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Toxicity and Carcinogenicity of Dichlorodiphenyltrichloroethane (DDT)

  • Harada, Takanori;Takeda, Makio;Kojima, Sayuri;Tomiyama, Naruto
    • Toxicological Research
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    • v.32 no.1
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    • pp.21-33
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    • 2016
  • Dichlorodiphenyltrichloroethane (DDT) is still used in certain areas of tropics and subtropics to control malaria and other insect-transmitted diseases. DDT and its metabolites have been extensively studied for their toxicity and carcinogenicity in animals and humans and shown to have an endocrine disrupting potential affecting reproductive system although the effects may vary among animal species in correlation with exposure levels. Epidemiologic studies revealed either positive or negative associations between exposure to DDT and tumor development, but there has been no clear evidence that DDT causes cancer in humans. In experimental animals, tumor induction by DDT has been shown in the liver, lung, and adrenals. The mechanisms of hepatic tumor development by DDT have been studied in rats and mice. DDT is known as a non-genotoxic hepatocarcinogen and has been shown to induce microsomal enzymes through activation of constitutive androstane receptor (CAR) and to inhibit gap junctional intercellular communication (GJIC) in the rodent liver. The results from our previously conducted 4-week and 2-year feeding studies of p,p'-DDT in F344 rats indicate that DDT may induce hepatocellular eosinophilic foci as a result of oxidative DNA damage and leads them to hepatic neoplasia in combination with its mitogenic activity and inhibitory effect on GJIC. Oxidative stress could be a key factor in hepatocarcinogenesis by DDT.

Effect of Cigarette Smoke Exposure on MPTP-Induced Neurotoxicity in Mice (흡연이 MPTP에 의해 유발되는 신경독성에 미치는 영향)

  • Heung-Bin Lim;Hyung-Ok Sohn;Young-Gu Lee;Dong-Wook Lee
    • Journal of the Korean Society of Tobacco Science
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    • v.18 no.2
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    • pp.160-169
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    • 1996
  • Effect of cigarette smoke exposure on 1-methyl-4-phpnyl-1,2,3,6-tetrahydro-pyidine (Mm)-induced neurotoxicity was investigated in C57BL6 mice. Cigarette smoke exposure of mice to the mainstream smoke generated from 15 cigarettes for 10 mins per day, 5 days per week, for fi weeks, effectively attenuated the decline both in the level of striatal dopamine and the number of brrosine hydros:ylase-positive ceils in the brain caused by MPTP treahent. Exposure to cigarette smoke significantly decreased monoamine oxidate B activity in the cerebral cortex and cerebellum. The activity of brain antioxidant enzymes such as catalase, glutathione peroxidase, and Cu, Zn-superoxide dismutase, was not changed by cigarette smoke exposure or MPTP treatment. Sulfhydryl compounds content in all brain regions except for the striatum was uniquely increased by MPTP treatment, however, such an effect of MPTP was not observed in mice exposed to cigarette smoke. These results suggest that cigarette smoke exposure inhibits MPTP-induced neurotoxicity without influencing free radical metabolism in the brain of mice. This protective effect of cigarette smoke seems to be closely related with the decreased activity of brain monoamine oxidase H. Key words : cigarette smoke exposure, dopamine, monoamine oxidase B, antioxidant enzywles, MPTP.

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Purification and Serology of Potato Virus S (감자 바이러스 S의 순화와 항혈청제조)

  • Lee Soon Hyung;Lee Key Woon;Chung Bong Jo
    • Korean journal of applied entomology
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    • v.16 no.3 s.32
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    • pp.145-148
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    • 1977
  • he study was conducted to produce an antiserum of potato virus S for identification and screening of seed-potatoes. Potato virus S was isolated from infected plants and identified by means of indicator plants and electro microscopy. Isolated potato virus S was multiplied in Nicotiana deebneyii and the virus was purified by a modified method that was developed through this study. The purity of potato virus S was 1.18mg/ml. Purified potato virus S was injected into rabbit intravenously once a week for 5 weeks. Antiserum was collected 10 days after the last injection. The produced antiserum was determined to have a titer of, 1/2048 by means of microprecipitin tests.

