• Toxicological Research
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• v.16 no.4
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• pp.302-309
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• 2000

The purpose of this study is to investigate toxic effects of iso-butylalcohol (iBA) in Sprague-Dawley (SD) rats under the exposure of 6 hours a day, 5 days a week for 13 weeks by inhalation, and to evaluate the occupational safety of iBA in comparison with the permissible exposure level (PEL) stipulated by the Occupational Safety and Health Administration (OSHA). iBA did not induce any abnormal changes from the aspects of clinical signs, feed consumption, ophthalmic test, urinalysis, hematology and blood chemistry during and at the terminal of the inhalation toxicity tests. We did not find any abnormal findings in the gross and microscopic observations due to the inhalation of iBA. There was no alteration in relative organ weights by the inhalation of iBA. No observed adverse effect level (NOAEL) of iBA was considered to be more than 3,000 ppm in rats under the inhalation of 6 hours a day, 5 days a week for 13 weeks. Fifty ppm of iBA, the PEL regulated by OSHA, is too conservative for working places. As iBA showed no abnormal observations in all the experimental parameters at any concentration under this experimental condition, we suggest that 150 ppm is safe enough for the PEL of iBA in the working areas, even taking into onsideration that OSHA lowered the PEL to 50 ppm for fear of the probable risk of its skin irritation.

• Safety and Health at Work
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• v.2 no.1
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• pp.34-38
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• 2011

Objectives: The antimicrobial activity of silver nanoparticles has resulted in their widespread use in many consumer products. Yet, despite their many advantages, it is also important to determine whether silver nanoparticles may represent a hazard to the environment and human health. Methods: Thus, to evaluate the genotoxic potential of silver nanoparticles, in vivo genotoxicity testing (OECD 474, in vivo micronuclei test) was conducted after exposing male and female Sprague-Dawley rats to silver nanoparticles by inhalation for 90 days according to OECD test guideline 413 (Subchronic Inhalation Toxicity: 90 Day Study) with a good laboratory practice system. The rats were exposed to silver nanoparticles (18 nm diameter) at concentrations of $0.7\;{\times}\;10^6$ particles/$cm^3$ (low dose), $1.4\;{\times}\;10^6$ particles/$cm^3$ (middle dose), and $2.9\;{\times}\;10^6$ particles/$cm^3$ (high dose) for 6 hr/day in an inhalation chamber for 90 days. The rats were killed 24 hr after the last administration, then the femurs were removed and the bone marrow collected and evaluated for micronucleus induction. Results: There were no statistically significant differences in the micronucleated polychromatic erythrocytes or in the ratio of polychromatic erythrocytes among the total erythrocytes after silver nanoparticle exposure when compared with the control. Conclusion: The present results suggest that exposure to silver nanoparticles by inhalation for 90 days does not induce genetic toxicity in male and female rat bone marrow in vivo.

• Toxicological Research
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• v.31 no.1
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• pp.69-75
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• 2015

The objective of this study was to investigate the toxicological information of freeze-dried powder from Allomyrina dichotoma (A. dichotoma) larvae as a food ingredient. The powder, suspended in distilled water, was administered once daily by oral gavage to four groups of Sprague-Dawley (SD) rats at dose levels of 0 (vehicle control), 250, 850, and 2500 mg/kg/day. After 13 wks of repeated administration, the standard toxicological parameters such as mortality, clinical signs, body weight, food consumption, ophthalmologic examination, clinical pathology, organ weights and macro/microscopic examination were applied for assessment of general toxicity. In addition, serum IgE and histamine levels were determined to evaluate allergenicity. The freeze-dried powder from A. dichotoma larvae did not produce treatment-related changes or findings in any toxicological parameters in either sex of any dosed groups except for slight increases in serum histamine levels at 2500 mg/kg/day. The changes were considered not to be adverse since the magnitude was minimal. In conclusion, the NOAEL (No Observed Adverse Effect Level) of the freeze-dried powder from A. dichotoma larvae was determined to be 2500 mg/kg/day or more in both sexes of SD rats and it is considered a candidate to be edible material.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.2
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• pp.73-81
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• 2011

