• Biomolecules & Therapeutics
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• v.15 no.4
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• pp.224-229
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• 2007

Depurination, the release of purine bases from nucleosides by hydrolysis of the N-glycosidic bond, gives rise to alterations of the cell genome. Although, cells have evolved mechanisms to repair these lesions, unrepaired apurinic sites have been shown to have two biological consequences: lethality and base substitution errors. 2-Bromopropane (2-BP) is used as an intermediate in the synthesis of pharmaceuticals, dyes, and other organics. In addition, 2-BP has been used as a cleaning solvent in electronics industry. But, 2-BP was found to cause reproductive and hematopoietic disorders in local workers exposed to it. We observed massive depurination after incubation of 2'-deoxyadenosine (dA) and 2'-deoxyguanosine (dG) with the excess amount 2-BP at the physiological condition (pH 7.4, $37^{\circ}C$), which were analyzed by HPLC and LC-MS/MS. In addition, time and dose response relationship of depurination in dA and dG induced by 2-BP at the physiological condition were investigated.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.235-238
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• 2009

In Korea, talc that has been widely used for a lot of consumer products as well as industrial usage until recently was found to be contaminated with asbestos. It becomes a major social issue. Critical health risk about both talc and talc contaminated with asbestos was summarized through literature review. It has been confirmed that talc can pose ovarian cancer when talc powder is used in the genital area. International Agency for Research on Cancer (IARC) already concluded that the perineal use of cosmetic talc can cause possibly carcinogenic to humane(Group 2B), although there was study reporting the lack of a consistent an established correlation between perineal dusting frequency and ovarian tissue talc concentrations and the lack of a consistent dose-response relationship with ovarian cancer risk. The association between talc exposure and ovarian cancer is as strong as in recent studies. The epidemiological studies to date provided inadequate evidence for the carcinogenicity of either inhaled or ingested talc that does not contain asbestos or asbestosiform fibers. Future studies should focus on seeking evidence in talc-exposed populations, collecting reliable information on age at initial used of body powder, exposure assessments related to talc use and dose response relationship in order to identify possible risk of talc ingested or inhaled.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.670-677
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• 2009

The purpose of this study is to reveal the quantitative dose-response relationship between the noise emitted in the platform of subway station and the public response. The noise measured in the platform of subway station was used for a jury test. In order to find the factors which influence annoyance response due to the platform noise, jurors were examined for the difference of the annoying response, interrelation of sound quality parameter and annoyance response. The platform noise level was 77.2$\sim$83.9 dBA and the most of passengers at the platform were highly annoyed. And screen door contributes to annoyance reduction of platform noise. The results from analyzing sound quality parameters shows that loudness and annoyance response have a high correlation coefficient.

• Journal of Environmental Health Sciences
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• v.19 no.3
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• pp.64-73
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• 1993

The study was conducted to investigate the mechanism of tumor promotion as the time courses and the doses of promoter, and the effect of plant fiavonoids on the TPA-induced ODC responses. The results are summarized as follows: 1. A single, toppical application of 17 nmole of the potent tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate, resulted in an induction of mouse epidermal Ornithine Decarboxylase with a peak at 5 hours after treatment and maximized 5.1 times as large as ODC activities of control. 2. Dose-response curve indicated that the tumor promotion increases proportionally between 1.7 and 170 nmole of TPA. This dose dependency relationship indicated that the ability of TPA to stimulate ODC is linked its ability to promote tumors. 3. Naturally occurring plant fiavonoids with anticarcinogenic and antipromotional activities were tested for their abilities to inhibit ODC response induced by skin tumor promoter TPA. Intra peritoneal administration of fiavonoids compounds (rutin, naphthofiavone, baicalein, quercitrin) and herbal drugs (sophorae rios, crataegi fructus, armeniacae semen) inhibited 17 nmole TPA-induced ODC activities in mouse epidermis in vivo.

• Journal of Preventive Medicine and Public Health
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• v.33 no.2
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• pp.165-173
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• 2000

Objectives : To assess the availability of the glycophorin A (GPA) assay to detect the biological effect of ionizing radiation in workers exposed to low-doses of radiation. Methods : Information on confounding factors, such as age and cigarette smoking was obtained on 144 nuclear power plant workers and 32 hospital workers, by a self-administered questionnaire. Information on physical exposure levels was obtained from the registries of radiation exposure monitoring and control at each facility. The GPA mutant assay was performed using the BR6 method with modification by using a FACScan flow cytometer. Results : As confounders, age and cigarette smoking habits showed increasing trends with GPA variants, but these were of no statistical significance. Hospital workers showed a higher frequency of the GPA variant than nuclear power plant workers in terms of the NO variant. Significant dose-response relationships were obtained from in simple and multiple linear regression models. The slope of the regression equation for nuclear power plant workers was much smaller than that of hospital workers. These findings suggest that there may be apparent dose-rate effects. Conclusion : In population exposed to chronic low-dose radiation, the GPA assay has a potential to be used as an effective biologic marker for assessing the bone marrow cumulative exposure dose.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.8
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• pp.4785-4790
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• 2013