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Study on the Effect of SGHHT on Hyperlipidemia (순기활혈탕(順氣活血湯)이 고지혈증(高脂血症)에 미치는 영향(影響))

  • Lee, Ki-Seo;Kang, Tak-Lim;Namgung, Uk;Kim, Dong-Hee
    • Journal of Haehwa Medicine
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    • v.13 no.2
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    • pp.97-107
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    • 2004
  • As a long-term goal for the development of new prescriptions for hyperlipidemia, SGHHT was examined in the present study using a rat model in which the hyperlipidemia was induced. The major parameters related to lipid metabolism were investigated and the key findings are summarized below. 1. The body weight of hyperlipidemia-induced rats began to show lower body weight beginning one week after SGHHT treatment compared to non-treated control group animals. 2. Cholesterol levels showed a significant decrease beginning three weeks after SGHHT treatment, compared to hyperlipidemia-induced control group. 3. Total cholesterol levels in SGHHT-treated animal group were significantly decreased compared to the hyperlipidemia-induced control group. 4. Glucose levels in SGHHT-treated animal group were significantly decreased compared to the hyperlipidemia-induced control group. 5. Triglyceride levels in SGHHT-treated animal group were significantly decreased compared to the hyperlipidemia-induced control group.6. SGOT levels in SGHHT-treated animal group were significantly decreased compared to the hyperlipidemia-induced control group whereas there was no significant change in SGPT levels. 7. HDL-cholesterol levels were significantly increased in SGHHT- treated animal group compared to the hyperlipidemia-induced control group. 8. LDL-cholesterol levels were significantly decreased in SGHHT-treated animal group compared to the hyperlidemia-induced control group.

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The Analysis of Risk Factor Management Programs for Patients with Coronary Artery Disease (관상동맥질환자를 위한 위험요인관리 프로그램 분석)

  • Bang, So-Youn;Park, Mi-Young
    • The Korean Journal of Rehabilitation Nursing
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    • v.16 no.1
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    • pp.27-36
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    • 2013
  • Purpose: This study was performed to analyse the trends of risk factor management programs for patients with coronary artery disease. Methods: Using PubMed, 35 intervention studies related to risk factor management programs among randomized controlled trials searched with the key words of coronary artery disease and coronary heart disease. Collected studies were analysed according to the characteristics of studies and participants, method and content of intervention, and outcome indicator and its effects. Results: The mean period of intervention was $28.7{\pm}26.8$ weeks, the mean frequency was $3.0{\pm}2.0$ times per week, and the duration of one session was below 60 minuets in 65.8% of the reviewed studies. The interventions were counselling, exercise, education, and cognitive behavior therapy. Counselling was applied most frequently in previous studies. The outcomes of intervention had been measured with anthropometric, physical, physiological, psychological, behavioral, and cognitive aspects, but the effect of the intervention was inconsistent among the studies. Conclusion: Based on the results of this study, systematic and comprehensive cardiac rehabilitation program consisted of counselling, exercise, and education should be developed and performed for health management and relapse prevention of patients with coronary artery disease.

Effects of Cadmium on Heat Shock Protein Induction and on Clinical Indices in Rats (카드뮴이 랫드의 Heat Shock Protein 발현에 미치는 영향과 독성학적 변화에 관한 연구)

  • 김판기
    • Journal of Environmental Health Sciences
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    • v.22 no.4
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    • pp.91-101
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    • 1996
  • Exposure indices are important tools which enable scientists to reliably predict and detect exposures to xenobiotics and resultant cell injury. Since the de novo synthesis of stress proteins can be detected early after exposure to some agents, analysis of toxicant-induced changes in gene expression, i.e. alterations in patterns of protein synthesis, may be useful to develop as biomarkers of exposure and toxicity. The acute and chronic effects of cadmium(Cd, $CdCl_2$ 20 mg/kg) on Wistar male rats were evaluated concerning cadmium contents, tissues enzyme activity, HSP expression. The results of the study were as follows: 1. Less cadmium was absorbed through the digestive tracts, but the ratio of contents in renal to hepatic cadmium was higher at 8 weeks after treatment. 2. ALT(alanine aminotransferase), AST(aspartate aminotransferase), glucose, BUN(blood urea nitrogen), creatinine, the key indices of the clinical changes in hepatic and renal function were significantly changed by the cadmium treatment after 1 week in liver, after 4 weeks in kidney. 3. Enhanced synthesis of 70 KDa relative molecular mass proteins were detected in 2 hours after cadmium exposure, with maximum activity occurring at 8~48 hours. Induction of $HSP_{70}$ was evident at proximal tubules and glomeruli in kidney. Testicular cells produced enough HSP to be detected normally. From the above results, it could be concluded that $HSP_{70}$ induction by the cadmium treatment was a rapid reaction to indicate the exposure of xenobiotics.

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The Job Seekers Model: Comparison of the General Search Model and the Unified Approach Model

  • LEE, Dong-Hae;LEE, Sang-Ki
    • The Journal of Industrial Distribution & Business
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    • v.12 no.1
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    • pp.7-13
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    • 2021
  • Purpose: Unemployment in its general form is a result stemming from the decisions of workers to search for a new and better paying job. In this study, the view that unemployed workers were not simply desiring any job, but one that would maximize their expected future outcome, was examined. Research design, data, and methodology: In order for collection of data and analysis, the panel dates of individual applications for job openings on job search websites were utilized to examine search effort and period for individuals. Results: It was found that the number of applications sent by a job seeker declined over their period of job searching, and that job seekers over a long duration of time tend to send relatively more applications per week throughout their entire search period. The latter finding contradicts the implications of the standard labor search effort models. Conclusions: It can be observed that these job search models fail to capture several key elements in search efforts, and that the search time for an offer is not entirely predetermined by the labor market conditions and socio-economic (individual) characteristics of the searcher. It can be shortened as he or she intensifies their job search efforts.

