Min-Gu Kang

Occupational Safety and Health Research Institute, Bucheon, Gyeonggi Province, South Korea

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Publications (8)5.69 Total impact

  • Jong-Kyu Kim · Soo-Jin Kim · Min-Gu Kang · Se-Wook Song

    No preview · Article · Sep 2014
  • Jong-Kyu Kim · Min-Gu Kang · Soo-Jin Kim · Se-Wook Song

    No preview · Article · Sep 2014
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    ABSTRACT: Carbon black is classified as carcinogen group 2B by International Agency for Research on Cancer (IARC). But it uncertained the effects of ultrafine carbon black particles on oxidative damage or inflammation. So we were focused to evaluate the oxidative damage or inflammation with ultrafine carbon black particles at gene expression level by using mouse macrophage cell line, and the co-effects with solvent coating to it. It was evaluated the changes of gene expression with real time RT-PCR, and oxidative DNA damage with Fragment Length Analysis with Restriction Enzyme (FLARE) assay in mouse macrophage (RAW264.7) cell line. Two kinds of carbon black induced the gene expression of cytokines related to acute inflammation, and with 0.1% methylcyclohexane coating were regulated conversely each other. The oxidative DNA damage with smaller size carbon black was increased than bigger one (the range with 500–30 nm). The 0.1% methylcyclohexane increased the damage by binding with each carbon black (the dose range with 100 ng/mL-100 μg/mL). In this study, we got the conclusion that the genotoxicity of carbon blacks are elevated with its size get smaller and their surface area wider, and with methylcyclohexane coating. It could cause DNA damage by promoting oxidative stress and inflammatory responses.
    Full-text · Article · Dec 2012 · Molecular and Cellular Toxicology
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    ABSTRACT: We sought to establish a novel method to generate nano-sized carbon black particles (nano-CBPs) with an average size smaller than 100 nm for examining the inhalation exposure risks of experimental rats. We also tested the effect of nano-CBPs on the pulmonary and circulatory systems. We used chemical vapor deposition (CVD) without the addition of any additives to generate nano-CBPs with a particle size (electrical mobility diameter) of less than 100nm to examine the effects of inhalation exposure. Nano-CBPs were applied to a nose-only inhalation chamber system for studying the inhalation toxicity in rats. The effect on the lungs and circulatory system was determined according to the degree of inflammation as quantified by bronchoalveolar lavage fluid (BALF). The functional alteration of the hemostatic and vasomotor activities was measured by plasma coagulation, platelet activity, contraction and relaxation of blood vessels. Nano-CBPs were generated in the range of 83.3-87.9 nm. Rats were exposed for 4 hour/day, 5 days/week for 4 weeks to 4.2 × 10(6), 6.2 × 10(5), and 1.3 × 10(5) particles/cm(3). Exposure of nano-CBPs by inhalation resulted in minimal pulmonary inflammation and did not appear to damage the lung tissue. In addition, there was no significant effect on blood functions, such as plasma coagulation and platelet aggregation, or on vasomotor function. We successfully generated nano-CBPs in the range of 83.3-87.9 nm at a maximum concentration of 4.2 × 10(6) particles/cm(3) in a nose-only inhalation chamber system. This reliable method can be useful to investigate the biological and toxicological effects of inhalation exposure to nano-CBPs on experimental rats.
    Full-text · Article · Sep 2011 · Safety and Health at Work
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    ABSTRACT: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.
    Preview · Article · Sep 2011 · Safety and Health at Work
