Effects of Toluene, Xylene and Trichloroethylene on the Regulation of GnRH, GnRH Receptor and Pit-1 Gene Expression in Male Rat Hypothalamus and Pituitary / 대한산업의학회지

The workplace exposure of chemicals has steadily increased, therefore the concern for subsequent effect on reproductive outcome has been an important issue in occupational medicine. In previous studies, higher rates of spontaneous abortion, reduced fertility and menstrual disorder among women, and an impairment of sperm quantity and quality among men have been associated with a wide variety of chemical agents. This study was conducted to evaluate the effects of toluene, xylene and trichloroethylene (TCE) injection on the mRNA levels of GnRH, GnRH receptor and Pit-1 genes in male rats hypothalamus and pituitary and the effects on the plasma levels of FSH, LH, prolactin and testosterone. Sprague-Dawley male rats were divided into five groups of five each according to concentration of toluene, xylene and TCE. The rats were injected subcutaneously to 0, 50, 100, 200, 400 mg/kg body weight/day of toluene, xylene and TCE, respectively for 6 days. Rat brains were excised and hypothalamus and pituitary were separated. Reverse transcription-polymerase chain reaction (RT-PCR) and RNase protection assay (RPA) were used to evaluate the GnRH, GnRH receptor and Pit-1 mRNA levels. Plasma concentrations of FSH, LH, prolactin and testosterone were assayed by radioimulunoassay (RIA). The results were as follows; 1. GnRH, GnRH receptor and Pit-1 mRNA levels in toluene and xylene injected groups, and GnRH receptor mRNA levels in TCE injected group were lowered dose-dependently. Especially, GnRH receptor and Pit-1 mRNA levels in 200 mg/kg of toluene injected group, and GnRH, GnRH receptor and Pit-1 mRNA levels in 400 mg/kg of toluene injected group were significantly lowed than control group (p<0.05). GnRH receptor and Pit-1 mRNA levels in 400 mg/kg of xylene injected group, and GnRH receptor mRNA levels in 400 mg/kg of TCE injected group were significantly lower than control group (p<0.05). 2. The plasma levels of prolactin and testosterone in 400 mg/kg of toluene injected group, and LH in 100, 200 and 400 mg/kg of xylene injected group, and testosterone in 400 mg/kg of TCE injected group were significantly lower than control group (p<0.05). In conclusion, we speculated that toluene and xylene affected reproductive system secondarily through hypothalamus-pituitary axis, and TCE affected directly through steroidogenesis. And we recomended that further study for assessment of the reproductive toxiclty of mixed organic solvent exposures should be conducted.

Effects of Mercury Chloride on Nitric Oxide Syntheses in Mouse Peritoneal Macrophage and EMT-6 Cell / 예방의학회지

The effects of treatment with mercury chloride on the nitrite and nitrate syntheses were observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium(DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, and 3-fold of those measured after 12 hours respectively. There were very close associations between the amounts of nitrite and nitrate measured in the culture media according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. ATP synthesis also decreased in EMT-6 cells by mercury chloride. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of ATP synthesis.

Effect of Mercury Chloride on Peritoneal Macrophage or EMT-6 cell from Balb/c mice / 대한산업의학회지

The effect of treatment of mercury chloride on the nitrite and nitrate synthesis was observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, and 3-fold of those measured after 12 hours respectively. There were very close associations between the amounts of nitrite and nitrate measured in the culture media, according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of metabolism of cells.

Effect of Mercury Chloride on Peritoneal Macrophage or EMT-6 cell from Balb/c mice / 대한산업의학회지

The effect of treatment of mercury chloride on the nitrite and nitrate synthesis was observed in peritoneal macrophages from Balb/c mice and EMT-6 cells in vitro. The cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with cytokines. Amounts of nitrite and nitrate in the culture media after 24 and 36 hours of culture were about 2-fold, and 3-fold of those measured after 12 hours respectively. There were very close associations between the amounts of nitrite and nitrate measured in the culture media, according to culture time. The survival rate of peritoneal macrophages was significantly decreased by mercury chloride added into the media in dose-dependent manner, however the survivals of EMT-6 cells were not influenced by mercury chloride concentration in media. Nitrite and nitrate syntheses were dose-dependently decreased by mercury chloride added in culture media. These results reported here suggest that the disorder of cell mediated immunity by mercurials could be related to the inhibition of nitric oxide synthesis which seems to be caused by the inhibition of metabolism of cells.