Background and Objectives: Evidence for associations between alcohol consumption with breast cancer survival are conflicting, so we conducted the present meta-analysis. Methods: Comprehensive searches were conducted to find cohort studies that evaluated the relationship between alcohol consumption with breast cancer survival. Data were analyzed with meta-analysis software. Results: We included 25 cohort studies. The meta-analysis results showed that alcohol consumption was not associated with increased breast cancer mortality and recurrence after pooling all data from highest versus lowest comparisons. Subgroup analyses showed that pre-diagnostic or post-diagnostic consumpotion, and ER status did not affect the relationship with breast cancer mortality and recurrence. Although the relationships of different alcohol consumption with breast cancer mortality and recurrence were not significant, there seemed to be a dose-response relationship of alcohol consumption with breast cancer mortality and recurrence. Only alcohol consumption of >20 g/d was associated with increased breast cancer mortality, but not with increased breast cancer recurrence. Conclusion: Although our meta-analysis showed alcohol drinking was not associated with increased breast cancer mortality and recurrence, there seemed to be a dose-response relationship of alcohol consumption with breast cancer mortality and recurrence and alcohol consumption of >20 g/d was associated with increased breast cancer mortality.

• Wind and Structures
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• v.14 no.6
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• pp.499-515
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• 2011

Low-frequency building vibration is known to induce symptoms of motion sickness in some occupants. This paper examines how the adoption of a theory of motion sickness, in conjunction with a dose-response model might inform the real-world problem of managing and designing standards for tall building motion sway. Building designers require an understanding of human responses to low-dosage motion that is not adequately considered by research into motion sickness. The traditional framework of Sensory Conflict Theory is contrasted with Postural Instability Theory. The most severe responses to motion (i.e., vomiting) are not experienced by occupants of wind-excited buildings. It is predicted that typical response sets to low-dosage motion (sleepiness and fatigue), which has not previously been measured in occupants of tall-buildings, are experienced by building occupants. These low-dose symptoms may either be masked from observation by the activity of occupants or misattributed to the demands of a typical working day. An investigation of the real-world relationship between building motion and the observation of low-dose motion sickness symptoms and a degradation of workplace performance would quantify these effects and reveal whether a greater focus on designing for occupant comfort is needed.

• Biomolecules & Therapeutics
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• v.8 no.1
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• pp.78-83
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• 2000

The objective of this study was to prevalidate the Organization for Economic Cooperation and Development's (OECD) rodent uterotrophic assay as a test method for screening of potential endocrine disrupting chemicals (EDCs). This study was conducted exactly as described in the OECD protocol documents. A positive control substance, 17$\alpha$-ethinyl estradiol (EE), was administered daily for three days to ovariectomized (OVX) Sprague-Dawley rats at various doses for determine the dose-response curve. Additionally, a pure antiestrogenic chemical, ZM189, 154 was administered to OVX rats at the same time EE to determine the effectiveness of the material against blocking the estrogenic effects of EE. At higher concentration of EE (10 $\mu\textrm{g}$/kg), a statistically significant difference in body weight gain and food consumption was observed compared to vehicle controls. In uterine responses, EE produced a dose-related increase in uterus weights compared to vehicle control. These increases were statistically significant at the >1.0 $\mu\textrm{g}$/kg doses. However, a similar dose-response relationship was not observed in vagina weight. A comparison of the two groups receiving ZM189,154 (0.1 and 1.0 mg/kg) with 0.3 $\mu\textrm{g}$/kg of EE and the group receiving only 0.3 $\mu\textrm{g}$/kg of EE showed dose-related decreases in uterus weights. However, statistical significance was shown in 1.0 mg/kg of ZM189,154. In conclusion, administration of EE produced a dose-related increase in uterine (wet and blotted) weights. Additionally, the 1.0mg/kg dose of ZM189,154 was effective in blocking the estrogenic activity of EE. These data suggest 3-day uterotrophic assay using OVX rats may serve as a good tool for EDCs screening.

• The Korean Journal of Zoology
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• v.18 no.1
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• pp.41-49
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• 1975

Dose response and time dependence of DNA repair synthesis were investigated to determine the possible relationship between DNA repair synthesis and chromosome exchanges in $\\gamma$-ray irradiated BHK-21 and KB cell lines. DNA repair synthesis induced by $\\gamma$-ray was dose dependent up to 5kR, then leveling off occurred until 50 kR was reached. Time dependence of DNA repair synthesis was continued for up to 1$\\sim$2 hours after irradiation although the initial dose responses were cell line specific. Chromosome exchanges induced by $\\gamma$-ray showed different radiosensitivities in these cell lines and did not show a correlation with the DNA repair synthesis.

• YAKHAK HOEJI
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• v.36 no.5
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• pp.449-454
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• 1992

The effect of radioprotective ginseng protein fraction on DNA repair capacity was determined by measuring the amount of $^{3}H-thymidine$ incorporated into DNA in the process of repair synthesis for UV damaged DNA. CHO-Kl cells were prepared whose semiconservative replication was inhibited by trimethylpsoralen plus near-UV(PUVA) treatment. When the cells were exposed to UV light alone, the DNA repair capacity was increased at first and then decreased as UV dose increased. However, when the ginseng fraction was treated to the cells, the DNA repair capacity was kept increasing regardless of UV dose increment. When the concentration of protein contained in the added fraction was increased gradually, the repair capacity was also increased almost linearly showing dose-response relationship of the effect. These results suggest that the enhancement of DNA repair capacity of the cell can be one of the mechanisms of radioprotection by the ginseng fraction.