| 1. Object and methodManganese is an essential trace element of the body, and it has important physiological function. It is a kind of actived component and cofactor of much enzyme. It can active some enzyme, and takes part in lots of biochemical reactions, however, exposure to too much manganese can lead to manganese intoxication. Chronic manganese intoxication mostly impairs nervous system, especially of extrapyramidal malfunction, and accompanying with psychic symptom.The toxicity of manganese is known more than one hundred year, but we know little about primeval examination of neurotoxicity of manganese and mechanism of its toxicity. Now, with improvement of productive environment, most of developed countries and some developing countries have controlled manganese intoxication in some degree, but the chronic effect leaded by the low level and long time exposed to manganese, and "subclinical intoxication" now become more severe than before. According the level of the science at present, behavioral index can detect and reflect subclinical impairment of central nervous system. Neurobehavioral test has the advantage for its simplicity and no wound and good sensitivity, now it is mostly used as a way to detect the primeval impairment of the toxicant to the body. Because of difference among formation and condition of the test and explanation of examiner, the results of different researcher are often difficult to compare. Since Baker developed computerized neurobehavioral evaluations system, the neurobehavioral test had become roboticized and normative and the result could be recorded and saved, and the reliability and validity and comparison was improved.we used the computerized neurobehavioral evaluations system (Chinese version, NES-C3)compiled by medical college of fudan university. It included 20 subtests. Because it was the first time that NES-C3 was used as a test for the workers exposed to manganese, we tried to select some sensitive subtests to detect the subclinical impairment of workers exposed to manganese. 100 manganese-exposed workers and 26 non-exposed workers were chosen as subjects, then 11 subtests were applied to them. Workers were divided into lowly manganese-exposed group(CEI<5) and highly manganese-exposed group(CEI>) by the number of cumulative exposure index(CEI). Every worker was tested by a professionalperson.43 manganese-exposed workers were selected as exposed group and 30 non-exposedworkers as control group. Drawing 4ml blood from the vein of elbow, putting 1ml blood into Ep tubes, then using mixed acid digest the blood, the content of blood Mn, Zn, Fe and Cu was determined by graphite stove atomic absorption method, and the serum was drawn from the remainder 3 ml blood. The activity of NOS was determined by NOS catalyzed L-Arg method.All the statistical analysis was done by SAS8.1 with the computer. 2. Result1.The manganese-exposed workers were significantly with the control in mood, digit-symbol substitution, visual simple time testing and cursor tracing (P<0.05). Results of correlation analysis showed that there was dose-effect relationship between cumulative exposure to manganese and changes of neurobehavioral functions.2.The content of blood manganese of manganese-exposed group was significantly higher than the control (P<0.01). The bioactivity of NOS was significantly lower than control (P<0.05). The linear correlation could be shown between variation of bioactivity of serum NOS and blood manganese(r=-0.358,P<0.05). Besides blood Zn of the manganese-exposed group was significantly lower than the control, There were no significant difference in blood Cu, Zn, Fe between manganese-exposed group and control. 3. Conclusion1. The results of mood states, digit-symbol substitution, cursor tracing and visual simple time testing were corresponding with traditional test by hand, and these subtests were sensitive. The difference was not significant about the subtests reflecting memory function. There were two reason for this: the first may be that the subtests reflecting memo... |
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