A Study on Working Environment and Health Status of Workers in Some Dyeing Factories / 대한산업의학회지

This study was carried out to evaluated the actual conditions of working environment and health status of workers and search more effective health management method of workers in some dyeing factories. This study was conducted from April 1 to October 30, 1992, for 426 workers in two dyeing factories and an electric wire making factories. Among 324 workers in two dyeing factories, 57.5% were male and 42.5% were female. Most of the engaged workers had less than 2 years of working carrier and aged 30 years or below. The used chemical substances exceeding 1 ton per a month were sodium hydroxide(NaOH), hydrogen peroxide(H2O2), sodium chlorite(NaClO2), sodium sulfate(Ma2SO4), sodium carbonate(Na2CO3), and sodium hydrosulfite(Na2S2O4). The used chemical dyes exceeding 100kg per a month were suncion blue H-ERD, levafix brilliant red E-4BA, suncion yellow E-3G, and remazol black B. As the allowable exposure time by governmental threshold limit valuses to industrial noise levels in 90 dBA for 8 hours. Average noise levels of the individual plants were ranged from 75 to 95 dB (A). The TLV for total cotton dust in 2.0mg/m3. Average cotton-dust concentration in these working environmental air were ranging from 0.2-1.3mg/m3. The TLV chlorine, acetic acid and formic acid are 1 ppm, 10 ppm & 5ppm, respectively. The range of chlorine, and acetic and formic acid concentration in these working environmental air were detected 0.2-1.6 ppm and at trace level. The accident by chemical substances and dyes was not found on these working environment. From the physical examination and Todai Health Index scores results, there was no significant correlation between the used chemical substances and the diseases, such as bronchial asthma, other hyperreactive respiratory diseases and contact dermatitis. It was suggested that long term survey should be performed to detect the occupational health problem on these working environment.

Metallothionein induction and its protective effect in liver and kidney of rats exposed to cadmium chloride / 예방의학회지

Tolerance to several toxic effects of cadmium, including lethality has been shown following pretreatment with cadmium and zinc. This study was designed to determine if tolerance also develops to Cd-induced hepatotoxicity and renal toxicity. Three groups of rats (A, B, C), each consisting of 16 rats, were studied and each group was divided into four subgroups (1, 2, 3, 4), 4 rats for each subgroup. Rats were subcutaneously pretreated with saline (A), CdCl2(0.5 mg/kg, B), and ZnCl2 (13.0 mg/kg, C) during time periods of 1~6 weeks. At the end of the period, rats were challenged with CdCl2 (3.0, 6.0 and 9.0 mg/kg, ip). After giving the challenge dose, cadmium and metallothionein (MT) concentrations were determined and also observed the histologic change in liver and kidney. The concentration of cadmium in liver and also observed the increased dose-dependently to the challenge dosage. These data indicate the kidney is a major target organ of chronic cadmium poisoning, and suggest that cadmium induced hepatic injury, via release of Cd-MT, may play and important role in the nephrotoxicity observed in response to long-term exposure to cadmium. In addition, histologic examination of group A2, A3 and A4 revealed moderate to severe cadmium toxicity, evidenced by infiltration of inflammatory cells, cell swelling, pyknosis, enlarged sinusoids and necrosis in liver, and tubule cell necrosis and degeneration in kidney. However, MT concentrations in liver and kidney were increased by the pretreatment of CdCl2 and ZnCl2 and their morphological findings were not significantly changed, comparing with control group. Higher MT concentration in liver and kidney observed in the pretreated groups constitutes a plausible explanation of the protective effects of pretreatment against the cadmium toxicity after challenge dosing.