The purpose of this study was to obtain scientific information regarding classification and health hazards that may result from a 13 weeks inhalation exposure of isoprene in Sprague-Dawley (SD) rats. The testing method was conducted in accordance with OECD guidelines for the testing of chemicals No. 413. The Rats were divided into 4 groups (10 male and 10 female rats in each group) and exposed to 0, 360, 1,620, 7,300 ppm isoprene in each exposure chamber for 6 h/day, 5 days/week, for 13 weeks. As a result, there were no mortality or abnormality during the period of study and did not show any significant changes of body weight. There were no dose response changes in urinalysis, hematological and serum biochemical value examination. Relative organ weight was increased significantly the right kidney in 7,300 ppm group of male rats. In female rats, relative organ weight of the left kidney and the both lungs in 1,620 ppm group and the left lung and the both kidneys in 7,300 ppm group were increased significantly. But the histopathological findings did not reveal any exposure-related changes. According to the above results, the no observable adverse effect level (NOAEL) of isoprene was 7,300 ppm (20.3 mg/L) in both male and female rats. In conclusion, Isoprene was not classified specific target organ toxicity of the 'Standard for Classification and Labeling of Chemical Substance and Material Safety Data Sheet' (Ministry of Employment and Labor, 2009).

• The Korea Journal of Herbology
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• v.28 no.1
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• pp.15-21
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• 2013

Objectives : To evaluate the safety of KOB, a polyherbal medicine for allergic rhinitis, we conducted a subchronic toxicology study. Methods : Dried extract of KOB(Lot. No. 11003, yield : 41.1%) was prepared from GLP company (Hanpoong Pharm & Food Co., Ltd). KOB was repeatedly administrated orally of male SD rats at daily dose levels of 500 (G2), 1250 (G3) and 5000 (G4) mg/kg/day for 13 weeks. We recorded the clinical signs of toxicity, body weight, food intake/consumption, optometry, urine analysis, organ weights, hematology, and conducted serum biochemical analysis, necropsy, gross and histological changes in target organs of Sprague-Dawley rats, and clinical chemistry analysis. Results : Neither death nor any toxicological signs were obserbed in KOB at all doses of 500, 1250 and 5000 mg/kg/day during the administration period for thirteen-week. Furthermore, there was no difference in body weight and food-take consumption, optometry, necropsy, organ weight, gross pathological findings, and urine analysis among the groups of rats treated with different doses of KOB, during at the observation period for thirteen-week. The hematological analysis and clinical blood chemistry data were revealed no toxic effects from repeated-dose administration of KOB in rats during the observation period. Conclusions : Based on these results, the no observable adverse effect level (NOAEL) of KOB was considered to be 5000 mg/kg/day for male rats under these study conditions.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.218-229
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• 2011

Lepimectin is a insecticide agent. In order to register this new pesticide, the series of toxicity data on animal testing were reviwed to evaluate its hazards to consumers and to determine its acceptable daily intake. Lepimectin was mostly excreted by feces. It has low acute oral toxicity while it has no dermal, ocular irritation and skin sensitization (As the result of subchronic, chronic toxicity and carcinogenicity showed changes of hematology and clinical biochemistry parameter of serum and blood.). Two-generation reproduction toxicity, genotoxicity, carcinogenicity and prenatal development toxicity were not proven. Therefore, the ADI for Lepimectin is 0.02 mg/kg/ bw/day, based on the NOAEL of 2.02 mg/kg/ bw/day of two-years carcinogenic toxicity study in rats and applying an uncertainty factor of 100.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.208-217
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• 2011

Pyrimisulfan is a herbicide. In order to register this new pesticide, the series of toxicity data on animal testing were reviewed to evaluate its hazards to consumers and also to determine its acceptable daily intake. Pyrimisulfan was excreted mostly by feces. It has low acute oral toxicity while it has no dermal, ocular irritation and skin sensitization (As the result of subchronic and chronic toxicity and carcinogenicity showed changes of hematology and liver.). Two-generation reproduction toxicity, genotoxicity, carcinogenicity and prenatal development toxicity were not proven. Therefore, the ADI for Pyrimisulfan is 0.1 mg/kg/ bw/day, based on the NOAEL of 10 mg/kg/ bw/day of 90-days repeated dose oral toxicity study in dogs while applying an uncertainty factor of 100.