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    ABSTRACT: We investigated the genotoxicity of two chemicals, methyl formate and 2-methylbutane, using male ICR mice bone marrow cells for the screening of micronucleus induction. Although these two chemicals have already been tested numerous times, a micronucleus test has not been conducted and the amounts used have recently been increased. 7 week male ICR mice were tested at dosages of 250, 500, and 1,000 mg/kg for methyl formate and 500, 1,000, and 2,000 mg/kg for 2-methlybutane, respectively. After 24 hours of oral administration with the two chemicals, the mice were sacrificed and their bone marrow cells were prepared for smearing slides. As a result of counting the micronucleated polychromatic erythrocyte (MNPCE) of 2,000 polychromatic erythrocytes, all treated groups expressed no statistically significant increase of MNPCE compared to the negative control group. There were no clinical signs related with the oral exposure of these two chemicals. It was concluded that the two chemicals did not induce micronucleus in the bone marrow cells of ICR mice, and there was no direct proportion with dosage. These results indicate that the two chemicals have no mutagenic potential under each study condition.
    Full-text · Article · Sep 2010 · Safety and Health at Work
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    ABSTRACT: The subchronic toxicity of sec-butanethiol was investigated in Sprague-Dawley rats following a 13-week period of repeated inhalation exposure. Four groups of 10 rats of each sex were exposed to sec-butanethiol vapor by whole-body inhalation at 0, 25, 100, or 400 ppm for 6 h per day, 5 days a week over a 13-week period. At 400 ppm, both genders exhibited a decrease in food consumption, although a decrease in the body weight gain was only observed in females. Hematological investigations revealed a decrease in red blood cell, hemoglobin, and hematocrit in both the male and female groups, whilst the female group exhibited an increase in the mean corpuscular volume and a decrease in the mean corpuscular hemoglobin concentration. There was an increase in kidney weight for both genders but the liver weight was only higher in males than controls. Histopathological alterations were found in the kidneys, spleen, and nasal olfactory epithelium. There were no treatment-related effects observed in both genders at 100 ppm. Under the present experimental conditions, the target organs were determined to be the blood cells, the kidneys, the liver, and the nasal turbinates in rats. The no-observed-effect level was considered to be 100 ppm in rats.
    Full-text · Article · Jul 2009 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
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    ABSTRACT: Although manganese (Mn) has been shown to increase prolactin (PRL) by decreasing dopamine (DA) in the hypothalamus, the mechanism of Mn-induced regulation of the hypothalamic-hypophyseal-pituitary axis is unclear. We assessed the effects of inhaled Mn on hypothalamic DA and pituitary PRL production and evaluated the role of pituitary-specific transacting factor 1 (Pit-1), a transacting factor of PRL gene, in Mn-induced changes in PRL secretion in the rat brain. Male rats exposed to Mn for 4 or 13 weeks (1.5 mg/m3, 6 h/day, 5 days/week) showed a progressive and significant decrease in hypothalamic DA, whereas PRL and Pit-1 mRNA levels increased in response to Mn exposure. These results suggest that exposure to Mn decreases hypothalamic DA and promotes the production of PRL in the pituitary and that Pit-1 might be a regulator of DA and PRL.
    No preview · Article · Feb 2009 · Neuroreport
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    ABSTRACT: Male Sprague-Dawley rats were exposed to a water-soluble metal working fluid (MWF) (5% v/v) contaminated with endotoxins (10,000 eu/ml or 100,000 eu/ml) at 10 mg/m3 for six hours per day for three days (acute exposure) or two weeks (subacute exposure). The geometric mean diameter of the MWF aerosols was 1.56 μm, and the airborne endotoxin concentrations ranged from 1,231 to 2,173 eu/m3 (10,000 eu/ml in the bulk MWF) for the low dose and 19,263–27,386 eu/m3 (100,000 eu/ml in the bulk MWF) for the high dose. Minimal effects were observed after exposure to 10 mg/m3 of the MWF without endotoxins for three days or two weeks. However, an increase in the number of polymorphonuclear cells (PMNs) and the level of protein was noted in the bronchoalveolar lavage (BAL) fluid from the rats acutely exposed to the MWF with endotoxins. The acute exposure produced a greater increase in the number of PMNs and total cell number in the BAL fluid than the subacute exposure. The number of white blood cells in