Indonesian plastic surgeons' attitude during early period of the COVID-19 pandemic

  • Prasetyono, Theddeus Octavianus Hari
    • Archives of Craniofacial Surgery
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    • v.22 no.1
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    • pp.17-25
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    • 2021
  • Background: This study aims to report how the practice of plastic surgeons and their attitude was during the first measure period of coronavirus disease 2019 (COVID-19) pandemic. Methods: A survey study was held among members of the Indonesian Association of Plastic Reconstructive and Aesthetic Surgeons during week 5 after the first report of COVID-19. A 10 multiple-choice questions (MCQs) and 1 essay covered key questions on the area of surgery and operating room, clinics, internal meeting, and consultation. The only open-ended question relates to the last MCQ addresses a future "flipped" medical practice. Results: Response rate was 45.6% among 228 members, with 89.4% did no practice or limited their service to emergency and urgent cases only. Only 1.9% kept their official meeting as usual, while the majority modified it. The practice in the operating theatre and clinic were also altered to comply with the measures; with 21.2% from the total respondents only allowed patients with exposure to come for visit after taking 14 days of self-quarantine. Teleconsultation was practiced by 50% of the respondents, while 41.3% agreed and 10.6% disagreed upon the future "flipped" medical practice. Conclusion: In general plastic surgeons have made supportive actions during the pandemic. Surgery was performed with all precautions at the utmost as a reflection of high alert of viral infection. Teleconsultation has been embraced via existing social media. Agreement upon the future "flipped" medical practice is reasonable. All in all, the actions were considered as most relevant.

Nutritional status and related factors among ethnic preschool children in Northern Thailand: a cross-sectional study

  • Janpeang, Jantip;Suwannapoom, Chatmongkon;Anukunwathaka, Natnaree
    • Child Health Nursing Research
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    • v.28 no.3
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    • pp.176-186
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    • 2022
  • Purpose: This study investigated the nutritional status of ethnic (belonging to minority groups) preschool children in Northern Thailand. Methods: In this cross-sectional descriptive study, the sample group included 147 parents and 147 preschool children (2-6 years old). Participants volunteered to complete a questionnaire on the personal information of children and parents, as well as family- and school-related factors. Data were analyzed using descriptive statistics, a nutritional status calculator, and logistic regression analysis. Results: A birth weight of less than 2,500 g was related to weight-for-age and weight-for-height. Not having been breastfed and having been breastfed for less than 6 months were related to weight-for-height. An elementary school education level among parents was related to children's height-for-age. Familial unhealthy food consumption for 1-2 days per week was related to weight-for-age and height-for-age. Conclusion: This study reflects the importance of nutritional care for children at the beginning of pregnancy and continuing to the preschool age, as well as the importance of breastfeeding. Families were found to be a key factor in supporting good nutrition among children.

Analysis of Aluminum Stress-induced Differentially Expressed Proteins in Alfalfa Roots Using Proteomic Approach

  • Kim, Dong-Hyun;Lee, Joon-Woo;Min, Chang-Woo;Rahman, Md. Atikur;Kim, Yong-Goo;Lee, Byung-Hyun
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.42 no.3
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    • pp.137-145
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    • 2022
  • Aluminum (Al) is one of the major factors adversely affects crop growth and productivity in acidic soils. In this study, the effect of Al on plants in soil was investigated by comparing the protein expression profiles of alfalfa roots exposed to Al stress treatment. Two-week-old alfalfa seedlings were exposed to Al stress treatment at pH 4.0. Total protein was extracted from alfalfa root tissue and analyzed by two-dimensional gel electrophoresis combined with MALDI-TOF/TOF mass spectrometry. A total of 45 proteins differentially expressed in Al stress-treated alfalfa root tissues were identified, of which 28 were up-regulated and 17 were down-regulated. Of the differentially expressed proteins, 7 representative proteins were further confirmed for transcript accumulation by RT-PCR analysis. The identified proteins were involved in several functional categories including disease/defense (24%), energy (22%), protein destination (9%), metabolism (7%), transcription (5%), secondary metabolism (4%), and ambiguous classification (29%). The identification of key candidate genes induced by Al in alfalfa roots will be useful to elucidate the molecular mechanisms of Al stress tolerance in alfalfa plants.