Drug holidays are suggested to reduce the formation of osteonecrosis in patients under intravenous (IV) bisphosphonates (BPs) therapy. The objectives of this study are to evaluate the incidence of medication-related osteonecrosis of the jaw (MRONJ) following tooth extraction in cancer patients using IV BP, and to assess the effect of drug holiday on the development of MRONJ. Patients and Methods: A manuel search of the patient folders of Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Hacettepe University was undertaken to identify cancer patients who used IV BPs and had at least one tooth extraction between 2012 and 2022. Patents' age, sex, systemic condition, the type of BP used, duration of BP used, number of tooth extraction, duration of drug holiday, localization of tooth extraction and incidence of MRONJ were recorded. Results: One hundred nine teeth were removed from 57 jaws in 51 patients. All tooth extractions were performed under perioperative antibiotic prophylaxis and with primary wound closure. The incidence of MRONJ was 5.3%. Stage 1 MRONJ developed in 3 patients (only one had a drug holiday). The median duration of drug holiday was 2 months. No significant difference between the patients with and without a drug holiday and MRONJ development was found (P=0.315). The mean age of patients developed MRONJ was 40.33±8.08 years. A statistically significant difference was found between age and MRONJ development (P=0.002). Conclusion: The effect of a short-term drug holiday on the development of MRONJ may be limited because BPs remain in bone tissue for a long time. Drug holidays should be applied with the approval of an oncologist with other preventive measurements.