the peripheral blood and the weight of the lungs both increased after the subacute exposure to the MWF aerosol with endotoxins, indicating increased vascular permeability in response to the endotoxin exposure. The levels of cyotokines such as IL-4, INF-γ, and IL-1β in the BAL fluid from the rats exposed to the MWF with or without endotoxins remained unchanged. Although the level of nitric oxide (NOx ) in the BAL supernatant did not show any change, the induction of NOx from the alveolar macrophages increased in the rats acutely or subacutely exposed to the MWF contaminated with endotoxins. The ConA-induced proliferation response showed no change, yet the LPS-induced proliferation response was significantly increased in the splenocytes from the rats subacutely exposed to the MWF with and without endotoxins. The level of TNF-α in the spleen cell culture obtained from the rats exposed to the MWF with or without endotoxins increased without changing the levels of IL-1β, IL-4, and INF-γ. The level of endotoxin-specific IgE in the serum obtained from the rats exposed to the MWF with endotoxins increased dose-dependently, while the levels of total immunoglobulins (IgG1, IgG2a and IgE) and endotoxin-specific IgG1 and IgG2a remained unchanged. Accordingly, the current results indicate that lung inflammation can be immediately induced by acute or subacute exposure to an MWF contaminated with endotoxins, and macrophages would appear to play a role in the induction of inflammation along with B-cell functions rather than T-cell functions, after subacute exposure to an MWF with endotoxins. In addition, endotoxin-specific IgE is an early marker for endotoxin exposure in the workplace.
    No preview · Article · Jul 2005 · Archive für Toxikologie
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    ABSTRACT: Rats were exposed for 6 h per day in inhalation chambers to a 10 mg/m(3) concentration of metalworking fluid (MWF) contaminated with endotoxin at concentrations of 1813 (low dose) and 20,250 eu/m(3) (high dose) 5 days per week for 8 weeks. It was found that 94.7% of the MWF aerosol particles had diameters in the range of 0.42-4.6 microm, with geometric mean diameter of 1.56 microm. The body weight and pulmonary function parameters were measured every week during the 8 weeks of exposure, whereas bronchoalveolar lavage (BAL) fluid was prepared to measure the inflammatory markers and cytokines after the 8 weeks of exposure. There were no changes in body weight and respiratory function (tidal volume and respiratory frequency) during the 8 weeks of exposure to the MWF containing endotoxins, yet lung weight increased significantly (P < 0.05) in the rats exposed to the MWF both with and without endotoxins. The number of polymorphonuclear (PMN) cells in the BAL fluid increased significantly (P < 0.05) in the rats exposed to MWF with endotoxins, and the levels of cytokines such as IL-4, INF-gamma, IL-1beta, and TNF-alpha also were significantly increased (P < 0.05) compared to the control. The NOx production activity of the BAL cells increased significantly (P < 0.05) in the rats exposed to the MWF with and without endotoxins. Increases in lung weight, number of PMN cells, and levels of extracellular cytokines and NOx were all more significant in the rats exposed to the MWF with endotoxins rather than in those exposed to MWF without endotoxins. In spleen cell cultures, T-cell proliferation activity was decreased, yet cytokine levels (INF-gamma, IL-1beta, IL-4, and TNF-alpha) remained unchanged after repeated exposure to MWF with and without endotoxins. Although the levels of total IgG(1), IgG(2a), and IgE antibodies in the serum were not changed, the levels of endotoxin-specific antibodies, including IgG(2a) and IgE, were increased significantly (P < 0.05) in the rats exposed to endotoxins, but there was not a significant increase in endotoxin-specific IgG(1). When taken together, the results indicate that lung inflammatory responses can be induced without changing pulmonary function after repeated exposure to MWFs contaminated with endotoxins. In addition, endotoxin-specific IgG(2a) and IgE may be effective biomarkers for workers exposed to MWFs contaminated with endotoxins in the workplace.
    No preview · Article · Apr 2005 · Environmental Toxicology