• Toxicological Research
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• v.23 no.4
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• pp.363-371
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• 2007

Isaria sinelairii (IS) was orally administered at doses of 0, 0.04, 0.2, and 1 g/kg/day over a 13-week period. There were no observed clinical signs or deaths related to treatment in all the groups tested. Therefore, the approximate lethal oral dose of I. sinclairii was considered to be higher than 1 g/kg in rats. Throughout the administration periods, no significant changes in diet consumption, ophthalmologic findings, organ weight, clinical pathology (hematology, clinical chemistry, coagulation, and urinalysis) or gross pathology were detected. Minor changes were found in hematological parameters for the 0.04 g/kg/day and 0.2 g/kg/day IS treated groups (triglyceride reductions of $20.1{\sim}46.6%$ and platelet increases), but all changes were within physiological range. Microscopic examination failed to identify any treatment-related histopathologic changes in the organs of the IS-treated rats other than nuclear enlargement (cellular atypia) of the tubular regions in the medulla of the kidney in the high dose group. From these results, one can conclude that the no-observed effect level (NOAEL) of I. sinclairii is less than 0.04 g/kg/day in rats.

• Journal of Microbiology and Biotechnology
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• v.32 no.1
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• pp.46-55
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• 2022

Clostridioides difficile infection (CDI) is a significant cause of hospital-acquired and antibiotic-mediated intestinal diseases and is a growing global public health concern. Overuse of antibiotics and their effect on normal intestinal flora has increased the incidence and severity of infections. Thus, the development of new, effective, and safe treatment options is a high priority. Here, we report a new probiotic strain, Bacillus amyloliquefaciens (BA PMC-80), and its in vitro/in vivo anti-C. difficile effect as a prospective novel candidate for replacing conventional antibiotics. BA PMC-80 showed a significant anti-C. difficile effect in coculture assay, and its cell-free supernatant (CFS) also exhibited a considerable anti-C. difficile effect with an 89.06 ㎍/ml 50% minimal inhibitory concentration (MIC) in broth microdilution assay. The CFS was stable and equally functional under different pHs, heat, and proteinase treatments. It also exhibited a high sensitivity against current antibiotics and no toxicity in subchronic toxicity testing in hamsters. Finally, BA PMC-80 showed a moderate effect in a hamster CDI model with reduced infection severity and delayed death. However, further studies are required to optimize the treatment condition of the hamster CDI model for better efficacy and identify the antimicrobial compound produced by BA PMC-80.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.3
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• pp.233-244
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• 2006

Of many volatile organic detergents for metals, benzine(CAS No. 8030-30-6), of which the toxicity has not yet been proven, has been used as an alternative of the halide compounds in the consideration of toxic effects, global warming and the destruction of ozone layer. In order to evaluate the effects of the benzine on human body by investigating the subchronic inhalation toxicity, to obtain the basic data for establishing the criteria of exposure in working environments and to classify the hazardousness in compliance with the Industrial Safety and Health Act by evaluating the hazardousness, repeated inhalation exposure test was carried with SD rats. The rats were grouped by 10 females and males each. The repetitive inhalation exposures were carried out at 4 levels of concentration of 0 ppm, 60 ppm, 300 ppm, and 1,500 ppm, for 6 hours a day, 5 days a week, for 13 weeks. The results are described hereunder. 1. No death of the animals of the exposed and controlled groups in the test period. Not any specific clinical symptoms, change in feed intake quantity, abnormality in eye test, or change in activity were observed. 2. In the 300 ppm and 1,500 ppm groups, weight reduction in the female groups and weight increase of liver and kidney in the male groups compared with control group were observed with statistical significance(p<0.05). 3. In the blood test, the HCT increased in the male 300 ppm group and the number of hematocyte increased, MCV and MCH decreased in the male 1,500 ppm group. In the female 1,500 ppm group, the HB decreased and the distribution width of the hematocyte particle size increased. In the blood biochemistry test, the TP in the male 1,500 ppm group and the LDH in the female 1,500 ppm group were increased with statistical significance(p<0.05). 4. Under the test conditions of the present study with SD rats, the NOEL was evaluated to be from 60 ppm to 300 ppm for both male and female groups. By extrapolation, the NOEL for human who work 8 hours a day was evaluated to be from 128 ppm to 640 ppm 5. Since the NOEL evaluated in this study do not exceed 60ppm(0.184 mg/L) the test material does not belong to the classification of the hazardous substance "NOEL${\leq}$0.5mg/L/6hr/90day(rat), for continuous inhalation of 6hours a day for 90 days" nor to the basic hazardous chemical substance class 1(0.2 mg/L/6hr/90day(rat) defined by the GHS which is a criteria of classification and identification of chemical compounds. However, considering the boiling point($30-204^{\circ}C$), flashing point($-40^{\circ}C$), vapor pressure(40 mmHg), and the inflammable range(1.0 - 6.0 %), sufficient care should be taken for handling in the safety aspects including fire or explosion.