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- Nitric Oxide-Mediated Cytotoxicity of Manganese in Basal Ganglia Neuronal Cells.
- Dong Hoon Shin, Yong Wook Jung, Jae Hoon Bae, Dae Kyu Song, Won Kyun Park, Bok Hyun Ko, Doo Hie Kim
- Korean J Prev Med. 1999;32(4):459-466.
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Abstract
PDF - OBJECTIVES
We have investigated to manifest whether manganese-induced neurotoxicity is mediated by nitric oxide(NO) in the rat primary neuronal cultures and assess the effect of Mn2+ on the N-methyl-D aspartate(NMDA) receptors. METHODS: We have used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay to examine the effect of cytotoxicity of MnCl2 in neuronal cells . NO production was determined by measuring nirites, a stable oxidation product of NO. The neurons in the rat that contains neuronal nitric oxide synthase(nNOS) were examined by immunofluorescence and confocal microscopy. The effects of Mn2+ on the NMDA receptors was assesed by the whole cell voltage clamp technique. RESULTS: We showed that the NO release and NOS expression were increased with 500uM MnCl2 treatment and an NOS inhibitors, NG-nitro-L-arginine , prevented neurotoxicity elicited by manganese. In the electrophysiological study, Mn2+ does not block or activate the NMDA receptors and not pass through the NMDA receptors in a neurons of basal ganglia. CONCLUSIONS: It is concluded that manganese neurotoxicity in basal ganglia was partially mediated by nitric oxide in the cell culture model. -
Summary
- Study on the Exposure Levels of Organic Solvents and Subjective Symptoms of Dry-cleaning Workers.
- Soo Young Kim, Jeong Yun Kim, Yeon Kyeng Lee, Sok Goo Lee, Young Soo Lee, Young Chae Cho, Tae Young Lee, Dong Bae Lee
- Korean J Prev Med. 1998;31(4):628-643.
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Abstract
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- To investigate the exposure levels of organic solvents and subjective symptoms of dry-cleaning workers, 77 male and 52 female dry-cleaning workers who had been worked in a small city of Chungnam province, and a large city, Taejon were selected for the study group. Air concentrations of organic solvents in the working environment were analyzed, and subjective symptoms of dry-cleaning workers were surveyed, from July to August 1996. The results obtained were as follows: 1. The concentrations of organic solvents in the working environment were within permissible TLV-TWA limits. 2. For the 13 symptom clusters, the most frequently complained symptom clusters were fatigue as 71.3%, and followed by depression and urinary disturbances as 53.5% and 51.9%. Other symptom clusters complained were below 50%. 3. Positive response rates of subjective symptoms were significantly higher in worker groups such as lived in a large city, female, higher education level, more frequently alcohol drinking, higher concentration of organic solvent in working environment, work in alone. 4. Workers who had used solvent B showed 2.3 point higher scores of subjective symptoms than those of solvent A. Of the subjective symptoms scores, amnesia and nervousness were higher in solvent B user group than solvent B user group. 5. As a result of factor analysis, 3 factors such as depression, urinary disturbance and neurologic disturbance were selected. 6. As a result of the logistic regression analysis, sex, the number of fellow workers, working time, region, job tenure, smoking, alcohol drinking, ventilating system, concentration of organic solvent in working environment and place of residence were selected for the related variables For the conclusion, even though the concentrations of organic solvents in the working environments of dry-cleaning workers were within permissible limit of TLV-TWA, many dry-cleaning workers complained symptoms, such as fatigue, depression, urinary disturbances and so on. And the factors affecting to the symptoms of dry-cleaning workers were the number of fellow workers, work hours, region, job tenure, smoking and alcohol drinking.
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Summary
- Interaction of Sodium Selenite on Neurotoxicity Induced by Methylmercuric Chloride.
- J S Park, H M Lee, Y Chung, D C Shin, J H Roh, Y H Moon
- Korean J Prev Med. 1992;25(1):13-25.
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Abstract
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- This study was conducted to investigate the mechanism of protective effect by sodium selenite in Methylmercuric chloride neurotoxicity, increasing intracellular Ca2+ concentration of the neuron. Methylmercuric chloride of 3 mg/kg of body weight was administered simultaneously with sodium selenite of 5 mg/kg and pretreatment of sodium selenite via intraperitoneal injection to rats. Also, effect of methylmercuric chloride(25 micrometer, 50 micrometer, 100 micrometer) and sodirum selenite(200 micrometer) on free intrasynaptosomal Ca2+ concentration were studied using the fluorescent Ca2+ indicator fura2 in vitro. After the treatment, at 6, 24, and 48 hours later, mercury in the cerebral cortex, liver and kidney tissues, succinic dehydrogenase activities, adenosin-5'-triphosphate concentration, acetylcholinesterase activities, and intracellular Ca2+ concentration in the cerebral cortex were determined in vivo. Cerebral synaptosomes of rats were incubated with methylmercuric chloride and sodium selenite in Hepes buffer for 10 minutes and free intrasynaptosomal Ca2+ concentration were measured with fura2 in vitro.The results were summarized as follows; 1. The combined administration of CH3HgCl and Na2SeO3 and pretreatment of Na2SeO3 according to time significantly more increased in the cerebral cortex and decreased in the liver, kidney mercury concentrations compared to the administration of CH3HgCl only. 2. The combined administration of CH3HgCl and Na2SeO3 and pretreatment of Na2SeO3 increased more succinic dehydrogense and acetylcholinesterase activities compared to the administration of CH3HgCl only. Particularly pretreatment of Na2SeO3 significantly more compared to the administration of CH3HgCl only. The concentration of adenosine-5'-triphosphate in Na2SeO3 treatment groups revealed a favourable effect compared to the administration of CH3HgCl only. 3. Intracellular Ca2+ concentration in administration of CH3HgCl only was increased significantly more than control group in all test hours but was increased significantly more at 48 hous only after treatment in combined administration of CH3HgCl and Na2SeO3 and pretreatment of Na2SeO3 according to time interval more decreased significantly intracellular Ca2+ concentration compared to the administration of CH3HgCl only. 4. Free intrasynaptosomal Ca2+ concentration in the combined administration of CH3HgCl and Na2SeO3 was decreased (24%-40%) significantly more than the administration of CH3HgCl only. From the above results, the specific dosage of Na2SeO3 decreased increment of intracellular Ca2+ concentration induced by administration of CH3HgCl. These findings suggest the protective mechanism of Na2SeO3 on the neurotoxicity of CH3HgCl.
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