Selenium Effect on the Frequency of SCEs Induced by Heavy Metals in Human Lymphocytes / 예방의학회지

The protective effect of sodium selenite (Na2SeO3) against the cytogenetic toxicity of heavy metals was investigated on human whole-blood cultures in relation to induction of sister chromatid exchange(SCE) in secondary metaphase chromosome. Methlmercury chloride (CH3HgCl), cadmium chloride (CdCl2), Potassium dichromate (K2Cr2O7), and sodium selenite caused to the typically dose-dependent increase in sister chromatid exchanges (SCEs) by the concentrations ranging from 0.3 micro M to 10 micro M. However, the inductions of sister chromatid exchanges by methymercury chloride or cadmium chloride were inhibited by the simultaneous addition of sodium selenite 1.2 micro M. The frequencies of SCE were decreased to the level of control in the molar ratios as 2 : 1, 1 : 1, 1 : 2, and 1 : 4 of selenium selenite vs. methylmercury chloride, and as 1 : 1 and 1 : 2 of selenium selenite vs. cadmium chloride, while the frequencies of SCE induced by potassium dichromate were not changed by the addition of sodium selenite in culture condition. Mitotic indices were decreased in the higher concentrations of chemicals and not significantly changed by the simultaneous addition of sodium selenite to the culture condition containing each chemicals.

Effect of Several Heavy Metals on the Frequencies of Sister Chromatid Exchanges and Chromosomal Aberrations in Human Lymphocytes / 예방의학회지

To assay the cytogenetic toxicity of NiCl, K2Cr2O7CdC12, and HgC12, the frequencies of sister chromatid exchanges(SCEs) and chromosomal aberrations were observed in the metaphase chromosomes of the human lymphocytes which were cultured with above materials. The frequencies of SCEs are dose-dependently increased by all materials in this experiment. Chromosomal aberrations, especially gap and break, are increased by the nickel and chromic compounds, while not significantly increased by the cadmium and mercurial compounds. This results indicate the dose dependent relationship between the frequencies of SCEs and the concentrations of the heavy metals, but the increasing rates of the SCEs induced by the heavy metals are less sensitive than other mutagens or carcinogens which were confirmed.

Effects of Nickel Compounds on Sister Chromatid Exchanges and Chromosome Aberrations in Human Cultured Lymphocytes / 대한산업의학회지

Nickel is a carcinogen in nickel refinery workers. Few chromosome studies have been performed on nickel toxicity. Therefore, this study was performed to investigate cytogenetic toxicity of nickel in human cultured lymphocytes by chromosome aberration, and sister chromatid exchange (SCE) which is a sensitive indicator of carcinogen and mutagen. The results indicate that nickel chloride and nickel sulfate led to a increase in SCE frequencies very significantly, although absolute value of SCE was low. In chromosome aberration, chromosome gap was increased to increment of concentration while chromosome break was not.

A Study on the Heavy Metal Contents of Soil and Rice in the Kum River Basin / 예방의학회지

This study was carried out to investigate the heavy metal contents and their correlations between paddy soil and brown rice near the Kum-River area. In this study, eighty soil samples and forty brown rice samples were taken from the paddy soil. The contents of heavy metals were measured by flame atomic absorption spectrophotometry. The results were as follows: 1. The average contents of soluble heavy metals in surface soil were Cd 0.19, Cu 15.31, Zn 18.10 and Pb 9.08 ppm. The average contents of soluble heavy metals in subsurface soil were Cd 0.19, Cu 14.52, Zn 17.75 and Pb8.11 ppm. There wan no statistically significant difference between the two layers. 2. The contents of Cu, Zn and Pb of Taejeon(S6) and Cd of Sinbyung(S5) in surface soil were higher than those of other areas. The contents of Cd and Cu of Taejeon(S6) and Zn and Pb of Kumnam(S3) in brown rice were higher than those of other areas and four heavy metals in soil and brown rice of Simchon(S7) were lower than those of other areas. 3. The ratio of soluble contents(Cd : Cu : Zn : Pb) in surface soil was 1 : 79 : 93 : 47, that of soluble contents in subsurface soil was 1 : 79 : 94 : 43, and that of total contents in brown rice was 1 : 84 : 294 : 12. 4. The correlations of the content between soluble heavy metals in surface(0-15 cm depth) soil total heavy metals in brown rice was found to be order of Cd>Cu>Zn>Pb. The correlations of the content between soluble heavy metals in subsurface(20-30 cm depth) soil and total heavy metals in brown rice was found to be order of Cu>Cd>Zn>Pb.

Effects of Anticancer Agents on Cell Cycle Kinetics and Sister Chromatid Exchanges in Cultured Human Lymphocytes / 예방의학회지

Sister chromatid exchanges (SCEs) observed by means of bromodeoxyuridine substitution and fluorescence plus Giemsa (FPG) technique were proposed as a sensitive and quantitative assay for mutagenicity and cytotoxicity in short-term cultures of phytohaemagglutinin (PHA)-stimulated human lymphocytes. Therefore, this study was carried out to investigate the relation between anticancer agents and cytotoxic effects. Chromosomal analysis was performed on metaphase cells that had divided one, two, or three or more times after treatment for SCEs, mitotic indices (MI) and cell cycle kinetics by FPG technique. The results indicate that anticancer agents led to a dose dependent increase in SCE frequency except methotrexate. But, highly inhibited mitotic indices and delayed cell cycle kinetics were observed except for cyclophosphamide. The author suggest that the difference of SCE frequency is due to the differences in the cytotoxic action of anticancer agents, but although the induction of SCEs has a correlation with cell cycle delay, in some cases the induction of SCEs is not always related to cell cycle delay because of different cytotoxic action of anticancer agents.

A study on the Heavy Metal Concentrations and Their Interrelationships in Women's Blood and Urine in small towns / 예방의학회지

The results of this study which had been investigated for the purpose of analyzing heavy metal concentrations in women's blood and urine, their correlation degree and significance of cadmium as indicator of accumulated heavy metals are as follows. 1) In blood, concentrations of Cd, Pb, Cu and Zn are respectively 0.0110+/-0.14 ug/ml, 0.208+/-138 ug/ml, 0.899+/-0.153 ug/ml and 5.432+/-1.020 ug/ml. 2) In urine, concentrations of Cd, Pb, Cu and Zn are respectively 0.003+/-0.12 ug/ml, 0.025+/-0.18 ug/ml, 0.013+/-0.12 ug/ml and 0.277+/-0.192 ug/ml. 3) Correlation coefficients between blood and urine are only significant in Zn (r=0.363, p<0.01). 4) In blood, correlation coefficients of Cd concentration and Pb, Zn are respectively 0.518 (p<0.01). 5) Correlation coefficients between Cd concentration in blood and Pb, Cu and Zn in urine are respectively r=-0.012, r=0.027, r=0.241 (p<0.05), and only Cd concentration and Zn is significant.

Effects of Mitomycin C on Sister Chromatid Exchanges in Cultured Human Lympocytes / 예방의학회지

Sister chromatid exchanges(SCEs) and cell cycle kinetics were proposed as a sensitive and quantitative assay for mutagenicity and cytotoxicity in short-term cultures of phytohemagglutinin(PHA)-stimulated human lymphocytes. Therefore, this study was performed to investigate the relation between the cytotoxic effects and sister chromatid exchanges. The results are summarized as follows: 1) The frequency of SCEs per cell are 13.1+/-2.8 in the lower concentration of 6.25x10(-9) M and 75.8+/-8.2 in the highest concentration of 1.00+/-10(-7) M. Mitotic index is decreased in the higher concentration of mitomycin C. The result indicates that mitomycin C led to a dose dependent increase in SCE frequency, but decrease in mitotic index. 2) Chromosomal analysis was performed on metaphase cells that have divided one, two, and three or more times for cell cycle kinetics by fluorescence-plus-Giemsa(FPG) technique. According to the increased but the cells of third division are greatly decreased. 3) The frequency of SCEs per chromosome by chromocomal group are decreased gradually from A group to G group. But relationships between specific chromosomal group and SCEs frequency are not found.